letter and word perception: orthographic structure and visual processing in reading

LETTER AND WORD PERCEPTION

ADVANCES IN

PSYCHOLOGY 4

Editors

G. E. STELMACH

P. A. VROON

NORTH-HOLLAND PUBLISHING COMPANY AMSTERDAM * NEW YORK * OXFORD

LETTER AND WORD PERCEPTION

Orthographic Structure and Visual Processing in Reading

Dominic W. MASSARO Glen A. TAYLOR

Richard L. VENEZKY James E. JASTRZEMBSKI

Peter A. LUCAS and

Wisconsin Research and Development Center for Individualized Schooling

University of Wisconsin

1980

NORTH-HOLLAND PUBLISHING COMPANY AMSTERDAM * NEW YORK * OXFORD

Copyright 1980 -The Board of Regentsof the University of Wisconsin System

Copyright is claimed until 1990. Thereafter all portionsof this work covered by this copyright will be in the public domain. Thiswork was developed under agrant from the National Institute of Education, Department of Health, Education, and Welfare. However, the content does not necessarily reflect the position or policy of that Agency, and no official endorsement of these

materials should be inferred.

ISBN: 0 444 85493 2

Publishers:

NORTH-HOLLAND PUBLISHING COMPANY AMSTERDAMoNEW YORK. OXFORD

Sole distributors for the U.S.A. and Canada:

5 2 VANDERBILT AVENUE, NEW YORK, N.Y. 10017

ELSEVIER NORTH-HOLLAND, INC.

Library of Congress Cataloging in Publieation Data

Main entry under title:

Letter and vord perception.

(Advances in psychology ; 4) Includes bibliopaphical references and indexes. 1. Reading. 2. Word recognition. 3. English

langupee--Alphabet. 4. Reading, Psychology of. I. M688az.0, Dominic W. 11. Series: Advauces in psychology (Amsterdam) 4. LBlO#O.L47 428.4 80-14350

PRINTED IN THE NETHERLANDS

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... t o c o m p l e t e l y a n a l y z e what w e d o when w e r e a d would a l m o s t b e t h e acme o f a p s y c h o l o g i s t ' s a c h i e v e m e n t s , f o r i t would b e t o d e s c r i b e v e r y many o f t h e most i n t r i c a t e w o r k i n g s o f t h e human mind , a s w e l l a s t o u n r a v e l t h e t a n g l e d s t o r y o f t h e mos t r e m a r k a b l e s p e c i f i c p e r f o r m a n c e t h a t c i v i l i z a t i o n h a s l e a r n e d i n a l l i t s h i s t o r y .

T h e s e words a r e no l e s s a p p r o p r i a t e t o d a y t h a n t h e y were when Edmund Burke Huey c o n f r o n t e d t h e c h a l l e n g e of u n d e r s t a n d i n g r e a d i n g i n 1908 . And a l t h o u g h m o s t l i t e r a t e s o c i e t i e s d e v o t e v a l u a b l e f i n a n c i a l and human r e s o u r c e s t o u n d e r s t a n d i n g r e a d i n g , i t o f t e n seems a s i f w e a r e no n e a r e r t o a c h i e v i n g t h i s g o a l . However, some p r o g r e s s i s a p p a r e n t . I t is g e n e r a l l y a g r e e d t h a t r e a d i n g i n v o l v e s t h e u t i l i z a t i o n of a v a s t r a n g e o f p e r f o r m a n c e s k i l l s a l o n g w i t h t h e a c t i v e a p p l i c a t i o n o f t h e knowledge r e s o u r c e s o f t h e r e a d e r . The g o a l f o r t h e r e s e a r c h e r , i s t o d e s c r i b e e a c h o f t h e s k i l l s and t o e v a l u a t e how knowledge c o n t r i b u t e s t o t h e s k i l l e d p e r f o r m a n c e .

Our r e s e a r c h i n v e s t i g a t e s how knowledge o f t h e o r t h o g r a p h y ( r u l e s o f s p e l l i n g ) is a c t i v e l y engaged i n l e t t e r and word p e r c e p t i o n o f s k i l l e d r e a d e r s . As m i g h t b e e x p e c t e d , o u r r e s e a r c h e n t e r p r i s e had i t s s h a r e o f b o t h s u b s t a n t i v e a d v a n c e s i n o u r u n d e r s t a n d i n g o f b a s i c p s y c h o l o g i c a l p r o c e s s e s and d i s t r a c t i n g g l a n c e s a t some o f t h e m i n d ' s b e w i l d e r i n g i n c o n s i s t e n c i e s . Our g o a l i n t h i s monograph is t o communica te b o t h t h e p r o g r e s s and some o f t h e d i s t r a c t i o n t h a t we

vi i

Preface

v i i i PREFACE

e x p e r i e n c e d . Because o f t h e d e t a i l e d p r e s e n t a t i o n s o f v a r i o u s d e s c r i p t i o n s o f o r t h o g r a p h i c s t r u c t u r e , t h e ex tended s e r i e s o f e x p e r i m e n t a l s t u d i e s , and t h e f i n e - g r a i n e d a n a l y s e s o f t h e c o n t r i b u t i o n of many d e s c r i p t i o n s o f o r t h o g r a p h i c s t r u c t u r e , piecemeal p u b l i c a t i o n s o f t h i s r e s e a r c h e f f o r t would have been i n a p p r o p r i a t e . T h i s monograph p r o v i d e s t h e c h a l l e n g e of n o t o n l y communicating a p r o t r a c t e d r e s e a r c h e n t e r p r i s e b u t a l s o a n i l l u m i n a t i n g and i n t e r n a l l y - c o n s i s t e n t a c c o u n t o f how r e a d e r s u t i l i z e knowledge o f o r t h o g r a p h i c s t r u c t u r e i n l e t t e r and word p e r c e p t i o n . The s u c c e s s o f t h i s work w i l l be e v a l u a t e d by t h e r e s e a r c h e r , and m u s t s t a n d t h e t e s t o f i t s a p p l i c a b i l i t y t o reading i n s t r u c t ion.

Given t h e r e l a t i v e l y l a r g e number of new e x p e r i m e n t a l s t u d i e s t o be r e p o r t e d , w e d e c i d e d t o o m i t t h e unimpor tan t d e t a i l s o f t h e method, p r o c e d u r e , and r e s u l t s i n t h e a c t u a l d i s c u s s i o n o f t h e e x p e r i m e n t s i n Chapter 4 . However, s i n c e t h i s i n f o r m a t i o n is s t i l l of i n t e r e s t t o many p o t e n t i a l r e a d e r s and r e s e a r c h e r s , i t h a s been p laced i n a p p e n d i c e s a t t h e end of Chapter 4 . Each e x p e r i m e n t a l s t u d y i s numbered i n Chapter 4 and i t s appendix is g i v e n t h e same number. By p l a c i n g unnecessary d e t a i l s i n a p p e n d i c e s , i t is e a s i e r t o m a i n t a i n t h e l o g i c a l c o n t i n u i t y i n t h e p r e s e n t a t i o n of t h e e x p e r i m e n t a l s t u d i e s . When n e c e s s a r y , t h e r e a d e r can a lways t u r n d i r e c t l y t o t h e r e l e v a n t appendix f o r a d d i t i o n a l i n f o r m a t i o n .

I n a d d i t i o n , Appendix 5.1 g i v e s t h r e e performance measures f o r each o f o u r 200 s t i m u l u s i t e m s so t h a t t h e i n t e r e s t e d i n v e s t i g a t o r c a n t e s t a d d i t i o n a l d e s c r i p t i o n s o f o r t h o g r a p h i c s t r u c t u r e w i t h t h e s e d a t a . S i n c e s u b l e x i c a l p o s i t i o n - s e n s i t i v e s i n g l e - l e t t e r and bigram c o u n t s a r e i m p o r t a n t components o f o r t h o g r a p h i c s t r u c t u r e , Appendix 5 . 2 and 5.3 p r e s e n t n o r m a t i v e c o u n t s based on a sample o f roughly o n e m i l l i o n words o f p r i n t e d t e x t . The o n l y c o u n t s c u r r e n t l y a v a i l a b l e i n p r i n t a r e based on a sample o n l y 2 % a s l a r g e . These c o u n t s s h o u l d be v a l u a b l e t o r e s e a r c h e r s and e d u c a t o r s i n t e r e s t e d i n t h e normat ive s t r u c t u r e of Eng 1 i s h o r t h o g r a p h y .

The pr imary o b j e c t i v e of t h i s monograph is t h e p r e s e n t - a t i o n o f our new e m p i r i c a l and t h e o r e t i c a l r e s e a r c h . Because of s p a c e l i m i t a t i o n s , we were unable t o rev iew much o f t h e o t h e r r e l e v a n t r e s e a r c h i n l e t t e r and word p e r c e p t i o n . For rev iews o f t h i s r e s e a r c h , t h e r e a d e r is r e f e r r e d t o A l l p o r t ( 1 9 7 9 ) , Baron ( 1 9 7 8 ) , E s t e s (1977, 1 9 7 8 ) , Gibson and Levin ( 1 9 7 5 ) , Henderson ( 1 9 7 7 ) , Johnson (19771, Krueger ( 1 9 7 5 ) ,

PREFACE ix

Massa ro ( 1 9 7 5 , 1 9 7 8 , 1 9 7 9 b , i n p r e s s ) , and P o l l a t s e k and Carr ( 1 9 7 9 ) .

T h i s r e s e a r c h i s t h e ou tcome o f c o n t r i b u t i o n s o f f i v e r e l a t i v e l y d i s p a r a t e r e s e a r c h e r s . I n time, t h e need t o u n d e r s t a n d l e t t e r and word p e r c e p t i o n became t h e d r i v i n g , f o r c e and o u r o r i g i n a l b i a s e s and b e l i e f s were e v e n t u a l l y m o d i f i e d by a c t u a l e x p e r i m e n t a t i o n and t h e o r t i c a l tests. I f t h i s c o n t r i b u t i o n b e n e f i t s r e a d i n g r e s e a r c h h a l f a s much a s i t b e n e f i t e d e a c h o f t h e p a r t i c i p a n t s f rom t h e c o l l a b o r a t i v e e f f o r t s , t h e n t h e p r o j e c t c a n b e c o n s i d e r e d t o b e a s u c c e s s .

T h i s r e s e a r c h e f f o r t h a s b e e n s u p p o r t e d by f u n d s from t h e N a t i o n a l I n s t i t u t e o f E d u c a t i o n t o t h e W i s c o n s i n R e s e a r c h and Development C e n t e r f o r I n d i v i d u a l i z e d S c h o o l i n g , U n i v e r s i t y o f W i s c o n s i n , Mad i son , W i s c o n s i n 53706 U . S . A . J a c k Wende and Rod McCoy c o n t r i b u t e d t o t h e d e v e l o p m e n t o f t h e c o m p u t e r - c o n t r o l l e d r e s e a r c h f a c i l i t i e s . David K l i t z k e was r e s p o n s i b l e f o r some o f t h e compute r programming, S u s a n C h i c o n e t e s t e d some o f t h e s u b j e c t s . J e n n i f e r A r g e l a n d e r e d i t e d and D o r i s King t y p e d t h e m a n u s c r i p t u s i n g a n o t a l w a y s s t r a i g h t f o r w a r d c o m p u t e r - e d i t i n g s y s t e m . Bob Cavey d r e w t h e many g r a p h s . Don Ander son c o n t r i b u t e d t h e ABC p r i n t .

PREFACE vi i

1. READING AND INFORMATION PROCESSING . . . . . . . . . . 1

An Information Processing Model of Reading 2

2. VISUAL INFORMATION . . . . . . . . . . . . . . . . . . 1 1

Early Work 11 Feature Analysis 13 Letter Features 14

3. Orthographic Structure . . . . . . . . . . . . . . . . 23

Statistical Redundancy 24 Phonologically Based Descriptions 29 Rule-Governed Regularity 30

Phonological Constraints 30 Scribal Constraints 31 Morphemic Featukes 3 2 Psychological Assumptions 34 Dichotomy Issue 34

An Initial Algorithm for Rule-Governed Regularity 35

4. EXPERIMENTAL STUDIES . 0 . . . . . . m 37

xi

Contents

xii CONTENTS

M a s s a r o e t a l . 1979 S t u d i e s 38 S t u d y 1: I n i t i a l R e p l i c a t i o n s 47

P r o c e d u r e 47 O r t h o g r a p h i c S t r u c t u r e 49 S i m i l a r i t y E f f e c t s 5 1 T a r g e t - C a t c h D i f f e r e n c e s 55

I n f o r m a t i o n P r o c e s s i n g Model 55 S t u d y 2: P r e c u e V e r s u s P o s t c u e 6 1

O r t h o g r a p h i c S t r u c t u r e 6 3 S i m i l a r i t y E f f e c t s 64 T a r g e t V e r s u s C a t c h T r i a l s 6 5 I n f o r m a t i o n P r o c e s s i n g Model 6 6

O r t h o g r a p h i c S t r u c t u r e 69 S i m i l a r i t y E f f e c t s 70

S t u d y 4 : L i m i t e d Viewing Time 7 1 O r t h o g r a p h i c S t r u c t u r e 7 1 S i m i l a r i t y E f f e c t s 7 2 T a r g e t V e r s u s C a t c h T r i a l s 7 3 D i s c u s s i o n 7 3

S t u d y 3: Mixed-Case 67

S t u d y 5 : Speeded RT T a s k w i t h Good V i s u a l I n f o r m a t i o n 7 3

P r o c e d u r e 7 6 O r t h o g r a p h i c S t r u c t u r e 77

S t u d y 6: Speeded RT Task w i t h Poor V i s u a l I n f o r m a t i o n 7 7

P r o c e d u r e 78 O r t h o g r a p h i c S t r u c t u r e 78

S t u d y 7 : H igh-Accuracy RT Task w i t h P o o r V i s u a l I n f o r m a t i o n 7 9

P r o c e d u r e 79 O r t h o g r a p h i c S t r u c t u r e 79

Summary o f A c c u r a c y and R e a c t i o n

O v e r t J u d g m e n t s 8 1 S t u d y 8 : T y p i c a l i t y R a t i n g s 8 2 S t u d y 9 : P o s i t i o n a l - F r e q u e n c y R a t i n g s 8 5 S t u d y 1 0 : R e g u l a r i t y V e r s u s

Summary of O v e r t J u d g m e n t E x p e r i m e n t s 90

Time E x p e r i m e n t s 8 0

P o s i t i o n a l - F r e q u e n c y J u d g m e n t s 8 7

CONTENTS xiii

A p p e n d i x 4 . 1 D e t a i l s o f M e t h o d , P r o c e d u r e , a n d R e s u l t s o f S t u d y 1: I n i t i a l R e p l i c a t i o n 9 1

Method 9 1 R e s u l t s 9 4

A p p e n d i x 4.1A R u l e s f o r t h e S e l e c t i o n o f O r t h o g r a p h i c a l l y R e g u l a r a n d I r r e g u l a r S t r i n g s 9 6

A p p e n d i x 4 . 1 8 T h e 200 S t i m u l u s Items Used i n S t u d i e s 1-10 9 7

A p p e n d i x 4 . 2 D e t a i l s o f M e t h o d , P r o c e d u r e , a n d R e s u l t s o f S t u d y 2: P r e c u e V e r s u s P o s t c u e 9 9

Method 9 9 R e s u l t s 1 0 0

A p p e n d i x 4 . 3 D e t a i l s o f M e t h o d , P r o c e d u r e , a n d R e s u l t s o f S t u d y 3: M i x e d - C a s e 1 0 1

Method 0 1 R e s u l t s 1 0 1

A p p e n d i x 4 . 4 D e t a i l s o f M e t h o d , P r o c e d u r e , a n d R e s u l t s o f S t u d y 4: L i m i t e d V i e w i n g T i m e 1 0 3

Method 1 0 3 R e s u l t s 1 0 3

A p p e n d i x 4 . 5 D e t a i l s o f M e t h o d , P r o c e d u r e , a n d R e s u l t s o f S t u d y 5 : S p e e d e d RT T a s k w i t h Good V i s u a l I n f o r m a t i o n 1 0 5


A p p e n d i x 4 . 6 D e t a i l s o f M e t h o d , P r o c e d u r e , a n d R e s u l t s o f S t u d y 6 : S p e e d e d RT T a s k w i t h P o o r V i s u a l I n f o r m a t i o n 1 0 8


A p p e n d i x 4 . 7 D e t a i l s o f M e t h o d , P r o c e d u r e , a n d R e s u l t s o f S t u d y 7: H i g h - A c c u r a c y RT T a s k w i t h P o o r V i s u a l I n f o r m a t i o n 111

Method 111 R e s u l t s 111

A p p e n d i x 4 . 8 D e t a i l s o f M e t h o d , P r o c e d u r e , a n d R e s u l t s o f S t u d y 8 : T y p i c a l i t y R a t i n g s 113


A p p e n d i x 4.8A T h e P s e u d o w o r d s Used i n S t u d y 8 1 1 5

xiv CONTENTS

Appendix 4.88 Directions for Typicality Ratings Without Words and for Typicality Ratings with

Pseudowords 116 Appendix 4.8C Directions for Typicality Ratings with

Appendix 4.9 Details of Method, Procedure, and Words 117

Results of Study 9: Positi,onal-Frequency Ratings 118 Method 118 Results 118

Appendix 4.9A Directions for Positional-Frequency

Appendix 4.10 Details of Method, Procedure, and Ratings 119

Results of Study 10: Regularity Versus Positional-Frequency Paired-Judgments 120

Method 120 Results 121

Appendix 4.10A Regularity Instructions for

Appendix 4.108 Positional-Frequency Instructions Paired-Judgments 122

for Paired-Judgments 123

5. STRUCTURAL DESCRIPTIONS . . . . . . . Descriptive Measures 125 Type Versus Token Counts 128 Scale of Frequency 130 Position-Sensitive Versus Position

The Most Effective Frequency Measure Frequency Versus Regularity 138 Within Class Analysis 140 Word Frequency 141 Multiple Regression 141 Summary 142

Insensitive Counts 132

. . . . . . . 125

133

Appendix 5.1 Stimulus Items and Results 143 Appendix 5.2 Single-Letter Positional Frequencies 149

Three-letter Words 150 Four-letter Words 152 Five-letter Words 154 Six-letter Words 156 Seven-letter Words 158

CONTENTS xv

Appendix 5.3 Bigrarn Positional Frequencies 160 Three-letter Words 161 Four-letter Words 172 Five-letter Words 188 Six-letter Words 205 Seven-letter Words 224

6. SUMMARY AND CONCLUSIONS . . . . . . . . . . . . . . . 245

REFERENCES 249 GLOSSARY 263 AUTHOR INDEX 269 SUBJECT INDEX 275

1 Reading and Information Processing

The p r o c e s s e s by which words a r e r e c o g n i z e d d u r i n g r e a d i n g h a v e c o n c e r n e d p s y c h o l o g i s t s and e d u c a t o r s f o r almost a c e n t u r y . The b a s i c a s s u m p t i o n is t h a t a t h o r o u g h u n d e r s t a n d i n g o f t h e p r o c e s s e s i n v o l v e d i n word r e c o g n i t i o n w i l l a f f o r d a m a j o r a d v a n c e i n t h e u n d e r s t a n d i n g o f how p e o p l e r e a d . E v e r y m a j o r t r e a t i s e on r e a d i n g from Huey (1908 /1968) t o G i b s o n and L e v i n ( 1 9 7 5 ) h a s d i s c u s s e d t h i s i s sue a t l e n g t h , b u t g e n e r a l l y h a s c o n c l u d e d , a s d i d Huey ( 1 9 0 8 / 1 9 6 8 , p. 1 0 2 ) , t h a t " i t is v e r y d i f f i c u l t t o d raw f i n a l c o n c l u s i o n s c o n c e r n i n g v i s u a l p e r c e p t i o n i n r e a d i n g . . . ."

R e c e n t l y two d i f f e r e n t p a n e l s wh ich recommended f u n d i n g p r i o r i t i e s i n b a s i c s k i l l s r e s e a r c h t o t h e N a t i o n a l I n s t i t u t e o f E d u c a t i o n a s s i g n e d h i g h p r i o r i t i e s t o s t u d i e s on word r e c o g n i t i o n . C o n s e q u e n t l y , a h i g h p r i o r i t y c u r r e n t l y i s b e i n g g i v e n t o o b t a i n i n g a b e t t e r u n d e r s t a n d i n g o f word r e c o g n i t i o n w i t h s t r e s s on t h e b a s i c s t a g e s of v i s u a l i n f o r m a t i o n p r o c e s s i n g . I n f o r m a t i o n p r o c e s s i n g d u r i n g r e a d i n g is c u r r e n t l y t h e p r i m a r y c o n c e r n o f many e x p e r i m e n t a l p s y c h o l o g i s t s , and t h e r e f o r e , a n e x p a n d i n g body o f e x p e r i m e n t a l d a t a is b e i n g b r o u g h t t o b e a r on t h e s e q u e s t i o n s . S i n c e word r e c o g n i t i o n f o r m s a b r i d g e be tween v i s u a l i n f o r m a t i o n p r o c e s s i n g s k i l l s and c o m p r e h e n s i o n , i t is i m p o r t a n t f o r u n d e r s t a n d i n g how t h e two r e l a t e t o e a c h o t h e r .

R e s e a r c h on word r e c o g n i t i o n p r o c e s s e s is s e e n a s h a v i n g a h i g h p o t e n t i a l f o r improv ing r e a d i n g i n s t r u c t i o n . Good and poor r e a d e r s h a v e been shown t o d i f f e r i n p e r f o r m a n c e o n a v a r i e t y o f g e n e r a l t a s k s b u t u n t i l r e c e n t l y , l i t t l e a t t e m p t h a s been made t o e x p l o r e how c h i l d r e n w i t h d i f f e r e n t l e v e l s o f r e a d i n g a b i l i t y m i g h t d i f f e r i n b a s i c word r e c o g n i t i o n p r o c e s s e s . We b e l i e v e t h a t b a s i c word r e c o g n i t i o n p r o c e s s e s ,

2 CHAPTER 1

once d e f i n e d f o r competent a d u l t r e a d e r s , c a n be used t o a s s e s s word r e c o g n i t i o n a b i l i t i e s of good and poor r e a d e r s i n t h e e l e m e n t a r y g r a d e s . ~f good and poor r e a d e r s u t i l i z e t h e same p r o c e s s e s , b u t d i f f e r i n speed or a c c u r a c y , t h e n r e m e d i a t i o n methods based on common approaches t o r e a d i n g i n s t r u c t i o n would be w a r r a n t e d . However, i f fundamental d i f f e r e n c e s i n v i s u a l r e c o g n i t i o n p r o c e s s e s a r e found, t h e n t o t a l l y d i f f e r e n t remedia l methods would be r e q u i r e d .

The o v e r a l l o b j e c t i v e of t h i s r e s e a r c h p r o j e c t i s t o a s s e s s how t h e r e a d e r ' s h i g h e r - o r d e r knowledge of t h e l a n g u a g e i n t e r a c t s w i t h l o w e r - l e v e l p e r c e p t u a l a n a l y s e s d u r i n g r e a d i n g . The s p e c i f i c q u e s t i o n t h a t is a d d r e s s e d is how t h e r e a d e r ' s a b s t r a c t knowledge a b o u t o r t h o g r a p h i c s t r u c t u r e is combined wi th t h e i n f o r m a t i o n d e r i v e d from v i s u a l f e a t u r a l a n a l y s i s i n word r e c o g n i t i o n . O r t h o g r a p h i c s t r u c t u r e r e f e r s t o t h e s p e l l i n g c o n s t r a i n t s i n a w r i t t e n l a n g u a g e . There is a c o n s i d e r a b l e amount of p r e d i c t a b i l i t y i n E n g l i s h w r i t i n g , f o r example, and t h e r e a d e r may a c t i v e l y u t i l i z e t h i s i n f o r m a t i o n i n word r e c o g n i t i o n . V i s u a l f e a t u r a l a n a l y s i s r e f e r s t o t h e e v a l u a t i o n of component p r o p e r t i e s of l e t t e r s i n t h e c o u r s e of l e t t e r and word r e c o g n i t i o n . Given e v i d e n c e t h a t bo th of t h e s e s o u r c e s o f i n f o r m a t i o n c o n t r i b u t e t o word r e c o g n i t i o n , t h e g o a l i s t o d e f i n e what i n f o r m a t i o n t h e r e a d e r a c t u a l l y u t i l i z e s (what i n f o r m a t i o n i s p s y c h o l o g i c a l l y r e a l ) and t o d e f i n e how t h e s e s o u r c e s of i n f o r m a t i o n a r e i n t e g r a t e d t o g e t h e r i n r e a d i n g . T h i s r e q u i r e s examinat ion of t h e p s y c h o l o g i c a l r e a l i t y of v a r i o u s d e s c r i p t i o n s of v i s u a l f e a t u r e s , of o r t h o g r a p h i c s t r u c t u r e , and of q u a n t i t a t i v e models t h a t d e s c r i b e how v i s u a l f e a t u r e s and o r t h o g r a p h i c s t r u c t u r e a r e i n t e g r a t e d d u r i n g word p e r c e p t i o n and r e c o g n i t i o n .

AN INFORMATION PROCESSING MODEL OF R E A D I N G

E v a l u a t i o n of t h e c o n t r i b u t i o n s of v i s u a l f e a t u r e s and o r t h o g r a p h i c s t r u c t u r e t o word r e c o g n i t i o n r e q u i r e s t h a t we d e s c r i b e i n some d e t a i l t h e p r o c e s s e s involved i n r e a d i n g . The model f o r d e s c r i b i n g t h e s e p r o c e s s e s is p a r t of a more g e n e r a l language p r o c e s s i n g model which has been developed and t e s t e d over t h e p a s t few y e a r s (Massaro, 1975, 1978, 1 9 7 9 a ) . F i g u r e 1.1 p r e s e n t s a s c h e m a t i c r e p r e s e n t a t i o n of t h e s t a g e s of p r o c e s s i n g i n r e a d i n g . A t each s t a g e of p r o c e s s i n g , memory and p r o c e s s components a r e r e p r e s e n t e d . Each memory component ( i n d i c a t e d by a r e c t a n g l e ) c o r r e s p o n d s t o t h e i n f o r m a t i o n a v a i l a b l e a t a p a r t i c u l a r s t a g e of p r o c e s s i n g . Each p r o c e s s

R E A D I N G AND INFORMATION PROCESSING 3

component ( i n d i c a t e d by a c i r c l e ) c o r r e s p o n d s t o t h e o p e r a t i o n s a p p l i e d t o t h e i n f o r m a t i o n h e l d by t h e memory component. The memory components a r e temporary s t o r a g e s e x c e p t f o r long-term memory which is r e l a t i v e l y permanent a n d , i n a d d i t i o n , supplements t h e i n f o r m a t i o n a t some of t h e p r o c e s s i n g s t a g e s . T h i s model p r o v i d e s a framework from which h y p o t h e s e s a b o u t word r e c o g n i t i o n can be d e r i v e d and t e s t e d .

The t y p i c a l t e x t i n r e a d i n g i s a sequence of l e t t e r s and s p a c e s which conform t o o r t h o g r a p h i c , s y n t a c t i c , and s e m a n t i c c o n s t r a i n t s of t h e w r i t t e n language . The a v e r a g e E n g l i s h r e a d e r b e g i n s a t t h e t o p l e f t - h a n d c o r n e r of t h e page and r e a d s each l i n e from l e f t t o r i g h t . The r e a d e r ' s eye movements a c r o s s a l i n e a r e n o t c o n t i n u o u s b u t occur i n a s e r i e s of s h o r t jumps c a l l e d s a c c a d e s . The f i x a t i o n time between s a c c a d e s is r o u g h l y t e n times l o n g e r t h a n t h e s a c c a d e . The t y p i c a l s a c c a d e of 1 t o 2 d e g r e e s r e q u i r e s 2 0 t o 30 msec, whereas f i x a t i o n t ime a v e r a g e s 250 msec ( S h e b i l s k e , 1975; Woodworth, 1 9 3 8 ) . I n i t i a l p r o c e s s i n g of t h e v i s u a l s t i m u l u s m u s t O C C U K d u r i n g t h e f i x a t i o n time because t h e s t i m u l u s p a t t e r n is b l u r r e d d u r i n g a s a c c a d e and i t s d u r a t i o n is t o o s h o r t f o r s u f f i c i e n t p r o c e s s i n g t o o c c u r . During an eye f i x a t i o n , t h e l i g h t p a t t e r n r e f l e c t e d from l e t t e r s i s t r a n s d u c e d by t h e v i s u a l r e c e p t o r s and a p r o c e s s d e t e c t s and t r a n s m i t s v i s u a l f e a t u r e s t o p r e p e r c e p t u a l v i s u a l s t o r a g e ( s e e F i g u r e 1.1). I n our model, w e c a l l t h i s i n i t i a l p r o c e s s f e a t u r e d e t e c t i o n . The f e a t u r e s a r e d e s c r i b e d a s v i s u a l because i t is assumed t h a t t h e r e i s a d i r e c t r e l a t i o n s h i p between t h e s t i m u l u s p r o p e r t i e s of t h e l e t t e r s and

LONG TERM MEMORY

t T

MEMORY MEMORY

F i g u r e 1.1 A s t a g e model of r e a d i n g p r i n t e d t e x t .

CHAPTER 1

t h e i n f o r m a t i o n i n p r e p e r c e p t u a l v i s u a l s t o r a g e . The p a s s i v e t r a n s d u c t i o n of f e a t u r e d e t e c t i o n c o n t r a s t s w i t h t h e a c t i v e c o n s t r u c t i o n of t h e s u b s e q u e n t p r o c e s s i n g s t a g e s . There is no e x a c t one-to-one r e l a t i o n s h i p between t h e i n p u t and o u t p u t of t h e f o l l o w i n g p r o c e s s i n g s t a g e s s i n c e t h e s e l a t e r s t a g e s a c t i v e l y u t i l i z e i n f o r m a t i o n s t o r e d i n long-term memory.

Given t h e se t of v i s u a l f e a t u r e s i n p r e p e r c e p t u a l v i s u a l s t o r a g e , t h e p r i m a r y r e c o g n i t i o n p r o c e s s a t t e m p t s t o t r a n s f o r m t h e s e i s o l a t e d f e a t u r e s i n t o a sequence of l e t t e r s and s p a c e s i n s y n t h e s i z e d v i s u a l memory. To d o t h i s , t h e p r i m a r y r e c o g n i t i o n p r o c e s s can u t i l i z e i n f o r m a t i o n h e l d i n long-term memory which f o r t h e accomplished r e a d e r i n c l u d e s a l i s t of f e a t u r e s f o r each l e t t e r of t h e a l p h a b e t a l o n g w i t h i n f o r m a t i o n a b o u t t h e o r t h o g r a p h i c s t r u c t u r e of t h e l a n g u a g e . The p r i m a r y r e c o g n i t i o n p r o c e s s u t i l i z e s both t h e v i s u a l f e a t u r e s i n p r e p e r c e p t u a l s t o r a g e and knowledge of o r t h o g r a p h i c s t r u c t u r e i n i t s s y n t h e s i s of t h e l e t t e r s t r i n g s . The t ime-honored b e l i e f t h a t r e c o g n i t i o n of l e t t e r s t r i n g s becomes p r o g r e s s i v e l y e a s i e r a s t h e s t r i n g s more c l o s e l y approximate words i m p l i e s t h a t r e a d e r s c a p i t a l i z e on t h e p r e s e n c e of o r t h o g r a p h i c s t r u c t u r e . Recogni t ion u s u a l l y means t h e p r o c e s s of d i s - c r i m i n a t i n g , i d e n t i f y i n g , and c o r r e c t l y o r d e r i n g t h e l e t t e r s of a l e t t e r s t r i n g (Smi th , 1 9 7 1 ) . Given t h i s i n t e r p r e t a t i o n of r e c o g n i t i o n , t h e f a c i l i t a t i n g e f f e c t of o r t h o g r a p h i c s t r u c t u r e on l e t t e r - s t r i n g r e c o g n i t i o n m u s t a l m o s t be t r u e by d e f i n i t i o n . Recogni t ion i n v o l v e s a c c e s s i n g knowledge b u i l t up through e x p e r i e n c e . I t is o n l y n a t u r a l t h a t a r e a d e r ' s e x p e r i e n c e w i t h words w i l l g e n e r a l i z e more t o w o r d l i k e t h a n nonwordl ike s t r i n g s . Our g o a l s i n t h i s r e s e a r c h endeavor a r e t o p r o v i d e a b e t t e r u n d e r s t a n d i n g of t h e r e c o g n i t i o n p r o c e s s and t o e v a l u a t e which a s p e c t s of o r t h o g r a p h i c s t r u c t u r e t h e r e a d e r knows and u t i l i z e s .

The c e n t r a l assumpt ion a d d r e s s e d h e r e i s t h a t o r t h o g r a p h i c s t r u c t u r e i n f l u e n c e s p e r c e p t u a l r e c o g n i t i o n ( p r i m a r y r e c o g n i t i o n i n our m o d e l ) , i n a d d i t i o n t o o t h e r i n f l u e n c e s a t l a t e r s t a g e s of p r o c e s s i n g . We b e l i e v e t h a t o r t h o g r a p h i c s t r u c t u r e a l s o f a c i l i t a t e s p r o c e s s i n g from a p e r c e p t u a l t o a c o n c e p t u a l l e v e l ( s e c o n d a r y r e c o g n i t i o n i n our m o d e l ) . By f o c u s i n g on t h e f a c i l i t a t i n g e f f e c t s of o r t h o g r a p h i c s t r u c t u r e on v i s u a l p e r c e p t i o n , w e have a l i g n e d o u r s e l v e s w i t h a t r a d i t i o n over 100 y e a r s o l d concerned w i t h how knowledge i n f l u e n c e s p e r c e p t i o n . James (1890/1950, p. 4 4 4 ) c a p t u r e d t h e s p i r i t of t h e work begun by Wundt w i t h t h e o f t e n quoted s t a t e m e n t , " . . . t h e o n l y t h i n g s which w e commonly s e n a r e t h o s e which w e p r e p e r c e i v e . "


In our model , t h e p r imary r e c o g n i t i o n p r o c e s s e v a l u a t e s t h e f e a t u r e s i n p r e p e r c e p t u a l v i s u a l s t o r a g e and compares o r matches t h e s e f e a t u r e s t o d e s c r i p t i o n s of p e r c e p t u a l u n i t s i n long-term memory. A p e r c e p t u a l u n i t o r p r o t o t y p e r e p r e s e n t s each of t h e l e t t e r s i n long- te rm memory a s i t would be i d e a l l y r e p r e s e n t e d i n p r e p e r c e p t u a l v i s u a l s t o r a g e . The p r i m a r y r e c o g n i t i o n p r o c e s s s e e k s f o r each l e t t e r p o s i t i o n t h e p e r c e p t u a l p r o t o t y p e t h a t p r o v i d e s t h e b e s t match t o t h e f e a t u r a l i n f o r m a t i o n . I t is a t p r imary r e c o g n i t i o n t h a t o r t h o g r a p h i c s t r u c t u r e r e d u c e s u n c e r t a i n t y o r c o n t r i b u t e s i n f o r m a t i o n . The outcome of pr imary r e c o g n i t i o n i s , t h e r e f o r e , t h e j o i n t p r o d u c t of f e a t u r a l i n f o r m a t i o n i n p r e p e r c e p t u a l v i s u a l s t o r a g e and knowledge of l e t t e r c o n s t r a i n t s i n long- te rm memory.

S i n c e t h e r e a r e a l i m i t e d number of ways t h a t s e q u e n c e s of l e t t e r s and l e t t e r g r o u p s c a n be assembled t o form E n g l i s h words, knowledge of t h e s e s e q u e n c e s can h e l p t h e r e a d e r t o r e s o l v e t h e l e t t e r s i n s t r i n g s t h a t conform t o t h e l a n g u a g e ( c f . Massaro, 1975, Chapter 7 ) . I t a l s o h a s been h y p o t h e s i z e d t h a t t h i s knowledge c a n a s s i s t t h e r e a d e r i n d e t e r m i n i n g t h e r e l a t i v e p o s i t i o n s of l e t t e r s once t h e y a r e r e c o g n i z e d ( E s t e s , 1975a , 1 9 7 5 b ) . For example, g i v e n t h e l e t t e r s &, knowledge of o r t h o g r a p h i c s t r u c t u r e d o e s n o t a l l o w t h e s e l e t t e r s t o be read i n t h e o p p o s i t e o r d e r . However, G e o f f r i o n (1976) found t h a t t h e c o n t r i b u t i o n of o r t h o g r a p h i c s t r u c t u r e is n o t dependent on d e t e r m i n i n g t h e r e l a t i v e p o s i t i o n s of l e t t e r s . I n a d d i t i o n , r e c e n t r e s e a r c h by MaSSaKO (1979a) found a l a r g e e f f e c t of o r t h o g r a p h i c s t r u c t u r e on l e t t e r r e c o g n i t i o n b u t no e f f e c t on t h e d e t e r m i n a t i o n of r e l a t i v e s p a t i a l p o s i t i o n . I n t h e p r e s e n t r e s e a r c h , t h e e x p e r i m e n t s a r e d e s i g n e d such t h a t any f a c i l i t a t i n g e f f e c t of o r t h o g r a p h i c s t r u c t u r e a t p r i m a r y r e c o g n i t i o n m u s t be due t o l e t t e r r e c o g n i t i o n and n o t p o s i t i o n u n c e r t a i n t y .

The p r i m a r y r e c o g n i t i o n p r o c e s s o p e r a t e s on a number of l e t t e r s s i m u l t a n e o u s l y ( i n p a r a l l e l ) . The v i s u a l f e a t u r e s d e t e c t e d a t each s p a t i a l l o c a t i o n d e f i n e a s e t of p o s s i b l e l e t t e r s f o r t h a t p o s i t i o n . The pr imary r e c o g n i t i o n p r o c e s s chooses from t h i s s e t of c a n d i d a t e s t h e l e t t e r a l t e r n a t i v e which h a s t h e b e s t cor respondence i n t e r m s of v i s u a l f e a t u r e s . However, t h e s e l e c t i o n of a b e s t c o r r e s p o n d e n c e can be f a c i l i t a t e d by knowledge of o r t h o g r a p h i c s t r u c t u r e . The pr imary r e c o g n i t i o n p r o c e s s , t h e r e f o r e , a t t e m p t s t o u t i l i z e bo th t h e f e a t u r a l i n f o r m a t i o n i n p r e p e r c e p t u a l s t o r a g e and knowledge a b o u t t h e s t r u c t u r e of l e g a l l a t t e r s t r i n g s . A

c r i t i c a l concern is w i t h t h e i n t e r a c t i o n of t h e s e two s o u r c e s

CHAPTER 1

of i n f o r m a t i o n ; i n our model , i t is assumed t h a t t h e two s o u r c e s of i n f o r m a t i o n make independent c o n t r i b u t i o n s t o pr imary r e c o g n i t i o n (Massaro, 1973, 1975, 1978, 1979b; Thompson & Massaro, 1 9 7 3 ) .

The p r e s e n t a n a l y s i s of t h e f a c i l i t a t i o n of o r t h o g r a p h i c s t r u c t u r e i n l e t t e r r e c o g n i t i o n is i d e n t i c a l i n s p i r i t t o t h e o r i g i n a l a n a l y s i s provided by M i l l e r , Bruner , and Postman ( 1 9 5 4 ) . They observed t h a t t h e number of l e t t e r s c o r r e c t l y r e p o r t e d from a t a c h i s t o s c o p i c e x p o s u r e i n c r e a s e d w i t h i n c r e a s e s i n f a m i l i a r i t y of t h e l e t t e r p a t t e r n . The f a m i l i a r i t y of t h e l e t t e r sequences was v a r i e d by t h e d e g r e e t o which t h e sequence approximated p r i n t e d E n g l i s h (Shannon, 1 9 4 8 ) . U t i l i z i n g t h e t h e o r y of i n f o r m a t i o n developed by Shannon ( 1 9 4 8 ) , however, t h e y observed t h a t t h e number of l e t t e r s r e p o r t e d i s n o t a d i r e c t index of t h e amount of s t i m u l u s i n f o r m a t i o n d e r i v e d from t h e e x p o s u r e i t s e l f s i n c e t h e redundancy of c o n t e x t u a l l y c o n s t r a i n e d s e q u e n c e s is n o t t a k e n i n t o a c c o u n t .

M i l l e r e t a l . (1954) c a l c u l a t e d t h e redundancy o f t h e i r sequences a t e a c h o r d e r of approximat ion t o E n g l i s h u s i n g t h e c o u n t s g i v e n by Shannon (1951) and c o u n t s of t h e i r own. When performance was c o r r e c t e d f o r redundancy, t h e r e was no e f f e c t of f a m i l i a r i t y (see a l s o T u l v i n g , 1 9 6 3 ) . T h i s r e s u l t was i n t e r p r e t e d t o mean t h a t t h e amount o f s t i m u l u s i n f o r m a t i o n r e c e i v e d from t h e e x p o s u r e d i d n o t depend on t h e f a m i l i a r i t y of t h e l e t t e r p a t t e r n . I n te rms of our a n a l y s i s , over two d e c a d e s l a t e r , t h e r e s u l t s c a n be i n t e r p r e t e d t o mean t h a t o r t h o g r a p h i c s t r u c t u r e and v i s u a l i n f o r m a t i o n c o n t r i b u t e independent s o u r c e s of i n f o r m a t i o n i n r e a d i n g .

The c u r r e n t view was d e v e l o p e d , i n p a r t , on t h e b a s i s o f e x p e r i m e n t s c a r r i e d o u t u s i n g t h e Reicher-Wheeler paradigm i n word r e c o g n i t i o n ( R e i c h e r , 1969; Wheeler , 1970; Thompson &

Massaro, 1 9 7 3 ) . I n t h i s paradigm, s u b j e c t s a r e p r e s e n t e d w i t h e i t h e r a t e s t word o r a s i n g l e t e s t l e t t e r f o r a s h o r t d u r a t i o n fo l lowed immediately by a masking s t i m u l u s and two r e s p o n s e a l t e r n a t i v e s . The r e s p o n s e a l t e r n a t i v e s both s p e l l words i n t h e t e s t word c o n d i t i o n ; f o r example, g i v e n t h e t e s t s t i m u l u s WORD, t h e r e s p o n s e a l t e r n a t i v e s ---g and ---E would be p r e s e n t e d . I n t h e c o r r e s p o n d i n g s i n g l e t e s t l e t t e r c o n d i t i o n , - D is p r e s e n t e d and f o l l o w e d by t h e r e s p o n s e a l t e r n a t i v e s g and - K . I n t h e s e s t u d i e s , r e c o g n i t i o n of t h e t e s t word i s a b o u t 1 0 % b e t t e r t h a n r e c o g n i t i o n of t h e t e s t l e t t e r .

Given t h e t w o - a l t e r n a t i v e f o r c e d - c h o i c e c o n t r o l , i t is assumed t h a t t h e r e a d e r u t i l i z e s o r t h o g r a p h i c s t r u c t u r e t o e l i m i n a t e p o s s i b l e a l t e r n a t i v e s d u r i n g t h e p e r c e p t i o n of t h e

R E A D I N G AND INFORMATION PROCESSING

t e s t d i s p l a y (Thompson & Massaro, 1 9 7 3 ) . A s a n example, p r e s e n t e d w i t h t h e t e s t s t i m u l u s WORD and g i v e n r e c o g n i t i o n of t e s t l e t t e r s WOR and a c u r v i l i n e a r segment of t h e f i n a l l e t t e r , t h e r e a d e r c o u l d narrow down t h e a l t e r n a t i v e s f o r t h e f i n a l l e t t e r t o D , 0 , and Q. I f 0 and Q a r e c o n s i d e r e d t o be o r t h o g r a p h i c a l l y i l l e g a l i n t h e c o n t e x t m, t h e n D r e p r e s e n t s an unambiguous c h o i c e . The r e a d e r w i l l t h e r e f o r e p e r c e i v e t h e word WORD g i v e n j u s t p a r t i a l i n f o r m a t i o n a b o u t t h e f i n a l l e t t e r . I f t h e r e a d e r r e c o g n i z e s t h e same c u r v i l i n e a r segment i n t h e c o r r e s p o n d i n g s i n g l e t e s t l e t t e r c o n d i t i o n , however , any of t h e t h r e e l e t t e r s ( D , 0 , and Q ) a r e p o s s i b l e and t h e p e r c e p t u a l s y n t h e s i s w i l l r e s u l t i n D o n l y one o u t of t h r e e times. What is c r i t i c a l i n t h i s a n a l y s i s i s t h a t t h e b e t t e r per formance on words compared t o s i n g l e l e t t e r s i s o b t a i n e d even though t h e v i s u a l f e a t u r a l i n f o r m a t i o n a v a i l a b l e t o t h e p r i m a r y r e c o g n i t i o n p r o c e s s i s e q u i v a l e n t i n t h e word and l e t t e r c o n d i t i o n s . The o r t h o g r a p h i c s t r u c t u r e of t h e word s imply p r o v i d e s an a d d i t i o n a l b u t independent s o u r c e of i n f o r m a t i o n . The f e a t u r a l i n f o r m a t i o n a v a i l a b l e t o t h e r e c o g n i t i o n p r o c e s s d o e s n o t change w i t h changes i n o r t h o g r a p h i c s t r u c t u r e . I n t h i s v iew, a l t h o u g h o r t h o g r a p h i c s t r u c t u r e f a c i l i t a t e s word p e r c e p t i o n , i t d o e s n o t modify t h e f e a t u r e a n a l y s i s of t h e p r i n t e d p a t t e r n (Krueger & S h a p i r o , 1979; Massaro, 1 9 7 9 a ) .

As ure have d i s c u s s e d , one r o l e of o r t h o g r a p h i c s t r u c t u r e is c o n c e n t r a t e d i n t h e p r i m a r y r e c o g n i t i o n p r o c e s s and s e r v e s t o f a c i l i t a t e t h e r e c o g n i t i o n of i n d i v i d u a l l e t t e r s . I n a d d i t i o n , o r t h o g r a p h i c s t r u c t u r e is f u n c t i o n a l a t l a t e r s t a g e s of p r o c e s s i n g , such a s i t s f a c i l i t a t i n g e f f e c t i n s h o r t - t e r m memory (Massaro , i n p r e s s ) . Baddeley ( 1 9 6 4 ) , f o r example, showed t h a t a w e l l - s t r u c t u r e d s t r i n g of l e t t e r s is e a s i e r t o remember and r e c a l l t h a n a random s t r i n g . Whether o r t h o g r a p h i c s t r u c t u r e f a c i l i t a t e s p e r c e p t u a l r e c o g n i t i o n i s a more c o n t r o v e r s i a l i s s u e . We assume t h a t i t is u t i l i z e d i n t h e f o l l o w i n g manner. Upon p r e s e n t a t i o n of a l e t t e r s t r i n g , t h e pr imary r e c o g n i t i o n p r o c e s s b e g i n s i n t e g r a t i n g and s y n t h e s i z i n g f e a t u r a l i n f o r m a t i o n passed on by f e a t u r e d e t e c t i o n t o p r e p e r c e p t u a l v i s u a l s t o r a g e . F e a t u r a l i n f o r m a t i o n i s r e s o l v e d a t d i f f e r e n t r a t e s and t h e r e is some e v i d e n c e t h a t g r o s s f e a t u r e s a r e a v a i l a b l e b e f o r e t h e more d e t a i l e d f e a t u r e s (Massaro & S c h m u l l e r , 1 9 7 5 ) . The p r i m a r y r e c o g n i t i o n p r o c e s s i s f a c e d w i t h a s u c c e s s i o n of p a r t i a l i n f o r m a t i o n s t a t e s . These p a r t i a l v i s u a l i n f o r m a t i o n s t a t e s a r e supplemented w i t h knowledge a b o u t o r t h o g r a p h i c s t r u c t u r e . A s s u m e , f o r example, a n i n i t i a l g h a s been p e r c e i v e d i n a

8 CHAPTER 1

l e t t e r s t r i n g , and t h e f e a t u r e s a v a i l a b l e f o r t h e n e x t l e t t e r e l i m i n a t e a l l a l t e r n a t i v e s e x c e p t c o r g . The p r i m a r y r e c o g n i t i o n p r o c e s s m i g h t s y n t h e s i z e 5 w i t h o u t w a i t i n g f o r f u r t h e r v i s u a l i n f o r m a t i o n , s i n c e i n i t i a l the is n o t a c c e p t a b l e w h i l e i n i t i a l the is.

The p r i m a r y r e c o g n i t i o n p r o c e s s t r a n s m i t s a s e q u e n c e o f r e c o g n i z e d l e t t e r s t o s y n t h e s i z e d v i s u a l memory. F i g u r e 1.1 shows h o r t h e s e c o n d a r y r e c o g n i t i o n p r o c e s s t r a n s f o r m s t h i s s y n t h e s i z e d v i s u a l p e r c e p t i n t o m e a n i n g f u l form i n g e n e r a t e d a b s t r a c t memory. We assume s e c o n d a r y r e c o g n i t i o n a t t e m p t s t o c l o s e o f f t h e l e t t e r s t r i n g i n t o a word. The s e c o n d a r y r e c o g n i t i o n p r o c e s s makes t h i s t r a n s f o r m a t i o n by f i n d i n g t h e b e s t ma tch be tween t h e l e t t e r s t r i n g and a word i n t h e l e x i c o n i n l o n g - t e r m memory. Knowledge o f o r t h o g r a p h i c s t r u c t u r e c a n a l s o c o n t r i b u t e t o s e c o n d a r y r e c o g n i t i o n ; word r e c o g n i t i o n c a n o c c u r w i t h o u t c o m p l e t e r e c o g n i t i o n o f a l l o f t h e component l e t t e r s . G i v e n t h e l e t t e r s & and t h e v i a b l e a l t e r n a t i v e s 1. and t i n f i n a l p o s i t i o n , o n l y J makes a word , and t h e r e f o r e word i d e n t i f i c a t i o n ( l e x i c a l a c c e s s ) c a n b e . a c h i e v e d ( M a s s a r o , 1 9 7 7 ) . Each word i n t h e l e x i c o n c o n t a i n s b o t h p e r c e p t u a l and c o n c e p t u a l c o d e s . The word which is r e c o g n i z e d i s t h e o n e whose p e r c e p t u a l code g i v e s t h e b e s t ma tch and whose c o n c e p t u a l c o d e is mos t a p p r o p r i a t e i n t h a t p a r t i c u l a r c o n t e x t .

G e n e r a t e d a b s t r a c t memory c o r r e s p o n d s t o t h e s h o r t - t e r m o r working memory o f mos t i n f o r m a t i o n p r o c e s s i n g mode l s . I n o u r m o d e l , t h i s memory i s common t o b o t h s p e e c h p e r c e p t i o n and r e a d i n g . Recoding and r e h e a r s a l p r o c e s s e s b u i l d and m a i n t a i n s e m a n t i c and s y n t a c t i c s t r u c t u r e s a t t h e l e v e l o f g e n e r a t e d a b s t r a c t memory. I t i s a l s o p o s s i b l e t o g o from meaning t o a v i s u a l o r a u d i t o r y p e r c e p t i n o u r mode l . The r e c o d i n g o p e r a t i o n c a n t r a n s f o r m t h e meaning o f a c o n c e p t i n t o i ts s u r f a c e s t r u c t u r e i n a n a u d i t o r y o r v i s u a l fo rm.

Two i s sues c o n c e r n i n g l e t t e r and word r e c o g n i t i o n i n r e a d i n g w i l l b e a d d r e s s e d i n t h e p r e s e n t r e s e a r c h . F i r s t , wha t a r e t h e v i s u a l f e a t u r e s o f l e t t e r s u t i l i z e d by t h e p r i m a r y r e c o g n i t i o n p r o c e s s ? Second , how is knowledge o f o r t h o g r a p h i c s t r u c t u r e p s y c h o l o g i c a l l y r e p r e s e n t e d ? To a d d r e s s t h e s e i s s u e s , a n y s t u d y m u s t b e c o n c e r n e d w i t h how t h e s e s o u r c e s o f i n f o r m a t i o n a r e e v a l u a t e d , i n t e g r a t e d , and combined i n p e r c e p t u a l r e c o g n i t i o n ( M a s s a r o , 1 9 7 9 b ) . The d i s c u s s i o n o f v i s u a l f e a t u r e s i s p r e s e n t e d i n C h a p t e r 2 and t h e d i s c u s s i o n o f o r t h o g r a p h i c s t r u c t u r e is p r e s e n t e d i n C h a p t e r 3 . The f o u r t h c h a p t e r f o c u s e s on how t h e r e a d e r u t i l i z e s b o t h s o u r c e s o f i n f o r m a t i o n i n a v a r i e t y o f p e r c e p t u a l r e c o g n i t i o n and o v e r t


j udgmen t t asks . T o s u s t a i n t h e l o g i c a l c o n t i n u i t y of t h e p r e s e n t a t i o n o f t h e e x p e r i m e n t s , d e t a i l s o f t h e m e t h o d , p r o c e d u r e , and r e s u l t s a r e p l a c e d i n a p p e n d i c e s a t t h e end of t h e c h a p t e r . The f i f t h c h a p t e r p r e s e n t s a d e t a i l e d e v a l u a t i o n Of t h e p s y c h o l o g i c a l r e a l i t y o f many d e s c r i p t i o n s of o r t h o g r a p h i c s t r u c t u r e . The d a t a b a s e d e r i v e d from t h e p r e s e n t e x p e r i m e n t s is a l s o p r e s e n t e d t o a l l o w a d d i t i o n a l tests o f o t h e r d e s c r i p t i o n s of o r t h o g r a p h i c s t r u c t u r e . I n a d d i t i o n , n o r m a t i v e c o u n t s o f l e t t e r and l e t t e r c l u s t e r o c c u r r e n c e s i n t e x t a r e p r e s e n t e d . T h e s e c o u n t s m a k e p o s s i b l e t h e measu remen t o f a v a r i e t y of s t i m u l u s and t e s t i t ems a c c o r d i n g t o a number o f f o r m a l d e s c r i p t i o n s o f o r t h o g r a p h i c s t r u c t u r e . The l a s t c h a p t e r s u m m a r i z e s t h e c o n t r i b u t i o n s of t h e p r e s e n t r e s e a r c h . The c e n t r a l c o n c e r n o f t h e e m p i r i c a l and t h e o r e t i c a l work p r e s e n t e d h e r e is t o e v a l u a t e t h e n a t u r e of t h e p r o c e s s e s i n v o l v e d i n l e t t e r and word r e c o g n i t i o n and t o d i s c o v e r how knowledge a b o u t o r t h o g r a p h i c s t r u c t u r e is r e p r e s e n t e d and u t i l i z e d .

2 Visual Information

Most of t h e t r a d i t i o n a l r e s e a r c h r e l e v a n t t o v i s u a l i n f o r m a t i o n i n r e a d i n g h a s been concerned w i t h t h e l e g i b i l i t y of v a r i o u s t y p e f o n t s and t e x t f o r m a t s . Spencer (1969) summarizes t h i s work i n an a d e q u a t e and i n t e r e s t i n g manner and w e w i l l n o t a t t e m p t t o d u p l i c a t e a d e t a i l e d c o v e r a g e h e r e . A f t e r ment ioning a few g e n e r a l p r i n c i p l e s of t h e l e g i b i l i t y of p r i n t e d t e x t , we w i l l p r o v i d e some d i s c u s s i o n of t h e r o l e of f e a t u r e t h e o r i e s i n d e s c r i b i n g how l e t t e r s a r e r e c o g n i z e d . F i n a l l y , we w i l l e v a l u a t e t h e f u n c t i o n a l p r o p e r t i e s of t h e t y p e f o n t s used i n our e x p e r i m e n t s s i n c e t h i s i n f o r m a t i o n w i l l be n e c e s s a r y i n our s t u d i e s of how v i s u a l i n f o r m a t i o n and o r t h o g r a p h i c s t r u c t u r e c o n t r i b u t e t o p e r c e p t u a l r e c o g n i t i o n .

EARLY WORK

Much of t h e e a r l y work r e v e a l e d t h a t l e t t e r s a r e n o t e q u a l l y l e g i b l e . Table 2 . 1 p r e s e n t s t h e rank o r d e r of t h e l e g i b i l i t y of t h e l o w e r c a s e l e t t e r s i n an exper iment by C a t t e l l i n 1885 ( c i t e d i n Anderson & Dearborn , 1952) and an e x p e r i m e n t i n our l a b o r a t o r y some 90 y e a r s l a t e r . Except f o r a few of t h e l e t t e r s s u c h a s 9, 5 , and 1, t h e r e is an i m p r e s s i v e agreement between t h e two s t u d i e s . Both s t u d i e s found t h a t some of t h e most f r e q u e n t l e t t e r s a r e t h e l e a s t l e g i b l e . The h i g h l y f r e q u e n t x-he ight l e t t e r s a , c , e , 0 , and 2 were p o o r l y recognized i n both s t u d i e s . The s i m i l a r s i z e and o v e r a l l shape of t h e s e l e t t e r s c a u s e them t o be c o n f u s a b l e and , t h e r e f o r e , p o o r l y l e g i b l e . C a t t e l l ' s r e s e a r c h ( 1 8 8 5 ) , as w e l l a s more

1 2 CHAPTER 2

Table 2 . 1 Rank o r d e r of d i s t i n c t i v e n e s s of lowercase l e t t e r s a c c o r d i n g t o C a t t e l l (1885) and i n t h e p r e s e n t s t u d y .

L e t t e r a b

d e f 9 h i

k 1 m

C

1

C a t t e l l 19

6 25 1

2 2 1 7 2 4

5 23 11

2 1 0

3

P r e s e n t S tudy

2 2 1

19 9

23 1 8

4 6

26 20

7 1 5 11

L e t t e r n

P 4 r S

t

0

U

V

W

X

Y z

Ca t t e l l 18 1 6

I 4

1 5 2 6 1 2

9 1 3

8 2 0 2 1 1 4

P r e s e n t

1 7 2 4

2 8

1 2 2 5 2 1 1 4 1 6 1 0

3 5

1 3

Study

r e c e n t s t u d i e s by Bouma (1971) and o u r s e l v e s , found t h a t t h e s l i m l e t t e r s g, &, 1, I, r , and t were s i m i l a r l y confused f o r one a n o t h e r l e a d i n g t o r e l a t i v e l y poor r e c o g n i t i o n . F i n a l l y , C a t t e l l observed t h a t l e g i b i l i t y i s h i g h l y c o r r e l a t e d w i t h o v e r a l l l e t t e r s i z e ; contemporary s t u d i e s a l s o s u p p o r t t h i s o b s e r v a t i o n .

Tinker (1965) a l s o noted agreement among s t u d i e s of l e t t e r l e g i b i l i t y . H e r e p o r t e d c o r r e l a t i o n s between .48 and .88 a c r o s s s t u d i e s u s i n g , q v a r i e t y of measurement t e c h n i q u e s and t y p e f a c e s . For i n s t a n c e , t h e l e t t e r s 4, m, 2 , g , and w were c o n s i s t e n t l y found t o be h i g h l y l e g i b l e whereas c , e , I, 1, and - n were p o o r l y l e g i b l e . T inker concluded t h a t o v e r a l l s i z e , s i m p l i c i t y of o u t l i n e , and t h e amount of w h i t e s p a c e e n c l o s e d by a l e t t e r a r e i m p o r t a n t d e t e r m i n a n t s of l e g i b i l i t y . We w i l l p r o v i d e a more d e t a i l e d a n a l y s i s of l e t t e r l e g i b i l i t y and l e t t e r c o n f u s i o n s l a t e r i n t h i s c h a p t e r .

Another common o b s e r v a t i o n i n e a r l y r e s e a r c h was t h a t t e x t p r i n t e d i n uppercase l e t t e r s is inore d i f f i c u l t t o read t h a n i ts lowercase e q u i v a l e n t . Lowercase p r i n t may be more f a m i l i a r t h a n uppercase because of d i f f e r e n c e s i n f r e q u e n c y of o c c u r r e n c e . However, a s Spencer (1969) p o i n t s o u t , p r o p o r t i o n a t e l y - s p a c e d p r i n t e d t e x t i n c a p i t a l s o c c u p i e s a b o u t 5 0 % more s p a c e than it d o e s i n l o w e r c a s e . (Uppercase and

VISUAL INFORMATION I N R E A D I N G 1 3

l o w e r c a s e o c c u p y t h e same amount o f s p a c e i n t y p e w r i t t e n t e x t , a s i n t h e p r e s e n t m o n o g r a p h ) . The r e a d e r m u s t m a i n t a i n a l a r g e r s p a n o f a p p r e h e n s i o n i n t e r m s o f v i s u a l a n g l e i n o r d e r t o r e a d u p p e r c a s e t e x t a t t h e same r a t e a s l o w e r c a s e . G i v e n t h a t a c u i t y f a l l s o f f d r a m a t i c a l l y w i t h e x t e n t i n t o t h e p e r i p h e r a l v i s i o n , i t i s n o t s u r p r i s i n g t h a t l o w e r c a s e t e x t w i l l show a n a d v a n t a g e . I t would b e i n t e r e s t i n g t o compare upper- and l o w e r c a s e t e x t when t h e s i z e o f t h e l e t t e r s is a d j u s t e d t o e q u a t e f o r v i s u a l a n g l e . However, p e r f o r m a n c e may s t i l l be a t a d i s a d v a n t a g e w i t h u p p e r c a s e s i n c e on t h e a v e r a g e , t h e l a r g e r l e t t e r s w i l l b e c l o s e r t o g e t h e r and a l l o w f o r more l a t e r a l i n t e r f e r e n c e ( t h e m u t u a l d e g r a d a t i o n o f t h e p e r c e p t i b i l i t y o f a d j a c e n t l e t t e r s b e c a u s e o f t h e p r o x i m i t y o f t h e i r c o n t o u r s ) . The s i m p l e s t e x p l a n a t i o n is t h a t l o w e r c a s e l e t t e r s may b e s i m p l y more p e r c e p t i b l e t h a n u p p e r c a s e .

J a v a 1 ( c i t e d i n S p e n c e r , 1 9 6 9 ) showed t h a t r e a d i n g is much e a s i e r when t h e t o p h a l f , r a t h e r t h a n t h e b o t t o m h a l f , o f a l i n e o f words is e x p o s e d . I t is n o t c l e a r where t h e v e r t i c a l c e n t e r was d e f i n e d , b u t w e m i g h t assume t h a t i t was i n t h e m i d d l e o f a n x - h e i g h t l e t t e r . I t would b e v a l u a b l e t o d e f i n e t h e p e r c e p t u a l m i d d l e , i . e . , t h e p o i n t a t wh ich r e a d i n g t h e t o p and bo t tom p o r t i o n s o f a l i n e o f p r i n t is e q u a l l y e a s y . C o n s i s t e n t w i t h J a v a l ' s f i n d i n g s , Messmer ( c i t e d i n Huey, 1908 /1968) c o n c l u d e d t h a t a s c e n d i n g l e t t e r s ( e . g . , b, h) a r e " d o m i n a n t " and c o n t r i b u t e more t o word r e c o g n i t i o n t h a n x - h e i g h t ( e . g . , a , 5 ) or d e s c e n d i n g ( e . g . , g, E) l e t t e r s . Z e i t l e r ( c i t e d i n Woodworth, 1 9 3 8 ) a l s o found t h a t i n s h o r t p r e s e n t a t i o n s , a s c e n d i n g and d e s c e n d i n g l e t t e r s were more l i k e l y t o b e p e r c e i v e d ( a l s o see Huey, 1908 /1968 , pp . 7 9 - 8 7 ) . J a v a l ' s i d e a was t h a t a s c e n d i n g l e t t e r s a r e more e a s i l y p e r c e i v e d b e c a u s e t h e e y e t e n d s t o f i x a t e above t h e m i d d l e of t h e l i n e of p r i n t . Huey (1908 /1968 p . 99) r e j e c t e d t h i s p r o p o s a l by c i t i . i g some s t a t i s t i c s showing t h a t a s c e n d i n g l e t t e r s a r e much more f r e q u e n t t h a n d e s c e n d i n g l e t t e r s , and t h e r e f o r e , a word i s s i m p l y l i k e l y t o h a v e more i n f o r m a t i o n above t h a n be low t h e m i d d l e of a l i n e o f p r i n t .

FEATURE ANALYSIS

C o n s i s t e n t w i t h t h e t r a d i t i o n o f p s y c h o p h y s i c s , p s y c h o l o g i s t s h a v e been c o n c e r n e d w i t h t h e v i s u a l c h a r a c t e r i s t i c s o f t h e s t i m u l u s t h a t a r e f u n c t i o n a l i n l e t t e r and word p e r c e p t i o n . The g o a l o f t h i s work i s t o r e l a t e t h e p h y s i c a l f e a t u r e s o f l e t t e r s and words t o t h e i r p e r c e p t u a l

CHAPTER 2

r e c o g n i t i o n . The e a r l y workers i n t h i s a r e a i m p l i c i t l y assumed t h a t l e t t e r s were t h e s m a l l e s t u n i t s of v i s i b l e a n a l y s i s . I n t h i s view, l e t t e r s a r e i n d i v i s i b l e u n i t s t h a t can n o t be ana lyzed f u r t h e r t o p r o v i d e a d e s c r i p t i o n of t h e r e l a t i o n s h i p among d i f f e r e n t l e t t e r s . I n t o d a y ' s t e r m i n o l o g y , t h i s view would c o r r e s p o n d t o a t e m p l a t e v i e w of l e t t e r r e c o g n i t i o n . I d e a l l y , t h e r e a d e r would have a t e m p l a t e c o r r e s p o n d i n g t o e a c h of t h e l e t t e r s i n t h e language and p e r c e p t u a l r e c o g n i t i o n would i n v o l v e f i n d i n g t h e b e s t match between t h e v i s u a l i n f o r m a t i o n i n t h e l e t t e r and t h e t e m p l a t e i n memory.

Opposing t h e view of l e t t e r s a s i n d i v i s i b l e u n i t s is t h e i d e a of l e t t e r s having a number of d i s t i n c t i v e f e a t u r e s . T h i s i d e a was g e n e r a t e d by work on t h e l i n g u i s t i c d e s c r i p t i o n of speech sounds a b o u t 30 y e a r s ago (Jakobson, F a n t , & H a l l e , 1 9 6 1 ) . Many s t r u c t u r a l l i n g u i s t s a t t h a t t i m e t r e a t e d phonemes a s t h e s m a l l e s t u n i t s of speech . I f phoneme u n i t s a r e i n d i v i s i b l e , t h e n t h e p h y s i c a l o r p e r c e p t u a l r e l a t i o n s h i p between two phonemes is n o t of c e n t r a l i n t e r e s t . Jakobson e t a l . c h a l l e n g e d t h i s p o i n t of view by t r e a t i n g phonemes a s c o n s i s t i n g of a bundle of d i s t i n c t i v e f e a t u r e s . A r e l a t i v e l y s m a l l number of d i s t i n c t i v e f e a t u r e s c h a r a c t e r i z e d each phoneme of t h e language . As an example, Jakobson e t a l . (1961) were a b l e t o u s e j u s t n i n e f e a t u r e s t o d i s t i n g u i s h 28 phonemes i n E n g l i s h . The i d e a of d i s t i n c t i v e f e a t u r e a n a l y s i s a l s o proved p r o d u c t i v e i n d e v e l o p i n g p a t t e r n r e c o g n i t i o n by machine. S e l f r i d g e and N e i s s e r (1960) reviewed t e m p l a t e matching schemes and f e a t u r e a n a l y s i s schemes f o r t h e r e c o g n i t i o n of l e t t e r s . These developments i n l i n g u i s t i c s and a r t i f i c i a l i n t e l l i g e n c e i n f l u e n c e d t h e development of f e a t u r e models of t h e v i s i b l e c h a r a c t e r i s t i c s of l e t t e r s .

LETTER FEATURES

A v a l u a b l e t e c h n i q u e f o r t h e s t u d y of t h e v i s u a l f e a t u r e s of l e t t e r s i n v o l v e s t h e g e n e r a t i o n of c o n f u s i o n m a t r i c e s . A c o n f u s i o n m a t r i x i n d i c a t e s what l e t t e r s w i l l be seen a s o t h e r l e t t e r s when e r r o r s a r e made. To induce e r r o r s , e i t h e r t h e v i s u a l i n p u t from t h e l e t t e r m u s t be degraded o r t h e p r o c e s s i n g time a v a i l a b l e f o r r e c o g n i t i o n of t h a t l e t t e r m u s t be l i m i t e d . To d e g r a d e l e t t e r s , t h e y have been p r e s e n t e d a t r e l a t i v e l y l a r g e d i s t a n c e s o r i n p e r i p h e r a l v i s i o n . P r o c e s s i n g time is n o t l i m i t e d b u t f e a t u r a l i n f o r m a t i o n i s degraded . To l i m i t p r o c e s s i n g t i m e , l e t t e r s have been p r e s e n t e d f o r a s h o r t d u r a t i o n a t a good f igure-ground c o n t r a s t b u t c l o s e l y f o l l o w e d


by a masking s t i m u l u s t h a t s e r v e s t o h a l t p r o c e s s i n g . The assumpt ion i n l i m i t i n g p r o c e s s i n g t i m e is t h a t t h e r e a d e r m a k e s an e r r o r because of i n s u f f i c i e n t time t o p r o c e s s c o m p l e t e l y t h e f e a t u r a l i n f o r m a t i o n . Of c o u r s e , i t is i m p o r t a n t t o a n a l y z e c o n f u s i o n m a t r i c i e s g e n e r a t e d from both t h e s e methods and t o d e t e r m i n e whether t h e y g i v e s i m i l a r r e s u l t s .

P r i o r t o Bouma's (1971) s t u d y , most contemporary e x p e r i m e n t s s t u d i e d t h e c o n f u s i o n s of uppercase l e t t e r s ( e . g . , Gibson , O s s e r , S c h i f f , & Smith , 1963; Townsend, 1 9 7 1 ) . Bouma u t i l i z e d l o w e r c a s e l e t t e r s of t h e IBM C o u r i e r 1 0 t y p e f a c e shown i n F i g u r e 2 . 1 . Bouma p r e s e n t e d t h e l e t t e r s a t a r e l a t i v e l y l a r g e r e a d i n g d i s t a n c e i n one s t u d y and i n p e r i p h e r a l v i s i o n i n a n o t h e r . The c o n f u s i o n s were v e r y s y s t e m a t i c and a l lowed Bouma t o a s s i g n t h e l e t t e r s t o g r o u p s of l e t t e r s t h a t were c o n f u s a b l e w i t h i n a g r o u p b u t n o t among g r o u p s . The c o n f u s i o n s among l e t t e r s were p r i m a r i l y dependent upon o v e r a l l l e t t e r shape and s i z e . Many of t h e r e c o g n i t i o n c o n f u s i o n s c o u l d be d e s c r i b e d by j u s t t h r e e c l a s s e s of l e t t e r s : s h o r t o r x - h e i g h t l e t t e r s , a s c e n d i n g l e t t e r s ( a s c e n d e r s ) , and d e s c e n d i n g l e t t e r s ( d e s c e n d e r s ) . Given an x - h e i g h t l e t t e r , a r e c o g n i t i o n con- f u s i o n u s u a l l y r e s u l t e d from a n o t h e r x-he ight l e t t e r and s o on. The x - h e i g h t l e t t e r s and a s c e n d e r s c a n a l s o be broken down i n t o s m a l l e r g r o u p s a s i n d i c a t e d i n Table 2 . 2 . Bouma a r g u e s t h a t o v e r a l l l e t t e r shape is a n i m p o r t a n t d e t e r m i n a n t of r e c o g n i t i o n c o n f u s i o n s and i n t r o d u c e s t h e c o n c e p t of e n v e l o p e . The envelope of a l e t t e r i s t h e s m a l l e s t polygon s u r r o u n d i n g a l e t t e r w i t h o u t i n d e n t a t i o n . For example, t h e e n v e l o p e f o r c would be c i r c u l a r , whereas would be e n c l o s e d by a n i n v e r t e d

a c e m n

o r s u

v w x z

b d f h

i k l t

F i g u r e 2 . 1 Lowercase l e t t e r s of t h e IBM C o u r i e r 1 0 t y p e f a c e used by Bouma ( 1 9 7 1 ) .

16 CHAPTER 2

Table 2 . 2 The seven g r o u p s of c o n f u s a b l e l e t t e r s of t h e IBM C o u r i e r 1 0 t y p e f a c e ( a f t e r Bouma, 1 9 7 1 ) .

1. a s z x 2 . e o c 3. n m u 4 . r v u 5. d h k b 6 . t i l f 7 . g p j y q

t r i a n g l e . These e n v e l o p e s of l e t t e r s a c c o u n t f o r some of t h e c o n f u s i o n e r r o r s . A s an example, t h e g r o u p of c o n f u s a b l e l e t t e r s (a, 2 , z, z) have roughly r e c t a n g u l a r e n v e l o p e s w i t h inner p a r t s .

I n o r d e r t o p r o v i d e an independent a s s e s s m e n t of t h e f e a t u r a l i n f o r m a t i o n t h a t i s f u n c t i o n a l i n t h e r e c o g n i t i o n of lowercase l e t t e r s , we c a r r i e d o u t a l e t t e r r e c o g n i t i o n exper iment . F i g u r e 2 . 2 p r e s e n t s a photograph of t h e l e t t e r s a s t h e y appeared i n t h e e x p e r i m e n t . A s i n g l e l e t t e r was p r e s e n t e d on each t r i a l a t a r e l a t i v e l y dim i n t e n s i t y t o keep o v e r a l l

0123456789 : ; ?

ABCDEFGHIJKLMNO PQRSTUVWXYZ abcdefghijklmno

pqrstuvwxyz F i g u r e 2 . 2 The s e t of c h a r a c t e r s c u r r e n t l y be ing used i n our

l a b o r a t o r y . The c h a r a c t e r s a r e p l o t t e d a s p o i n t s on an o s c i l l o s c o p e and t h e a v e r a g e c h a r a c t e r is composed of approximate ly 35 p o i n t s .

VISUAL INFORMATION I N READING 17

a c c u r a c y a t a b o u t 5 0 % . The t e s t l e t t e r was p r e s e n t e d a t t h e f i x a t i o n p o i n t f o r a s h o r t d u r a t i o n and no masking s t i m u l u s was p r e s e n t e d . Three s u b j e c t s c o n t r i b u t e d a t o t a l of 296 o b s e r v a t i o n s f o r e a c h of t h e 26 l e t t e r s of t h e a l p h a b e t . T a b l e 2.3 p r e s e n t s t h e o v e r a l l a c c u r a c y f o r each o f t h e 26 l e t t e r s , t h e f a l s e a l a r m r a t e s , t h e d' v a l u e s , and c o n f u s i o n r e s p o n s e s t h a t o c c u r r e d more t h a n 5% of t h e t i m e t o a g i v e n tes t l e t t e r .

One p o s s i b l e l i m i t a t i o n w i t h t h e s e d a t a and o t h e r s t u d i e s o f t h i s n a t u r e i s t h a t t h e l e t t e r s d i f f e r i n o v e r a l l a c c u r a c y , and t h e r e f o r e , t h e r e is n o t an e q u a l o p p o r t u n i t y f o r c o n f u s i o n s f o r each of t h e l e t t e r s . On t h e o t h e r hand, i t might be a r g u e d t h a t t h e o v e r a l l a c c u r a c y of a g i v e n a l t e r n a t i v e may r e f l e c t how e a s i l y i t is confused w i t h o t h e r l e t t e r s . That is t o s a y , a l e t t e r c o m p l e t e l y d i s s i m i l a r from t h e o t h e r l e t t e r s would g i v e good per formance s i n c e i t w i l l n o t be confused f o r any of t h e a l t e r n a t i v e s . R e g a r d l e s s of which i n t e r p r e t a t i o n is more r e a s o n a b l e , i t might be wor thwhi le t o r e p e a t t h e e x p e r i m e n t w h i l e a d j u s t i n g t h e i n t e n s i t y i n d i v i d u a l l y f o r each l e t t e r t o keep i t s per formance a t 50% c o r r e c t .

The p e r c e n t a g e c o r r e c t i d e n t i f i c a t i o n f o r each of t h e 26 l e t t e r s of t h e a l p h a b e t i n T a b l e 2.3 shows t h a t r e c o g n i t i o n a c c u r a c y ranged w i d e l y . T h i s r e s u l t may r e p r e s e n t a v i s u a l e f f e c t O K a d e c i s i o n e f f e c t . Some l e t t e r s may p r o v i d e more v i s u a l f e a t u r a l i n f o r m a t i o n t h a n o t h e r l e t t e r s under t h e same s t i m u l u s c o n d i t i o n s . A l t e r n a t i v e l y , o b s e r v e r s may d e r i v e e q u i v a l e n t amounts of f e a t u r a l i n f o r m a t i o n from a l l l e t t e r s b u t may have d e c i s i o n b i a s e s i n t h e i n t e r p r e t a t i o n of t h e f e a t u r a l i n f o r m a t i o n . A s a n example, o b s e r v e r s might be b i a s e d t o i n t e r p r e t t h e f e a t u r a l i n f o r m a t i o n i n te rms of l e t t e r s t h a t occur more f r e q u e n t l y i n t h e language . The d e c i s i o n i n t e r p r e t a t i o n , however, a p p e a r s t o be i n c o n s i s t e n t w i t h t h e r e s u l t s . For example, t h e i n f r e q u e n t l e t t e r s 5 , y , and z averaged a b o u t 65% c o r r e c t , whereas t h e f r e q u e n t l e t t e r s e , g, - 0, and 2 averaged a b o u t 35% c o r r e c t . I n c o n t r a s t t o what would be e x p e c t e d from a f r e q u e n c y b i a s , t h e s e l e a s t f r e q u e n t l e t t e r s a r e r e c o g n i z e d much b e t t e r t h a n t h e more f r e q u e n t l e t t e r s . T h i s a n a l y s i s p r o v i d e s s u p p o r t f o r t h e i d e a t h a t d i f f e r e n c e s i n a c c u r a c y a r e due t o d i f f e r e n c e s i n t h e f e a t u r a l i n f o r m a t i o n of t h e l e t t e r s . A more d i r e c t measure of v i s u a l r e s o l u t i o n i s t o take a 4' measure a s proposed by t h e t h e o r y of s i g n a l d e t e c t a b i l i t y (Green & Swets , 1966; Massaro &

Schmuller , . 1 9 7 5 ) . Table 2.3 shows t h a t t h e s e d' v a l u e s c o r r e l a t e r a t h e r h i g h l y w i t h t h e p e r c e n t a g e c o r r e c t v a l u e s . Given t h e assumpt ion t h a t t h e d' v a l u e s a r e n o t i n f l u e n c e d by any d i f f e r e n c e s i n d e c i s i o n b i a s e s , t h e r e s u l t s

1 8 CHAPTER 2

T a b l e 2 .3 P r o p o r t i o n o f times a l e t t e r was r e c o g n i z e d c o r r e c t l y ( H i t ) a n d was g i v e n as a n i n c o r r e c t r e s p o n s e t o o t h e r l e t t e r s ( F a l s e A l a r m ) ; t h e d'

a l u e ; a n d t h e c o n f u s i o n r e s p o n s e s g r e a t e r t h a n 5 % ( f r o m p r e s e n t s t u d y ) .

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. 0 1 6 , 0 1 0 . 0 2 3 .010 .0 20 . 0 1 0 . 0 1 5 . 0 1 0 . 0 1 0 . 0 1 5 . 0 1 0

1 . 8 5 2 . 7 2 2 .05 2 .64 1 . 7 9 1 . 9 4 2 . 5 6 2 .46 1 . 4 2 1 . 9 2 2 . 6 1 2 .10 2 .66 2 .24 1 . 7 8 2 .78 2 . 7 1 2 .24 1 . 8 7 1 . 7 6 2 .46 2 .16 2 .66 2 .94 2 .67 2 . 5 1

l o c a t e t h e d i f f e r e n c e s i n l e t t e r r e c o g n i t i o n a t a v i s u a l s t a g e o f p r o c e s s i n g .

T a b l e 2 .3 a l s o p r o v i d e s a n i n d e x o f t h e l e t t e r s w h i c h a re c o n f u s e d w i t h o t h e r l e t t e r s i n t h e t a s k . F o r e a c h l e t t e r , a l l c o n f u s i o n s g i v e n f o r t h a t l e t t e r g r e a t e r t h a n 5% o f t h e t i m e a r e p r e s e n t e d . As a n e x a m p l e , g i v e n t h e s t i m u l u s a, s u b j e c t s r e s p o n d e d 1 4 % o f t h e time w i t h t h e a l t e r n a t i v e g a n d 7 % o f t h e time w i t h a l t e r n a t i v e g. T h i s means t h a t t h e l e t t e r a is o f t e n


i n t e r p r e t e d a s e . The c o n f u s i o n s a p p e a r t o b e r e l a t i v e l y s y s t e m a t i c and t h e r e f o r e s u g g e s t wh ich f e a t u r e s a r e f u n c t i o n a l i n l e t t e r r e c o g n i t i o n . T a b l e 2 . 4 p r o v i d e s a n a l o g o u s d a t a f rom t h e p e r i p h e r a l - v i e w i n g e x p e r i m e n t c a r r i e d o u t by Bouma on t h e I B M C o u r i e r 1 0 t y p e f a c e . The c o n f u s i o n s w i l l b e u t i l i z e d i n o u r l a t e r work when t h e r e l a t i v e s i m i l a r i t y b e t w e e n l e t t e r s becomes a n i m p o r t a n t q u e s t i o n i n o u r e x p e r i m e n t s .

The l e t t e r c o n f u s i o n s s u g g e s t t h a t o v e r a l l l e t t e r s h a p e i n f o r m a t i o n may b e o b t a i n e d b e f o r e c o m p l e t e l e t t e r p e r c e p t i o n ( r e s o l u t i o n ) . For example , 48% o f t h e e r r o r r e s p o n s e s t o t h e s t i m u l u s 2 were e and 0; t h i s i n d i c a t e s t h a t s u b j e c t s s aw a c i r c u l a r s h a p e on many o f t h e t r i a l s b u t d i d n o t know w h e t h e r t h e l e t t e r was 2 , e , o r 0. T h i s r e s u l t m i g h t b e i n t e r p r e t e d t o mean t h a t t h e o v e r a l l e n v e l o p e o f a l e t t e r is r e s o l v e d b e f o r e d e t a i l s o f i t s component f e a t u r e s . I n d e p e n d e n t l y o f w h e t h e r t h e whole is g r e a t e r t h a n t h e sum o f i t s p a r t s , a g e n e r a l i m p r e s s i o n o f t h e who le ( a l t h o u g h ambiguous ) i s s e e n b e f o r e a l l o f t h e p a r t s . T h a t a l e t t e r ' s e n v e l o p e ( n o pun i n t e n d e d ) becomes a v a i l a b l e b e f o r e i t s d e t a i l s i s a l s o c o n s i s t e n t w i t h f o u r i e r - a n a l y s i s s t u d i e s . T h e r e is e v i d e n c e t h a t i n f o r m a t i o n g i v e n by l o w s p a t i a l f r e q u e n c i e s i s p r o c e s s e d f a s t e r t h a n h i g h s p a t i a l f r e q u e n c y i n f o r m a t i o n ( B r e i t m e y e r & Ganz , 1976 ; B r o a d b e n t , 1 9 7 7 ) . A c c o r d i n g l y , l ow s p a t i a l f r e q u e n c i e s p r o v i d e i n f o r m a t i o n a b o u t o v e r a l l s h a p e w h e r e a s h i g h f r e q u e n c y i n f o r m a t i o n r e d u c e s u n c e r t a i n t y a b o u t l e t t e r d e t a i l . E i t h e r l i m i t e d p r o c e s s i n g time o r a r e d u c e d f i g u r e - g r o u n d c o n t r a s t c o u l d a l l o w e n v e l o p e r e s o l u t i o n w i t h o u t c o r r e s p o n d i n g r e s o l u t i o n o f l e t t e r d e t a i l . I n terms o f t h e p r e s e n t a n a l y s i s , t h e r e a d e r w i l l have t o d e c i d e wh ich l e t t e r b e s t f i t s t h e p e r c e i v e d b u t f u z z y e n v e l o p e . For e x a m p l e , r e c o g n i t i o n o f a c i r c u l a r e n v e l o p e w i t h o u t f u r t h e r d e t a i l would b e s u f f i c i e n t t o l i m i t t h e a l t e r n a t i v e s t o t h e t h r e e l e t t e r s 2 , g , a n d 0.

G i v e n t h a t o u r p r i m a r y m o t i v a t i o n is t o s t u d y t h e i n t e r a c t i o n o f l o w e r - l e v e l v i s u a l i n f o r m a t i o n w i t h h i g h e r - o r d e r knowledge i n l e t t e r r e c o g n i t i o n , we a r e n o t d i r e c t l y c o n c e r n e d w i t h which l e t t e r f e a t u r e s a r e u t i l i z e d i n p e r c e p t u a l r e c o g n i t i o n . T h e r e a r e now s u f f i c i e n t d a t a c o n s i s t e n t w i t h t h e i d e a t h a t l e t t e r r e c o g n i t i o n is m e d i a t e d by f e a t u r e s ( M a s s a r o &

S c h m u l l e r , 1 9 7 5 ) . F e a t u r e s a r e n o t l i m i t e d t o s m a l l component p r o p e r t i e s b u t c a n b e r e l a t i v e l y complex r e l a t i o n a l p r o p e r t i e s s u c h a s t h e o v e r a l l c i r c u l a r e n v e l o p e o f t h e l e t t e r s 5, g , a n d - 0. A d d i t i o n a l l y , i n c o n t r a s t t o t h e common a s s u m p t i o n t h a t f e a t u r e s a r e d e t e c t e d i n a n a l l - o r - n o n e m a n n e r , w e p r e f e r t o v i e w t h e f e a t u r e d e t e c t i o n p r o c e s s a s c o n t i n u o u s . V i s i b l e f e a t u r e s may b e f u z z y s o t h a t r e c o g n i t i o n c o n s i s t s o f

20 CHAPTER 2

T a b l e 2 .4 P r o p o r t i o n of times a l e t t e r was r e c o g n i z e d c o r r e c t l y ( H i t ) a n d was g i v e n a s an i n c o r r e c t r e s p o n s e t o o t h e r l e t t e r s ( F a l s e Alarm) ; t h e c o r r e s p o n d i n g d' v a l u e ; a n d t h e c o n f u s i o n r e s p o n s e s g r e a t e r t h a n 5% ( f r o m Bouma, 1 9 7 1 ) .

Let ter H i t F a l s e Alarm d' C o n f u s i o n s Greater t h a n 5%

a b

d e f g h i j k 1 m n

P 9 r

t

C

0

S

U

V

W

X

Y Z

. 6 2 0 . 0 5 3

. 6 2 0 . 0 2 4

. 1 9 0 . 0 0 6

. 8 3 0 . 0 1 9

. 3 4 0 . 0 4 5

. 8 1 0 . 0 1 3

. 3 1 0 . 0 1 8

. 8 0 0 . 0 2 8

. 6 9 0 . 0 3 5

. 8 2 0 .008

. 5 1 0 . 0 0 8

. 2 6 0 .007

. 7 9 0 . 0 2 8

. 5 6 0 . 0 2 6

. 5 7 0 . 0 1 7

. 8 4 0 . 0 1 7

. 7 4 0 . 0 1 9

. 5 5 0 . 0 1 5

. 1 0 0 . 0 0 9

. 5 9 0 . 0 1 3 . 5 6 0 .018 . 7 2 0 .016 . 7 0 0 . 0 1 4 . 3 2 0 . 0 0 3 . 5 7 0 . 0 0 3 . 1 2 0 .004

1 . 9 3 2 . 2 9 1 . 6 2 3 . 0 3 1 . 2 9 3 . 1 1 1 . 6 0 2 . 7 6 2 . 3 1 3 . 3 3 2 . 4 6 1 . 8 1 2 .72 2 . 1 0 2 . 3 0 3 . 1 2 2 . 7 1 2 . 3 1 1 . 0 8 2 .46 2 . 2 6 2 . 7 3 2 . 7 3 2 . 2 5 2 . 9 5 1 . 4 6

VISUAL INFORMATION I N READING 2 1

a s c e r t a i n i n g t h e d e g r e e t o which t h a t f e a t u r e is p r e s e n t o r a b s e n t i n t h e s t i m u l u s . Oden and Massaro (1978) have developed a model of speech p e r c e p t i o n based on t h e i d e a of c o n t i n u o u s a c o u s t i c f e a t u r e s . A s i m i l a r a n a l y s i s would seem t o be a v a l u a b l e c o n t r i b u t i o n i n l e t t e r r e c o g n i t i o n , a l t h o u g h beyond t h e scope of t h e p r e s e n t r e s e a r c h . For i n t e r e s t e d r e a d e r s , Oden (1979) i n i t i a t e d a n e m p i r i c a l and t h e o r e t i c a l s t u d y of f u z z y f e a t u r a l i n f o r m a t i o n i n l e t t e r s , and Massaro (1979a) q u a n t i f i e d a model t o a c c o u n t f o r how c o n t i n u o u s f e a t u r a l i n f o r m a t i o n of a l e t t e r is i n t e g r a t e d w i t h o r t h o g r a p h i c c o n t e x t i n l e t t e r r e c o g n i t i o n .

3 Orthographic Structure

I n t h i s c h a p t e r we d e s c r i b e t h e fundamenta l p r o p e r t i e s of o r t h o g r a p h i c s t r u c t u r e and s p e c u l a t e on how t h e s e p r o p e r t i e s might f a c i l i t a t e l e t t e r and word r e c o g n i t i o n . The g o a l of t h i s d i s c u s s i o n is t o d e r i v e d i f f e r e n t m e t r i c s f o r s c a l i n g t h e o r t h o g r a p h i c s t r u c t u r e of l e t t e r s t r i n g s based upon d i f f e r e n t assumpt ions a b o u t how o r t h o g r a p h i c s t r u c t u r e c o n t r i b u t e s t o r e c o g n i t i o n p r o c e s s e s . The e x p e r i m e n t s p r e s e n t e d i n Chapter 4 a t t e m p t t o e v a l u a t e t h e p s y c h o l o g i c a l r e a l i t y of s e v e r a l of t h e s e measures .

C e n t r a l t o t h e d i s c u s s i o n of t h i s c h a p t e r i s t h e assumpt ion t h a t s k i l l e d r e a d e r s d e r i v e i n f o r m a t i o n a b o u t l e g a l o c c u r r e n c e s of l e t t e r s o r l e t t e r s e q u e n c e s from r e p e a t e d e x p o s u r e s t o p r i n t e d words and t h a t t h e y employ t h i s i n f o r m a t i o n t o f a c i l i t a t e word r e c o g n i t i o n i n normal r e a d i n g t a s k s . Our concern h e r e is w i t h both t h e d e s c r i p t i o n of t h e a b s t r a c t e d i n f o r m a t i o n and i ts u t i l i z a t i o n i n t h e r e c o g n i t i o n p r o c e s s . I n t h e d i s c u s s i o n which f o l l o w s w e c o n c e n t r a t e on two broad c a t e g o r i e s of o r t h o g r a p h i c s t r u c t u r e : s t a t i s t i c a l redundancy and ru le -governed r e g u l a r i t y . S t a t i s t i c a l redundancy a p p l i e s t o t h o s e measures which can be d e r i v e d s o l e l y from t h e f r e q u e n c y w i t h which l e t t e r s , l e t t e r s e q u e n c e s , and words occur i n n a t u r a l t e x t s . Such measures might be based upon t y p e o r t o k e n c o u n t s . The measures might a p p l y t o l e t t e r s , l e t t e r s e q u e n c e s , o r t o any c l a s s i f i c a t i o n of t h e s e e n t i t i e s ( e . g . , vowel, c o n s o n a n t ) . Rule-governed r e g u l a r i t y a p p l i e s t o t h o s e p r o p e r t i e s o f l e t t e r s and l e t t e r s e q u e n c e s which can be g e n e r a l i z e d from e i t h e r t h e p h o n o l o g i c a l c o n s t r a i n t s of E n g l i s h words o r t h e s c r i b a l c o n v e n t i o n s . The l a t t e r c o n t r o l t h e s e l e c t i o n of l e t t e r s f o r e i t h e r r e p r e s e n t i n g sounds o r marking graphemic , g r a p h o t a c t i c , o r morphologica l

24 CHAPTER 3

func t io : i s . Rule-governed r e g u l a r i t y u s u a l l y s p e c i f i e s a l e t t e r s t r i n g a s r e g u l a r o r i r r e g u l a r . I n a d d i t i o n , th rough t h e s p e c i f i c a t i o n of r u l e s f o r g e n e r a t i n g l e g a l ( i . e . , E n g l i s h - l i k e ) l e t t e r s t r i n g s , l e v e l s of r e g u l a r i t y c a n be d e f i n e d .

STATISTICAL REDUNDANCY

Ordered a p p r o x i m a t i o n s t o E n g l i s h , based on a l g o r i t h m s proposed by Shannon ( 1 9 4 8 ) , were t h e f i r s t d e s c r i p t i o n s of o r t h o g r a p h i c s t r u c t u r e u t i l i z e d by p s y c h o l o g i s t s . Shannon (1948) c r e a t e d a zero-order approximat ion t o E n g l i s h by drawing l e t t e r s w i t h rep lacement from a p o o l of 27 unweighted symbols--the 26 l e t t e r s of t h e a l p h a b e t p l u s a s p a c e . ( I n t h i s a s i n most o t h e r s e q u e n t i a l g e n e r a t i o n t e c h n i q u e s , a n i n i t i a l s p a c e symbol is assumed.) I f t h i s same p r o c e d u r e is employed w i t h symbols t h a t a r e weighted a c c o r d i n g t o t h e i r f r e q u e n c i e s of o c c u r r e n c e i n t e x t s , f i r s t - o r d e r a p p r o x i m a t i o n s r e s u l t .

An n-g o r d e r approximat ion is produced by f i r s t s e l e c t i n g a l e t t e r s t r i n g of l e n g t h n-1. T h i s forms t h e beginning p a r t of t h e new s t r i n g . The t e x t is t h e n scanned f o r t h e f i r s t o c c u r r e n c e of t h i s i n i t i a l s t r i n g . When found, t h e n e x t l e t t e r a f t e r t h e l e t t e r s t r i n g sequence is added t o t h e s t r i n g b e i n g g e n e r a t e d , and a n e w s e a r c h s t r i n g i s c o n s t r u c t e d by d r o p p i n g t h e f i r s t l e t t e r of t h e l a s t s e a r c h s t r i n g and adding t h e l e t t e r j u s t l o c a t e d . T h i s p r o c e d u r e is t h e n r e p e a t e d u n t i l a space o c c u r s o r a d e s i r e d l e n g t h reached . M i l l e r , B r u n e r , and Postman (1954) used t h i s t e c h n i q u e t o g e n e r a t e e i g h t - l e t t e r pseudowords f o r a f u l l - r e p o r t t a s k . T h e i r f o u r t h - o r d e r approximat ions i n c l u d e d items l i k e m o s s i a n t , o n e t i c u l , p r e v e r a l , and f a v o r i a l , a l l q u i t e E n g l i s h - l i k e . Wallach ( 1 9 6 3 ) , on t h e o t h e r hand, t r u n c a t e d two l e t t e r s from each s t r i n g used by Miller e t a l . t h u s o c c a s i o n a l l y p r o d u c i n g a non-English s p e l l i n g ( e . g . , moss ia , l o r i a i ) . Although M i l l e r e t a l . (1954) were p r i m a r i l y concerned w i t h i n f o r m a t i o n t h e o r y , l a t e r e x p e r i m e n t e r s ( e . g . , L e f t o n , S p r a g i n s , & Byrnes, 1973; Mewhort & B e a l , 1977) have advoca ted o r d e r e d a p p r o x i m a t i o n s a s p s y c h o l o g i c a l l y r e l e v a n t d e s c r i p t i o n s of o r t h o g r a p h i c s t r u c t u r e .

A major shor tcoming of o r d e r e d a p p r o x i m a t i o n d e s c r i p t i o n s i s t h e i r i n a b i l i t y t o c o n t r o l s t r u c t u r a l v a r i a t i o n s w i t h i n approximat ion l e v e l s . Although any l a r g e g r o u p of s t i m u l i g e n e r a t e d by t h i s t e c h n i q u e w i l l approximate t h e f r e q u e n c i e s of o c c u r r e n c e of E n g l i s h l e t t e r s e q u e n c e s , t h e r e is no m e t r i c

ORTHOGRAPHIC STRUCTURE 25

i n c o r p o r a t e d i n t o t h e method f o r a s s e s s i n g t h e r e l a t i v e d e g r e e o f o r t h o g r a p h i c s t r u c t u r e o f s t r i n g s w i t h i n o r d e r c l a s s e s . I n G i l m o r e and E g e t h ( 1 9 7 6 ) , f o r e x a m p l e , z e r o - o r d e r a p p r o x i m a t i o n s t o E n g l i s h w e r e used t o g e n e r a t e wha t t h e a u t h o r s i n t e n d e d t o b e nonwords , wh ich t h e y c o n t r a s t e d w i t h r e a l E n g l i s h words . I f n o o t h e r c r i t e r i a were used t o e v a l u a t e t h e 30 s t r i n g s g e n e r a t e d f o r u s e i n t h e i r e x p e r i m e n t s , t h e r e was a 1 8 % c h a n c e t h a t a t l e a s t o n e r e a l word o c c u r r e d ( b a s e d on t h e a s s u m p t i o n o f 1 , 5 0 0 common f o u r - l e t t e r words i n E n g l i s h ) ; t h e p r o b a b i l i t y t h a t p seudowords o c c u r r e d was c o n s i d e r a b l y h i g h e r .

A s e c o n d s h o r t c o m i n g o f a s t r i c t p s y c h o l o g i c a l a p p l i c a t i o n of t h i s a p p r o a c h i s i t s s t r i c t r e l i a n c e on l e f t - t o - r i g h t g e n e r a t i o n o f l e t t e r s d u r i n g word r e c o g n i t i o n . For e x a m p l e , g i v e n th- and th-ugh a s p a r t i a l l y p e r c e i v e d s i x - l e t t e r s t r i n g s , t h e p r o b a b i l i t i e s o f i d e n t i f y i n g t h e t h i r d l e t t e r i n e a c h would b e t h e same i n t h a t o n l y i n f o r m a t i o n t o t h e l e f t b u t n o t t o t h e r i g h t o f a n y l e t t e r p o s i t i o n i s r e l e v a n t .

To overcome t h e s e d i f f i c u l t i e s , summed b i g r a m and t r i g r a m c o u n t s h a v e been p r o p o s e d a s metr ics . Underwood and S c h u l z ( 1 9 6 8 ) t a b u l a t e d t h e b i g r a m s and t r i g r a m s i n 2 ,090 w o r d s sampled f rom T h o r n d i k e and L o r g e ( 1 9 4 4 ) . S i n c e e a c h s a m p l e word was w e i g h t e d by i t s f r e q u e n c y o f o c c u r r e n c e i n t e x t s , t o k e n - b a s e d b i g r a m and t r i g r a m c o u n t s r e s u l t e d . By summing t h e f r e q u e n c i e s o f a l l t h e b i g r a m s o r t r i g r a m s w i t h i n a l e t t e r s t r i n g , a f a m i l i a r i t y i n d e x c a n b e d e r i v e d . Such a p r o c e d u r e was used by A n i s f e l d ( 1 9 6 4 ) , f o r e x a m p l e , i n r e a n a l y z i n g t h e G i b s o n , P i c k , Osser, and Hammond ( 1 9 6 2 ) s t u d y o f a f u l l r e p o r t o f v i s u a l l y - p r e s e n t e d l e t t e r s t r i n g s v a r y i n g i n p r o n o u n c e a b i l i t y . A c c o r d i n g t o A n i s f e l d ( 1 9 6 4 ) , t h e G i b s o n e t a l . r e s u l t s c o u l d b e a c c o u n t e d f o r a s e a s i l y by d i f f e r e n c e s i n summed b i g r a m c o u n t s a s t h e y c o u l d by t h e s p e l l i n g - t o - s o u n d u n i t s a d v o c a t e d by G i b s o n e t a l . G i b s o n ( 1 9 6 4 ) , i n a r e p l y t o A n i s f e l d ( 1 9 6 4 1 , however , showed t h a t c o r r e l a t i o n s o f summed b i g r a m and summed t r i g r a m c o u n t s w i t h s u b j e c t r e s p o n s e s were low and n o n s i g n i f i c a n t . I n a d d i t i o n , G i b s o n , S h u r c l i f f , and Yonas ( 1 9 7 0 ) found n e i t h e r summed b i g r a m n o r summed t r i g r a m c o u n t s t o b e a n a d e q u a t e p r e d i c t o r o f r e c o g n i t i o n s c o r e s f o r u n p r o n o u n c e a b l e and p r o n o u n c e a b l e l e t t e r s t r i n g s .

G i b s o n e t a l . ( 1 9 7 0 ) d i d n o t p r o v i d e a f a i r t e s t o f t h e f r e q u e n c y m e a s u r e s , however , b e c a u s e t h e c o u n t s were n o t a d j u s t e d f o r word l e n g t h i n a n y r e a s o n a b l e manner . Word l e n g t h a l o n e a c c o u n t e d f o r a b o u t 70% of t h e v a r i a n c e i n t h e r e c a l l s c o r e s ; t h e number o f e r r o r s n a t u r a l l y i n c r e a s e d w i t h i n c r e a s e s i n t h e l e n g t h o f t h e l e t t e r s t r i n g . The s i g n i f i c a n t

26 CHAPTER 3

c o r r e l a t i o n of p r o n o u n c e a b i l i t y could be due t o t h e s i m p l e f a c t t h a t s h o r t e r words a r e more pronounceable t h a n l o n g e r words. Suppor t ing t h i s i n t e r p r e t a t i o n , Spreen and S c h u l z (1966) found a n e g a t i v e c o r r e l a t i o n of . 8 3 between word l e n g t h and p r o n o u n c e a b i l i t y f o r 329 common nouns. T h e r e f o r e , t h e r e s u l t s of Gibson e t a l . (1962, 1970) r e a l l y d o n o t speak t o t h e issue of p r o n o u n c e a b i l i t y v e r s u s o r t h o g r a p h i c s t r u c t u r e of l e t t e r s t r i n g s when s t r i n g l e n g t h is h e l d c o n s t a n t .

The Underwood and Schulz (1960) t a b l e s p r o v i d e a means f o r d i f f e r e n t i a t i n g f a m i l i a r and u n f a m i l i a r s t r i n g s w i t h i n approximat ion c l a s s e s , b u t s u f f e r from l a c k of a t t e n t i o n t o word l e n g t h o r p o s i t i o n of l e t t e r s w i t h i n a word. A common s u f f i x l i k e -& would h e a v i l y weight a t r i g r a m c o u n t f o r a pseudoword whether i n i n i t i a l o r f i n a l p o s i t i o n a c c o r d i n g t o t h e s e t a b l e s , y e t i n E n g l i s h words t h i s sequence never o c c u r s i n i t i a l l y . I f l e t t e r p o s i t i o n w i t h i n a word i s a p s y c h o l o g i c a l l y r e l e v a n t v a r i a b l e , t h e Underwood and S c h u l z (1960) t a b l e s could n o t be used f o r e x p l o r i n g t h i s f a c t o r .

T h i s shor tcoming h a s been overcome, however, i n t h e Mayzner and T r e s s e l t (1965) and Mayzner, T r e s s e l t , and Wolin (1965a, 1965b) t a b l e s , which g i v e b igram, t r i g r a m , and t e t r a g r a m c o u n t s by word p o s i t i o n and by word l e n g t h f o r words from t h r e e t o seven c h a r a c t e r s i n l e n g t h . Mayzner and T r e s s e l t (1965) a l s o g i v e s i n g l e - l e t t e r p o s i t i o n a l f r e q u e n c i e s , which have been used by Mason (1975) t o e x p l o r e d i f f e r e n c e s between good and poor r e a d e r s i n a r e c o g n i t i o n t a s k . Although Mason (1975) confounds ru le -governed o r t h o g r a p h i c s t r u c t u r e w i t h p o s i t i o n a l f r e q u e n c y , a s m a l l b u t s i g n i f i c a n t p o s i t i o n a l - f requency e f f e c t remains when t h e s e v a r i a b l e s a r e s e p a r a t e d (Massaro, Venezky, & T a y l o r , 1 9 7 9 ) .

The r e l a t i o n s h i p s among s i n g l e - l e t t e r p o s i t i o n a l f r e q u e n c y , bigram p o s i t i o n a l f r e q u e n c y , and t r i g r a m p o s i t i o n a l f requency have o n l y begun t o be e x p l o r e d . McClelland and J o h n s t o n (1977) observed t h a t a c c u r a c y of r e p o r t of f o u r - l e t t e r i t e m s was s i g n i f i c a n t l y c o r r e l a t e d w i t h summed s i n g l e - l e t t e r p o s i t i o n a l f requency b u t n o t w i t h bigram p o s i t i o n a l f r e q u e n c y . Bouwhuis (1979) found t h a t s i n g l e - l e t t e r p o s i t i o n a l f r e q u e n c y made a s i g n i f i c a n t c o n t r i b u t i o n t o l e x i c a l d e c i s i o n s a b o u t t h r e e - l e t t e r items. R e a c t i o n times t o words d e c r e a s e d w i t h i n c r e a s e s i n f r e q u e n c y whereas r e a c t i o n times t o pseudowords i n c r e a s e d . S i m i l a r l y , h i g h s i n g l e - l e t t e r p o s i t i o n a l f r e q u e n c y i n c r e a s e d t h e number of "word" r e s p o n s e s t o both words and pseudowords. These s i g n i f i c a n t c o r r e l a t i o n s were c o n s i d e r a b l y d i m i n i s h e d when bigram p o s i t i o n a l f r e q u e n c y was used a s t h e p r e d i c t o r v a r i a b l e . These r e s u l t s imply t h a t t h e power of t h e


b i g r a m f r e q u e n c y m e a s u r e ( s e e C h a p t e r 5 ) w i t h o u r s i x - l e t t e r i t ems may n o t g e n e r a l i z e c o m p l e t e l y t o s m a l l e r l e t t e r - s t r i n g l e n g t h s .

I t is p o s s i b l e t o g e n e r a t e l e t t e r s t r i n g s w h i l e i n d e p e n d e n t l y v a r y i n g summed s i n g l e - l e t t e r p o s i t i o n a l - f r e q u e n c y and summed b i g r a m p o s i t i o n a l - f r e q u e n c y c o u n t s . Wi th some s t r a i n i n g , t h e same c a n b e d o n e f o r summed b i g r a m and summed t r i g r a m c o u n t s . F o r e x a m p l e , nach im h a s ( a c c o r d i n g t o Mayzne r , e t a l . 1 9 6 5 b ) l e g a l b i g r a m s b u t no l e g a l t r i g r a m s . N a t h e r , o n t h e o t h e r h a n d , h a s l e g a l b i g r a m s and l e g a l t r i g r a m s . A l e g a l b ig ram o r a l e g a l t r i g r a m means t h a t t h e s p e l l i n g p a t t e r n o c c u r s w i t h f r e q u e n c i e s a b o v e z e r o i n t h e Mayzner e t a l . t a b l e s . The Mayzner e t a l . t a b l e s m i g h t b e b a s e d o n t o o s m a l l a s a m p l e f o r r e l i a b l e c o u n t s . C o n s e q u e n t l y , we h a v e d e v i s e d t a b l e s f rom t h e Kuce ra and F r a n c i s ( 1 9 6 7 ) m i l l i o n - w o r d l i s t and h a v e u t i l i z e d them i n t h e p r e s e n t p r o j e c t . The d e s c r i p t i o n o f t h e a n a l y s i s and t h e s i n g l e - l e t t e r and b i g r a m t a b l e s a r e g i v e n i n Appendix 5 .2 a n d 5 .3 .

A f u r t h e r i s s u e t h a t n e e d s t o b e c l a r i f i e d is t h e r e l a t i v e i m p o r t a n c e o f t o k e n m e a s u r e s and t y p e m e a s u r e s . Token c o u n t s r e p r e s e n t a summed o c c u r r e n c e f o r some l e t t e r s e q u e n c e , r e g a r d l e s s o f t h e number o f u n i q u e w o r d s wh ich c o n t r i b u t e t o t h i s sum. Type c o u n t s , o n t h e o t h e r h a n d , r e p r e s e n t a sum o f t h e u n i q u e w o r d s i n wh ich a l e t t e r s e q u e n c e o c c u r s , r e g a r d l e s s o f t h e f r e q u e n c i e s o f o c c u r r e n c e o f t h e w o r d s . I n a l l o f t h e e x p e r i m e n t a l work r e p o r t e d s o f a r t h a t used s e q u e n t i a l r e d u n d a n c y m e a s u r e s , t o k e n c o u n t s h a v e b e e n employed . S o l s o and h i s c o l l e a g u e s ( S o l s o , 1 9 7 9 ; S o l s o & K i n g , 1976 ; S o l s o , B a r b u t o , & J u e l , 1979 ; S o l s o , T o p p e r , & Macey, 1 9 7 3 ; T o p p e r , Macey, & S o l s o , 1 9 7 3 ) r e p o r t some t y p e - b a s e d t a b u l a t i o n s b a s e d on t h e Kuce ra and F r a n c i s ( 1 9 6 7 ) word l i s t s b u t no e x p e r i m e n t a l d a t a . However, t h e r e is no a p r i o r i r e a s o n f o r a s s u m i n g t h a t word t o k e n s h a v e g r e a t e r p s y c h o l o g i c a l r e a l i t y t h a n word t y p e s n o r a r e t h e r e e m p i r i c a l d a t a r e l e v a n t t o t h i s q u e s t i o n . We a d d r e s s t h i s i s s u e i n C h a p t e r 5 .

Type-based m e a s u r e s c o u l d b e d e r i v e d from a r e p r e s e n t a t i o n o f a n i n t e r n a l l e x i c o n , b u t t o k e n m e a s u r e s a l s o r e q u i r e t h e e x i s t e n c e o f d i s t r i b u t i o n a l i n f o r m a t i o n i n memory. W h i l e i t is r e a s o n a b l e t o a s sume t h a t some f o r m s o f b o t h t o k e n and t y p e i n f o r m a t i o n m i g h t h a v e p s y c h o l o g i c a l r e a l i t y , how t h e r e a d e r m i g h t a p p l y raw t o k e n m e a s u r e s i n word r e c o g n i t i o n is n o t c o i n p l e t e l y o b v i o u s ( c f . S a v i n , 1 9 6 3 ) . However , some i n t e r e s t i n g a p p r o a c h e s t o u s i n g t o k e n m e a s u r e s embedded w i t h i n t y p e m e a s u r e s h a v e b e e n p r o p o s e d b y Solomon and Pos tman ( 1 9 5 2 ) , S a v i n ( 1 9 6 3 ) , and more r e c e n t l y b y L a n d a u e r and S t r e e t e r

28 CHAPTER 3

( 1 9 7 3 ) . As a n e x a m p l e , t h e v i a b , l e a l t e r n a t i v e s c o u l d b e na r rowed down t o a l l words c o n s i s t e n t w i t h t h e f e a t u r a l i n f o r m a t i o n and t h e r e a d e r m i g h t c h o o s e t h e m o s t f r e q u e n t word from t h i s s e t .

But w h a t e v e r a p p l i c a t i o n m i g h t b e shown f o r f r e q u e n c y i n f o r m a t i o n i n word r e c o g n i t i o n , t h e s p e c i f i c r o l e o f t h e s e m e a s u r e s h a s y e t t o b e d e t e r m i n e d . I f summed f r e q u e n c y ( t o k e n o r t y p e ) i s p s y c h o l o g i c a l l y r e l e v a n t , t h e n t h e u t i l i z a t i o n o f a measu re l i k e b ig ram f r e q u e n c y would r e q u i r e a max imiz ing p r o c e s s . C o n s i d e r t h e t a s k o f p e r c e i v i n g a f i v e - l e t t e r s t r i n g where t h e v i s u a l i n f o r m a t i o n a l l o w s a n a c c e p t a b l e r e s o l u t i o n o f a l l l e t t e r s e x c e p t o n e , e . g . , L l L 2 - L 4 L 5 . Assume t h a t no v i s u a l i n f o r m a t i o n is a v a i l a b l e f o r L 3 . The u s e o f b i g r a m i n f o r m a t i o n r e q u i r e s t h a t L 3 b e s e l e c t e d t o maximize t h e sum o f t h e b ig ram f r e q u e n c i e s o f L 2 L 3 and L 3 L 4 , s e l e c t i n g L 3 f rom a p o o l o f a l l 26 l e t t e r s . I f some v i s u a l i n f o r m a t i o n i s a v a i l a b l e f o r L 3 , t h e n t h e p o o l O E a v a i l a b l e l e t t e r s m i g h t b e r e s t r i c t e d t o t h o s e t h a t were c o m p a t i b l e w i t h t h e a v a i l a b l e i n f o r m a t i o n b u t o t h e r w i s e t h e s t r a t e g y would b e t h e same. For a t r i g r a m s t r a t e g y , a s i m i l a r p r o c e s s c o u l d b e used b u t w i t h t h e max imiz ing o f t h e combined f r e q u e n c i e s f o r L l L 2 L 3 + L 2 L 3 L 4 + L 3 L 4 L 5 . The c o m p l e x i t y o f t h i s s t r a t e g y d o e s n o t n e c e s s a r i l y make i t s p s y c h o l g i c a l r e l e v a n c e s u s p e c t .

A p o t e n t i a l drawback t o summed s i n g l e - l e t t e r , b i g r a m , and t r i g r a m p o s i t i o n a l c o u n t s , p a r t i c u l a r l y where t o k e n c o u n t s a r e u t i l i z e d , i s t h e d o m i n a t i n g r o l e p l a y e d by a s m a l l g r o u p o f h i g h - f r e q u e n c y words . For t h e f o u r - l e t t e r w o r d s , a s a n example , t h e 37 most f r e q u e n t words o f t h i s l e n g t h a c c o u n t f o r a p p r o x i m a t e l y o n e - h a l f o f a l l t o k e n s o f f o u r - l e t t e r words. T h i s g u a r a n t e e s , o n t h e a v e r a g e , a h i g h , p o s i t i v e c o r r e l a t i o n be tween d i f f e r e n t s t a t i s t i c a l m e a s u r e s . However, low summed s i n g l e - l e t t e r p o s i t i o n a l - f r e q u e n c y s t r i n g s w i l l u s u a l l y b e low i n summed p o s i t i o n a l b i g r a m and t r i g r a m f r e q u e n c y , b u t s t r i n g s h i g h i n summed s i n g l e - l e t t e r p o s i t i o n a l f r e q u e n c y a r e n o t n e c e s s a r i l y h i g h i n t h e o t h e r two m e a s u r e s .

F u r t h e r m o r e , s i n c e t h e e x t r e m e l y h i g h f r e q u e n c y w o r d s i n E n g l i s h a r e m o s t l y t h r e e , f o u r , and ( t o a l e s s e r d e g r e e ) f i v e l e t t e r s i n l e n g t h , t h e i n f l u e n c e o f t h e h i g h e s t f r e q u e n c y w o r d s n e c e s s a r i l y d e c r e a s e s w i t h i n c r e a s i n g word l e n g t h . T h u s , we would e x p e c t a l o w e r c o r r e l a t i o n be tween b i g r a m and t r i g r a m c o u n t s i n s e v e n - l e t t e r s t r i n g s t h a n i n f o u r - l e t t e r s t r i n g s .

The c e n t r a l l i m i t a t i o n i n f r e q u e n c y - b a s e d s c h e m e s , e v e n when p o s i t i o n and word l e n g t h s a r e o b s e r v e d , i s t h a t t h e y c a n g e n e r a t e pseudowords wh ich v i o l a t e E n g l i s h p h o n o l o g i c a l and s p e l l i n g c o n v e n t i o n s . For e x a m p l e , t h r s m , s t h s e , and w h r s t a r e


unpronounceable b u t have r e l a t i v e l y h i g h summed bigram p o s i t i o n a l c o u n t s . These can be c o n t r a s t e d w i t h b i p o n , s l e v y , and d u f i p , which have r e l a t i v e l y low summed bigram p o s i t i o n a l c o u n t s , b u t a r e l e g a l from a ru le -governed s t a n d p o i n t . V i o l a t i o n s can be a v o i d e d , f o r t h e most p a r t , by u s i n g p o s i t i o n - s e n s i t i v e f o u r t h - o r d e r a p p r o x i m a t i o n s which a r e a l s o h i g h i n summed t r i g r a m p o s i t i o n a l c o u n t s .

PHONOLOGICALLY-BASED DESCRIPTIONS

An a l t e r n a t i v e t o s t a t i s t i c a l redundancy h a s been t o u s e t h e r e l a t i o n s h i p between s p e l l i n g and sound ( i . e . , p r o n o u n c e a b i l i t y ) as a d e f i n i n g m e t r i c . Gibson e t a l . (1962) found t h a t l e t t e r s of pronounceable pseudowords were more e a s i l y r e c a l l e d i n a f u l l r e p o r t t h a n were l e t t e r s of unpronounceable nonwords ( e . g . , dink v s . G). The a u t h o r s h y p o t h e s i z e d t h a t t h e o p e r a t i v e u n i t i n word p e r c e p t i o n was n o t t h e l e t t e r ( o r t h e whole w o r d ) , b u t a sequence of l e t t e r s which had an i n v a r i a n t s p e l l i n g - t o - s o u n d r e l a t i o n s h i p . However, Gibson e t a l . (1970) o b t a i n e d t h e same r e s u l t s w i t h c o n g e n i t a l l y d e a f s u b j e c t s , t h e r e b y d e m o n s t r a t i n g t h a t t h e s p e l l i n g - t o - s o u n d r e l a t i o n s h i p c o u l d n o t a l o n e a c c o u n t f o r t h e r e s p o n s e d i f f e r e n c e s . I t is l i k e l y t h a t o r t h o g r a p h i c s t r u c t u r e d i f f e r e n c e s (whether f requency-based o r ru le -governed) were c r i t i c a l .

L e t t e r - s o u n d c o r r e s p o n d e n c e s have a l s o been u t i l i z e d i n word r e c o g n i t i o n models by R u b e n s t e i n , Lewis , and Rubens te in (1971) and by Smith and Spoehr ( 1 9 7 4 ) . However, bo th t h e paradigm employed and t h e assumed u s e of l e t t e r - s o u n d r e l a t i o n s h i p s i n t h e l a t t e r two s t u d i e s d i f f e r e d from t h a t i n Gibson e t a l . ( 1 9 6 2 ) . Both Rubens te in e t a l . (1971) and Smith and Spoehr (1974) assumed t h a t l e t t e r r e c o g n i t i o n o c c u r s on t h e b a s i s of l e t t e r f e a t u r e s ; t h e n sounds a r e a t t a c h e d t o l e t t e r s o r l e t t e r sequenLes and l e x i c a l a c c e s s made on t h e b a s i s o f a p h o n o l o g i c a l u n i t . Gibson e t a l . (1962) assumed t h a t word r e c o g n i t i o n o c c u r r e d on t h e b a s i s of h i g h e r - o r d e r v i s u a l u n i t s which t h e r e a d e r formed through e x p e r i e n c e w i t h l e t t e r - s o u n d t r a n s l a t i o n . The r e l i a b i l i t y o f any o f t h e s e h y p o t h e s e s , when viewed i n r e l a t i o n t o t h e c o m p l e x i t i e s of l e t t e r - s o u n d c o r r e s p o n d e n c e s i s q u e s t i o n a b l e ( c f . Venezky, 1 9 7 0 ) .

Fur thermore , some e m p i r i c a l e v i d e n c e i n d i c a t e s t h a t p h o n o l o g i c a l encoding is n o t n e c e s s a r y f o r l e x i c a l a c c e s s (Kleiman, 1975; Levy, 1978; Massaro, 1978; 1979b; Tzeng, Hung, & Wang, 1 9 7 7 ) . However, even i f p h o n o l o g i c a l t r a n s l a t i o n were shown t o p l a y a r o l e i n word r e c o g n i t i o n , p r o n o u n c e a b i l i t y

30 CHAPTER 3

a l o n e would s t i l l be i n a d e q u a t e f o r d e s c r i b i n g o r t h o g r a p h i c s t r u c t u r e . E n g l i s h s p e l l i n g i s c o n s t r a i n e d by p h o n o l o g i c a l c o n v e n t i o n s f i r s t , b u t a l s o by s c r i b a l c o n v e n t i o n s , which out law c e r t a i n p o s s i b l e b u t pronounceable s p e l l i n g s i n s e l e c t e d c o n t e x t s .

RULE-GOVERNED REGULARITY

Rule-governed r e g u l a r i t y d e s c r i b e s t h e p r e d i c t a b l e s t r u c t u r e of t h e o r t h o g r a p h y i n t e r m s of p h o n o l o g i c a l and s c r i b a l c o n s t r a i n t s . However, a c r i t i c a l f e a t u r e of t h i s d e s c r i p t i o n is t h a t t h e p r e d i c t a b l e s t r u c t u r e of l e t t e r o c c u r r e n c e s is u t i l i z e d w i t h o u t any m e d i a t i o n of t h e spoken language . I n c o n t r a s t t o t h e s p e l l i n g - t o - s o u n d d e s c r i p t i o n of Gibson e t a l . (1962) , Rubens te in e t a l . ( 1 9 7 1 ) , and Smith and Spoehr (1974) , u t i l i z a t i o n of o r t h o g r a p h i c s t r u c t u r e i n p e r c e p t u a l r e c o g n i t i o n is assumed t o occur b e f o r e t h e p r i n t e d p a t t e r n is t r a n s l a t e d t o sound. Although much o f t h e s t r u c t u r e of a w r i t t e n a l p h a b e t i c language n e c e s s a r i l y f o l l o w s i ts phonology, a c c e s s t o t h e phonology i s n o t n e c e s s a r y f o r u t i l i z a t i o n of t h e o r t h o g r a p h i c s t r u c t u r e . D i r e c t e v i d e n c e f o r t h i s assumpt ion comes from t h e u t i l i z a t i o n of o r t h o g r a p h i c s t r u c t u r e by d e a f r e a d e r s (Gibson e t a l . , 1 9 7 0 ) . I n a d d i t i o n , S inger ( i n p r e s s ) found t h a t a p h o n o l o g i c a l r e n d e r i n g of words p r e s e n t e d i n an a r t i f i c i a l a l p h a b e t was n o t n e c e s s a r y f o r l e a r n i n g and u t i l i z i n g o r t h o g r a p h i c s t r u c t u r e . I n t h e s e c t i o n s which f o l l o w , both t h e p h o n o l o g i c a l and t h e s c r i b a l c o n s t r a i n t s of E n g l i s h s p e l l i n g s a r e o u t l i n e d .

P h o n o l o g i c a l C o n s t r a i n t s

The pr imary c o n s t r a i n t s on E n g l i s h o r t h o g r a p h y d e r i v e from t h e a l l o w a b l e sequences of sounds i n E n g l i s h words. Thus, / s k / i s an a l l o w a b l e i n i t i a l consonant c l u s t e r and t h e r e f o r e s p e l l i n g s f o r i t e x i s t ( e . g . , e, E, e); on t h e o t h e r hand , /tl/ and / d l / d o n o t occur and never d i d occur i n i t i a l l y i n E n g l i s h words, and t h e r e f o r e no s p e l l i n g f o r t h e s e s e q u e n c e s occur i n E n g l i s h words ( b u t t h e y d o i n T l i n g i t and s e v e r a l o t h e r languages i n which i n i t i a l /tl/ and / d l / a r e l e g a l ) . Compl ica t ing t h i s r e l a t i o n s h i p between sound and s p e l l i n g , however, a r e s e v e r a l f a c t o r s , i n c l u d i n g s c r i b a l p e d a n t r y , which l e a v e u s w i t h s p e l l i n g s f o r (1) sound s e q u e n c e s which once o c c u r r e d , b u t have s i n c e been dropped from t h e language ( e . g . , - W L - , &-, F-), o r f o r ( 2 ) sound sequences t h a t were presumed


t o have o c c u r r e d i n t h e language from which a word was borrowed ( e . g . , psychology, p t a r m i g a n , debt). For psychology, t h i s assumpt ion is s u p p o r t a b l e ; f o r p t a r m i g a n i t is c l e a r l y based on m i s t a k e n etymology; and f o r debt (and v a r i o u s o t h e r s ) , i t is o n l y p a r t i a l l y t r u e , i n t h a t /b/ and /t/ o c c u r r e d i n t h e L a t i n a n c e s t o r of debt ( d e b i t u m ) , b u t n o t a s a f i n a l c l u s t e r .

A f u r t h e r c o m p l i c a t i o n is t h e d e v i a t i o n i n s e r i a l o r d e r of s e v e r a l s p e l l i n g s from t h e o r d e r of sounds which t h e y r e p r e s e n t . Chief among t h e s e i s %, a s p e l l i n g which a t l e a s t some E n g l i s h s p e a k e r s have r e t a i n e d a s /hw/, and -& a s i n b o t t l e , e t c . , which s p e l l s ( i n d e l i b e r a t e s p e e c h ) /al/ (&- and -1e - a r e s c r i b a l r e v e r s a l s of e a r l i e r k- and -e).

B u t even w i t h t h e s e d e v i a t i o n s from e x p e c t e d p r a c t i c e , most E n g l i s h sounds a r e r e p r e s e n t e d i n a m o d e r a t e l y r a t i o n a l f a s h i o n i n t h e o r t h o g r a p h y (Venezky, 1 9 7 0 ) . However, s i n c e E n g l i s h p o s s e s s e s more t h a n one p o t e n t i a l s p e l l i n g f o r a l m o s t e v e r y sound, a second s e t of c o n s t r a i n t s , h e r e c a l l e d s c r i b a l c o n s t r a i n t s , e n t e r i n t o ru le -governed o r t h o g r a p h i c s t r u c t u r e .

S c r i b a l C o n s t r a i n t s

To e x p l a i n t h e rudiments of t h e s e c o n s t r a i n t s , some new te rminology is h e l p f u l .

Vowel s p e l l i n g s a r e c l a s s e d a s p r i m a r y ( 2 , g, i f 0 , g, y ) o r s e c o n d a r y (&, 3, ", ", e t c . ) .

Consonant s p e l l i n g s a r e e i t h e r f u n c t i o n a l l y s i m p l e (b, c, - c h , d, e t c . ) o r f u n c t i o n a l l y compound (11, =, 3, *, and 3).

Graphemic c o n s t r a i n t s r e g u l a t e p r i m a r i l y t h e d i s t r i b u t i o n of (1) geminated ( d o u b l e ) l e t t e r s , ( 2 ) u-v-w, and ( 3 ) y-1. F i r s t , u n l i k e S p a n i s h , E n g l i s h r e s i s t s doubled l e t t e r s i n w o r d - i n i t i a l p o s i t i o n , e s p e c i a l l y c o n s o n a n t s . Only a h a n d f u l of e x c e p t i o n s t o t h i s e x i s t s , p r i m a r i l y i n v o l v i n g t h e form 00 ( e . g . , o o d l e s , o o z e ) . I n o t h e r p o s i t i o n s o n l y 1 5 l e t t e r s c a n d o u b l e : t h o s e t h a t d o n ' t ( o r r a r e l y do) a r e 2 , h, A , i, &, g , 2 , y, w, 5 , y. But t h e r e a r e f u r t h e r r e s t r i c t i o n s . With few e x c e p t i o n s , doubled c o n s o n a n t s do n o t occur a f t e r secondary vowels , and i n f i n a l p o s i t i o n o n l y ff, 11, and a r e common. F i n a l l y , t h e d i g r a p h u n i t s a r e n o t a l lowed t o double . For one , - c h , a pseudogeminate (3) was adopted i n e a r l y modern E n g l i s h , a t a b o u t t h e same t i m e t h a t 3 was adopted t o r e p r e s e n t doubled 9 when i t r e p r e s e n t e d / j / . S i m i l a r l y , & was i n v e n t e d f o r d o u b l e k which now o c c u r s o n l y i n i n f l e c t e d forms of trek ( e . g . , t r e k k i n g ) .

A second s e t of graphemic c o n s t r a i n t s r e g u l a t e t h e d i s t r i b u t i o n of 2-y-w and 4-y. From t h e Middle E n g l i s h p e r i o d

3 2 CHAPTER 3

up t o a b o u t t h e middle of t h e 1 7 t h c e n t u r y , y and v were used i n d i s c r i m i n a t e l y t o r e p r e s e n t / u / and / v / , a l t h o u g h v tended t o be used i n i t i a l l y and 3 e l s e w h e r e . (Accord ing t o P y l e s ( 1 9 6 4 ) , - v was a l s o p r e f e r r e d i n t h e v i c i n i t y of m and n). Digraphs l i k e OJ, when w r i t t e n b e f o r e a vowel might be m i s t a k e n f o r 3; t h e r e f o r e ; was d o u b l e d , and e v e n t u a l l y w r i t t e n y. I n time, 2 i n f i n a l p o s i t i o n as t h e second p a r t of a secondary vowel s p e l l i n g was r e p l a c e d by y, g i v i n g t h e p r e s e n t - d a y a l t e r n a t i o n s -- au/aw, eu/ew, and ou/ow. I n g e n e r a l , t h e w v a r i a n t o c c u r s b e f o r e vowels and i n f i n a l p o s i t i o n ; t h e 3 v a r i a n t o c c u r s e l s e w h e r e . Where 2 would occur a s a p r i m a r y vowel s p e l l i n g i n f i n a l p o s i t i o n , a f i n a l e is added ( e . g . , blue).

For r e a s o n s n o t a l t o g e t h e r c l e a r , b u t r e l a t e d t o t h e ambigui ty of 3-v s p e l l i n g s , y was a l s o e x o r c i s e d from f i n a l p o s i t i o n . But s ince no s i m p l e rep lacement was a v a i l a b l e as was f o r 2 , a n e was added a f t e r t h e l e t t e r , t h u s g i v i n g p r e s e n t - d a y s p e l l i n g s l i k e dove, l o v e , and have, where t h e f i n a l e d o e s n o t mark a f r e e ( l o n g ) vowel p r o n u n c i a t i o n .

S i m i l a r l y , I-y now a l t e r n a t e e x a c t l y a s y and )1! d o , as second e l e m e n t s of a d i g r a p h vowel , t h u s , maid/may, o i l / b o y , and either/-.

Three a d d i t i o n a l f e a t u r e s of E n g l i s h s p e l l i n g which have l i m i t e d u t i l i t y i n s o u n d - t o - s p e l l i n g r u l e s , b u t which a r e i m p o r t a n t f o r t h e r e c o g n i t i o n of r e a l words, a r e d i s c u s s e d b r i e f l y i n t h e f o l l o w i n g s e c t i o n .

Morphemic F e a t u r e s

Morpheme I d e n t i t y . The r e t e n t i o n of morphemic i d e n t i t y a s i n p a i r s l i k e cone /conic i s a n a t u r a l consequence of c o n d i t i o n e d sound change unaccompanied by a c o r r e s p o n d i n g s p e l l i n g change and n o t t h e r e s u l t o f o v e r t s c r i b a l i n t e n t i o n . For t h e most p a r t , however, r e t e n t i o n of morphemic i d e n t i t y is l i m i t e d t o vowels and t h o s e consonant l e t t e r s which a r e s i l e n t i n one form b u t pronounced i n a r e l a t e d one. I n t h e f i r s t c a t e g o r y a r e a l t e r n a t i o n s of t h e form s a n e / s a n i t y and t e l e g r a p h / t e l e g r a p h y ; i n t h e l a t t e r a r e p a i r s a k i n t o s i g n / s i g n a l , bomb/bombard, and hymn/hymnal. Where no s i n g l e s p e l l i n g can s t a n d f o r a p a i r of sounds , c o n s i s t e n t s p e l l i n g of a l lomorphs which d i f f e r by t h o s e sounds is n o t p o s s i b l e . Thus, c o l l i d e / c o l l i s i o n m u s t u t i l i z e d i f f e r e n t s p e l l i n g s f o r /d/ and

I n bound morphemes, s i m i l a r p r o c e s s e s c a n be s e e n a s e x e m p l i f i e d by t h e noun p l u r a l (and t h i r d - p e r s o n s i n g u l a r ) -2 and t h e p a s t t e n s e marker , -3.

/:/.


S e p a r a t i o n of homophones. P a r t l y by a c c i d e n t and p a r t l y by o v e r t a t t e n t i o n , E n g l i s h s p e l l i n g h a s t e n d e d t o d i f f e r e n t i a t e homophones w h e r e v e r o r t h o g r a p h i c l i c e n s e would a l l o w . P a i r s l i k e s e a / s e e , b l u e / b l e w , and r i g h t / w r i t e b e l o n g t o t h e a c c i d e n t c a t e g o r y , b u t f o u l / f o w l , p l a i n / p l a n e , and -- s u n / s o n r e s u l t f rom o v e r t s c r i b a l p r a c t i c e (Vachek , 1 9 5 9 , 1 9 7 3 ; on t h e o r t h o g r a p h i c d i s t i n c t i v e n e s s o f homophones, see O l s o n &

K a u s l e r , 1 9 7 1 ) . The two-let ter word ban . S i n c e a t l e a s t t h e time o f Noah

Webs te r and p r o b a b l y b e f o r e , E n g l i s h l e x i c o g r a p h e r s h a v e a v o i d e d e x t e n d i n g t h e r e p e r t o i r e o f t w o - l e t t e r words beyond a small g r o u p o f f u n c t i o n words ( e . g . , &, of, on, if). Two mechanisms were a d o p t e d f o r l e n g t h e n i n g two- le t te r w o r d s wh ich d i d n ' t q u a l i f y f o r i n c l u s i o n i n t h i s g r o u p : d o u b l i n g t h e f i n a l c o n s o n a n t , as i n ebb, add, odd, a n d a, o r a d d i n g a f i n a l - e , ( e . g . , doe, hoe, &, and * ) . The f o r m e r mechanism h a s c r e a t e d u n i q u e f i n a l c o n s o n a n t c l u s t e r s i n t h a t b, fi, 9, and 1 d o n o t d o u b l e i n f i n a l p o s i t i o n i n a n y o t h e r E n g l i s h words .

T h e s e g r a p h e m i c c o n s t r a i n t s h a v e e v o l v e d i n d e p e n d e n t l y o f s o u n d , f o r u n l i k e t h e o r t h o g r a p h i e s o f o t h e r m a j o r l a n g u a g e s , modern E n g l i s h s p e l l i n g p r e s e r v e s c l e a r e v i d e n c e o f n e a r l y 1 , 3 0 0 y e a r s o f sound c h a n g e , s c r i b a l t a m p e r i n g , p a r t i a l r e f o r m s , and f o r e i g n i n t r u s i o n s . T h e r e is a n u n d e r l y i n g p a t t e r n t o t h i s o r t h o g r a p h y , a s d e s c r i b e d i n Venezky ( 1 9 7 0 ) , b u t t h e r e is a l s o a s u b s t a n t i a l m a r g i n a l mess which c a n o n l y i n p a r t be o r g a n i z e d i n t o s u b p a t t e r n s o r j u s t i f i e d by a p p e a l t o s u c h p r i n c i p l e s as t h e o r t h o g r a p h i c s e p a r a t i o n o f homophones ( e . g . , b e l l / b e l l e ) . N e v e r t h e l e s s , p e r m e a t i n g t h e e n t i r e s p e l l i n g s y s t e m f rom o r g a n i z e d c o r e t o t h e most d i s j o i n t o u t e r f r i n g e s is a n i n t e r a c t i o n be tween p h o n o l o g i c a l and v i s u a l f o r c e s wh ich r a n g e s f rom p r o d u c t i v e c o u n t e r p o i n t a s i n s u c h s p e l l i n g s a s c o n e / c o n i c t o t h e d i s s o n a n c e o f s u c h mots n o i r s a s women.

S i n c e no E n g l i s h l a n g u a g e academy e v e r imposed a g r a n d d e s i g n on E n g l i s h s p e l l i n g , wha t g e n e r a l p r i n c i p l e s t h e r e a r e r e s u l t e d from t h e c o n f l u e n c e o f v a r i o u s s c r i b a l t r a d i t i o n s w i t h t h e p e r i o d i c r a v a g e s o f sound c h a n g e unaccompanied b y s p e l l i n g c h a n g e . Y e t a p r i n c i p l e o f s o r t s d o e s emerge from t h e c u r r e n t s y s t e m , v i z . , "Accede t o a l l v i s u a l i n t e r e s t s up t o , b u t n o t beyond , t h e p o i n t where p a s s a g e from s p e l l i n g t o sound is i m p a i r e d . "

34 CHAPTER 3

P s y c h o l o g i c a l Assumptions

Rule-governed d e s c r i p t i o n s of o r t h o g r a p h i c s t r u c t u r e d i f f e r from o t h e r d e f i n i t i o n s o f o r t h o g r a p h i c s t r u c t u r e i n two a s p e c t s : F i r s t , i n t h e u t i l i z a t i o n of word t y p e s r a t h e r t h a n word t o k e n s , and s e c o n d , i n c l a s s i f y i n g a s r e g u l a r c e r t a i n s p e l l i n g s which d o n o t occur ( y e t ) i n E n g l i s h words and c l a s s i f y i n g a s i r r e g u l a r some t h a t do. The f i r s t d i f f e r e n c e is n o t e s s e n t i a l t o t h e d e f i n i t i o n of o r t h o g r a p h i c s t r u c t u r e , b u t i t is p r o b a b l y more a r e f l e c t i o n of t h e d i f f e r i n g e p i s t e m o l o g i e s of l i n g u i s t s and p s y c h o l o g i s t s . The second d i f f e r e n c e , however, is c e n t r a l t o t h e c o n c e p t of o r t h o g r a p h i c s t r u c t u r e and r e q u i r e s f u r t h e r e x p l i c a t i o n .

The p r i m a r y assumpt ion behind t h e o r t h o g r a p h i c r u l e s p r e s e n t e d h e r e i s t h a t r e a d e r s a b s t r a c t from t h e i r e x p e r i e n c e s w i t h p r i n t e d words t h o s e s p e l l i n g s t h a t a r e p r o d u c t i v e i n present -day E n g l i s h and u s e t h e s e t o f a c i l i t a t e r e c o g n i t i o n . For example, s i l e n t i n i t i a l l e t t e r s , r e g a r d l e s s o f t h e f requency of o c c u r r e n c e o f t h e words i n which t h e y o c c u r , a r e c l a s s i f i e d as i r r e g u l a r s i n c e i t is u n l i k e l y t h a t new words brought i n t o t h e E n g l i s h language would e v e r be s p e l l e d w i t h them. ( S p e l l i n g a n a l o g i e s might p r e s e n t an e x c e p t i o n t o t h i s assumpt ion and c a n n o t be i g n o r e d . However, i t is u n l i k e l y t h a t s i l e n t i n i t i a l s p e l l i n g s would e v e r be w i d e l y e x t e n d e d . )

On t h e o t h e r hand, t h e i n i t i a l s e q u e n c e s E- and e- and t h e f i n a l sequences -eng, -&, and -ofe d o n o t occur i n t h e f i r s t 2 0 , 0 0 0 words i n t h e Thorndike and Lorge ( 1 9 4 4 ) l i s t , y e t t h e y a r e c l a s s i f i e d as o r t h o g r a p h i c a l l y r e g u l a r s i n c e t h e y d o n o t v i o l a t e any p h o n o l o g i c a l o r s c r i b a l p a t t e r n . Thus pseudowords l i k e 9, woach, t r e n g , d e r l , and s t r o f e a r e pronounceable and s t r u c t u r a l l y r e g u l a r , even though t h e y c o n t a i n t r i g r a m s t h a t d o n o t occur i n E n g l i s h words. The p e r c e p t u a l r e c o g n i t i o n of such s t r i n g s r e l a t i v e t o s i m i l a r pseudowords w i t h h i g h e r summed t r i g r a m c o u n t s is an i s sue t h a t remains t o be i n v e s t i g a t e d .

Dichotomy Issue

Another issue which m e r i t s e m p i r i c a l i n v e s t i g a t i o n c o n c e r n s t h e assumed dichotomous d e t e r m i n a n t s of o r t h o g r a p h i c r e g u l a r i t y . Given t h e two d i f f e r e n t c o n s t r a i n t s on o r t h o g r a p h i c s t r u c t u r e d i s c u s s e d above , w e s h o u l d q u e s t i o n whether o r n o t t h e s c r i b a l and p h o n o l o g i c a l e l e m e n t s a r e s e p a r a t e d p s y c h o l o g i c a l l y . Are, f o r example, i r r e g u l a r s t r i n g s l i k e and c k l i b p r o c e s s e d d i f f e r e n t l y from a n i l l e g a l


s t r i n g l i k e t p r i f ? A l l a r e i l l e g a l and non-occurr ing , y e t t h e y d i f f e r i n t y p e o f i l l e g a l i t y . T p r i f c o n t a i n s a n i n i t i a l consonant c l u s t e r t h a t is p h o n o l o g i c a l l y i l l e g a l and t h e r e f o r e s c r i b a l l y non-occurr ing . and c k l i b a r e b o t h p h o n o l o g i c a l l y a c c e p t a b l e , b u t c o n t a i n s c r i b a l l y out lawed f e a t u r e s , v i z . , f i n a l i n and i n i t i a l & i n c k l i b . For example, d o e s t h e p r o b a b i l i t y of c o r r e c t l y i d e n t i f y i n g a t a r g e t l e t t e r depend upon whether i t is i n a p h o n o l o g i c a l l y - i l l e g a l or a s c r i b a l l y - i l l e g a l t e s t s t r i n g ?

AN I N I T I A L ALGORITHM FOR RULE-GOVERNED REGULARITY

The approach t h a t we p r o p o s e , b u t have n o t y e t f u l l y d e v e l o p e d , for r e p r e s e n t i n g t h e d i s p a r a t e p a t t e r n s j u s t d e s c r i b e d is t o c o n s t r u c t a s e t o f g e n e r a t i v e r u l e s which b e g i n by s e l e c t i n g a consonant-vowel-consonant s t r u c t u r e f o r a p h o n o l o g i c a l word. Replacement r u l e s a r e a p p l i e d t o expand l e f t t o r i g h t of e a c h vowel and each c o n s o n a n t u n i t u n t i l a p h o n o l o g i c a l l y l e g a l s t r i n g r e s u l t s . A second s e t of r u l e s t h e n a p p l i e s s o u n d - t o - s p e l l i n g r u l e s t o g e n e r a t e a l e g a l pseudoword (or word) . By r e l a x i n g r u l e s a t v a r i o u s l e v e l s of g e n e r a t i o n , w e c a n t h e n g e n e r a t e l e t t e r s t r i n g s w i t h c o n t r o l l e d i r r e g u l a r i t i e s . For example, by removing t h e p l a c e r e s t r i c t i o n on f i n a l c l u s t e r s of t h e form NASAL + STOP, w e g e n e r a t e unpronounceable f i n a l c l u s t e r s l i k e -9 and -g. On t h e o t h e r hand, a l l o w i n g f i n a l /v/ t o be r e p r e s e n t e d by 1 r a t h e r t h a n a l l o w s s c r i b a l l y i l l e g a l forms l i k e mov and s l a i v . So f a r , a p r e l i m i n a r y s e t of r u l e s f o r g e n e r a t i n g l e g a l m o n o s y l l a b l e s h a s been d e v e l o p e d , drawing on a v a r i e t y o f s o u r c e s ( e . g . , Whorf, 1956; K u r a t h , 1964; Chomsky & Halle, 1968; Venezky, 1 9 7 0 ) . A sample d e r i v a t i o n of a l e g a l pseudoword from t h e s e r u l e s is shown i n Table 3 . 1 .

I n summary, w e have p r e s e n t e d two g e n e r a l a p p r o a c h e s t o d e s c r i b i n g o r t h o g r a p h i c s t r u c t u r e : s t a t i s t i c a l redundancy and ru le -governed r e g u l a r i t y . For t h e f o r m e r , c l a s s m e t r i c s a r e d e r i v e d from f u n c t i o n s on t h e f r e q u e n c i e s w i t h which v a r i o u s s i z e u n i t s occur ( e . g . , summed bigram c o u n t s ) . For t h e l a t t e r c l a s s we have s u g g e s t e d t h a t a comparable metric might be deve loped through a s e t of g e n e r a t i v e r u l e s which c o u l d be v i o l a t e d a t v a r i o u s l e v e l s t o produce nonwords w i t h c o n t r o l l e d d e v i a t i o n s from ru le-governed r e g u l a r i t y .

36 CHAPTER 3

Table 3.1 Derivation of a legal pseudoword (a).

A. Apply Base Generation Rules

Step

1 2 3 4 5 6 7 8 9 10 11 12 13

Rule - Initialize w -----> cvc C/# ------- CC/# -------

> cc > SCL

SCL ------ > s+NASAL NASAL -----> 11. V/else -----> Vf Vf/else ----> vfr Vfr -----> 4 C/-# ----- > cs CS/Vf-# ---- > STOPg STOPg ----- > STOPVg STOPvg ----- > b

Result

#W# # c+v+c # #CC+V+C# # SCL+V+C# #g+NASAL+V+C# #s+"+V+C # #S+"+Vf+C#

tg+n+i+c # #s+E+i+CS#

#s+E+vfr+C#

#s+g+i+STOPg # #s+g+i-+STOPvg# #S+"+i+b#

B. Apply Base-to-Spelling Rules

Step. Rule Result

14 - s/else ----> <s> #<El>*#

15 - n ----> <n> # < sn>i&# 16 - i/-Cs# ---- > <e...e#> #<sne>b<e>#

b ---- > <b> # < snebe># 17 -

------------- (a)Terminal phonological symbols are underlined; terminal spelling symbols occur in wedges, e.g., <a>. A rule of the form x/# ------- > Y is read "Rewrite X as Y when X occurs after juncture ( I ) .'I

4 Experimental Studies

The r e s e a r c h r e p o r t e d i n t h i s book evolved from a commonality o f i n t e r e s t s among t h e a u t h o r s . These i n t e r e s t s p r i m a r i l y c e n t e r e d around f u r t h e r i n g t h e u n d e r s t a n d i n g o f t h e p e r c e p t u a l p r o c e s s e s involved i n word r e c o g n i t i o n and e s p e c i a l l y d e l i n e a t i n g t h e r o l e t h a t o r t h o g r a p h i c s t r u c t u r e p l a y s i n t h e s e p r o c e s s e s . An e x t e n s i o n of an i n t e r e s t i n g s t u d y by Mason (1975) appeared t o be a p r o d u c t i v e way t o a t t a c k t h e problems of o r t h o g r a p h i c s t r u c t u r e and p e r c e p t u a l r e c o g n i t i o n of words. Mason e v a l u a t e d t h e c o n t r i b u t i o n of summed s i n g l e - l e t t e r p o s i t i o n a l f r e q u e n c y i n a t a r g e t s e a r c h t a s k . Good and poor r e a d e r s i n d i c a t e d whether or n o t a s i x - l e t t e r s t r i n g c o n t a i n e d a prede termined t a r g e t l e t t e r . Good r e a d e r s averaged 6 3 msec f a s t e r f o r s t r i n g s h i g h t h a n f o r s t r i n g s low i n p o s i t i o n a l f requency . We were concerned w i t h two p r i m a r y issues w i t h r e s p e c t t o Mason's r e s u l t s . F i r s t , w e q u e s t i o n e d whether a f r e q u e n c y measure of o r t h o g r a p h i c s t r u c t u r e was s u f f i c i e n t t o d e s c r i b e t h e f a c i l i t a t i n g e f f e c t s of s t r u c t u r e on p e r c e p t u a l r e c o g n i t i o n . A s d i s c u s s e d i n Chapter 3 , a ru le -governed d e s c r i p t i o n of o r t h o g r a p h i c s t r u c t u r e may b e a more a p p r o p r i a t e r e p r e s e n t a t i o n of t h e r e a d e r ' s knowledge.

Second, Mason's r e s u l t s appeared t o be h i g h l y v a r i a b l e and w e q u e s t i o n e d whether t h e t a r g e t s e a r c h t a s k u s i n g r e a c t i o n time a s a dependent measure r e v e a l s l a r g e e f f e c t s of o r t h o g r a p h i c s t r u c t u r e . There were a number of r e a s o n s t o s u s p e c t t h e r o b u s t n e s s of t h e e f f e c t i n Mason's s t u d y . S u b j e c t s had o n l y 5 p r a c t i c e t r i a l s and j u s t 7 2 e x p e r i m e n t a l t r i a l s . Each s u b j e c t was t e s t e d on 2 4 words, 24 s t r i n g s h i g h i n p o s i t i o n a l f r e q u e n c y , and 2 4 s t r i n g s low i n p o s i t i o n a l f r e q u e n c y . Given 1 2 good r e a d e r s , t h e r e were 288 o b s e r v a t i o n s minus e r r o r s c o n t r i b u t i n g t o e a c h e x p e r i m e n t a l

38 CHAPTER 4

c o n d i t i o n . Mason found t h a t 100 p r a c t i c e t r i a l s i n a f o l l o w u p exper iment reduced t h e a d v a n t a g e of per formance on s t r i n g s h i g h i n summed p o s i t i o n a l f r e q u e n c y t o a n a v e r a g e of a b o u t 2 2 msec. S i n c e p r a c t i c e t r i a l s reduced t h e a d v a n t a g e by a b o u t t w o - t h i r d s we f e l t t h a t a r e p l i c a t i o n of Mason's s t u d y w i t h improved methodology was n e c e s s a r y t o d e t e r m i n e t h e r e l i a b i l i t y of h e r r e s u l t s .

MASSARO ET AL. 1979 STUDIES

Massaro, Venezky, and Taylor (1979) r e p l i c a t e d Mason's exper iment u s i n g t h e t a r g e t s e a r c h t a s k w i t h s i x t h - g r a d e s u b j e c t s . To o b t a i n g r e a t e r r e l i a b i l i t y , b o t h t h e number of o b s e r v a t i o n s and t h e number of t e s t s t i m u l i were i n c r e a s e d . Fur thermore , t h e l e t t e r s t r i n g s were n o t o n l y h i g h and low i n p o s i t i o n a l f r e q u e n c y b u t a l s o were c o n t r a s t e d a l o n g a n o t h e r dimension which we c a l l e d o r t h o g r a p h i c r e g u l a r i t y . We had n o t y e t deve loped a s y s t e m a t i c ru le -based d e s c r i p t i o n of E n g l i s h o r t h o g r a p h y , b u t we were a b l e t o choose s t r i n g s t h a t appeared t o be r e g u l a r o r i r r e g u l a r . T h e r e f o r e , a l t h o u g h we had no s y s t e m a t i c d e s c r i p t i o n of r e g u l a r i t y , w e f e l t t h a t t h e d e c i s i o n s we made t o choose s t r i n g s t h a t were r e g u l a r and i r r e g u l a r would p r o v i d e a tes t of whether t h e f a c i l i t a t i n g e f f e c t s of o r t h o g r a p h i c s t r u c t u r e c o u l d be c o m p l e t e l y accounted f o r by t h e p o s i t i o n a l f r e q u e n c y h y p o t h e s i s proposed by Mason.

To c r e a t e t h e t e s t s t i m u l i , Massaro e t a l . (1979) s e l e c t e d f o u r anagrams from each o f 40 s i x - l e t t e r words such t h a t t h e anagrams were e i t h e r h i g h or low i n s i n g l e - l e t t e r p o s i t i o n a l f requency and e i t h e r r e g u l a r or i r r e g u l a r . The r e s u l t i n g 2 x 2 f a c t o r i a l d e s i g n p r o v i d e s a d i r e c t a s s e s s m e n t of t h e c o n t r i b u t i o n s of f r e q u e n c y and r e g u l a r i t y on l e t t e r - s t r i n g p e r c e p t i o n . Each of t h e s i x t h g r a d e r s began by t a k i n g a w r i t t e n comprehension t e s t . The t a r g e t s e a r c h t a s k was t h e n i n t r o d u c e d by showing t h e s u b j e c t s t h e v i s u a l d i s p l a y and t h e r e s p o n s e p a n e l . To a c q u a i n t t h e s u b j e c t s w i t h t h e r e s p o n s e p r o c e d u r e , t h e y were f i r s t 'given 50 t r i a l s o f responding "yes" and "no" t o t h e words YES and NO p r e s e n t e d on t h e v i s u a l d i s p l a y . Each s u b j e c t pushed t h e " y e s " b u t t o n w i t h h i s or h e r p r e f e r r e d hand. Next , t h e s u b j e c t s r e c e i v e d 50 p r a c t i c e t r i a l s w i t h random l e t t e r s t r i n g s . The s u b j e c t s were asked t o i n d i c a t e whether o r n o t a t a r g e t l e t t e r was p r e s e n t i n t h e six-letter s t r i n g . Each t r i a l began w i t h t h e p r e s e n t a t i o n of t h e t a r g e t l e t t e r f o l l o w e d 800 msec l a t e r by t h e t e s t l e t t e r s t r i n g . The t e s t l e t t e r s t r i n g remained on u n t i l t h e s u b j e c t

EXPERIMENTS ON LETTER AND WORD PERCEPTION 39

responded. S u b j e c t s were i n s t r u c t e d t o respond " y e s " i f t h e t a r g e t l e t t e r appeared a t l e a s t once i n t h e l e t t e r s t r i n g and "no" i f i t d i d n o t a p p e a r . The t a r g e t l e t t e r appeared i n t h e l e t t e r s t r i n g on h a l f of t h e t r i a l s ( t a r g e t t r i a l s ) and d i d n o t appear on t h e o t h e r h a l f ( c a t c h t r i a l s ) . They were t o l d t o respond as a c c u r a t e l y a s p o s s i b l e . The s u b j e c t s were t e s t e d on each of t h e unique 1 6 0 s t i m u l i , once on t a r g e t t r i a l s and once on c a t c h t r i a l s , g i v i n g roughly 8 0 o b s e r v a t i o n s p e r s u b j e c t a t each o f t h e f o u r e x p e r i m e n t a l c o n d i t i o n s ( l e s s e r r o r t r i a l s ) .

F i g u r e 4 . 1 g i v e s t h e r e s u l t s from t h i s i n i t i a l e x p e r i m e n t . Although t h e r e a c t i o n times were a b o u t 1 2 msec f a s t e r f o r

R-L I-H

F i g u r e 4 . 1 R e a c t i o n t i m e and p e r c e n t a g e c o r r e c t f o r s i x t h g r a d e r s a s a f u n c t i o n of o r t h o g r a p h i c r e g u l a r i t y and summed s i n g l e - l e t t e r p o s i t i o n a l f r e q u e n c y f o r t a r g e t and c a t c h t r i a l s ( f rom Massaro e t a l . , 1 9 7 9 ) (key: p = o r t h o g r a p h i c a l l y r e g u l a r : I = o r t h o g r a p h i c a l l y i r r e g u l a r ; ; = h i g h summed s i n g l e - l e t t e r p o s i t i o n a l f r e q u e n c y ; & = low summed s i n g l e - l e t t e r p o s i t i o n a l f r e q u e n c y ) .

CHAPTER 4

r e g u l a r t h a n f o r i r r e g u l a r s t r i n g s and a b o u t 1 2 msec f a s t e r f o r h i g h t h a n f o r low p o s i t i o n a l f r e q u e n c y , n e i t h e r r e s u l t was s t a t i s t i c a l l y s i g n i f i c a n t . These r e s u l t s imply t h a t n e i t h e r p o s i t i o n a l f r e q u e n c y nor r e g u l a r i t y c o n t r i b u t e s i g n i f i c a n t l y t o p e r c e p t u a l r e c o g n i t i o n i n t h e t a r g e t s e a r c h t a sk . One r e a s o n could be t h a t our m a n i p u l a t i o n of p o s i t i o n a l f r e q u e n c y and r e g u l a r i t y d i d n o t c a p t u r e t h e knowledge t h a t s u b j e c t s u t i l i z e i n p e r c e p t u a l r e c o g n i t i o n . A second p o s s i b i l i t y i s t h a t our m a n i p u l a t i o n of o r t h o g r a p h i c s t r u c t u r e d i d m i r r o r d i f f e r e n c e s i n t h e p s y c h o l o g i c a l r e a l i t y of t h e s e s t r u c t u r e s b u t t h a t t h e t a r g e t s e a r c h t a s k u s i n g r e a c t i o n times is i n s e n s i t i v e t o u t i l i z a t i o n of s t r u c t u r e .

We s u s p e c t e d t h a t t h e s m a l l e f f e c t s i n t h e f i r s t exper iment were p r i m a r i l y due t o t h e t a r g e t s e a r c h t a s k r a t h e r t h a n t o t h e s t r i n g s u t i l i z e d i n t h e e x p e r i m e n t s . T h e r e f o r e , we c a r r i e d o u t two more e x p e r i m e n t s t o c o n t r a s t t h e t a r g e t s e a r c h t a s k u t i l i z i n g r e a c t i o n time (RT) a s a d e p e n d e n t measure w i t h a t a r g e t s e a r c h t a s k u s i n g a c c u r a c y as a d e p e n d e n t measure. We employed c o l l e g e s t u d e n t s r a t h e r t h a n s i x t h g r a d e r s as s u b j e c t s s i n c e t h e y were more r e a d i l y a v a i l a b l e f o r t e s t i n g . One exper iment was a r e p l i c a t i o n of our RT e x p e r i m e n t . The o t h e r , a n a c c u r a c y e x p e r i m e n t , involved a s l i g h t m o d i f i c a t i o n of a more common paradigm used t o s t u d y t h e u t i l i z a t i o n of o r t h o g r a p h i c s t r u c t u r e . I n v a r i a n t s of a Reicher-Wheeler p o s t c u e t a s k (see Chapter l ) , t h e s u b j e c t i s shown a word o r a nonword f o r a b r i e f d u r a t i o n f o l l o w e d by a masking s t i m u l u s . Two a l t e r n a t i v e l e t t e r s a r e t h e n g i v e n and t h e s u b j e c t c h o o s e s which l e t t e r he or s h e t h i n k s was p r e s e n t e d on t h a t t r i a l . I n o r d e r t o make t h i s a c c u r a c y t a s k comparable t o t h e RT t a s k , we modi f ied i t by p r e s e n t i n g j u s t one a l t e r n a t i v e l e t t e r a f t e r t h e masking s t i m u l u s . I n t h i s case t h e s i x - l e t t e r i tem would be p r e s e n t e d f o l l o w e d by a masking s t i m u l u s and t h e n t h e t a r g e t l e t t e r . The t a r g e t l e t t e r would be p r e s e n t i n t h e t e s t item on h a l f o f t h e t r i a l s and n o t p r e s e n t on t h e o t h e r h a l f . The s u b j e c t s would s imply i n d i c a t e whether o r n o t t h e t a r g e t l e t t e r o c c u r r e d i n t h e t e s t l e t t e r s t r i n g . Per formance , i n t e r m s of r e a c t i o n time iri t h e f i r s t e x p e r i m e n t and o v e r a l l a c c u r a c y i n t h e second e x p e r i m e n t , r e f l e c t s how well t h e t e s t s t r i n g s were p e r c e i v e d .

The r e s u l t s of t h e s e two e x p e r i m e n t s a r e shown i n F i g u r e s 4 . 2 and 4 . 3 . I n t h e r e a c t i o n time t a s k , r e a c t i o n times averaged 1 6 msec f a s t e r f o r h i g h t h a n f o r low p o s i t i o n a l - f r e q u e n c y s t r i n g s . Responses were 9 msec f a s t e r f o r r e g u l a r t h a n f o r i r r e g u l a r s t r i n g s . The a c c u r a c y t a s k showed t h a t r e s p o n s e a c c u r a c y was 5% h i g h e r f o r r e g u l a r t h a n f o r


i r r e g u l a r s t r i n g s and 4 % h i g h e r f o r h i g h t h a n f o r low p o s i t i o n a l - f r e q u e n c y s t r i n g s . A l l of t h e s e r e s u l t s were s t a t i s t i c a l l y s i g n i f i c a n t . T h e r e f o r e , a l t h o u g h t h e magni tude of t h e e f f e c t s on r e a c t i o n time f o r t h e a d u l t s was o f t h e same o r d e r of magni tude a s t h a t f o r t h e s i x t h g r a d e r s , lower v a r i a n c e among t h e a d u l t s made t h e e f f e c t s s t a t i s t i c a l l y s i g n i f i c a n t . One l i m i t a t i o n a t t h i s s t a g e of t h e r e s e a r c h was t o know whether o r n o t s i x t h g r a d e r s would g i v e s t a t i s t i c a l l y s i g n i f i c a n t a c c u r a c y r e s u l t s i n t h e a c c u r a c y t a s k . However, s i n c e t h i s l a t t e r ' i n f o r m a t i o n was n o t a v a i l a b l e , w e were f a c e d w i t h t h e problem of comparing t h e magni tude of t h e r e a c t i o n t ime r e s u l t w i t h t h e magni tude of t h e a c c u r a c y r e s u l t and r e a l i z e d t h a t i t resembled t h a t o f comparing a p p l e s and o l i v e s .

I f i t is a c c e p t e d t h a t t h e r e a c t i o n t i m e r e s u l t is small ,

750

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5

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650

F 2 600

550

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Target 0 Catch

nnnn R-H R-L I-H I -L

F i g u r e 4 . 2 R e a c t i o n time and p e r c e n t a g e c o r r e c t f o r c o l l e g e s t u d e n t s a s a f u n c t i o n of o r t h o g r a p h i c r e g u l a r i t y and summed s i n g l e - l e t t e r p o s i t i o n a l f r e q u e n c y f o r t a r g e t and c a t c h t r i a l s ( f rom Massaro e t a l . , 1 9 7 9 ) .

4 2 CHAPTER 4

t h e n one e x p l a n a t i o n f o r t h e small e f f e c t c o u l d t a k e t h e f o l l o w i n g form. I n t h e r e a c t i o n . t i m e t a s k t h e s u b j e c t was g i v e n t h e t a r g e t l e t t e r b e f o r e t h e t e s t s t r i n g was p r e s e n t e d . S i n c e t h e s u b j e c t s imply was r e q u i r e d t o i n d i c a t e whether or n o t t h e t a r g e t was c o n t a i n e d i n t h e t e s t s t r i n g , h e or s h e may n o t have had t o r e s o l v e c o m p l e t e l y a l l o f t h e l e t t e r s i n t h e s t r i n g b e f o r e a c o r r e c t d e c i s i o n was made. For example, suppose a s u b j e c t is l o o k i n g f o r t h e t a r g e t l e t t e r i n t h e l e t t e r s t r i n g s c o s e , deom, and 9 r e s p e c t i v e l y . I n a l l cases t h e a p p r o p r i a t e r e s p o n s e is no , b u t t h e s u b j e c t may be a b l e t o d e c i d e on t h i s f a s t e r w i t h some of t h e s t r i n g s t h a n w i t h o t h e r s . Cons ider t h e f o l l o w i n g argument . There i s some e v i d e n c e t h a t o v e r a l l l e t t e r shape c a n be r e s o l v e d and made a v a i l a b l e t o l a t e r s t a g e s o f p r o c e s s i n g b e f o r e t h e l e t t e r is

'oo!7----- 90

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50 - R H R-L I-H I-L

F i g u r e 4 . 3 P e r c e n t a g e c o r r e c t f o r c o l l e g e s t u d e n t s as a f u n c t i o n of o r t h o g r a p h i c r e g u l a r i t y and summed s i n g l e - l e t t e r p o s i t i o n a l f r e q u e n c y f o r t a r g e t and c a t c h t r i a l s ( f rom Massaro e t a l . , 1 9 7 9 ) .


T a b l e 4 . 1 The s i x s e t s of l e t t e r s based on t h e s i m i l a r i t y r e s u l t s of Bouma (1971) used by Massaro e t a l . ( 1 9 7 9 ) .

1.

2 .

3 .

4.

5 .

6 .

it Although Bouma's a n a l y s i s i n d i c a t e d t h a t t h e f i r s t s e t c o u l d be f u r t h e r d i v i d e d i n t o two sets c o n s i s t i n g of m , n , u , and r , v , w , t h e s e two s e t s were combined because of t h e i r r e l a t i v e s i m i l a r i t y and t o p r o v i d e more r e l i a b l e d a t a by i n c r e a s i n g t h e number of o b s e r v a t i o n s w i t h i n a s e t .

c o m p l e t e l y r e c o g n i z e d (Bouma, 1971; Massaro & S c h m u l l e r , 1 9 7 5 ) . A t a r g e t s e a r c h t a s k c a n be used t o s t u d y t h e f e a t u r e s n e c e s s a r y f o r r e c o g n i t i o n . N e i s s e r (1963, 1967) f o r example, showed t h a t s u b j e c t s s e a r c h e d f a s t e r f o r an uppercase 2 i n a l i s t of curved l e t t e r s t h a n i n a l i s t of l i n e a r l e t t e r s . T h i s r e s u l t i n d i c a t e s t h a t t h e s u b j e c t s were a b l e t o r e j ec t t h e curved l e t t e r s a s f o i l s more q u i c k l y t h a n t h e l i n e a r l e t t e r s . Applying t h i s a n a l y s i s t o t h e p r e s e n t example, s l i b j e c t s s h o u l d be a b l e t o respond "no" q u i c k l y t o t h e e x t e n t t h a t none of t h e l e t t e r s i n t h e t e s t s t r i n g h a s t h e same o v e r a l l a s c e n d e r shape a s t h e t a r g e t l e t t e r b. T h e r e f o r e , i t w i l l t a k e t h e s u b j e c t l o n g e r t o r e j e c t t h e s t r i n g deih t h a n t o r e j e c t t h e s t r i n g deom. The s t r i n g s h o u l d be r e j e c t e d f a s t e s t o f a l l . To t h e e x t e n t t h e s u b j e c t is a b l e t o u t i l i z e t h i s f e a t u r e d e t e c t i o n s t r a t e g y l t h e c o n t r i b u t i o n o f o r t h o g r a p h i c s t r u c t u r e might be a t t e n u a t e d . T h e r e f o r e , i t was of i n t e r e s t t o s e e t h e e x t e n t t o which s u b j e c t s appeared t o be u s i n g t h i s s t r a t e g y i n

4 4 CHAPTER 4

t h e r e a c t i o n time and a c c u r a c y tasks . We h y p o t h e s i z e d t h a t t h i s s t r a t e g y would be u t i l i z e d i n t h e r e a c t i o n time b u t n o t t h e a c c u r a c y t a s k . I n t h e a c c u r a c y t a s k , t h e s u b j e c t w i l l r e s o l v e t h e l e t t e r s t r i n g t o t h e d e e p e s t l e v e l p o s s i b l e . I n t h e r e a c t i o n time t a s k , having t h e t a r g e t s p e c i f i e d i n advance and having t h e t e s t l e t t e r s t r i n g v i s i b l e d u r i n g t h e p r o c e s s i n g i n t e r v a l w i l l a l l o w t h e s u b j e c t t o t e r m i n a t e e a r l y on some c a t c h t r i a l s .

To e v a l u a t e t h i s h y p o t h e s i s , t h e l o w e r c a s e l e t t e r s o f t h e a l p h a b e t were grouped i n t o s i x g r o u p s based on t h e s i m i l a r i t y r e s u l t s of Bouma ( 1 9 7 1 ) . T h i s grouping is g i v e n i n T a b l e 4.1. The r e l a t i o n s h i p between each t a r g e t l e t t e r and t e s t s t r i n g was d e f i n e d i n t e r m s of t h e number of n o n t a r g e t l e t t e r s i n t h e s t r i n g t h a t were members of t h e same s e t as t h e t a r g e t l e t t e r .

P

I I 1 1 2 3 5501 ,!,

NUMBER OF SIMILAR NONTARGETS

F i g u r e 4 . 4 R e a c t i o n time i n t h e t a r g e t s e a r c h t a s k a s a f u n c t i o n o f t h e number of s i m i l a r n o n t a r g e t l e t t e r s i n t h e t e s t s t r i n g (from Massaro e t a l . , 1 9 7 9 ) .

EXPERIMENTS ON LETTER AND WORD PERCEPTION 4 5

For example, t h e t e s t s t r i n g l i s v e r would have two l e t t e r s (1 and i-) from t h e same s e t a s t h e l e t t e r t , two (v and LJ from t h e same s e t as u, and none from t h e same set a s 5. F i g u r e s 4.4 and 4.5 g i v e t h i s s i m i l a r i t y a n a l y s i s f o r r e a c t i o n time and a c c u r a c y t a s k s r e s p e c t i v e l y . The r e s u l t s show h i g h l y s i g n i f i c a n t e f f e c t s on c a t c h t r i a l s i n t h e r e a c t i o n time t a s k , s u p p o r t i n g t h e i d e a of a f e a t u r e d e t e c t i o n s t r a t e g y i n t h e r e a c t i o n t i m e t a s k .

The number of l e t t e r s i n t h e t e s t s t r i n g having t h e same o v e r a l l shape a s t h e t a r g e t s h o u l d n o t be i m p o r t a n t on t a r g e t t r i a l s i n t h e r e a c t i o n time t a s k s . The t a r g e t l e t t e r m u s t be c o m p l e t e l y r e s o l v e d b e f o r e a " y e s " r e s p o n s e can be made. I f t h e s u b j e c t s s imply responded " y e s " whenever t h e o v e r a l l shape of t h e t a r g e t was p e r c e i v e d , r e c o g n i t i o n e r r o r s would be h i g h l y

I 1 I 1 2 3


F i g u r e 4 .5 P e r c e n t a g e c o r r e c t i n t h e t a r g e t s e a r c h t a sk a s a f u n c t i o n of t h e number of s i m i l a r n o n t a r g e t l e t t e r s i n t h e tes t s t r i n g ( f rom Massaro e t a l . , 1 9 7 9 ) .

4 6 CHAPTER 4

p r o b a b l e . S i n c e a h i g h a c c u r a c y c r i t e r i o n was e n f o r c e d , we would n o t e x p e c t t h e number of s i m i l a r l y shaped l e t t e r s t o be a c r i t i c a l v a r i a b l e on t a r g e t t r i a l s . A s c a n be s e e n i n F i g u r e 4 . 4 , t h e s i m i l a r i t y v a r i a b l e had no s i g n i f i c a n t e f f e c t on t a r g e t t r i a l s i n t h e r e a c t i o n time e x p e r i m e n t .

I n t h e a c c u r a c y t a s k , per formance on c a t c h t r i a l s tended t o d e c r e a s e w i t h i n c r e a s e s i n t h e number of s i m i l a r n o n t a r g e t l e t t e r s . I n c o n t r a s t , per formance improved somewhat on t a r g e t t r i a l s w i t h i n c r e a s e s i n t h e number of s i m i l a r n o n t a r g e t l e t t e r s . Although t h e s e r e s u l t s were n o t s t a t i s t i c a l l y s i g n i f i c a n t , t h e y show t h a t s i m i l a r i t y may a l s o p l a y a r o l e i n t h e a c c u r a c y t a s k .

Although it is d i f f i c u l t t o compare d i r e c t l y t h e magni tude of t h e e f f e c t s of a c c u r a c y w i t h t h o s e of r e a c t i o n time, t h e s i m i l a r i t y a n a l y s i s makes such a comparison more meaningfu l . The r e a c t i o n time s t u d y i n d i c a t e d s m a l l e f f e c t s of o r t h o g r a p h i c s t r u c t u r e r e l a t i v e t o t h e e f f e c t s of s i m i l a r i t y . The a c c u r a c y s t u d y r e v e a l e d l a r g e e f f e c t s o f o r t h o g r a p h i c s t r u c t u r e r e l a t i v e t o s m a l l e f f e c t s of s i m i l a r i t y . C o n t r a s t i n g t h e s e two v a r i a b l e s i n e a c h t a s k might a l l o w a more r e l i a b l e a s s e s s m e n t of t h e c o n t r i b u t i o n of o r t h o g r a p h i c s t r u c t u r e . From t h i s a n a l y s i s it a p p e a r s t h a t o r t h o g r a p h i c s t r u c t u r e p l a y s a l a r g e r r o l e i n t h e a c c u r a c y s t u d y t h a n it d o e s i n t h e r e a c t i o n time s t u d y . One of t h e p r i m a r y m o t i v a t i o n s of t h e p r e s e n t se t of e x p e r i m e n t s was t o e x p l o r e t h e d i f f e r e n c e s between t h e s e two t a s k s . Of c o u r s e , i t is n o t t h e t a s k s themselves t h a t a r e i n t e r e s t i n g b u t r a t h e r , what t h e y r e v e a l a b o u t t h e p e r c e p t u a l r e c o g n i t i o n of l e t t e r s t r i n g s .

The f o l l o w i n g s e t of e x p e r i m e n t s was a l s o deemed n e c e s s a r y because of t h e l i m i t a t i o n s i n t h e m a n i p u l a t i o n of o r t h o g r a p h i c s t r u c t u r e i n our p r e v i o u s s t u d i e s . Although w e a t t e m p t e d t o choose r e g u l a r and i r r e g u l a r s t r i n g s f o r e a c h l e v e l of h i g h o r low p o s i t i o n a l f r e q u e n c y , we were n o t c o n f i d e n t t h a t w e had been c o m p l e t e l y s u c c e s s f u l . I t was d i f f i c u l t t o s e l ec t regular - low p o s i t i o n a l - f r e q u e n c y items and i r r e g u l a r - h i g h p o s i t i o n a l - f r e q u e n c y items. T h i s fo l lowed from t h e f a c t t h a t p o s i t i o n a l f requency and our i n t u i t i v e i m p r e s s i o n of o r t h o g r a p h i c r e g u l a r i t y might have been h i g h l y c o r r e l a t e d . T h e r e f o r e , we may have i n a d v e r t e n t l y confounded r e g u l a r i t y w i t h p o s i t i o n a l f r e q u e n c y i n t h a t t h e h i g h p o s i t i o n a l - f r e q u e n c y items were more r e g u l a r t h a n t h e low p o s i t i o n a l - f r e q u e n c y items. I t remained a p o s s i b i l i t y t h a t t h e e f f e c t of p o s i t i o n a l f r e q u e n c y would be e l i m i n a t e d i f w e c o u l d f i n d items t h a t were e q u a l l y r e g u l a r f o r h i g h and low p o s i t i o n a l f r e q u e n c i e s . T h e r e f o r e , we r e f i n e d our d e s c r i p t i o n


o f o r t h o g r a p h i c r e g u l a r i t y and c h o s e a new s e t of items on t h e b a s i s o f t h e s e r u l e s f o r t h e p r e s e n t e x p e r i m e n t s . The r u l e s a r e p r e s e n t e d i n Appendix 4 . 1 A .

I n a d d i t i o n t o s e l e c t i n g new items w e a l s o employed word s t i m u l i i n t h e e x p e r i m e n t s . Krueger (1979) s p e c u l a t e d t h a t a much l a r g e r f a c i l i t a t i o n i n t h e t a r g e t s e a r c h t a s k would be found w i t h words t h a n w i t h pseudowords. By i n c l u d i n g w i t h our f o u r c a t e g o r i e s o f m e a n i n g l e s s anagrams t h e words from which t h e y were d e r i v e d , w e c o u l d p r o v i d e a d i r e c t e v a l u a t i o n of t h e f a c i l i t a t i n g e f f e c t s of word s t r u c t u r e r e l a t i v e t o p o s i t i o n a l f r e q u e n c y and r e g u l a r i t y . We a l s o saw t h e p o t e n t i a l f o r t e s t i n g a wider r a n g e of formal d e s c r i p t i o n s of o r t h o g r a p h i c s t r u c t u r e i n t h e p r e s e n t e x p e r i m e n t s . A s i n d i c a t e d e a r l i e r , t h e q u a l i t a t i v e t e s t p r o v i d e d by t h e f a c t o r i a l d e s i g n is l i m i t e d . A good d e s c r i p t i o n of o r t h o g r a p h i c s t r u c t u r e must a l s o d e s c r i b e per formance f o r i n d i v i d u a l l e t t e r s t r i n g s . T h e r e f o r e , we planned t o a n a l y z e per formance a s a f u n c t i o n of i n d i v i d u a l l e t t e r s t r i n g s i n t h e p r e s e n t s t u d i e s . These a n a l y s e s would go s i g n i f i c a n t l y beyond t h e q u a l i t a t i v e compar isons between word, pseudoword, and nonword items of p r e v i o u s s t u d i e s . A second m o t i v a t i o n f o r i n c l u d i n g word items was t h a t any d e s c r i p t i o n of o r t h o g r a p h i c s t r u c t u r e must n o t be l i m i t e d t o nonword items b u t m u s t a l s o be f u n c t i o n a l f o r word items. I f i n some manner l e x i c a l ( i . e . , word) i d e n t i t y o v e r r u l e s o r t h o g r a p h i c s t r u c t u r e , t h e n t h e l a t t e r would n o t be p s y c h o l o g i c a l l y r e l e v a n t i n r e a d i n g .

T h e r e f o r e t h e f i r s t two e x p e r i m e n t s of t h e p r e s e n t s e t of e x p e r i m e n t s c a n be c o n s i d e r e d t o be a d i r e c t r e p l i c a t i o n of t h e Massaro e t a l . (1979) e x p e r i m e n t s which have j u s t been d e s c r i b e d . However, t h e p r e s e n t e x p e r i m e n t s i n c l u d e d a new s e t o f items a l o n g w i t h t h e c o r r e s p o n d i n g word s t i m u l i . I n t h i s s e n s e , t h e e x p e r i m e n t s conform t o t h e e x p e r i m e n t a l framework g i v e n by Sidman (1960) i n t h a t we a r e both r e p l i c a t i n g and e x t e n d i n g p r e v i o u s e x p e r i m e n t s . F i g u r e 4.6 i l l u s t r a t e s t h e f i v e t y p e s of i t e m s used i n a l l o f t h e c u r r e n t e x p e r i m e n t s .

STUDY 1: I N I T I A L REPLICATION

Procedure

Two e x p e r i m e n t s were c a r r i e d o u t w i t h 1 4 s u b j e c t s i n e a c h exper iment . F i g u r e 4 . 7 g i v e s a s c h e m a t i c r e p r e s e n t a t i o n of t h e p r o c e d u r e s f o r t h e a c c u r a c y and RT e x p e r i m e n t s . I n t h e a c c u r a c y e x p e r i m e n t t h e t e s t l e t t e r s t r i n g was p r e s e n t e d f o r a

48 CHAPTER 4

wrntei ahcger rdnuet (1421)

s h o r t d u r a t i o n fo l lowed immediately by a masking s t i m u l u s . The d u r a t i o n of t h e t e s t item was a d j u s t e d f o r each s u b j e c t i n o r d e r t o o b t a i n an a v e r a g e of 75% c o r r e c t a c r o s s a l l c o n d i t i o n s i n t h e t a s k . The t a r g e t l e t t e r fo l lowed t h e 208 msec masking s t i m u l u s . The s u b j e c t ' s t a s k was t o i n d i c a t e by p r e s s i n g t h e a p p r o p r i a t e b u t t o n whether or n o t t h e t a r g e t l e t t e r was c o n t a i n e d i n t h e t e s t l e t t e r s t r i n g . I n t h e RT e x p e r i m e n t t h e t a r g e t l e t t e r was p r e s e n t e d f o r 500 msec fo l lowed by a 1 sec blank p e r i o d . The t e s t s t r i n g was t h e n p r e s e n t e d and remained on u n t i l t h e s u b j e c t responded " y e s " o r "no" w i t h r e s p e c t t o whether or n o t t h e t a r g e t l e t t e r o c c u r r e d i n t h e t e s t s t r i n g . A r e a s o n a b l e amount o f p r a c t i c e was g i v e n on both tasks . The t e s t items were s i x - l e t t e r s t r i n g s c o n s i s t i n g of 4 0 words and 160 anagrams c r e a t e d by t h e f a c t o r i a l combina t ion of h i g h or

rntewi hreagc edtrnu (526)

low p o s i t i o n a l - f r e q u e n c y

I winter charge

words I turned I (1293)

Regular

Orthographic Regularity

and r e g u l a r or i r r e g u l a r

Positional Frequency

High Low

triwen trewin chager greach drunet tredun (1438) (540)

I I

F i g u r e 4 . 6 The f i v e t y p e s of i t e m s and examples of e a c h t y p e used i n t h e e x p e r i m e n t s . The number i n e a c h c e l l is t h e a v e r a g e summed s i n g l e - l e t t e r p o s i t i o n a l f r e q u e n c y f o r t h a t item t y p e (based on t h e Mayzner & T r e s s e l t , 1965, c o u n t s ) .


s t r u c t u r e . On any t r i a l , any of t h e f i v e t y p e s of s t r i n g s c o u l d be p r e s e n t e d a s e i t h e r a c a t c h o r t a r g e t t r i a l . The tes t s t r i n g s a r e p r e s e n t e d i n Appendix 4 . 1 B . The d e t a i l s of t h e method, p r o c e d u r e , and r e s u l t s o f t h e two t a s k s a r e p r e s e n t e d i n Appendix 4 . 1 .

O r t h o g r a p h i c S t r u c t u r e

F i g u r e s 4.8 and 4.9 p r e s e n t t h e r e s u l t s from t h e a c c u r a c y and RT t a s k s as a f u n c t i o n of t h e f i v e classes of items. Performance i n t h e a c c u r a c y t a s k depended g r e a t l y on t h e s t r u c t u r e of t h e t e s t s t r i n g . Words were r e c o g n i z e d 1 2 % more o f t e n t h a n t h e b e s t r e g u l a r h i g h items. The r e g u l a r s t r i n g s were judged 8 % more a c c u r a t e l y t h a n t h e i r r e g u l a r s t r i n g s . Accuracy was 5% h i g h e r f o r h i g h p o s i t i o n a l - f r e q u e n c y

PRECUE RT

Target Test Letter Display

:-+L I- 500 I 1000 I

POSTCUE ACCURACY

Test Mask Target Letter

F i g u r e 4 . 7 Schemat ic r e p r e s e n t a t i o n s of t h e p r e c u e r e a c t i o n time and p o s t c u e a c c u r a c y e x p e r i m e n t s .

50 CHAPTER 4

1 I I I

s t r i n g s t h a n f o r low p o s i t i o n a l - f r e q u e n c y s t r i n g s . A l l of t h e s e r e s u l t s were s t a t i s t i c a l l y s i g n i f i c a n t . The d e t a i l e d r e s u l t s and t h e s t a t i s t i c a l a n a l y s e s are p r e s e n t e d i n Appendix 4 . 1 .

I n t h e RT t a s k , r e a c t i o n times t o words were o n l y 7 msec f a s t e r t h a n r e a c t i o n times t o r e g u l a r - h i g h anagrams. Regular items were judged 2 3 msec f a s t e r t h a n i r r e g u l a r items, whereas h i g h p o s i t i o n a l - f r e q u e n c y items were responded t o o n l y 4 msec f a s t e r t h a n low p o s i t i o n a l - f r e q u e n c y items. Only t h e e f f e c t of r e g u l a r i t y was s t a t i s t i c a l l y s i g n i f i c a n t . The d e t a i l e d r e s u l t s and s t a t i s t i c a l a n a l y s e s a r e p r e s e n t e d i n Appendix 4.1.

The h i g h l y s i g n i f i c a n t e f f e c t s of o r t h o g r a p h i c s t r u c t u r e on r e s p o n s e a c c u r a c y and t h e r e l a t i v e l y minor , and f o r t h e most p a r t , n o n s i g n i f i c a n t e f f e c t s of o r t h o g r a p h i c s t r u c t u r e on r e a c t i o n time p r o v i d e a d i r e c t r e p l i c a t i o n of our p r e v i o u s

50 WORD R-H R-L I-H I-L

F i g u r e 4 . 8 P e r c e n t a g e c o r r e c t a s a f u n c t i o n of d i s p l a y t y p e f o r t a r g e t and c a t c h t r i a l s i n t h e p o s t c u e a c c u r a c y t a s k of S tudy 1.


I Y

5

w E 600 I-

P 550-

work. These r e s u l t s u n d e r s c o r e t h e r e l i a b i l i t y of t h e r e g u l a r i t y and p o s i t i o n a l - f r e q u e n c y e f f e c t s on a c c u r a c y by d e m o n s t r a t i n g a g e n e r a l i z a t i o n t o both a new sample o f s u b j e c t s and a new sample of s t i m u l u s items ( C l a r k , 1 9 7 3 ) . N e i t h e r r e g u l a r i t y nor p o s i t i o n a l f r e q u e n c y , however, a p p e a r s t o be s u f f i c i e n t t o a c c o u n t f o r t h e s t r o n g a c c u r a c y a d v a n t a g e found f o r words. The i s sue of whether or n o t o r t h o g r a p h i c s t r u c t u r e r a t h e r t h a n l e x i c a l i d e n t i t y c a n a c c o u n t for t h e word a d v a n t a g e w i l l be d e l a y e d u n t i l a more d e t a i l e d d i s c u s s i o n and e v a l u a t i o n of o r t h o g r a p h i c s t r u c t u r e is p r e s e n t e d .

-

S i m i l a r i t y E f f e c t s

To t e s t f o r t h e e f f e c t s of s i m i l a r i t y between t h e t a r g e t l e t t e r s o u g h t i n a d i s p l a y and t h e l e t t e r s a c t u a l l y o c c u r r i n g

F i g u r e 4 . 9 R e a c t i o n time and p e r c e n t a g e c o r r e c t a s a f u n c t i o n of d i s p l a y t y p e for t a r g e t and c a t c h t r i a l s i n t h e p r e c u e r e a c t i o n t i m e t a s k o f S tudy 1.

52 CHAPTER 4

Table 4 . 2 For e a c h o f t h e 26 l e t t e r s i s l i s t e d t h e o t h e r l e t t e r s i n t h e a l p h a b e t t h a t were e r r o n e o u s l y i d e n t i f i e d a s t h a t l e t t e r more t h a n 5% of t h e t i m e (from Bouma, 1 9 7 1 ) .

S i m i l a r S i m i l a r T a r g e t N o n t a r g e t L e t t e r s T a r g e t N o n t a r g e t L e t t e r s

a c , e l m , n , 0 , s , x , z n a , e l s , u , x

C 0 P 4

i . 1, t V W

j 1 W V

k t , x X

Y V

i n t h e d i s p l a y , t h e d a t a were pooled a c r o s s a l l f i v e d i s p l a y t y p e s and r e p a r t i t i o n e d . The b a s i s f o r t h i s r e p a r t i t i o n i n g was t h e c l a s s i f i c a t i o n o f each t r i a l ' s t a r g e t l e t t e r a c c o r d i n g t o which l e t t e r s a r e l i k e l y t o be s e e n a s v e r y s i m i l a r t o t h e t a r g e t . The c l a s s i f i c a t i o n was d e r i v e d from t h e l o w e r c a s e s i n g l e - l e t t e r c o n f u s a b i l i t y s t u d y o f Bouma ( 1 9 7 1 ) shown i n t a b l e 2 . 4 . We counted a n o n t a r g e t l e t t e r a s s i m i l a r t o t h e t a r g e t l e t t e r i f t h e n o n t a r g e t l e t t e r was e r r o n e o u s l y i d e n t i f i e d a s t h e t a r g e t more t h a n 5% of t h e t ime i n Bouma's s t u d y . T a b l e 4 .2 p r e s e n t s t h e s i m i l a r i t y c l a s s i f i c a t i o n a c c o r d i n g t o t h i s a n a l y s i s . For example, g i v e n t h e t a r g e t


l e t t e r &, t h e s i m i l a r n o n t a r g e t l e t t e r s a r e k, E, and - u. T h i s means t h a t t h e s t i m u l u s l e t t e r s k t k, p, a n d 2 were i d e n t i f i e d a s b more t h a n 5% o f t h e t i m e i n Bouma's s t u d y . Each u n i q u e t r i a l i n o u r t a r g e t s e a r c h t a s k was t h e n d e s c r i b e d by t h e number o f n o n t a r g e t l e t t e r s i n t h e d i s p l a y t h a t were s i m i l a r t o t h e t a r g e t a c c o r d i n g t o t h i s c las - s i f i c a t i o n . Rough ly 46 , 3 3 , 1 3 , and 7 % o f e a c h s u b j e c t ' s t r i a l s f e l l i n t o t h e c a t e g o r i e s z e r o , o n e , two , a n d t h r e e s i m i l a r l e t t e r s ( o t h e r t h a n t h e t a r g e t l e t t e r i t s e l f ) , r e s p e c t i v e l y .

F i g u r e s 4.10 and 4 .11 p r e s e n t t h e a c c u r a c y and r e a c t i o n t ime r e s u l t s a s a f u n c t i o n o f t h e number o f s i m i l a r n o n t a r g e t l e t t e r s i n t h e d i s p l a y . T a r g e t v e r s u s c a t c h t r i a l s i s t h e c u r v e p a r a m e t e r i n t h e f i g u r e s . I n t h e a c c u r a c y t a s k , a c c u r a c y i n c r e a s e d w i t h i n c r e a s e s i n t h e number o f s i m i l a r n o n t a r g e t

100

90 k Y 8 80

a

0

B 70

I2 k

60

50

I 1 I I

1 I 1 L 0 1 2 3


F i g u r e 4.10 P e r c e n t a g e c o r r e c t a s a f u n c t i o n o f t h e number o f s i m i l a r n o n t a r g e t l e t t e r s i n t h e t e s t s t r i n g s i n t h e a c c u r a c y e x p e r i m e n t o f S t u d y 1.

54 CHAPTER 4

l e t t e r s on t a r g e t t r i a l s and d e c r e a s e d on c a t c h t r i a l s . The l a r g e s i m i l a r i t y e f f e c t s i n t h e a c c u r a c y t a s k c o n t r a s t w i t h t h e s m a l l e r e f f e c t s o f Massaro e t a l . shown i n F i g u r e 4 . 5 . The p r e s e n t a n a l y s i s may have provided a more s e n s i t i v e t e s t o f s i m i l a r i t y t h a n t h e Massaro e t a l . a n a l y s i s s i n c e t h e c o n f u s i o n s e t s were computed i n a more p r e c i s e manner. I n p a r t i c u l a r , t h e p r e s e n t a n a l y s i s a l l o w s f o r asymmetr ic c o n f u s i o n s . Although c is c o n s i d e r e d t o b e a s i m i l a r n o n t a r g e t l e t t e r g i v e n t h e t a r g e t l e t t e r d, e , 9, o r 2 , t h e o n l y s i m i l a r n o n t a r g e t l e t t e r f o r t h e t a r g e t l e t t e r i s t h e l e t t e r 0. I n t h e r e a c t i o n t i m e t a s k , r e a c t i o n time i n c r e a s e d w i t h i n c r e a s e s i n t h e number of s i m i l a r t a r g e t l e t t e r s on c a t c h t r i a l s b u t d i d not change much on t a r g e t t r i a l s . T h i s r e s u l t p r o v i d e s a d i r e c t r e p l i c a t i o n o f t h e s i m i l a r i t y a n a l y s i s i n t h e Massaro e t a l . s t u d y shown i n F i g u r e 4.4.

650 700r---

+--+Target 500 t r E l 450 h 1 2 3


F i g u r e 4.11 R e a c t i o n time a s a f u n c t i o n of t h e number o f s i m i l a r n o n t a r g e t l e t t e r s i n t h e t e s t s t r i n g i n t h e r e a c t i o n t i m e exper iment o f S tudy 1.


Targe t -Catch D i f f e r e n c e s

Accuracy was 1 2 % h i g h e r f o r c a t c h t r i a l s t h a n f o r t a r g e t t r i a l s and t h i s e f f e c t i n t e r a c t e d w i t h d i s p l a y t y p e s ( c f . F i g u r e 4 . 8 ) . Reac t ion times were 47 msec s lower f o r c a t c h t r i a l s t h a n f o r t a r g e t t r i a l s ( c f . F i g u r e 4 . 9 ) . The r e s u l t s show t h a t s u b j e c t s i n an a c c u r a c y t a s k tend t o be more a c c u r a t e on c a t c h t r i a l s t h a n on t a r g e t t r i a l s whereas t h e y t e n d t o t a k e l o n g e r on c a t c h t r i a l s i n t h e r e a c t i o n time e x p e r i m e n t . Given t h a t t h e s e r e s u l t s d o n o t come from t h e same e x p e r i m e n t , t h e y c a n n o t be i n t e r p r e t e d i n te rms of a speed a c c u r a c y t r a d e - o f f . However, r e s p o n s e a c c u r a c y i n t h e RT t a s k was a l s o s i g n i f i c a n t l y h i g h e r f o r c a t c h t h a n f o r t a r g e t t r i a l s ( F i g u r e 4.9) and t h i s r e s u l t might a c c o u n t f o r t h e l o n g e r r e a c t i o n times on c a t c h t r i a l s i n t h e r e a c t i o n t i m e t a s k .

A c e n t r a l q u e s t i o n r a i s e d by t h i s s t u d y c o n c e r n s t h e n a t u r e of t h e s i m i l a r i t i e s and t h e d i f f e r e n c e s between a c c u r a c y and r e a c t i o n time paradigms. R e s u l t s from a c c u r a c y and r e a c t i o n time s t u d i e s a r e f r e q u e n t l y r e g a r d e d a s c o n v e r g e n t i n d i c a t i o n s of common p e r c e p t u a l p r o c e s s i n g . S y s t e m a t i c d i f f e r e n c e s between t h e a c c u r a c y and RT e f f e c t s would s u g g e s t t h a t p e r c e p t u a l p r o c e s s e s may n o t be t h e same i n b o t h c a s e s . Thus, two i m p o r t a n t q u e s t i o n s a r e whether o r n o t a c c u r a c y and r e a c t i o n time r e s u l t s can be p r e d i c t e d from a common p r o c e s s i n g model, and i f so , how t h e d i f f e r e n t s t i m u l u s envi ronments of t h e a c c u r a c y and r e a c t i o n time t a s k s c a u s e t h e observed d i f f e r e n c e s i n t h e magnitude of t h e e f f e c t s . The a c c u r a c y and t h e r e a c t i o n time t a s k s w i l l be e v a l u a t e d i n t h e framework of t h e i n f o r m a t i o n p r o c e s s i n g model. I n o r d e r t o b e t t e r unders tand t h e e f f e c t s of t a r g e t and c a t c h t r i a l s and t o b e t t e r e x p l i c a t e our i n t e r p r e t a t i o n of t h e p r o c e s s e s i n t h e a c c u r a c y and r e a c t i o n t i m e t a s k s , we w i l l p r e s e n t an i n f o r m a t i o n p r o c e s s i n g a n a l y s i s of per formance i n t h e a c c u r a c y and r e a c t i o n time t a s k s .

INFORMATION PROCESSING MODEL

With t h e r e g i s t r a t i o n of a l e t t e r s t r i n g a s a n image upon t h e r e t i n a , s e n s o r y t r a n s d u c t i o n b e g i n s . F e a t u r e s a r e e x t r a c t e d s i m u l t a n e o u s l y ( i n p a r a l l e l ) from e a c h l e t t e r p o s i t i o n i n t h e d i s p l a y and a r e e n t e r e d i n t o p r e p e r c e p t u a l v i s u a l s t o r a g e . F e a t u r e e x t r a c t i o n i s a t e m p o r a l l y ex tended p r o c e s s so t h a t t h e c o n t e n t s of p r e p e r c e p t u a l v i s u a l s t o r a g e

CHAPTER 4

b u i l d up over t ime. Concurren t w i t h t h e e s t a b l i s h m e n t o f t h e new c o n t e n t s of p r e p e r c e p t u a l v i s u a l s t o r a g e , t h e p r i m a r y r e c o g n i t i o n p r o c e s s t r a n s f o r m s t h e c u r r e n t c o n t e n t s of p r e p e r c e p t u a l v i s u a l s t o r a g e i n t o s y n t h e s i z e d v i s u a l memory. The c o n t e n t s of s y n t h e s i z e d v i s u a l memory a r e c o n t i n u a l l y monitored by a d e c i s i o n p r o c e s s which, i n t h e case of t h e precue t a r g e t s e a r c h t a s k , endeavors t o match t h e t a r g e t w i t h t h e f r e s h l y r e s o l v e d and c o n t i n u o u s l y updated l e t t e r s t r i n g i n s y n t h e s i z e d v i s u a l memory, a s i n T u r v e y ' s (1973) c o n c u r r e n t - c o n t i n g e n t model.

To d e r i v e s p e c i f i c p r e d i c t i o n s from t h e model, i t is n e c e s s a r y t o make a few assumpt ions a b o u t t h e p r i m a r y r e c o g n i t i o n p r o c e s s and t h e d e c i s i o n p r o c e s s . Exper imenta l s u p p o r t f o r t h e s e assumpt ions p r e v i o u s l y h a s been d e m o n s t r a t e d (Massaro, 1 9 7 9 a ) . The f i r s t assumpt ion is t h a t knowledge of o r t h o g r a p h i c s t r u c t u r e c o n t r i b u t e s a n independent s o u r c e o f knowledge a b o u t t h e l e t t e r s t r i n g . A c c o r d i n g l y , e x p e r i e n c e d r e a d e r s w i l l be b i a s e d t o i n t e r p r e t t h e l e t t e r s t r i n g as one t h a t is o r t h o g r a p h i c a l l y s t r u c t u r e d . T h e r e f o r e , t o t h e e x t e n t t h a t t h e l e t t e r s be ing r e s o l v e d from p r e p e r c e p t u a l v i s u a l s t o r a g e form w e l l - s t r u c t u r e d l e t t e r s e q u e n c e s , t h e y may be r e s o l v e d w i t h fewer f e a t u r e s or b e f o r e a l l f e a t u r e s have been e x t r a c t e d . I n c o n t r a s t , a p o o r l y - s t r u c t u r e d s t r i n g w i l l r e q u i r e n e a r l y comple te f e a t u r a l i n f o r m a t i o n f o r r e c o g n i t i o n because o r t h o g r a p h i c knowledge w i l l p r o v i d e no a d d i t i o n a l a s s i s t a n c e . Thus, t h e c o n t e n t s o f s y n t h e s i z e d v i s u a l memory a r e e s t a b l i s h e d by p r i m a r y r e c o g n i t i o n more q u i c k l y and a c c u r a t e l y f o r w e l l - s t r u c t u r e d t h a n f o r p o o r l y - s t r u c t u r e d s t r i n g s .

The second assumpt ion is r e l a t e d t o t h e d e c i s i o n a l g o r i t h m i n t h e t a r g e t s e a r c h t a sk . When t h e t a r g e t l e t t e r is known i n advance, t h e d e c i s i o n p r o c e s s m o n i t o r s t h e c o n t i n u o u s l y emerging c o n t e n t s o f s y n t h e s i z e d v i s u a l memory s e e k i n g a match t o t h e t a r g e t . A l l l e t t e r p o s i t i o n s a r e moni tored i n d e p e n d e n t l y and i n p a r a l l e l . The d e c i s i o n p r o c e s s m a i n t a i n s two c r i t e r i a or d e c i s i o n a x e s , ana logous t o t h e model of memory s e a r c h developed by Atk inson and J u o l a ( 1 9 7 4 ) . Whenever a l e t t e r p o s i t i o n e x c e e d s t h e f i r s t c r i t e r i o n i n resemblance t o t h e t a r g e t , a match is assumed t o have been found, p r o c e s s i n g t e r m i n a t e s , and a p o s i t i v e r e s p o n s e is e x e c u t e d . Whenever a l e t t e r p o s i t i o n is s u f f i c i e n t l y d i s s i m i l a r t o t h e t a r g e t t o exceed t h e second c r i t e r i o n , t h e l e t t e r is c l a s s i f i e d as a f o i l . Let ter p o s i t i o n s t h a t have n o t y e t been r e s o l v e d s u f f i c i e n t l y t o be c l a s s i f i e d a s t a r g e t o r f o i l c o n t i n u e t o be r e s o l v e d u n t i l t h e y c a n be c l a s s i f i e d or u n t i l f u r t h e r


r e s o l u t i o n is n o t p o s s i b l e . When a l l l e t t e r p o s i t i o n s have been c l a s s i f i e d a s f o i l s , a n e g a t i v e r e s p o n s e i s e x e c u t e d .

I f t h e v i s u a l s t i m u l u s i s impoverished s o t h a t f u l l r e s o l u t i o n of a l l l e t t e r p o s i t i o n s is n o t p o s s i b l e , a d e c i s i o n i s f o r c e d when no f u r t h e r r e s o l u t i o n is p o s s i b l e . Given t h a t t h e f u l l y r e s o l v e d o r c l e a r l y " s e e n " l e t t e r s have been c l a s s i f i e d as f o i l s , a g u e s s r e s p o n s e m u s t be e x e c u t e d based upon t h e remain ing "unseen" l e t t e r s . The o b s e r v e r ' s p r o b a b i l i t y o f g u e s s i n g t h a t one of t h e unreso lved l e t t e r s is a t a r g e t is a j o i n t f u n c t i o n of a p r i o r i e x p e c t a t i o n s t h a t any g i v e n l e t t e r w i l l be a t a r g e t and t h e number of u n r e s o l v e d l e t t e r s . These e x p e c t a t i o n s a r e d e r i v e d from i n s t r u c t i o n s and p a s t e x p e r i e n c e .

For t h e p r e c u e RT t a s k , t h e f o l l o w i n g p r e d i c t i o n s a l s o f o l l o w d i r e c t l y from t h e model. D e c i s i o n time is a d i r e c t f u n c t i o n of t h e r e s o l u t i o n t ime of t h e s t i m u l u s s t r i n g and t h e r e f o r e is i n f l u e n c e d by t h e o r t h o g r a p h i c r e d u n d a n c i e s t h a t c a n be e x p l o i t e d i n t h e s t i m u l u s . The t i m e t o c o r r e c t l y i d e n t i f y a t a r g e t i n t h e l e t t e r s t r i n g is a f u n c t i o n s o l e l y of t h e time r e q u i r e d t o r e s o l v e t h e t a r g e t and w i l l , on t h e a v e r a g e , be s h o r t e r t h a n t h e time r e q u i r e d t o e x h a u s t i v e l y c l a s s i f y a l l l e t t e r s a s f o i l s on a c a t c h t r i a l . I d e n t i f i c a t i o n time f o r t h e t a r g e t l e t t e r is i n f l u e n c e d by t h e o r t h o g r a p h i c c o n s t r a i n t s among t h e l e t t e r s i n t h e c a t c h s t r i n g . The emphasis on a c c u r a c y i n t h e RT t a s k d i s p o s e s t h e o b s e r v e r t o m a i n t a i n s t r i c t c r i t e r i a which, f o r t h e most p a r t , p r e c l u d e e r r o r s .

I n a p o s t c u e t a s k , r e c o g n i t i o n and d e c i s i o n p r o c e s s e s a n a l o g o u s t o t h o s e f o r t h e p r e c u e t a s k a r e assumed t o o p e r a t e , e x c e p t t h a t t h e c o n t e n t s of s y n t h e s i z e d v i s u a l memory m u s t be m a i n t a i n e d a w a i t i n g t h e a r r i v a l and r e c o g n i t i o n of t h e t a r g e t l e t t e r . The s t i m u l u s l e t t e r s t r i n g is r e s o l v e d a s f u l l y a s t h e combined v i s u a l i n f o r m a t i o n and o r t h o g r a p h i c s t r u c t u r e a l l o w and is r e t a i n e d a w a i t i n g p r e s e n t a t i o n of t h e t a r g e t . Once t h e t a r g e t is i d e n t i f i e d , i t is compared w i t h however much of t h e l e t t e r s t r i n g was r e s o l v e d . I f a match is found, a p o s i t i v e r e s p o n s e is e x e c u t e d . Fol lowing t h e argument of Thompson and Massaro ( 1 9 7 3 ) , i t i s assumed t h a t t h e e x a c t f e a t u r a l s i m i l a r i t y of t h e u n r e s o l v e d l e t t e r s t o t h e t a r g e t l e t t e r is n o t d i r e c t l y a v a i l a b l e t o t h e d e c i s i o n p r o c e s s and d o e s n o t i n f l u e n c e t h e g u e s s p r o b a b i l i t y . O r t h o g r a p h i c s t r u c t u r e i n f l u e n c e s a c c u r a c y f o r bo th t a r g e t and c a t c h t r i a l s because i t i n f l u e n c e s t h e number of l e t t e r s t h a t a r e a c c u r a t e l y p e r c e i v e d .

I t may seem s u r p r i s i n g t h a t t h e Thompson and Massaro (1973) and t h e Massaro e t a l . (1979) s t u d i e s r e v e a l e d no

CHAPTER 4

s i g n i f i c a n t e f f e c t s o f l e t t e r s i m i l a r i t y . Even i f f e a t u r a l i n f o r m a t i o n is n o t t r a n s m i t t e d t o s y n t h e s i z e d v i s u a l memory we would e x p e c t i n c o r r e c t s y n t h e s e s t o be s i m i l a r t o t h e t e s t l e t t e r . For example, g i v e n t h e t e s t l e t t e r 0, we would e x p e c t t h a t r e c o g n i t i o n e r r o r s w i l l be more l i k e l y t o c o n s i s t of c and - e t h a n I and 2. One f a c t o r t h a t may work a g a i n s t o b s e r v a t i o n of t h i s phenomenon may be t h a t t h e t e s t d i s p l a y was f o l l o w e d by a masking s t i m u l u s i n t h e a c c u r a c y t a s k and t h e r e is now some e v i d e n c e t h a t f e a t u r e s of t h e mask c o n t r i b u t e t o p e r c e p t u a l memory of t h e t e s t (Kallman & Massaro, 1979; Smi th , H a v i l a n d , Reder , Brownel l , & Adams, 1 9 7 6 ) . Given t h e c o n t r i b u t i o n of t h e mask, i n c o r r e c t r e s p o n s e s might be more e a s i l y p r e d i c t e d by t h e f e a t u r e s of t h e mask t h a n t h e f e a t u r e s of t h e t e s t . A second r e a s o n f o r o b s e r v i n g s m a l l s i m i l a r i t y e f f e c t s i n t h e a c c u r a c y s t u d i e s is t h a t t h e a c c u r a c y s t u d i e s w i t h l e t t e r s t r i n g s employ a f o r c e d - c h o i c e r e s p o n s e s i t u a t i o n so t h a t t h o s e few t r i a l s t h a t i n v o l v e i n c o r r e c t p e r c e p t u a l s y n t h e s e s a r e u n l i k e l y t o a g r e e w i t h t h e i n c o r r e c t r e s p o n s e a l t e r n a t i v e . The s y s t e m a t i c l e t t e r c o n f u s i o n s u s u a l l y found i n s i n g l e - l e t t e r r e c o g n i t i o n s t u d i e s c o u l d depend on an open-ended s e t of l e t t e r r e s p o n s e a l t e r n a t i v e s . However, i t is a l s o p o s s i b l e t o o b s e r v e s i g n i f i c a n t s i m i l a r i t y e f f e c t s a s i n t h e p r e s e n t a c c u r a c y s t u d y ( c f . F i g u r e 4 . 1 8 ) . The p a t t e r n of t h e s e r e s u l t s is c o n s i s t e n t w i t h t h e i d e a t h a t s i m i l a r l e t t e r s may be m i s t a k e n l y i d e n t i f i e d a s t h e t a r g e t . Hence, a c c u r a c y on t a r g e t t r i a l s i n c r e a s e s w i t h t h e number of s i m i l a r l e t t e r s t o t h e t a r g e t i n t h e t e s t s t r i n g , b u t a c c u r a c y on c a t c h t r i a l s d e c r e a s e s a s t h e number of s i m i l a r l e t t e r s t o t h e t a r g e t is i n c r e a s e d .

I t is p o s s i b l e t o q u a n t i f y t h e p r o c e s s i n g model i n o r d e r t o d e s c r i b e t h e q u a n t i t a t i v e r e s u l t s of t h e t a r g e t s e a r c h t a s k . I n an a c c u r a c y t a s k , i t is assumed t h a t t h e l e t t e r s t r i n g is p e r c e i v e d ( i . e . , r e s o l v e d ) a s f u l l y a s p o s s i b l e . R e s o l u t i o n of t h e d i s p l a y i s a d i r e c t f u n c t i o n of b o t h t h e f e a t u r a l i n f o r m a t i o n a v a i l a b l e and t h e o r t h o g r a p h i c s t r u c t u r e of t h e t e s t s t r i n g . S i n c e each o f t h e f o u r t y p e s of m e a n i n g l e s s l e t t e r s t r i n g s was composed by making anagrams of a s i x - l e t t e r word, t h e same l e t t e r s were p r e s e n t a c r o s s t h e f i v e d i s p l a y . t y p e s . The f i v e d i s p l a y t y p e s were a l s o p r e s e n t e d a t t h e same i n t e n s i t y and d u r a t i o n s . T h e r e f o r e , t h e f e a t u r a l i n f o r m a t i o n may be assumed t o be c o n s t a n t a c r o s s t h e d i s p l a y t y p e s . However, t h e d i s p l a y t y p e s d i f f e r w i t h r e s p e c t t o o r t h o g r a p h i c s t r u c t u r e and t h e s e d i f f e r e n c e s can a c c o u n t f o r t h e performance d i f f e r e n c e s a c r o s s t h e f i v e d i s p l a y t y p e s . T h e r e f o r e , t h e number of l e t t e r s r e s o l v e d , R , w i l l depend on t h e d i s p l a y t y p e .


I t i s n e c e s s a r y t o d e s c r i b e a d e c i s i o n r u l e t h a t a l l o w s t h e s u b j e c t t o s e l e c t a " y e s " o r "no" r e s p o n s e . I t is assumed t h a t i f one of t h e r e s o l v e d l e t t e r s is i d e n t i c a l t o t h e t a r g e t , a " y e s " r e s p o n s e is e x e c u t e d . I f t h e t a r g e t l e t t e r is n o t c o n t a i n e d i n t h e se t of r e s o l v e d l e t t e r s , a " y e s " r e s p o n s e i s a f u n c t i o n of t h e number of u n r e s o l v e d l e t t e r s and t h e r e a d e r ' s e x p e c t a t i o n , E , t h a t some l e t t e r i n t h e s i x - l e t t e r s t r i n g w i l l be i d e n t i c a l t o t h e t a r g e t . S i n c e E i s t h e e x p e c t a t i o n f o r a whole s i x - l e t t e r tes t s t r i n g c o n t a i n i n g t h e t a r g e t , t h e n E/6 is t h e e x p e c t a t i o n t h a t any s i n g l e l e t t e r i n t h e t e s t s t r i n g is i d e n t i c a l t o t h e t a r g e t . The e x p e c t a t i o n v a l u e E would be some f u n c t i o n o f i n s t r u c t i o n s , f e e d b a c k , and how o f t e n t h e t a r g e t l e t t e r is a c t u a l l y s e e n i n t h e t e s t s t r i n g . T h e r e f o r e , t h e p r o b a b i l i t y o f a " y e s " r e s p o n s e t o t h e t a r g e t t r i a l i s g i v e n by Equat ion 1 f o r l e t t e r s t r i n g s of l e n g t h 6.

The l e f t - h a n d term of Equat ion 1 i n d i c a t e s t h a t R - s i x t h s of t h e time one o f t h e r e s o l v e d l e t t e r s w i l l be i d e n t i c a l t o t h e t a r g e t and t h e o b s e r v e r w i l l respond " y e s " w i t h p r o b a b i l i t y one. On t h e remain ing t r i a l s , 1 - R/6, t h e t a r g e t was n o t r e s o l v e d and t h e o b s e r v e r g u e s s e s w i t h p r o b a b i l i t y E /6 weighted by t h e number of u n r e s o l v e d l e t t e r s ( 6 - R ) .

For c a t c h t r i a l s , t h e o b s e r v e r w i l l never f i n d t h e t a r g e t and , t h e r e f o r e , i s i n an i m p e r f e c t knowledge s t a t e u n l e s s h e o r s h e r e s o l v e s a l l of t h e l e t t e r s . T h e r e f o r e , t h e l i k e l i h o o d of a " y e s " r e s p o n s e is s imply t h e o b s e r v e r ' s e x p e c t a t i o n t h a t a g i v e n t e s t l e t t e r is a t a r g e t l e t t e r , E/6, weighted by t h e number of u n r e s o l v e d t a r g e t l e t t e r s , 6 - R:

P(Yes lCatch) = (6 - R ) x (E/6) ( 2 )

Of c o u r s e , t h e l i k e l i h o o d of b e i n g c o r r e c t on c a t c h t r i a l s is t h e complement of Equat ion ( 2 ) :

P(No1Catch) = 1 - [ ( 6 - R ) x ( E / 6 ) ] ( 3 )

The model was a p p l i e d t o t h e r e s u l t s of t h e a c c u r a c y e x p e r i m e n t . The model was f i t t o t h e 1 0 a v e r a g e r e s p o n s e a c c u r a c i e s ( t h e f i v e d i s p l a y t y p e s on t a r g e t p r e s e n t t r i a l s and t h e f i v e d i s p l a y t y p e s on c a t c h o r t a r g e t a b s e n t t r i a l s ) . The f i t was o b t a i n e d u s i n g a l e a s t - s q u a r e s parameter e s t i m a t i o n r o u t i n e ( C h a n d l e r , 1 9 6 9 ) . S i x p a r a m e t e r s were e s t i m a t e d from t h e d a t a : one e x p e c t a t i o n p a r a m e t e r , E , and an e s t i m a t e o f t h e

60 CHAPTER 4

number of l e t t e r s f u l l y r e s o l v e d , R , f o r e a c h o f t h e f i v e d i s p l a y t y p e s . The o b t a i n e d f i t was q u i t e good; t h e r o o t mean squared d e v i a t i o n was o n l y 1.3%. Although i t is d i f f i c u l t t o a p p r e c i a t e t h e q u a n t i t a t i v e g o o d n e s s - o f - f i t f o r such a model e s t i m a t i n g s i x p a r a m e t e r s f o r 1 0 d a t a p o i n t s , t h e o b t a i n e d parameter v a l u e s n o n e t h e l e s s a r e r e v e a l i n g . The s u b j e c t s were c l e a r l y informed of t h e e q u a l number of t a r g e t and c a t c h t r i a l s i n t h e exper iment and t h e r e f o r e , t h e y s h o u l d have adopted a n E-value o f .5 . However, t h e observed g r e a t e r a c c u r a c y f o r c a t c h t r i a l s would a p p e a r t o s u g g e s t a b i a s toward "no" r e s p o n s e s o r an a p p a r e n t E-value r a t h e r c l o s e t o z e r o . I n f a c t , t h e e s t i m a t e d E-value was . 4 6 s u g g e s t i n g t h a t t h e s u b j e c t s possessed a t most a v e r y s l i g h t b i a s . The s t r o n g imbalance between c a t c h a c c u r a c y and t a r g e t a c c u r a c y i s a l o g i c a l consequence of t h e model even when l i t t l e o r no b i a s is p r e s e n t . Although t h e r e a r e no a p r i o r i v a l u e s o f t h e R p a r a m e t e r s t o which t h e e s t i m a t e s may be compared, t h e o b t a i n e d e s t i m a t e s f o r R p r o v i d e a r e a s o n a b l e s c a l i n g f o r t h e f i v e t y p e s o f items. These v a l u e s a r e shown i n T a b l e 4.3 a s P o s t c u e (S tudy 1) .

While t h e s p e c i f i c a t i o n of a q u a n t i t a t i v e model p r e d i c t i n g r e a c t i o n times is c o n s i d e r a b l y more complex, i t n o n e t h e l e s s s tems d i r e c t l y from t h e above i n f o r m a t i o n p r o c e s s i n g a n a l y s i s . The r e a c t i o n t ime on a t a r g e t t r i a l i s t h e s u m of t h e t i m e needed t o r e s o l v e t h e t a r g e t l e t t e r i n t h e l e t t e r s t r i n g p l u s t h e time needed t o i n i t i a t e and e x e c u t e t h e c o r r e c t r e s p o n s e . The r e s o l u t i o n time f o r t h e t a r g e t l e t t e r i s a f u n c t i o n of i t s v i s u a l p r o p e r t i e s and of t h e o r t h o g r a p h i c s t r u c t u r e o f t h e l e t t e r s t r i n g i n which t h e t a r g e t o c c u r s . S i n c e o r t h o g r a p h i c s t r u c t u r e a f f e c t s t h e t i m e needed t o r e s o l v e t h e l e t t e r s t r i n g , o r t h o g r a p h i c s t r u c t u r e is a parameter of t h e d i s t r i b u t i o n o f t h e r e a c t i o n t i m e s . The expec ted v a l u e of t h i s d i s t r i b u t i o n p l u s a c o n s t a n t g i v e s a v e r a g e RT f o r t a r g e t t r i a l s . (Response i n i t i a t i o n and e x e c u t i o n t i m e is assumed t o be c o n s t a n t o r a t l e a s t d i s t r i b u t e d i n d e p e n d e n t l y o f t h e e f f e c t o f p r i m a r y i n t e r e s t . )

For c a t c h t r i a l s , t h e RT i s t h e sum of a c o n s t a n t time f o r response e x e c u t i o n p l u s t h e maximum time needed t o c l a s s i f y a l l l e t t e r s a s f o i l s . C l a s s i f i c a t i o n t ime is based upon t h e j o i n t d i s t r i b u t i o n o f comple t ion t i m e s f o r e a c h o f t h e f o i l s on t h e n o n t a r g e t t r i a l s . These d i s t r i b u t i o n s have a s p a r a m e t e r s t h e s i m i l a r i t y o f t h e f o i l t o t h e t a r g e t , o t h e r v i s u a l p r o p e r t i e s which a f f e c t t h e o v e r a l l e a s e of r e s o l v i n g t h e f o i l , t h e i n f l u e n c e o f o r t h o g r a p h i c s t r u c t u r e , and f i n a l l y t h e s u b j e c t ' s c r i t e r i o n f o r a v o i d i n g f a l s e a l a r m s . Having o u t l i n e d t h e model


T a b l e 4.3 E s t i m a t e s o f p e r c e p t u a l r e s o l u t i o n ( R ) and a p r i o r i e x p e c t a t i o n ( E ) o f t h e o c c u r r e n c e o f a t a r g e t t r i a l and t h e r o o t mean s q u a r e d (RMS) d e r i v a t i o n s f o r t h e a c c u r a c y t a s k s i n S t u d i e s 1 and 2.

R E RMS ( i n % )

Task Word R-H R-L I - H I - L

5.20 4.40 3.72 3.40 2.98 .459 1 . 2 7

5.22 4.38 3 .56 3 .26 2 .86 . 5 5 0 1 . 7 0

P o s t c u e

( S t u d y 1)

( S t u d y 2 )

P r e c u e

( S t u d y 2 ) 4.87

Combined Da ta 5.08

P o s t c u e P r e c u e

4.29 3 .84 3.85

4.33 3.68 3 . 5 1

3.42 . 8 8 0 1 .67

3.08 2.54

.514

.823

t o t h i s l e v e l o f d e t a i l , w e w i l l p r o c e e d no f u r t h e r . U n l i k e t h e a c c u r a c y model where t h e f i t o f t h e model was e n l i g h t e n i n g a b o u t presumed s u b j e c t b i a s i n t h e t a s k , t h e q u a l i t a t i v e f e a t u r e s o f t h e RT d a t a f o l l o w r a t h e r d i r e c t l y f rom t h e q u a l i t a t i v e d e s c r i p t i o n o f t h i s model . The c o m p l e t i o n o f t h e q u a n t i f i c a t i o n o f t h i s model m i g h t p r o v e a n i n t e r e s t i n g e x e r c i s e b u t would b e u n l i k e l y t o b e e x t r e m e l y r e v e a l i n g , p a r t i c u l a r l y s i n c e t h e e f f e c t s o f o r t h o g r a p h i c s t r u c t u r e were v e r y s m a l l .

STUDY 2: PRECUE VERSUS POSTCUE

Whereas i t is n o t p o s s i b l e t o compare d i r e c t l y t h e m a g n i t u d e o f a c c u r a c y and RT e f f e c t s , t h e d i f f e r e n c e s i n a c c u r a c y b e t w e e n words and i r r e g u l a r - l o w a n a g r a m s i n t h e

62 CHAPTER 4

a c c u r a c y t a s k was 21%. The d i f f e r e n c e be tween t h e s e same c o n d i t i o n s i n t h e RT t a s k was o n l y 34 msec o r 5 .8% o f t h e a v e r a g e RT o f 581 msec. 3 o e s t h i s r e p r e s e n t a r ea l d i f f e r e n c e i n t h e u t i l i z a t i o n o f o r t h o g r a p h i c s t r u c t u r e i n t h e two t a s k s ? I f s o , what p r o p e r t i e s o f t h e t a s k s a l l o w more o f a c o n t r i b u t i o n o f o r t h o g r a p h i c s t r u c t u r e i n o n e t a s k t h a n i n t h e o t h e r ?

The o b s e r v a t i o n o f s i g n i f i c a n t a d v a n t a g e s f o r w o r d s and pseudowords o v e r nonwords and s i n g l e l e t t e r s i n t h e p o s t c u e R e i c h e r t a s k ( B a r o n & T h u r s t o n , 1973; R e i c h e r , 1969; Thompson &

Massa ro , 1973 ; W h e e l e r , 1 9 7 0 ) and t h e a b s e n c e o f t h e s e e f f e c t s i n p r e c u e d e t e c t i o n t a s k s ( B j o r k & Estes, 1973 ; E s t e s , B j o r k , &

S k a a r , 1974; M a s s a r o , 1973; Thompson & M a s s a r o , 1 9 7 3 ) h a s l e d t o t h e s u g g e s t i o n t h a t p r e c u i n g p r e c l u d e s t h e c o n t r i b u t i o n o f o r t h o g r a p h i c s t r u c t u r e . The s u b j e c t i n a p r e c u e t a s k p r e s u m a b l y m a t c h e s t h e f e a t u r e s of t h e remembered t a r g e t l e t t e r d i r e c t l y t o t h e f e a t u r e s o f t h e incoming v i s u a l d i s p l a y . T h i s s t r a t e g y p r e c l u d e s u s i n g o r t h o g r a p h i c s t r u c t u r e t o a s s i s t i n r e s o l u t i o n o f t h e d i s p l a y . Thus , o n e h y p o t h e s i s is t h a t p r e c u i n g p r o m o t e s s m a l l e r a d v a n t a g e s f o r s t r u c t u r e d d i s p l a y s . S t u d y 2 t e s t s w h e t h e r a p r e c u e , p e r se , a c c o u n t s f o r d i m i n i s h e d e f f e c t s o f o r t h o g r a p h i c s t r u c t u r e . The p o s t c u e a c c u r a c y t a s k o f t h e S t u d y 1 was r e p l i c a t e d i n o n e c o n d i t i o n w h i l e a c o m p a r a b l e p r e c u e a c c u r a c y t a s k was u s e d i n t h e o t h e r c o n d i t i o n . I f p r e c u i n g a l w a y s a l l o w s m a t c h e s t o b e made a t a f e a t u r e d e t e c t i o n l e v e l , t h e n t h e e f f e c t s o f o r t h o g r a p h i c s t r u c t u r e s h o u l d b e s e v e r e l y a t t e n u a t e d i n t h e p r e c u e a c c u r a c y t a s k . On t h e o t h e r h a n d , i f t h e d i s p l a y i n t h e a c c u r a c y t a s k i s r e s o l v e d t o t h e f u l l e s t e x t e n t p o s s i b l e and o r t h o g r a p h i c s t r u c t u r e c o n t r i b u t e s t o r e s o l u t i o n , t h e n t h e r e s u l t s f o r p r e c u e and p o s t c u e a c c u r a c y s h o u l d b e c o m p a r a b l e e x c e p t , p e r h a p s , f o r d i f f e r e n t i a l memory l o a d s i n t h e two c o n d i t i o n s .

The t e s t s t r i n g s , a p p a r a t u s , and d i s p l a y s e q u e n c e s were i d e n t i c a l t o t h o s e o f t h e a c c u r a c y e x p e r i m e n t i n S t u d y 1. One h a l f o f t h e s u b j e c t s r e c e i v e d t h e p r e c u e t a s k o n t h e f i r s t d a y and t h e p o s t c u e t a s k o n t h e second d a y ; f o r t h e r e m a i n i n g s u b j e c t s t h i s o r d e r was r e v e r s e d . The p r e c u e t a s k i n v o l v e d t h e p r e s e n t a t i o n o f t h e t a r g e t l e t t e r f o r 500 msec f o l l o w e d by t h e l e t t e r s t r i n g 1 sec l a t e r . The l e t t e r s t r i n g was p r e s e n t e d b e f o r e t h e t a r g e t i n t h e p o s t c u e t a s k . I n b o t h t a s k s t h e l e t t e r s t r i n g was e x p o s e d f o r a s h o r t d u r a t i o n and masked t o g i v e a n a v e r a g e p e r f o r m a n c e o f 75% c o r r e c t . E i g h t e e n s u b j e c t s were t e s t e d i n t h e e x p e r i m e n t . The d e t a i l s o f t h e me thod , p r o c e d u r e , and r e s u l t s a r e p r e s e n t e d i n Appendix 4 .2

EXPERIMENTS ON LETTER AND WORD PERCEPTION

w n 60

6 3

-

Or t h o g r a p h i c S t r u c t u r e

F i g u r e 4.12 p r e s e n t s p e r c e n t a g e c o r r e c t t a r g e t i d e n t i f i c a t i o n s a s a f u n c t i o n o f t h e f i v e l e v e l s o f o r t h o g r a p h i c s t r u c t u r e . The p r e c u e t a s k v e r s u s t h e p o s t c u e t a s k i s t h e c u r v e p a r a m e t e r . A s c a n be s e e n i n t h e f i g u r e , l a r g e e f f e c t s o f o r t h o g r a p h i c s t r u c t u r e were f o u n d i n b o t h t h e p r e c u e and p o s t c u e t a s k s , a l t h o u g h s l i g h t l y l a r g e r e f f e c t s were found i n t h e p o s t c u e t a s k . The p o s t c u e e x p e r i m e n t r e p l i c a t e s t h e p r e v i o u s s t u d y . The p r e c u e r e s u l t s a r e v e r y s i m i l a r t o t h e p o s t c u e r e s u l t s , a l t h o u g h t h e a t t e n t u a t i o n o f t h e o r t h o g r a p h i c s t r u c t u r e e f f e c t s i n t h e p r e c u e t a s k o v e r t h e p o s t c u e t a s k i s s t a t i s t i c a l l y s i g n i f i c a n t .

The p r i m a r y f o c u s o f t h i s e x p e r i m e n t was t o d e t e r m i n e t h e r e l a t i o n s h i p o f p r e c u e a c c u r a c y p e r f o r m a n c e t o p o s t c u e a c c u r a c y

- Postcue - Precue

50 WORD R-H R-L I-H I-L

I

F i g u r e 4 .12 P e r c e n t a g e c o r r e c t a s a f u n c t i o n o f d i s p l a y t y p e i n t h e p r e c u e and p o s t c u e c o n d i t i o n s o f S t u d y 2.

64 CHAPTER 4

performance. Although t h e i n t e r a c t i o n of t a s k w i t h d i s p l a y c o n d i t i o n s s u g g e s t s a s m a l l e r i n f l u e n c e of o r t h o g r a p h i c s t r u c t u r e i n t h e p r e c u e t h a n p o s t c u e t a s k , t h e r e su l t s a r e s u f f i c i e n t t o r e j e c t t h e h y p o t h e s i s t h a t p r e c u i n g promotes a d r a s t i c r e d u c t i o n i n t h e u s e of o r t h o g r a p h i c s t r u c t u r e . The e f f e c t s of s t r u c t u r e were v e r y s t r o n g f o r bo th p r e c u e and p o s t c u e , and t h e d i f f e r e n c e between t h e two tasks was s m a l l by comparison.

The observed i n t e r a c t i o n of t a s k w i t h d i s p l a y c o n d i t i o n s probably r e f l e c t s d i f f e r e n t memory r e q u i r e m e n t s f o r t h e two t a s k s . I t is r e a s o n a b l e t o e x p e c t t h a t per formance might be poorer i n a p o s t c u e t a s k because t h e n e c e s s i t y of r e t a i n i n g t h e d i s p l a y u n t i l t h e t a r g e t l e t t e r is p r o c e s s e d c o u l d l e a d t o memory l o s s . I t might f u r t h e r be e x p e c t e d t h a t f o r g e t t i n g would be g r e a t e r f o r t h e more p o o r l y - s t r u c t u r e d d i s p l a y s (Baddeley , 1964). Any d i f f e r e n c e s i n o v e r a l l a c c u r a c y between t h e p o s t c u e t h a n i n p r e c u e t a sks a r e n o t meaningfu l because t h e a d a p t i v e a l g o r i t h m endeavored t o m a i n t a i n o v e r a l l a c c u r a c y a t 7 5 % . I n f a c t , s u b j e c t s r e q u i r e d s i g n i f i c a n t l y l o n g e r e x p o s u r e s i n t h e p o s t c u e t h a n t h e p r e c u e t a s k . The l o n g e r d u r a t i o n s f o r t h e . p o s t c u e t a s k a r e c o n s i s t e n t w i t h t h e i d e a t h a t f o r g e t t i n g o c c u r r e d t o a g r e a t e r d e g r e e i n t h e p o s t c u e t h a n i n t h e p r e c u e t a s k .


F i g u r e 4.13 g i v e s t h e p e r c e n t a g e of c o r r e c t i d e n t i f i c a t i o n s of t h e t a r g e t l e t t e r a s a f u n c t i o n of t h e number of s i m i l a r n o n t a r g e t s i n t h e t e s t d i s p l a y . S i m i l a r r e s u l t s were observed i n both t h e p r e c u e and p o s t c u e t a s k s . The o v e r a l l a c c u r a c y d i f f e r e n c e s on t a r g e t and c a t c h t r i a l s f o r bo th t a s k s a r e d i s c u s s e d i n t h e n e x t s e c t i o n . Accuracy d e c r e a s e d w i t h i n c r e a s e s i n t h e number of s i m i l a r n o n t a r g e t s on c a t c h t r i a l s b u t remained r e l a t i v e l y c o n s t a n t on t a r g e t t r i a l s . Al though t h e s i m i l a r i t y e f f e c t s a r e s m a l l e r i n magni tude, t h e c a t c h t r i a l s b u t n o t t h e t a r g e t t r i a l s r e p l i c a t e t h e r e s u l t s of t h e a c c u r a c y t a s k i n S tudy 1. The d e c r e a s e i n a c c u r a c y on c a t c h t r i a l s w i t h i n c r e a s e s i n t h e number of s i m i l a r l e t t e r s a p p e a r s t o be a r e l a t i v e l y r e l i a b l e r e s u l t . I n c o n t r a s t , any e f f e c t of s i m i l a r n o n t a r g e t s on t a r g e t t r i a l s a p p e a r s t o be s m a l l e r i n magni tude and l e s s r e l i a b l e .


T a r g e t V e r s u s Catch T r i a l s

F i g u r e 4 . 1 4 p r e s e n t s t h e p e r c e n t a g e of c o r r e c t t a r g e t i d e n t i f i c a t i o n s f o r t a r g e t and c a t c h t r i a l s i n t h e p r e c u e and p o s t c u e a c c u r a c y t a s k s . R e p l i c a t i n g t h e r e s u l t s o f t h e p r e v i o u s s t u d y , o v e r a l l a c c u r a c y was much g r e a t e r on c a t c h t r i a l s t h a n on t a r g e t t r i a l s i n t h e p o s t c u e t a s k . I n c o n t r a s t , per formance on t a r g e t t r i a l s was more a c c u r a t e t h a n on c a t c h t r i a l s i n t h e p r e c u e a c c u r a c y t a sk . These e f f e c t s c a n be d e s c r i b e d by t h e d e c i s i o n r u l e i n t h e model. For a c c u r a c y t a s k s it is assumed t h a t t h e l e t t e r s t r i n g is r e s o l v e d a s f u l l y as p o s s i b l e w i t h t h e a s s i s t a n c e of o r t h o g r a p h i c s t r u c t u r e . I f none of t h e r e s o l v e d l e t t e r s is t h e t a r g e t , a " y e s " r e s p o n s e is a f u n c t i o n of t h e o b s e r v e r ' s a p r i o r i e x p e c t a t i o n p r o b a b i l i t y t h a t a n u n r e s o l v e d l e t t e r i s a t a r g e t and t h e number of

lJ--- Precue

50 mL 0 1 2 3


F i g u r e 4.13 P e r c e n t a g e c o r r e c t f o r t a r g e t and c a t c h t r i a l s i n ' t h e p r e c u e and p o s t c u e c o n d i t i o n s of S t u d y 2 as a

f u n c t i o n of t h e number of s i m i l a r n o n t a r g e t l e t t e r s i n t h e t e s t s t r i n g .

66

100

90-

I- 80- y 7 0 -

8 80-

w CJ 50 g 100

CHAPTER 4

I I I I I

Precue

... '.. 0 --...-- .-_______ p .... 0

'.. ... %.

Obs Pre Catch Target

....._...

Postcue

unreso lved l e t t e r s . I n te rms of t h e p r e s e n t model, t h e e x p e c t a t i o n parameter E/6 must have d i f f e r e d f o r t h e p r e c u e and p o s t c u e t a sks .

60-

I n f o r m a t i o n P r o c e s s i n q Model

1 I I I

The model was t e s t e d by f i t t i n g i t t o t h e d a t a o f t h e p r e s e n t exper iment . S i x p a r a m e t e r s were e s t i m a t e d f o r e a c h set of 10 means: one E-value, and a s e p a r a t e R-value f o r e a c h o f t h e f i v e d i s p l a y c o n d i t i o n s , e . g . , word, r e g u l a r - h i g h , e tc . The parameter estimates and t h e i r a s s o c i a t e d root mean squared d e v i a t i o n s a r e shown i n Table 4.3 a s P o s t c u e (S tudy 2 ) and Precue (S tudy 2 ) . The model p r o v i d e s a good d e s c r i p t i o n of t h e r e s u l t s of bo th t a s k s .

F i g u r e 4.14 Observed (Obs) and p r e d i c t e d ( P r e ) p e r c e n t a g e c o r r e c t f o r t a r g e t and c a t c h t r i a l s f o r t h e p r e c u e and p o s t c u e c o n d i t i o n s o f S tudy 2 a s a f u n c t i o n of d i s p l a y t y p e .


Not o n l y d o e s t h e f i t of t h e model p r o v i d e s u p p o r t f o r our c o n c e p t u a l i z a t i o n of t h e d e c i s i o n mechanism, b u t t h e parameter v a l u e s a r e meaningfu l . I t is i n t e r e s t i n g t o n o t e t h a t t h e a p p a r e n t b i a s toward "no" r e s p o n s e s i n t h e p o s t c u e t a s k a c t u a l l y r e f l e c t s an a c c u r a t e and unbiased a s s e s s m e n t of t h e e q u a l p r o b a b i l i t y o f t a r g e t and c a t c h t r i a l s . The s u b j e c t s i n t h e p r e c u e t a s k , however, d o e x h i b i t a marked b i a s toward e x p e c t i n g t h e p r e s e n c e of a t a r g e t . Smith e t a l . ( 1 9 7 6 ) have r e p o r t e d s i m i l a r f i n d i n g s i n a precued t a r g e t r e c o g n i t i o n t a sk and s u g g e s t t h a t o b s e r v e r s i n p r e c u e t a s k s may e r r o n e o u s l y i n c o r p o r a t e mask f e a t u r e s i n making t h e i r judgments and t h u s tend t o see t h e t a r g e t i n t h e mask more o f t e n t h a n might be e x p e c t e d . By m a n i p u l a t i n g t h e n a t u r e of t h e m a s k which f o l l o w s t h e d i s p l a y t h e y found a more pronounced e f f e c t when t h e d i s p l a y and mask s h a r e d f e a t u r e s t h a n when t h e y d i d n o t .

Perhaps even more i n t e r e s t i n g t h a n t h e E-parameters were t h e R-values which c o r r e s p o n d t o t h e number of l e t t e r s a c t u a l l y r e s o l v e d f o r each d i s p l a y t y p e . The parameter v a l u e s f o r R a s a f u n c t i o n of d i s p l a y t y p e change s y s t e m a t i c a l l y w i t h o r t h o g r a p h i c s t r u c t u r e a c r o s s both t h e p r e c u e and t h e p o s t c u e exper iments . The l a r g e r e f f e c t of d i s p l a y t y p e f o r t h e p o s t c u e t h a n f o r t h e p r e c u e t a s k is r e f l e c t e d by t h e l a r g e r s p r e a d of t h e R-values f o r t h e p o s t c u e t a s k .

Although t h e i n t e r a c t i o n of d i s p l a y c o n d i t i o n s w i t h t a s k i n t h e p r e s e n t e x p e r i m e n t i m p l i e s t h a t R-values were somewhat d i f f e r e n t i n t h e p r e c u e and p o s t c u e t a s k s , a l l 2 0 d a t a p o i n t s were a l s o f i t w i t h seven p a r a m e t e r s by assuming t h a t a s i n g l e s e t of f i v e R-values and two E-va lues , one f o r p r e c u e and one f o r t h e p o s t c u e , would be s u f f i c i e n t . These p a r a m e t e r s and t h e i r a s s o c i a t e d r o o t mean s q u a r e d d e v i a t i o n s a r e a l s o g i v e n i n Table 4 . 3 a s Combined Data. The p r e d i c t e d r e s u l t s of t h e seven-parameter model a r e shown a l o n g w i t h t h e observed r e s u l t s i n F i g u r e 4.14. The r e a s o n a b l y good d e s c r i p t i o n of t h e r e s u l t shows t h a t t h e combined f i t of t h e two t a s k s is q u i t e a c c e p t a b l e . I n a d d i t i o n , r e d u c i n g t h e number of p a r a m e t e r s from 1 2 t o 7 i n c r e a s e d t h e t o t a l r o o t mean s q u a r e d d e v i a t i o n by less t h a n one p e r c e n t ( f rom 1 . 6 % t o 2 . 5 % ) .

STUDY 3 : MIXED-CASE

The r e s u l t s of t h e comparison between p r e c u e and p o s t c u e t a s k s i n d i c a t e s t h a t p r e c u i n g a l o n e is n o t a s u f f i c i e n t c o n d i t i o n t o c a u s e a d r a s t i c r e d u c t i o n i n t h e use of

CHAPTER A

o r t h o g r a p h i c s t r u c t u r e , a t l e a s t i n a c c u r a c y tasks . I t s t i l l might be t h e c a s e , however, t h a t p r e c u i n g i n t h e RT t a s k i n which u n l i m i t e d viewing time i n s u r e s t h a t a l l o f t h e f e a t u r e s of t h e d i s p l a y c a n be e x t r a c t e d promotes a f e a t u r e d e t e c t i o n s t r a t e g y . The n e x t exper iment a d d r e s s e s t h e issue of whether o r n o t d i s c o u r a g i n g a f e a t u r e d e t e c t i o n s t r a t e g y w i l l promote t h e u t i l i z a t i o n of o r t h o g r a p h i c s t r u c t u r e i n t h e r e s o l u t i o n of t h e t e s t s t r i n g .

Much o f t h e i n t u i t i v e a p p e a l of t h e f e a t u r e d e t e c t i o n s t r a t e g y is t h e i d e a t h a t r e c o g n i t i o n of t h e t a r g e t l e t t e r could O C C U K on t h e b a s i s of o n l y a few f e a t u r e s and w i t h o u t t h e n e c e s s i t y of f u l l y r e s o l v i n g a l l f e a t u r e s o f t h e l e t t e r . The e f f e c t i v e n e s s of t h i s s t r a t e g y would be reduced i f t h e s p e c i f i c v i s u a l c o n f i g u r a t i o n of t h e t a r g e t , and t h u s t h e e x a c t form o f t h e c r i t i c a l f e a t u r e s , c o u l d n o t be p r e d i c t e d . One p r o c e d u r e would be t o have t h e l e t t e r s t r i n g appear i n s e v e r a l d i f f e r e n t f o n t s w i t h t h e f o n t of t h e t a r g e t a p p e a r i n g on a g i v e n tes t t r i a l be ing u n p r e d i c t a b l e . The p r e s e n t e x p e r i m e n t approximated t h i s method by p r e s e n t i n g t h e d i s p l a y s p r i n t e d h a l f i n uppercase l e t t e r s and h a l f i n l o w e r c a s e . Thus, t h e l e t t e r c a s e of t h e t a r g e t l e t t e r was n o t c o m p l e t e l y p r e d i c t a b l e . Whereas it might s t i l l be p o s s i b l e t o d e t e c t f e a t u r e s f o r u p p e r c a s e and lowercase l e t t e r s s i m u l t a n e o u s l y , t h e e x t r a e f f o r t s h o u l d reduce t h e e f f e c t i v e n e s s of t h e f e a t u r e d e t e c t i o n s t r a t e g y . T h e r e f o r e , i t is p r e d i c t e d t h a t i f t h e f e a t u r e d e t e c t i o n s t r a t e g y i s t h e cause of t h e small e f f e c t o f o r t h o g r a p h i c s t r u c t u r e i n a p r e c u e RT t a s k , t h e n a s i g n i f i c a n t l y l a r g e r e f f e c t should be observed i n t h e mixed-case c o n d i t i o n , where t h e e f f e c t i v e n e s s of t h e f e a t u r e d e t e c t i o n s t r a t e g y w i l l be d i m i n i s h e d .

T a y l o r , M i l l e r , and J u o l a (1977) have r e p o r t e d t h a t mixing c a s e s d i s r u p t s t h e u t i l i z a t i o n of o r t h o g r a p h i c s t r u c t u r e i n word p e r c e p t i o n . The amount of d i s r u p t i o n was found t o be a m o n o t o n i c a l l y i n c r e a s i n g f u n c t i o n of t h e number of t r a n s i t i o n s between c a s e s i n t h e s t r i n g t o be p e r c e i v e d . To minimize t h e d i s r u p t i v e i n f l u e n c e of c a s e t r a n s i t i o n s on t h e u t i l i z a t i o n of o r t h o g r a p h i c S t K U C t U K e , o n l y a s i n g l e t r a n s i t i o n between t h e t h i r d and f o u r t h l e t t e r s was used i n t h i s exper iment .

The p r o c e d u r e was t h e same as t h e e a r l i e r r e a c t i o n t i m e exper iment w i t h t h e f o l l o w i n g m o d i f i c a t i o n s . The t a r g e t l e t t e r was p r e s e n t e d a t t h e beginning of each t r i a l i n b o t h i t s uppercase and l o w e r c a s e forms. On each t r i a l , t h e t e s t s t r i n g was p r e s e n t e d s o t h a t e i t h e r t h e f i r s t t h r e e l e t t e r s were i n uppercase and t h e l a s t t h r e e l e t t e r s i n lowercase or t h e


- 0

I 750-

I

w z I- 700-

5 I- 8 650-

o p p o s i t e OCCUKKed. The d e t a i l s of t h e method, p r o c e d u r e , and r e s u l t s a r e p r e s e n t e d i n Appendix 4.3.


F i g u r e 4.15 p r e s e n t s t h e mean r e a c t i o n times i n t h e t a s k a s a f u n c t i o n of o r t h o g r a p h i c s t r u c t u r e . There was o n l y a 7 msec advantage of words over r e g u l a r - h i g h pseudowords. The 30 msec advantage of r e g u l a r o v e r i r r e g u l a r s t r i n g s was s i g n i f i c a n t a s was t h e 1 4 msec a d v a n t a g e of s t r i n g s h i g h i n p o s i t i o n a l f r e q u e n c y r e l a t i v e t o s t r i n g s low i n p o s i t i o n a l f r e q u e n c y .

By mixing t h e c a s e s of t h e l e t t e r s i n t h e p r e s e n t s t u d y , t h e o v e r a l l e f f e c t of o r t h o g r a p h i c s t r u c t u r e i n c r e a s e d from 34 msec i n t h e r e a c t i o n t i m e exper iment o f Study 1 t o 5 1 msec i n

800, , I 1 I I

F i g u r e 4.15

0 Catch

I-H I-L

R e a c t i o n time and p e r c e n t a g e c o r r e c t a s of d i s p l a y t y p e i n S tudy 3: Nixed-Case

a f u n c t i o n

70 CHAPTER 4

t h e p r e s e n t mixed-case r e a c t i o n t i m e s t u d y . Mixing t h e c a s e s i n c r e a s e d t h e o v e r a l l r e a c t i o n t i m e by a b o u t 120 msec. I t i s , t h e r e f o r e , n e c e s s a r y t o ask whether t h e 17 msec i n c r e a s e f o r t h e e f f e c t o f o r t h o g r a p h i c s t r u c t u r e is meaningfu l . I f w e c a n assume t h a t t h e 120 msec i n c r e a s e i n RTs t o mixed-case d i s p l a y s r e p r e s e n t s t h e a d d i t i o n a l v i s u a l p r o c e s s i n g r e q u i r e d , t h e n t h e 17 msec i n c r e a s e i n o r t h o g r a p h i c s t r u c t u r e e f f e c t s may p r o v i d e a meaningfu l e v a l u a t i o n of t h e i n f l u e n c e of o r t h o g r a p h i c s t r u c t u r e i n t h e RT t a s k . The i n c r e a s e i n t h e e f f e c t o f o r t h o g r a p h i c s t r u c t u r e r e l a t i v e t o t h e a d d i t i o n a l v i s u a l p r o c e s s i n g r e q u i r e d is 1 4 % . Even 1 4 % , however, may b e a n u n d e r e s t i m a t e of t h e s i z e of t h e e f f e c t o f o r t h o g r a p h i c s t r u c t u r e s i n c e t h e a d d i t i o n a l 120 msec of p r o c e s s i n g r e q u i r e d by mixed-case s t i m u l i may i n c l u d e a d d i t i o n a l t ime needed f o r t h e comparison p r o c e s s when t h e t a r g e t c a n occur i n e i t h e r uppercase o r l o w e r c a s e .


I f mixing t h e c a s e s a t t e n u a t e d t h e f e a t u r e d e t e c t i o n s t r a t e g y t h e n w e would e x p e c t a d e c r e a s e i n t h e e f f e c t s o f t h e number of s i m i l a r n o n t a r g e t l e t t e r s i n t h e d i s p l a y on c a t c h t r i a l s . The s i m i l a r i t y a n a l y s e s a r e c o m p l i c a t e d by t h e m i x t u r e o f upper- and l o w e r c a s e s i n t h e s t r i n g . Because t h e c o n f u s i o n s e t s were d e r i v e d from c o n f u s i o n s o f lowercase l e t t e r s , a p p l i c a t i o n of these c o n f u s i o n s e t s t o t h e d a t a w i t h o u t r e g a r d t o l e t t e r c a s e s would n o t be a p p r o p r i a t e . T h e r e f o r e , a r e s t r i c t e d s i m i l a r i t y a n a l y s i s was done by examining o n l y t h e lowercase l e t t e r s i n t h e d i s p l a y s t r i n g s . When t h i s was done , t h e r e were o n l y two v i a b l e s i m i l a r i t y c a t e g o r i e s : z e r o and one s i m i l a r l e t t e r s . For t a r g e t t r i a l s t h e means were 658 and 658 msec f o r t h e zero and one c a t e g o r i e s r e s p e c t i v e l y . For c a t c h t r i a l s t h e s e means were 731 and 756 msec. These r e s u l t s r e p l i c a t e t h e RT t a s k i n S tudy 1; RTs f o r c a t c h t r i a l s b u t n o t t a r g e t t r i a l s i n c r e a s e w i t h t h e number of s i m i l a r n o n t a r g e t s i n t h e t e s t s t r i n g . Based on t h e s i m i l a r i t y a n a l y s e s , mixing t h e c a s e s d i d n o t appear t o a t t e n t u a t e t h e f e a t u r e d e t e c t i o n s t r a t e g y . The exper iment p r o v i d e s mixed e v i d e n c e f o r t h e h y p o t h e s i s t h a t a f e a t u r e d e t e c t i o n s t r a t e g y o c c u r s i n precue RT t a s k s . The e f f e c t o f o r t h o g r a p h i c s t r u c t u r e was i n c r e a s e d somewhat by mixing t h e c a s e s and i t might have been concluded t h a t use of a f e a t u r e d e t e c t i o n s t r a t e g y was prec luded and more use made of o r t h o g r a p h i c con tex t . However, t h e f a i l u r e t o a t t e n u a t e s i m i l a r i t y e f f e c t s p r e c l u d e s any f i r m c o n c l u s i o n a b o u t t h e f e a t u r e d e t e c t i o n s t r a t e g y . E i t h e r t h e s u b j e c t s


p e r s i s t e d i n t h e now more d i f f i c u l t t a s k of l o o k i n g f o r f e a t u r e matches i n t w o - l e t t e r cases o r f e a t u r e d e t e c t i o n is n o t t h e c o r r e c t e x p l a n a t i o n f o r t h e r e s u l t s of e i t h e r of t h e two e x p e r i m e n t s .

STUDY 4 : LIMITED V I E W I N G TIME

I n a n o t h e r a t t e m p t t o d i s c o u r a g e t h e f e a t u r e d e t e c t i o n s t r a t e g y , s u b j e c t s were not g i v e n u n l i m i t e d viewing t i m e i n t h e r e a c t i o n time t a s k of t h e p r e s e n t e x p e r i m e n t . I n t h e RT t a s k ( S t u d i e s 1 and 3 ) , t h e s u b j e c t s were g i v e n u n l i m i t e d time and hence a l l of t h e v i s u a l i n f o r m a t i o n n e c e s s a r y f o r d e t a i l e d p e r c e p t u a l r e s o l u t i o n o f t h e s t i m u l u s d i s p l a y s . I n t h e a c c u r a c y task ( S t u d i e s 1 and 2 ) , viewing time was s h o r t e n e d so t h a t v i s u a l i n f o r m a t i o n was i n a d e q u a t e t o c l e a r l y r e s o l v e a l l of t h e d i s p l a y . D e c i s i o n s a t a f e a t u r e d e t e c t i o n l e v e l may depend on t h e c e r t a i n t y t h a t a l l t h e v i s u a l i n f o r m a t i o n w i l l be r e s o l v e d . I f so , l i m i t i n g viewing time i n t h e RT t a s k s h o u l d i n c r e a s e t h e s i z e of o r t h o g r a p h i c s t r u c t u r e e f f e c t s . S tudy 4 t e s t e d t h i s h y p o t h e s i s by g i v i n g t h e s u b j e c t s t h e d i s p l a y f o r a l i m i t e d time. However, i t was n o t p o s s i b l e t o l i m i t v iewing time a s s e v e r e l y a s i n t h e p r e v i o u s a c c u r a c y t a s k s and s t i l l m a i n t a i n e r r o r r a t e s low enough t o p e r m i t meaningfu l i n t e r p r e t a t i o n o f RTs . S tudy 4 was a h y b r i d ; v iewing time was s h o r t e n e d and e r r o r r a t e s a l lowed t o r i s e b u t n e i t h e r was t a k e n t o e x t r e m e s .

The s t i m u l i and a p p a r a t u s were t h e same a s i n t h e r e a c t i o n time e x p e r i m e n t o f S tudy 1. Rather t h a n l e a v i n g t h e s t i m u l u s d i s p l a y on u n t i l t h e s u b j e c t responded, t h e d i s p l a y was p r e s e n t e d f o r o n l y 2 0 0 msec and fo l lowed immedia te ly by a masking s t i m u l u s . On t h e b a s i s of t h e p i l o t work, t h i s d u r a t i o n was chosen because i t n o t o n l y l i m i t e d viewing time b u t a l s o gave t h e s u b j e c t s u f f i c i e n t v i s u a l i n f o r m a t i o n t o respond r e a s o n a b l y a c c u r a t e l y . S i x t e e n s u b j e c t s were chosen from t h e same p o p u l a t i o n a s t h e e a r l i e r s t u d i e s . A l l o t h e r d e t a i l s a r e g i v e n i n Appendix 4 . 4 .


F i g u r e 4.16 p r e s e n t s t h e r e a c t i o n time f o r c o r r e c t r e s p o n s e s as a f u n c t i o n o f o r t h o g r a p h i c s t r u c t u r e . A s can be seen i n t h e f i g u r e , no e f f e c t s o f o r t h o g r a p h i c s t r u c t u r e were observed . Although o r t h o g r a p h i c s t r u c t u r e d i d n o t have a s i g n i f i c a n t e f f e c t on r e a c t i o n time, i t d i d a f f e c t

1 2 CHAPTER 4

0 0

a c c u r a c y . The small d i f f e r e n c e s i n a c c u r a c y as a f u n c t i o n of o r t h o g r a p h i c s t r u c t u r e were found t o be s t a t i s t i c a l l y s i g n i f i c a n t . By l i m i t i n g t h e d i s p l a y d u r a t i o n , i t a p p e a r s t h a t t h e e x p e r i m e n t b e g i n s t o approximate a n a c c u r a c y e x p e r i m e n t , and t h e s m a l l e r e f f e c t s o f o r t h o g r a p h i c s t r u c t u r e c a n s i m p l y be a t t r i b u t e d t o t h e o v e r a l l h i g h l e v e l of per formance .


Although a c c u r a c y v a r i e d s l i g h t l y w i t h d i f f e r e n c e s i n o r t h o g r a p h i c s t r u c t u r e , t h e r e were no s i g n i f i c a n t changes i n a c c u r a c y as a f u n c t i o n of t h e number of s i m i l a r n o n t a r g e t s i n t h e t e s t d i s p l a y . I n c o n t r a s t , t h e RTs c o n t i n u e d t o r e v e a l t h e c o n s i s t e n t f i n d i n g t h a t RTs on c a t c h t r i a l s i n c r e a s e d w i t h i n c r e a s e s i n t h e number of s i m i l a r n o n t a r g e t s whereas RTs on t a r g e t t r i a l s showed no e f f e c t . A c c o r d i n g l y , t h e r e s u l t s show

7001 1 I I I

F i g u r e 4 . 1 6 R e a c t i o n t i m e and p e r c e n t a g e c o r r e c t a s a f u n c t i o n of d i s p l a y t y p e i n S tudy 4 : Limi ted Viewing Time.


t h a t an o r t h o g r a p h i c s t r u c t u r e e f f e c t i n terms of r e s p o n s e a c c u r a c y c a n c o e x i s t w i t h a s i m i l a r i t y e f f e c t on RT. T h i s r e s u l t r e v e a l s t h a t a f e a t u r a l d e t e c t i o n s t r a t e g y a s indexed by s i g n i f i c a n t s i m i l a r i t y e f f e c t s d o e s n o t p r e c l u d e a s i g n i f i c a n t c o n t r i b u t i o n of o r t h o g r a p h i c s t r u c t u r e . I t a p p e a r s t h a t o r t h o g r a p h i c s t r u c t u r e e f f e c t s can be found i n both a c c u r a c y and RT measures , b u t t h a t RT e f f e c t s a r e n o t a s r e l i a b l e o r s e n s i t i v e a s a c c u r a c y e f f e c t s .

T a r g e t V e r s u s Catch T r i a l s

T a r g e t t r i a l s ( 5 6 3 msec) were responded t o more q u i c k l y t h a n c a t c h t r i a l s ( 6 3 5 msec) whereas t h e r e was no s i g n i f i c a n t d i f f e r e n c e between t h e two k i n d s of t r i a l s i n t e r m s o f r e s p o n s e a c c u r a c y .

D i s c u s s i o n

The r e s u l t s d i s c o n f i r m t h e h y p o t h e s i s t h a t l i m i t i n g viewing time might i n c r e a s e t h e i n f l u e n c e of o r t h o g r a p h i c s t r u c t u r e on RT. R e a c t i o n times were found t o be uni form o v e r c o n d i t i o n s . However, t h e p a t t e r n of e r r o r r a t e s r e f l e c t e d t h e i n f l u e n c e of s t r u c t u r e . L i m i t i n g v i s u a l i n f o r m a t i o n c l e a r l y h a s a n i n f l u e n c e on a c c u r a c y , and t h i s i n f l u e n c e is modulated by t h e p r e s e n c e of o r t h o g r a p h i c s t r u c t u r e . A s f o r t h e u n u s u a l l y uniform RTs, t h e y might r e f l e c t t h e s u b j e c t s having e s t a b l i s h e d and m a i n t a i n e d a se l f - imposed r e s p o n s e d e a d l i n e . T h e r e f o r e , any e f f e c t o f o r t h o g r a p h i c s t r u c t u r e would be r e f l e c t e d o n l y on per formance a c c u r a c y .

STUDY 5 : SPEEDED RT TASK WITH GOOD VISUAL INFORMATION

Study 5 t e s t s between two h y p o t h e s e s of t h e d i f f e r e n c e s i n t h e s e n s i t i v i t y o f t h e a c c u r a c y and RT t a s k s t o o r t h o g r a p h i c s t r u c t u r e . According t o t h e f i r s t h y p o t h e s i s , t h e d i f f e r e n c e between t h e a c c u r a c y and RT t a s k s c o u l d be due t o a t r a d e - o f f between t h e c o n t r i b u t i o n of s t i m u l u s i n f o r m a t i o n and o r t h o g r a p h i c s t r u c t u r e i n t h e t a s k . There is abundant s t i m u l u s i n f o r m a t i o n i n t h e RT t a s k , and t h e r e f o r e , t h e r e may be v e r y l i t t l e o p p o r t u n i t y f o r knowledge a b o u t o r t h o g r a p h i c s t r u c t u r e t o c o n t r i b u t e t o per formance . I n t h e a c c u r a c y t a s k , on t h e o t h e r hand, t h e s t i m u l u s i n f o r m a t i o n is i n a d e q u a t e and c o n s e q u e n t l y , t h e r e i s c o n s i d e r a b l e o p p o r t u n i t y f o r

74 CHAPTER 4

o r t h o g r a p h i c knowledge t o e x e r t an i n f l u e n c e . T h i s e x p l a n a t i o n i s c l e a r l y d i f f e r e n t from t h e f e a t u r e d e t e c t i o n s t r a t e g y d i s c u s s e d e a r l i e r . I n t h e c a s e of a f e a t u r e d e t e c t i o n s t r a t e g y , t h e r e is a n o p p o r t u n i t y f o r o r t h o g r a p h i c s t r u c t u r e t o e x e r t an i n f l u e n c e b u t a d e c i s i o n a b o u t t h e l e t t e r s t r i n g is made w i t h o u t u t i l i z i n g t h e s t r u c t u r e . By c o n t r a s t , i n t h e c a s e of a t r a d e - o f f between v i s u a l i n f o r m a t i o n and o r t h o g r a p h i c s t r u c t u r e , t h e comple te v i s u a l i n f o r m a t i o n p r e c l u d e s a c o n t r i b u t i o n of o r t h o g r a p h i c s t r u c t u r e .

Evidence f o r t h e t r a d e - o f f between t h e c o n t r i b u t i o n s of s t i m u l u s i n f o r m a t i o n and knowledge comes from a number of RT e x p e r i m e n t s t h a t have i n d e p e n d e n t l y v a r i e d s t i m u l u s q u a l i t y and knowledge ( c . f . , Meyer, S c h v a n e v e l d t , & Ruddy, 1 9 7 5 ) . M a S S a K O ,

J o n e s , Lipscomb, and Scholz ( 1 9 7 8 ) , f o r example, had s u b j e c t s name a word a s q u i c k l y a s p o s s i b l e . The word was e i t h e r p r e s e n t e d u p r i g h t or was r o t a t e d 1 8 0 d e g r e e s i n t h e p i c t u r e p l a n e . The word was preceded by a word "b lank" or by a c a t e g o r y pr ime, which was t h e s u p e r o r d i n a t e c a t e g o r y name of t h e t e s t word. Pr iming w i t h t h e c a t e g o r y name i s t h e advance knowledge i n t h e task and it might b e e x p e c t e d t o f a c i l i t a t e p r o c e s s i n g of t h e t e s t word. T h e r e f o r e , RTs s h o u l d be f a s t e r on primed t h a n unprimed t r i a l s . Of c o u r s e , r o t a t i n g t h e t e s t words s h o u l d slow down t h e naming r e s p o n s e s i n c e t h e s t i m u l u s i n f o r m a t i o n is degraded; we a r e n o t used t o s e e i n g and r e a d i n g r o t a t e d t e x t . The r e s u l t s showed t h a t pr iming had a n o n s i g n i f i c a n t 7 msec f a c i l i t a t i o n when t h e words were p r e s e n t e d u p r i g h t b u t a s i g n i f i c a n t 1 2 1 msec e f f e c t when words were r o t a t e d 1 8 0 d e g r e e s . S i m i l a r r e s u l t s were found i n a l e x i c a l d e c i s i o n t a s k . With a good q u a l i t y t e s t d i s p l a y , p r iming had e s s e n t i a l l y no e f f e c t : g i v e n a poor q u a l i t y d i s p l a y , advance knowledge f a c i l i t a t e d per formance . I n t h e p r e s e n t e x p e r i m e n t s , g i v e n a good q u a l i t y d i s p l a y i n t h e RT t a s k , o r t h o g r a p h i c s t r u c t u r e had a small e f f e c t ; w i t h a poor q u a l i t y d i s p l a y i n t h e a c c u r a c y t a s k , o r t h o g r a p h i c s t r u c t u r e had a l a r g e e f f e c t .

The second h y p o t h e s i s is t h a t t h e c o n t r i b u t i o n of o r t h o g r a p h i c s t r u c t u r e i s s i m i l a r i n t h e a c c u r a c y and RT t a s k s b u t t h e a c c u r a c y t a s k a l l o w s a more d i r e c t measure of t h e s i z e of t h i s c o n t r i b u t i o n . I n t h e RT t a s k where t h e v i s u a l d i s p l a y i s c l e a r l y v i s i b l e and viewing time u n l i m i t e d , t h e l e t t e r s t r i n g is r e s o l v e d v e r y q u i c k l y and t h e time t o r e s o l v e t h e l e t t e r s may be s m a l l r e l a t i v e t o t h e times f o r t h e remain ing p r o c e s s e s of s e a r c h , compar ison , d e c i s i o n , and r e s p o n s e s e l e c t i o n . Thus, t h e f a c i l i t a t i n g e f f e c t o f o r t h o g r a p h i c s t r u c t u r e might be l a r g e i n terms of t h e time s a v i n g s f o r


v i s u a l r e s o l u t i o n , b u t s m a l l r e l a t i v e t o t h e o v e r a l l RT. For example, a 20 msec e f f e c t of s t r u c t u r e when v i s u a l r e s o l u t i o n t a k e s 100 msec w i t h o u t any c o n t r i b u t i o n of s t r u c t u r e would expand a 500 msec RT by o n l y 4 % . Even though t h i s 20% e f f e c t on v i s u a l r e s o l u t i o n is i m p o r t a n t , i t would appear s m a l l r e l a t i v e t o t h e o v e r a l l RT. By c o n t r a s t , t h e v i s u a l i n f o r m a t i o n i n t h e a c c u r a c y t a s k is l i m i t e d and e r r o r s a r e a d i r e c t consequence of l i m i t a t i o n s i n v i s u a l r e s o l u t i o n . Accord ingly , a f a c i l i t a t i o n of v i s u a l r e s o l u t i o n w i l l be more d i r e c t l y r e f l e c t e d i n a n improvement i n t a s k ac- c u r a c y . According t o t h i s h y p o t h e s i s , even though o r t h o g r a p h i c s t r u c t u r e c o n t r i b u t e s r o u g h l y t h e same a d d i t i o n a l i n f o r m a t i o n i n both t h e RT and a c c u r a c y t a s k s , t h e s i z e of RT e f f e c t w i l l appear s m a l l r e l a t i v e t o t h e a c c u r a c y e f f e c t .

I n o r d e r t o t e s t between t h e s e two h y p o t h e s e s , a n exper iment was c a r r i e d o u t i n which t h e r e a d e r would have good q u a l i t y v i s u a l i n f o r m a t i o n b u t a c c u r a c y r a t h e r t h a n RT would be t h e p r i m a r y dependent v a r i a b l e . ~f t h e c o n t r i b u t i o n of o r t h o g r a p h i c s t r u c t u r e is i n v e r s e l y r e l a t e d t o t h e q u a l i t y of t h e v i s u a l i n f o r m a t i o n a s p r e d i c t e d by t h e t r a d e - o f f h y p o t h e s i s , t h e n a v e r y s m a l l e f f e c t of s t r u c t u r e s h o u l d be a p p a r e n t on a c c u r a c y . However, i f t h e c o n t r i b u t i o n of s t r u c t u r e is independent of t h e q u a l i t y of t h e v i s u a l i n f o r m a t i o n and a c c u r a c y i s s imply a more d i r e c t measure , t h e n t h e t y p i c a l l a r g e e f f e c t s of s t r u c t u r e on a c c u r a c y s h o u l d be o b s e r v e d . Given t h a t a c c u r a c y is now t i e d t o 75% c o r r e c t , i t s h o u l d be a more d i r e c t index of t h e c o n t r i b u t i o n of s t r u c t u r e . T h e r e f o r e , t h e p r e s e n t e x p e r i m e n t p r o v i d e s a t e s t between t h e two h y p o t h e s e s w i t h o u t having t o compare a c c u r a c y e f f e c t s t o RT e f f e c t s . A m o d i f i c a t i o n of a speed-accuracy t r a d e - o f f paradigm which r e q u i r e s a speeded r e a c t i o n i n s y n c h r o n i z a t i o n w i t h a s i g n a l e v e n t (Reed, 1973) was used t o keep a v e r a g e per formance a t 75% c o r r e c t . The s u b j e c t s were g i v e n t h e t a r g e t l e t t e r fo l lowed by t h e d i s p l a y and were r e q u i r e d t o respond a s n e a r l y i n synchrony w i t h t h e o f f s e t of t h e d i s p l a y a s p o s s i b l e . Using a n a d a p t i v e a l g o r i t h m , a d i s p l a y d u r a t i o n was c a l c u l a t e d t o keep t h e s u b j e c t ' s o v e r a l l a c c u r a c y a t 75%. Because t h e d u r a t i o n of t h e d i s p l a y averaged around 500 msec, i t seems S a f e t o assume t h a t t h e s u b j e c t s have good q u a l i t y s t i m u l u s i n f o r m a t i o n . T h e r e f o r e , t h e t r a d e - o f f h y p o t h e s i s p r e d i c t s no e f f e c t of s t r u c t u r e whereas t h e h y p o t h e s i s t h a t a c c u r a c y i s a more d i r e c t measure t h a n RT p r e d i c t s a l a r g e e f f e c t O f

s t ruc ture .

76 CHAPTER 4

Procedure

Eleven s t u d e n t s , s e l e c t e d from t h e same p o p u l a t i o n as t h o s e i n t h e e a r l i e r e x p e r i m e n t s , were t e s t e d on a s i n g l e day. A t a r g e t l e t t e r was p r e s e n t e d f o r 5 0 0 msec and fo l lowed by t h e t e s t d i s p l a y a f t e r an i n t e r v a l of 2 5 0 msec. The t e s t d i s p l a y d u r a t i o n was modi f ied e v e r y 20 t r i a l s t h r o u g h o u t t h e e x p e r i m e n t t o keep o v e r a l l per formance a t 75% c o r r e c t . S u b j e c t s were i n s t r u c t e d t o respond as c l o s e t o t h e s t i m u l u s o f f s e t as p o s s i b l e and t h e y were g i v e n feedback on t h i s t a s k a f t e r e a c h b lock of 2 0 t r i a l s . E s s e n t i a l l y , s u b j e c t s s imply l e a r n e d t o m a i n t a i n a p a r t i c u l a r r e s p o n s e time, n o t t o respond t o t h e o f f s e t of t h e d i s p l a y i t s e l f . None of t h e s u b j e c t s had any d i f f i c u l t y w i t h t h i s t a s k . D e t a i l s o f t h e method, p r o c e d u r e , and r e s u l t s a r e g i v e n i n Appendix 4.5.

550 -

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8 0 70

WORD R-H R-L I-H I-L

F i g u r e 4.17 R e a c t i o n time and p e r c e n t a g e c o r r e c t as a f u n c t i o n o f d i s p l a y t y p e i n S tudy 5: Speeded RT Task w i t h Good V i s u a l I n f o r m a t i o n .



F i g u r e 4.17 p r e s e n t s t h e c o r r e c t r e a c t i o n times and r e s p o n s e a c c u r a c y a s a f u n c t i o n of o r t h o g r a p h i c s t r u c t u r e ; t a r g e t and c a t c h t r i a l s a r e p l o t t e d s e p a r a t e l y . There was a 1 5 msec e f f e c t of o r t h o g r a p h i c s t r u c t u r e on c o r r e c t r e a c t i o n times and a 1 . 9 % e f f e c t on a c c u r a c y . T h e r e f o r e , no s t r o n g e f f e c t of o r t h o g r a p h i c s t r u c t u r e on e i t h e r RT o r a c c u r a c y was p r e s e n t . T h i s r e s u l t is c o n s i s t e n t w i t h t h e t r a d e - o f f h y p o t h e s i s whereby t h e c o n t r i b u t i o n of o r t h o g r a p h i c s t r u c t u r e is i n v e r s e l y r e l a t e d t o t h e q u a l i t y of t h e v i s u a l i n f o r m a t i o n i n t h e t e s t s t r i n g .

STUDY 6: SPEEDED RT TASK WITH POOR VISUAL INFORMATION

The speeded RT t a sk i n S tudy 5 p r o v i d e d e v i d e n c e t h a t t h e a c c u r a c y t a sk may g i v e l a r g e r e f f e c t s t h a n d o e s t h e RT t a s k because of t h e p o o r e r q u a l i t y o f t h e v i s u a l i n f o r m a t i o n i n t h e a c c u r a c y t a s k . A c c o r d i n g l y , g i v i n g good q u a l i t y i n f o r m a t i o n i n t h e speeded RT t a s k shows no e f f e c t of o r t h o g r a p h i c s t r u c t u r e on r e s p o n s e a c c u r a c y . Before a c c e p t i n g t h i s c o n c l u s i o n , i t is i m p o r t a n t t o v e r i f y whether t h e speed-accuracy paradigm t h a t was used is i t s e l f s e n s i t i v e t o o r t h o g r a p h i c s t r u c t u r e . I t could be t h e c a s e t h a t t h e p e r c e p t u a l s t a g e g o e s t o c o m p l e t i o n i n a l l c o n d i t i o n s and t h a t e r r o r s are s imply a f u n c t i o n of l a t e r s t a g e s such a s r e s p o n s e s e l e c t i o n . Any small d i f f e r e n c e s i n c o m p l e t i o n times of t h e p e r c e p t u a l s t a g e as a f u n c t i o n of o r t h o g r a p h i c s t r u c t u r e may n o t s i g n i f i c a n t l y i n f l u e n c e t h e a c c u r a c y o f l a t e r s t a g e s of p r o c e s s i n g , and t h e r e f o r e , t h e d i f f e r e n c e s i n t h e p e r c e p t u a l s t a g e would n o t be r e f l e c t e d i n e i t h e r r e s p o n s e a c c u r a c y o r r e a c t i o n t i m e . To t e s t t h e s s n s i t i v i t y o f t h e speeded R T t a s k , i t is n e c e s s a r y t o r e p l i c a t e t h e t a s k w i t h poor q u a l i t y i n f o r m a t i o n . I f t h e t a s k is s e n s i t i v e and t h e e f f e c t of s t r u c t u r e is i n v e r s e l y r e l a t e d t o s t i m u l u s q u a l i t y , t h e n s i g n i f i c a n t e f f e c t s s h o u l d be found. I f t h e t a s k i s i n s e n s i t i v e t o t h e p e r c e p t u a l s t a g e , however, no e f f e c t of o r t h o g r a p h i c s t r u c t u r e should be observed .

A s d i s c u s s e d p r e v i o u s l y , MaSSaL-0 e t a l . (1978) degraded t h e q u a l i t y o f test s t r i n g s by r o t a t i n g them 180 d e g r e e s i n t h e p i c t u r e p l a n e . Fol lowing t h i s approach , t h e speeded RT t a sk was r e p l i c a t e d w i t h t h e test s t r i n g s r o t a t e d i n t h e same manner. Given t h a t r o t a t i o n l o w e r s t h e q u a l i t y of t h e v i s u a l

78 CHAPTER 4

650

600

550

i n f o r m a t i o n , a n e f f e c t of o r t h o g r a p h i c s t r u c t u r e s h o u l d be observed i f t h e speeded RT t a s k i s s e n s i t i v e t o p e r c e p t u a l d i f f e r e n c e s due t o t h e o r t h o g r a p h i c s t r u c t u r e . I f t h e t a s k i t s e l f is i n s e n s i t i v e t h e n no e f f e c t s of s t r u c t u r e s h o u l d be observed .

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Procedure

The speeded RT t a s k i n S tudy 5 was r e p l i c a t e d e x a c t l y w i t h a new g r o u p of s t u d e n t s e x c e p t t h a t t h e t e s t s t r i n g s were r o t a t e d 18B d e g r e e s i n t h e p i c t u r e p l a n e r a t h e r t h a n p r e s e n t e d u p r i g h t . The t a r g e t l e t t e r was s t i l l p r e s e n t e d u p r i g h t . The d e t a i l s of t h e method, p r o c e d u r e , and r e s u l t s a r e p r e s e n t e d i n Appendix 4.6.


F i g u r e 4.18 p r e s e n t s t h e c o r r e c t r e a c t i o n times and accuracy performance. There was a 7 msec e f f e c t of s t r u c t u r e

700 - Catch

*------*Target

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0 Catch

O m 8 WORD R-H R-L I-H I-L

F i g u r e 4.18 Reac t ion time and p e r c e n t a g e c o r r e c t as a f u n c t i o n of d i s p l a y t y p e i n S tudy 6 : Speeded RT Task w i t h Poor V i s u a l I n f o r m a t i o n .


on c o r r e c t r e a c t i o n times and a 1 . 7 % e f f e c t on r e s p o n s e a c c u r a c y . The r e s u l t s o f t h i s e x p e r i m e n t a r e a d i r e c t r e p l i c a t i o n of t h o s e i n t h e p r e v i o u s speeded RT t a s k and t h e r e f o r e p r o v i d e s t r o n g e v i d e n c e f o r t h e i d e a t h a t t h e speeded RT t a s k is i n s e n s i t i v e t o p e r c e p t u a l d i f f e r e n c e s due t o t h e o r t h o g r a p h i c s t r u c t u r e . Before t h i s c o n c l u s i o n is a c c e p t e d , however, i t w i l l be n e c e s s a r y t o v e r i f y t h a t o r t h o g r a p h i c s t r u c t u r e e f f e c t s d o occur w i t h r o t a t e d t e s t s t r i n g s i n o t h e r t a s k s . I n o r d e r t o have a d i r e c t l y a n a l o g o u s s i t u a t i o n t o t h e speeded RT t a s k s , t h e t a s k m u s t keep t h e t e s t s t r i n g i n view d u r i n g t h e p r o c e s s i n g p e r i o d . T h e r e f o r e , h i g h a c c u r a c y i s t o be e x p e c t e d and RT m u s t be t h e d e p e n d e n t measure.

STUDY 7 : HIGH-ACCURACY RT TASK WITH POOR VISUAL INFORMATION

Procedure

To v e r i f y t h a t o r t h o g r a p h i c s t r u c t u r e e f f e c t s d o o c c u r w i t h r o t a t e d t e s t s t r i n g s , t h e h igh-accuracy r e a c t i o n t i m e exper iment o f S t u d i e s 1 and 3 was r e p l i c a t e d b u t u s i n g r o t a t e d r a t h e r t h a n u p r i g h t t e s t s t r i n g s . An u p r i g h t t a r g e t l e t t e r was p r e s e n t e d fo l lowed by a r o t a t e d t e s t s t r i n g which remained i n view u n t i l t h e l a s t of up t o f o u r s u b j e c t s responded. S u b j e c t s performed a s q u i c k l y a s p o s s i b l e w h i l e m a i n t a i n i n g h i g h a c c u r a c y . The d e t a i l s o f t h e method, p r o c e d u r e , and r e s u l t s a r e p r e s e n t e d i n Appendix 4 . 7 .


R e a c t i o n t i m e s g e n e r a l l y i n c r e a s e d from words t o t h e i r r e g u l a r - l o w s t r i n g s . F i g u r e 4.19 shows t h a t o v e r a l l e f f e c t was 3 2 msec, which is h i g h l y s i m i l a r t o t h e e f f e c t s of s t r u c t u r e on normal ly p r e s e n t e d s t r i n g s ( c f . F i g u r e 4 . 9 ) . T h i s r e s u l t shows t h a t s t r u c t u r e e f f e c t s d o occur w i t h r o t a t e d s t i m u l i b u t t h a t t h e y a r e n o t l a r g e r t h a n t h e s t r u c t u r e e f f e c t s observed w i t h u p r i g h t s t i m u l i . The i d e a t h a t a t r a d e - o f f e x i s t s between s t i m u l u s q u a l i t y and o r t h o g r a p h i c s t r u c t u r e is n o t s u p p o r t e d by t h e s e r e s u l t s . I t a p p e a r s t h a t bo th a c c u r a c y t a s k s and h igh-accuracy RT t a s k s c a n r e v e a l o r t h o g r a p h i c s t r u c t u r e e f f e c t s b u t t h a t t h e speeded RT t a s k d o e s n o t .

80 CHAPTER 4

SUMMARY OF ACCURACY AND REACTION TIME EXPERIMENTS

These e x p e r i m e n t s t e n d t o s u p p o r t t h e i d e a t h a t p e r c e p t u a l r e s o l u t i o n of a l e t t e r s t r i n g i s f a c i l i t a t e d t o t h e d e g r e e t h e l e t t e r s i n t h e s t r i n g a r e w e l l - s t r u c t u r e d . Both a c c u r a c y t a sks w i t h l i m i t e d s t i m u l u s i n f o r m a t i o n and h i g h a c c u r a c y RT t a s k s w i t h comple te s t i m u l u s i n f o r m a t i o n appear t o be s e n s i t i v e t o t h e e f f e c t s o f o r t h o g r a p h i c s t r u c t u r e . However, t h e magni tude of t h e RT e f f e c t a p p e a r s s m a l l e r because of t h e r e l a t i v e l y l a r g e o v e r a l l RT due t o t h e p r o c e s s i n g time r e q u i r e d f o r o t h e r t h a n v i s u a l p r o c e s s i n g s t a g e s i n t h e RT t a s k . I n c o n t r a s t , a v e r a g e per formance i n t h e a c c u r a c y task i s t i t r a t e d t o remain a t 75% c o r r e c t and t h i s p e r c e n t a g e measure is i n f l u e n c e d a l m o s t c o m p l e t e l y by t h e v i s u a l p r o c e s s i n g s t a g e s . The p o s t hoc e v a l u a t i o n of v a r i o u s measures of o r t h o g r a p h i c s t r u c t u r e i n

H E-I F i g u r e 4.19 R e a c t i o n time and p e r c e n t a g e c o r r e c t a s a f u n c t i o n

of d i s p l a y t y p e i n S tudy 7 : High-accuracy RT Task w i t h Poor V i s u a l I n f o r m a t i o n .


Chapter 5 w i l l a l l o w a more d i r e c t a s s e s s m e n t o f t h e s e n s i t i v i t y of per formance i n t h e RT and a c c u r a c y t a s k s .

A second i m p o r t a n t c o n t r i b u t i o n t o per formance is t h e f e a t u r a l i n f o r m a t i o n c o n t a i n e d i n t h e v i s u a l d i s p l a y . Performance i n b o t h t h e a c c u r a c y and RT t a s k is s e n s i t i v e t o t h e v i s u a l s i m i l a r i t y o f t h e t e s t l e t t e r s t o t h e t a r g e t l e t t e r . Performance on c a t c h t r i a l s is d i s r u p t e d t o t h e e x t e n t t h a t t h e t e s t d i s p l a y c o n t a i n s n o n t a r g e t l e t t e r s t h a t a re s i m i l a r t o t h e t a r g e t l e t t e r . Performance on t a r g e t t r i a l s is n o t s i g n i f i c a n t l y a f f e c t e d s i n c e p r o c e s s i n g i s p r i m a r i l y a f u n c t i o n of t a r g e t l e t t e r p r o c e s s i n g time. However, t h e r e was some h i n t t h a t s i m i l a r n o n t a r g e t s may be i n c o r r e c t l y confused f o r t h e t a r g e t on t a r g e t t r i a l s and, t h e r e f o r e , lead t o a c o r r e c t r e s p o n s e even though t h e t a r g e t i t s e l f was n o t r e c o g n i z e d on t h a t t r i a l .

I n c o n c l u s i o n , b o t h t h e a c c u r a c y and h i g h a c c u r a c y RT t a sks appear t o o f f e r good measures o f t h e u t i l i z a t i o n of o r t h o g r a p h i c s t r u c t u r e i n v i s u a l p r o c e s s i n g . The speeded RT t a s k d o e s n o t r e v e a l e f f e c t s of o r t h o g r a p h i c s t r u c t u r e . B e f o r e e v a l u a t i n g s p e c i f i c d e s c r i p t i o n s o f o r t h o g r a p h i c s t r u c t u r e , some r a t i n g e x p e r i m e n t s were c a r r i e d o u t t o a s s e s s t o what e x t e n t knowledge of o r t h o g r a p h i c s t r u c t u r e is c o n s c i o u s l y a v a i l a b l e and c a n be r e p o r t e d .

OVERT JUDGMENTS

Whereas t h e a c c u r a c y and RT e x p e r i m e n t s imply t h a t v i s u a l r e c o g n i t i o n is s e n s i t i v e t o t h e p r e s e n c e of o r t h o g r a p h i c s t r u c t u r e , i t is a l s o of i n t e r e s t t o d e t e r m i n e t o what e x t e n t s u b j e c t s a r e aware of t h i s knowledge. For t h i s p u r p o s e , s e v e r a l o v e r t judgment e x p e r i m e n t s were conducted . The same 200 s t i m u l u s items i n Appendix 4 . 1 B were p r e s e n t e d t o n a t i v e E n g l i s h s p e a k i n g c o l l e g e s t u d e n t s and judgments i n t h e form of r a t i n g s and p a i r e d judgments were o b t a i n e d . Answers t o t h e f o l l o w i n g q u e s t i o n s were s o u g h t . Could t h e r a t e r s r e l i a b l y a s s i g n r a t i n g s of o r t h o g r a p h i c s t r u c t u r e t o t h e i t e m s ? Would t h e d imens ions u t i l i z e d by t h e r a t e r s d i s c r i m i n a t e t h e items a long our r e g u l a r i t y d imens ion , by p o s i t i o n a l f r e q u e n c y , or both? Would t h e r a t i n g s a s s i g n e d t o t h e items show any meaningfu l r e l a t i o n s h i p t o t h e i r p e r c e p t u a l a c c u r a c y and r e a c t i o n time r e s u l t s found i n t h e p r e v i o u s e x p e r i m e n t s ?

8 2 CHAPTER 4

STUDY 8: TYPICALITY RATINGS

Three sets of r a t i n g s were o b t a i n e d . I n t h e f i r s t one o n l y t h e 160 meaningless anagrams were r a t e d . I n t h e s e c o n d , t h e words were t r a n s f o r m e d i n t o t h e most r e g u l a r pseudowords p o s s i b l e by t h e s u b s t i t u t i o n of a s i n g l e l e t t e r and t h e s e pseudowords were r a t e d a l o n g w i t h t h e anagrams. I n t h e t h i r d , t h e words themselves were i n c l u d e d a l o n g w i t h t h e anagrams. These t h r e e p r o c e d u r e s were used t o o b t a i n t h e most r e l i a b l e r a t i n g s p o s s i b l e and t o d e t e r m i n e how a l t e r a t i o n s i n t h e t o t a l set of items r a t e d a f f e c t e d t h e r a t i n g s o f t h e anagrams. A l l t h r e e r a t i n g s were o b t a i n e d under n e a r l y i d e n t i c a l i n s t r u c t i o n s which asked t h e r a t e r s t o b a s e t h e i r judgments on t h e s i m i l a r i t y o f t h e items t o E n g l i s h words where s i m i l a r i t y was d e f i n e d a s t y p i c a l i t y of E n g l i s h s p e l l i n g . Beyond t h e s e g e n e r a l i n s t r u c t i o n s , no s p e c i f i c a t t e m p t s were made t o i l l u s t r a t e e i t h e r s p e c i f i c r e g u l a r i t y r u l e s o r p o s i t i o n a l - f r e q u e n c y c o n s t r a i n t s .

S u b j e c t s were asked t o r a t e how much t h e l e t t e r s t r i n g s look l i k e E n g l i s h words. The r a t i n g scale went from "most l i k e Engl i sh" t o " l e a s t l i k e E n g l i s h " on a s c a l e from 10 t o 1. C o l l e g e s t u d e n t s r a t e d t h e items i n one o f t h r e e c o n d i t i o n s . Seventy s u b j e c t s r a t e d o n l y t h e 160 anagrams. S i x t y - f i v e s u b j e c t s r a t e d t h e 160 anagrams p l u s 40 pseudowords which were d e r i v e d by m i s s p e l l i n g one l e t t e r i n each of t h e 40 word s t i m u l i . S i x t y - t h r e e s u b j e c t s r a t e d t h e 160 anagrams and t h e 40 words. S u b j e c t s were urged n o t t o a d o p t s t r a t e g i e s of t r y i n g t o see t h e items a s s i m i l a r t o s p e c i f i c words. Those s u b j e c t s t h a t r e c e i v e d a c t u a l words were t o l d t o d i s r e g a r d t h e s e m a n t i c c o n t e n t of t h e words and s i m p l y judge them on t h e b a s i s of t h e i r s i m i l a r i t y t o E n g l i s h s p e l l i n g . The method, p r o c e d u r e , and d e t a i l e d r e su l t s a r e p r e s e n t e d i n Appendix 4.8.

F i g u r e 4.20 shows t h e a v e r a g e r a t i n g s f o r t h e items f o r each of t h e t h r e e g r o u p s of s u b j e c t s . The r a t i n g s a s s i g n e d t o t h e 160 anagrams were v e r y s t a b l e a c r o s s t h e t h r e e r a t i n g c o n t e x t s . The s i x c o r r e l a t i o n s between a l l p o s s i b l e p a i r s of r a t i n g s a c r o s s t h e t h r e e c o n t e x t s were a l l .97. T h i s r e s u l t d e m o n s t r a t e s t h a t t h e r a t i n g s of t h e anagrams were n o t i n f l u e n c e d by t h e p r e s e n c e of a c t u a l words i n t h e sample of items t o be r a t e d . The f i g u r e a l s o shows t h a t t h e r a t i n g s were p r i m a r i l y de te rmined by t h e r e g u l a r i t y of t h e items r a t h e r t h a n by p o s i t i o n a l f r e q u e n c y . Although t h e e f f e c t of p o s i t i o n a l f requency was s t a t i s t i c a l l y s i g n i f i c a n t , t h e r e s u l t s show t h a t


r e g u l a r i t y produced a b o u t s e v e n times t h e e f f e c t t h a t p o s i t i o n a l f r e q u e n c y d i d .

The r e s u l t s i n d i c a t e t h a t when s u b j e c t s a r e asked t o r a t e items on t h e b a s i s of t h e s i m i l a r i t y t o E n g l i s h s p e l l i n g , t h e y t e n d t o e v a l u a t e t h e items i n terms o f n o t i o n s of r e g u l a r i t y r a t h e r t h a n i n t e r m s o f t h e p o s i t i o n a l f r e q u e n c y of t h e items. As c a n be s e e n i n t h e f i g u r e , t h e words were r a t e d a s more t y p i c a l t h a n even t h e r e g u l a r - h i g h anagrams. Even t h e pseudowords c r e a t e d by m i s s p e l l i n g t h e words by a s i n g l e l e t t e r produced h i g h e r r a t i n g s t h a n t h e r e g u l a r anagrams. T h i s r e s u l t means t h a t t h e word s t i m u l i and t h e i r m i s s p e l l i n g s were e i t h e r more t y p i c a l a c c o r d i n g t o t h e s u b j e c t ' s n o t i o n of E n g l i s h s p e l l i n g or t h a t t h e l e x i c a l c o n t e n t o f t h e words and p o s s i b l y t h e i r m i s s p e l l i n g s c o u l d n o t be ignored i n making t h e judgment .

If t h e r a t i n g s and t h e t a r g e t s e a r c h e x p e r i m e n t s are measur ing t h e same knowledge of o r t h o g r a p h i c s t r u c t u r e , t h e n a

WORD R-H R-L I-H I-L

F i g u r e 4 . 2 0 R a t i n g s from 10 (most l i k e E n g l i s h ) t o 1 ( l e a s t l i k e E n g l i s h ) as a f u n c t i o n of d i s p l a y t y p e i n S tudy 8 : T y p i c a l i t y R a t i n g s .

8 4 CHAPTER 4

c l o s e r e l a t i o n s h i p between t h e r a t i n g s and t h e RT and a c c u r a c y measures of t h e p r e v i o u s e x p e r i m e n t s s h o u l d be observed . Accord ingly , we examined t h e r e l a t i o n s h i p between t h e s e r a t i n g s and t h e p e r c e p t u a l per formance d a t a c o l l e c t e d i n S t u d i e s 1, 2 , and 3. Average RTs were o b t a i n e d f o r e a c h o f t h e 280 s t i m u l u s i t e m s by a v e r a g i n g t h e c o r r e c t r e s p o n s e RTs f o r t a r g e t and c a t c h t r i a l s from t h e r e a c t i o n time e x p e r i m e n t of Study 1 and t h e mixed-case exper iment o f S tudy 3. T h i s provided a n a v e r a g e RT f o r e a c h i tem based on a p p r o x i m a t e l y 204 o b s e r v a t i o n s . S i m i l a r l y , a n a v e r a g e a c c u r a c y was found f o r each item based on t h e t a r g e t and c a t c h t r i a l s f o r t h e s u b j e c t s i n t h e a c c u r a c y e x p e r i m e n t of S tudy 1 and t h e p r e c u e v e r s u s p o s t c u e exper iment of S tudy 2. The a v e r a g e a c c u r a c y o f e a c h item was based on 150 o b s e r v a t i o n s .

C o r r e l a t i o n s between t h e t h r e e r a t i n g s , a v e r a g e RT, and a v e r a g e a c c u r a c y a r e shown i n Table 4 . 4 . Two t h i n g s may be observed i n Table 4 . 4 . F i r s t , t h e c o r r e l a t i o n between t h e a c c u r a c i e s and RTs of a l l items was .56. T h e r e f o r e , d e s p i t e t h e magnitude of t h e observed d i f f e r e n c e s between RT and a c c u r a c y measures, b o t h e x p e r i m e n t a l p r o c e d u r e s appear t o r e v e a l a common p r o c e s s i n g component. T h i s w i l l become even more e v i d e n t i n t h e - c o r r e l a t i o n a l a n a l y s e s ( t o be d i s c u s s e d i n Chapter 5) which d e m o n s t r a t e t h a t b o t h item a c c u r a c y and RT tend t o show s i m i l a r c o r r e l a t i o n s w i t h v a r i o u s measures o f o r t h o g r a p h i c s t r u c t u r e .

The c o r r e l a t i o n s between item a c c u r a c y , RT, and t h e r a t i n g s a r e i l l u m i n a t i n g . C o r r e l a t i o n s between t h e two p e r c e p t u a l measures and t h e r a t i n g s a r e q u i t e h i g h . The p e r c e p t u a l measures and t h e r a t i n g s s h a r e 31% t o 53% common v a r i a n c e . Whereas t h e knowledge s t r u c t u r e s tapped by t h e r a t i n g p r o c e d u r e s need n o t n e c e s s a r i l y r e l a t e t o t h e knowledge s t r u c t u r e i n f e r r e d from t h e p e r c e p t u a l t a s k s , i t is e n c o u r a g i n g t o o b s e r v e t h a t t h e r e d o e s appear t o be a l a w f u l cor respondence . I t would appear t h a t what one knows a b o u t o r t h o g r a p h i c s t r u c t u r e n o t o n l y i n f l u e n c e s p e r c e p t i o n b u t a l s o i s amenable t o i n t e r r o g a t i o n by c o n s c i o u s p r o c e s s e s . A second encouraging a s p e c t of t h i s o b s e r v a t i o n is t h a t r a t i n g t a s k s and p e r c e p t u a l t a s k s may be regarded as converg ing measures o f o r t h o g r a p h i c s t r u c t u r e . I f bo th t a p a common d a t a base of o r t h o g r a p h i c s t r u c t u r e knowledge, t h e n w e can r e f i n e our unders tanding of t h i s knowledge s o u r c e by means of r a t i n g t a s k s as well a s p e r c e p t u a l t a sks . For t h e c o r r e l a t i o n a l a n a l y s e s i n Chapter 5 , i t e m a c c u r a c i e s , R T s , and r a t i n g s a r e e a c h r e g a r d e d


Table 4 . 4 C o r r e l a t i o n s among a v e r a g e a c c u r a c y , a v e r a g e RT, and t h e t h r e e r e g u l a r i t y r a t i n g s f o r t h e 200 s t i m u l u s i tems .

(1) ( 2 ) ( 3 ) ( 4 ) ( 5 )

(1) Average a c c u r a c y --

( 2 ) Average RT -.56 --

( 3 ) R a t i n g w i t h o u t words .58* -.56* --

( 4 ) R a t i n g w i t h pseudowords .72 -.61 .97 --

( 5 ) R a t i n g w i t h words .73 -.60 .97 .97 --

* C o r r e l a t i o n based on t h e 160 anagrams o n l y , a l l o t h e r c o r r e l a t i o n s based on a l l 200 s t i m u l u s items.

as r e l a t e d c o l l a t e r a l dependent measures p o t e n t i a l l y r e v e a l i n g a common o r t h o g r a p h i c s t r u c t u r e component.

STUDY 9: POSITIONAL-FREQUENCY RATINGS

The r a t i n g s o f S tudy 8 i n d i c a t e t h a t s u b j e c t s , when g i v e n r e l a t i v e l y n e u t r a l i n s t r u c t i o n s , b a s e t h e i r r a t i n g s more on r e g u l a r i t y t h a n on p o s i t i o n a l f r e q u e n c y . B e f o r e we can c o n c l u d e t h a t t h e r e a d e r ' s c o n s c i o u s knowledge is b e s t r e p r e s e n t e d by r e g u l a r i t y , i t is n e c e s s a r y t o d e t e r m i n e whether s u b j e c t s c a n be i n s t r u c t e d t o respond on t h e b a s i s of p o s i t i o n a l - f r e q u e n c y i n f o r m a t i o n . A c c o r d i n g l y , t h e r a t i n g exper iment w i t h o n l y 160 anagrams was r e p l i c a t e d b u t now t h e s u b j e c t s were g i v e n s p e c i f i c p o s i t i o n a l - f r e q u e n c y i n s t r u c t i o n s . The i n s t r u c t i o n s e x p l a i n e d t h e c o n c e p t of p o s i t i o n a l f r e q u e n c y a l o n g w i t h r e l e v a n t examples and t o l d t h e s u b j e c t s t o r a t e t h e i t e m s e x p l i c i t l y on t h i s b a s i s . The e x a c t i n s t r u c t i o n s ,

86 CHAPTER 4

9 -

8 -

7 -

6 -

6 5 -

a 4 -

3 -

2 -

method, and p r o c e d u r e a r e g i v e n i n t h e Appendix 4 . 9 . Except f o r t h e i n s t r u c t i o n s , t h e p r o c e d u r e r e p l i c a t e d t h e p r e v i o u s r a t i n g exper iment t h a t gave i n s t r u c t i o n s w i t h r e s p e c t t o t y p i c a l i t y o f E n g l i s h s p e l l i n g . The r e s u l t s and d e t a i l e d a n a l y s e s a r e g i v e n i n Appendix 4 . 9 .

F i g u r e 4 . 2 1 g i v e s t h e r e s u l t s o f t h i s e x p e r i m e n t s t r e s s i n g p o s i t i o n a l f r e q u e n c i e s a l o n g w i t h t h e r e s u l t s of t h e p r e v i o u s exper iment s t r e s s i n g t y p i c a l i t y . The r e s u l t s show t h a t t h e r a t i n g r e s p o n s e s were v e r y s i m i l a r w i t h both s e t s o f i n s t r u c t i o n s . However, p o s i t i o n a l f r e q u e n c y d i d m a k e more of a c o n t r i b u t i o n w i t h p o s i t i o n a l - f r e q u e n c y i n s t r u c t i o n s t h a n w i t h t y p i c a l i t y i n s t r u c t i o n s . O v e r a l l , s u b j e c t s tended t o r a t e h i g h p o s i t i o n a l - f r e q u e n c y items a s s l i g h t l y h i g h e r t h a n low p o s i t i o n a l - f r e q u e n c y items t o a g r e a t e r d e g r e e w i t h p o s i t i o n a l - f r e q u e n c y i n s t r u c t i o n s t h a n w i t h t y p i c a l i t y i n s t r u c t i o n s . Also , t h e e f f e c t of r e g u l a r i t y on t h e judgments

1-

I I 1 I I

TLPblfiY , .. " ... D-.-..O Poeltlonal Frequency

F i g u r e 4 . 2 1 R a t i n g s from 1 0 (most l i k e E n g l i s h ) t o 1 ( l e a s t l i k e E n g l i s h ) as a f u n c t i o n of d i s p l a y t y p e f o r t y p i c a l i t y i n s t r u c t i o n s (S tudy 8 ) and p o s i t i o n a l - f r e q u e n c y i n s t r u c t i o n s (S tudy 9 ) .


was s l i g h t l y a t t e n t u a t e d w i t h p o s i t i o n a l - f r e q u e n c y i n s t r u c t i o n s r e l a t i v e t o t y p i c a l i t y i n s t r u c t i o n s .

The r a t i n g e x p e r i m e n t s i n d i c a t e t h a t o r t h o g r a p h i c s t r u c t u r e i n terms of r e g u l a r i t y a p p e a r s t o be more c o n s c i o u s l y a v a i l a b l e t h a n s t r u c t u r e i n t e r m s of p o s i t i o n a l f r e q u e n c y . S u b j e c t s t e n d t o r a t e r e g u l a r items a s most l i k e E n g l i s h and i r r e g u l a r items as l e a s t l i k e E n g l i s h r e g a r d l e s s of whether t h e y were g i v e n t y p i c a l i t y i n s t r u c t i o n s O K p o s i t i o n a l - f r e q u e n c y i n s t r u c t i o n s . One l i m i t a t i o n i n t h e r a t i n g e x p e r i m e n t s may b e t h a t s u b j e c t s tend t o r a t e t h e items on t h e b a s i s of r e g u l a r i t y r e g a r d l e s s of t h e i n s t r u c t i o n s t h a t a r e g i v e n . T h e r e f o r e , a more d i r e c t index of t h e p s y c h o l o g i c a l r e a l i t y o f t h e s e two c o n c e p t s a s d e s c r i p t i o n s of o r t h o g r a p h i c S t r u c t u r e s h o u l d be o b t a i n e d .

STUDY l a : REGULARITY VERSUS POSITIONAL-FREQUENCY JUDGMENTS

I n o r d e r t o o b t a i n a more d i r e c t index of o r t h o g r a p h i c S t r u c t u r e , p r e c i s e r e g u l a r i t y i n s t r u c t i o n s were c o n t r a s t e d w i t h p r e c i s e p o s i t i o n a l - f r e q u e n c y i n s t r u c t i o n s . I t e m s from e a c h of t h e f o u r t y p e s of 160 anagrams were p a i r e d w i t h each o t h e r such t h a t items of one t y p e were p a i r e d w i t h items of t h e same t y p e o r w i t h items of t h e o t h e r t y p e s . Some s u b j e c t s were g i v e n p a i r s of items and asked t o p i c k t h e i t e m from each p a i r t h a t was most r e g u l a r . Other s u b j e c t s were g i v e n t h e same p a i r s and asked t o p i c k t h e i tem t h a t was h i g h e s t i n t e r m s of p o s i t i o n a l f r e q u e n c y . The i n s t r u c t i o n s , method, pKOCedUKe, and r e s u l t s a r e g i v e n i n Appendix 4.10. T h i s exper iment a l lowed a d i r e c t a s s e s s m e n t of t h e r e l a t i v e weight c a r r i e d by o r t h o g r a p h i c r e g u l a r i t y and p o s i t i o n a l f r e q u e n c y i n t h e r e a d e r ' s e v a l u a t i o n of o r t h o g r a p h i c s t r u c t u r e . The judgments of t h e s e two g r o u p s of s u b j e c t s were t a b u l a t e d a s t h e p r o p o r t i o n of times t h e y c h o s e an item from one c a t e g o r y when it was p a i r e d w i t h a n item from a n o t h e r c a t e g o r y . These r e s u l t s a r e p r e s e n t e d a s T a b l e 4 . 5 where t h e c e l l s of t h e t a b l e g i v e t h e p r o p o r t i o n of times an i t e m from t h e column c a t e g o r y was s e l e c t e d when p a i r e d w i t h an item from t h e T O W c a t e g o r y .

Before d i s c u s s i n g t h e a c t u a l r e s u l t s i n Table 4 .5 , i t is i n s t r u c t i v e t o h y p o t h e s i z e how t h i s t a b l e s h o u l d have t u r n e d o u t i f t h e s u b j e c t s i n t h e two c o n d i t i o n s had a comple te knowledge o f r e g u l a r i t y and p o s i t i o n a l f r e q u e n c y and had a p p l i e d t h i s knowledge i n accordance w i t h t h e i n s t r u c t i o n s . Whenever t h e two items d i f f e r e d on t h e d imens ion r e l e v a n t f o r

88 CHAPTER 4

Table 4.5 Paired-judgment preferences for the 200 stimuli under regularity and positional-frequency instructions. Cells represent proportion of times the column item was chosen over the row item. The numbers in parentheses give the hypothetical outcomes assuming that the subject had knowledge of both dimensions and followed instructions.

Regularity Instructions

R- H R- L I-H I-L

R- H .475 (.5)

R- L ,693 .445 (.5) C.5)

I-H .910 .a77 .523 (1.0) (1.0) (.5)

I-L .938 .908 .509 .518 11.0) (1.0) (.5) ( . 5 )

Positional Frequency Instructions

R- H R- L I-H I-L

R- H .527 (.5)

R- L .704 .488 (1.0) (.5)

I - H .866 .740 .525 (-5) (.0) (.5)

I-L .953 .a95 .687 .494 (1.0) (.5) (1.0) (.5)


Table 4.6 Chi -square f o r t h e two p r e d i c t e d outcomes a g a i n s t t h e observed outcomes f o r t h e two i n s t r u c t i o n c o n d i t i o n s i n s t u d y 10 .

P r e d i c t e d Outcome

P o s i t i o n a l I n s t r u c t i o n s R e g u l a r i t y Frequency

R e g u l a r i t y 93.63 1561.26

P o s i t i o n a l Frequency 258.90 1367.50

t h e judgment , t h e s u b j e c t s s h o u l d have a lways chosen t h e " c o r r e c t item," on t h a t d i m e n s i o n , i . e . , t h e one t h a t was more r e g u l a r or t h e one t h a t was h i g h e r i n p o s i t i o n a l f requency . Whenever t h e two items were a t e q u i v a l e n t l e v e l s on t h e r e l e v a n t d imens ion , t h e s u b j e c t s s h o u l d have chosen i n d i f f e r e n t l y between them. These " p e r f e c t " h y p o t h e t i c a l outcomes a r e a l s o shown i n Table 4.5.

Comparing t h e two p a n e l s o f Table 4.5 we o b s e r v e t h a t f o r bo th sets of i n s t r u c t i o n s , s u b j e c t s made c h o i c e s more c o n s i s t e n t w i t h t h e a p p l i c a t i o n of r e g u l a r i t y t h a n w i t h t h e a p p l i c a t i o n of p o s i t i o n a l f r e q u e n c y . I n o r d e r t o assess how w e l l t h e r e su l t s conformed t o what would be e x p e c t e d from p e r f e c t knowledge and u t i l i z a t i o n of r e g u l a r i t y o r p o s i t i o n a l f r e q u e n c y , t h e two p r e d i c t e d outcomes were compared w i t h t h e ac tua l outcomes under b o t h i n s t r u c t i o n c o n d i t i o n s . Table 4.6 g i v e s t h e Chi -square v a l u e s f o r compar isons of t h e two p r e d i c t e d outcomes a g a i n s t t h e observed outcomes f o r b o t h i n s t r u c t i o n c o n d i t i o n s . The value 's s u p p o r t t h e i n t e r p r e t a t i o n t h a t t h e s u b j e c t s ' performance is more a d e q u a t e l y d e s c r i b e d by r e g u l a r i t y t h a n p o s i t i o n a l f requency . However, though s u b j e c t s appear t o be u s i n g m o s t l y r e g u l a r i t y a s a b a s i s of t h e i r r a t i n g s , i n n e i t h e r c a s e d i d t h e r a t i n g s i n d i c a t e t h a t o n l y r e g u l a r i t y was u s e d . I f we compare t h e two p a n e l s of Table 4.5 t o each o t h e r , we s e e t h a t t h e r e was a n a d d i t i o n a l c o n t r i b u t i o n of p o s i t i o n a l f r e q u e n c y when s u b j e c t s were e x p l i c i t l y i n s t r u c t e d t o b a s e t h e i r judgments on f r e q u e n c y . E v i d e n t l y , s u b j e c t s c a n modify t h e i r judgments s l i g h t l y when g i v e n e x p l i c i t i n s t r u c t i o n s t o a t t e n d t o p o s i t i o n a l f r e q u e n c y .

CHAPTER 4

SUMMARY OF OVERT JUDGMENT EXPERIMENTS

The e x p e r i m e n t s s u p p o r t t h e i d e a t h a t knowledge of o r t h o g r a p h i c s t r u c t u r e is c o n s c i o u s l y a v a i l a b l e and c a p a b l e of r e p o r t . S u b j e c t s a re r e l a t i v e l y good a t a s s i g n i n g r a t i n g s on t h e b a s i s of ru le -governed r e g u l a r i t y b u t r e l a t i v e l y poor a t r a t i n g items on t h e b a s i s of s t a t i s t i c a l redundancy. S i m i l a r l y , choos ing which of a p a i r of items i s more r e g u l a r is r e l a t i v e l y e a s y whereas c h o o s i n g which is more f r e q u e n t is n e a r l y i m p o s s i b l e . The p o s t hoc c o r r e l a t i o n s i n Chapter 5 w i l l a l l o w a more d i r e c t and b r o a d e r a s s e s s m e n t of t h e n a t u r e of t h e knowledge u t i l i z e d i n o v e r t judgments of l e t t e r s t r i n g s .

APPENDIX 4 . 1 9 1

Appendix 4 . 1

D e t a i l s o f Method, P r o c e d u r e , and R e s u l t s o f S tudy 1: I n i t i a l R e p l i c a t i o n

Method

S u b j e c t s . One g r o u p of 1 4 I n t r o d u c t o r y Psychology s t u d e n t s p a r t i c i p a t e d i n t h e p o s t c u e a c c u r a c y t a s k f o r an t,t,>-, a day on each o f 2 c o n s e c u t i v e d a y s . The d a t a from t h r c a d d i t i o n a l sub jec t s were l o s t due t o computer sys tem f , i i l u r . S i x o t h e r s u b j e c t s were t e s t e d b u t t h e i r d a t a were n o t i n c l i r l e d because of i n a d m i s s i b l e o v e r a l l a c c u r a c y . Another g r o u p o f 14 IntKOdUCtOKy Psychology s t u d e n t s p a r t i c i p a t e d f o r a n hour e a c h day on 2 c o n s e c u t i v e d a y s i n t h e p r e c u e RT t a s k . A l l s u b j e c t s i n b o t h t a s k s passed a p r e l i m i n a r y v i s i o n t e s t e s t a b l i s h i n g a t l e a s t 20/40 a c u i t y f o r bo th e y e s . A l l s u b j e c t s were awarded r e s e a r c h p a r t i c i p a t i o n c r e d i t toward t h e i r psychology g r a d e .

S t i m u l i . A l i s t i n g of t h e 100 h i g h e s t and 108 l o w e s t summed s i n g l e - l e t t e r p o s i t i o n a l - f r e q u e n c y anagrams were o b t a i n e d f o r s e v e r a l hundred common s i x - l e t t e r words selected from t h e Kucera and F r a n c i s (1967) word l i s t . The l i s t i n g s o f t h e anagrams were produced by a computer program which g e n e r a t e d a l l 720 p o s s i b l e p e r m u t a t i o n s f o r each s i x - l e t t e r word. The p o s i t i o n a l f r e q u e n c y f o r each p e r m u t a t i o n was computed from t h e Mayzner and T r e s s e l t (1965) s i n g l e - l e t t e r c o u n t s f o r s i x - l e t t e r words by summing t h e p o s i t i o n - d e p e n d e n t f r e q u e n c y for e a c h l e t t e r . Words w i t h r e p e a t e d l e t t e r s were n o t used. From t h e 720 anagrams f o r e a c h s i x - l e t t e r word, two were chosen w i t h h i g h - p o s i t i o n a l f r e q u e n c i e s and two were chosen w i t h l o w - p o s i t i o n a l f r e q u e n c i e s . Wi th in e a c h f r e q u e n c y p a i r , one member was o r t h o g r a p h i c a l l y r e g u l a r ahd t h e o t h e r o r t h o g r a p h i c a l l y i r r e g u l a r . The r u l e s used f o r j u d g i n g r e g u l a r i t y a r e l i s t e d i n Appendix 4 . 1 A . L i s t e d i n Appendix 4 . 1 8 a r e t h e 200 s t i m u l u s i t ems-- the 40 words and t h e 4 anagrams of each word. One-hundred twenty p r a c t i c e s t i m u l i were g e n e r a t e d from 2 4 a d d i t i o n a l words. These i t e m s were n o t a s e v e n l y matched f o r r e g u l a r i t y and p o s i t i o n a l f r e q u e n c y a s t h e e x p e r i m e n t a l i t e m s and a few c o n t a i n e d r e p e a t e d l e t t e r s .

Two o c c u r r e n c e s of each o f t h e 120 p r a c t i c e s t i m u l i were randomized f o r e a c h s u b j e c t ' s p r a c t i c e sequence and two o c c u r r e n c e s of e a c h of t h e 200 e x p e r i m e n t a l s t i m u l i were randomized f o r e a c h s u b j e c t ' s e x p e r i m e n t a l sequence . One o c c u r r e n c e was t e s t e d a s a t a r g e t t r i a l and one a s a c a t c h

92 CHAPTER 4

t r i a l . On t a r g e t t r i a l s . t h e l e t t e r was s e l e c t e d randomly w i t h rep lacement from t h e s i x l e t t e r s i n t h e t e s t s t r i n g . For c a t c h t r i a l s , a t a r g e t was s e l e c t e d randomly from t h e s e t of 26 l e t t e r s weighted by t h e i r p r o b a b i l i t y o f o c c u r r e n c e i n t h e s t i m u l u s s e t . If t h e s e l e c t e d l e t t e r was p r e s e n t i n t h e d i s p l a y s t r i n g , a d d i t i o n a l drawings w i t h rep lacement were made u n t i l a n a p p r o p r i a t e t a r g e t l e t t e r was s e l e c t e d . The l e t t e r s 1, k, 9, 5 , and 2 d i d n o t o c c u r i n t h e e x p e r i m e n t a l s t i m u l u s s t r i n g s and t h e r e f o r e were never t e s t e d .

The d i s p l a y s were p r e s e n t e d on a Beehive model v i d e o computer t e r m i n a l under t h e c o n t r o l o f a H a r r i s DC6024/5 computer . Hardware m o d i f i c a t i o n s p e r m i t t e d t h e t e r m i n a l ' s v i d e o t o be t u r n e d on and o f f wi th program-generated c o n t r o l s i g n a l s . The d i s p l a y s t r i n g s were loaded i n t o t h e memory b u f f e r of t h e t e r m i n a l w i t h t h e v i d e o o f f and t h e n t h e v i d e o was t u r n e d on f o r t h e a p p r o p r i a t e e x p o s u r e d u r a t i o n . The Beehive employs a P4, b lue-whi te phosphor which d e c a y s t o . l% of maximum luminance w i t h i n 32 msec. The exper iment was conducted i n a p a r t i a l l y darkened room t o enhance image c o n t r a s t .

A l l s i n g l e - l e t t e r t a r g e t and l e t t e r - s t r i n g t e s t d i s p l a y s were p r e s e n t e d i n l o w e r c a s e l e t t e r s . The Beehive u s e s a 5 x 7 d o t m a t r i x , 2.5 mm wide x 5 mm h i g h , A t t h e a v e r a g e s u b j e c t ' s viewing d i s t a n c e of a p p r o x i m a t e l y 38 cm, t h e s i x - l e t t e r s t r i n g s subtended a h o r i z o n t a l v i s u a l a n g l e of 2.25 d e g r e e s and a v e r t i c a l v i s u a l a n g l e of .75 d e g r e e . The d i s p l a y s were p r e s e n t e d i n t h e upper c e n t e r of t h e s c r e e n . The s i n g l e - l e t t e r t a r g e t was p o s i t i o n e d t o a p p e a r t h r e e c h a r a c t e r p o s i t i o n s t o t h e l e f t of t h e s t r i n g d i s p l a y , a h o r i z o n t a l v i s u a l a n g l e s e p a r a t i o n of .75 d e g r e e . To a c h i e v e a r a p i d and c o n t r o l l e d p r e s e n t a t i o n r a t e , t h e e n t i r e d i s p l a y sequence f o r a n item was d i s p l a y e d b e n e a t h a c a r d b o a r d mask a f f i x e d t o t h e f a c e of t h e c a t h o d e r a y t u b e ( C R T ) . A r e c t a n g u l a r window i n t h e mask s e r v e d a s a f i x a t i o n box and p e r m i t t e d o n l y t h e d e s i r e d p o r t i o n of t h e d i s p l a y t o be o b s e r v e d .

-___ Procedure . The s u b j e c t s i n t h e a c c u r a c y t a s k were informed t h a t t h e exposure d u r a t i o n would be b r i e f and would be a d j u s t e d d u r i n g t h e s e s s i o n t o m a i n t a i n a n a c c u r a c y o f 75%. A

t r i a l began w i t h t h e p r e s e n t a t i o n of t h e s i x - l e t t e r s t i m u l u s s t r i n g f o r a b r i e f d u r a t i o n . A f t e r t h e a p p r o p r i a t e e x p o s u r e d u r a t i o n , t h e d i s p l a y was s c r o l l e d upward on t h e CRT r e p l a c i n g t h e s t r i n g w i t h a masking s t i m u l u s c o n s i s t i n g of s i x u p p e r c a s e - Xs. The masking s t i m u l u s was p r e s e n t e d f o r 208 msec t h e n s c r o l l e d a g a i n t o p r e s e n t t h e t a r g e t l e t t e r . The t a r g e t l e t t e r remained i n view u n t i l t h e s u b j e c t responded, a t which t i m e t h e

% p a r a t u s .

APPENDIX 4 . 1 93

d i s p l a y was t e r m i n a t e d and a 500 msec i n t e r t r i a l i n t e r v a l begun.

The e x p o s u r e d u r a t i o n of t h e t e s t s t r i n g was i n d i v i d u a l l y d e t e r m i n e d f o r each s u b j e c t d u r i n g t h e p r a c t i c e t r i a l s . Because of t h e 60 Hz r e f r e s h r a t e o f t h e CRT one r e f r e s h c y c l e (16.7 msec) was chosen a s t h e b a s i c t i m e u n i t . The number of c y c l e s needed t o a c h i e v e a n o v e r a l l a c c u r a c y l e v e l of 75% was d e t e r m i n e d o n - l i n e u s i n g a v e r s i o n of t h e a d a p t i v e PEST a l g o r i t h m ( T a y l o r & Creelman, 1 9 6 7 ) . Exposure d u r a t i o n was n o t changed d u r i n g t h e e x p e r i m e n t a l t r i a l s . The i n i t i a l e x p o s u r e d u r a t i o n was 20 c y c l e s (334 msec) f o r a l l s u b j e c t s . The r a n g e of e x p o s u r e s needed by t h e 1 4 s u b j e c t s f o r 75% a c c u r a c y was 1 t o 1 2 c y c l e s w i t h a median e x p o s u r e d u r a t i o n o f 3 c y c l e s (50 msec).

The s u b j e c t s i n t h e RT t a s k were i n s t r u c t e d t o respond a s r a p i d l y and a s a c c u r a t e l y a s p o s s i b l e . A l l s u b j e c t s were a l s o t o l d t h a t one-ha l f o f t h e t r i a l s would be t a r g e t t r i a l s and one-ha l f would be c a t c h t r i a l s . The d i s p l a y sequence was a l t e r e d t o accommodate t h e p r e c u i n g . A t r i a l began w i t h t h e p r e s e n t a t i o n of t h e t a r g e t l e t t e r a t t h e l e f t of t h e f i x a t i o n window f o r 500 msec. The t a r g e t l e t t e r was t h e n t e r m i n a t e d and 1 sec l a t e r t h e s t i m u l u s s t r i n g was d i s p l a y e d . The s t i m u l u s remained i n view u n t i l t h e s u b j e c t responded, a t which time t h e d i s p l a y was t e r m i n a t e d and a 500 msec i n t e r v a l begun. A masking f i e l d was n o t used .

To a c q u a i n t s u b j e c t s i n b o t h t h e a c c u r a c y and RT t a s k s w i t h t h e r e s p o n s e p r o c e d u r e and v i s u a l d i s p l a y , e a c h d a y ' s s e s s i o n began w i t h 10 t r i a l s c o n s i s t i n g of o n l y t h e word YES o r NO i n s t e a d of t h e d i s p l a y s t r i n g . No t a r g e t l e t t e r was p r e s e n t e d . The s u b j e c t s p r e s s e d t h e c o r r e s p o n d i n g l y l a b e l e d r e s p o n s e b u t t o n s . The YES r e s p o n s e was a s s i g n e d t o e a c h s u b j e c t ' s p r e f e r r e d hand ( r i g h t hand f o r 9 of t h e 1 4 s u b j e c t s i n t h e a c c u r a c y t a s k ; 13 o f t h e 1 4 s u b j e c t s i n t h e RT t a s k ) .

The "yes-no" t r i a l s were fo l lowed by t h e 240 p r a c t i c e t r i a l s and t h e 400 e x p e r i m e n t a l t r i a l s . The p r a c t i c e t r i a l s were d i v i d e d i n t o f o u r 60 t r i a l b l o c k s and t h e e x p e r i m e n t a l t r i a l s were d i v i d e d i n t o f i v e 8 0 - t r i a l b l o c k s . A t t h e end of each b lock t h e s u b j e c t was g i v e n an o p p o r t u n i t y t o r e s t and r e c e i v e d feedback i n t h e form of a p e r c e n t c o r r e c t s c o r e o r RT and e r r o r r a t e , a s a p p r o p r i a t e , for t h e p r e c e d i n g b l o c k . A l l s u b j e c t s were t e s t e d i n two such s e s s i o n s s c h e d u l e d on c o n s e c u t i v e d a y s .

94 CHAPTER 4

Re s u l t s

O r t h o g r a p h i c s t r u c t u r e . Analyses o f v a r i a n c e were c a r r i e d o u t on t h e a v e r a g e p e r c e n t a g e c o r r e c t f o r e a c h s u b j e c t f o r e a c h of t h e 5 d i s p l a y t y p e s and t a r g e t v e r s u s c a t c h t r i a l s . For t h e accuracy t a s k , t h e main e f f e c t of d i s p l a y t y p e was s i g n i f i c a n t , - F ( 4 , 52) = 82.56, E < .001, and t h e d i f f e r e n c e s among t h e s e c o n d i t i o n s were t e s t e d w i t h s p e c i f i c c o n t r a s t s . Accuracy f o r words was 12% g r e a t e r t h a n f o r t h e b e s t pseudoword items ( r e g u l a r - h i g h ) , E (1, 52) = 40.54, E < .001. Three o r t h o g o n a l c o n t r a s t s ana logous t o a 2 x 2 a n a l y s i s o f v a r i a n c e f o r t h e f o u r nonword d i s p l a y t y p e s r e v e a l e d t h a t t h e r e g u l a r s t r i n g s were judged 8% more a c c u r a t e l y t h a n i r r e g u l a r s t r i n g s , E (1, 52) = 7.05, E < .01. High p o s i t i o n a l - f r e q u e n c y s t r i n g s were judged 5% more a c c u r a t e l y t h a n low p o s i t i o n a l - f r e q u e n c y s t r i n g s , E (1, 52) = 7.05, E < .01. The i n t e r a c t i o n of p o s i t i o n a l f r e q u e n c y and r e g u l a r i t y was n o t s i g n i f i c a n t , 2 (1, 52) = 3.20, p > .05.

For t h e RT a n a l y s i s , RTs f o r i n c o r r e c t t r i a l s and c o r r e c t t r i a l RTs which exceeded 2 sec ( l e s s t h a n .2% o f t h e d a t a ) were exc luded from t h e a n a l y s e s l e a v i n g a p p r o x i m a t e l y 76 o f 80 p o s s i b l e o b s e r v a t i o n s p e r c e l l . For t h e RT d a t a , t h e r e was a l s o a s i g n i f i c a n t main e f f e c t of d i s p l a y t y p e , 1 ( 4 , 52) = 17.16, E < .001. T h i s main e f f e c t was examined w i t h t h e same s e t of s p e c i f i c c o n t r a s t s . The 7 msec advantage f o r words o v e r r e g u l a r - h i g h pseudowords was n o t s i g n i f i c a n t , E (1, 52) = 2.01, E > .10. Regular items were judged 23 msec f a s t e r t h a n i r r e g u l a r items, a s i g n i f i c a n t d i f f e r e n c e , E (1, 52) = 9.54, E < .005. N e i t h e r t h e 4 msec d i f f e r e n c e between h i g h and low p o s i t i o n a l f r e q u e n c y nor t h e i n t e r a c t i o n of r e g u l a r i t y and p o s i t i o n a l f r e q u e n c y were s i g n i f i c a n t , b o t h Es < 1. E r r o r p e r c e n t a g e s were a n a l y z e d s i m i l a r l y t o t h e RTs. The main e f f e c t of d i s p l a y t y p e was n o t s i g n i f i c a n t , E ( 4 , 52) = 1.13.

S i m i l a r i t y a n a l y s e s . To t e s t f o r t h e e f f e c t s of s i m i l a r i t y between t h e t a r g e t l e t t e r and t h e l e t t e r s i n t h e d i s p l a y , t h e d a t a were f i r s t pooled a c r o s s d i s p l a y t y p e s . Each t r i a l ' s t a r g e t l e t t e r was c l a s s i f i e d a c c o r d i n g t o which l e t t e r s i n t h e d i s p l a y were l i k e l y t o be s e e n as v e r y s i m i l a r t o t h e t a r g e t . The c l a s s i f i c a t i o n was d e r i v e d from t h e l o w e r c a s e s i n g l e - l e t t e r c o n f u s a b i l i t y s t u d y p u b l i s h e d by Bouma ( 1 9 7 1 ) . A l e t t e r was counted a s s i m i l a r t o t h e t a r g e t l e t t e r i f t h e l e t t e r was e r r o n e o u s l y i d e n t i f i e d a s t h e t a r g e t more t h a n 5% o f t h e time. Table 4 . 2 p r e s e n t s t h e c l a s s i f i c a t i o n a c c o r d i n g t o t h i s a n a l y s i s . Each t r i a l was t h e n c l a s s i f i e d by t h e number o f n o n t a r g e t l e t t e r s i n t h e d i s p l a y t h a t were s imilar t o t h e

APPENDIX 4 . 1 95

t a r g e t a c c o r d i n g t o t h i s c r i t e r i o n . Roughly 46 , 33 , 1 3 , and 1 % of e a c h s u b j e c t ' s t r i a l s f e l l i n t o t h e c a t e g o r i e s z e r o , o n e , two, and t h r e e s i m i l a r l e t t e r s ( o t h e r t h a n t h e t a r g e t l e t t e r i t s e l f ) , r e s p e c t i v e l y .

For t h e a c c u r a c y t a s k d a t a , t h e e f f e c t of number s i m i l a r l e t t e r s was s i g n i f i c a n t . ( 3 , 39) = 7.14, p < .001. Accuracy on t a r g e t t r i a l s i n c r e a s e d some w i t h i n c r e a s e s i n t h e number of s i m i l a r l e t t e r s , whereas a c c u r a c y on c a t c h t r i a l s d e c r e a s e d s i g n i f i c a n t l y w i t h i n c r e a s e s i n t h e number of s imilar l e t t e r s , - F ( 3 , 39) = 22.28, p < .001.

For t h e RT t a s k , i n c r e a s i n g t h e number of s i m i l a r l e t t e r s produced a s i g n i f i c a n t i n c r e a s e i n RT, E ( 3 , 39) = 4.41 < .01. The i n c r e a s e was c l e a r l y l a r g e r on c a t c h t r i a l s t h a n t a r g e t t r i a l s , E ( 3 , 39) = 3.13, p < .05.

T a r g e t - c a t c h d i f f e r e n c e s . For t h e a c c u r a c y t a s k , a c c u r a c y was g r e a t e r f o r c a t c h t r i a l s ( 8 4 % ) t h a n f o r t a r g e t t r i a l s ( 7 2 % ) . E (1, 13) = 19.65, p < .001, and t h i s e f f e c t i n t e r a c t e d w i t h d i s p l a y t y p e s , ( 4 , 52) = 8.14 , < .001. O r t h o g r a p h i c s t r u c t u r e had a g r e a t e r e f f e c t on t a r g e t t h a n c a t c h t r i a l s . For t h e RT t a s k , t h e r e was a d i f f e r e n c e between t a r g e t and c a t c h t r i a l s . Catch t r i a l s were 47 msec s lower t h a n t a r g e t t r i a l s , E (1, 13) = 42.55, p < .001. However, t h i s e f f e c t d i d n o t i n t e r a c t w i t h d i s p l a y t y p e , 1 ( 4 , 52) = 1.49. T a r g e t - c a t c h d i f f e r e n c e s were a l s o r e f l e c t e d i n t h e e r r o r r a t e s i n t h e RT t a sk . T a r g e t t r i a l s e x p e r i e n c e d more e r r o r s ( 6 . 8 % ) t h a n d i d c a t c h t r i a l s ( 3 . 3 % ) , E (1, 13) = 29.88, p < .0001. There was no i n t e r a c t i o n w i t h d i s p l a y t y p e , E ( 4 , 52) = 1 . 2 4 .

96 CHAPTER 4

Appendix 4 . 1 A

Rules f o r t h e S e l e c t i o n of O r t h o g r a p h i c a l l y Regular and I r r e g u l a r S t r i n g s

These ru les were d e r i v e d by e x t e n d i n g t h e r u l e s g i v e n i n Venezky ( 1 9 7 0 ) , Venezky and Massaro (1979) , and Massaro e t a l . ( 1 9 7 9 ) . Among a l l p o s s i b l e anagrams of a word, a l e t t e r s t r i n g was regarded as o r t h o g r a p h i c a l l y i r r e g u l a r i f i t c o n t a i n e d a t l e a s t one of t h e f o l l o w i n g s p e l l i n g s :

a. p h o n o l o g i c a l l y i l l e g a l ( i n E n g l i s h ) i n i t i a l or f i n a l c l u s t e r ( e . g . , t l f ies , i a s G ) .

b. o r t h o g r a p h i c a l l y i l l e g a l s p e l l i n g for a n i n i t i a l or f i n a l consonant or consonant c l u s t e r ( e . g . , k e a g c , t l e r a v ) .

c. an i l l e g a l vowel s p e l l i n g ( e . g . , p r s a e d , n m t E ) . d . a p h o n o l o g i c a l l y i l l e g a l media l c l u s t e r ( e . g . , ilmpes,

L e t t e r s t r i n g s were regarded as r e g u l a r i f t h e y were p h o n o l o g i c a l l y l e g a l and c o n t a i n e d common vowel and c o n s o n a n t s p e l l i n g s .

i G s a ) .

APPENDIX 4 . 1 8 9 7

Appendix 4 . 1 B

The 200 S t i m u l u s Items Used i n S t u d i e s 1 - 1 0

The items l i s t e d a r e i n columns a c c o r d i n g t o t y p e , where W = word; R-H = r e g u l a r - l o w ; I-H = i r r e g u l a r - h i g h ; R-L = regular - low; and I - L = i r r e g u l a r - l o w . Each row c o n t a i n s a word and t h e f o u r anagrams g e n e r a t e d from i t .

R- H R-L I-H I - L - - Word

a c t i o n amount answer b a r e l y be long b r e a t h b r i d g e c h a r g e d o u b l e famous f i n g e r g a r d e n g a t h e r g l a n c e h a r d l y i t s e l f lawyer l o n g e r mas ter modern

c a i n o t mauton swaner b l a y e r g o b l e n t h a b e r begr i d c h a g e r bodule foamus f er i n g nagred t h a g e r c a l e n g hyr a l d s i f l e t w e r a l y l o g r e n t a m e r dormen

o n i c a t otanum erswan

g l e n o b t h e r a b g r e d i b g r e a c h e d o l u b osafum g r e f i n g r e d a n g r e a t h g l e c a n h y d r a 1 f l e s i t l y e r aw g l e r o n s t e r a m drenom

bye K a1

a i o c n t auotnm wnraes l b r a e y lnboeg b h r t e a i e r b g d ahcge r l eoubd uaomf s r f n i e g a rnged h r t a e g l c n a e g yr a h l d t l f ies rwlaey g l n o e r mr taes oermnd

i c n t o a nmtaou rnwesa r b l e y a e b g n l o r t b e h a e b r g d i h r e a g c obdeul ofmsua e f n g r i e d n r g a g r h e t a e c l n g a r d l h y a e f l s t i e y r lwa e g n r l o emr t s a rmedno

98 CHAPTER 4

APPENDIX 4 . 1 8 (COnt.)

Word

mother namely n e a r l y p e r m i t p l a y e r p o e t r y p u r e l y r e a s o n remain r e s u l t shared s i m p l e s i n g l e s p r e a d s t a r e d s t r e a m t r a v e l t r i a l s t u r n e d w i n t e r

R- H -

thomer manely l a r e n y p r ime t r a p l e y p e t o r y y u l p e r s a r o n e r amine s u r t e l s h r e a d p imsel s n i g e l p r ased s a r t e d t rames v a r t l e s a r t il d r u n e t t r iwen

R- L -

therom lyeman n y e l a r t r e p i m l y e r a p t y e r o p r y e l u p e r o s a n amer i n t r e s u l d r e a s h ems1 i p g l e s i n d r e s a p d r e s a t t resam t r e v a l t r i s a l t r e d u n t r e w i n

I-H -

mroteh lmnaey l r n a e y tmr i e p p l r aey y p t o e r l p y u e r s n a o e r mr a i e n l r t u e s s r d a e h i l m p e s i l g n e s p r saed s r t a e d m t r a e s a v r l e t i a s t l r r d n u e t w r n t e i

I -L -

hretmo emnyla enyr l a r t p e i m e p y l r a e r y t p o e r p l y u r n s e o a rniema e l s r t u h s r e d a l s e p m i n g l e s i d s e p r a d t s e r a e s r t m a t l e r a v i r l t s a e d t r n u r n t e w i

APPENDIX 4.2 99

Append ix 4 . 2

D e t a i l s o f Method, P r o c e d u r e , and R e s u l t s o f S t u d y 2 : P r e c u e v e r s u s P o s t c u e

Method

S u b j e c t s . E i g h t e e n I n t r o d u c t o r y P s y c h o l o g y s t u d e n t s , 8 ma le and 1 0 f e m a l e , p a r t i c i p a t e d f o r a n h o u r e a c h d a y o n 2 c o n s e c u t i v e d a y s and r e c e i v e d r e s e a r c h p a r t i c i p a t i o n c r e d i t t o w a r d t h e i r p s y c h o l o g y g r a d e . The d a t a f rom a n a d d i t i o n a l 1 2 s t u d e n t s was l o s t d u e t o m a c h i n e m a l f u n c t i o n s and i n a d m i s s i b l e o v e r a l l a c c u r a c y . A l l s u b j e c t s p a s s e d a p r e l i m i n a r y v i s i o n t e s t e s t a b l i s h i n g a t l e a s t 20/40 a c u i t y f o r b o t h e y e s . None o f t h e s u b j e c t s had s e r v e d i n a n y o f o u r p r e v i o u s e x p e r i m e n t s . ~- S t i m u l i and a p p a r a t u s . The s t i m u l i , a p p a r a t u s , and

d i s p l a y s e q u e n c e f o r t h e p o s t c u e t a s k were i d e n t i c a l t o t h o s e o f t h e a c c u r a c y t a s k o f S t u d y 1 d e s c r i b e d i n Appendix 4 .1 . Fo r t h e p r e c u e t a s k , a t r i a l began w i t h t h e p r e s e n t a t i o n o f t h e t a r g e t l e t t e r a t t h e l e f t o f t h e f i x a t i o n window f o r 500 msec. The t a r g e t l e t t e r was t h e n t e r m i n a t e d and 1 sec l a t e r t h e s t r i n g was d i s p l a y e d f o r t h e a p p r o p r i a t e e x p o s u r e d u r a t i o n . A f t e r d i s p l a y i n g t h e s t i m u l u s s t r i n g , t h e mask ing s t i m u l u s was s c r o l l e d i n t o v i e w and r ema ined on t h e s c r e e n u n t i l t h e s u b j e c t r e s p o n d e d . The r a n g e o f e x p o s u r e d u r a t i o n s used f o r t h e p r e c u e t a s k was 1 t o 8 c y c l e s w i t h a med ian o f 2 c y c l e s . F o r t h e p o s t c u e t a s k t h e r a n g e was 2 t o 11 c y c l e s w i t h a med ian o f 3 c y c l e s .

P r o c e d u r e . H a l f t h e s u b j e c t s r e c e i v e d t h e p r e c u e t a s k t h e f i r s t d a y and t h e p o s t c u e t a s k t h e s e c o n d day . Fo r t h e r e m a i n i n g s u b j e c t s t h i s o r d e r was r e v e r s e d . Each d a y t h e a p p r o p r i a t e t a s k was e x p l a i n e d t o t h e s u b j e c t and p e r f o r m a n c e a c c u r a c y was s t r e s s e d . S u b j e c t s were t o l d t h a t o n e - h a l f o f t h e t r i a l s would b e t a r g e t and o n e - h a l f would b e c a t c h t r i a l s . A s i n S t u d y 1, t h e tes t s e q u e n c e c o n s i s t e d o f 1 0 "yes-no" t r i a l s , 4 6 0 - t r i a l p r a c t i c e b l o c k s d u r i n g wh ich e x p o s u r e was a d j u s t e d w i t h t h e a d a p t i v e a l g o r i t h m , and ,5 8 0 - t r i a l e x p e r i m e n t a l b l o c k s d u r i n g wh ich t h e e x p o s u r e r ema ined c o n s t a n t . A l l s u b j e c t s r e s p o n d e d " y e s " t o t a r g e t t r i a l s w i t h t h e i r p r e f e r r e d hand ( r i g h t hand f o r 1 7 o f t h e 1 8 s u b j e c t s ) .

100 CHAPTER 4

Re s u l ts

O r t h o g r a p h i c s t r u c t u r e . An a n a l y s i s o f v a r i a n c e was computed from t h e s u b j e c t s ' mean a c c u r a c i e s f o r t h e 2 x 2 x 5 c o m b i n a t i o n s o f t y p e o f t a s k ( p r e c u e v e r s u s p o s t c u e ) , t r i a l t y p e ( t a r g e t v e r s u s c a t c h ) , and d i s p l a y c o n d i t i o n ( w o r d , r e g u l a r - h i g h , r e g u l a r - l o w , i r r e g u l a r - h i g h , a n d i r r e g u l a r - l o w ) . The ma in e f f e c t o f d i s p l a y t y p e was s i g n i f i c a n t , E ( 4 , 6 8 ) = 63 .57 , E < .001, a n d p l a n n e d c o m p a r i s o n s were p e r f o r m e d a s i n S t u d y 1. Words were j u d g e d 8 % more a c c u r a t e l y t h a n t h e r e g u l a r - h i g h p o s i t i o n a l - f r e q u e n c y nonwords , E (1, 6 8 ) = 34.88, E < .001. F o r t h e anagram d i s p l a y t y p e s , r e g u l a r s t r i n g s were j u d g e d 6 % more a c c u r a t e l y t h a n i r r e g u l a r s t r i n g s , (1, 6 8 ) = 42.01, E < .001. High p o s i t i o n a l - f r e q u e n c y s t r i n g s were j p d g e d 5 % more a c c u r a t e l y t h a n low p o s i t i o n a l - f r e q u e n c y s t r i n g s , E (1, 68) = 30.63, E < .001. R e g u l a r i t y and p o s i t i o n a l f r e q u e n c y d i d n o t i n t e r a c t , E (1, 6 8 ) = 1.71, p > .15. The i n t e r a c t i o n o f t y p e o f t a s k w i t h d i s p l a y c o n d i t i o n was s i g n i f i c a n t , E ( 4 , 6 8 ) = 2 .99 , p < .024. The o v e r a l l e f f e c t s o f s t r u c t u r e were g r e a t e r i n t h e p o s t c u e t h a n t h e p r e c u e t a s k . A l t h o u g h a c c u r a c y f o r i r r e g u l a r - l o w p o s i t i o n a l f r e q u e n c y was e q u i v a l e n t i n t h e two t a s k s , t h e t r e n d s d i v e r g e d s t e a d i l y w i t h i n c r e a s i n g s t r u c t u r e s o t h a t a c c u r a c y f o r words was 6% g r e a t e r i n t h e p o s t c u e t h a n t h e p r e c u e t a s k . No o t h e r i n t e r a c t i o n s a p p r o a c h e d s i g n i f i c a n c e .

S i m i l a r i t y a n a l y s e s . A p o s t hoc s i m i l a r i t y a n a l y s i s was pe r fo rmed a s i n t h e p r e v i o u s e x p e r i m e n t . The a n a l y s i s o f v a r i a n c e i n c l u d e d a s f a c t o r s t h e t y p e o f t a s k , t h e t y p e o f t r i a l ( t a r g e t v e r s u s c a t c h ) , and t h e number o f s i m i l a r l e t t e r s . T h e r e was a ma in e f f e c t o f t h e number o f s i m i l a r l e t t e r s , z ( 3 , 51) = 2 .86 , E < . 0 5 , and a s i g n i f i c a n t i n t e r a c t i o n w i t h c a t c h and t a r g e t t r i a l s , 1 ( 3 , 5 1 ) = 3 .58 , p < .025. R e l a t i v e t o t h e p r e v i o u s a c c u r a c y e x p e r i m e n t shown i n F i g u r e 4.10, t h e p r e s e n t r e s u l t s shown i n F i g u r e 4.13 r e v e a l e d much s m a l l e r d e c r e a s e s o n c a t c h t r i a l s and l i t t l e c h a n g e on t a r g e t t r i a l s w i t h i n c r e a s e s i n t h e number o f s i m i l a r l e t t e r s . The same r e s u l t s were o b s e r v e d i n t h e p r e c u e and p o s t c u e t a s k s .

T a r g e t v e r s u s c a t c h t r i a l s . N e i t h e r t h e main e f f e c t o f t y p e o f t a s k ( p r e c u e v e r s u s p o s t c u e ) n o r t r i a l t y p e ( t a r g e t v e r s u s c a t c h ) was s i g n i f i c a n t ( b o t h Es < 1 ) ; however , t h e i r i n t e r a c t i o n was s i g n i f i c a n t , (1,17) = 8 . 6 3 , E < .009. I t i s a p p a r e n t from F i g u r e 4.14 t h a t s u b j e c t s were more a c c u r a t e on t a r g e t t h a n c a t c h t r i a l s i n t h e p r e c u e c o n d i t i o n , w h e r e a s t h i s b i a s was r e v e r s e d i n t h e p o s t c u e t a s k .

APPENDIX 4.3 1 0 1

Appendix 4.3

D e t a i l s of t h e Method, P r o c e d u r e , and R e s u l t s of S tudy 3: Mixed-Case

Method

S u b j e c t s . E i g h t e e n I n t r o d u c t o r y Psychology s t u d e n t s , 3 male and 1 5 f e m a l e s , p a r t i c i p a t e d f o r an hour each day on 2 c o n s e c u t i v e d a y s and r e c e i v e d r e s e a r c h p a r t i c i p a t i o n c r e d i t . One a d d i t i o n a l s u b j e c t was l o s t f o r f a i l u r e t o complete t h e e x p e r i m e n t . A l l s u b j e c t s passed a p r e l i m i n a r y v i s i o n t e s t w i t h a t l e a s t 20/40 a c u i t y f o r bo th e y e s and no s u b j e c t had s e r v e d i n p r e v i o u s e x p e r i m e n t s .

S t i m u l i , a p p a r a t u s , p r o c e d u r e . The p r o c e d u r e and a p p a r a t u s were t h e same as i n t h e RT t a s k of S tudy 1 w i t h t h e f o l l o w i n g m o d i f i c a t i o n s . The t a r g e t l e t t e r p r e s e n t e d a t t h e beginning of each t r i a l was d i s p l a y e d i n both i t s u p p e r c a s e and l o w e r c a s e forms t o remind t h e s u b j e c t t h a t e i t h e r form might be p r e s e n t i n t h e s t i m u l u s d i s p l a y . These two l e t t e r s were shown f o r 500 msec f o l l o w e d by a 1 sec b lank i n t e r v a l and were c e n t e r e d a t what would be s e r i a l p o s i t i o n s 3 and 4 i n t h e s t i m u l u s d i s p l a y . The l e t t e r s t r i n g was t h e n d i s p l a y e d u n t i l t h e s u b j e c t responded. For a randomly s e l e c t e d one-ha l f of a l l t r i a l s , t h e f i r s t t h r e e l e t t e r s of t h e s t i m u l u s s t r i n g were p r e s e n t e d i n uppercase and t h e l a s t t h r e e l e t t e r s i n lowercase . For t h e remain ing t r i a l s t h i s o r d e r of c a s e s was r e v e r s e d .

A s i n t h e p r e v i o u s e x p e r i m e n t s , t h e s u b j e c t s s e r v e d i n two 1-hour s e s s i o n s on c o n s e c u t i v e d a y s . Each s e s s i o n c o n s i s t e d of 1 0 "yes-no" warm-up t r i a l s , 240 p r a c t i c e t r i a l s , and 400 e x p e r i m e n t a l t r i a l s . The i n s t r u c t i o n s t o t h e s u b j e c t s emphasized speed and a c c u r a c y of responding and encouraged s u b j e c t s t o t r y t o " r e a d " each d i s p l a y a s a whole a s t h e most e f f e c t i v e means of making f a s t and a c c u r a t e judgments ( J o h n s t o n & McClel land, 1 9 7 4 ) .

R e s u l t s

O r t h o g r a p h i c s t r u c t u r e . The s u b j e c t s ' mean RTs f o r t h e 10 combina t ions of t y p e of t r i a l ( t a r g e t and c a t c h ) and d i s p l a y t y p e (word, r e g u l a r - h i g h , r e g u l a r - l o w , i r r e g u l a r - h i g h , and i r r e g u l a r - l o w ) were a n a l y z e d . I n c o r r e c t t r i a l RTs and c o r r e c t t r i a l R T s exceeding 2 sec were e x c l u d e d . The e r r o r r a t e s v a r i e d between 1 . 0 % and 8 . 9 % . To d e t e r m i n e i f t h i s v a r i a b i l i t y i n

1 0 2 CHAPTER 4

e r r o r r a t e was a f f e c t i n g RT t r e n d s , t h e s u b j e c t s were ranked on e r r o r r a t e and d i v i d e d i n t o two g r o u p s ; t h e n i n e s u b j e c t s w i t h t h e l o w e s t e r r o r r a t e s formed one g r o u p and t h e remain ing s u b j e c t s t h e o t h e r . The a v e r a g e RT f o r t h e s u b j e c t s w i t h lower e r r o r r a t e s was 647 msec, whereas f o r t h e h i g h e r e r r o r r a t e s u b j e c t s , t h e mean RT was 756 msec, E (1, 16) = 3.47, p < .078. Grouping d i d n o t i n t e r a c t w i t h any o t h e r f a c t o r i n t h e a n a l y s i s .

The s i g n i f i c a n t main e f f e c t f o r d i s p l a y t y p e , E ( 4 , 64) =

65.23, p < .001, was a n a l y z e d i n t e r m s of t h e same compar isons examined i n t h e p r e v i o u s e x p e r i m e n t s . The 7 msec d i f f e r e n c e between words and r e g u l a r - h i g h pseudowords was n o t s i g n i f i c a n t , - F < 1. The compar isons among t h e anagrams r e v e a l e d t h a t t h e 30 msec d i f f e r e n c e between r e g u l a r and i r r e g u l a r anagrams was s i g n i f i c a n t , ( 1, 64) = 33.50, < .001. Also t h e 1 4 msec d i f f e r e n c e between h i g h and low p o s i t i o n a l - f r e q u e n c y items was s i g n i f i c a n t , E (1, 64) = 8.09, < .006. The i n t e r a c t i o n of r e g u l a r i t y w i t h p o s i t i o n a l f r e q u e n c y was n o t s i g n i f i c a n t , E < 1.

An a n a l y s i s of v a r i a n c e was c a l c u l a t e d on e r r o r r a t e s . T h e d i s p l a y t y p e main e f f e c t , E ( 4 , 68) = 2.86, p < .030, and t h e i n t e r a c t i o n of d i s p l a y t y p e w i t h t r i a l ( t a r g e t v e r s u s c a t c h ) , E ( 4 , 6 8 ) = 2.98, p < .025, were b o t h s i g n i f i c a n t . Although t h e t r e n d d o e s n o t seem t o be p a r t i c u l a r l y meaningfu l , t h e s o u r c e of t h e s e two e f f e c t s is t h e somewhat g r e a t e r e r r o r r a t e f o r t h e i r r e g u l a r i t e m s on t a r g e t t r i a l s .

S i m i l a r i t y a n a l y s e s . A r e s t r i c t e d s i m i l a r i t y a n a l y s i s was done on o n l y t h e l o w e r c a s e l e t t e r s i n t h e d i s p l a y s t r i n g s . Reac t ion times i n c r e a s e d 2 4 msec on c a t c h t r i a l s and d i d n o t change on t a r g e t t r i a l s wi th i n c r e a s e s from z e r o t o one s i m i l a r l e t t e r s , E (1, 1 7 ) = 5.84 , p < .05.

T a r g e t v e r s u s c a t c h t r i a l s . A s i n t h e p r e v i o u s RT t a s k , t a r g e t t r i a l s were judged more q u i c k l y (660 msec) t h a n were c a t c h t r i a l s (743 m s e c ) , E (1, 1 6 ) = 65.23, p < .001. Type of t r i a l d i d n o t i n t e r a c t w i t h t y p e of l e t t e r s t r i n g .

For t h e e r r o r d a t a , c a t c h t r i a l s ( 9 7 . 1 % ) were s i g n i f i c a n t l y more a c c u r a t e t h a n t a r g e t t r i a l s ( 9 3 . 8 % ) a s i n t h e RT d a t a of Study 1, 1 (1, 1 7 ) = 33.81, p < .001. However, t r i a l t y p e d i d i n t e r a c t w i t h d i s p l a y t y p e a s noted above.

APPENDIX 4 . 4 103

Appendix 4 . 4

D e t a i l s of Method, P r o c e d u r e , and R e s u l t s o f S tudy 4 : L imi ted Viewing T i m e

S u b j e c t s . S i x t e e n I n t r o d u c t o r y Psychology s t u d e n t s , 8 males and 8 f e m a l e s , were t e s t e d f o r a s i n g l e 90-minute s e s s i o n and r e c e i v e d r e s e a r c h p a r t i c i p a t i o n c r e d i t . A s i n t h e p r e v i o u s e x p e r i m e n t s , a l l s u b j e c t s were t e s t e d f o r v i s u a l a c u i t y of a t l e a s t 20/40, a l l responded w i t h t h e i r p r e f e r r e d hand ( r i g h t hand f o r 1 5 of t h e 1 6 ) , and no s u b j e c t had p a r t i c i p a t e d i n t h e e a r l i e r e x p e r i m e n t s .

Procedure . The s t i m u l i and a p p a r a t u s were t h e same a s t h e p r e v i o u s e x p e r i m e n t s . An e x p e r i m e n t a l t r i a l began w i t h t h e p r e s e n t a t i o n of t h e lowercase t a r g e t l e t t e r p o s i t i o n e d w i t h i n t h e viewing r e c t a n g l e a t d i s p l a y s e r i a l p o s i t i o n 4 f o r 500 msec. A 1 sec b lank i n t e r v a l f o l l o w e d and t h e n t h e s t i m u l u s s t r i n g i n l o w e r c a s e was p r e s e n t e d f o r 200 msec. The s t i m u l u s was s c r o l l e d upward and r e p l a c e d by s i x uppercase Xs which s e r v e d a s a mask and remained i n view u n t i l t h e s u b j e c t responded. Fol lowing t h e s u b j e c t ' s r e s p o n s e t h e r e was a 500 msec i n t e r t r i a l i n t e r v a l .

The t e s t i n g s e s s i o n f o r e a c h s u b j e c t c o n s i s t e d of 10 "yes-no" warm-up t r i a l s , 240 p r a c t i c e t r i a l s , and 2 4 0 0 - t r i a l e x p e r i m e n t a l s e s s i o n s . A s i n a l l p r e v i o u s e x p e r i m e n t s , t r i a l s were grouped i n t o 80 t r i a l b l o c k s . Between b l o c k s s u b j e c t s were g i v e n a minute o r two of r e s t and feedback i n t h e form of a mean RT e r r o r p e r c e n t a g e f o r t h e b l o c k . A 5 minute r e s t was g i v e n between t h e two e x p e r i m e n t a l s e s s i o n s .

The s u b j e c t s were t o l d t h a t h a l f t h e t r i a l s would be t a r g e t t r i a l s and h a l f would be c a t c h t r i a l s . They were a l s o informed t h a t t h e s t i m u l u s d i s p l a y would be b r i e f and t h a t t h e y would have t o r e a d i t c a r e f u l l y . Speed and a c c u r a c y of responding were emphasized.

O r t h o g r a p h i c s t r u c t u r e . A s i n t h e p r e v i o u s RT s t u d i e s , t h e s u b j e c t s ' mean RT f o r each c e l l of t h e d e s i g n , e x c l u d i n g i n c o r r e c t t r i a l RTs and c o r r e c t RTs exceeding 2 s e c , were a n a l y z e d . The s u b j e c t s ' e r r o r r a t e s v a r i e d between 4.5% and 1 1 . 9 % , which is h i g h e r t h a n normal ly d e s i r e d f o r RT t a s k s . For

104 CHAPTER 4

t h i s r e a s o n , s u b j e c t s were a g a i n r a n k e d by e r r o r r a t e and d i v i d e d i n t o low and h i g h e r r o r r a t e g r o u p s . An a n a l y s i s o f v a r i a n c e i n d i c a t e d no e f f e c t o f g r o u p i n g t h e s u b j e c t s by e r r o r r a t e ( a l l F s < 1 ) . The a n a l y s e s o f t h e RT d a t a i n d i c a t e d no e f f e c t o f d i s p l a y t y p e , E ( 4 , 56 ) = 1 .27 . Only t h e d i s p l a y t y p e by t r i a l t y p e i n t e r a c t i o n was s i g n i f i c a n t . The n a t u r e o f t h i s i n t e r a c t i o n may b e s e e n i n F i g u r e 4.16. T a r g e t and c a t c h R T s a p p e a r t o t r a d e - o f f a c r o s s d i s p l a y t y p e s . T h i s p a t t e r n i s i n d i c a t i v e o f a s h i f t i n b i a s , o r a t l e a s t c o n f i d e n c e , a c r o s s t h e d i s p l a y t y p e s . A s s u b j e c t s become more r e l u c t a n t ( s l o w e r ) t o r e s p o n d " y e s " t h e y become more w i l l i n g ( f a s t e r ) t o r e s p o n d "no." For t h e mos t p a r t , t h i s p a t t e r n o f d e c r e a s i n g c o n f i d e n c e c o i n c i d e s w i t h t h e d e c l i n e i n o r t h o g r a p h i c s t r u c t u r e wh ich is a r e a s o n a b l e r e a c t i o n t o d i s p l a y s t h a t a r e more d i f f i c u l t t o r e s o l v e .

An a n a l y s i s o f t h e e r r o r d a t a r e v e a l e d o n l y a ma in e f f e c t o f d i s p l a y t y p e , E ( 4 , 6 0 ) = 6 .79 , E < .001. T h i s d i s p l a y t y p e main e f f e c t was examined w i t h t h e u s u a l s e t o f c o n t r a s t s . The d i f f e r e n c e i n e r r o r r a t e be tween words and r e g u l a r - h i g h i t ems was t o o s m a l l t o b e s i g n i f i c a n t , b u t t h e 1.8% d i f f e r e n c e be tween words and t h e a v e r a g e o f t h e r e g u l a r items was s i g n i f i c a n t , (1 .60 ) = 6 . 4 2 , p < -013 . The e r r o r r a t e was 1.7% s m a l l e r f o r r e g u l a r t h a n i r r e g u l a r items, ( 1 , 6 0 ) = 8 . 5 9 , E < .005. N e i t h e r t h e p o s i t i o n a l - f r e q u e n c y e f f e c t ( e r r o r r a t e d i f f e r e n c e o f o n l y 0 . 4 % , 1 < 1) n o r t h e i n t e r a c t i o n o f r e g u l a r i t y w i t h t h e p o s i t i o n a l f r e q u e n c y were s i g n i f i c a n t , (1, 6 0 ) = 1 .30 .

S i m i l a r i t y a n a l y s e s . Fo r r e s p o n s e a c c u r a c y , t h e number o f s i m i l a r n o n t a r g e t l e t t e r s had no e f f e c t o n e i t h e r t a r g e t o r c a t c h t r i a l s , 2 ' s > .1. For RTs, t h e e f f e c t o f t h e number o f s i m i l a r n o n t a r g e t l e t t e r s had no e f f e c t o n t a r g e t t r i a l s and a l a r g e e f f e c t o n c a t c h t r i a l s , 1 ( 3 , 4 5 ) = 1 4 . 2 4 , E < .001. RTs i n c r e a s e d o n l y 1 msec on t a r g e t t r i a l s and 67 msec on c a t c h t r i a l s w i t h i n c r e a s e s f rom z e r o t o t h r e e s i m i l a r l e t t e r s .

T a r g e t - c a t c h d i f f e r e n c e s . A s i n t h e p r e v i o u s p o s t c u e RT e x p e r i m e n t s t h e r e was a ma in e f f e c t o f t r i a l t y p e , E (1, 1 4 ) = 26 .62 , E < . 001 , w i t h t a r g e t t r i a l s ( 5 6 3 msec) b e i n g r e s p o n d e d t o more q u i c k l y t h a n c a t c h t r i a l s ( 6 3 5 msec). T h e r e was a l s o t h e i n t e r a c t i o n o f t r i a l t y p e w i t h d i s p l a y t y p e d i s c u s s e d above. For t h e e r r o r d a t a , t h e r e was n e i t h e r a s i g n i f i c a n t main e f f e c t o f t r i a l t y p e , E (1, 1 5 ) = 1 . 9 5 , n o r a s i g n i f i c a n t i n t e r a c t i o n w i t h d i s p l a y t y p e , E < 1.

APPENDIX 4 . 5 105

Appendix 4.5

D e t a i l s of Method, P r o c e d u r e , and R e s u l t s of S tudy 5: Speeded RT Task w i t h Good V i s u a l I n f o r m a t i o n

Method

S u b j e c t s . E leven I n t r o d u c t o r y Psychology s t u d e n t s , 10 female and 1 male , were t e s t e d f o r a s i n g l e 1-hour s e s s i o n and r e c e i v e d r e s e a r c h p a r t i c i p a t i o n c r e d i t . S u b j e c t s were t e s t e d i n f o u r g r o u p s ; t h r e e g r o u p s w i t h t h r e e p a r t i c i p a n t s and one w i t h two. A l l s u b j e c t s responded w i t h t h e i r p r e f e r r e d hand ( r i g h t hand f o r 9 of t h e 11). No s u b j e c t had p a r t i c i p a t e d i n an e a r l i e r e x p e r i m e n t .

Appara tus 4 s t i m u l i . The s t i m u l i were t h e same a s i n t h e p r e v i o u s e x p e r i m e n t s . The v i s u a l d i s p l a y s were g e n e r a t e d by a DEC LSI-11 computer under s o f t w a r e c o n t r o l and p r e s e n t e d on T e k t r o n i x Monitor 604 o s c i l l o s c o p e s ( T a y l o r , K l i t z k e , &

MaSSaKO, 1 9 7 8 ) . These m o n i t o r s employ a P31 phosphor w i t h a decay t o .l% of s t i m u l a t e d luminance w i t h i n 3 2 msec. The a l p h a b e t c o n s i s t e d of l o w e r c a s e n o n s e r i f e d l e t t e r s r e s e m b l i n g t h e t y p e f o n t U n i v e r s 55. For a n o b s e r v e r s e a t e d c o m f o r t a b l y a t a n e x p e r i m e n t a l s t a t i o n , t h e s i x - l e t t e r d i s p l a y s subtended a b o u t 1 . 9 d e g r e e of v i s u a l a n g l e h o r i z o n t a l l y and t h e d i s t a n c e from t h e t o p of a n a s c e n d e r t o t h e bot tom of a d e s c e n d e r was a b o u t . 4 d e g r e e . T h i s computer ized l a b o r a t o r y f a c i l i t y p e r m i t t e d t h e t e s t i n g of up t o f o u r s u b j e c t s i n p a r a l l e l . Each s u b j e c t r e c e i v e d t h e same v i s u a l d i s p l a y on h i s o r her d i s p l a y m o n i t o r , and t h e computer c o l l e c t e d i n d i v i d u a l s u b j e c t ' s r e s p o n s e s .

Procedure . The e x p e r i m e n t a l p r o c e d u r e was a r e s p o n s e - s i g n a l method (Reed, 1973) i n which t h e s u b j e c t e n d e a v o r s t o respond i n synchrony w i t h a s i g n a l which, i n t h i s c a s e , was t h e o f f s e t of t h e s t i m u l u s d i s p l a y s t r i n g . The e x a c t p r o c e d u r e was a s f o l l o w s . A t r i a l began w i t h t h e p r e s e n t a t i o n of a s i n g l e f i x a t i o n p o i n t i n t h e c e n t e r of t h e s c r e e n . A f t e r 250 msec t h e f i x a t i o n p o i n t was r e p l a c e d by t h e t e s t l e t t e r f o r 500 msec. The f i x a t i o n p o i n t r e t u r n e d f o r 250 msec f o l l o w e d by t h e d i s p l a y s t r i n g . The d i s p l a y was i n i t i a l l y p r e s e n t e d f o r 550 msec w i t h t h i s v a l u e r e v i s e d e v e r y 2 0 t h t r i a l t o a c h i e v e a n o v e r a l l a c c u r a c y o f 75% f o r t h e g r o u p of s u b j e c t s be ing t e s t e d . The t r i a l t e r m i n a t e d when a l l s u b j e c t s responded o r , i n t h e e v e n t t h a t a s u b j e c t f a i l e d t o r e s p o n d , a t t h e end of 4 sec. A 500 msec i n t e r t r i a l i n t e r v a l was g i v e n . A t t h e end o f e v e r y 20

106 CHAPTER 4

t r i a l s , each s u b j e c t was g i v e n feedback a b o u t h i s o r h e r performance i n t h e f o l l o w i n g manne'r. A t t r i a l t e r m i n a t i o n t h e word FEEDBACK was p r e s e n t e d a t t h e c e n t e r of t h e s c r e e n f o r 1 s e c . One-half second l a t e r two columns of numbers appeared on t h e s c r e e n , a s u b j e c t number and t h e s u b j e c t ' s a v e r a g e d e v i a t i o n from t h e d i s p l a y s t r i n g o f f s e t t o t h e r e s p o n s e i n msec. A n e g a t i v e d e v i a t i o n i n d i c a t e d an a v e r a g e r e s p o n s e p r i o r t o t h e d i s p l a y o f f s e t : a p o s i t i v e d e v i a t i o n i n d i c a t e d t h a t t h e a v e r a g e r e s p o n s e f e l l a f t e r t h e d i s p l a y o f f s e t . Each s u b j e c t ' s number was C l e a r l y p o s t e d a t h i s o r h e r s u b j e c t s t a t i o n t o f a c i l i t a t e remembering which feedback s c o r e was a p p r o p r i a t e . The feedback s c o r e s were v i s i b l e f o r 2.5 sec a f t e r which came t h e normal h a l f second i n t e r t r i a l i n t e r v a l . The s u b j e c t s ' i n s t r u c t i o n s a c q u a i n t e d them w i t h t h e t a s k and t h e g e n e r a l t y p e s of s t i m u l u s i t e m s . I t was s t r e s s e d t h a t t h e s u b j e c t s were t o be a s a c c u r a t e a s p o s s i b l e and y e t respond a s n e a r l y i n synchrony w i t h t h e s i g n a l a s p o s s i b l e . They were t o l d how t h e y would r e c e i v e feedback and a g a i n i t was s t r e s s e d t h a t t h e y s h o u l d endeavor t o m a i n t a i n a z e r o feedback s c o r e . A l l s u b j e c t s r e c e i v e d 120 p r a c t i c e t r i a l s fo l lowed by two e x p e r i m e n t a l s e s s i o n s of 400 t r i a l s each. A s h o r t r e s t b reak was g i v e n between t h e two e x p e r i m e n t a l s e s s i o n s .

A l l s u b j e c t s became a d e p t a t t h e t a s k by t h e end of t h e p r a c t i c e t r i a l s o r e a r l y i n t h e f i r s t e x p e r i m e n t a l s e s s i o n so t h a t t h e d i s p l a y o f f s e t t imes were r e a s o n a b l y s t a b l e t h r o u g h o u t t h e two s e s s i o n s . Average d i s p l a y o f f s e t times f o r t h e f o u r groups of s u b j e c t s were a s f o l l o w s : 4 1 2 , 634, 485, and 505 msec.

R e s u l t s

S e p a r a t e a n a l y s e s were made of t h e mean a c c u r a c i e s and t h e mean R T s f o r bo th c o r r e c t and i n c o r r e c t t r i a l s . For t h e a c c u r a c y d a t a t h e r e were no s i g n i f i c a n t e f f e c t s ( a l l Fs < 1) .

The a n a l y s i s of v a r i a n c e f o r t h e R T s inc luded t r i a l t y p e , d i s p l a y c o n d i t i o n , and c o r r e c t n e s s of t h e r e s p o n s e as f a c t o r s . There were s i g n i f i c a n t e f f e c t s of t y p e of t r i a l , (1, 10) =

8.04, < .017; c o r r e c t n e s s of r e s p o n s e , r (1, 1 0 ) = 19.99 , < .001; and t h e i n t e r a c t i o n of t h e s e two f a c t o r s , (1, 1 0 34.32, < .001. These e f f e c t s were a r e s u l t of s i g n i f i c a n t l y s lower c o r r e c t c a t c h t r i a l r e s p o n s e s seen F i g u r e 4.17. Although we observed t h e normal RT advantage c o r r e c t t a r g e t t r i a l s over c o r r e c t c a t c h t r i a l s , t h e i n c o r t a r g e t and i n c o r r e c t c a t c h t r i a l s n e a r l y c o i n c i d e d w i t h

- - t h e

i n f o r e c t t h e

APPENDIX 4.5 107

c o r r e c t t a r g e t t r i a l r e s p o n s e s . The main e f f e c t o f d i s p l a y t y p e , ( 4 , 40) = 3.17, p < .023, and t h e i n t e r a c t i o n of d i s p l a y t y p e w i t h c o r r e c t n e s s of r e s p o n s e and t y p e of t r i a l , ( 4 , 4 0 ) = 3.25, < .021, were s i g n i f i c a n t . Mean RT i n c r e a s e d from 477 msec f o r words t o 492 msec f o r i r r e g u l a r - l o w nonwords.

108 CHAPTER 4

Appendix 4.6

D e t a i l s of Method, P r o c e d u r e , and R e s u l t s of Study 6: Speeded RT T a s k w i t h Poor V i s u a l I n f o r m a t i o n

Method

S u b j e c t s . T h i r t e e n I n t r o d u c t o r y Psychology s t u d e n t v o l u n t e e r s p a r t i c i p a t e d as s u b j e c t s ; t h e d a t a of two were l o s t due t o a computer m a l f u n c t i o n . A l l s u b j e c t s were n a t i v e E n g l i s h s p e a k e r s , had normal or cor rec ted- to-normal v i s i o n , had n o t p a r t i c i p a t e d i n any of t h e o t h e r e x p e r i m e n t s , were r igh t -handed , and r e c e i v e d some c r e d i t toward t h e i r c o u r s e g r a d e f o r p a r t i c i p a t i n g .

M a t e r i a l s , a p p a r a t u s , p r o c e d u r e . The s t i m u l i and a p p a r a t u s were t h e same as i n S tudy 5 and a r e d e s c r i b e d i n Appendix 4.5. The i m p o r t a n t d i f f e r e n c e i n t h e p r e s e n t exper iment is t h a t t h e comple te t e s t l e t t e r s t r i n g was r o t a t e d 180 d e g r e e s i n t h e p i c t u r e p l a n e . R o t a t i n g t h e comple te t e s t s t r i n g r a t h e r t h a n t h e i n d i v i d u a l l e t t e r s s e p a r a t e l y c r e a t e s a d i s p l a y much e a s i e r t o read ( K o l e r s , 1 9 7 0 ) . The i n i t i a l d i s p l a y d u r a t i o n was l e n g t h e n e d t o 700 msec. The t a r g e t l e t t e r was s t i l l p r e s e n t e d u p r i g h t . S u b j e c t s responded " y e s " w i t h t h e i r dominant hand.

R e s u l t s

The means among l e t t e r - s t r i n g t y p e s i n d i c a t e d a 1.1% advantage of words over t h e b e s t pseudowords ( r e g u l a r - h i g h ) and a 1 .6% advantage of words o v e r a l l t y p e s of nonwords. Accuracy f o r r e g u l a r nonwords was 0.2% b e t t e r t h a n f o r i r r e g u l a r nonwords. Nonwords of h igh p o s i t i o n a l f r e q u e n c y had a 0 .5% advantage over nonwords of low p o s i t i o n a l f r e q u e n c y . A s might be e x p e c t e d from d i f f e r e n c e s t h i s s m a l l , t h e a n a l y s i s o f v a r i a n c e i n d i c a t e d no e f f e c t of l e t t e r - s t r i n g t y p e s , E < 1. Fur thermore , t h e r e was no d i f f e r e n c e between t a r g e t and c a t c h t r i a l s , E < 1, and no i n t e r a c t i o n , < 1.

The a c c u r a c y r e s u l t s of t h e p r e s e n t e x p e r i m e n t c a n be compared t o t h o s e of S tudy 5 w i t h u p r i g h t l e t t e r s t r i n g s . T h i s a n a l y s i s i n d i c a t e d no d i f f e r e n c e s of any kind between t h e two e x p e r i m e n t s ( f o r u p r i g h t - r o t a t e d , (1, 2 1 ) = 0.14; f o r t a r g e t - c a t c h , (1, 2 1 ) = 1.18; f o r t h e u p r i g h t - r o t a t e d x t a r g e t - c a t c h i n t e r a c t i o n , 1 (1, 21) = 0.07; f o r t h e l e t t e r - s t r i n g t y p e s , E ( 4 , 84) = 0.92; f o r t h e u p r i g h t - r o t a t e d x l e t t e r - s t r i n g i n t e r a c t i o n , ( 4 , 84) = 0.09; f o r t h e

APPENDIX 4.6 109

t a r g e t - c a t c h x l e t t e r - s t r i n g i n t e r a c t i o n , 1 ( 4 , 8 4 ) = 1 .27 ; and f o r t h e th ree -way i n t e r a c t i o n , ( 4 , 8 4 ) = 0 . 2 3 ) .

An e x a m i n a t i o n o f t h e r e a c t i o n t imes i n t h e r o t a t e d e x p e r i m e n t r e v e a l e d r e s u l t s s i m i l a r t o t h o s e o f t h e a c c u r a c y d a t a . Means were c a l c u l a t e d on c o r r e c t r e a c t i o n t imes t h a t d i d n o t exceed 2 , 0 0 0 msec ( 0 . 2 5 % e x c e e d e d ) . Words were a c t u a l l y r e s p o n d e d t o 9 msec s l o w e r t h a n r e g u l a r - h i g h nonwords . R e a c t i o n t imes were 9 msec l o n g e r f o r i r r e g u l a r nonwords t h a n f o r r e g u l a r nonwords and 8 msec l o n g e r f o r nonwords o f l ow r a t h e r t h a n o f h i g h p o s i t i o n a l f r e q u e n c y .

The a n a l y s i s o f v a r i a n c e i n d i c a t e d s i g n i f i c a n t l y l o n g e r r e a c t i o n t imes f o r c a t c h t r i a l s a s compared t o t a r g e t t r i a l s , - F (1, 11) = 46 .73 , p < - 0 0 1 , b u t no e f f e c t o f t y p e s , 2 ( 4 , 44 ) = 2.43, p < . 05 , a n d no i n t e r a c t = 1 . 6 0 , p < .l.

The r e a c t i o n t imes f o r t h e r o t a t e d l e t t e r were compared t o t h o s e f o r t h e u p r i g h t l e t t e r a v e r a g e r e a c t i o n t ime f o r r o t a t e d l e t t e r s t r i n g s l o n g e r t h a n f o r u p r i g h t l e t t e r s t r i n g s , F (1, 21

1 e t te r - s t r i ng o n , 1 ( 4 , 44 )

s t r i n g s a l s o s t r i n g s . The was 104 msec = 26 .94 , p < -

.001. C a t c h t r i a l s t o o k 66 msec l o n g e r t h a n t a r g e t t r i a l s , 1 (1, 2 1 ) = 75.84, p < . 001 , b u t t h i s d i d n o t i n t e r a c t w i t h w h e t h e r t h e l e t t e r s t r i n g s were r o t a t e d , (1, 2 1 ) = 1 . 2 6 . T h e r e was a n o v e r a l l d i f f e r e n c e o f l e t t e r - s t r i n g t y p e s , - F ( 4 , 8 4 ) = 5 . 7 7 , p < .001. L e t t e r - s t r i n g t y p e s d i d n o t i n t e r a c t w i t h t h e o t h e r f a c t o r s : w i t h r o t a t i o n , ( 4 , 8 4 ) =

0.49; w i t h t a r g e t - c a t c h t r i a l s , 1 ( 4 , 8 4 ) = 1 .18 ; a n d f o r t h e t h r e e - w a y i n t e r a c t i o n , E ( 4 , 8 4 ) = 1 .18 .

To examine d i f f e r e n c e s among d i s p l a y d u r a t i o n s , t h e d i s p l a y d u r a t i o n s f o r e a c h o f t h e 40 s e t s o f 20 t r i a l s were g r o u p e d i n t o 4 b l o c k s o f 10 s e t s e a c h . Each o f t h e c o n s e c u t i v e 4 b l o c k s t h u s r e p r e s e n t e d 1 0 d i s p l a y d u r a t i o n s f o r 1 0 s e t s o f 20 t r i a l s . An a n a l y s i s o f v a r i a n c e i n d i c a t e d no d i f f e r e n c e s among b l o c k s , ( 3 , 33 ) = 0 .67 , b u t d i d i n d i c a t e a d i f f e r e n c e among t h e 10 s e t s w i t h i n a b l o c k , E ( 9 , 9 9 ) = 4.25, 2 < . 001 , and a b l o c k by s e t i n t e r a c t i o n , E ( 2 7 , 297) = 2 . 2 1 , E < .005. These e f f e c t s r e f l e c t t h e o p e r a t i o n o f b o t h p r a c t i c e and f a t i g u e . I n i t i a l l y t h e d i s p l a y d u r a t i o n s d e c r e a s e d w i t h e x p e r i e n c e , b u t t h e n i n c r e a s e d toward t h e end o f t h e f i r s t 200 t r i a l s . F o l l o w i n g a b r e a k b e t w e e n h a l v e s o f t h e e x p e r i m e n t , d i s p l a y t i m e s a g a i n d e c r e a s e d u n t i l l a t e i n t h e s e c o n d h a l f o f t h e e x p e r i m e n t .

110 CHAPTER 4

The d i s p l a y d u r a t i o n s a l s o were compared between t h e u p r i g h t and r o t a t e d e x p e r i m e n t s . Although t h e a v e r a g e d i s p l a y d u r a t i o n was 498 msec f o r u p r i g h t p r e s e n t a t i o n and 556 msec f o r r o t a t e d p r e s e n t a t i o n , t h e e f f e c t was n o t s i g n i f i c a n t , (1, 2 1 ) = 2.64, nor was t h e r e an e f f e c t of t h e b l o c k s of 10 d i s p l a y d u r a t i o n s , E ( 3 , 63) = 1 . 5 6 , and t h e two f a c t o r s a l s o d i d n o t i n t e r a c t , E ( 3 , 63) = 2.53. There were , however, d i f f e r e n c e s among i n d i v i d u a l d i s p l a y d u r a t i o n s , ( 9 , 189) = 2.05, E < .05 , and d i s p l a y d u r a t i o n s i n t e r a c t e d w i t h e v e r y t h i n g e l se : w i t h u p r i g h t - r o t a t e d l e t t e r s t r i n g s , E ( 9 , 189) = 4.65, E < .001; w i t h b l o c k s , F ( 2 7 , 567) = 1.63 , p < .05 ; and i n a three-way i n t e r a c t i o n , (27 , 567) = 1 . 6 9 , E < .05. These i n t e r a c t i o n s r e f l e c t t h e s l i g h t f a t i g u e f a c t o r in t h e r o t a t e d e x p e r i m e n t and t h e absence of such i n t h e u p r i g h t e x p e r i m e n t . For t h e u p r i g h t s t i m u l i , t h e d i s p l a y d u r a t i o n s c o n t i n u e d t o d e c r e a s e t h r o u g h o u t t h e exper iment .

APPENDIX 4.7 111

Appendix 4.7

D e t a i l s of Method, P r o c e d u r e , and R e s u l t s o f S tudy 7: High-Accuracy RT Task w i t h Poor V i s u a l I n f o r m a t i o n

Twelve s u b j e c t s were used and met t h e same c o n s t r a i n t s a s i n t h e speeded RT t a s k i n S tudy 6 (Appendix 4 . 6 ) . The same r o t a t e d s t i m u l i a l s o were used w i t h t h e f o l l o w i n g p r o c e d u r a l d i f f e r e n c e s . A t r i a l c o n s i s t e d of a 250 msec f i x a t i o n p o i n t fo l lowed by an u p r i g h t l e t t e r which was p r e s e n t e d f o r 5 0 0 msec a t t h e f i x a t i o n p o i n t and t h e n t h e r o t a t e d l e t t e r s t r i n g . The l e t t e r s t r i n g remained on t h e s c r e e n u n t i l t h e l a s t s u b j e c t ( u p t o f o u r a t a time) responded.

R e s u l t s

Means were c a l c u l a t e d f o r c o r r e c t r e a c t i o n times t h a t d i d n o t exceed 2,000 msec ( 1 . 4 % e x c e e d e d ) . R e a c t i o n times g e n e r a l l y i n c r e a s e d from words t o t h e i r r e g u l a r - l o w nonwords, - F ( 4 , 4 4 ) = 6 . 4 7 , E < .081. Regular -h igh nonwords a v e r a g e d 6 msec l o n g e r t h a n words, i r r e g u l a r nonwords r e s u l t e d i n r e a c t i o n times t h a t were 1 6 msec l o n g e r t h a n r e g u l a r nonwords, and nonwords of low p o s i t i o n a l f r e q u e n c y r e s u l t e d i n r e a c t i o n times t h a t were 18 msec l o n g e r t h a t nonwords of h igh p o s i t i o n a l f r e q u e n c y . The a v e r a g e r e a c t i o n times f o r c a t c h t r i a l s was 110 msec l o n g e r t h a n f o r t a r g e t t r i a l s , F (1, 11) = 1610.10, p < .001, b u t t h i s d i d n o t i n t e r a c t w i t h l e t t e r - s t r i n g t y p e s , 1 ( 4 ,

D i f f e r e n c e s between l e t t e r s t r i n g s were f u r t h e r examined by o r t h o g o n a l c o n t r a s t s . The d i f f e r e n c e between words and a l l nonwords was s i g n i f i c a n t , t ( 4 4 ) = 3 . 1 8 , p < .005, a s was t h e d i f f e r e n c e between r e g u l a r and i r r e g u l a r nonwords, t ( 4 4 ) =

1 . 6 8 3 , p = .05. However, t h e d i f f e r e n c e between nonwords of h igh and low p o s i t i o n a l f r e q u e n c y was n o t s i g n i f i c a n t , t ( 4 4 ) = 0 .94 . S i m i l a r l y , a Newman-Kuels t e s t i n d i c a t e d t h a t t h e 6 msec d i f f e r e n c e between words and t h e b e s t pseudowords ( r e g u l a r - h i g h ) was n o t s i g n i f i c a n t , p > .10.

A comparison of r e a c t i o n times between t h e i n i t i a l r e p l i c a t i o n e x p e r i m e n t u s i n g u p r i g h t s t i m u l i and t h e p r e s e n t s t u d y i n d i c a t e d t h a t r e a c t i o n times f o r r o t a t e d s t i m u l i averaged 2 7 9 msec l o n g e r t h a n f o r u p r i g h t s t i m u l i , (1, 2 4 ) = 4 2 . 3 5 , 2 < .0Ol. The d i f f e r e n c e between c a t c h and t a r g e t

4 4 ) = 0 .79 .

1 1 2 CHAPTER 4

t r i a l s was s i g n i f i c a n t , F (1, 24) = 1 5 3 . 4 4 , p < . 001 , a s was t h e t r i a l t y p e x r o t a t e d - u p r i g h t i n t e r a c t i o n , (1, 24) = 23.68, 2 < -001 . D i f f e r e n c e s be tween l e t t e r s t r i n g s were s i g n i f i c a n t , E ( 4 , 9 6 ) = 20.12, 2 < . 001 , b u t l e t t e r s t r i n g s d i d n o t i n t e r a c t w i t h a n y t h i n g : w i t h r o t a t e d - u p r i g h t , ( 4 , 9 6 ) = 0 .53 ; w i t h t a r g e t - c a t c h , E ( 4 , 9 6 ) = 0 . 5 3 ; and f o r t h e th ree -way i n t e r a c t i o n , ( 4 , 9 6 ) = 1.60.

APPENDIX 4.8 113

Appendix 4.8

D e t a i l s of Method, P r o c e d u r e , and R e s u l t s o f S tudy 8 : T y p i c a l i t y R a t i n g s

The o v e r t judgment e x p e r i m e n t s c o n s i s t e d of a s k i n g s u b j e c t s t o make c o n s c i o u s judgments a b o u t t h e t e s t items. Three sets of r a t i n g judgments were o b t a i n e d under s i m i l a r i n s t r u c t i o n s and a r e d e s c r i b e d h e r e a s " T y p i c a l i t y R a t i n g s . " A f o u r t h r a t i n g was o b t a i n e d i n S tudy 9 under e x p l i c i t i n s t r u c t i o n s a s t o t h e n a t u r e of p o s i t i o n a l f r e q u e n c y and is d e s c r i b e d a s " P o s i t i o n a l - F r e q u e n c y R a t i n g s . " A f i n a l s e t of judgments i n S tudy 10 were o b t a i n e d by a "Paired-Judgment" p r o c e d u r e .

Method

R a t i n g Forms. Three r a t i n g forms were p r e p a r e d . The f i r s t form employed t h e 160 anagrams; t h e second form employed t h e 160 anagrams p l u s 40 pseudowords d e r i v e d from t h e o r i g i n a l words by t h e s u b s t i t u t i o n of a s i n g l e l e t t e r ; and t h e t h i r d form used t h e e n t i r e 200 s t i m u l u s s t r i n g s i n c l u d i n g t h e o r i g i n a l words. ( S e e Appendix 4 . 1 8 f o r t h e 40 words and t h e i r 160 anagrams; see Appendix 4.8A f o r t h e o n e - l e t t e r s u b s t i t u t i o n pseudowords) . Each l i s t was randomized and p r i n t e d w i t h 20 l e t t e r s t r i n g s p e r page. The s t r i n g s were typed i n l o w e r c a s e w i t h f i v e u n d e r s c o r e s typed t o t h e r i g h t of e a c h s t r i n g a s a s p a c e f o r w r i t i n g t h e s t r i n g ' s r a t i n g . The r a t i n g s c a l e t o be used was reproduced a t t h e t o p o f each page a s f o l l o w s :

"Most l i k e E n g l i s h 10 9 8 7 6 5 4 3 2 1 L e a s t l i k e E n g l i s h . "

The f o u r or f i v e p a g e s compr is ing each l i s t were assembled i n random o r d e r i n t o b o o k l e t s . Each b o o k l e t was p r e p a r e d w i t h an a p p r o p r i a t e s h e e t of i n s t r u c t i o n s . These i n s t r u c t i o n s a r e reproduced i n Appendix 4.8B, and 4.8C.

S u b j e c t s . One hundred n i n e t y - e i g h t I n t r o d u c t o r y Psychology s t u d e n t s f i l l e d o u t one of t h r e e r a t i n g forms. The r a t e r s p a r t i c i p a t e d i n g r o u p s of 8 t o 1 2 p e r s o n s and r e c e i v e d r e s e a r c h p a r t i c i p a t i o n c r e d i t . The f i r s t 70 s u b j e c t s r a t e d t h e f i r s t form which c o n t a i n e d o n l y t h e 160 anagrams. The n e x t 65 s u b j e c t s f i l l e d o u t t h e second form which i n c l u d e d t h e 160 anagrams and t h e o n e - l e t t e r s u b s t i t u t i o n pseudowords made from t h e words. The f i n a l 63 s u b j e c t s r a t e d t h e t h i r d form which

1 1 4 CHAPTER 4

c o n t a i n e d t h e o r i g i n a l s e t o f 200 s t i m u l u s i tems ( i . e . , t h e 160 anagrams and t h e 40 w o r d s ) . Each s u b j e c t worked a t h i s o r h e r own s p e e d , and on t h e a v e r a g e , t o o k 1 5 t o 2 5 m i n u t e s t o r a t e t h e i tems.

-- P r o c e d u r e . - Each s e s s i o n began w i t h t h e e x p e r i m e n t e r r e a d i n g t h e i n s t r u c t i o n s w h i l e t h e s u b j e c t f o l l o w e d a l o n g . The f o r m a l i n s t r u c t i o n s were s u p p l e m e n t e d w i t h v e r b a l i n s t r u c t i o n s s t r e s s i n g " s i m i l a r i t y t o E n g l i s h s p e l l i n g " a s t h e p r i m a r y r a t i n g c r i t e r i o n . S u b j e c t s were u r g e d n o t t o a d o p t s t r a t e g i e s o f r a t i n g r e g u l a r i t y o n t h e b a s i s o f b e i n g a b l e t o t r a n s f o r m a s t r i n g i n t o a word t h r o u g h l e t t e r a d d i t i o n s , d e l e t i o n s , s u b s t i t u t i o n s , o r by making anagrams . The r a t e r s who r e c e i v e d t h e l i s t c o n t a i n i n g a c t u a l words were a l s o a s k e d t o d i s r e g a r d t h e s e m a n t i c c o n t e n t o f t h e words t o t h e f u l l e s t e x t e n t p o s s i b l e . F i n a l l y , t h e r e l a t i v e n a t u r e o f t h e s c a l e was s t r e s s e d . I t was i n d i c a t e d t h a t t h e p s y c h o l o g i c a l s c a l e s h o u l d s p a n t h e p r e s e n t e d s e t o f i tems and a l l 1 0 s c a l e v a l u e s s h o u l d be u s e d .

R e s u l t s

Average r a t i n g s were t a b u l a t e d b o t h w i t h i n s u b j e c t s and a c r o s s s u b j e c t s . For t h e w i t h i n s u b j e c t t a b u l a t i o n s , t h e s u b j e c t ' s r a t i n g s f o r t h e 40 s t i m u l i i n e a c h c a t e g o r y were a v e r a g e d . For t h e item a n a l y s e s , a n a v e r a g e f o r e a c h item was o b t a i n e d by a v e r a g i n g t h e r a t i n g s a s s i g n e d by e a c h s u b j e c t . T h e s e d a t a p e r m i t t e d a n a l y s e s t o d e t e r m i n e i f t h e r a t i n g s ' r e l i a b i l i t y r e f l e c t e d d i f f e r e n c e s i n mean r a t i n g s f o r t h e 4 o r 5 c a t e g o r i e s o f s t i m u l i . S i x one-way a n a l y s e s o f v a r i a n c e were computed f o r a l l p a i r w i s e c o m p a r i s o n s among t h e t h r e e i n s t r u c t i o n c o n d i t i o n s ; t h r e e a n a l y s e s were b a s e d on s u b j e c t s a s t h e s a m p l i n g v a r i a b l e and t h r e e were b a s e d on items a s t h e s a m p l i n g v a r i a b l e . The mean r a t i n g s were s o r e l i a b l e t h a t e r r o r v a r i a n c e s were u n i f o r m l y s m a l l i n a l l s i x a n a l y s e s ( s t a n d a r d e r r o r o f e s t i m a t e is t h e r a n g e o f .04 t o .68 s c a l e u n i t s f o r a l l s i x a n a l y s e s ) . With s u c h s m a l l e r r o r v a r i a n c e s , a l l p a i r w i s e d i f f e r e n c e s be tween c a t e g o r y means were r e l i a b l e a t t h e . 05 l e v e l .

A P P E N D I X 4.8A 115

Appendix 4.8A

The Pseudowords used i n S t u d y 8.

Word Pseudoword

a c t i o n amount answer b a r e l y belong b r e a t h b r i d g e c h a r g e d o u b l e famous f i n g e r g a r d e n g a t h e r g l a n c e h a r d l y i t s e l f 1 awye r l o n g e r m a s t e r modern

a p t i o n amaunt onswer p a r e l y be lang b r e e t h bradge c h u r g e g o u b l e vamous v i n g e r g u r d e n g i t h e r g l u n c e h e r d l y i t s o l f rawyer ronger moster madern

Word Pseudoword -

mother namely n e a r l y perm i t p l a y e r p o e t r y p u r e l y r e a s o n remain r e s u l t s h a r e d s imp1 e s i n g l e s p r e a d s t a r e d s t r e a m t r a v e l t r i a l s t u r n e d w i n t e r

mather nomely mear ly permat p l a d e r b o e t r y b u r e l y l e a s o n remoin r e s i l t s h a r e t sumple f i n g l e s p r e e d s t u r e d s t reem t r o v e 1 t r e a l s t a r n e d wunter

116 CHAPTER 4

Appendix 4.88

D i r e c t i o n s f o r T y p i c a l i t y R a t i n g s W i t h o u t Words and f o r T y p i c a l i t y R a t i n g s With Pseudowords

On t h e p a g e s wh ich f o l l o w a r e l e t t e r s t r i n g s made up t o l o o k l i k e E n g l i s h words . None of t h e s t r i n g s , however , is a n E n g l i s h word. Your t a s k is t o r a t e e a c h o n e o n a s c a l e o f 1 t o 1 0 a c c o r d i n g t o how much i t l o o k s l i k e a r e a l E n g l i s h word. S t r i n g s which a r e e x t r e m e l y c l o s e s h o u l d b e g i v e n h i g h r a t i n g s , w h i l e s t r i n g s which a r e n o t v e r y c l o s e s h o u l d b e g i v e n low r a t i n g s . S i n c e no r e a l words a r e i n c l u d e d , t h e h i g h e s t p o s s i b l e r a t i n g (10) s h o u l d b e g i v e n t o s t r i n g s wh ich you f e e l a r e mos t l i k e E n g l i s h words . S i m i l a r l y , a r a t i n g o f 1 s h o u l d be g i v e n t o t h e s t r i n g wh ich a r e l e a s t l i k e E n g l i s h words. The s t r i n g s h a v e b e e n s e l e c t e d t o r e p r e s e n t a l l p o s s i b l e l e v e l s o f s i m i l a r i t y t o E n g l i s h w i t h r o u g h l y e q u a l numbers a t e a c h l e v e l .

Skim o v e r t h e s t r i n g s on t h e f i r s t p a g e b e f o r e you b e g i n r a t i n g s o you h a v e a n i d e a o f t h e i r r a n g e o f v a r i a t i o n . T h e r e a r e 160(200) s t r i n g s i n a l l , d i v i d e d r andomly a c r o s s 4(5) p a g e s , s o e a c h page s h o u l d have r o u g h l y t h e same v a r i a t i o n a s a n y . o t h e r . You s h o u l d work a t a f a i r l y q u i c k and e v e n p a c e a l t h o u g h t h e r e is no t ime l i m i t .

APPENDIX 4 . 8 C 117

Appendix 4.8C

D i r e c t i o n s f o r T y p i c a l i t y R a t i n g s w i t h Words

On t h e pages which f o l l o w a r e l e t t e r s t r i n g s made up t o be s p e l l e d l i k e E n g l i s h words. Some of t h e s t r i n g s a r e , i n f a c t , E n g l i s h words, whereas o t h e r s t r i n g s a r e n o t E n g l i s h words. Independent of t h e meaning of t h e words, however, your t a s k is t o r a t e e a c h one on a sca le of 1 t o 10 a c c o r d i n g t o how much it is s p e l l e d l i k e t y p i c a l E n g l i s h s p e l l i n g . S t r i n g s which a r e e x t r e m e l y c l o s e s h o u l d be g i v e n h i g h r a t i n g s , w h i l e s t r i n g s which a r e n o t v e r y c l o s e s h o u l d be g i v e n low r a t i n g s . The h i g h e s t p o s s i b l e r a t i n g ( 1 0 ) s h o u l d be g i v e n t o s t r i n g s which you f e e l a r e s p e l l e d most l i k e E n g l i s h . S i m i l a r l y , a r a t i n g of 1 s h o u l d be g i v e n t o t h e s t r i n g s which a r e s p e l l e d l e a s t l i k e E n g l i s h . The s t r i n g s hae been s e l e c t e d t o r e p r e s e n t a l l p o s s i b l e l e v e l s of s i m i l a r i t y t o E n g l i s h s p e l l i n g w i t h r o u g h l y e q u a l numbers a t each l e v e l .

Skim o v e r t h e s t r i n g s on t h e f i r s t p a g e s b e f o r e you b e g i n r a t i n g so you have a n i d e a of t h e i r range of v a r i a t i o n . There a r e 200 s t r i n g s i n a l l , d i v i d e d randomly a c r o s s 5 p a g e s , s o each page s h o u l d have roughly t h e same v a r i a t i o n a s any o t h e r . You should work a t a f a i r l y q u i c k and even pace a l t h o u g h t h e r e is no time l i m i t .

118 CHAPTER 4

Appendix 4 . 9

The Method, P r o c e d u r e , and R e s u l t s of S tudy 9: P o s i t i o n a l - F r e q u e n c y R a t i n g s

Method

Rat ing forms were c o n s t r u c t e d by g e n e r a t i n g f r e s h c o p i e s of t h e form from Study 8 employing t h e 160 anagrams. E x p l i c i t p o s i t i o n a l - f r e q u e n c y i n s t r u c t i o n s ( r e p r o d u c e d i n Appendix 4.9A) were s u b s t i t u t e d for t h e p r e v i o u s i n s t r u c t i o n s and t h e s c a l e a t t h e t o p o f each page was modi f ied t o r e a d :

"Most f r e q u e n t 10 9 8 7 6 5 4 3 2 1 L e a s t f r e q u e n t . "

A s b e f o r e , s u b j e c t s were t e s t e d i n small g r o u p s of 8 t o 1 0 ; t h e formal i n s t r u c t i o n s were read fo l lowed by v e r b a l emphas is of t h e s a l i e n t p o i n t s o f t h e i n s t r u c t i o n s ; and s u b j e c t s were g i v e n u n l i m i t e d time a l t h o u g h t h e y u s u a l l y completed t h e form i n 1 5 t o 25 minutes . F o r t y - n i n e I n t r o d u c t o r y Psychology s t u d e n t s r a t e d t h i s form.

R e s u l t s

As i n S tudy 8 , a v e r a g e r a t i n g s were t a b u l a t e d by l e t t e r - s t r i n g t y p e f o r each s u b j e c t and f o r e a c h s t i m u l u s item a c r o s s s u b j e c t s . Two a n a l y s e s o f v a r i a n c e were computed on t h e s e d a t a and, a s i n t h e p r e v i o u s r a t i n g s , a l l p o s s i b l e p a i r w i s e comparisons of t h e f o u r anagram c a t e g o r i e s were s i g n i f i c a n t .

APPENDIX 4.9A 119

Appendix 4.9A

D i r e c t i o n s f o r P o s i t i o n a l - F r e q u e n c y R a t i n g s

I t is a r e l a t i v e l y s i m p l e m a t t e r t o d e t e r m i n e t h e f r e q u e n c y w i t h which t h e d i f f e r e n t l e t t e r s of t h e a l p h a b e t a r e used a t v a r i o u s l o c a t i o n s i n words. I t is a n o t h e r m a t t e r t o d e t e r m i n e i f p e o p l e a r e aware of t h i s " p o s i t i o n a l f r e q u e n c y . " On t h e p a g e s which f o l l o w a r e l e t t e r s t r i n g s d e r i v e d by anagramming common E n g l i s h s i x - l e t t e r words. I n some i n s t a n c e s t h e l e t t e r s have been moved t o t h e p o s i t i o n s t h e y most commonly occupy i n s i x - l e t t e r words ( h i g h f requency p o s i t i o n s ) and i n some i n s t a n c e s t h e y have been moved t o l o c a t i o n s t h a t t h e y v e r y i n f r e q u e n t l y occupy i n s i x - l e t t e r words ( low f r e q u e n c y p o s i t i o n s ) . Your t a s k is t o r a t e each s t r i n g on a s c a l e of 1 t o 10 a c c o r d i n g t o how much you b e l i e v e t h a t t h e l e t t e r s i n t h e s t r i n g occupy t h e i r most f r e q u e n t p o s i t i o n s . The h i g h e s t p o s s i b l e r a t i n g ( 1 0 ) s h o u l d be g i v e n t o t h e s t r i n g s whose l e t t e r s a r e i n t h e i r most f r e q u e n t p o s i t i o n s . The l o w e s t r a t i n g (1) s h o u l d be g i v e n t o s t r i n g s whose l e t t e r s a r e i n t h e i r l e a s t f r e q u e n t p o s i t i o n s . The s t r i n g s have been c o n s t r u c t e d s o t h a t some s t r i n g s have a l l t h e i r l e t t e r s i n t h e i r most f r e q u e n t p o s i t i o n s , some s t r i n g s have t h e i r l e t t e r s i n t h e i r l e a s t f r e q u e n t p o s i t i o n s , and t h e remain ing s t r i n g s have l e t t e r s a t a l l v a r i o u s p o s i t i o n s of g r e a t e r o r l e s s e r f r e q u e n c y . Thus you s h o u l d f i n d s t r i n g s a p p r o p r i a t e t o a l l 10 l e v e l s of t h e s c a l e w i t h r o u g h l y e q u a l numbers a t each l e v e l .

Skim over t h e s t r i n g s on t h e f i r s t page b e f o r e you b e g i n r a t i n g so you have an i d e a of t h e i r r a n g e of v a r i a t i o n . There a r e 160 s t r i n g s i n a l l , d i v i d e d randomly a c r o s s f o u r p a g e s , s o each page s h o u l d have roughly t h e same v a r i a t i o n a s any o t h e r . You s h o u l d work a t a f a i r l y q u i c k and even pace even though t h e r e is no time l i m i t .

1 2 0 CHAPTER 4

Appendix 4.10

D e t a i l s of Method, P r o c e d u r e , and R e s u l t s o f S tudy 10: R e g u l a r i t y v e r s u s P o s i t i o n a l - F r e q u e n c y Pa i red-Judgments

Method

Response forms. The pa i red- judgment forms were p r e p a r e d by f i r s t p a r t i t i o n i n g e a c h of t h e f o u r c a t e g o r i e s of anagrams i n t o f o u r randomly s e l e c t e d s u b s e t s o f 1 0 items e a c h . E i g h t y p a i r s were produced by p a i r i n g t h e 160 anagrams as f o l l o w s : One 10-i tem s u b s e t from each c a t e g o r y was matched t o a 10-i tem s u b s e t from a n o t h e r c a t e g o r y and t h e members of t h e s u b s e t p a i r e d o f f producing between c a t e g o r y p a i r s . T h i s l e f t one 10-i tem s u b s e t w i t h i n each c a t e g o r y whose members were p a i r e d w i t h each o t h e r t o form f i v e w i t h i n c a t e g o r y p a i r s . A t o t a l l i s t of 320 p a i r s was formed by per forming t h i s matching p r o c e d u r e f o u r times, r o t a t i n g t h e mating of t h e s u b s e t s w i t h i n each c a t e g o r y t o a c h i e v e a c o m p l e t e l y c o u n t e r b a l a n c e d l i s t where e v e r y i t e m was p a i r e d once w i t h a member of e v e r y o t h e r c a t e g o r y and once w i t h a member of i t s own c a t e g o r y . E i g h t such t o t a l l y d i f f e r e n t l i s t s were c o n s t r u c t e d and item b a l a n c i n g ( r i g h t - h a n d p a i r member v e r s u s l e f t - h a n d p a i r member) was randomized. The t o t a l e f f e c t was t o e n s u r e t h a t e v e r y item had a n e q u a l o p p o r t u n i t y t o be p a i r e d w i t h any o t h e r item.

Once c o n s t r u c t e d , t h e l i s t s were p r i n t e d w i t h 80 p a i r s p e r page. Each b o o k l e t was p r e f a c e d w i t h a s e t of i n s t r u c t i o n s which e i t h e r gave a d e t a i l e d d e s c r i p t i o n of r e g u l a r i t y o r p o s i t i o n a l f r e q u e n c y . I n both c a s e s , a p p r o p r i a t e examples were i n c l u d e d . The " r e g u l a r i t y " i n s t r u c t i o n s g r o u p chose t h e most r e g u l a r of each p a i r whereas t h e " p o s i t i o n a l - f r e q u e n c y ' ' i n s t r u c t i o n s g r o u p c h o s e t h e member w i t h t h e h i g h e s t p o s i t i o n a l f requency .

S u b j e c t s . F o r t y - e i g h t I n t r o d u c t o r y Psychology s t u d e n t s completed t h e pa i red- judgment t a s k . Of t h e s e r a t e r s , 2 2 r e c e i v e d " r e g u l a r i t y " i n s t r u c t i o n s and 26 r e c e i v e d " p o s i t i o n a l - f r e q u e n c y " i n s t r u c t i o n s . A l l s u b j e c t s r e c e i v e d r e s e a r c h p a r t i c i p a t i o n c r e d i t a s recompense.

Procedure . A s i n t h e p r e v i o u s r a t i n g s t u d i e s , s u b j e c t s were t e s t e d i n g r o u p s of 1 0 t o 15 and g i v e n u n l i m i t e d time t o complete t h e form. D u e t o t h e somewhat l e n g t h i e r form, s u b j e c t s took 20 t o 30 m i n u t e s t o comple te t h e form. Approximately one-half of t h e g r o u p s r e c e i v e d e x p l i c i t r e g u l a r i t y i n s t r u c t o n s (see Appendix 4.10A) , which d e s c r i b e d

APPENDIX 4.10 1 2 1

l e t t e r sequence r e g u l a r i t y , and r e q u i r e d t h a t t h e more r e g u l a r member of each p a i r be chosen . The remain ing g r o u p s r e c e i v e d e x p l i c i t p o s i t i o n a l - f r e q u e n c y i n s t r u c t i o n s ( s e e Appendix 4 . 1 0 B ) which d e s c r i b e d s i n g l e - l e t t e r p o s i t i o n a l f r e q u e n c y and r e q u i r e d t h a t t h e member of each p a i r w i t h t h e h i g h e r o v e r a l l p o s i t i o n a l f r e q u e n c y be chosen . A l l s u b j e c t s w i t h i n a g r o u p r e c e i v e d t h e same i n s t r u c t i o n s .

R e s u l t s

The p r o p o r t i o n s of times t h a t i t e m s from a n anagram c a t e g o r y were chosen over items from t h e same c a t e g o r y o r d i f f e r e n t c a t e g o r i e s a r e shown i n T a b l e 4.5. Table 4 .5 g i v e s t h e p r o p o r t i o n of times an i t e m from t h e column c a t e g o r y was s e l e c t e d when p a i r e d w i t h an i tem from t h e row c a t e g o r y . Comparing t h e two p a n e l s of Table 4.5 w e o b s e r v e t h a t s u b j e c t s i n b o t h i n s t r u c t e d c o n d i t i o n s made c h o i c e s more c o n s i s t e n t w i t h t h e a p p l i c a t i o n of r e g u l a r i t y t h a n w i t h t h e a p p l i c a t i o n of p o s i t i o n a l f r e q u e n c y a l t h o u g h both observed t a b l e s d i f f e r from t h e h y p o t h e s i z e d " p e r f e c t " outcome. Comparing t h e two p a n e l s of Table 4 .5 t o e a c h o t h e r , we see e v i d e n c e a g a i n t h a t s u b j e c t s c a n modify t h e i r judgments s l i g h t l y when g i v e n e x p l i c i t i n s t r u c t i o n s t o a t t e n d t o p o s i t i o n a l f r e q u e n c y .

122 CHAPTER 4

Appendix 4.10A

R e g u l a r i t y I n s t r u c t i o n s f o r Paired-Judgments

Our r e s e a r c h is d i r e c t e d a t d i s c o v e r i n g what it is we know a b o u t E n g l i s h words t h a t a l l o w s u s t o l o o k a t m e a n i n g l e s s s t r i n g s of l e t t e r s and judge how much t h e y resemble words. I n t r y i n g t o unders tand t h e s t r u c t u r e p r e s e n t i n words, we have focused on an i m p o r t a n t component p r o p e r t y - - r e g u l a r i t y o f l e t t e r sequencing . For example, t h e r e a r e many c o n s o n a n t sequences which begin words ( e . g . , @, a, e, th, e, e tc . ) and which end words ( e . g . , 9, el =, *, e t c . ) . There a r e common vowel sequences a s w e l l ( e . g . , 00, 9, G, sf e t c . ) . F i n a l l y , . t h e r e is r e g u l a r i t y i n how t h e s e c o n s o n a n t s and vowel g r o u p i n g s a r e t h e m s e l v e s sequenced w i t h i n words.

On t h e pages which f o l l o w a r e 320 p a i r s of m e a n i n g l e s s s i x - l e t t e r s t r i n g s which have been c o n s t r u c t e d t o v a r y a l o n g t h i s d imens ion of l e t t e r sequence r e g u l a r i t y . That is , some s t r i n g s p r e s e r v e normal l e t t e r sequencing w h i l e o t h e r s v i o l a t e normal sequencing t o a l e s s e r or g r e a t e r d e g r e e . The o b j e c t of t h i s e x p e r i m e n t is t o d e t e r m i n e t h e e x t e n t o f your knowledge by having you se lec t t h e more r e g u l a r s t r i n g i n each p a i r . You a r e t o e v a l u a t e b o t h members o f each p a i r and choose t h e one t h a t is more p e r m i s s i b l e i n te rms of r e g u l a r i t y of l e t t e r sequencing .

Before you b e g i n , s k i m o v e r t h e p a i r s on t h e f i r s t page t o g e t a f e e l f o r t h e t a s k . Once you b e g i n , t r y t o work a t a f a i r l y s t e a d y pace and n o t d w e l l t o o long on t h e p a i r s you f i n d d i f f i c u l t . You m u s t make a c h o i c e f o r each p a i r , g u e s s i n g i f n e c e s s a r y . Have you any q u e s t i o n s ?

APPENDIX 4.10B 123

Appendix 4.10B

P o s i t i o n a l - F r e q u e n c y I n s t r u c t i o n s f o r Pa i red-Judgments

Our r e s e a r c h is d i r e c t e d a t d i s c o v e r i n g what it is we know a b o u t E n g l i s h words t h a t a l l o w s u s t o look a t m e a n i n g l e s s s t r i n g s of l e t t e r s and judge how much t h e y resemble words. I n t r y i n g t o u n d e r s t a n d t h e s t r u c t u r e p r e s e n t i n words, w e have focused on an i m p o r t a n t component p r o p e r t y - - l e t t e r f r e q u e n c y . I n d i v i d u a l l e t t e r s and g r o u p s o f l e t t e r s occur w i t h v a r y i n g f r e q u e n c y a t d i f f e r e n t p o s i t i o n s w i t h i n words. For example, you can p r o b a b l y t h i n k o f words t h a t end i n fi and words t h a t end i n y, b u t fi is 10 t i m e s more f r e q u e n t t h a n y i n f i n a l p o s i t i o n . L i k e w i s e , 9 and & both occur a t t h e beginning of words, b u t is 50 times as f r e q u e n t i n i n i t i a l p o s i t i o n . I n g e n e r a l , c o n s o n a n t s a r e more f r e q u e n t t h a n vowels a t word i n i t i a l and word f i n a l p o s i t i o n s w i t h t h e e x c e p t i o n of f i n a l e , and s o on.

On t h e p a g e s which f o l l o w a r e 320 p a i r s of m e a n i n g l e s s s i x - l e t t e r s t r i n g s which have been c o n s t r u c t e d t o v a r y a l o n g t h e d imens ion of l e t t e r f r e q u e n c y by p o s i t i o n . That i s , some s t r i n g s have been c r e a t e d by p l a c i n g each l e t t e r i n i t s most f r e q u e n t p o s i t i o n i n s i x - l e t t e r E n g l i s h words. O t h e r s have t h e i r l e t t e r s p l a c e d i n l e s s f r e q u e n t p o s i t i o n s and s t i l l o t h e r s have t h e i r l e t t e r s i n t h e i r l e a s t f r e q u e n t p o s i t i o n s .

The o b j e c t of t h i s e x p e r i m e n t is t o d e t e r m i n e how w e l l you c a n judge when l e t t e r s a r e i n t h e i r most f r e q u e n t p o s i t i o n s . You a r e t o e v a l u a t e both members of each p a i r and choose t h e more " f r e q u e n t " of t h e two, e . g . , t h e s t r i n g which a p p e a r s t o have more of i ts l e t t e r s i n t h e i r more f r e q u e n t p o s i t i o n s .

Before you b e g i n , s k i m over t h e p a i r s on t h e f i r s t page t o g e t a f e e l f o r t h e t a s k . Once you b e g i n , t r y t o work a t a f a i r l y s t e a d y pace and n o t t o d w e l l t o o long on t h e p a i r s you f i n d d i f f i c u l t . You m u s t make a c h o i c e f o r e a c h p a i r , g u e s s i n g i f n e c e s s a r y . Have you any q u e s t i o n s ?

5 Structural Descriptions

To p r o v i d e a more d e t a i l e d a n a l y s i s of o r t h o g r a p h i c s t r u c t u r e e f f e c t s , we conducted p o s t hoc c o r r e l a t i o n a l a n a l y s e s of t h e p e r c e p t u a l r e c o g n i t i o n and o v e r t judgment d a t a r e p o r t e d i n Chapter 4 . The independent v a r i a b l e s were based upon v a r i o u s f r e q u e n c y and r e g u l a r i t y measures . Even though f i r m c o n c l u s i o n s might n o t be r e a c h e d , we f e l t t h a t our sample of items was s u f f i c i e n t l y l a r g e and s u f f i c i e n t l y r e p r e s e n t a t i v e t h a t t h e s e c o r r e l a t i o n a l a n a l y s e s c o u l d p r o v i d e v a l i d i n d i c a t i o n s of which measures might w a r r a n t f u r t h e r t h e o r e t i c a l and e m p i r i c a l examinat ion .

Three dependent measures were d e r i v e d from t h e e x p e r i m e n t s r e p o r t e d i n Chapter 4 f o r each o f t h e 200 s t i m u l u s items, i . e . , t h e 40 words and t h e i r 4 anagrams. The f i r s t measure was t h e mean a c c u r a c y f o r each i tem averaged a c r o s s a l l t r i a l o c c u r r e n c e s i n t h e p o s t c u e a c c u r a c y exper iment of S tudy 1: I n i t i a l R e p l i c a t i o n and t h e precue and p o s t c u e e x p e r i m e n t s of S tudy 2: P r e c u e v e r s u s P o s t c u e . A c o r r e s p o n d i n g r e a c t i o n time (RT) measure was d e r i v e d by a v e r a g i n g t h e RTs f o r a l l t r i a l o c c u r r e n c e s o f each item i n t h e r e a c t i o n time e x p e r i m e n t s of S tudy 1: I n i t i a l R e p l i c a t i o n and Study 3 : Mixed-Case. The t h i r d measure was t h e a v e r a g e r a t i n g s from one of t h e r a t i n g e x p e r i m e n t s i n S tudy 8: T y p i c a l i t y R a t i n g s . The e x p e r i m e n t was t h e one i n which t h e words t h e m s e l v e s were r a t e d a l o n g w i t h t h e 160 anagrams. Each of t h e 200 s t i m u l u s items a l o n g w i t h i t s r e s p e c t i v e a c c u r a c y , r e a c t i o n t i m e , and r a t i n g i s p r e s e n t e d i n Appendix 5.1.

As d i s c u s s e d i n Chapter 3 , a l a r g e number of measures of o r t h o g r a p h i c s t r u c t u r e based upon c o u n t s of l e t t e r , “-gram, and word f r e q u e n c i e s may be computed. Q u a n t i t a t i v e measures based upon o r t h o g r a p h i c r u l e s a r e less r e a d i l y c o n s t r u c t e d . Although

126 CHAPTER 5

we d e v i s e d and t e s t e d one measure of r e g u l a r i t y based upon t h e r u l e s o u t l i n e d i n Chapter 3 , w e c o n c e n t r a t e d upon f r e q u e n c y measures and q u e s t i o n s r e l a t e d t o t h e i r c o n s t r u c t i o n . The s p e c i f i c issues were a s f o l l o w s . Should f r e q u e n c y c o u n t s be based upon c o u n t s of word t y p e s o r word t o k e n s ? What f r e q u e n c y s c a l e g i v e s t h e most p r e d i c t i v e index of per formance , raw f requency o r some t r a n s f o r m e d f requency s c a l e such as l o g f requency? Is p o s i t i o n a l dependency, i . e . , whether t h e c o u n t s p r e s e r v e p o s i t i o n of t h e "-gram i n t h e sampled word, a n i m p o r t a n t f a c t o r ? What "-gram u n i t g i v e s t h e most powerfu l measure: s i n g l e - l e t t e r , b igram, o r t r i g r a m c o u n t s ? What is t h e c o n t r i b u t i o n of l e x i c a l s t a t u s and word f r e q u e n c y t o performance? And f i n a l l y , what method of combining t h e f r e q u e n c i e s of t h e components of a l e t t e r s t r i n g p r o v i d e t h e b e s t o v e r a l l index of i ts s t r u c t u r e ? These q u e s t i o n s w i l l be d i s c u s s e d i n t h e f o l l o w i n g s e c t i o n s .

DESCRIPTIVE MEASURES

The s o u r c e of a l l our f requency measures is a word c o r p u s sampled by Kucera and F r a n c i s ( 1 9 6 7 ) . T h i s c o r p u s c o n s i s t e d of 500 samples o f a p p r o x i m a t e l y 2,000 words e a c h s e l e c t e d from 1 5 c a t e g o r i e s . A d e s c r i p t i o n of t h e c o r p u s , i t s s e l e c t i o n , and i t s p r o c e s s i n g a r e p r e s e n t e d by Kucera and F r a n c i s . We o b t a i n e d a magnet ic t a p e of t h e word c o u n t produced from t h e c o r p u s ( i . e . , t h e "Rank L i s t " i n t h e Kucera and F r a n c i s monograph). The words were s o r t e d i n t o 10 l i s t s c o n s i s t i n g of 1- t o 1 0 - l e t t e r words r e s p e c t i v e l y . Words l o n g e r t h a n 10 c h a r a c t e r s were d e l e t e d a s were items c o n t a i n i n g numbers, p u n c t u a t i o n , o r s p e c i a l c o d i n g s f o r c a p i t a l i z a t i o n s , f o r e i g n a l p h a b e t s , and unusual g r a p h i c f e a t u r e s o r symbols. T h i s r e s u l t e d i n 10 l i s t s of words, one f o r each l e t t e r l e n g t h . These word l ists formed t h e b a s i s f o r c o u n t s of s i n g l e l e t t e r s , b igrams, and t r i g r a m s .

T a b l e s were p r e p a r e d by c o u n t i n g t h e o c c u r r e n c e of each - n-gram a t t h e p o s i t i o n it o c c u r r e d i n words o f a g i v e n l e n g t h . Two c o u n t s were o t a i n e d . One was a t y p e c o u n t based upon t h e number of word t y p e s t h a t c o n t a i n e d a g i v e n E-gram, and t h e o t h e r was a token c o u n t based upon t h e t o t a l number of o c c u r r e n c e s of t h e word c o n t a i n i n g t h e "-gram. A p o s i t i o n - i n s e n s i t i v e c o u n t ( b u t s t i l l word l e n g t h d e p e n d e n t ) was a l s o o b t a i n e d f o r each "-gram by summing a c r o s s t h e

ORTHOGRAPHIC STRUCTURE AND R E C O G N I T I O N 1 2 7

p o s i t i o n - d e p e n d e n t c o u n t s . B e c a u s e Kuce ra and F r a n c i s m a i n t a i n e d a f a i t h f u l c o u n t o f t h e a c t u a l g r a p h i c p a t t e r n s found i n t h e c o r p u s , t h e i r l i s t c o n t a i n s r a r e w o r d s , t y p o g r a p h i c e r r o r s , f o r e i g n p e r s o n and p l a c e names, and o t h e r i d e o s y n c r a t i c i t ems . To l i m i t t h e i m p a c t o f s u c h items on o u r t a b u l a t i o n s , c u t - o f f l i m i t s were e s t a b l i s h e d f o r b o t h word f r e q u e n c y and number o f s a m p l e s . The c u t - o f f s were a minimum c o u n t o f a t l e a s t o n e o c c u r r e n c e i n t h r e e o f t h e 500 s a m p l e s . Thus , u n u s u a l words and u s a g e s , r e g a r d l e s s o f t h e i r f r e q u e n c y , were i g n o r e d u n l e s s t h e y o c c u r r e d i n t h r e e o r more s e p a r a t e s a m p l e s . I n t h i s way, w o r d s w i t h t h e minimum f r e q u e n c y o f t h r e e were c o u n t e d o n l y i f t h e y o c c u r r e d o n c e i n e a c h o f t h r e e s a m p l e s . A l t h o u g h t h i s l i m i t was a r b i t r a r y , i n s p e c t i o n o f t h e word l i s t i n t h e low f r e q u e n c y r a n g e i n d i c a t e d t h a t t h e s e were r e a s o n a b l e c u t - o f f s . The s i n g l e - l e t t e r t o k e n c o u n t s f o r word l e n g t h s 3 t h r o u g h 7 and t h e b i g r a m t o k e n c o u n t s f o r word l e n g t h s 3 t h r o u g h 7 a r e p r e s e n t e d a s A p p e n d i c e s 5 .2 and 5 . 3 , r e s p e c t i v e 1 y .

A l l o f t h e f r e q u e n c y m e a s u r e s t h a t w i l l b e d i s c u s s e d were d e r i v e d from t h e s e t a b l e s w i t h two e x c e p t i o n s , word f r e q u e n c y and E n g l i s h n e s s . The f r e q u e n c i e s o f t h e 40 w o r d s were t a k e n d i r e c t l y f rom t h e Kucera and F r a n c i s c o u n t . E n g l i s h n e s s is a m e a s u r e p r o p o s e d b y T r a v e r s and O l i v i e r ( 1 9 7 8 ) and was computed from t a b l e s s u p p l i e d t o u s by t h e a u t h o r s . E n g l i s h n e s s is a c o n t i n u e d p r o d u c t o f ;-gram p r o b a b i l i t i e s e s t i m a t e d t o t h e l e v e l o f t h i r d - o r d e r t r a n s i t i o n a l p r o b a b i l i t i e s . The f o r m u l a f o r s i x - l e t t e r words o r l e t t e r s t r i n g s i s a s f o l l o w s :

E n g l i s h n e s s (#LlL2L3L4L5L6#) =

- l o g [P(L11#)*P(L2l#Ll)*P(L3lLlL2)* P(L41L2L3)*P(L51L3L4)*P(L61L4L5)1 ( 4 )

where # r e p r e s e n t s a s p a c e and L i is t h e l e t t e r a t p o s i t i o n i . The term P ( L k l L ( k - Z ) L ( k - l ) ) i s e s t i m a t e d by t h e r a t i o o f t h e t r i g r a m f r e q u e n c y o f L ( k - Z ) L ( k - l ) L k t o t h e b i g r a m f r e q u e n c y L ( k - Z ) L ( k - l ) . I t s h o u l d b e n o t e d t h a t t h e s e f r e q u e n c y e s t i m a t e s a r e n o t p o s i t i o n s e n s i t i v e e x c e p t i n a s much a s t h e y a r e t i e d t o i n i t i a l p o s i t i o n o c c u r r e n c e s , i . e . , t h e i n i t i a l t r i g r a m # L 1 L 2 and i n i t i a l b i g r a m # L 1 . The c o u n t s a r e a l s o n o t w o r d - l e n g t h s p e c i f i c . The i n i t i a l term P ( L i l # ) i n t h e f o r m u l a is a c t u a l l y t h e f r e q u e n c y o f t h e i n i t i a l l e t t e r a s i t o c c u r s i n t h e f i r s t p o s i t i o n i n words o f a n y l e n g t h . The r a t i o n a l e f o r examin ing t h i s measure is t o p r o v i d e a c o m p a r i s o n t o t h e o t h e r f r e q u e n c y m e a s u r e s we w i l l examine . T r a v e r s and O l i v i e r ( 1 9 7 8 ) p r o v i d e d some e v i d e n c e t h a t t h e m e a s u r e had success i n

128 CHAPTER 5

d e s c r i b i n g performance i n a f u l l r e p o r t o f s h o r t p r e s e n t a t i o n s of l e t t e r s t r i n g s .

Our r e g u l a r i t y measure c o n s i s t e d of a c o u n t of t h e number of i r r e g u l a r i t i e s c o n t a i n e d i n each of t h e 2 0 0 s t i m u l u s items. T h e e x a c t r u l e s f o r t h e i r r e g u l a r i t y c o u n t a r e g i v e n i n T a b l e 5 .1 . An i r r e g u l a r i t y was counted f o r e a c h v i o l a t i o n of c e r t a i n s c r i b a l c o n s t r a i n t s , f o r each i m p e r m i s s i b l e vowel c l u s t e r and f o r each i m p o s s i b l e consonant c l u s t e r when c o n s i d e r e d a s p a r t of a monosyl lab le . The items were t r e a t e d a s m o n o s y l l a b l e s because a n a p p r o p r i a t e s y l l a b i c a t i o n is d i f f i c u l t t o impose on nonsense s t r i n g s . Without r i g i d c r i t e r i a , judgments f o r some anagrams would be u n r e a s o n a b l y a r b i t r a r y . Thus, we c h o s e t o t r e a t a l l s t r i n g s a s monosyl lab ic even though t h i s r e q u i r e d c l a s s i f i c a t i o n of some two s y l l a b l e words as c o n t a i n i n g i r r e g u l a r i t i e s a t s y l l a b l e b o u n d a r i e s . The c o u n t s of i r r e g u l a r i t i e s f o r e a c h of t h e items o f e a c h of t h e f i v e s t i m u l u s c a t e g o r i e s a r e shown i n Appendix 5.1.

TYPE VERSUS TOKEN COUNTS

The f i r s t g e n e r a l i ssue i n d e r i v i n g a f r e q u e n c y measure is whether t y p e c o u n t s or t o k e n c o u n t s a r e most a p p r o p r i a t e . C e r t a i n l y , t h e two methods of c o u n t i n g w i l l produce f requency measures t h a t have some d e g r e e of c o r r e l a t i o n . Even though it is p r o b a b l y p o s s i b l e t o f i n d o c c u r r e n c e s of “-grams o c c u r r i n g i n o n l y a small number of e x t r e m e l y f r e q u e n t words and o t h e r E-grams o c c u r r i n g i n many i n f r e q u e n t word t y p e s , on t h e a v e r a g e t h e g r e a t e r t h e t y p e count t h e g r e a t e r t h e t o k e n c o u n t . Only by examining s i t u a t i o n s where t h e two measures a r e r e l a t i v e l y u n c o r r e l a t e d can t h e importance of t h e two approaches be measured. T h u s , i f our items e x h i b i t a s t r o n g c o r r e l a t i o n between type- and token-based measures l i t t l e c a n be d e t e r m i n e d from our d a t a t o s u p p o r t one over t h e o t h e r . A t t h e same time, i f our sample is r e p r e s e n t a t i v e of a wide range of l e t t e r s t r i n g s and t h e two approaches a r e h i g h l y c o r r e l a t e d , t h e q u e s t i o n may be of no p r a c t i c a l s i g n i f i c a n c e . I n any s i t u a t i o n where such a measure would be u s e f u l , e i t h e r might be used w i t h e s s e n t i a l l y i d e n t i c a l e f f e c t .

We found t h a t t h e c o r r e l a t i o n s between comparable t y p e measures and token measures f o r our sample were v e r y h i g h . Measures based on s i n g l e l e t t e r s , b igrams, and t r i g r a m s ,

ORTHOGRAPHIC STRUCTURE AND RECOGNITION 129

Table 5 . 1 The r u l e s f o r t h e i r r e g u l a r i t y c o u n t of t h e 2 0 0 s t i m u l u s i t e m s

1.

2 .

3 .

4 .

5.

6.

7.

8.

Segment s t r i n g i n t o vowel and consonant s u b s t r i n g s . T rea t f i n a l -& a s i f i t were -9. T r e a t between vowels as a ( l e g a l ) consonant .

For each consonant s t r i n g , d e t e r m i n e minimal number of vowels which m u s t be i n s e r t e d t o make t h e s t r i n g pronounceable . I n i t i a l consonant c l u s t e r s m u s t be l e g a l i n i n i t i a l p o s i t i o n . F i n a l consonant c l u s t e r s m u s t be l e g a l i n f i n a l p o s i t i o n , i n c l u d i n g t h o s e f o l l o w e d by f i n a l - e . Medial c o n s o n a n t c l u s t e r s m u s t be l e g a l i n i n i t i a l p o s i t i o n .

Rate e a c h r e s u l t i n g c o n s o n a n t s u b s t r i n g f o r p o s i t i o n - s e n s i t i v e s c r i b a l r e g u l a r i t y ( c o u n t one f o r e a c h i r r e g u l a r s u b s t r i n g ) .

For each vowel s u b s t r i n g , d e t e r m i n e minimal number of c o n s o n a n t s which m u s t be i n s e r t e d t o c r e a t e s c r i b a l l y r e g u l a r sequences . Mark a s i r r e g u l a r i l l e g a l i n i t i a l and f i n a l vowel s u b s t r i n g s .

Count number of i n s e r t e d vowels and c o n s o n a n t s , p l u s number of s c r i b a l l y i r r e g u l a r consonant and vowel s u b s t r i n g s . T h i s y i e l d s an i r r e g u l a r i t y index .

The vowel s t r i n g s ", E, s, and (among more o b v i o u s c a s e s ) would be i l l e g a l vowel s t r i n g s . y would be i l l e g a l a s a vowel i n i n i t i a l p o s i t i o n and i, 2 , a, E, and 9 would be i l l e g a l i n f i n a l p o s t i o n . is l e g a l a s is y a s a s i n g l e , n o n - i n i t i a l vowel.

- h i s n o t a l lowed i n f i n a l p o s i t i o n u n l e s s preceded by c , 9, Or S .

y and y between vowels a r e t o be counted a s c o n s o n a n t s .

1 3 0 CHAPTER 5

both p o s i t i o n s e n s i t i v e and p o s i t i o n i n s e n s i t i v e , c o r r e l a t e d between . 8 4 and .99. With such h igh c o r r e l a t i o n s no meaningfu l d i s c r i m i n a t i o n can be made between t h e two approaches . F i g u r e 5 .1 shows some 5-gram c o r r e l a t i o n s based on t y p e and t o k e n c o u n t s : t h e two s e t s of c o u n t s g i v e h i g h l y s i m i l a r c o r r e l a t i o n s . For t h i s r e a s o n , u n l e s s o t h e r w i s e s t a t e d , we w i l l d i s c u s s o n l y measures based on t o k e n c o u n t s i n t h e remainder of t h i s c h a p t e r .

SCALE OF FREQUENCY

T h i s a n a l y s i s c o n c e r n s t h e f requency s c a l e t o be chosen i n computing f requency measures . While t h e e f f e c t s of f r e q u e n c y

Accuracy

0 Bigram Trigram B

I I I

LINEAR LOG LINEAR LOC

TYPE TOKEN

F i g u r e 5 . 1 C o r r e l a t i o n s of a c c u r a c y and r e a c t i o n times a s a f u n c t i o n of l i n e a r o r l o g and t y p e o r t o k e n p o s i t i o n - s e n s i t i v e s i n g l e - l e t t e r , b igram, and t r i g r a m c o u n t s .

ORTHOGRAPHIC STRUCTURE AND RECOGNITION 1 3 1

seem t o be p s y c h o l o g i c a l l y r e a l , i t is n o t n e c e s s a r y t h a t t h e m e n t a l r e p r e s e n t a t i o n s o f f r e q u e n c y d i r e c t l y r e f l e c t t h e f r e q u e n c y o f o b j e c t i v e c o u n t s . One a l t e r n a t i v e s c a l e t h a t h a s b e e n s u c c e s s f u l i n o t h e r r e s e a r c h i s a l o g a r i t h m i c ( b a s e 10) s c a l e . Not o n l y a r e t h e r e some d a t a t o s u g g e s t t h e p o s s i b i l i t y o f a l o g a r i t h m i c r e p r e s e n t a t i o n (Solomon 6, Pos tman , 1952 ; T a y l o r , 1977 ; T r a v e r s & O l i v i e r , 1 9 7 8 ) , b u t a l s o a l o g a r i t h m i c r e p r e s e n t a t i o n is c o n s i s t e n t w i t h r e c e n t s t u d i e s o f number r e p r e s e n t a t i o n ( S h e p a r d , 1 9 7 8 ) and w i t h many o t h e r p s y c h o l o g i c a l s c a l e s . T h e r e f o r e , w e computed a l l o f o u r f r e q u e n c y m e a s u r e s b a s e d upon b o t h r e g u l a r l i n e a r f r e q u e n c i e s and l o g f r e q u e n c i e s . F o r t h e s e m e a s u r e s , and a l l t r a n s f o r m e d s c a l e s ( t o b e d i s c u s s e d ) , l i n e a r - f r e q u e n c y t a b l e s f o r t h e p o s i t i o n - d e p e n d e n t "-grams were n o t r e s c a l e d b e f o r e m e a s u r e s were computed f o r a n y i tem. T h e r e f o r e , t h e two s e t s o f m e a s u r e s b e i n g c o r r e l a t e d were s u m s o f p o s i t i o n - d e p e n d e n t s i n g l e l e t t e r s , b i g r a m s , and t r i g r a m s d e r i v e d from e i t h e r l i n e a r - f r e q u e n c y o r l o g - f r e q u e n c y t a b l e s . I n n e a r l y e v e r y i n s t a n c e t h e l o g - f r e q u e n c y m e a s u r e was more h i g h l y c o r r e l a t e d w i t h t h e p e r f o r m a n c e m e a s u r e t h a n was l i n e a r f r e q u e n c y ( s e e , f o r e x a m p l e , F i g u r e 5 . 1 ) .

A l t h o u g h l o g f r e q u e n c i e s , f o r p u r p o s e s o f d e s c r i b i n g t h e e f f e c t s o f o r t h o g r a p h i c s t r u c t u r e on r e c o g n i t i o n p e r f o r m a n c e , were b e t t e r t h a n l i n e a r f r e q u e n c i e s , w e were a l s o i n t e r e s t e d i n compar ing t h e l o g s c a l e w i t h o t h e r t r a n s f o r m a t i o n s o f t h e l i n e a r f r e q e n c i e s . For t h i s i n v e s t i g a t i o n , w e c h o s e o u r b e s t f r e q u e n c y m e a s u r e , summed t o k e n p o s i t i o n - s e n s i t i v e b i g r a m s , and a p p l i e d a r a n g e o f t r a n s f o r m a t i o n s t o i t . A power f u n c t i o n o f t h e form

X y = a (5)

g a v e v a r i o u s s c a l e s d e p e n d i n g on t h e v a l u e o f t h e e x p o n e n t x . E x p o n e n t s o f 0 . 8 , 0 . 7 , 0 . 5 , 0 . 2 , and 0 . 1 were s e l e c t e d . The 0 .2 e x p o n e n t a p p r o x i m a t e s t h e l o g f u n c t i o n v e r y c l o s e l y i n t h e r a n g e o f f r e q u e n c y v a l u e s r e p r e s e n t e d by o u r s t i m l u i . The l a r g e r e x p o n e n t s y i e l d e d v a l u e s i n t e r m e d i a t e be tween t h o s e o f t h e l i n e a r and l o g s c a l e s w h i l e t h e 0 . 1 e x p o n e n t p roduced v a l u e s more e x t r e m e t h a n t h e l o g f u n c t i o n . The c o r r e l a t i o n b e t w e e n t h e s e b i g r a m m e a s u r e s and t h r e e p e r f o r m a n c e m e a s u r e s g rew m o n o t o n i c a l l y f rom t h e l i n e a r s c a l e m e a s u r e t o t h e l o g and 0.2 e x p o n e n t power f u n c t i o n where c o r r e l a t i o n s peaked and t h e n f e l l f o r ' t h e more e x t r e m e 0.1 e x p o n e n t power f u n c t i o n . The c o r r e l a t i o n s be tween a v e r a g e a c c u r a c y and t h e s e b i g r a m m e a s u r e s were . 6 3 f o r t h e l i n e a r s c a l e ; .77 f o r t h e l o g s c a l e ; and .68,

132 CHAPTER 5

.70, .74 , .77 , .75 f o r exponents of 0 . 8 , 0 .7 , 0 . 5 , 0 .2 , and 0 . 1 r e s p e c t i v e l y . These d a t a i n d i c a t e t h a t i f f requency measures a r e u t i l i z e d by t h e r e a d e r , t h e y appear t o be computed on l o g f r e q u e n c i e s , and so o n l y log- f requency measures w i l l be d i s c u s s e d f u r t h e r .

POSITION-SENSITIVE VERSUS POSITION-INSENSITIVE COUNTS

There have been many a t t e m p t s t o d e r i v e a measure of p e r c e p t a b i l i t y based upon p o s i t i o n - i n s e n s i t i v e f r e q u e n c y c o u n t s (Gibson 1964; Gibson, e t a l . , 1970; Postman & Conger, 1954; Spoehr & Smith , 1 9 7 5 ) . These a t t e m p t s have t y p i c a l l y shown t h a t c o u n t s t h a t accumula te f r e q u e n c i e s w i t h o u t r e g a r d t o p o s i t i o n g i v e i n a d e q u a t e measures . On t h e o t h e r hand, p o s i t i o n - s e n s i t i v e measures have r e c e i v e d some s u p p o r t as y i e l d i n g b e t t e r measures (Gibson e t a l . , 1970; Mason, 1975, McClelland & J o h n s t o n , 1 9 7 7 ) . We compared t h e two t y p e s of measures a g a i n s t our d a t a . Table 5 .2 shows t h e c o r r e l a t i o n s between t h e t h r e e per formance measures w i t h s i n g l e - l e t t e r , b igram, and t r i g r a m c o u n t s d e r i v e d from both p o s i t i o n - s e n s i t i v e and p o s i t i o n - i n s e n s i t i v e c o u n t s . The s t r i k i n g d i f f e r e n c e i n t h i s t a b l e is between t h e two d i f f e r e n t s i n g l e - l e t t e r measures . A s noted by e a r l i e r r e s e a r c h e r s ( e . g . , Postman & Conger, 1 9 5 4 ) , o v e r a l l l e t t e r f r e q u e n c y w i t h o u t r e g a r d t o p o s i t i o n i s n o t a v e r y powerfu l p r e d i c t o r of r e c o g n i t i o n performance. By c o n t r a s t , a p o s i t i o n - d e p e n d e n t s i n g l e - l e t t e r measure is a l m o s t a s powerfu l a s p o s i t i o n - i n s e n s i t i v e b igrams and t r i g r a m s f o r d e s c r i b i n g a c c u r a c y and RT. I t s h o u l d be noted t h a t p o s i t i o n - i n s e n s i t i v e c o u n t s d o b e t t e r a s t h e =-gram's l e n g t h i n c r e a s e s . For "-grams of a g i v e n l e n g t h , p o s i t i o n dependence seems t o l e a d t o a b e t t e r index of s t r u c t u r e a l t h o u g h t h e advantage is e s s e n t i a l l y e l i m i n a t e d f o r t r i g r a m c o u n t s . The a p p a r e n t s u p e r i o r i t y of p o s i t i o n - s e n s i t i v e bigrams over p o s i t i o n - s e n s i t i v e t r i g r a m s w i l l be d i s c u s s e d n e x t . For t h e remainder of t h e s e a n a l y s e s , p o s i t i o n - s e n s i t i v e c o u n t s w i l l be used.

ORTHOGRAPHIC STRUCTURE A N D RECOGNITION 1 3 3

T a b l e 5 .2 C o r r e l a t i o n s be tween t h e t h r e e d e p e n d e n t m e a s u r e s and summed l o g f r e q u e n c y c o u n t s , b o t h p o s i t i o n d e p e n d e n t and p o s i t i o n i n d e p e n d e n t .

!&pe o f F r e q u e n c y Measure Dependen t M e a s u r e s

RT R a t i n q A c c u r a c y - P o s i t i o n I n d e p e n d e n t

S i n g l e L e t t e r . 2 0 - . 3 6 . 0 4

Bigram . 5 9 - .55 . 7 3

T r i g r a m . 6 8 - .57 . 8 4

P o s i t i o n Dependen t

S i n g l e L e t t e r . 6 2

Bigram . 7 7

T r i g r am . 7 5

- .48 . 4 5

- . 6 4 . 8 3

- . 5 4 . 8 0

THE MOST EFFECTIVE FREQUENCY MEASURE

We h a v e n o t e d t h a t summed p o s i t i o n - s e n s i t i v e l o g b i g r a m f r e q u e n c i e s had t h e h i g h e s t c o r r e l a t i o n s w i t h our t h r e e p e r f o r m a n c e m e a s u r e s . T h i s measure, i n f a c t , had t h e h i g h e s t c o r r e l a t i o n s o f a n y of t h e a l m o s t 5 0 f o r m s o f f r e q u e n c y m e a s u r e s t h a t w e examined . Fo r e x a m p l e , p o s i t i o n - s e n s i t i v e s i n g l e l e t t e r s a c c o u n t f o r a n a v e r a g e o f 2 9 % o f t h e v a r i a n c e i n o u r t h r e e p e r f o r m a n c e m e a s u r e s , w h i l e p o s i t i o n - s e n s i t i v e b i g r a m s a c c o u n t f o r 5 7 % . A l t h o u g h it m i g h t b e e x p e c t e d t h a t l a r g e r !-grams s h o u l d n a t u r a l l y c a p t u r e more o r t h o g r a p h i c s t r u c t u r e t h a n s m a l l e r E-grams, we o b s e r v e d t h a t p o s i t i o n - s e n s i t i v e b i g r a m c o u n t s o f s e v e r a l k i n d s ( d i s c u s s e d be low) were b e t t e r t h a n c o m p a r a b l e f r e q u e n c y m e a s u r e s b a s e d

1 3 4 CHAPTER 5

upon t r i g r a m s . I t is p o s s i b l e t o h y p o t h e s i z e s e v e r a l r e a s o n s why t h i s s h o u l d be t h e c a s e . F i r s t , t h e sampling e r r o r i n t h e t r i g r a m t a b l e s may be l a r g e enough r e l a t i v e t o t h e sampling e r r o r i n t h e bigram t a b l e s t o a c c o u n t f o r t h e e f f e c t . The rough e q u i v a l e n c e between p o s i t ion- independent and p o s i t i o n - d e p e n d e n t t r i g r a m c o u n t s might have r e s u l t e d from a t r a d e - o f f between t h e a d v a n t a g e of p o s i t i o n s e n s i t i v i t y and t h e l a r g e r e r r o r v a r i a n c e f o r p o s i t i o n - s e n s i t i v e c o u n t s . Second, t r i g r a m s s imply may have reached a p o i n t of d i m i n i s h i n g r e t u r n s . With b igrams a c c o u n t i n g f o r 5 7 % of t h e v a r i a n c e , t h e r e s imply may be no room f o r n o t i c e a b l e improvements w i t h l a r g e r "-gram measures . F i n a l l y , i t c o u l d be t h a t bigram c o u n t s a r e more r e p r e s e n t a t i v e of t h e r e a d e r ' s knowledge and u t i l i z a t i o n of o r t h o g r a p h i c s t r u c t u r e . We w i l l r e t u r n t o t h i s q u e s t i o n i n a l a t e r s e c t i o n of t h i s c h a p t e r .

The measures t h a t have been d i s c u s s e d were based upon t h e s u m of t h e f r e q u e n c i e s f o r t h e component "-grams i n a l e t t e r s t r i n g . E n g l i s h n e s s was d e s c r i b e d a s a p r o d u c t of f r e q u e n c y r a t i o s and would appear t o p r o v i d e an i n t e r e s t i n g comparison i n te rms of how a f r e q u e n c y measure s h o u l d be computed from component "-gram f r e q u e n c i e s . The o b s e r v a t i o n t h a t l o g f requency i s a b e t t e r s c a l e narrows t h e d i s t a n c e between E n g l i s h n e s s and summed "-gram measures s i n c e E n g l i s h n e s s is computed a s t h e s u m o f t h e l o g a r i t h m s of f requency r a t i o s . I n a c t u a l compar ison , E n g l i s h n e s s proved t o be a l e s s powerfu l measure t h a n t h e p o s i t i o n - d e p e n d e n t bigram measure. I t c o r r e l a t e d - . 6 5 w i t h a v e r a g e a c c u r a c y , . 4 7 w i t h a v e r a g e RT, and - . a 2 w i t h t h e r a t i n g s .

I t o c c u r r e d t o u s t h a t t h e n o r m a l i z a t i o n p r o c e s s of d i v i d i n g a t r i g r a m f r e q u e n c y by t h e t o t a l f requency o f a l l r e l a t e d t r i g r a m s might have t h e p o t e n t i a l f o r producing an e x t r e m e l y powerfu l measure. That is e s s e n t i a l l y what E n g l i s h n e s s does e x c e p t t h a t it is based upon p o s i t i o n - i n s e n s i t i v e c o u n t s . T h i s would make p a r t i c u l a r l y good t h e o r e t i c a l s e n s e i n t h e case where p a r t i a l v i s u a l i n f o r m a t i o n was a v a i l a b l e and was used t o r e s o l v e O K e s t i m a t e unknown l e t t e r s . For example, i f some t r i g r a m xyz is c o n s i d e r e d a t some p o i n t i n a l e t t e r s t r i n g , t h e p r e d i c t a b i l i t y of z g i v e n t h e p r e c e e d i n g l e t t e r s xy is a f u n c t i o n of t h e f r e q u e n c y of xyz r e l a t i v e t o t h e t o t a l f r e q u e n c y of a l l t r i g r a m s xy-, where t h e f i n a l l e t t e r r a n g e s over t h e e n t i r e a l p h a b e t and t a k e s on a l l a c t u a l l y o c c u r r i n g v a l u e s . Of c o u r s e , c o n s t r a i n t s need n o t work o n l y f o r w a r d , t h e r a t i o s xyz/x-z and xyz/-yz a r e a l s o of i n t e r e s t . Analogously, r a t i o s of p a r t i c u l a r bigrams xy t o t h e g e n e r a l bigram s u m s x- and -y c a n be computed.

ORTHOGRAPHIC STRUCTURE AND R E C O G N I T I O N 1 3 5

T a b l e 5.3 C o r r e l a t i o n s between t h e per formance measures and summed bigram, E n g l i s h n e s s , and c o n s t r a i n t - r a t i o measures a l l based on l o g word-token f r e q u e n c i e s .

Frequency Measure Performance Measure

RT R a t i n g Accuracy -

Summed Bigrams .77 - .64 . 8 5

E n g l i s h n e s s - .65 .47 - . 8 2

X Y d X Y - .75 - .55 . 8 1

X Y z/x-z . 7 4 -. 56 . 8 2

X Y 4 - Y . 7 4 - .54 .80

XY/X- .76 - .64 . 8 6

XY1-Y .75 - .64 . 8 5

These f i v e c o n s t r a i n t r a t i o s s u g g e s t f i v e p o t e n t i a l l y i n t e r e s t i n g measures d e r i v e d by summing t h e f o u r t r i g r a m c o n s t r a i n t r a t i o s o r f i v e bigram c o n s t r a i n t r a t i o s f o r our s i x - l e t t e r s t r i n g s . Again, t h e measures were computed a s r a t i o s of l i n e a r f r e q u e n c i e s and a s r a t i o s of l o g f r e q u e n c i e s . The c o u n t s c o u l d be based on word-type f r e q u e n c i e s o r word-token f r e q u e n c i e s . I n t h i s c a s e , y e t a n o t h e r t y p e f r e q u e n c y i s p o s s i b l e , l e t t e r - t y p e f r e q u e n c y . L e t t e r - t y p e f r e q u e n c y i s s imply t h e number of l e t t e r s t h a t a c t u a l l y occur i n t h e f r e e v a r i a b l e p o s i t i o n . Thus, a t r i g r a m of t h e form s-r might c o n s i s t of a f a m i l y of e i g h t o r n i n e t r i g r a m s w h i l e q-i h a s o n l y a s i n g l e p o s s i b l e member. L e t t e r - t y p e f r e q u e n c y was t a k e n a s t h e r e c i p r o c a l number of t r i g r a m s i n a f a m i l y o r z e r o i f t h e f a m i l y h a s no n a t u r a l l y o c c u r r i n g member, i . e . , a l l i l l e g a l t r i g r a m s . A s i m i l a r l e t t e r - t y p e measure was c o n s t r u c t e d f o r b igrams. I n a l l , t h e r e were 3 0 measures computed from c o n s t r a i n t r a t i o s ( f i v e k i n d s of r a t i o s x two f r e q u e n c y s c a l e s x t h r e e k i n d s o f t y p e and t o k e n c o u n t s ) .

136 CHAPTER 5

The r e s u l t s f o r t h e s e c o n s t r a i n t - r a t i o measures m i r r o r e d t h e r e s u l t s f o r t h e s i m p l e summed fi-gram f r e q u e n c i e s . R a t i o s o f l o g f r e q u e n c i e s c o n s i s t e n t l y gave h i g h e r c o r r e l a t i o n s t h a n r a t i o s o f l i n e a r f r e q u e n c i e s . Word-token f r e q u e n c i e s and word-type f r e q u e n c i e s were n e a r l y i n d i s t i n g u i s h a b l e i n terms o f t h e i r c o r r e l a t i o n s w i t h t h e per formance measures ; t h e s e f requency measures c o r r e l a t e d w i t h each o t h e r a t .90 o r h i g h e r . L e t t e r - t y p e f r e q u e n c i e s c o r r e l a t e d s l i g h t l y less h i g h l y w i t h word-type and word-token f requency measures b u t a l s o d i d n o t c o r r e l a t e a s h i g h l y w i t h t h e performance measures . F i n a l l y , t h e bigram r a t i o measures gave s l i g h t l y h i g h e r c o r r e l a t i o n s wi th t h e performance measures t h a n d i d t h e t r i g r a m r a t i o s . A

r e p r e s e n t a t i v e sample of t h e s e measures i s shown i n T a b l e 5 .3 . C o r r e l a t i o n s among t h e f r e q u e n c y measures were q u i t e h i g h . The t h r e e t r i g r a m measures shown i n Table 5 . 3 c o r r e l a t e d w i t h e a c h

.a -

.6 -

.4 -

H . 2 -

B d . o - K K 0 -.2 - 0

-.4 - -.6 - - . 8 - o Blgram

x Trlgram

-1.0 I I I I I I I 1 2 3 4 5 6

SERIAL POSITION

F i g u r e 5 .2 C o r r e l a t i o n s o f a c c u r a c y and r e a c t i o n t i m e s w i t h s i n g l e - l e t t e r , b igram, and t r i g r a m f r e q u e n c i e s a s a f u n c t i o n of t h e i r r e s p e c t i v e s e r i a l p o s i t i o n s i n t h e s i x - l e t t e r s t r i n g s .


o t h e r .98 or h i g h e r . L ikewise , t h e two bigram c o n s t r a i n t - r a t i o measures c o r r e l a t e d . 9 9 w i t h e a c h o t h e r . Given t h e u n i f o r m l y h igh c o r r e l a t i o n s between a l l t h e c o n s t r a i n t - r a t i o measures , i t i s i m p o s s i b l e t o d i s c r i m i n a t e among them. Fur thermore , t h e s e r a t i o s d o n o t a c c o u n t f o r any more v a r i a n c e t h a n t h e c o m p u t a t i o n a l l y s i m p l e r summed l o g bigram measure. For t h e s e r e a s o n s , t h e summed l o g bigram measure is t o be p r e f e r r e d over t h e c o n s t r a i n t r a t i o s .

Having found t h a t computing more complex measures was no more e f f e c t i v e t h a n summing t h e component bigrams of a l e t t e r s t r i n g , w e i n v e s t i g a t e d a s i m p l e r measure. We examined t h e c o r r e l a t i o n s of t h e f r e q u e n c i e s of each of t h e component - n-grams w i t h t h e per formance measures . Thus, t h e r e were s i x c o r r e l a t i o n s f o r s i n g l e - l e t t e r f r e q u e n c i e s , f i v e f o r bigram f r e q u e n c i e s , and f o u r f o r t r i g r a m f r e q u e n c i e s w i t h each

.3 t

.2 - 0

8 .l- o” 0

g 40-

30-

20 -

- 6

-6

- 4

K

- 6

SERIAL POSITION

F i g u r e 5 . 3 V a r i a n c e s of s i n g l e - l e t t e r and bigram o c c u r r e n c e s a long w i t h t h e i r observed c o r r e l a t i o n s w i t h a c c u r a c y measures a t t h e r e s p e c t i v e s e r i a l p o s i t i o n s i n t h e s i x - l e t t e r s t r i n g s .

138 CHAPTER 5

p e r f o r m a n c e m e a s u r e . F i g u r e 5.2 p r e s e n t s t h e r e s u l t s o f t h i s a n a l y s i s . A l t h o u g h some o f t h e i n d i v i d u a l "-grams d i d n e a r l y a s we l l a s t h e summed m e a s u r e s , no s i n g l e "-gram u n i t had a s h i g h a c o r r e l a t i o n a s i ts c o r r e s p o n d i n g summed m e a s u r e . I t i s a p p a r e n t f rom t h e f i g u r e t h a t t h e end l e t t e r p o s i t i o n s were t h e mos t i m p o r t a n t , b u t a s t h e 3-gram l e n g t h i n c r e a s e d t h e p o s i t i o n a l d i f f e r e n c e s w e re d i m i n i s h e d .

F i g u r e 5.2 shows t h a t t h e d e g r e e t o wh ich a p a r t i c u l a r - n-gram p r e d i c t s p e r f o r m a n c e is c r i t i c a l l y d e p e n d e n t o n i t s s e r i a l p o s i t i o n , e s p e c i a l l y f o r t h e s i n g l e - l e t t e r and t o some e x t e n t t h e b i g r a m c o u n t s . I n o r d e r t o e v a l u a t e w h e t h e r t h i s e f f e c t i s d u e t o t h e i n f o r m a t i o n a l c o n s t r a i n t s i n t h e s t i m u l i t h e m s e l v e s , w e d e r i v e d a m e a s u r e a f r e d u n d a n c y o r p r e d i c t a b i l i t y f o r e a c h s e r i a l p o s i t i o n . The v a r i a n c e o f l e t t e r o c c u r r e n c e s a t e a c h s e r i a l p o s i t i o n was computed b a s e d on t h e t a b l e o f f r e q u e n c i e s g i v e n i n Appendix 5 . 2 a n d 5.3. H igh v a r i a n c e s o c c u r t o t h e e x t e n t t h a t some l e t t e r s o c c u r more o f t e n t h a n o t h e r s . T h e s e v a r i a n c e m e a s u r e s f o r t h e s i n g l e - l e t t e r and b ig ram c o u n t s a r e shown i n F i g u r e 5.3. A s m i g h t b e e x p e c t e d from p h o n o l o g i c a l and s c r i b a l c o n s t r a i n t s , l e t t e r s a r e much more p r e d i c t a b l e i n i n i t i a l and f i n a l p o s i t i o n s t h a n i n t h e m i d d l e o f s i x - l e t t e r words. A l s o p r e s e n t e d i n F i g u r e 5 . 3 a r e t h e c o r r e s p o n d i n g c o r r e l a t i o n s w i t h t h e a c c u r a c y m e a s u r e . The v a r i a n c e and c o r r e l a t i o n m e a s u r e s a r e h i g h l y c o r r e l a t e d f o r s i n g l e - l e t t e r c o u n t s which means t h a t s u b j e c t s e x p l o i t r e d u n d a n c y d i r e c t l y t o t h e d e g r e e t h a t i t i s p r e s e n t . A l though t h i s c o r r e s p o n d e n c e m i g h t b e e x p e c t e d t o o c c u r n e c e s s a r i l y , t h e b ig ram r e s u l t s a r g u e t h e o p p o s i t e . A l t h o u g h t h e v a r i a n c e m e a s u r e s a r e r o u g h l y s i m i l a r f o r t h e f i r s t t h r e e s e r i a l p o s i t i o n s , t h e c o r r e l a t i o n s a r e much h i g h e r f o r t h e f i r s t two p o s i t i o n s t h a n f o r t h e t h i r d . I n a d d i t i o n , a l t h o u g h t h e f i n a l b ig ram is much more p r e d i c t a b l e t h a n t h e p e n u l t i m a t e b i g r a m , t h e c o r r e l a t i o n s d o n o t d i f f e r by much.

FREQUENCY VERSUS R E G U L A R I T Y

A m a j o r c o n c e r n o f t h e p r e s e n t r e s e a r c h h a s b e e n t o compare f r e q u e n c y w i t h r u l e - g o v e r n e d r e g u l a r i t y a s i n d i c e s o f s t r u c t u r e . We have d i s c u s s e d i n C h a p t e r 3 t h e form of e x p e r i m e n t a t i o n t h a t w i l l need t o b e c o n d u c t e d t o f u r t h e r d i f f e r e n t i a t e t h e s e two i n d i c e s . We h a v e p r e s e n t e d e v i d e n c e i n


Chapter 4 t h a t r e g u l a r i t y i s a t l e a s t a s i m p o r t a n t f o r p e r c e p t u a l r e c o g n i t i o n and more i m p o r t a n t f o r o v e r t judgments a s is s i n g l e - l e t t e r p o s i t i o n a l f r e q u e n c y . I n t h e p r e s e n t c h a p t e r , w e have shown t h a t s i n g l e - l e t t e r p o s i t i o n a l f r e q u e n c y is a good measure b u t t h a t bigram p o s i t i o n a l f r e q u e n c y i s a b e t t e r measure. W e have examined s e v e r a l d imens ions of t h e f r e q u e n c y domain and p r e s e n t e d s e v e r a l f i n d i n g s a b o u t f r e q u e n c y measures . T h i s i n v e s t i g a t i o n of t h e q u a n t i t a t i v e a s p e c t s of f r e q u e n c y measures was r e l a t i v e l y d i r e c t and s t r a i g h t f o r w a r d .

A comparable i n v e s t i g a t i o n i s n o t p o s s i b l e f o r r e g u l a r i t y . We have made o n l y a v e r y modest s t a r t . A s an i n i t i a l e f f o r t t o q u a n t i f y r e g u l a r i t y , w e computed a s i m p l e c o u n t of o r t h o g r a p h i c i r r e g u l a r i t i e s based upon our p r e l i m i n a r y a t t e m p t a t a grammar of o r t h o g r a p h y ( s e e Table 5 . 1 ) . The r e s u l t d o e s r a t h e r w e l l i n c o r r e l a t i n g w i t h per formance measures b u t is n o t s u f f i c i e n t l y deve loped t o a l l o w f o r a d e c i s i v e comparison w i t h bigram f r e q u e n c y . The r e g u l a r i t y c o u n t c o r r e l a t e d .57 w i t h a v e r a g e a c c u r a c y , - . 53 w i t h a v e r a g e RT, and .85 w i t h t h e r a t i n g s . Although t h e s e c o r r e l a t i o n s w i t h t h e two r e c o g n i t i o n measures a r e q u i t e modest i n comparison w i t h t h e f r e q u e n c y measures d e s c r i b e d i n t h i s c h a p t e r , t h e c o r r e l a t i o n w i t h r a t i n g s i s comparable w i t h t h e b e s t f r e q u e n c y measure. While we h e s i t a t e t o draw s t r o n g c o n c l u s i o n s , i t would appear t h a t t h e r e is p o t e n t i a l f o r d e v e l o p i n g n o t o n l y r e f i n e d ru le -governed measures b u t a l s o q u a n t i t a t i v e l y u s e f u l s t r u c t u r e i n d i c e s based upon t h e s e r u l e s .

One major problem w i t h d i s t i n g u i s h i n g between f r e q u e n c y and r e g u l a r i t y measures of o r t h o g r a p h i c s t r u c t u r e is t h a t t h e s e two measures a r e n a t u r a l l y c o r r e l a t e d i n t h e w r i t t e n language . I t is p o s s i b l e t o u n t a n g l e t h e s e measures a s we d i d i n t h e p r e s e n t s t u d i e s . However, by i n d e p e n d e n t l y v a r y i n g s i n g l e - l e t t e r p o s i t i o n a l f r e q u e n c y and r e g u l a r i t y , we a c t u a l l y c r e a t e d l e t t e r s t r i n g s t h a t v a r i e d s y s t e m a t i c a l l y w i t h bigram f r e q u e n c y . Our r e g u l a r s t r i n g s were h i g h e r i n bigram f r e q u e n c y t h a n t h e c o r r e s p o n d i n g i r r e g u l a r s t r i n g s . T h e r e f o r e , r e g u l a r i t y and p o s i t i o n - s e n s i t i v e l o g bigram f r e q u e n c y c o r r e l a t e d . 7 5 9 i n our l i s t of 2 a 8 t e s t i t e m s . I n f u t u r e e x p e r i m e n t s , w e p l a n t o i n d e p e n d e n t l y v a r y t h e s e two measures of o r t h o g r a p h i c s t r u c t u r e i n p e r c e p t u a l r e c o g n i t i o n and o v e r t judgment e x p e r i m e n t s .

140 CHAPTER 5

W I T H I N CLASS ANALYSIS

A l l of t h e a n a l y s e s p r e s e n t e d s o f a r i n t h i s c h a p t e r have examined c o r r e l a t i o n s between measures computed f o r t h e items a c r o s s t h e f i v e c l a s s e s of s t i m u l u s s t r i n g s . Whereas i t is v e r y i m p o r t a n t t o e x p l a i n t h i s between c l a s s v a r i a n c e , i t is e q u a l l y i m p o r t a n t t o examine how w e l l s e v e r a l measures of o r t h o g r a p h i c s t r u c t u r e e x p l a i n t h e v a r i a n c e w i t h i n e a c h c l a s s . To do t h i s , t h e c o r r e l a t i o n a l a n a l y s e s were r e p e a t e d s e p a r a t e l y f o r t h e words and t h e r e g u l a r - h i g h , r e g u l a r - l o w , i r r e g u l a r - h i g h , and i r r e g u l a r - l o w anagram c l a s s e s . F i g u r e 5 . 4 p r e s e n t s t h e c o r r e l a t i o n s f o r t h e t h r e e p o s i t i o n - s e n s i t i v e l o g

'":

.4

-.6

-.8 c

3 Bigram x Trigram

Reaction Time

-1.0 WORDS R-H R-L I-H I-L

F i g u r e 5 . 4 C o r r e l a t i o n s of a c c u r a c y and r e a c t i o n times a s a f u n c t i o n of s i n g l e - l e t t e r , b igram, and t r i g r a m f r e q u e n c i e s f o r each o f t h e f i v e - l e t t e r s t r i n g t y p e s .

ORTHOGRAPHIC STRUCTURE A N D RECOGNITION 1 4 1

n-gram c o u n t s w i t h t h e a c c u r a c y and RT p e r f o r m a n c e m e a s u r e s . A s c a n be s e e n i n t h e f i g u r e , t h e m o s t s i g n i f i c a n t r e s u l t is t h e r e l a t i v e l y p o o r c o r r e l a t i o n s o f p e r f o r m a n c e w i t h t r i g r a m f r e q u e n c i e s . S i n g l e l e t t e r and b i g r a m f r e q u e n c i e s d o a b o u t e q u a l l y w e l l o v e r a l l . F i n a l l y , a l l c o r r e l a t i o n s f o r t h e word RT d a t a were c l o s e t o z e r o . T h i s l a t t e r r e s u l t m i g h t i n d i c a t e t h a t l e x i c a l s t a t u s makes a u n i q u e c o n t r i b u t i o n i n t h e RT t a s k a t t e n u a t i n g t h e c o n t r i b u t i o n s o f o r t h o g r a p h i c s t r u c t u r e . F u t u r e r e s e a r c h w i l l b e n e c e s s a r y t o a d d r e s s t h i s i s s u e .

WORD FREQUENCY

An a d d i t i o n a l m e a s u r e o f i n t e r e s t i s word f r e q u e n c y . Word f r e q u e n c y h a s shown t o b e a good p r e d i c t o r o f word r e c o g n i t i o n ( B r o a d b e n t , 1 9 6 7 ) . Log word f r e q u e n c y c o r r e l a t e s .64 w i t h a v e r a g e a c c u r a c y a n d .62 w i t h r a t i n g s ; h o w e v e r , f o r j u s t t h e word i t e m s t h e c o r r e l a t i o n s a r e - .27 and -.11 r e s p e c t i v e l y . T h i s means t h a t word f r e q u e n c y c a n n o t b e d i r e c t l y r e s p o n s i b l e f o r t h e e f f e c t s o f o r t h o g r a p h y s i n c e much h i g h e r c o r r e l a t i o n s s h o u l d h a v e b e e n s e e n i n t h e c l a s s o f words . I n f a c t , a dummy v a r i a b l e a s s i g n i n g t h e v a l u e 1 t o a l l words and 0 t o a l l nonwords c o r r e l a t e s . 6 6 w i t h a v e r a g e a c c u r a c y a n d .63 w i t h r a t i n g s . Log word f r e q u e n c y c o r r e l a t e s .52 a n d .78 w i t h p o s i t i o n - s e n s i t i v e l o g b i g r a m and t r i g r a m f r e q u e n c i e s r e s p e c t i v e l y i n o u r s e t o f 200 i tems. T h e r e f o r e , l e x i c a l s t a t u s i t s e l f a p p e a r s t o c o n t r i b u t e v e r y l i t t l e beyond wha t c a n b e a c c o u n t e d f o r b y s u b l e x i c a l o r t h o g r a p h i c s t r u c t u r e .

YULTI P L E REGRESS1 ON

A s e r i e s o f m u l t i p l e r e g r e s s i o n a n a l y s e s were c a r r i e d o u t t o see how much o f t h e v a r i a n c e o f e a c h o f t h e d e p e n d e n t m e a s u r e s c o u l d b e a c c o u n t e d f o r b y some c o m b i n a t i o n o f d e s c r i p t i v e m e a s u r e s . F o r r e s p o n s e a c c u r a c y , l o g b i g r a m f r e q u e n c y , l o g word f r e q u e n c y , a n d l o g s i n g l e - l e t t e r f r e q u e n c y a c c o u n t e d f o r a t o t a l o f 68% o f t h e v a r i a n c e . No o t h e r d e s c r i p t i v e v a r i a b l e improved o n t h e 4 0 % o f t h e RT v a r i a n c e a c c o u n t e d f o r by l o g b i g r a m f r e q u e n c y . F i n a l l y , 88% o f t h e

1 4 2 CHAPTER 5

v a r i a n c e o f t h e r a t i n g j u d g m e n t s was a c c o u n t e d f o r by r e g u l a r i t y c o u n t , l o g t r i g r a m f r e q u e n c y , and l o g word f r e q u e n c y . These r e s u l t s show t h a t t h e knowledge o f o r t h o g r a p h i c s t r u c t u r e r e v e a l e d by a n o v e r t j udgmen t t a s k d o e s n o t r e v e a l i t s e l f t o t h e same d e g r e e i n p e r c e p t u a l r e c o g n i t i o n t a s k s . T h i s r e s u l t is n o t u n r e a s o n a b l e c o n s i d e r i n g t h e a d d i t i o n a l v i s u a l p r o c e s s i n g r e q u i r e m e n t s i n t h e p e r c e p t u a l r e c o g n i t i o n t a s k s . I n a d d i t i o n , t h e a c c u r a c y t a s k a l l o w s a s i g n i f i c a n t l y l a r g e r c o n t r i b u t i o n o f o r t h o g r a p h i c s t r u c t u r e t h a n d o e s t h e RT t a s k . The r e a s o n f o r t h i s d i f f e r e n c e a p p e a r s t o b e d u e t o t h e r e l a t i v e l y s m a l l c o n t r i b u t i o n o f v i s u a l p r o c e s s i n g t o t h e RT m e a s u r e compared t o t h e r e l a t i v e l y l a r g e c o n t r i b u t i o n o f v i s u a l p r o c e s s i n g t o t h e a c c u r a c y m e a s u r e ( s e e C h a p t e r 4 ) .

SUMMARY

The p o s t hoc c o r r e l a t i o n s were r e a s o n a b l y s u c c e s s f u l i n i l l u m i n a t i n g t h e r o l e o f a number o f v a r i a b l e s r e l e v a n t t o m e a s u r e s o f o r t h o g r a p h i c s t r u c t u r e . Type and t o k e n c o u n t s were e q u a l l y good m e a s u r e s f o r o u r s t i m u l u s i t ems , w h e r e a s l o g c o u n t s were s i g n i f i c a n t l y b e t t e r t h a n l i n e a r c o u n t s . P o s i t i o n s e n s i t i v i t y i s c r i t i c a l , e s p e c i a l l y f o r s m a l l e r !-gram c o u n t s . F i n a l l y , p o s i t i o n - s e n s i t i v e l o g b ig ram f r e q u e n c y a p p e a r e d t o b e t h e mos t e f f e c t i v e m e a s u r e , a l t h o u g h t h e r e a p p e a r s t o b e some p o t e n t i a l f o r d e v e l o p i n g a n e q u a l l y good r e g u l a r i t y m e a s u r e .

A P P E N D I X 5 .1 143

Append ix 5 .1

S t i m u l u s Items and R e s u l t s

Each o f t h e 2 0 0 s t i m u l u s items and i t s r e s p e c t i v e a v e r a g e p e r c e n t a g e a c c u r a c y (Acc) , a v e r a g e RT, ave r . age r a t i n g , summed p o s i t i o n - se n s i t i v e l o g s i ng le- 1 e t t e r f r e q u e n c y , summed PO s- i t i o n - s e n s i t i v e l o g b i g ram f r e q u e n c y , summed p o s i t i o n - s e n s i t i v e l o g t r i g r a m f r e q u e n c y , l o g word f r e q u e n c y , and number o f i r r e g u l a r i t i e s .

1 4 4

WORDS

a c t i o n amount answer b a r e l y b e l o n g b r e a t h b r i d g e c h a r g e d o u b l e famous f i n g e r g a r d e n g a t h e r g l a n c e h a r d l y i t s e l f l a w y e r l o n g e r m a s t e r modern mothe r namely n e a r l y p e r m i t p l a y e r p o e t r y p u r e l y r e a s o n remain r e s u l t s h a r e d s imp1 e s i n g l e s p r e a d s t a r e d s t r e a m t r a v e l t r i a l s t u r n e d w i n t e r

Acc %

8 1 7 7 8 9 8 9 8 9 8 6 9 4 8 6 9 2 8 9 9 2 9 3 8 9 8 7 8 9 7 9 8 6 9 4 9 3 9 3 9 3 90 8 9 8 3 9 5 9 3 9 2 8 5 8 5 8 6 9 3 9 1 9 1 9 1 9 5 8 9 85 8 2 8 5 9 1

RT R a t i n g msec

644 6 56 6 4 4 6 3 5 6 0 3 6 2 9 6 5 4 6 4 2 6 2 1 6 3 9 6 5 3 6 1 9 6 7 3 637 6 6 1 6 3 7 646 6 2 7 6 2 7 6 1 6 6 1 0 6 6 2 6 2 0 590 6 1 9 6 4 2 6 0 7 605 6 3 8 6 3 6 6 4 0 6 2 2 6 3 2 6 1 1 6 7 2 6 1 6 6 2 2 6 2 3 6 7 5 6 2 1

8.8 9.3 8.2 9.3 9.5 9.3 8.9 9.4 8.9 8.9 9.5 9.7 9.4 9.3 9.4 9.2 8.7 9.6 9.7 9.5 9.5 9.4 9.3 9.6 9.6 9.2 9 .1 9 . 1 9 .5 9.7 9.4 9.4 9.2 9.2 9.4 9.5 9.6 9.2 9.3 9.7

CHAPTER 5

S i n g l e Bigram T r i g r a m Le t t e r

22.33 15.26 21.83 14.12 22.10 14 .08 23.30 1 5 . 6 3 22 .76 1 5 . 1 2 21.48 1 3 . 5 6 21.94 13 .05 22.28 1 4 . 5 1 22.13 13.56 22.05 13 .34 22.80 15.58 22 .75 14 .26 22.87 1 5 . 9 1 21.77 13 .70 22.49 14.87 21.03 1 3 . 6 3 21.60 12 .50 22.96 15.67 23.55 1 6 . 5 6 22.33 1 4 . 4 0 2 3 . 3 1 16 .47 22.53 14.84 22.52 14.76 22.52 14 .16 21 .85 1 4 . 6 1 22.80 12 .36 23.03 15 .85 22.46 15.60 22.19 1 4 . 4 2 23.02 14.56 23.55 15.92 22.94 1 5 . 0 1 23.02 14.58 22.60 1 3 . 4 2 23.44 16 .32 21.94 1 4 . 1 9 21.87 1 3 . 5 1 22.53 12 .64 23.42 15 .57 2 3 . 1 1 16.34

10.98 9.67 8.87 9.59 7 .99 8.36 8.58 9 . 6 1 7 .94 8.56 9 .78 9 .04

10.23 8.94 9 .06

1 0 . 2 5 6.99

10.20 10.54

9.64 1 1 . 1 0

8 .22 9 .47 9 . 0 1 9.47 8.09 9.33

1 0 . 7 6 9.15 9.74 9.74

10.78 9.30 8.78

10.10 9 .85 8.53 7.07

1 0 . 7 4

Word F r e q .

2.46 2 .24 2 .18 1.49 1.57 1.72 1.99 2.09 1 .75 1.95 1.60 1.78 1.30 1 .60 2.03 2.48 1 . 6 3 2.29 1 .86 2.30 2.33 1.52 2.15 1.89 1 . 7 1 1.94 1 .48 2.38 1.97 2.39 1 .60 2 . 2 1 2.24 1.92 1.78 1 . 7 1 1 .79 1 .59 2 . 5 1

10.32 1 . 9 2

# o f 1 r r .

1 0 1 0 0 0 0 0 0 0 0 1 0 0 2 1 0 0

0 0 0 0 1 1 0 1 0 0 0 0 0 1 0 0 0 0 0 0 1 1

APPENDIX 5.1

REGULAR-HIGH

1 4 5

c a i n o t mau ton s w a n e r b l a y e r g o b l e n t h a b e r b e g r i d c h a g e r b o d u l e foamus f e r i n g n a g r e d t h a g e r c a l e n g h y r a l d s i f l e t w e r a l y l o q r e n t a s m e r dormen t home K

m a n e l v l a r e n y p r i m e t r a p l e v p e t o r y y u l p e r s a r o n e r a m i n e s u r t e l s h r e a d p i m s e l s n i g e l p r a s e d s a r t e d t r a m e s v a r t l e s a r t i l d r u n e t t r i w e n

ACC

%

8 2 70 81 8 1 8 1 7 8 7 8 8 6 7 7 74 8 3 8 3 7 2 77 6 9 7 2 8 1 7 9 77 8 7 8 7 87 79 8 1 88 89 74 8 3 8 2 8 2 7 9 8 1 8 1 8 7 9 1 8 0 79 70 8 1 7 2

RT R a t i n g msec

6 4 5 620 615 666 638 6 37 640 673 6 7 3 670 617 659 612 659 677 640 649 604 648 625 654 639 656 629 634 6 4 5 662 6 3 5 6 0 5 610 675 6 4 1 604 639 622 582 638 672 636 672

6 .5 7 .5 7 .6 8.0 8 .6 7 .6 7.8 8 . 3 8 . 0 7 . 3 7 .7 7.0 7 .7 5.6 6.6 7.7 5.7 7 .4 7 .3 8 . 2 7 .3 8 .4 7 .2 8.0 7 .7 7 .3 8.0 7 .8 8 .2 7 .3 9 . 2 7 .7 6.8 8.4 8 . 4 8 . 3 7 .2 7 . 3 6 . 8 6.6

S i n g l e L e t t e r

22.69 22.49 22 .25 21.79 21.94 22 .42 22 .27 22.90 22 .78 21 .80 23.22 22.66 22.70 22.85 21 .84 23 .06 22.87 22.53 22 .92 22 .92 22.68 22.96 23.15 22.64 22.49 23.13 21 .17 23 .83 23 .29 23 .43 23 .19 22.48 22 .42 23 .18 24.44 22.80 22 .95 22 .85 22.49 21.90

Biqram T r i g r a m

13 .74 13 .54 13 .40 1 3 . 7 8 1 3 . 3 5 1 4 . 9 5 12 .89 15 .27 13 .92 10 .39 15 .85 13 .74 1 5 . 2 9 15 .50

9 .21 1 2 . 6 9 13 .87 12 .07 13 .94 14 .56 15 .54 1 5 . 3 3 14 .18 13 .97 11 .86 1 4 . 1 2 10 .87 1 4 . 6 3 14 .84 14 .64 13 .92 11 .77 12 .58 15 .33 16 .02 1 4 . 1 1 1 5 . 0 1 12 .89 13 .05 11 .54

4 .38 2 .28 5 .50 8 . 1 4 3 .60 5 .14 3.96 7 .54 2 .63 0 .00 9 . 7 3 4.75 6 .39 6 .17 3 .10 5 .33 3.36 3 .89 3 .87 6 .00 8 . 4 1 8 .76 5 .68 4 .78 2 .62 5 .36 5.09 6.14 8 . 4 2 5 . 2 3 7 .94 2 .36 1 .34 6 .16 6 .87 7 .74

3.90 2 .81 1.90

8 .74

Word # o f FKeq. I K K .

0 . 00 0 0 .00 0 0 .00 0 0 .00 0 0 .00 0 0 .00 0 0 .00 0 0.00 0 0 .00 0 0 .00 0 0 .00 0 0 .00 0 0 .00 0 0 .00 0 0 .00 0 0 .00 0 0 .00 0 0 .00 0 0 .00 0 0 .00 1 0 .00 0 0 .00 0 0 .00 0 0 .00 0 0 .00 0 0 .00 0 0 .00 1 0 .00 0 0.00 0 0.00 1 0 .00 0 0 .00 1 0 .00 0 0 .00 0 0 .00 1 0 .00 0 0.00 1 0 .00 1 0 .00 0 0 .00 0

1 4 6 CHAPTER 5

REGULAR-LOW

AC C

%

o n i c a t 7 1 otanum 59

e r s w a n 7 1 b y e r a l 7 7 g l e n o b 7 9 t h e r a b 7 5 g r e d i b 6 6 g r e a c h 6 8 e d o l u b 6 8 osa fum 5 3 g r e f i n 8 1 g r e d a n 8 5 g r e a t h 8 3 g l e c a n 8 1 h y d r a 1 7 2 f l e s i t 7 1 l y e r a w 7 3 g l e r o n 8 0 s t e r a m 7 9 drenom 7 5 t he rom 8 0 lyeman 6 6 n y e l a r 7 7 t r e p i m 7 3 l y e r a p 7 5 t y e r o p 7 2 r y e l u p 7 3 e r o s a n 7 3 a m e r i n 7 7 t r e s u l 7 4 d r e a s h 7 3 ' e m s l i p 7 3 g l e s i n 7 1 d r e s a p 7 5 d r e s a t 8 7 t r e s a m 7 6 t r e v a l 8 4 t r i s a l 7 1 t r e d u n 7 2 t r e w i n 7 9

RT R a t i n g msec

637 6 .5 6 6 8 6.9 675 6.0 6 6 7 4.8 6 6 0 7.3 6 6 6 7.0 6 7 2 5.9 6 4 8 8.7 6 7 9 5.3 6 6 9 4.4 6 3 3 7.0 6 5 3 7.0 6 0 1 8 .1 6 4 8 6.5 6 5 4 7.6 6 2 1 7.6 6 9 0 6.8 6 2 1 8.0 6 2 6 7.6 6 2 7 7 . 1 6 5 8 7.6 6 9 3 8.1 6 5 6 5.3 6 4 5 7.2 7 0 2 5.9 6 4 7 5.3 6 8 4 6 . 1 6 2 1 6.9 6 3 8 7.0 6 3 6 6.9 6 8 6 7.9 638 6.7 6 3 2 7 . 1 6 5 2 6.8 6 4 7 6.3 6 3 5 7.0 6 6 3 8 . 1 608 7 . 1 6 4 1 7.7 6 5 1 7.3

S i n g l e Le t t e r

20.84 20.12 21 .01 20.60 19 .23 19.48 18.96 21.03 17.97 1 8 . 4 1 20.20 21.13 21.00 20.67 19.92 21.38 19.87 21.27 21 .21 21.10 21.07 20.53 20.64

20.67 19 .08 19.29 18.59 21.72 20.78 20.74 21.211 18.97 20.90 19.73 21.54 20.79 20.78 21.33 20.99 20.91

Bigram T r i q r a m

1 0 . 3 1 0.60 12.46 2.65

8 .35 0.00 8.29 1.20 9.63 1.74 9.68 3.39

10.13 5.34 13.62 5.69

4.79 0.00 5.98 0 .00

12.27 4.80 13.02 4.13 1 3 . 6 6 8 . 1 1 1 0 . 8 6 0.00

6.68 1.20 11 .58 1.00

6.87 0.00 1 2 . 3 2 2.12 11.08 2.84 1 2 . 9 3 3.93 12.72 3.39

9.64 2.16 7.45 1.95

10 .67 1.74 6.47 0.00 7.49 0.00 4.56 0.00

11.75 1.08 11.53 1.26 11.28 2.22 1 2 . 2 9 6.56

6.56 1.32 11 .50 2.71

9.52 2.48 1 1 . 2 1 2.48 11.26 2.52 1 1 . 9 1 1.74 13 .45 4.13

9.29 3.55 10.96 2.34

Word # o f F r e q . I r r .

0.00 0 0.00 0 0.00 1 0.00 1 0.00 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 1 0.00 0 0.00 0 0.00 0 0.00 0 0.00 1 0.00 1

0.00 0 0.00 1 0.00 1 0.00 1 0.00 0 0.00 0 0.00 0 0.00 0 0.00 1 0.00 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 0

A P P E N D I X 5.1

I R R E G U L A R - H I G H

1 4 7

a i o c n t auotnm wnraes l b r a e y lnboeg b h r t e a i e r b g d a h c g e r leoubd uaomf s r f n i e g a rnged h r t a e g l c n a e q y r a h l d t l f i es rwlaey g l n o e r m r t a e s oermnd mroteh lmnaey l r n a e y t m r i e p p l r a e y y p t o e r l p y u e r s n a o e r mra ien l r t u e s s r d a e h i lmpes i l g n e s p r s a e d s r t a e d m t r a e s a v r l e t i a s t l r r d n u e t w r n t e i

Acc %

6 3 69 7 0 8 1 6 5 7 5 66 7 1 7 6 6 1 7 0 8 4 7 0 6 7 6 1 68 7 3 7 8 7 6 7 1 8 2 7 0 69 68 8 4 7 0 6 8 7 5 7 5 7 1 6 7 7 4 68 8 5 8 6 7 2 7 4 8 1 7 5 6 3

RT Rat ing msec

6 5 6 6 5 2 6 6 6 6 9 9 6 9 2 6 6 4 7 2 8 674 6 9 1 6 9 8 6 5 6 6 6 3 6 6 3 675 6 8 1 6 6 4 688 6 6 2 657 650 660 7 0 5 6 4 8 6 6 2 573 6 9 2 6 7 1 6 4 5 6 1 2 6 5 6 680 635 6 5 8 6 2 3 6 7 5 6 4 7 6 5 6 6 5 0 7 1 2 6 9 6

3 . 1 3.7 2.4 3.0 2 . 1 1.5 2.3 3.0 2.5 2.0 2.2 3.8 2.3 2.2 2.4 2.6 2.1 2.9 2.3 2.8 2.8 2.6 2.8 2.7 2.9 2.6 3.0 4.3 3.4 2.0 2 . 1 3.8 4.5 3.3 2.2 2.3 4.4 2.6 2 .1 2.4

S i n g l e L e t t e r

22.36 22.07 22.93 21.76 21.87 22.22 21.96 22.64 21.38 20.03 22.21 22.98 22.50 22.06 21.14 22.89 21.52 22.42 23.27 22.62 22.84 21.74 22.70 20.72 22.96 21.13 21.70 2 3 . 4 1 23.27 23.34 22.36 22.08 22.00 23.25 23.75 23.20 21 .71 22.67 21.74 20.67

Biqram Trigram

7.20 5.49 8.58 7.90 4.07 9.43 5.31 5.86

10.15 3 . 6 1 5.60

14 .28 5.98 3.46 9.17

10.79 6.14 9 .15 9.56

10 .37 8.68 5.91 7.39 7 . 8 1 8.90 8.56 6.44 5.96

11 .40 1 1 . 2 6

4.32 11 .74

8.80 9.44 9.92

10 .13 10 .12

9.07 7.91

11.47

0.00 1 .49 1.18 1 .18 0.60 1.59 1.32 2.73 0.00 0.00 1.83 6 .08 0.00 0.00 1.34 3.30 0.00 0.00 0 .00 2.30 2.53 0.00 0 .00 2 . 3 1 1.18 0.70 0.00 1.56 1.97 2.42 0.00 3.47 3.72 0.00 0.00 2 .82 3.63 4.33 0.00 2.76

Word # of FKeq.

0.00 0.00 0 .00 0.00 0.00 0.00 0.00 0 .00 0.00 0.00 0.00 0.00 0.00 0 .a0 0 .00 0.00 0.00 0 .00 0.00 0 .00 0 .00 0.00 0 .00 0.00 0.00 0.00 0.00 0.00 0 .00 0.00 0.00 0 .00 0 .00 0 .00 0 .00 0.00 0.00 0.00 0.00 0.00

i K K .

2 3 3 2 3 4 3 2 2 4 2 1 3 3 2 2 3 2 3 3 2 3 3 2 2 3 2 2 2 2 4 2 2 2 3 2 2 3 2 3

1 4 8

IRREGULAR-LOW

CHAPTER 5

i c n t o a nmtaou rnwesa r b l e y a e b g n l o r t b e h a e b r g d i h r e a g c o b d e u l o fmsua e f n q r i e d n r g a g r h e t a e c l n q a r d l h y a e f l s t i e y r l w a e g n r l o emrtsa rmedno h r e t m o emnyla e n y r l a r t p e i m e p y l r a e r v t p o e r p l v u r n s e o a rn i ema e l s r t u h s r e d a l s e p m i n g l e s i d s e p r a d t s e r a e s r t m a t l e r a v i r l t s a e d t r n u

AC c %

6 2 55 6 5 6 7 6 9 7 2 5 8 6 8 7 3 6 2 7 1 6 7 7 7 6 5 5 3 6 6 6 7 6 7 6 6 7 1 6 9 7 3 7 8 67 7 0 7 1 66 6 3 6 9 7 1 7 5 6 9 6 5 8 2 7 7 7 4 67 7 0 7 1

RT R a t i n g msec

6 8 3 7 0 7 7 0 4 7 2 8 6 7 0 7 3 6 6 9 7 6 4 6 6 9 2 7 1 0 6 9 7 6 9 8 6 5 5 7 38 7 4 3 7 0 7 7 0 7 655 6 2 9 6 4 4 6 3 3 6 9 5 6 7 7 6 5 2 6 7 0 6 59 6 6 6 6 4 8 6 5 6 6 6 4 6 5 6 6 7 2 6 6 2 6 6 5 6 6 8 6 8 1 6 8 0 655 6 5 6

2.0 2.1 2.2 2.4 2.7 2.8 2.0 2.4 4.6 2.5 2.1 2.4 3.2 2.6 1.8 2.7 2.8 2.9 2.3 3.1 2.4 4.5 3.0 2.4 3.1 3.2 2.8 2.4 2.3 2.2 2.4 2.8 2.4 3.6 2.4 3.4 2.4 2.8 2.1

S i n g l e Le t t e r

20.38 19.06 20.26 18.96 19.04 19.78 18.09 20.49 19 .15 18.80 18.98 19.25 20.07 20.09 18.53 18.72 1 8 . 5 3 19 .24 20.19 19.48 19.84 19.05 20.20 20.65 19 .56 19.23 18.37 21.08 20.44 19.52 19.90 18.23 18 .25 19 .81 21.03 20.06 17.70 20.53 19.12

6.29 2.62 6.02 2.98 5.08 3.45 4.46 7.66 8.15 6.02 6.80

6.05 9 . 1 1 5.10 0.00 7.60 4.09 6 .11 4.25 3.88 5.25 4.15 8 .91 4.62 3.29 5.59 3.54 5.96 8.26 4.51 7.92 4.49 5.28 5.25

10.08 7.24 6.34 3.39 4.93

0.48 0.00 1.45 0.00 0.00 0.00 0.00 2.37 0.00 0.00 1.36

0 .00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 2.03 0.00 0.00 0.00 0.00 0.00 0.00 1 . 5 1 0.48 0.00 0.70 0.00 2.00 0.00

5.92 0.00 1.28 0.00 0.00

Word # o f F r e q .

0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0 .00 0.00 0.00 0.00

0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 c1.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

I r r .

3 4 3 2 4 3 3 2 1 3 3 4 2 2 4 2 4 4 4 3 3 2 2 2 2 2 2 4 2 4 3 3 2 2 3 4 2 4 3

APPENDIX 5.2 149

Append ix 5.2

S i n g l e - L e t t e r P o s i t i o n a l F r e q u e n c i e s (Token C o u n t s ) A c c o r d i n g t o S e r i a l P o s i t i o n and Word Leng th f o r Words

3 t o 7 L e t t e r s i n L e n g t h .

I n s t r u c t i o n s f o r Us ing F r e q u e n c y T a b l e s

The w o r d s u s e d t o o b t a i n t h e s i n g l e - l e t t e r f r e q u e n c i e s came from t h e Kuce ra and F r a n c i s ( 1 9 6 7 ) word c o u n t . Words which had a Kuce ra and F r a n c i s c o u n t o f a t l e a s t t h r e e and which a p p e a r e d i n a t l e a s t t h r e e d i f f e r e n t s ampled t e x t s were s e l e c t e d . They were t h e n s e p a r a t e d f o r e a c h word l e n g t h . T h e s e c o u n t s were m u l t i p l i e d b y t h e f r e q u e n c y o f e a c h o f t h e words s o t h a t t h e s i n g l e - l e t t e r f r e q u e n c i e s o f t h e t a b l e s a r e b a s e d on t o k e n r a t h e r t h a n t y p e c o u n t s ( see C h a p t e r 1 ) . T h i s s e l e c t i o n p r o c e d u r e y i e l d e d t h e f o l l o w i n g number of word t o k e n s f o r e a c h word l e n g t h : 210990, 153315 , 102699 , 76295, 68894 f o r 3 t h r o u g h 7 l e t t e r words , r e s p e c t i v e l y .

The number o f t imes e a c h l e t t e r o f t h e a l p h a b e t o c c u r r e d i n e a c h l e t t e r p o s i t i o n o f t h e words was c o u n t e d . T h e s e t o t a l s , a l o n g w i t h t h e i r s u m , a r e p r e s e n t e d i n t h e t a b l e s a s t h e f i r s t row o f numbers f o r e a c h l e t t e r . Thus , f o r e x a m p l e , f o r s i x - l e t t e r w o r d s , t h e l e t t e r 5 o c c u r r e d i n t h e s i x t h l e t t e r p o s i t i o n 231 t imes and o c c u r r e d i n a l l p o s i t i o n s a t o t a l o f 3 ,804 t imes . Below e a c h o f t h e f r e q u e n c i e s i s t h e b a s e 10 l o g a r i t h m o f t h e f r e q u e n c y c o u n t .

I t s h o u l d b e n o t e d t h a t f o r some s i n g l e l e t t e r s , t h e f r e q u e n c y o f o c c u r r e n c e is z e r o i n some p o s i t i o n s . The l o g a r i t h m o f z e r o is u n d e f i n e d , b u t f o r t h e p u r p o s e s o f t h e t a b l e s was s e t e q u a l t o z e r o .

150 C H A P T E R 5

S I N G L E L E T T E R F R E Q U E N C I E S F O R WORDS OF L E T T E R LENGTH 3

L E T T E R P O S I T I O N 1ST

A 39519 4.597

B 5902 3 .771

C 2466 3.392

D 2301 3 .362

E 760 2 .881

F 10988 4 .041

G 1967 3.294

H 21515 4 .333

I 2009 3 .303

J 515 2.712

K 182 2.260

L 1604 3 .205

M 4180 3 .621

2ND

28085 4 .448

3 .477

379 2.579

142 2 .152 11050 4 .043

644 2.809

498 2 .697 7 5 5 1 1 4.878 13084 4.117

0 0 .000

62 1 .792

3766 3.576

1 5 1 .176

3RD

2 2 1 2.344

364 2 . 5 6 1

1 8 6 2.270 37652 4 .576 82860 4.918

639 2 .806

790 2 .898

1 6 1 .204

7 . 845

0 0 .000

150 2.176

3192 3.504

3108 3 .492

SUM

67825 4 .831

6269 3.797

3 0 3 1 3.482 40095 4 .603 94670 4 .976 1 2 2 7 1 4 .089

3255 3 .513 97042 4.987 15100 4 .179

515 2.712

394 2 .595

8562 3 .933

7303 3.864

A P P E N D I X 5.2 151

S I N G L E L E T T E R F R E Q U E N C I E S FOR WORDS O F L E T T E R LENGTH 3

N

0

P

Q

R

s

T

U

V

W

X

Y

z

L E T T E R P O S I T I O N 1ST 2ND

7865 3.896 8900 3.949

1227 3.089

11 1.041

864 2.937 6354

3.803

73207 4.865

592 2.772

93 1.968

14079 4.149

0 0.000

3855 3.586

35 1.544

33973 4.531 23643 4.374

27 1.431

0 0.000

5591 3.747

736 2.867

1937 3.287

9472 3.976

41 1.613

2199 3.342

6 .778

126 2.100

0 0.000

3RD

6169 3.790 4829 3.684

474 2.676

0 0.000

16036 4.205 22017 4.343

16145 4.208

3307 3.519

73 1.863

5380 3.731

671 2.827

6704 3.825

0 0.000

SUM

48007 4.681 37372 4.573

1728 3.238

11 1.041

22491 4.352 29107 4.464

91289 4.960

13371 4.126

207 2.316

21658 4.336

677 2.831

111685 4.029

35 1.544

1 5 2 CHAPTER 5

SINGLE LETTER FREQUENCIES FOR WORDS OF LETTER LENGTH 4

LETTER POSITION 1ST

A 3077 3 .488

B 7266 3 .861

C 4530 3.656

D 4614 3 .664

E 3714 3.570

F 10556 4 . 0 2 3

G 3091 3 .490

H 9784 3 .991

I 2191 3 .341

J 2051 3 .312

K 2252 3 .353

L 7898 3 .898

M 10777 4 .032

2N D

26766 4 .428

244 2 .387

90 1 . 9 5 4

393 2.594 20802 4 .318

0 0 .000

1 2 8 2 .107 29988 4 .477 22145 4 .345

0 0 .000

8 5 1 . 9 2 9

2843 3 .454

50 1 .699

3RD

20259 4 .307

253 2 .403

6697 3 .826

2462 3 .391 21789 4 .338

1 6 4 8 3 .215

1 1 6 9 3 .068

376 2 . 5 7 5

9 6 6 1 3 .985

0 0 .000

3066 3 .487 1 1 2 2 5 4.050

6902 3 . 8 3 9

4TH

9 5 3 2 .979

301 2 .479

54 1 . 7 3 2 1 0 1 2 9 4 .006 32881 4 .517

528 2 .723

1 3 5 1 3 .131 1 2 3 2 2 4 .091

3 5 1 . 5 4 4

0 0 .000

5572 3 .746

7346 3 . 8 6 6

8373 3 . 9 2 3

SUM

51055 4 .708

8064 3 .907 1 1 3 7 1 4 .056 1 7 5 9 8 4 .245 79186 4 .899 1 2 7 2 4 4 .105

5739 3 .759 52470 4 .720 34032 4 .532

2051 3 .312 1 0 9 7 5 4.040 29312 4 .467 26102 4 .417

APPENDIX 5 .2


LETTER POSITION 1ST

N 2119 3 .326

0 4261 3 .630

P 3518 3 .546

Q 1 5 1 .176

R 3075 3 .488

S 1 0 8 1 5 4.034

T 30636 4 .486

U 1340 3 .127

V 1308 3 .117

W 22367 4.350

X 0 0 .000

Y 1996 3 .300

2 64 1 . 8 0 6

2N D

5 7 5 3 3.760 24056 4 .381

978 2 .990

0 0 .000

6514 3 .814

742 2.870

563 2 . 7 5 1

7042 3 .848

2843 3.454

555 2 .744

62 1 . 7 9 2

673 2.828

0 0 .000

3RD

8 2 6 5 3 .917 10798 4 .033

1040 3 .017

0 0 .000 13598 4 .133 1 0 0 9 1 4 .004 1 2 2 5 1 4 .088

2751 3 .439

5723 3 .758

1 5 2 6 3 .184

470 2.672

998 2.999

305 2.484

4TH

1 4 2 5 6 4 .154

3158 3 .499

1 7 1 5 3 .234

3 . 477 5335

3 .727 11497 4 .061 24894 4 .396

38 1 . 5 8 0

0 0 .000

2163 3 . 3 3 5

7 7 1 . 8 8 6 1 0 2 1 4 4 .009

1 2 0 2 .079

SUM

30393 4 .483 42273 4 . 6 2 6

7 2 5 1 3 .860

1 8 1 . 2 5 5 28522 4 .455 33145 4 .520 68344 4 .835 1 1 1 7 1 4 .048

9874 3 .994 2661 1 4 . 4 2 5

6 0 9 2 . 7 8 5 1 3 8 8 1 4 .142

489 2 .689

1 5 3

1 5 4 CHAPTER 5


LETTER POSITION

A

B

C

D

E

F

G

H

I

J

K

L

1ST

7359 3 .867

5264 3 .721

6416 3 .807

2379 3 .376

2189 3 .340

5614 3 .749

3565 3 .552

3348 3 .525

917 2 .962

525 2.720

618 2 .791

4187 3 .622

2ND

1 0 4 5 5 4 .019

2151 3 . 3 3 3

556 2 .745

6 2 5 2 .796

9 7 0 9 3 .987

1 5 1 8 3 .181

700 2 .845 1 8 8 0 8 4 .274

9 8 2 1 3 .992

0 0 .000

8 5 1 . 9 2 9

4783 3 .680

M 4220 1 3 5 7 3 .625 3 . 1 3 3 3 .323

3RD

1 2 3 0 6 4 .090

8 2 6 2 .917

9 3 8 2 .972

2681 3 .428 1484 5 4 .172

3 14 2 .497

3796 3 .579

1 7 4 0 3 .241 13572 4 .133

2 9 1 2 .464

1 1 8 2 3 .073

2801 3 .447

2103

4TH

5563 3 .745

4 38 2 .641

8 3 3 2 3 .921

2860 3 . 4 5 6 18479 4 .267

447 2 .650

1 4 7 5 3 . 1 6 9

2465 3.392

683 2 3 .835

0 0 .000

1 2 4 2 3 .094 1 1 7 0 8 4 .068

1 6 4 1 3 .215

5TH

5 2 3 2 .719

3 6 1 . 5 5 6

582 2 .765 1 1 8 4 5 4.074 21152 4 .325

493 2 .693

3349 3 .525

7039 3 .848

7 5 1 . 8 7 5

0 0 .000

2195 3 .341

4948 3 .694

404 2 .606

SUM

36206 4 .559

8 7 1 5 3 .940 1 6 8 2 4 4 .226 20390 4 .309 66374 4 .822

8386 3 .924 1 2 8 8 5 4 .110 33400 4.524 31217 4 .494

8 1 6 2 .912

5322 3 .726 28427 4 .454

9 7 2 5 3 . 9 8 8



LETTER POSITION 1ST

N 2336 3 .368

0 3064 3 .486

P 4418 3 .645

Q 515 2 .712

R 3036 3 .482

S 11526 4 .062

T 1 4 0 4 3 4 . 1 4 7

U 2038 3 .309

V 938 2 .972

W 12634 4 .102

X 0 0 .000

Y 1547 3 .189

2 3 .477

2ND

2899 3 .462 18464 4 .266

1255 3 .099

1 1 5 2 . 0 6 1

7818

959 2 .982

5756 3 .760

3058 3 .485

687 2 .837

682 2 .834

1 5 1 2.179

287 2 .458

0 0 .000

3 .893

3RD

4331 3 .637 1 0 6 1 2 4 .026

1 0 4 6 3 .020

0 0 .000

8 5 2 3 3 .931

2106 3 .323

4727 3 .675

9278 3 .967

2979 3 .474

755 2.878

364 2 . 5 6 1

4 57 2 .660

1 2 6 2 .100

4TH

8 5 1 3 3 .930

2682 3 .428

8 7 9 2 .944

0 0 .000

9276 3 .967

8 1 0 8 3 .909

6054 3 .782

3139 3 . 4 9 7

1 2 3 9 3 .093

1 1 2 1 3 .050

7 . 845

1 0 2 2 .009

9 7 1 . 9 8 7

5TH

5318 3 .726

4 8 1 2 .682

7 4 7 2 .873

0 0 .000 1 1 7 9 1 4 .072 15072 4 .178 1 1 0 9 8 4 . 0 4 5

8 .90 3

9 . 954

395 2 .597

1 5 9 2 . 2 0 1

4977 3 .697

3 .477

SUM

23397 4.369 35303 4 .548

8 3 4 5 3 .921

6 30 2.799 40444 4 .607 37771 4 * 577 41678 4 .620 1 7 5 2 1 4.244

5852 3.767 15587 4 .193

681 2 .833

7370 3.867

229 2.360

1 5 6 CHAPTER 5


LETTER POSITION 1ST

A 5 5 2 9 3 . 7 4 3

B 5 1 1 6 3 .709

C 6 2 3 7 3 . 7 9 5

D 3 1 4 6 3 . 4 9 8

E 3 3 1 3 3 .520

F 3 9 5 3 3 * 597

G 1 7 1 2 3 . 2 3 4

H 2310 3 .364

I 1 6 6 8 3 . 2 2 2

J 5 4 1 2 . 7 3 3

K 2 2 5 2 .352

L 3918 3 . 5 9 3

M 4718 3 . 6 7 4

2ND

1 1 0 5 7 4 .044

284 2 . 4 5 3

1 7 5 3 3 .244

294 2 .468 1 4 3 0 8 4 . 1 5 6

90 3 2 .956

2 1 1 2 . 3 2 4

4 4 9 8 3 . 6 5 3

7 3 9 6 3 .869

0 0 .000

7 3 1 . 8 6 3

3 0 2 8 3 . 4 8 1

5 4 8 2 . 7 3 9

3RD

6 0 8 1 3 .784

1 1 0 2 3 . 0 4 2

3 7 6 5 3 .576

1 6 4 8 3 . 2 1 7

3 5 4 8 3 .550

2424 3 . 3 8 5

1 7 4 6 3 . 2 4 2

1 2 9 2 3 . 1 1 1

4374 3 . 6 4 1

1 4 0 2 . 1 4 6

7 3 2 2 . 8 5 5

4 4 1 7 3 . 6 4 5

3 9 1 2 3 . 5 9 2

4TH

4 2 2 6 3 .626

1 2 8 6 3 . 1 0 9

1 4 9 4 3 . 1 7 4

2 6 3 8 3 . 4 2 1

7 6 1 9 3 . 8 8 2

347 2 .540

2500 3 .398

2784 3 . 4 4 5 1 0 6 7 6 4 . 8 2 8

0 0 .000

2 0 0 2 3 . 3 0 1

3 4 4 8 3 .538

2 1 4 3 3 . 3 3 1

5TH

3 2 5 7 3 . 5 1 3

7 9 1 . 8 9 8

3384 3 . 5 2 9

1 2 8 4 3 . 1 0 9 2 3 1 1 1 4 .364

5 7 1 . 7 5 6

2 4 2 5 3 . 3 8 5

1 0 9 6 3 . 0 4 0

2 9 0 9 3 . 4 6 4

B 0 . 0 0 0

5 4 1 2 . 7 3 3

8 7 2 1 3 . 9 4 1

1 2 9 7 3 . 1 1 3

6TH

4 4 9 2 . 6 5 2

4 0 1 . 6 0 2

7 4 3 2 . 8 7 1 1 3 4 7 3 4 . 1 2 9 1 2 4 7 1 4 . 0 9 6

5 9 3 2 . 7 7 3

3784 3 . 5 7 8

2 5 3 1 3 . 4 0 3

4 5 1 . 6 5 3

0 0 . 0 0 0

2 3 1 2 .364

2 7 7 1 3 . 4 4 3

9 8 0 2 . 9 9 1

SUM

3 0 5 9 9 4 .486

7 9 0 7 3 . 8 9 8 1 7 3 7 6 4 .240 2 2 4 8 3 4 . 3 5 2 6 4 3 7 0 4 .809

8 2 7 7 3 . 9 1 8 1 2 3 7 8 4 . 0 9 3 1 4 5 1 1 4 . 1 6 2 2 7 0 6 8 4 . 4 3 2

6 8 1 2 . 8 3 3

3804 3 . 5 8 0 2 6 3 0 3 4 .420 1 3 5 9 8 4 . 1 3 3

APPENDIX 5 .2 1 5 7


LETTER POSITION 1ST

N 2043 3 .310

0 1398 3 .146

P 5827 3 .765

Q 70 1 . 8 4 5

R 4276 3 . 6 3 1

S 1 1 4 2 3 4 .058

T 3929 3 .594

U 1079 3 .033

V 1 0 7 3 3 . 0 3 1

W 2645 3 .422

X 0 0 .000

Y 140 2 .146

z 6 .778

2ND

3306 3 .519 10986 4.041

1154 3.062

1 6 6 2 .220

4923 3.692

862 2 .936

3427 3 .535

5252 3.720

1 8 3 2.262

308 2 .489

710 2 .851

665 2 .823

0 0 .000

3RD

4535 3 .657

6 7 1 5 3.827

1 3 9 8 3 .146

9 1 1 .959

9119 3.960

4710 3 .673

7 5 3 1 3 .877

2800 3 .447

1 6 0 6 3 .206

1 3 8 2 3 . 1 4 1

1 5 4 2 .188

999 3.000

74 1 .869

4TH

4451 3 .648

5 9 2 5 3 .773

2401 3 .380

6 4 1 . 8 0 6

3680 3 .566

2784 3 .445

7658 3 .884

5928 3 .773

984 2 .993

772 2 .888

1 3 1 .114

3 50 2 .544

1 2 2 2 .086

5TH

8 0 0 5 3 . 9 0 3

5 2 2 1 3 .718

786 2 .895

0 0 .000

6 1 8 8 3 . 7 9 2

2717 3 .434

3149 3 .498

1 0 2 7 3 .012

364 2 .561

1 1 0 2 . 0 4 1

3 . 477 4 94

2 .694 70

1 . 8 4 5

6TH

5286 3 .723

172 2 .236

1 0 9 2 .037

0 0 .000

8147 3 . 9 1 1 1 0 9 0 4 4 .038

6979 3 .844

6 1 1 . 7 8 5

0 0 .000

670 2 .826

3 1 1 . 4 9 1

5 8 2 5 3 .765

0 0 .000

S U M

27626 4 . 4 4 1 30417 4 .483 1 1 6 7 5 4 .067

391 2 .592 3 6 3 3 3 4 .560 33400 4 . 5 2 4 32673 4 .514 16147 4 .208

4210 3 .624

5887 3 .770

9 1 1 2 .960

8 4 7 3 3 .928

272 2 .435

158 CHAPTER 5


LETTER POSITION 1ST

A 4796 3 . 6 8 1

B 4147 3 .618

C 7268 3 .861

D 2846 3 .454

E 3068 3 .487

F 3548 3.550

G 1982 3 .297

H 3232 3 .509

I 1268 3 .103

J 471 2 .673

K 532 2 .726

L 1990 3 .299

M 3649 3 .562

2ND

6979 3 .844

407 2.610

946 2 .976

372 2 .571 1 5 6 5 5 4 .195

6 2 3 2 .794

663 2 .822

3963 3 .598

6 5 7 1 3 .818

0 0 .000

48 1 . 6 8 1

2524 3 .402

9 1 7 2 .962

3RD

7 3 5 3 3.866

690 2.839

3977 3.600

1 1 6 8 3 .067

4768 3 .678

1 1 6 2 3 . 0 6 5

1 4 9 3 3 .174

5 0 1 2 .700

4053 3 .608

1 6 7 2 .223

69 1 .839

3526 3 .547

2 9 2 3 3 .466

4TH

4582 3 .661

1 3 5 7 3 .133

2 9 2 1 3 .466

2263 3 .355

6532 3 . 8 1 5

8 5 9 2 .934

1564 3 .194

2243 3 .351

6 0 3 1 3 .780

2 54 2 .405

1280 3 .107

4545 3 .658

1730 3 .238

5TH

5253 3.720

6 1 1 2.786

1 7 3 5 3 .239

1 2 0 2 3.080 1 0 0 7 3 4 .003

4 58 2 .661

1 8 0 3 3 .256

2874 3 .458 1 5 1 1 5 4 .179

0 0 .000

524 2 .719

3125 3 .495

983 2 .993

6TH

5036 3.702

8 5 1 .929

2707 3.432

2059 3.314 1 6 8 3 5 4 .226

1 3 2 2 .121

2323 3 . 3 6 6

1 0 3 5 3 . 0 1 5

1 7 3 5 3 .239

0 0 .000

1 3 7 2 .137

4 4 3 3 3 .647

656 2 .817

7TH

567 2.754

1 9 1 . 2 7 9

3 55 2 .550

8884 3 .949

9106 3 .959

769 2.886

7 2 1 5 3 .858

1 6 4 4 3 .216

1 8 1 . 2 5 5

0 0 .000

1 2 0 2 .079

3830 3 .583

1 4 7 8 3 .170 4 .091

SUM

34566 4 .539

7316 3 .864 1 9 9 0 9 4 .299 18794 4 .274 66037 4 . 8 2 0

7 5 5 1 3 .878 1 7 0 4 3 4 .232 15492 4.190 34791 4 . 5 4 1

8 9 2 2 .950

2710 3 .433 23973 4 .380 1 2 3 3 6

APPENDIX 5 .2


LETTER POSITION 1ST

N 1 6 2 8 3 .212

0 1460 3 .164

3 .783 Q 358

2 .554 R 3726

3 .571 S 8092

3 .908 T 3 7 3 1

3 .572 U 603

2 .780 V 1 0 4 3

3 .018 W 3289

3 .517 X 0

0 .000 Y 9 3

1 .968 2 7

.845

e 6067

2N D

3150 3 .498

8667 3 .938

1 2 1 1 3 . 0 8 3

1 1 3 2 .053

6 9 9 1 3 .845

558 2 .747

1976 3 .296

4693 3 .671

386 2 .587

1 6 1 2 .207

954 2 .980

366 2 . 5 6 3

0 0 .000

3RD

5166 3 . 7 1 3

5792 3 . 7 6 3

2154 3 .333

1 9 9 2.299

8487 3 .929

4162 3 .619

5538 3 . 7 4 3

2573 3.410

1 4 2 1 3 . 1 5 3

764 2 .883

314 2.497

392 2 .593

8 2 1 .914

4TH

3785 3 .578

2962 3 .472

2655 3 .424

26 1 .415

4046 3 .607

4055 3 .608

8 7 5 5 3.942

3082 3 .489

1 4 4 2 3 .159

1544 3 .189

0 0 .000

304 2 .483

77 1 .886

5TH 6TH

3401 1 1 6 2 3 3 . 5 3 2 4 . 0 6 5

5046 2700 3 .703 3 .431

994 576 2 .997 2 .760

2 3 0 1 . 3 6 2 0 .000

4 7 9 1 6193 3 .680 3 .792

1 2 2 4 4 2 3 3 3 .088 3 .627

4 2 1 5 3466 3 .625 3 .540

3862 1840 3 .587 3 .265

1 1 0 6 6 2 9 3 .044 2 .799

269 2 54 2 .430 2 .405

3 1 38 1 . 4 9 1 1 . 5 8 0

1 1 6 66 2 .064 1 .820

6 0 1 0 3 1 .778 2 .013

7TH

4650 3 .667

210 2 .322

1 3 8 2 .140

0 0 .000

4948 3 .694 1 2 0 5 4 4 .081

6324 3 .801

3 .477

0 0 .000

1 1 6 2 .064

1 1 4 2 .057

6 3 3 2 3 . 8 0 2

0 0 .000

1 5 9

SUM

3 3 4 0 3 4 .524 26837 4 .429 1 3 7 9 5 4 .140

719 2 .857 39182 4 .593 34378 4 .536 34005 4 .532 1 6 6 5 6 4 .222

6027 3 .780

6397 3 . 8 0 6

1 4 5 1 3 .162

7669 3 .885

329 2 .517

160 CHAPTER 5

Appendix 5 . 3

Bigram P o s i t i o n a l F r e q u e n c i e s (Token C o u n t s ) Accord ing t o S e r i a l P o s i t i o n and Word L e n g t h f o r Words

3 t o 7 L e t t e r s i n L e n g t h .

I n s t r u c t i o n s f o r u s i n g f r e q u e n c y t a b l e s

T h e s e c o u n t s were b a s e d on t h e same word t o k e n s a s were t h e s i n g l e - l e t t e r c o u n t s i n Appendix 5 . 2 . I n t h i s c a s e , however , e a c h word was b r o k e n down i n t o i t s b ig ram componen t s ( i . e . , b a t t l e - - - - > &, at, E, g , k) and t h e f r e q u e n c y o f o c c u r r e n c e o f e a c h o f t h e b i g r a m s was t a b u l a t e d f o r e a c h word l e n g t h . Fo r example , f o r s i x - l e t t e r w o r d s , t h e b i g r a m 9 o c c u r r e d a s t h e i n i t i a l b ig ram 1 8 5 t imes, a s t h e s e c o n d b ig ram 160 t imes, a s t h e t h i r d b i g r a m 1 4 8 t imes , e t c . N o t i c e t h a t 3 n e v e r o c c u r r e d a s t h e s i x t h b ig ram. A l s o n o t i c e t h a t t h e b ig ram do n e v e r o c c u r r e d a t a l l . A b i g r a m which d i d n o t o c c u r a t l e a s t o n c e f o r words o f a g i v e n l e n g t h was o m i t t e d from t h e l i s t i n g i n t h e t a b l e s .

I t s h o u l d b e n o t e d t h a t f o r some b i g r a m s , t h e f r e q u e n c y o f o c c u r r e n c e is z e r o i n some p o s i t i o n s . The l o g a r i t h m o f z e r o i s u n d e f i n e d , b u t f o r t h e p u r p o s e s o f t h e t a b l e s was se t e q u a l t o z e r o .

APPENDIX 5.2 1 6 1

BIGRAM FREQUENCIES FOR WORDS OF LETTER LENGTH 3

BIGRAM POSITION 1ST

AB 3 .477

AC 298 2.474

AD 9 8 1 .991

AF 5 .699

AG 473 2.675

A1 424 2.627

AK 0 0.000

AL 3008 3.478

AM 1 5 1.176

AN 3 0 2 3 2 4.480

A 0 0 0 .000

AP 1 8 1 . 2 5 5

AR 4736 3 .675

AS 1 4 4 2.158

A T 1 6 1 . 2 0 4

AU 25 1 . 3 9 8

AV 1 3 1 . 1 1 4

AW 5 .699

AX 6 .778

AY B 0.000

BA 348

2ND

1 2 1 .079

0 0 .000

5378 3 . 7 3 1

0 0 .000

7 5 1 . 8 7 5

0 0 .000

1 5 1 .176

3 3 1 .519

1 2 2 2 .086

3316 3 .521

24 1 . 3 8 0

9 8 1 . 9 9 1

1 3 2 4 3 .122

1 2 3 6 4 4 .092

414 2 .617

0 0 . 0 0 0

0 0 . 0 0 0

7 1 3 2.853

226 2 .354

3 9 7 1 3 .599

' 0 2 .542 0 .000

SUM

1 5 1.176

298 2.474

5476 3.738

5 .699

548 2.739

424 2.627

1 5 1.176

3 0 4 1 3.483

1 3 7 2.137

33548 4.526

24 1.380

1 1 6 2.064

6 0 6 0 3.782

1 2 5 0 8 4.097

4 30 2.633

2 5 1 .398

1 3 1 .114

7 1 8 2.856

2 3 2 2.365

3 9 7 1 3.599

348 2.542

1 6 2 CHAPTER 5


BIGRAM POSITION 1ST

BE 1 9 4 2 . 2 8 8

BI 492 2 . 6 9 2

BO 367 2 . 5 6 5

BU 4 5 0 1 3 . 6 5 3

C A 2108 3 .324

CE 0 0 .000

co 7 3 1 . 8 6 3

C R 48 1 . 6 8 1

CT 0 0 .000

CU 237 2 . 3 7 5

CY 0

DA 7 4 0 2 .869

DD 0 0 .000

DE 44 1 . 6 4 3

D I 1 1 5 2 3 . 0 6 1

DO 1 3 5 2 .130

DR 7 3 1 . 8 6 3

DS 0 0 . 0 0 0

DU 1 5 7 2 .196

EA 9 0 1 . 9 5 4

E B 0 0 .000

0 . 0 0 0

2 N D

3 . h77 0

0 . 0 0 0 0

0 .000 0

0 .000 0

0 . 0 0 0 6 0

1 . 7 7 8 0

0 . 0 0 0 0

0 . 0 0 0 307

2 .487 0

0 . 0 0 0 1 2

1 . 0 7 9 0

0 .000 1 3 2

2 . 1 2 1 0

0 . 0 0 0 0

0 . 0 0 0 0

0 .000 0

0 . 0 0 0 1 0

1 . 0 0 0 0

0 . 0 0 0 1 2 6

2 . 1 0 0 26

1 . 4 1 5

SUM

1 9 7 2 .294

492 2 .692

367 2 . 5 6 5

4 5 0 1 3 . 6 5 3

2 1 0 8 3 . 3 2 4

6 0 1 . 7 7 8

1 3 1 . 8 6 3

4 8 1 . 6 8 1

3 07 2 . 4 8 7

2 37 2 . 3 7 5

1 2 1 . 0 7 9

7 4 0 2 .869

1 3 2 2 . 1 2 1

4 4 1 . 6 4 3

1 1 5 2 3 . 0 6 1

1 3 5 2 .130

7 3 1 . 8 6 3

1 0 1 . 0 0 0

1 5 7 2 .196

2 1 6 2 .334

2 6 1 . 4 1 5

A P P E N D I X 5.2 1 6 3

B I G R A M F R E Q U E N C I E S F O R WORDS O F L E T T E R LENGTH 3

B I G R A M P O S I T I O N 1 S T

EC 0 0 .000

E D 0 0.000

E E 0 0.000

EG 25 1.398

E I 0 0.000

E L 3 .477

EM 0 0 .000

EN 410 2 .613

E O 0 0.000

E P 0 0.000

E R 30 1 . 4 7 7

E S 3 . 4 7 1

E T 58 1.763

EV 1 9 1.279

EW 0 0.000

EX 0 0.000

EY 1 2 2 2.086

FA 505 2.703

F E 679 2.832

FF 0 0.000

F I 1 6 1 2.207

2 N D

3 6 1.556

513 2.710

8 4 5 2.927

69 1 . 8 3 9

7 .845

1 6 1 . 2 0 4

8 ,903

1 0 8 3 3 .035

7 .845

1 3 1.114

3408 3 .532

1 5 5 2.190

2243 3 . 3 5 1

3 3 1 . 5 1 9

2262 3.354

9 7 1 . 9 8 7

1 0 3 2 .013

0 0 .000

0 0 . 0 0 0

6 3 9 2.805

0 0.000

SUM

3 6 1.556

513 2.710

8 4 5 2.927

9 4 1.973

7 .845

1 9 1 . 2 7 9

8 .903

1 4 9 3 3.174

7 .845

1 3 1.114

3438 3.536

1 5 8 2.199

2 3 0 1 3 .362

5 2 1 .716

2262 3 .354

9 7 1 . 9 8 1

225 2.352

505 2.703

679 2.832

6 3 9 2.806

1 6 1 2.207

1 6 4 C H A P T E R 5

B I G R A M F R E Q U E N C I E S F O R WORDS O F L E T T E R L E N G T H 3

B I G R A M P O S I T I O N 1ST

FL 5 1 1.708

FO 9 5 3 5 3.979

FT 0 0.000

FU 57 1.756

G A 1 5 4 2.188

G E 7 8 1 2.893

GG 0 0.000

G I 27 1 . 4 3 1

GO 8 1 9 2.913

GU 1 8 6 2 .270

HA 7 6 9 4 3.886

HE 3078 3.488

H I 9 7 4 7 3.989

HO 9 7 0 2.987

HU 26 1 .415

H Y 0 0.000

I A 0 0.000

I C 57 1 . 7 5 6

I D 0 0.000

I E 0 0 .000

I G 0 0.000

2ND

0 0.000

0 0.000

5 .699

0 0.000

0 0.000

2 27 2.356

1 2 1 . 0 7 9

0 0.000

259 2.413

0 0.000

0 0.000

7 2 8 3 0 4 .862

0 0.000

2252 3.353

0 0.000

429 2.632

48 1 .681

8 .903

1 3 0 1 3.114

1 6 9 2.228

455 2.658

SUM

5 1 1.708

9 5 3 5 3.979

5 .699

5 7 1 .756

1 5 4 2.188

1 0 0 8 3.003

1 2 1 .079

27 1 . 4 3 1

1 0 7 8 3.033

1 8 6 2.270

7 6 9 4 3.886

7 5 9 0 8 4 .880

9 7 4 7 3.989

3 2 2 2 3.508

26 1 .415

4 29 2.632

4 8 1 .681

6 5 1.813

1 3 0 1 3.114

1 6 9 2 .228

455 2.658

APPENDIX 5.2 1 6 5


BIGRAM POSITION 1ST

IK 4 .602

IL 39 1 . 5 9 1

IM 0 0.000

IN 36 1 . 5 5 6

I 0 6 .778

IP 0 0 .000

IR 0 0.000

IS 0 0.000

IT 1858 3 .269

IV 9 .954

IX 0 0.000

J A 77 1.886

J E 63 1 . 7 9 9

JI 36 1 . 5 5 6

J O 3 3 3 2 .522

JU 6 .778

KA 2 1 1.322

KE 1 0 0 2 .000

KI 6 1 1 .785

KY 0 0 .000

LA 4 9 1 2 .691

2ND

0 0.000

9 3 1 .968

2 7 4 1 3 .438

1 6 8 2 .225

4 .602

88 1 . 9 4 4

352 2,547

6997 3.845

413 2.616

0 0 .000

247 2.393

0 0.000

0 0.000

0 0.000

0 0.000

0 0 .000

0 0 .000

4 .602

0 0 .000

58 1 . 7 6 3

1 7 1.230

SUM

4 .602

1 3 2 2 . 1 2 1

2 7 4 1 3.438

204 2.310

1 0 1 . 0 0 0

8 8 1 .944

352 2.547

6997 3 .845

2 2 7 1 3.356

9 .954

247 2.393

7 7 1 .886

63 1 .799

36 1 .556

333 2.522

6 .778

2 1 1.322

1 fl4 2.017

6 1 1 .785

58 1.763

508 2.706

1 6 6 C H A P T E R 5

BIGRAM F R E Q U E N C I E S F O R WORDS OF L E T T E R LENGTH 3

B I G R A M P O S I T I O N 1ST

LD 0 0.000

L E 6 1 8 2 .791

L I 1 1 3 2.053

L L 0 0 .000

LM 0 0.000

L O 377 2 .576

L T 5 .699

LU 0 0.000

L Y 0 0.000

MA 2690 3.430

ME 8 9 5 2.952

M I 1 3 1.114

MO 1 6 1 .204

MR 534 2.728

MU 3 2 1 .505

MY 0 0.000

NA 1 7 1 .230,

NC 0 0.000

ND 0 0 .000

N E 1 6 6 9 3.222

N I 3 ,477

2 N D

6 6 0 2.820

0 0.000

0 0.000

3040 3 .483

3 . 4 1 1

0 0.000

0 0 .000

8 .903

3 8 1.580

0 0.000

0 0.000

0 0.000

0 0.000

0 0.000

0 0.000

1 5 1 .176

0 0.000

20 1 . 3 0 1

29265 4.466

3 2 9 2 3.517

0 0.000

SUM

6 6 0 2.820

6 1 8 2 .791

1 1 3 2.053

3040 3.483

3 .417

377 2.576

5 .699

8 .903

3 8 1 . 5 8 0

2690 3 .430

8 9 5 2.952

1 3 1 . 1 1 4

1 6 1.204

534 2.728

32 1 .505

1 5 1 . 1 7 6

1 7 1 . 2 3 0

20 1 . 3 0 1

2 9 2 6 5 4.466

4 9 6 1 3.696

3 .477

APPENDIX 5.2 1 6 7


BIGRAM POSITION 1ST

NK 0 0.000

NN 0 0.000

NO 6 1 6 1 3.790

NT 0 0 .000

NU 1 5 1 . 1 7 6

NY 0 0.000

OA 1 5 1 . 1 7 6

OB 0 0 .000

oc 24 1 .380

OD 44 1 . 6 4 3

OE 0 0.000

OF 6 3 9 2 .806

OG 0 0 . 0 0 0

01 93 1 .968

OL 6 6 0 2 .820

OM 0 0 . 0 0 0

ON 3292 3 . 5 1 7

00 0 0 . 0 0 0

OP 0 0 .000

OR 3 .477

0s 0 0 .000

2ND

7 . 8 4 5

38 1 . 5 8 0

0 0.000

6 .778

0 0 .000

1 3 4 5 3 .129

0 0.000

307 2.487

2 3 1 .362

3 57 2 .553

8 1 1.908

0 0 . 0 0 0

1 1 4 2.057

0 0.000

1 0 1.000

6 6 1 .820

3 0 6 2 .486

2 .926

230 2 .362

9 6 8 4 3.986

5 2 1 . 7 1 6

a 4 4

SUM

7 .845

3 8 1 . 5 8 0

6 1 6 1 3.790

6 .778

1 5 1 . 1 7 6

1 3 4 5 3.129

1 5 1 . 1 7 6

3 07 2 .487

47 1 . 6 7 2

4 0 1 2 .603

8 1 1 . 9 0 8

639 2.806

1 1 4 2.057

93 1.968

6 7 0

6 6

3 5 9 8 3.556

8 4 4 2 .926

230 2 .362

9 6 8 7 3 .986

52 1 . 7 1 6

2.826

1 . 8 2 0

1 6 8 CHAPTER 5


BIGRAM POSITION 1ST

OT 0 0.000

ou 3348 3.525

ov 0 0 .000

OW 7 8 2 2.893

ox 0 0 .000

OY 0 0.000

PA 253 2.403

PE 400 2 .602

PI 7 5 1 .875

PO 40 1 . 6 0 2

PR 22 1 . 3 4 2

PT 0 0.000

PU 437 2 .640

PY 0 0.000

QU 11 1 . 0 4 1

RA 2 1 2 2.326

RC 0 0.000

RE 248 2.394

RI 3 9 1 . 5 9 1

RM 0 0.000

RO 1 2 1 2.083

2 N D

5397 3.732

3 2 9 9 3.518

40 1 .602

2405 3 .381

1 0 1 2.004

327 2.515

0 0 .000

3 .477

0 0 .000

0 0.000

0 0.000

1 5 1 .176

0 0.000

9 . 9 5 4

0 0.000

30 1.477

4 1 1 . 6 1 3

4 3 9 6 3.643

0 0 .000

9 4 1.973

1 6 1.204

SUM

5 3 9 7 3.732

6 6 4 7 3 .823

4 0 1 .602

3187 3.503

1 0 1 2 .004

3 27 2.515

253 2.403

403 2.605

7 5 1 .875

40 1.602

2 2 1 . 3 4 2

1 5 1 .176

437 2.640

9 . 9 5 4

11 1 . 0 4 1

2 4 2 2.384

4 1 1 . 6 1 3

4644 3.667

3 9 1 . 5 9 1

9 4 1.973

1 3 7 2.137

APPENDIX 5.2 1 6 9


BIGRAM POSITION 1ST

RS 0 0 .000

RT 0 0 .000

RU 240 2.380

RY 4 .602

S A 1 1 9 4 3.077

SE 1 4 1 4 3.150

3 .458

SI 439 2.642

SK 58 1 . 7 6 3

SL 5 .699

SO 1 8 5 2.267

SP 9 .954

ss 0 0.000

ST 0 0.000

SU 1 7 8 2 .250

TA 2 4 1 2.382

TC 0 0.000

TD 0 0 .000

TE 208 2.318

TH 69983 4 .845

TI 8 2 1 . 9 1 4

sn 2872

2N D

5 3 9 2.732

208 2.318

0 0.000

267 2.427

0 0.000

589 2.770

11 1 . 0 4 1

0 0.000

1 2 8 2.107

0 0.000

0 0.000

0 0 .000

5 .699

3 .477

0 0.000

0 0.000

5 8 1.763

5 .699

1 6 1.204

0 0.000

0 0 .000

SUM

5 39 2.732

208 2.318

240 2.380

2 7 1 2.433

1194 3.077

2003 3 .302

2883 3.460

439 2.642

1 8 6 2.270

5 .699

1 8 5 2.267

9 - 9 5 4

5 .699

3 .477

1 7 8 2.250

2 4 1 2.382

5 8 1 . 7 6 3

5 .699

224 2.350 6 9 9 8 3 4.845

8 2 1 .914

170 C H A P T E R 5

BIGRAM F R E Q U E N C I E S F O R WORDS O F L E T T E R LENGTH 3

BIGRAM P O S I T I O N 1ST

TO 1125 3.051

TR 140 2.146

TS 0 0.000

TU 16 1.204

TW 1412 3.150

UB 0 0.000

UD 0 0.000

UE 0 0.000

UG 0 0.000

UH 0 0.000

U M 0 0.000

UN 3 .477

uo 0 0.000

UP 0 0.000

UR 0 0.000

U S 589 2.770

U T 0 0.000

UY 0 0 * 000

VA 32 1.505

VE 0 0.000

V I 52 1.716

2N D

0 0.000

0 0.000 1858

3.269 0

0.000 0

0.000 19

1.279 41

1.613 166

2.220 65

1.813 5

,699 74

1.869 486

2.687 11

1.041 45

1.653 1268 103 37

568 134 853 121 083

0 0.000

32 1.505

0 0.000

S U M

1125 3.051

140 2.146 1858

3.269 16

1.204 1412

3.150 19

1.279 41

1.613 166

2.220 65

1.813 5

.699 74

1.869 489

2.689 11

1.041 45

1.653 1268

3.103 626

2.797 7134

3.853 121

2.083 32

1.505 32

1.505 52

1.716

APPENDIX 5.2 1 7 1


BIGRAM POSITION 1ST

vo 9 . 9 5 4

VY 0 0 . 0 0 0

WA 1 1 2 0 3 4 . 0 4 9

WE 6 4 1 . 8 0 6

WH 2 6 5 6 3 . 4 2 4

WI 7 5 1 . 8 7 5

WN 0 0 . 0 0 0

wo 7 6 1 . 8 8 1

W R 5 . 6 9 9

XE 0 0 . 0 0 0

YE 5 6 9 2 . 7 5 5

YO 3 2 8 6 3 . 5 1 7

ZE 2 6 1 . 4 1 5

zo 9 . 9 5 4

2 N D

0 0 . 0 0 0

9 . 9 5 4

0 0 . 0 0 0

1 5 1 . 1 7 6

0 0 . 0 0 0

0 0 . 0 0 0

7 7 2 2 .888

1 4 1 2 3 .150

0 0 . 0 0 0

6 . 7 7 8

1 2 6 2 . 1 0 0

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

SUM

9 . 9 5 4

9 . 9 5 4

1 1 2 0 3 4 . 0 4 9

7 9 1 . 8 9 8

2 6 5 6 3 .424

7 5 1 . 8 7 5

7 7 2 2 . 8 8 8

1 4 8 8 3 . 1 7 3

5 . 6 9 9

6 . 7 7 8

6 9 5 2 . 8 4 2

3 2 8 6 3 .517

2 6 1 . 4 1 5

9 . 9 5 4

172 CHAPTER 5


BIGRAM POSITION 1ST

AB 236 2.373

AC 65 1.813

AD 54 1.732

AF 0 0.000

AG 69 1.839

AH 0 0.000

A1 62 1.792

AK 10 1.000

AL 1127 3.052

AM 33 1.519

AN 98 1.991

A0 0 0.000

AP 4 .602

AQ 0 0.000

AR 660 2.820

AS 62 1.792

AT 47 1.672

AU 44 1.643

AV 0 0.000

AW 461 2.664

AX 45 1.653

2ND

70 1.845 3085

3.489 1210

3.083 82

1.914 178

2.250 0

0.000 3156

3.499 1569

3.196 1667

3.222 1958

3.292 2519

3.401 64

1.806 124

2.093 0

0.000 2197

3.342 2345

3.370 988

2.995 51

1.708 4415

3.645 158

2.199 16

3RD

33 1.519

0 0.000 1191

3.076 28

1.447 39

1.591 31

1.491 0

0.000 55

1.740 593

2.773 231

2.364 2390

3.378 0

0.000 95

1.978 3

.477 1427

3.154 52

1.716 13013 4.114

0 0.000

0 0.000

74 1.869

0

SUM

339 2.530 3150

3.498 2455

3.390 110

2.041 286

2.456 31

1.491 3218

3.508 1634

3.213 3381

3.530 2222

3.347 5007

3.700 64

1.806 223

2.348 3

.477 4284 3.632 2459

3.391 14048 4.148

95 1.978 4415

3.645 693

2.841 61 ~-

1.204 0.000 1.785

APPENDIX 5.2


BIGRAM POSITION 1ST

AY 0 0.000

AZ 0 0.000

BA 1 5 7 9 3.198

BE 3186 3.503

BI 214 2.330

BL 217 2.336

BO 1 8 0 3 3.256

BR 1 4 1.146

BS 0 0.000

B T 0 0.000

BU 244 2.387

BY 9 .954

CA 1 8 3 7 3.264

CE 223 2.348

C H 7 3 1 . 8 6 3

CI 400 2.602

CK 0 0.000

CL 279 2.446

CO 1 5 1 4 3.180

CR 56 1.748

C T 0 0.000

2ND

7 6 3 2.883

1 5 1 2.179

0 0 .000

28 1 .447

0 0.000

216 2.334

0 0 .000

0 0 .000

0 0 .000

0 0.000

0 0 .000

0 0 .000

1 5 1 .176

0 0.000

1 4 1 .146

1 3 1.114

0 0 .000

0 0.000

0 0.000

9 .954

39 1 . 5 9 1

3RD

1 0 0 4 3 .002

0 0.000

47 1 .672

4 8 1 . 6 8 1

0 0.000

0 0.000

0 0.000

0 0.000

8 3 1 .919

1 3 1.114

0 0 .000

6 2 1 .792

0 0 .000

1 1 9 6 3.078

3267 3.514

0 0.000

1 7 0 6 3.232

0 0.000

2 1 1.322

0 0.000

4 58 2 . 6 6 1

SUM

1 7 6 7 3 .247

1 5 1 2.179

1 6 2 6 3 . 2 1 1

3 2 6 2 3 .513

214 2.330

433 2.636

1 8 0 3 3 .256

1 4 1 . 1 4 6

8 3 1 .919

1 3 1 . 1 1 4

244 2.387

7 1 1 . 8 5 1

1 8 5 2 3.268

1 4 1 9 3.152

3 3 5 4 3.526

413 2 .616

1 7 0 6 3 .232

2 7 9 2.446

1 5 3 5 3 .186

6 5 1 . 8 1 3

497 2.696

1 7 3

174 CHAPTER 5


BIGRAM POSITION 1ST

CU 148 2.170

CY 0 0.000

DA 1004 3.002

DD 0 0.000

DE 717 2.856

DG 0 0.000

DI 268 2.428

DL 0 0.000

DN 0 0.000

DO 2146 3.332

DR 238 2.377

DS 0 0.005

DU 234 2.369

DY 7 .845

E A 1296 3.113

EB 0 0.000

EC 10 1.000

ED 90 1.954

EE 0 0.050

EF 0 0.000

EG 35 1.544

2ND

0 0.000

0 0.000

44 1.643

24 1.380

204 2.310

78 1.892

0 0.000

19 1.279

3 .477

21 1.322

0 0.000

0 0.000

0 0.050

0 0.000 3589

3.555 13

1.114 119

2.076 16

1.204 5115

3.709 487

2.688 6 7

1.826

3RD

0 0.000

49 1.690

0 0.000

0 0.000 1851

3.267 3

.477 0

0.000 0

0.000 0

0.000 3

.477 0

0.000 204

2.310 0

0.000 401

2.603 529

2.723 0

0.000 0

0.000 1414

3.150 371

2.569 41

1.613 0

0.000

SUM

148 2.170

49 1.690 1048

3.020 24

1.380 2772

3.443 81

1.908 268

2.428 19

1.279 3

.477 2170

3.336 238

2.377 204

2.310 234

2.369 408

2.611 5414

3.734 13

1.114 129

2.111 1520

3.182 5486

3.739 528

2.723 102

2.009

APPENDIX 5.2


BIGRAM POSITION 1ST

EI 0 0.000

EK 0 0 .000

EL 1 7 6 2.246

EM 1 0 1 .000

EN 7 3 1 . 8 6 3

EO 0 0 . 0 0 0

EP 1 8 1 . 2 5 5

ER 3 .477

ES 0 0.000

ET 0 0.000

EU 0 0 .000

EV 1 5 8 8 3 . 2 0 1

EW 0 0 . 0 0 0

EX 7 .845

EY 4 0 8 2 . 6 1 1

FA 1 3 9 0 3.143

FE 1 2 3 3 3 . 0 9 1

FF 0 0 .000

FI 1 4 8 0 3 .170

FL 2 4 2 2.384

FO 1 2 0 4 3 . 0 8 1

2ND

46 1 .663

0 0.000

2 5 1 2 3 .400

0 0.000

1 1 5 8 3 .064

1 9 1 . 2 7 9

238 2.377

5130 3 .710

1 4 5 0 3 .161

1 8 6 2.270

0 0.000

1 0 1 . 0 0 0

1 5 9 2 . 2 0 1

454 2.657

34 1 . 5 3 1

0 0.000

0 0 .000

0 0 .000

0 0 .000

0 0 .000

0 0.000

3 R D

0 0.000

3 4 4 2.537

276 2 . 4 4 1

2 1 4 9 3 .332

8 0 3 7 3 .905

0 0 . 0 0 0

534 2 .728

1 6 4 6 3 .216

1 3 9 4 3 .144

567 2.754

5 .699

0 0 .000

8 0 3 2.905

3 4 1 . 5 3 1

3 6 4 5 3 .562

6 .778

1 0 2 1 3 .009

5 .699

0 0 .000

0 8 .000

0 0.000

SUM

4 6 1 . 6 6 3

3 4 4 2 .537

2 9 6 4 3.472

2 1 5 9 3 .334

9 2 6 8 3 . 9 6 7

19 1 .279

7 9 0 2 .898

6 7 7 9 3 . 8 3 1

2 8 4 4 3 .454

7 5 3 2 .877

5 .699

1 5 9 8 3.204

9 6 2 2 .983

4 9 5 2 .695

4 0 8 7 3 . 6 1 1

1 3 9 6 3.145

2 2 5 4 3 .353

5 . 6 9 9

1 4 8 0 3 .170

2 4 2 2 .384

1 2 0 4 3 .081

1 7 5

1 7 6 CHAPTER 5


BIGRAM POSITION 1ST

FR 4662 3.669

FT 0 0.000

FU 3 4 5 2.538

FY 0 0 .000

GA 5 8 3 2.766

GE 1 0 3 2 .013

GG 0 0 .000

GH 0 0 .000

GI

GL

GN

2

1

0

3 GO

GR

6 4 7 8 1 1

6 1 7 8 5

0 0 0 0

296 1 1 3

292 2.465

GS 0 D . O O O

GU 1 0 9 2.037

HA 5393 3.732

HE 2247 3 .352

HI 658 2.818

HN 0 0.000

HO 1 2 7 6 3.106

HR 0 0.000

2 N D

0 0 .000

0 0 .000

0 0 .000

0 0.000

0 0.000

69 1 . 8 3 9

35 1 .544

0 0.000

0 0.000

2 1 1 . 3 2 2

0 0.000

3 .477

0 0.000

0 0.000

0 0.000

1 4 3 1 7 4 .156

9 1 52 3.962

5500 3 .740

0 0 .000

6 4 8 2.812

1 0 1.000

3RD

0 0 .000

6 0 1 2.779

0 0.000

7 .845

1 3 1 .114

304 2 .483

0 0.000

517 2.713

0 0.000

0 PI. 0 0 0

9 4 1 . 9 7 3

0 0 .000

0 0.000

2 4 1 2.382

0 0.000

0 0.000

4 .602

0 0 .000

362 2.559

1 0 1 . 0 0 0

0 0.000

SUM

4662 3.669

6 0 1 2.779

3 4 5 2.538

7 .845

5 9 6 2.775

476 2.678

35 1.544

517 2.713

6 4 7 2 . 8 1 1

8 2 1.914

9 4 1 .973

1 2 9 9 3.114

292 2.465

2 4 1 2.382

1 0 9 2.037

1 9 7 1 0 4.295

1 1 4 0 3 4.057

6158 3.789

362 2.559

1 9 3 4 3.286

1 0 1 .000

APPENDIX 5 . 2


BIGRAM POSITION 1ST

H U 201 2 .303

HY 9 . 954

I A 0 0.000

I B 0 0 .000

I C 0 0 .000

I D 2 2 1 2 .344

I E 0 0 .000

I F 0 0 .000

I G 3 .477

I K 0 0 .000

I L 9 - 9 5 4

I M 0 0 .000

I N 1 8 3 1 3 . 2 6 3

I 0 1 3 1 . 1 1 4

I P 0 0 .000

I R 46 1 . 6 6 3

I S 5 . 699

I T 59 1 . 7 7 1

IV 4 .602

I Z 0 0 .000

J A 261 2 .417

2ND

361 2 .558

0 0 .000

2 1 1 .322

11 1 . 0 4 1

447 2 .650

666 2 .823

433 2 .636

999 3 .000

6 3 1 2 . 8 0 0

1 4 2 6 3 .154

3093 3 .490

1 6 4 9 3 .217

2217 3 .346

30 1 . 4 7 7

1 3 4 2 .127

687 2 .837

839 2 .924

7847 3 .895

877 2 .943

1 3 8 2 .140

0 0 .000

3RD

0 0 .008

0 0 .000

44 1 . 6 4 3

0 0 .000

28 1 .447

2205 3 .359

0 0 .000

0 0 .000

0 0 .000

0 0 .000

4 27 2 .630

7 3 1 .863

698 2 .844

47 1 . 6 7 2

2 54 2 .405

292 2 .465

5199 3 .716

309 2 .490

0 0 .000

5 .699

0 0 .000

SUM

562 2 .750

9 .954

6 5 1 . 8 1 3

11 1 . 0 4 1

4 7 5 2 .677

3172 3 . 5 0 1

4 3 3 2 .636

999 3 .000

634 2 .802

1 4 2 6 3 .154

3529 3 .548

1 7 2 2 3 .236

4746 3 .676

9 0 1 . 9 5 4

388 2 .589

1 0 2 5 3 . 0 1 1

6 0 4 3 3 . 7 8 1

8 2 1 5 3 .915

8 8 1 2 .945

1 4 3 2 . 1 5 5

2 6 1 2 .417

1 7 7

1 7 8 CHAPTER 5


BIGRAM POSITION 1ST

J E 9 7 1 . 9 8 7

JI 7 . 8 4 5

J O 5 3 9 2 . 7 3 2

J U 1 1 4 7 3 . 0 6 0

K A 48 1 . 6 8 1

K E 5 2 8 2 . 7 2 3

K I 5 2 9 2 . 7 2 3

KL 0 0 . 0 0 0

K N 1 1 3 6 3 . 0 5 5

K O 11 1 . 0 4 1

KS 0 0 .000

LA 1 6 5 4 3 . 2 1 9

LB 0 0 .000

LD 0 0 .000

LE 1 2 2 8 3 .089

LF 0 0 .000

LG 0 0 . 0 0 0

L I 2835 3 . 4 5 3

LK 0 0 . 0 0 0

LL 0 0 . 0 0 0

LM 0 0 . 0 0 0

2ND

0 0 .000

0 0 . 0 0 0

0 0 .000

0 0 .000

20 1 . 3 0 1

0 0 .000

6 2 1 . 7 9 2

3 . 4 7 7

0 0 . 0 0 0

0 0 .000

0 0 .000

6 6 3 2 . 8 2 2

0 0 . 0 0 0

3 . 4 7 7 118

2 . 0 7 2 0

0 . 0 0 0 6

.778 7 9

1 . 8 9 8 0

0 .000 1 8

1 . 2 5 5 0

0 . 0 0 0

3RD

0 0 . 0 0 0

0 0 .000

0 0 .000

0 0 .000

0 0 . 0 0 0

3 0 4 8 3 .484

0 0 .000

0 0 .000

0 0 . 0 0 0

0 0 .000

1 8 1 . 2 5 5

1 0 1 . 0 0 0

7 . 8 4 5 1 2 6 4

3 . 1 0 2 8 6 6

2 .938 3 8 8

2 . 5 8 9 0

0 . 0 0 0 0

0 . 0 0 0 3 6 5

2 .562 5 3 7 9

3 . 7 3 1 1 5 7

2 . 1 9 6

SUM

9 7 1 . 9 8 7

7 . 8 4 5

5 3 9 2 . 7 3 2

1 1 4 7 3 .060

6 8 1 . 8 3 3

3 5 7 6 3 . 5 5 3

5 9 1 2 . 7 7 2

3 . 4 7 7 1 1 3 6

3 . 0 5 5 11

1 . 0 4 1 1 8

1 . 2 5 5 2327

3 .367 7

. 8 4 5 1 2 6 7

3 . 1 0 3 2 2 1 2

3 . 3 4 5 3 8 8

2 .589 6

. 7 7 8 2914

3 .464 365

2 .562 5 3 9 7

3 .732 1 5 7

2 .196

APPENDIX 5.2


BIGRAM POSITION 1ST

LO 2032 3.308

LP 0 0.000

LS 0 0.000

LT 0 0.000

LU 144 2.158

LV 0 0.000

LY 5 .699

MA 3631 3.560

MB 0 0.000

ME 504 2.702

MI 895 2.952

MM 0 0.000

MN 0 0.000

MO 3751 3.574

MP 0 0.000

MS 0 0.000

MU 1961 3.292

MY 35 1.544

NA 350 2.544

NC 0 0.000

ND 0 0.000

2N D

2 54 2.405

0 0.000 1245

3.095 4

.602 449

2.652 4

.602 0

0.000 0

0.000 0

0.000 19

1.279 14

1.146 10

1.000 0

0.000 0

0.000 0

0.000 0

0.000 7

.845 0

0.000 12

1.079 539

2.732 102

2.009

3RD

11 1.041

316 2.500

24 1.380

508 2.706

0 0.000

0 0.000 1930

3.286 54

1.732 82

1.914 6252

3.796 0

0.000 0

0.000 43

1.633 0

0.000 178

2.250 161

2.207 0

0.000 132

2.121 10

1.000 10

1.000 2140

3.330

SUM

2297 3.361

316 2.500 1269

3.103 512

2.709 593

2.773 4

.602 1935

3.287 3685

3.566 82

1.914 6775

3.831 909

2.959 10

1.000 43

1.633 3751

3.574 178

2.250 161

2.207 1968

167 2.223

372 2.571

549 2.740 2242

3.351

3.294

179

1 8 0 CHAPTER 5


BIGRAM POSITION 1ST

NE 1 1 9 6 3.078

NG 0 0.000

NI 1 8 1 2.258

NK 0 0.000

NL 0 0 .000

NN 0 0.000

NO 330 2.519

NS 0 0.000

NT 0 0 .000

N U 6 2 1.792

NV 0 0.000

NY 0 0.000

OA 1 3 1 .114

OB 8 .903

oc 0 0.000

OD 28 1.447

OE 0 0.000

OF 0 0 .000

OG 0 0.000

OH 3 8 1.580

01 2 5

2 N D

5 5 2 2.742

0 0.000

1 1 3 2.053

0 0.000

1 7 4 7 3.242

49 1 .690

7 5 5 2.878

0 0.000

1 8 7 7 3.273

0 0.000

7 .845

0 0.808

608 2.784

8 1 1.908

1 2 3 2.090

3 9 5 2.597

746 2.873

67 1 .826

7 8 1.892

362 2.559

1 8 9 1 .398 2.276

3 R D

1 7 0 1 3 .231

1 2 4 5 3.095

0 0.000

3 0 8 2 .489

0 0.000

2 5 1 .398

7 .845

304 2.483

1 3 4 9 3 .130

5 .699

0 0.000

1 1 6 1 3.065

0 0 .000

4 ,602

1 0 1.000

1 0 5 3 3.022

1 4 1.146

63 1.799

0 0.000

0 0.000

0 0.000

SUM

3 4 4 9 3.538

1 2 4 5 3 .095

294 2.468

3 08 2.489

1 7 4 7 3.242

74 1.869

1 0 9 2 3.038

304 2.483

3226 3.509

67 1.826

7 .845

1 1 6 1 3.065

6 2 1 2.793

9 3 1.968

1 3 3 2.124

1 4 7 6 3.169

7 6 0 2 .881

1 3 0 2.114

7 8 1.892

400 2.602

214 2.330

A P P E N D I X 5.2

BIGRAM F R E Q U E N C I E S FOR WORDS OF L E T T E R LENGTH 4


OK 23 1 .362

OL 6 .778

OM 0 0.000

ON 2 4 2 2 3.384

00 0 0.000

OP 3 2 2 2 .508

OR 27 1 . 4 3 1

0s 0 0.000

OT 3 .477

ou 27 1 . 4 3 1

OV 1 2 5 1 3 .097

ow 58 1 . 7 6 3

ox 1 0 1.000

OY 0 0.000

P A 1 6 3 8 3 .214

P E 1 0 4 2.017

PH 65 1 . 8 1 3

P I 269 2.430

PL 560 2.748

PO 6 6 6 2 .823

P R 3 0 1.477

2 N D

3 9 1 . 5 9 1

1 3 6 3 3 .134

2934 3.467

1 8 5 4 3 .268

3703 3.569

330 2.519

4755 3,677

2065 3.315

9 9 3 2.997

1 5 8 2 3.199

410 2.613

1 2 0 9 3.082

0 0 .000

1 7 0 2.230

28 1 .447

332 2 . 5 2 1

0 0 .000

3 4 1 . 5 3 1

0 0 .000

552 2.742

0 0.000

3 R D

1 0 7 0 3.029

267 2.427

4952 3 .695

867 2.938

0 0 .000

302 2.480

4 5 1 2.654

6 4 1 .806

373 2.572

1 4 1.146

0 0.000

1 2 8 6 3 .109

5 .699

3 .477

40 1 . 6 0 2

558 2.747

0 0.000

0 0 .000

0 0.000

0 0 .000

0 0 .000

S U M

1 1 3 2 3 .054

1 6 3 6 3 .214

7 8 8 6 3 .897

5 1 4 3 3 . 7 1 1

3 7 0 3 3 .569

9 54 2 .980

5233 3 .719

2 1 2 9 3.328

1 3 6 9 3.136

1 6 2 3 3.210

1 6 6 1 3.220

2 5 5 3 3 .407

1 5 1 . 1 7 6

1 7 3 2.238

1 7 0 6 3 .232

9 9 4 2.997

6 5 1 . 8 1 3

3 0 3 2 . 4 8 1

5 6 0 2 .748

1 2 1 8 3 .086

3 0 1 . 4 7 7

181

1 8 2 CHAPTER 5


BIGRAM POSITION 1 S T 2ND

PS 0 0 0 .000 0 .000

PT 0 0 0 .000 0 .000

PU 1 8 6 3 2 2 .270 1 . 5 0 5

PY 0 0 0 .000 0 .000

QU 1 5 0 1 .176 0 .000

RA 5 6 1 273 2 .749 2 .436

RB 0 0 0 .000 0 .000

RC 0 1 3 0 .000 1 . 1 1 4

RD 0 0 0 .000 0 .000

RE 706 8 6 0 2 .849 2.934

RF 0 0 0 .000 0 .000

RG 0 2 1 0 .000 1 .322

R I 424 1 7 6 2 .627 2 .246

RK 0 0 0 .000 0 .000

RL 0 0 0 .000 0 .000

RM 0 253 0 .000 2 .403

R N 0 0 0 .000 0 .000

RO 1 1 6 2 4586 3 . 0 6 5 3 .661

RP 0 0 0 .000 0 .000

R R 0 0 0 .000 0 .000

RS 0 0 0 .000 0 .000

3RD SUM

1 6 4 1 6 4 2 .215 2 . 2 1 5

240 240 2 .380 2.380

0 218 0 .000 2 .338

38 38 1 . 5 8 0 1 .580

0 1 5 0 .000 1 . 1 7 6

1 9 8 5 3 1 . 2 7 9 2 .931

27 27 1 . 4 3 1 1 . 4 3 1

0 1 3 0 .000 1 .114

747 747 2 .873 2 .873

7 3 7 5 8 9 4 1 3 . 8 6 8 3 .951

3 3 .477 .477

0 2 1 0 .000 1 . 3 2 2

6 606 .778 2 .782 1 4 7 5 1 4 7 5

3 .169 3 .169 283 283

2 .452 2 .452 792 1 0 4 5

2 .899 3 .019 5 5 5 5 5 5

2 .744 2 .744

1 . 8 8 1 3 .765 7 6 5824

1 3 1 3 1 .114 1 .114

22 22 1 . 3 4 2 1 . 3 4 2

280 288 2 .459 2 .459

APPENDIX 5.2


BIGRAM POSITION 1ST

RT 0 0.000

RU 2 2 2 2.346

RX 0 0.000

RY 0 0 .000

SA 3 2 1 1 3.507

sc 1 5 1 . 1 7 6

SE 1 1 6 0 3.064

SH 6 2 8 2.798

SI 8 3 7 2.923

SK 5 2 1 .716

SL 1 6 6 2.220

SM 7 .845

SN 7 1 1 . 8 5 1

SO 2387 3 .378

SP 1 3 9 2.143

ss 0 0 .000

S T 448 2 . 6 5 1

SU 1 6 6 5 3 .221

sw 29 1 .462

SY 0 0.000

TA 1 0 2 2 3 .009

2ND

6 6 1.820

266 2.425

0 0.000

0 0 .000

0 0.000

0 0 .000

6 7 5 2.829

0 0 .000

44 1 . 6 4 3

1 8 1 .255

5 .699

0 0 .000

0 0.000

0 0.000

0 0.000

0 0.000

0 0.000

0 0.000

0 0.000

0 0.000

1 5 9 2 . 2 0 1

3 R D

8 4 5 2.927

1 4 1.146

8 .903

1 0 5 0 3 .021

0 0.000

6 .778

1 0 5 7 3.024

342 2.534

0 0.900

2 32 2.365

0 0 .000

0 0.000

0 0.000

1 0 8 0 3.033

3 .477

1 0 9 2 3 .038

6087 3.784

0 0.000

0 0 .000

1 9 2 2.283

173 2.238

SUM

9 1 1 2.960

5 0 2 2 . 7 0 1

8 . 9 0 3

1 0 5 0 3 . 0 2 1

3 2 1 1 3.507

2 1 1 .322

2 8 9 2 3 .461

9 7 0 2.987

8 8 1 2 .945

3 0 2 2 .480

1 7 1 2 .233

7 . 8 4 5

7 1 1 . 8 5 1

3467 3 .540

1 4 2 2 .152

1 0 9 2 3 .038

6 5 3 5 3.815

1 6 6 5 3 . 2 2 1

2 9 1 . 4 6 2

1 9 2 2.283

1 3 5 4 3 .132

1 8 3

1 8 4 CHAPTER 5


B I G R A M POSITION 1ST

TC 0 0 .000

TE 6 9 3 2 . 8 4 1

TH 24777 4 . 3 9 4

T I 1 8 1 8 3 .260

TO 1 3 8 4 3 . 1 4 1

TR 4 5 3 2 . 6 5 6

TS 0 0 . 0 0 0

TT 0 0 .000

TU 282 2 .450

TW 7 . 8 4 5

TY 200 2 . 3 0 1

U A 0 0 . 0 0 0

U B 0 0 .000

uc 0 0 . 0 0 0

U D 0 0 . 0 0 0

U E 0 0 . 0 0 0

OF 0 0 .000

UG 2 1 1 . 3 2 2

U I 0 0 .000

U K 0 0 .000

U L 0 0 . 0 0 0

2ND

5 . 6 9 9

2 1 9 2 . 3 4 0

0 0 . 0 0 0

1 0 1 . 0 0 0

1 6 3 2 .212

0 0 .000

0 0 . 0 0 0

4 . 6 0 2

3 , 4 1 7

0 0 .000

0 0 . 0 0 0

2 8 1 . 4 4 7

7 8 1 . 8 9 2

2 3 6 6 3 .374

4 6 1 . 6 6 3

26 1 . 4 1 5

5 . 6 9 9

7 5 1 . 8 7 5

8 6 1 . 9 3 4

1 4 1 . 1 4 6

5 6 1 2 .749

3RD

0 0 . 0 0 0

9 9 0 2 . 9 9 6

8 1 6 5 3 .912

0 0 . 0 0 0

1 9 0 3 3 . 2 7 9

0 0 .000

5 3 6 2 . 7 2 9

1 2 1 . 0 7 9

0 0 . 0 0 0

0 0 .000

472 2 . 6 7 4

0 0 .000

1 4 8 2 . 1 7 0

0 0 . 0 0 0

2 3 1 . 3 6 2

3 8 9 2 .590

0 0 . 0 0 0

6 4 1 . 8 0 6

0 0 .000

3 . 4 7 7

9 4 1 . 9 7 3

SUM

5 . 6 9 9 1 9 0 2

3 .279 3 2 9 4 2 4 .518

1 8 2 8 3 . 2 6 2

3450 3 . 5 3 8

4 5 3 2 .656

536 2 . 7 2 9

1 6 1 . 2 0 4

2 8 5 2 . 4 5 5

7 . 8 4 5 6 7 2

2 . 8 2 7 2 8

1 . 4 4 7 2 2 6

2 .354 2 3 6 6

3 . 3 7 4 6 9

1 . 8 3 9 4 1 5

2 .618 5

. 6 9 9 1 6 0

2 . 2 0 4 8 6

1 . 9 3 4 1 7

1 . 2 3 0 6 5 5

2 . 8 1 6

APPENDIX 5.2


BIGRAM POSITION 1ST

UM 0 0.000

UN 1 2 2 2.086

UP 495 2.695

UR 2 1 1 .322

US 6 7 5 2.829

UT 6 .778

ux 0 0 .000

UY 0 0.000

uz 0 0.000

VA 1 0 9 2 .037

VD 0 0 .000

VE 8 5 7 2.933

VI 252 2 . 4 0 1

vo 9 0 1 .954

VY 0 0.000

W A 1 1 1 7 3 .048

W D 0

W E 5289 3.723

W H 4407 3.644

WI 1 0 3 2 8 4.014

WK 0 0.000

9 . 0 0 0

2ND

8 9 1 . 9 4 9

447 2.650

1 4 1.146

8 0 1 2.904

2147 3.332

2 1 2 2 .326

0 0 .000

3 1 1 .491

1 6 1.204

1 2 1 . 0 7 9

0 0 .000

2759 3 . 4 4 1

7 2 1 .857

0 0 .000

0 0.000

470 2.672

0 0 .000

50 1 . 6 9 9

0 0 .000

2 2 1 . 3 4 2

0 0.000

3RD

1 9 1.279

1 6 1 .204

20 1 . 3 0 1

1 4 9 7 3 .175

387 2.588

6 1 1 . 7 8 5

30 1 . 4 7 7

0 0 .000

0 0 .000

4 .602

4 .602

5 6 6 1 3.753

0 0.000

0 0.000

54 1 . 7 3 2

4 . 6 0 2

3 .477

1 2 1.079

0 0.000

0 0 .000

1 4 1.146

SUM

1 0 8 2.033

5 8 5 2.767

5 2 9 2 .723

2 3 1 9 3 .365

3 2 0 9 3 .506

279 2 .446

3 0 1 . 4 7 7

3 1 1 . 4 9 1

1 6 1.204

1 2 5 2 .097

4 . 6 0 2

9 2 7 7 3.967

3 2 4 2 . 5 1 1

9 0 1 .954

5 4 1 . 7 3 2

1 5 9 1 3 .202

3 .477

5 3 5 1 3.728

4407 3.644

1 0 3 5 0 4 .015

1 4 1 . 1 4 6

1 8 5

1 8 6 CHAPTER 5


BIGRAM POSITION 1 S T

WL 0 0 000

WN 0 0 000

WO 214 3 084

WR 1 2 1 .079

ws 0 0 .000

XE 0 0 .000

X I 0 0 .000

XT 0 0 .000

Y A 69 1 .839

Y D 0 0 .000

Y E 694 2 .841

YM 0 0 .000

Y N 0 0 .000

Y O 1227 3 .089

YP 0 0 .000

Y R 0 0 .000

YS 0 0 .000

YT 0 0 .000

YU 6 .I78

ZE 37 1 .568

2 1 1 6 1 .204

2ND

0 0 .000

1 3 1 .114

0 0 .000

0 0 .000

0 0 .000

1 7 1 . 2 3 0

4 5 1 . 6 5 3

0 0 .000

0 0 .000

0 0 .000

415 2 .618

9 .954

5 .699

0 0 .000

200 2 .301

9 , 9 5 4

0 0 .000

3 5 1 . 5 4 4

0 0 .000

0 0 .000

0 0 .000

3RD

27 1 . 4 3 1

1 1 6 9 3 .068

0 0 .000

0 0 .000

297 2 .473

0 0 .000

1 6 1 . 2 0 4

4 54 2 .657

0 0 .000

5 . 699

0 0 .000

0 0 .000

0 0 .000

0 0 .000

0 0 .000

0 0 .000

989 2 .995

4 . 602

0 0 .000

1 6 3 2 .212

1 3 1 .114

SUM

27 1 . 4 3 1

1 1 8 2 3 .073

1214 3 .084

1 2 1 . 0 7 9

297 2 .473

1 7 1 . 2 3 0

6 1 1 . 7 8 5

454 2 .657

6 9 1 .839

5 .699 1 1 0 9

3 .045 9

.954 5

.699 1 2 2 7

3 .089 200

2 . 3 0 1 9

, 9 5 4 989

2 .995 39

1 . 5 9 1 6

200 2 .301

29 1 . 4 6 2

, 7 7 8

APPENDIX 5.2 187


BIGRAM POSITION 1ST 2ND 3RD SUM

ZO 11 0 0 11 1.041 0.000 0.000 1.041

ZY 0 0 14 14 0.000 0.000 1.146 1.146

z z 0 0 115 115 0.000 0.000 2.061 2.061

1 8 8 C H A P T E R 5


BIGRAM P O S I T I O N 1 S T 2 N D 3 RD 4TH SUM

AA 7 .845

A B 2 1 5 1 3 .333

AC 1 0 9 2.037

AD 308 2.489

A F 1 0 7 0 3 .029

AG 6 8 6 2.836

AH 1 0 9 2 .037

A 1 45 1 . 6 5 3

AJ 0 0.000

AK 0 0.000

A L 8 7 5 2.942

AM 3 9 6 2.598

AN 1 7 6 2.246

A 0 0 0.000

AP 204 2.310

AR 410 2.613

A S 489 2.689

A T 69 1.839

0 0.000

438 2 . 6 4 1

3 0 9 2.490

2 37 2.375

5 .699

2 4 1 2 .382

4 .602

5 8 1 2.764

247 2.393

6 4 4 2.809

8 1 0 2.908

362 2 .559

9 9 4 2.997

0 0.000

384 2.584

1 9 3 4 3.286

884 2 .946

1 4 4 9 3 .161

1 0 1 .000

3 .477

1 6 2 5 3 .211

5 4 1 2.733

1 7 1 2.233

3 1 5 2.498

0 0.000

1 0 8 8 3.037

0 0.000

1 2 0 2 .079

1 0 6 6 3.028

3 0 5 2 .484

1 3 1 2 3.118

1 7 1 .230

1 2 2 2.086

2670 3 .427

1 0 4 1 3 .017

1 2 6 0 3 .100

0 0.000

0 0.000

1 4 1 . 1 4 6

2 8 5 2 .455

3 .477

0 0.000

26 1 .415

7 .845

0 0 .000

225 2.352

1 6 1 6 3.208

111 2.045

1 2 2 8 3.089

0 0.000

3 2 1 .505

394 2.595

468 2 .670

7 3 6 2.867

1 7 1 .230

2 5 9 2 3.414

2057 3.313

1 3 7 1 3.137

1 2 4 9 3 .097

1 2 4 2 3 .094

1 3 9 2.143

1 7 2 1 3.236

247 2.393

9 8 9 2.995

4367 3.640

1 1 7 4 3.070

3 7 1 0 3.569

1 7 1 . 2 3 0

7 4 2 2.870

5408 3.733

2 8 8 2 3 .460

3 5 1 4 3.546

AU 8 274 8 0 290 .903 2.438 .903 0.000 2.462

AV 6 2 3 3 2 4 1 6 0 8 1 0 1.792 2 .521 2.619 0 .000 2.908

AW 1 8 5 1 2 9 8 1 5 310 2.267 1 . 0 7 9 1 . 9 9 1 1 . 1 7 6 2 .491

APPENDIX 5.2


BIGRAM POSITION 1ST

AX 0 0.000

AY 0 0.000

A2 0 0.000

BA 745 2.872

BB 0 0.000

BE 1556 3.192

BI 269 2.430

BL 654 2.816

BO 668 2.825

BR 984 2.993

BS 0 0.000

BT 0 0.000

BU 372 2.571

BY 16 1.204

CA 731 2.864

cc 0 0.000

CE 121 2.083

CH 925 2.966

CI 161 2.207

CK 0 0.000

CL 1097 3.040

2ND

65 1.813 211

2.324

38 1.580

0 0.000

7 .845

0 0.000

7 .845

0 0.000

2115 3.325

0 0.000

0 0.000

b7 0.000

18 1.255

4 .602 86

1.934

43 1.633

146 2.164

3 .477

7 .845

0 0.000

0 0.000

3RD

0 0.000

74 1.869

44 1.643

61 1.785

60 1.778 144

2.158

77 1.886

287 2.458

162 2.210

3 .477

0 0.000

12 1.079

20 1.301

0 0.000

337 2.528

0 0.000

187 2.272

3 .477

12 1.079 112

2.049 81

4TH SUM

19 84 1.279 1.924 384 669

2.584 2.825

0 82 0.000 1.914

0 806 0.000 2.906

0 67 0.000 1.826 161 1861

2.207 3.270

21 374 1.322 2.573

0 94 1 0.d00 2.974

4 2949 .602 3.470

0 987 0.000 2.994

80 80 1.903 1.903

114 126 2.057 2.100

0 410 0.000 2.613

58 78 1.763 1.892

0 1154 0.c100 3.062

0 43 0.000 1.633 2712 3166 3.433 3.501

4479 5410 3.651 3.733

0 180 0.000 2.255 1000 1112 3.000 3.046

0 1178 1.908 0.000 3.071

189

190 C H A P T E R 5



CO 2783 3.445

C R 457 2 .660

cs 0 0 .000

C T 0 0.000

CU 1 1 3 2.053

CY 28 1.447

DA 4 1 2 2 .615

DD 0 0.000

DE 5 2 2 2.718

DG 0 0.000

D I 1 1 2 2.049

DL 0 0.000

DM 0 0.000

DO 450 2.653

OR 7 7 5 2.889

D S 0 0 .000

DT 0 0.000

DU 5 2 1 . 7 1 6

DW 11 1 . 0 4 1

DY 45 1 . 6 5 3

EA 573 2.758

2ND

1 3 4 2.127

8 2 1.914

0 0.000

4 2 1 . 6 2 3

1 3 1.114

0 0.000

50 1.699

2 1 1 2.324

208 2.318

4 4 1 .643

11 1 . 0 4 1

7 . 8 4 5

3 7 1.568

2 1 1 . 3 2 2

0 0.000

0 0.000

0 0.000

2 5 1 .398

11 1 . 0 4 1

0 0.000

3 8 6 5 3.587

3 R D

1 8 1 . 2 5 5

0 0.000

0 0.000

1 0 0 2.000

88 1.944

0 0 .000

3 2 1 2 .507

3 4 1 . 5 3 1

1 8 1 4 3.259

1 4 3 2 .155

225 2.352

5 9 1 . 7 7 1

0 0 .000

30 1.477

9 .954

1 9 1 .279

1 4 1 . 1 4 6

1 3 1 . 1 1 4

0 FI. 0 0 0

0 0.000

2 0 8 2 3.318

4TH

0 0 .000

0 0 .000

7 .845

8 7 1 .940

0 0.000

47 1 .672

5 .699

0 0.000

5 58 2.747

0 0.000

0 0.000

0 0 .000

0 0.000

11 1 . 0 4 1

0 0.000

1 7 3 6 3.240

0 0.000

3 .477

0 0.000

547 2 .738

1 2 1.079

S U M

2 9 3 5 3 .468

5 3 9 2 .732

7 .845

2 29 2.360

214 2.330

7 5 1 .875

7 8 8 2.897

245 2.389

3 1 0 2 3 .492

1 8 7 2.272

3 4 8 2.542

66 1 .820

37 1.568

5 1 2 2 .709

7 84 2 .894

1 7 5 5 3 .244

1 4 1 .146

9 3 1 .968

2 2 1 .342

592 2 .772

6 5 3 2 3 .815

APPENDIX 5 . 2

B I G R A M FREQUENCIES FOR WORDS OF LETTER LENGTH 5

BIGRAM POSITION 1ST

EB 0 0 .000

EC 0 0 . 0 0 0

E D 8 9 1 . 9 4 9

E E 0 0 .000

EF 0 0 .000

EG 1 4 1 . 1 4 6

E H 0 0 .000

E I 104 2 .017

E K 0 0 .000

E L 77 1 . 8 8 6

EM 64 1 . 8 0 6

E N 303 2 . 4 8 1

EO 0 0 .000

EP 6 . 778

E Q 90 1 . 9 5 4

E R 79 1 . 8 9 8

ES 3 1 1 . 4 9 1

ET 11 1 . 0 4 1

E U 0 0 .000

EV 597 2 . 7 7 6

EW 0 0 .000

2ND

44 1 . 6 4 3

18 1 . 2 5 5

4 1 1 . 6 1 3

8 8 3 2.946

27 1 . 4 3 1

628 2 .798

5 . 699

7 6 3 2 .883

0 0 .000

474 2 .676

3 1 1 . 4 9 1

6 8 5 2 .836

0 0 .000

1 2 3 2 .090

0 0 .000

494 2 .694

1 6 6 2 .220

1 2 8 2 .107

0 0 .000

1 0 8 8 3 .031

1 5 1 2 .179

3RD

4 . 602

2 6 1 2 .417

237 2 .375

930 2 .968

1 0 1 . 0 0 0

1 8 1 . 2 5 5

0 0 .000

2688 3 .429

1 5 1 2 .179

490 2 .690

589 2 .770

486 2.687

0 0 .000

216 2 .334

0 0 .000

4347 3 .638

2095 3 . 3 2 1

1 7 8 2 .250

9 .954

3 . 477

5 1 1 .708

4TH

0 0 .000

0 0 .000

2 8 2 5 3 . 4 5 1

6 6 5 2 .823

210 2 .322

0 0 . 0 0 0

0 0 .000

0 0 .000

9 5 9 7 8 752 8 7 6

1 9 279 686 227

3 . 477

1 2 6 2 .100

0 0 . 0 0 0

7346 3 . 8 6 6

3937 3 . 5 9 5

297 2 .473

0 0 .000

0 0 .000

7 1 1 . 8 5 1

SUM

4 8 1 . 6 8 1

279 2 .446

3192 3 .504

2478 3 .394

247 2 .393

660 2 .820

5 . 6 9 9 3555

3 . 5 5 1 246

2 .391 1 7 9 3

3 .254 7 0 3

2 .847 3160

3 .500 3

. 477 471

2 . 6 7 3 9 0

1 . 9 5 4 1 2 2 6 6 4 .089

6229 3 .794

614 2 .788

9 .9 54 1 6 8 8

3 .227 273

2 .436

1 9 1

1 9 2 CHAPTER 5


BIGRAM POSITION 1ST 2N D

EX 151 8 9 2 .179 1 . 9 4 9

EY 0 6 0 .000 . 7 7 8

FA 6 2 8 0 2 . 7 9 8 0 . 0 0 0

FE 2 4 5 0 2 .389 0 . 0 0 0

FF 0 8 0 0 . 0 0 0 1 . 9 0 3

F I 2400 0 3 . 3 8 0 0 .000

FL 3 9 5 0 2 .597 0 . 0 0 0

FO 1 1 7 1 0 3 .069 0 . 0 0 0

FR 5 4 1 0 2 . 7 3 3 0 .000

FS 0 0 0 .000 0 .000

FT 0 1 4 3 8 0 .000 3 . 1 5 8

FU 234 0 2 .369 0 .000

GA 1 6 0 5 7 8 2 .204 2 . 7 6 2

G E 3 44 .477 1 . 6 4 3

G G 0 0 0 . 0 0 0 0 . 0 0 0

G H 1 5 0 1 . 1 7 6 0 .000

G I 6 6 5 4 2 . 8 2 3 .602

G L 2 0 1 0 2 . 3 0 3 0 .000

GM 0 0 0 . 0 0 0 0 . 0 0 0

GN 0 0 0 . 0 0 0 0.000

G O 5 2 1 9 2 . 7 1 7 .954

3RD

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

1 1 2 2 . 0 4 9

0 0 . 0 0 0

0 0 . 0 0 0

6 3 1 . 7 9 9

0 0 .000

El 0 . 0 0 0

0 0 . 0 0 0

1 2 2 2 . 0 8 6

1 7 1 . 2 3 0

4 56 2 . 6 5 9

290 2 .462

1 8 1 . 2 5 5

2 4 1 3 3 . 3 8 3

1 6 2 2 .210

5 6 1 . 7 4 8

4 . 6 0 2

6 8 1 . 8 3 3

6 9 1 . 8 3 9

4TH

9 3 1 . 9 6 8

3 4 2 2 . 5 3 4

0 0 . 0 0 0

8 4 1 . 9 2 4

1 8 9 2 . 2 7 6

0 0 .000

0 0 . 0 0 0

0 0 .000

0 0 .000

1 2 1 . 0 7 9

1 6 2 2 . 2 1 0

0 0 . 0 0 0

0 0 . 0 0 0

1 0 4 0 3 . 0 1 7

3 . 4 7 7

1 3 8 2 . 1 4 0

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

7 . 8 4 5

7 2 1 . 8 5 7

SUM

3 3 3 2 . 5 2 2

3 4 8 2 . 5 4 2

6 2 8 2 .798

4 4 1 2 . 6 4 4

2 6 9 2 . 4 3 0

2 4 0 0 3 . 3 8 0

4 5 8 2 . 6 6 1

1 1 7 1 3 . 0 6 9

5 4 1 2 . 7 3 3

1 2 1 . 0 7 9

1 7 2 2 3 . 2 3 6

2 5 1 2 . 4 0 0

1 1 9 4 3 .077

1 3 7 7 3 . 1 3 9

2 1 1 . 3 2 2

2 5 6 6 3 . 4 0 9

8 3 1 2 . 9 2 0

2 57 2 . 4 1 0

4 . 6 0 2

7 5 1 . 8 7 5

6 7 1 2 . 8 2 7

APPENDIX 5 .2



G R 1 7 6 3 3 . 2 4 6

GS 0 0 . 0 0 0

G U 2 3 3 2 .367

G Y 4 . 6 0 2

HA 6 1 1 2 . 7 8 6

H E 8 2 3 2 . 9 1 5

H I 1 0 5 2 . 0 2 1

H N 0 0 . 0 0 0

H O 1 4 0 4 3 . 1 4 7

H R 0 0 . 0 0 0

HS 0 0 . 0 0 0

HT 0 0 . 0 0 0

H U 399 2 . 6 0 1

H Y 6 . 7 7 8

I A 0 0 . 0 0 0

IB 0 0 . 0 0 0

IC 0 0 . 0 0 0

I D 2 1 1 2 . 3 2 4

I E 0 0 . 0 0 0

I F 0 0 . 0 0 0

I G 0 0 . 0 0 0

2ND

5 1 1 . 7 0 8

0 0 . 0 0 0

0 0 . 0 0 0

1 4 1 . 1 4 6

9 2 4 2 . 9 6 6

8 5 0 7 3 . 9 3 0

6 2 0 9 3 . 7 9 3

0 0 . 0 0 0

2 4 2 1 3 .384

7 1 3 2 . 8 5 3

0 0 . 0 0 0

0 0 . 0 0 0

27 1 . 4 3 1

7 , 8 4 5

8 7 1 . 9 4 0

9 3 1 . 9 6 8

1 9 1 . 2 7 9

2 57 2 . 4 1 0

534 2 . 7 2 8

1 8 0 2 . 2 5 5

2468 3 . 3 9 2

3RD

1 4 9 2 . 1 7 3

0 0 .000

111 2 . 0 4 5

0 0 .000

0 0 .000

1 7 1 7 3 . 2 3 5

4 . 6 0 2

6 . 7 7 8

8 . 9 0 3

5 . 6 9 9

0 0 .000

0 0 .000

0 0 .000

0 0 . 0 0 0

1 4 4 2 . 1 5 8

1 2 1 . 0 7 9

4 2 4 5 3 . 6 2 8

2 2 9 2 . 3 6 0

594 2 . 7 7 4

1 9 9 2 . 2 9 9

26 1 . 4 1 5

4TH

0 0 . 0 0 0

1 9 2 2 . 2 8 3

0 0 . 0 0 0

2 3 1 . 3 6 2

0 0 . 0 0 0

11 1 . 0 4 1

5 . 6 9 9

0 0 . 0 0 0

4 . 6 0 2

0 0 . 0 0 0

2 8 1 . 4 4 7

2 4 1 3 3 . 3 8 3

0 0 . 0 0 0

4 . 6 0 2

1 2 3 2 . 0 9 0

0 0 . 0 0 0

5 5 5 2 . 7 5 2

3 3 3 2 . 5 2 2

1 1 2 2 . 0 4 9

2 7 1 . 4 3 1

0 0 . 0 0 0

SUM

1 9 6 3 3 . 2 9 3

1 9 2 2 . 2 8 3

344 2 . 5 3 7

4 1 1 . 6 1 3

1 5 3 5 3 .186 1 1 0 5 8 4 . 0 4 4

6 3 2 3 3 . 8 0 1

6 . 7 7 8 3 8 3 7

3 . 5 8 4 7 1 8

2 . 8 5 6 2 8

1 . 4 4 7 2 4 1 3

3 . 3 8 3 4 2 6

2 . 6 2 9 1 7

1 . 2 3 0 3 54

2 . 5 4 9 1 0 5

2 . 0 2 1 4 8 2 9

3 . 6 8 4 1 0 3 0

3 . 0 1 3 1 2 4 0

3 . 0 9 3 4 06

2 . 6 0 9 2494

3 . 3 9 7

1 9 3

194 CHAPTER 5


BIGRAM POSITION 1ST

I1 0 0.000

IK 0 0.000

IL 0 0.000

IM 131 2.117

IN 228 2.358

I0 8 .903

IP 0 0.000

IR 47 1.672

IS 169 2.228

IT 106 2.025

IV 17 1.230

IX 0 0.000

I2 0 0.000

JA 142 2.152

JE 86 1.934

JI 11 1.041

JO 155 2.190

JU 131 2.117

KA 27 1.431

KE 21 1.322

KI 68

2N D

0 0.000

82 1.914

535 2.728

438 2.641

1401 3.146

24 1.380

26 1.415

1914 3.282

2 26 2.354

264 2.422

1053 3.022

196 2.292

24 1.380

0 0.000

0 0.000

0 0.000

0 0.000

0 0.000

0 0.000

0 0.000

82 1.833 1.914

3RD

0 0.000

20 1.301

2279 3.358

91 1.959

3331 3.523

255 2.407

92 1.964

325 2.512

305 2.484

1217 3.085 174

2.241

0 0.000

34 1.531

0 0.000

0 0.000

0 0.000

291 2.464

0 0.000

0 0.000

1151 3.061

5 .699

4TH

4 .602

0 0.000

722 2.859

98 1.991

1090 3.037

156 2.193

34 1.531

2752 3.440

447 2.650

339 2.530

0 0.000

30 1.477

0 0.000

0 0.000

0 0.000

0 0.000

0 0.000

0 0.000

0 0.000

3 58 2.554

0 0.000

SUM

4 .602 102

2.009

3536 3.549

7 58 2.880

6050 3.782

443 2.646

152 2.182

5038 3.702

1147 3.060 1926 3.285

1244 3.095

226 2.354

58 1.763

142 2.152

86 1.934

11 1.041

446 2.649

131 2.117

27 1.431

1530 3.185

155 2.190

APPENDIX 5 . 2


BIGRAM POSITION 1ST

KL 0 0 . 0 0 0

K N 490 2 .690

KO 1 2 1 . 0 7 9

KS 0 0 .000

K U 0 0 . 0 0 0

K Y 0 0 .000

LA 1 1 1 9 3.049

L B 0 0 . 0 0 0

LC 0 0 .000

L D 0 0 . 0 0 0

LE 1 0 6 3 3 . 0 2 7

LF 0 0 .000

LG 0 0 . 0 0 0

LH 0 0 . 0 0 0

L I 9 5 8 2 . 9 8 1

L K 0 0.0063

L L 1 0 1 . 0 0 0

LM 0 0 .000

L O 8 7 8 2 . 9 4 3

LP 0 0 * 000

LS 0 0 .000

2N D

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

3 . 4 7 7

0 0 . 0 0 0

1 9 7 5 3 . 2 9 6

1 6 1 . 2 0 4

5 . 6 9 9

1 0 8 2 . 0 3 3

574 2 . 7 5 9

0 0 . 0 0 0

0 0 . 0 0 0

0 0.6300

2 8 8 2 . 4 5 9

0 0 . 0 0 0

1 2 1 2 . 0 8 3

6 - 7 7 8 1 4 6 1

3 . 1 6 5 0

0 . 0 0 0 4

.602

3RD

8 . 9 0 3

0 0 . 0 0 0

0 0 . 0 0 0

0 0 .000

0 0 . 0 0 0

1 8 1 . 2 5 5

1 1 3 2 . 0 5 3

3 .477

0 0 . 0 0 0

4 9 1 . 6 9 0

7 3 1 2 . 8 6 4

8 . 9 0 3

5 . 6 9 9

5 . 6 9 9

2 3 2 2 . 3 6 5

6 5 1 . 8 1 3

789 2 . 8 9 7

39 1 . 5 9 1

405 2 . 6 0 7

5 3 1 . 7 2 4

38 1 . 5 8 0

4TH SUM

0 8 0 . 0 0 0 . 9 0 3

0 490 0 . 0 0 0 2 . 6 9 0

0 1 2 0 . 0 0 0 1 . 0 7 9

8 1 2 8 1 2 2 .910 2 . 9 1 0

0 3 0 . 0 0 0 . 4 7 7

7 2 9 0 1 . 8 5 7 1 . 9 5 4

2 8 3 2 3 5 1 . 4 4 7 3 . 5 1 0

0 1 9 0 . 0 0 0 1 . 2 7 9

0 5 0 . 0 0 0 . 6 9 9

5 7 1 5 5 8 7 2 3 . 7 5 7 3 . 7 6 9

1 8 3 7 4 2 0 5 3 . 2 6 4 3 .624

1 2 2 0 1 . 0 7 9 1 . 3 0 1

0 5 0 . 0 0 0 . 6 9 9

0 5 0 . 0 0 0 . 6 9 9

0 1 4 7 8 0 . 0 0 0 3 . 1 7 0

3 6 8 . 4 7 7 1 . 8 3 3 1 8 0 6 2 7 2 6

3 . 2 5 7 3 . 4 3 6 19 6 4

1 . 2 7 9 1 . 8 0 6 1 0 2 7 5 4

1 . 0 0 0 3 . 4 4 0 4 5 7

. 6 0 2 1 . 7 5 6 1 0 0 6 1 0 4 8

3 . 0 0 3 3 . 0 2 0

1 9 5

1 9 6 CHAPTER 5


BIGRAM POSITION 1ST

LT 0 0 . 0 0 0

LU 111 2 . 0 4 5

L V 0 0 .000

LY 4 8 1 . 6 8 1

MA 9 7 8 2 .990

MB 0 0 .000

ME 6 5 0 2 . 8 1 3

M I 1 1 0 9 3 . 0 4 5

ML 0 0 .000

M M 0 0 . 0 0 0

MN 0 0 . 0 0 0

MO 1 2 3 6 3 . 0 9 2

MP 0 0 . 0 0 0

YS 0 0 . 0 0 0

MU 2 4 1 2 . 3 8 2

MY 6 . 7 7 8

N A 2 8 1 2 . 4 4 9

NC 0 0 .000

ND 0 0 .000

N E 1 0 2 5 3 . 0 1 1

NG 0 0 . 0 0 0

2ND

24 1 . 3 8 0

1 9 1 2 . 2 8 1

6 . 7 7 8

4 . 6 0 2

6 9 3 2 . 8 4 1

0 0 .000

3 4 1 . 5 3 1

1 1 5 2 . 0 6 1

0 0 . 0 0 0

0 0 .000

0 0 . 0 0 0

416 2 .619

9 6 1 . 9 8 2

0 0 .000

3 . 4 7 7

0 0 .000

6 1 1 . 7 8 5

6 2 1 . 7 9 2

9 2 2 2 . 9 6 5

1 4 4 2 . 1 5 8

1 6 2 2 .210

3RD

4 0 1 . 6 0 2

200 2 . 3 0 1

2 6 1 . 4 1 5

0 0 . 0 0 0

5 8 1 2 .764

44 1 . 6 4 3

1 1 6 2 3 . 0 6 5

1 0 5 2 . 0 2 1

1 2 1 . 0 7 9

46 1 . 6 6 3

6 . 7 7 8

1 0 7 2 . 0 2 9

3 6 1 . 5 5 6

0 0 .000

4 . 6 0 2

0 0 . 0 0 0

1 7 8 2 .250

9 6 6 2 . 9 8 5

7 5 1 2 . 8 7 6

8 6 1 2 . 9 3 5

370 2 . 5 6 8

4TH

2 1 3 2 .328

0 0 .000

0 0 . 0 0 0

1 0 5 5 3 . 0 2 3

6 7 1 . 8 2 6

27 1 . 4 3 1

2 8 3 2 .452

22 1 . 3 4 2

0 0 .000

0 0 .000

0 0 . 0 0 0

0 0 .000

27 1 . 4 3 1

1 0 9 8 3 . 0 4 1

0 0 .000

1 1 7 2 . 0 6 8

1 0 1 2 . 0 0 4

0 0 .000

1 3 3 1 3 .124

607 2 .783

3346 3 .525

SUM

2 7 1 2 . 4 4 2

5 0 2 2 . 7 0 1

3 2 1 . 5 0 5

1 1 0 7 3 . 0 4 4

2 3 1 9 3 . 3 6 5

7 1 1 . 8 5 1

2 1 2 9 3 . 3 2 8

1 3 5 1 3 . 1 3 1

1 2 1 . 0 7 9

4 6 1 . 6 6 3

6 . 7 7 8 1 7 5 9

3 . 2 4 5 1 5 9

2 . 2 0 1 1 0 9 8

3 . 0 4 1 2 4 8

2 . 3 9 4 1 2 3

2 . 0 9 0 6 2 1

2 . 7 9 3 1 0 2 8

3 .012 3004

3 . 4 7 8 2637

3 . 4 2 1 3 8 7 8

3 . 5 8 9

APPENDIX 5 .2


BIGRAM POSITION 1ST

NI 4 6 7 2 . 6 6 9

NJ 0 0 . 0 0 0

NK 0 0 . 0 0 0

NL 0 0 . 0 0 0

NN 0 0 . 0 0 0

NO 5 4 6 2 . 7 3 7

NP 0 0 . 0 0 0

NR 0 0 . 0 0 0

NS 0 0 . 0 0 0

N T 0 0 . 0 0 0

NU 1 7 1 . 2 3 0

NX 0 0 . 0 0 0

NY 0 0 . 0 0 0

OA 3 . 4 7 7

OB 0 0 .000

oc 7 7 1 . 8 8 6

OD 1 7 1 . 2 3 0

OE 0 0 . 0 0 0

OF 4 4 8 2 . 6 5 1

OG 0 0 . 0 0 0

OH 0 0 . 0 0 0

2 N D

4 4 1 2 .644

4 4 1 . 6 4 3

8 . 9 0 3

4 . 6 0 2

5 8 1 . 7 6 3

3 7 0 2 . 5 6 8

2 0 1 . 3 0 1

0 0 . 0 0 0

3 8 1 . 5 8 0

5 6 5 2 . 7 5 2

0 0 .000

0 0 .000

0 0 . 0 0 0

5 7 3 2 . 7 5 8

1 0 8 2 .033

4 0 0 2 . 6 0 2

4 1 9 2 . 6 2 2

1 1 4 2 . 0 5 7

5 . 5 9 9

6 1 1 . 7 8 5

9 . 9 5 4

3 R D

5 3 1 . 7 2 4

0 0 . 0 0 0

1 1 3 2 . 0 5 3

0 0 . 0 0 0

1 1 3 2 . 0 5 3

1 5 2 2 .182

0 0 .000

9 9 1 . 9 9 6

34fJ 2 . 5 3 1

3 1 3 2 . 4 9 6

2 2 1 . 3 4 2

0 0 . 0 0 0

0 0 . 0 0 0

1 0 5 2. fJ21

2 3 1 . 3 6 2

2 9 5 2 . 4 7 0

2 5 9 2 .413

4 4 1 . 6 4 3

1 5 1 . 1 7 6

0 0 . 0 0 0

0 0 . 0 0 0

4TH

0 0 . 0 0 0

0 0 . 0 0 0

7 1 1 2 . 8 5 2

0 0 . 0 0 0

6

3 8 1 . 5 8 0

0 0 . 0 0 0

0 0 . 0 0 0

8 1 9 2 . 9 1 3

1 4 0 3 3 . 1 4 7

0 0 . 0 0 0

9 . 9 5 4

1 4 2 2 . 1 5 2

0 0 . 0 0 0

0 0 . 0 0 0

3 . 4 7 7

3 6 1 2 . 5 5 8

11 1 . 0 4 1

4 5 1 . 6 5 3

0 0 . 0 0 0

0 0 . 0 0 0

. 7 i a

SUM

9 6 1 2 . 9 8 3

4 4 1 . 6 4 3

8 3 2 2 . 9 2 0

4 . 6 0 2

1 7 7 2 . 2 4 8

1 1 0 6 3 . 0 4 4

2 0 1 . 3 0 1

9 9 1 . 9 9 6

1 1 9 7 3 . 0 7 8

2 2 8 1 3 . 3 5 8

3 9 1 . 5 9 1

9 .9 5 4

1 4 2 2 . 1 5 2

6 8 1 2 . 8 3 3

1 3 1 2 . 1 1 7

7 7 5 2 . 8 8 9

1 0 5 6 3 . 0 2 4

1 6 9 2 . 2 2 8

5 1 3 2 . 7 1 0

6 1 1 . 7 8 5

9 . 9 5 4

1 9 7

1 9 8 CHAPTER 5


BIGRAM POSITION 1ST

01 3 . 4 7 7

OK 0 0 .000

O L 9 8 1 . 9 9 1

OM 0 0 . 0 0 0

ON 5 3 1 . 7 2 4

00 0 0 .000

OP 6 3 1 . 7 9 9

OR 404 2 . 6 0 6

0s 9 . 9 5 4

OT 1 7 0 2 3 . 2 3 1

O U 1 0 5 2 . 0 2 1

ov 11 1 . 0 4 1

OW 7 1 1 . 8 5 1

ox 0 0 . 0 0 0

OY 0 0 . 0 0 0

0 2 0 0 .000

PA 8 3 8 2 . 9 2 3

PE 3 1 8 2 . 5 0 2

PH 1 4 3 2 . 1 5 5

P I 297 2 . 4 7 3

PL 1 1 1 7 3 . 0 4 8

2ND

1 3 0 6 3 . 1 1 6

50 1 . 6 9 9

4 8 9 2 .689

7 7 5 2 . 8 8 9

8 2 0 2 . 9 1 4

6 6 3 2 . 8 2 2

1 0 9 2 . 0 3 7

2 7 2 6 3 .436

2 7 9 2 . 4 4 6

6 6 3 2 . 8 2 2

7 6 4 9 3 .884

500 2 . 6 9 9

5 8 1 2 . 7 6 4

1 4 1 . 1 4 6

94 1 . 9 7 3

5 7 1 . 7 5 6

3 0 1 2 .479

446 2 . 6 4 9

0 0 . 0 0 0

7 1 1 . 8 5 1

3 0 1 . 4 7 7

3 RD

6 9 1 . 8 3 9

4 1 1 2 . 6 1 4

3 7 3 2 . 5 7 2

9 9 1 . 9 9 6

1 4 7 5 3 .169

7 2 4 2 . 8 6 0

1 2 9 2 . 1 1 1

7 59 2 .880

1 6 1 9 3 . 2 0 9

4 29 2 . 6 3 2

2 3 4 2 3 . 3 7 0

4 4 9 2 . 6 5 2

972 2 . 9 8 8

7 . 8 4 5

1 0 1 . 0 0 0

4 . 6 0 2

52 1 . 7 1 6

5 0 1 2 . 7 0 0

0 0 . 0 0 0

7 2 1 . 8 5 7

1 4 6 2 . 1 6 4

4TH

0 0 . 0 0 0

6 3 1 . 7 9 9

8 . 9 0 3

4 6 1 . 6 6 3

3 9 6 2 . 5 9 8

3 . 4 7 7

2 5 1 . 3 9 8

1 2 4 3 3 . 0 9 4

2 8 1 . 4 4 7

8 8 1 . 9 4 4

0 0 . 0 0 0

9 . 9 5 4

309 2 . 4 9 0

0 0 .000

44 1 . 6 4 3

0 0 .000

5 . 6 9 9

1 3 4 2 . 1 2 7

3 9 1 . 5 9 1

0 0 .000

0 0 .000

SUM

1 3 7 8 3 . 1 3 9

524 2 . 7 1 9

9 6 8 2 . 9 8 6

9 2 0 2 . 9 6 4

2 7 4 4 3 . 4 3 8

1 3 9 0 3 . 1 4 3

3 2 6 2 . 5 1 3

5 1 3 2 3 . 7 1 0

1 9 3 5 3 . 2 8 7

2 8 8 2 3 . 4 6 0 1 0 0 9 6 4 . 0 0 4

9 6 9 2 . 9 8 6

1 9 3 3 3 . 2 8 6

2 1 1 . 3 2 2

1 4 8 2 . 1 7 0

6 1 1 . 7 8 5

1 1 9 6 3 . 0 7 8

1 3 9 9 3 . 1 4 6

1 8 2 2 . 2 6 0

440 2 . 6 4 3

1 2 9 3 3 . 1 1 2

APPENDIX 5.2



PO 1 0 2 8 3 . 0 1 2

PP 0 0 .000

PR 6 1 5 2 .789

PS 0 0 .000

PT 0 0 . 0 0 0

PU 6 2 1 . 7 9 2

PY 0 0 . 0 0 0

QU 5 1 5 2 . 7 1 2

R A 7 2 5 2 .860

R B 0 0 . 0 0 0

RC 0 0 . 0 0 0

RD 0 0 . 0 0 0

R E 486 2 .687

RF 0 0 . 0 0 0

RG 0 0 . 0 0 0

RH 1 0 8 2 . 0 3 3

R I 9 6 9 2 . 9 8 6

RK 0 0 . 0 0 0

R L 0 0 . 0 0 0

RM 0 0 . 0 0 0

R N 0 0 . 0 0 0

2ND

1 5 1 2 .179

1 3 7 2 . 1 3 7

9 8 1 . 9 9 1

1 4 1 . 1 4 6

4 . 6 0 2

3 . 4 7 7

0 0 . 0 0 0

1 1 5 2 . 0 6 1

1 2 7 8 3 .107

5 8 1 . 7 6 3

0 0 . 0 0 0

376 2 . 5 7 5

1 9 0 6 3 . 2 8 0

0 0 .000

8 4 1 . 9 2 4

0 0 .000

1 5 0 8 3 . 1 7 8

0 0 . 0 0 0

0 0 . 0 0 0

6 4 1 . 8 0 6

2 3 1 . 3 6 2

3RD

2 5 1 . 3 9 8

1 0 3 2 . 0 1 3

0 0 .000

1 0 1 . 0 0 0

1 1 7 2 . 0 6 8

20 1 . 3 0 1

0 0 . 0 0 0

0 0 . 0 0 0

292 2 . 4 6 5

1 7 1 . 2 3 0

419 2 . 6 2 2

482 2 . 6 8 3

1 0 5 8 3 . 0 2 4

0 0 . 0 0 0

404 2 . 6 0 6

0 0 .000

2 5 5 2 .407

1 9 9 2 . 2 9 9

1 3 1 9 3 . 1 2 0

408 2 . 6 1 1

9 0 1 . 9 5 4

4TH

4 . 6 0 2

0 0 . 0 0 0

0 0 . 0 0 0

4 9 1 2 . 6 9 1

1 0 8 2 . 0 3 3

0 0 . 0 0 0

9 8 1 . 9 9 1

0 0 . 0 0 0

1 2 3 2 . 0 9 0

0 0 . 0 0 0

0 0 . 0 0 0

8 2 4 2 . 9 1 6

4 1 5 7 3 . 6 1 9

7 . 8 4 5

0 0 . 0 0 0

0 0 . 0 0 0

1 6 1 . 2 0 4

9 1 1 . 9 5 9

1 2 1 . 0 7 9

7 1 1 . 8 5 1

1 1 6 2 .064

SUM

1 2 0 8 3 . 0 8 2

240 2 . 3 8 0

7 1 3 2 . 8 5 3

5 1 5 2 . 7 1 2

2 2 9 2 . 3 6 0

8 5 1 . 9 2 9

9 8 1 . 9 9 1

6 3 0 2 . 7 9 9

2 4 1 8 3 . 3 8 3

7 5 1 . 8 7 5

4 1 9 2 . 6 2 2

1 6 8 2 3 . 2 2 6

7 6 0 7 3 . 8 8 1

7 . 8 4 5

4 8 8 2 . 6 8 8

1 0 8 2 . 0 3 3

2 7 4 8 3 . 4 3 9

290 2 . 4 6 2

1 3 3 1 3 . 1 2 4

5 4 3 2 . 7 3 5

2 29 2 . 3 6 0

1 9 9

200 CHAPTER 5


BIGRAM POSITION 1ST

RO 548 2 .739

RP 0 0 .000

RR 0 0 .000

RS 0 0 .000

RT 0 0 .000

RU 200 2 .301

RV 0 0 .000

RY 0 0 .000

SA 375 2 .574

SC 370 2 .568

SE 9 4 3 2 .975

SH 1 6 5 5 3 .219

SI 1 0 2 5 3 .011

SK 8 5 1 .929

SL 254 2 .405

SM 766 2 .884

SN 6 1 1 . 7 8 5

S O 750

SP 8 9 6 2 .952

SQ 25 1 . 3 9 8

SS 0 0 .000

2 .875

2ND

1 9 2 6 3 .285

0 0 .000

6 4 1 . 8 0 6

0 0 .000

0 0 .000

512 2 .709

0 0 .000

1 9 1 .279

24 1 . 3 8 0

9 . 954

6 . 7 7 8

6 . 778

222 2 .346

398 2 .600

7 . 8 4 5

0 0 .000

0 0 .000

0 0 .000

0 0 .000

0 0 .000

3RD 4TH

1 3 1 1 1 5 2 .117 2 .061

1 0 9 7 2 2 .037 1 . 8 5 7

362 0 2 .559 0 .000

1 7 1 8 1 4 1 6 3 .235 3 .151

1 0 2 8 997 3 .012 2 .999

6 1 5 1 . 7 8 5 .699

1 7 1 0 2 .233 0 .000

0 1254 0 .000 3 .098

5 5 6 1 . 7 4 0 .778

7 0 . 8 4 5 0 .000

519 4720 2 . 7 1 5 3 .674

0 289 0 .000 2 .461

700 0 2 .845 0 .000

5 1 7 1 . 7 0 8 .845

6 0 . 778 0 .000

0 3 0 .000 .477

0 0 0 .000 0 .000

3 1 7 1 . 4 9 1 . 8 4 5

5 2 5 .699 1 . 3 9 8

0 0 0 .000 0 .000

1 9 1 1 7 787 2 .281 1 .230 2 .896

SUM

2720 3 . 4 3 5

1 8 1 2 .258

4 26 2 .629

3134 3 .496

2025 3 .306

7 7 8 2 .891

1 7 1 2 .233

1 2 7 3 3 . 1 0 5

460 2 . 6 6 3

386 2 .587

6 1 8 8 3 .792

1 9 5 0 3 .290

1 9 4 7 3 .289

541 2 .733

267 2 .427

769 2 .886

6 1 1 . 7 8 5

788 2 .897

926 2 .967

2 5 1 .398

9 9 5 2 .998

A P P E N D I X 5.2 2 0 1

B I G R A M F R E Q U E N C I E S F O R WORDS O F L E T T E R LENGTH 5

B I G R A M P O S I T I O N 1ST 2 N D 3 R D 4 T H SUM

ST

su

sw

S Y

T A

T C

T D

T E

T H

T I

T L

T O

3855 3 .586

1 5 6 2.193

3 0 6 2 .486

4 .602

8 0 9 2.908

0 0.000

0 0 .000

6 2 4 2 .795

9 6 6 9 3.985

517 2 .713

0 0.000

8 7 0 2 .940

0 499 0 .000 2.698

9 6 216 1.982 2.334

0 0 0 .000 0 .000

0 0 0.000 0 .000

1 5 5 1 362 3 . 1 9 1 2.559

0 2 68 0 .000 2.428

0 3 0.000 .477

372 3129 2 .571 3.495

1 7 1 3 44 3.234 1 .643

8 56 5 9 1 2.932 2.772

1 2 8 1 1.079 1.908

7 6 4 9 8 2.883 1 . 9 9 1

2 2 3 6 3.349

0 0.000

0 0.000

28 1.447

5 0 1 . 6 9 9

0 0 . 0 0 0

0 0 .000

2 1 0 4 3.323

2068 3 .316

0 0.000

0 0 . 0 0 0

3 6 1 . 5 5 6

6 5 9 0 3 .819

4 6 8 2 .670

3 0 6 2.486

3 2 1 . 5 0 5

2772 3.443

268 2.428

3 - 4 7 7

6 2 2 9 3.794

1 3 4 9 4 4 .130

1 9 6 4 3 .293

93 1 .968

1 7 6 8 3 .247

T R 1 2 1 2 6 0 8 5 0 1 3 5 7 3 .084 1 .778 1.929 0 . 0 0 0 3.133

TS 0 0 0 1 1 7 3 1 1 7 3 0 .080 0.000 0.000 3 .069 3 .069

TT 0 29 58 2 9 1 1 6 0 .000 1 . 4 6 2 1 . 7 6 3 1 .462 2.064

T U 1 0 9 3 0 1 8 0 4 1 8 2.037 2.479 .903 0 .000 2 . 6 2 1

TW 1 0 9 0 0 0 1 0 9 2 .037 0.000 0 .000 0 . 0 Q 0 2 .037

T Y 1 2 4 9 8 0 5 9 1 8 1 3 2.093 1 . 9 9 1 0.00B 2.772 2 .910

T Z 0 0 0 3 3 0 . 0 0 0 0 .000 0 .000 .477 .477

UA 0 5 1 2 1 1 0 2 6 2 0 .000 1 . 7 0 8 2.324 0 .000 2 .418

UB 0 6 2 1 3 8 9 2 0 9 0.000 1.792 2.140 . 9 5 4 2 .320

202 C H A P T E R 5


BIGRAM P O S I T I O N 1 S T

uc 0 0.000

UD 0 0.000

UE 0 0 .000

UF 0 0.000

UG 0 0.000

U I 0 0 .000

U L 5 .699

U M 0 0.000

UN 1 5 8 8 3 . 2 0 1

00 0 0 .000

U P 8 6 1 . 9 3 4

UR 8 5 1 .929

US 2 6 1 2.417

UT 1 3 1.114

u x 0 0 .000

u z 0 0 .000

VA '262 2.418

V E 7 0 1 . 8 4 5

V I 294 2.468

VO 3 0 9 2.490

VY 3 .477

2N D

4 9 1.690

1 1 0 2 . 0 4 1

1 6 1 2.207

0 0.000

1 0 8 2.033

7 7 3 2 .888

3 0 1 2 .479

384 2.584

283 2.452

2 1 1 . 3 2 2

28 1 . 4 4 7

3 5 1 2 .545

304 2 .483

6 5 1 . 8 1 3

0 0.000

7 .845

1 4 1.146

583 2 .766

9 .954

8 1 1.908

0 0.000

3 R D

2 2 5 2.352

268 2.428

6 6 1.820

4 4 1 .643

1 7 6 2.246

1 2 9 2 . 1 1 1

4 4 4 2 3.648

57 1 .756

1 5 4 1 3 .188

0 0.000

0 0 .000

463 2.666

9 0 2 2 .955

6 1 6 2.790

0 0.000

0 0.000

5 1 1.708

2 5 7 0 3 .410

2 77 2.442

8 1 1 . 9 0 8

0 0.000

4 T H

0 0.000

1 0 8 2.033

4 2 5 2.628

0 0.000

0 0.000

0 0 .000

1 7 1.230

3 7 1 .568

5 1 1 . 7 0 8

0 0.000

402 2.604

5 6 1 . 7 4 8

1 5 0 2.176

1 8 7 6 3.273

8 .903

0 0.000

0 0.000

1 1 2 5 3 . 0 5 1

0 0.000

0 0 .000

1 1 4 2.057

SUM

274 2.438

4 8 6 2.687

6 5 2 2.814

4 4 1 .643

284 2 .453

9 0 2 2 .955

4 7 6 5 3 .678

478 2.679

3463 3 .539

2 1 1 .322

516 2.713

9 5 5 2.980

1 6 1 7 3.209

2 5 7 0 3.410

8 .903

7 . 8 4 5

327 2.515

4 3 4 8 3.638

580 2 .763

2 .673

1 1 7 2 .068

4 i i

APPENDIX 5 . 2



WA 9 6 1 2 . 9 8 3

WD 0 0 . 0 0 0

WE 2 0 1 2 . 3 0 3

WF 0 0 .000

WH 6 1 8 4 3 . 7 9 1

W I 207 2 . 3 1 6

WL 0 0 . 0 0 0

WN 0 0 . 0 0 0

WO 4632 3 . 6 6 6

WR 446 2 . 6 4 9

ws 0 0 . 0 0 0

wu 0 0 . 0 0 0

WY 3 . 4 7 7

X A 0 0 . 0 0 0

X E 0 0 . 0 0 0

X I 0 0 . 0 0 0

xo 0 0 . 0 0 0

XT 0 0 . 0 0 0

X Y 0 0 . 0 0 0

Y A 6 8 1 . 8 3 3

Y B 0 0 . 0 0 0

2ND

1 6 5 2 . 2 1 7

0 0 .000

1 7 2 2 .236

1 7 1 . 2 3 0

0 0 . 0 0 0

1 7 8 2 .250

0 0 .000

6 7 1 . 8 2 6

3 5 1 . 5 4 4

0 0 . 0 0 0

0 0 . 0 0 0

48 1 . 6 8 1

0 0 .000

27 1 . 4 3 1

11 1 . 0 4 1

6 3 1 . 7 9 9

0 0 . 0 0 0

50 1 . 6 9 9

0 0 . 0 0 0

3 . 4 7 7

0 0 , 0 0 0

3RD

0 0 . 0 0 0

7 . 8 4 5

569 2 . 7 5 5

0 0 .000

0 0 . 0 0 0

6 8 1 . 8 3 3

3 8 1 . 5 8 0

7 3 1 . 8 6 3

0 0 .000

0 0 .000

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

7 4 1 . 8 6 9

2 1 1 2 . 3 2 4

3 . 4 7 7

2 5 1 . 3 9 8

5 1 1 . 7 0 8

0 0 .000

7 8 1 . 8 9 2

1 3 4 2 . 1 2 7

4TH

0 0 . 0 0 0

53 1 . 7 2 4

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

1 5 1 . 1 7 6

7 3 8 2 .868

0 0 . 0 0 0

0 0 . 0 0 0

3 1 1 2 . 4 9 3

0 0 . 0 0 0

4 . 6 0 2

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

7 .845

0 0 . 0 0 0

0 0 . 0 0 0

SUM

1 1 2 6 3 . 0 5 2

6 0 1 . 7 7 8

9 4 2 2 . 9 7 4

1 7 1 . 2 3 0

6 1 8 4 3 . 7 9 1

4 5 3 2 . 6 5 6

5 3 1 . 7 2 4

8 7 8 2 . 9 4 3

4667 3 . 6 6 9

446 2 . 6 4 9

3 1 1 2 . 4 9 3

4 8 1 . 6 8 1

7 . 8 4 5 101

2 .004 2 2 2

2 . 3 4 6 6 6

1 . 8 2 0 2 5

1 . 3 9 8 1 0 1

2 . 0 0 4 7

. 8 4 5 1 4 9

2 . 1 7 3 1 3 4

2 . 1 2 7

2 0 3

204 CHAPTER 5


BIGRAM POSITION 1ST

Y C 0 0 . 0 0 0

Y D 0 0 .000

Y E 9 5 2 2 . 9 7 9

Y I 3 5 1 . 5 4 4

Y L 0 0 . 0 0 0

YM 0 0 . 0 0 0

Y N 0 0 .000

Y O 492 2 .692

YP 0 0 .000

Y R 0 0 .000

YS 0 0 . 0 0 0

YT 0 0 . 0 0 0

Z A 0 0 . 0 0 0

Z E 0 0 . 0 0 0

Z I 0 0 . 0 0 0

Z O 3 . 4 7 7

Z Y 0 0 . 0 0 0

Z Z 0 0 . 0 0 0

2N D

24 1 . 3 8 0

0 0 . 0 0 0

0 0 . 0 0 0

18 1 . 8 9 2

11 1 . 0 4 1

6 . 7 7 8

0 0.000

0 0 .000

1 2 3 2 . 0 9 0

3 6 1 . 5 5 6

0 0 . 0 0 0

6 . 7 7 8

0 0 . 0 0 0

0 0 .000

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

3RD

2 1 1 . 3 2 2

0 0 . 0 0 0

3 5 1 . 5 4 4

5 . 6 9 9

1 1 3 2 . 0 5 3

3 . 4 7 7

1 2 1 . 0 7 9

3 8 1 . 5 8 0

1 4 1 . 1 4 6

0 0 . 0 0 0

4 . 6 0 2

0 0 . 0 0 0

0 0 . 0 0 0

8 4 1 . 9 2 4

1 2 1 . 0 7 9

1 5 1 . 1 7 6

0 0 . 0 0 0

1 5 1 . 1 7 6

4TH

0 0 .000

1 0 1 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

18 1 . 2 5 5

0 0 . 0 0 0

0 0 . 0 0 0

7 4 1 . 8 6 9

0 0 . 0 0 0

3 . 4 7 7

4 8 1 . 6 8 1

0 0 . 0 0 8

0 0 . 0 0 0

4 6 1 . 6 6 3

0 0 . 0 0 0

SUM

4 5 1 . 6 5 3

1 0 1 . 0 0 0

987 2 . 9 9 4

1 1 8 2 .012

1 2 4 2 . 0 9 3

9 . 9 5 4

1 2 1 . 0 7 9

5 4 8 2 . 7 3 9

1 3 7 2 . 1 3 7

3 6 1 . 5 5 6

7 8 1 . 8 9 2

6 . 7 7 8

3 . 4 1 7

1 3 2 2 . 1 2 1

1 2 1 . 0 7 9

18 1 . 2 5 5

4 6 1 . 6 6 3

1 5 1 . 1 7 6

APPENDIX 5 . 2



AA 0 0 . 0 0 0

A B 1 7 0 2 . 2 3 0

AC 9 6 7 2 . 9 8 5

AD 1 4 1 2 . 1 4 9

A E 8 . 9 0 3

AF 232 2 . 3 6 5

AG 1 9 2 2 . 2 8 3

AH 0 0 . 0 0 0

A 1 1 2 1 . 0 7 9

A J 0 0 . 0 0 0

AK 0 0 . 0 0 0

A L 1 0 9 4 3 . 0 3 9

AM 2 0 2 2 . 3 0 5

A N 604 2 . 7 8 1

AP 1 8 5 2 . 2 6 7

AQ 0 0 . 0 0 0

A R 9 0 6 2 .957

AS 344 2 . 5 3 7

AT 2 5 3 2 . 4 0 3

AU 1 3 9 2 . 1 4 3

AV 49 1 . 6 9 0

2N D

0 0 . 0 0 0

1 2 2 2 . 0 8 6

406 2 . 6 0 9

1 3 1 2 . 1 1 7

6 . 7 7 8

6 4 1 . 8 0 6

1 0 2 2 . 0 0 9

0 0 . 0 0 0

494 2 . 6 9 4

3 . 4 7 7

470 2 .672

1 4 3 0 3 . 1 5 5

7 4 3 2 . 8 7 1

1 3 7 7 3 . 1 3 9

1 6 0 2 . 2 0 4

0 0 . 0 0 0

1 8 3 0 3 .262

7 1 5 2 . 8 5 4

1 9 5 0 3 .290

3 6 8 2 . 5 6 6

3 8 8 2 . 5 8 9

3RD

0 0 .000

1 4 0 2 .146

332 2 . 5 2 1

3 6 3 2 .560

0 0 . 0 0 0

11 1 . 0 4 1

2 2 1 2 . 3 4 4

22 1 . 3 4 2

324 2 . 5 1 1

0 0 . 0 0 0

1 0 3 2 . 0 1 3

472 2 . 6 7 4

8 5 1 . 9 2 9

8 9 5 2 . 9 5 2

1 4 8 2 . 1 7 0

6 . 7 7 8

8 6 5 2 . 9 3 7

4 37 2 , 6 4 0

9 67 2 . 9 8 5

9 6 1 . 9 8 2

2 5 7 2 . 4 1 0

4TH

7 . 8 4 5

0 0 . 0 0 0

277 2 . 4 4 2

1 6 7 2 . 2 2 3

1 5 1 . 1 7 6

0 0 .000

1 5 6 2 .193

0 0 . 0 0 0

462 2 . 6 6 5

0 0 . 0 0 0

4 6 1 . 6 6 3

2 7 0 2 . 4 3 1

3 1 6 2 .500

4 9 1 2 . 6 9 1

7 1 1 . 8 5 1

0 0 . 0 0 0

9 3 3 2 . 9 7 0

151 2 . 1 7 9

370 2 . 5 6 8

0 0 . 0 0 0

1 3 1 . 1 1 4

5TH

0 0 . 0 0 0

0 0 . 0 0 0

4 . 6 0 2

1 8 5 2 . 2 6 7

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

1 0 1 . 0 0 0

1 5 5 8 3 . 1 9 3

8 3 1 . 9 1 9

3 1 0 2 .491

4 . 6 0 2

0 0 . 0 0 0

2 7 8 2 . 4 4 4

220 2 . 3 4 2

1 9 3 2 . 2 8 6

57 1 . 7 5 6

0 fl.000

SUM

7 . 8 4 5

432 2 . 6 3 5

1 9 8 6 3 . 2 9 8

987 2 .994

29 1 . 4 6 2

3 07 2 .487

6 7 1 2 . 8 2 7

22 1 . 3 4 2

1 2 9 2 3 . 1 1 1

3 . 4 7 7

6 2 9 2 .799

4 8 2 4 3 . 6 8 3

1 4 2 9 3 .155

3 6 7 7 3 .565

568 2.754

6 . 7 7 8 4 8 1 2

3 . 6 8 2 1 8 6 7

3 . 2 7 1 3 7 3 3

3 . 5 7 2 660

2 . 8 2 0 7 0 7

2 . 8 4 9

2 0 5

2 06 CHAPTER 5


BIGRAM POSITION 1ST

AW 3 1 1 . 4 9 1

AX 0 0 . 0 0 0

AY 0 0 . 0 0 0

AZ 0 0 .000

BA 376 2 . 5 7 5

BB 0 0 . 0 0 0

B E 3 0 2 2 3 .480

B I 1 2 1 2 . 0 8 3

B J 0 0 .000

BL 1 0 1 2 . 0 0 4

BM 0 0 . 0 0 0

BO 5 3 5 2 .728

BR 5 3 3 2 .727

BS 0 0 . 0 0 0

BT 0 0 . 0 0 0

BU 4 2 5 2 .628

BW 0 0 .000

BY 3 . 4 7 7

CA 1 4 6 8 3 . 1 5 7

cc 0 0 .000

CE 320 2 . 5 0 5

2N D

6 2 1 . 7 9 2

9 . 9 5 4

200 2 . 3 0 1

2 7 1 . 4 3 1

0 0 . 0 0 0

0 0 . 0 0 0

7 . 8 4 5

0 0.000

6 8 1 . 8 3 3

3 . 4 7 7

0 0 . 0 0 0

2 5 1 . 3 9 8

6 9 1 . 8 3 9

58 1 . 7 6 3

4 2 1 . 6 2 3

1 2 1 . 0 7 9

0 0 .000

0 0 . 0 0 0

3 6 1 . 5 5 6

1 6 7 2 . 2 2 3

44 1 . 6 4 3

3RD

11 1 . 0 4 1

3 . 4 7 7

2 8 2 2 . 4 5 0

4 1 1 . 6 1 3

5 3 1 . 7 2 4

8 5 1 . 9 2 9

1 5 5 2 .190

1 0 6 2 . 0 2 5

0 0 . 0 0 0

490 2 .690

1 8 1 . 2 5 5

92 1 . 9 6 4

3 3 1 . 5 1 9

8 . 9 0 3

3 1 1 . 4 9 1

24 1 . 3 8 0

7 . 8 4 5

0 0 .000

436 2 . 6 3 9

0 0 . 0 0 0

5 6 7 2 .754

4TH 5TH

3 1 0 . 4 7 7 1 . 0 0 0

3 20 . 4 7 7 1 . 3 0 1

472 3 2 5 2 . 6 7 4 2 . 5 1 2

3 0 . 4 7 7 0 . 0 0 0

5 8 0 1 . 7 6 3 0 . 0 0 0

8 0 . 9 0 3 0 . 0 0 0 7 5 5 3

2.884 . 4 7 7 2 1 0

1 . 3 2 2 0 . 0 0 0 0 0

0 .000 0 . 0 0 0 266 0

2 . 4 2 5 0 . 0 0 0 0 0

0 . 0 0 0 0 .000 1 5 2 0

2 . 1 8 2 0 . 0 0 0 0 0

0 . 0 0 0 0 . 0 0 0 0 1 6

0 .000 1 . 2 0 4 1 6 0

1 . 2 0 4 0 . 0 0 0 0 0

0 .000 0 . 0 0 0 0 0

0 . 0 0 0 0 . 0 0 0 0 6 0

0 . 0 0 0 1 . 7 7 8 1 1 5 4 5

2 .064 1 . 6 5 3 4 0

. 6 0 2 0 . 0 0 0 9 2 9 1 2 6 7

2 . 9 6 8 3 . 1 0 3

SUM

1 1 7 2 .068

3 5 1 . 5 4 4

1 2 7 9 3 . 1 0 7

7 1 1 . 8 5 1

4 87 2 . 6 8 8

9 3 1 . 9 6 8

3 9 5 2 3 . 5 9 7

2 4 8 2 .394

6 8 1 . 8 3 3

8 6 0 2 . 9 3 4

1 8 1 . 2 5 5

8 0 4 2 . 9 0 5

6 3 5 2 . 8 0 3

8 2 1 . 9 1 4

8 9 1 . 9 4 9

4 6 1 2 . 6 6 4

7 . 8 4 5

5 3 1 . 7 9 9

2 1 0 1 3 . 3 2 2

1 7 1 2 . 2 3 3

3 1 2 7 3 . 4 9 5

APPENDIX 5.2


BIGRAM POSITION 1ST

CH 1371 3.137

CI 177 2.248

CK 0 0.000

CL 438 2.641

CN 0 0.000

CO 2059 3.314

CR 311 2.493

cs 0 0.000

CT 0 0.000

cu 83 1.919

CY 10 1.000

DA 329 2.517

DD 0 0.000

DE 1235 3.092

DF 0 0.000

DG 0 0.000

DH 0 0.000

DI 392 2.593

DJ 0 0.000

DL 0 0.000

DM 0 0.000

2N D

546 2.737

0 0.000

0 0.000

0 0.000

0 0.000

35 1.544

370 2.568

0 0.000

555 2.144

0 0.000

0 0.000

0 0.000

22 1.342

16 1.204

0 0.000

5 .699

4 .602

87 1.940

16 1.204

0 0.000

10 1.000

3RD

174 2.241

538 2.731

468 2.670

23 1.362

15 1.176

998 2.999 119

2.076

0 0.000

297 2.473

130 2.114

0 0.000

19 1.279

310 2.491

604 2.781

3 .477

123 2.090

0 0.000

379 2.579

0 0.000

0 0.000

3 .477

4TH

13 1.114

46 1.663

186 2.270

102 2.009

0 0.000

60 1.778

0 0.000

0 0.000

5 .699

33 1.519

0 0.000

2 54 2.405

0 0.000

1285 3.109

0 0.000

105 2.021

8 .903

101 2.004

0 0.000 469

2.671

0 0.000

5TH

779 2.892

0 0.000

167 2.223

0 0.000

0 0.000

27 1.431

0 0.000

51 1.708

761 2.881

0 0.000

287 2.458

45 1.653

0 0.000

460 2.663

0 0.000

0 0.000

0 0.000

0 0.000

0 0.000

0 0.000

0 0.000

SUM

2883 3.460 761

2.881

821 2.914

563 2.751

15 1.176 3179 3.502

800 2.903

51 1.708

1618 3.209

246 2.391

297 2.473

647 2.811

332 2.521

3600 3.556

3 .477

233 2.367

12 1.079

959 2.982

16 1.204 469

2.671

13 1.114

207

208 CHAPTER 5



DN 0 0 .000

DO 2 9 3 2 .467

DR 236 2 . 3 7 3

D S 0 0 . 0 0 0

DT 0 0 .000

DU 6 4 9 2 .812

DV 0 0 . 0 0 0

DW 1 2 1 . 0 7 9

DY 0 0 .000

E A 2 3 1 2 . 3 6 4

E B 0 0 . 0 0 0

EC 1 5 1 . 1 7 6

E D 1 3 4 2 . 1 2 7

E E 0 0 . 0 0 0

EF 3 5 8 2 . 5 5 4

EG 0 0 .000

E H 0 0 . 0 0 0

E I 3 4 4 2 .537

E J 0 0 . 0 0 0

E K 0 0 . 0 0 0

E L 8 9 1 . 9 4 9

2N D

0 0 . 0 0 0

0 0 . 0 0 0

0 0 .000

0 0 . 0 0 0

0 0 . 0 0 0

2 3 1 . 3 6 2

6 6 1 . 8 2 0

4 5 1 . 6 5 3

0 0 . 0 0 0

1 8 7 5 3 . 2 7 3

7 4 1 . 8 6 9

1 6 3 8 3 . 2 1 4

1 3 1 2 . 1 1 7

7 7 7 2 . 8 9 0

1 1 8 0 3 .072

4 28 2 . 6 3 1

304 2 . 4 8 3

1 9 6 2 .292

1 0 1 . 0 0 0

0 0 . 0 0 0

586 2 .768

3RD

20 1 . 3 0 1

8 . 9 0 3

1 5 1 . 1 7 6

5 6 1 . 7 4 8

5 . 6 9 9

a 8 1 . 9 4 4

0 0 . 0 0 0

1 5 1 . 1 7 6

0 0 .000

410 2 . 6 1 3

11 1 . 0 4 1

1 0 9 2 . 0 3 7

282 2 . 4 5 0

274 2 . 4 3 8

8 5 1 . 9 2 9

11 1 . 0 4 1

0 0 . 0 0 0

111 2 . 0 4 5

0 0 . 0 0 0

24 1 . 3 8 0

1 6 3 2 . 2 1 2

4TH 5TH

0 0 0 . 0 0 0 0 . 0 0 0

3 9 8 0 2 . 6 0 0 0 . 0 0 0

11 0 1 . 0 4 1 0 . 0 0 0

3 5 3 5 . 4 7 7 2 . 7 2 8

0 1 0 0 . 0 0 0 1 . 0 0 0

4 0 . 6 0 2 0 . 0 0 0

0 0 0 .000 0 . 0 0 0

0 0 0 . 0 0 0 0 . 0 0 0

0 234 0 . 0 0 0 2 . 3 6 9

5 9 3 6 2 . 7 7 3 . 7 7 8

8 0 . 9 0 3 0 . 0 0 0 7 4 3 0

2 . 8 7 1 0 .000 3 5 8 5 8 5

1 . 9 2 9 3 . 9 3 4 7 0 3 224

2 . 8 4 7 2 . 3 5 0 6 1 3 0

. 7 7 8 2 . 1 1 4 3 0

. 4 7 7 0 . 0 0 0 0 0

0 . 0 0 0 0 . 0 0 0 3 1 3

. 4 7 7 1 . 1 1 4 0 0

0 . 0 0 0 0 . 0 0 0 1 8 5

1 . 2 5 5 . 6 9 9 1 5 0 9 3 2 5

3 .179 2 . 5 1 2

SUM

20 1 . 3 0 1

6 9 9 2 . 8 4 4

262 2 . 4 1 8

594 2 . 7 7 4

1 5 1 . 1 7 6

7 6 4 2 .883

66 1 . 8 2 0

7 2 1 . 8 5 7

234 2 . 3 6 9

3 1 1 5 3 . 4 9 3

9 3 1 . 9 6 8

2505 3 .399

9 2 1 7 3 . 9 6 5

1 9 7 8 3 .296

1 7 5 9 3 . 2 4 5

442 2 . 6 4 5

304 2 . 4 8 3

6 5 7 2 .824

1 0 1 . 0 0 0

47 1 . 6 7 2

2 6 7 2 3 .427

APPENDIX 5 .2


BIGRAM POSITION 1ST

EM 62 1 . 7 9 2

E N 886 2 .947

E O 0 0 .000

EP 0 0 .000

E Q 2 3 1 . 3 6 2

E R 7 3 1 . 8 6 3

ES 1 4 4 2 .158

ET 32 1 . 5 0 5

E U 1 4 3 2 .155

EV 1 2 6 2 .100

EW 0 0 .000

E X 649 2 .812

E Y 4 . 602

E Z 0 0 .000

FA 997 2 .999

FE 1 6 5 2 .217

FF 0 0 .000

F I 8 0 3 2 .905

FL 218 2 .338

FO 926 2 .967

FR 573 2 .758

2ND

685 2 .836

936 2 . 9 7 1

976 2 .989

3 4 3 2 .535

0 0 .000

1 5 5 1 3 .191

769

1 0 7 1 3.030

9 .954

312 2 .494

1 7 7 2 .248

97 1 . 9 8 7

1 8 3 2 .262

0 0 .000

0 0 .000

0 0 .000

7 9 1 2.898

0 0 .000

1 0 1 .000

0 0 .000

1 0 2 2 .009

2 .886

3RD

360 2 .556

8 0 3 2 .905

1 2 9 2 .111

7 6 1 . 8 8 1

0 0 .000

2 52 2 .401

8 2 1 . 9 1 4

2 53 2 .403

0 0 .000

6 3 1 . 7 9 9

3 3 1 . 5 1 9

1 0 1 . 0 0 0

7 . 845

0 0 .000

57 1 .756

434 2 .637

1 6 2 2 .210

301 2 .479

3 1 1 . 4 9 1

1 2 5 6 3 .099

52 1 . 7 1 6

4TH

4 8 1 . 6 8 1

1 2 7 4 3 .105

3 .477

314 2 .497

0 0 .000

1 4 6 1 3 .165

6 0 1 2 .779

1 3 0 2 .114

3 2 1 . 5 0 5

28 1 . 4 4 7

24 1 . 3 8 0

0 0 . 0 0 0

0 0 .000

3 3 1 . 5 1 9

0 0 .000

1 8 5 2 .267

1 2 1 . 0 7 9

5 1 1 . 7 0 8

1 2 1 . 0 7 9

0 0 .000

0 0 .000

5TH

4 3 5 2 .638

1 0 9 9 3 . 0 4 1

1 2 1 . 0 7 9

3 5 1 . 5 4 4

0 0 .000

6964 3 .843

3 7 3 5 3 .572

1164 3 .066

4 . 6 0 2

0 0 .000

8 7 1 . 9 4 0

4 . 602

284 2 . 4 5 3

0 0 .000

0 0 .000

6 . 778

9 .9 54

0 0 .000

0 0 .000

0 0 .000

0 0 .000

S U M

1590 3 . 2 0 1

4998 3 . 6 9 9

1 1 2 0 3 .049

7 6 8 2 .885

2 3 1 . 3 6 2 1 0 3 0 1 4 .013

5 3 3 1 3 .727

2650 3 . 4 2 3

1 8 8 2 .274

529 2 . 7 2 3

3 2 1 2 .507

760 2 .881

478 2 .679

3 3 1 . 5 1 9

1054 3 . 0 2 3

790 2 .898

974 2 .989

1 1 5 5 3 . 0 6 3

271 2 .433

2182 3 . 3 3 9

727 2 .862

209

210 CHAPTER 5



FS 0 0 .000

FT 0 0 .000

FU 271 2 .433

FY 0 0 .000

G A 1 9 6 2 .292

G E 322 2 .508

G G 0 0 .000

G H 1 6 1 . 2 0 4

G I 1 3 8 2 .140

G L 8 8 1 . 9 4 4

GM 0 0 .000

G N 0 0 .000

G O 1 1 9 2 .076

G R 6 6 1 2 .820

GS 0 0 .000

GT 0 0 .000

G U 1 7 2 2 .236

GY 0 0 .000

H A 834 2 .921

H E 493 2 .693

H I 316

2ND 3RD 4TH

0 9 0 0 .000 .954 0 .000

0 9 9 26 0 .000 1 . 9 9 6 1 . 4 1 5

0 2 3 6 1 0 .000 1 . 3 6 2 1 . 7 8 5

0 0 0 0 .000 0 .000 0 .000

0 1 2 9 8 6 0 .000 2 .111 1 . 9 3 4

1 0 0 1 2 4 1 8 5 1 2 .000 2 .093 3 .022

0 1 1 7 0 0 .000 2 .068 0 .000

0 544 722 0 .000 2 .736 2 .859

0 226 1 5 0 0 .000 2 .354 2 .176

0 11 205 0 .000 1 . 0 4 1 2 .312

0 0 4 0 .000 0 .000 .602

1 9 1 2 4 0 1 . 2 7 9 2 .093 0 .000

0 36 3 3 0 .000 1 . 5 5 6 1 .519

9 2 1 3 4 2 3 1 . 9 6 4 2 . 1 2 7 1 . 3 6 2

0 0 0 0 .000 0 .000 0 .000

0 0 1 1 6 0 .000 0 .000 2 .064

0 3 0 1 1 1 0 0 .000 2 .479 2 . 0 4 1

0 0 0 0 .000 0 .000 0 .000

8 4 8 3 4 29 2 .928 1 . 5 3 1 1 .462

328 399 1 7 3 9 2 .516 2 . 6 0 1 3 .240

586 287 370

5TH

2 3 1 . 3 6 2

0 0 .000

0 0 .000

1 9 1 . 2 7 9

0 0 .000

844 2 .926

0 0 .000

872 2 .941

0 0 .000

0 0 .000

0 0 .000

1 3 2 2 .121

3 .477

0 0 .000

462 2 . 6 6 5

0 0 .000

0 0 .000

1 1 2 2 .049

18 1 . 2 5 5

1 7 1 . 2 3 0

0

SUM

32 1 . 5 0 5

1 2 5 2 .097

355 2 . 5 5 0

1 9 1 . 2 7 9

4 1 1 2 .614

2441 3 .388

1 1 7 2 .068

2154 3 .333

514 2 .711

304 2 .483

4 . 6 0 2

2 7 5 2 .439

1 9 1 2 .281

9 1 0 2 .959

462 2 . 6 6 5

1 1 6 2 .064

583 2 .766

1 1 2 2 .049

1 7 6 3 3 .246

2976 3.474

1 5 5 9 2 .500 2 .768 2 .458 2 .568 0 . 0 0 0 3 .193

APPENDIX 5 . 2



HL 0 0 . 0 0 0

HM 0 0 . 0 0 0

HN 0 0 . 0 0 0

HO 4 6 3 2 . 6 6 6

HR 0 0 . 0 0 0

HS 0 0 . 0 0 0

HT 0 0 . 0 0 0

HU 204 2 . 3 1 0

HW 0 0 . 0 0 0

HY 0 0 .000

IA 0 0 . 0 0 0

IB 0 0 . 0 0 0

IC 3 . 4 7 7

I D 1 6 1 . 2 0 4

IE 0 0 . 0 0 0

IF 0 0 . 0 0 0

IG 1 9 1 . 2 7 9

I1 0 0 .000

IK 0 0 . 0 0 0

IL 0 0 . 0 0 0

IM 1 3 8 2 . 1 4 0

2 N D

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

1 9 9 1 3 .299

3 6 1 2 .558

0 0 . 0 0 0

0 0 . 0 0 0

3 5 9 2.555

3 . 4 7 7

22 1 . 3 4 2

5 6 1 . 7 4 8

4 3 1 . 6 3 3

284 2 . 4 5 3

322 2 . 5 0 8

2 5 3 2 . 4 0 3

1 0 0 2 . 0 0 0

8 7 0 2 . 9 4 0

0 0 . 0 0 0

1 6 9 2 . 2 2 8

5 4 8 2 . 7 3 9

4 2 1 2 . 6 2 4

3RD

0 0 .000

0 0 .000

4 3 1 . 6 3 3

524 2 . 7 1 9

5 . 6 9 9

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

0 0 .000

0 0 .000

4 3 1 . 6 3 3

2 5 1 . 3 9 8

1 6 9 2 . 2 2 8

1 9 5 2 .290

2 0 3 2 . 3 0 7

3 2 1 . 5 0 5

452 2 . 6 6 5

7 . 8 4 5

0 0 .000

346 2 . 5 3 9

1 0 7 2 . 0 2 9

4TH

9 9 1 . 9 9 6

7 . 8 4 5

0 0 . 0 0 0

2 4 1 2 . 3 8 2

0 0 . 0 0 0

0 0 .000

244

5 5 1 . 7 4 0

0 0 . 0 0 0

0 0 . 0 0 0

5 3 5 2 . 7 2 8

0 0 .000

1 0 6 0 3 . 0 2 5

3 4 8 2 . 5 4 2

1 0 4 7 3 .020

3 5 1 . 5 4 4

1 3 2 2 . 1 2 1

0 0 . 0 0 0

92 1 . 9 6 4

570 2 . 7 5 6

9 7 1 . 9 8 7

2 . 3 8 7

5TH SUM

0 9 9 0 . 0 0 0 1 . 9 9 6

2 2 29 1 . 3 4 2 1 . 4 6 2

0 4 3 0 . 0 0 0 1 . 6 3 3

0 3 2 1 9 0 . 0 0 0 3 . 5 0 8

0 3 6 6 0 . 0 0 0 2 . 5 6 3

2 7 3 2 7 3 2 . 4 3 6 2 . 4 3 6

7 0 3 9 4 7 2 . 8 4 7 2 . 9 7 6

0 6 1 8 0 . 0 0 0 2 . 7 9 1

0 3 0 . 0 0 0 . 4 7 7

6 3 8 5 1 . 7 9 9 1 . 9 2 9

9 9 7 3 3 1 . 9 9 6 2 . 8 6 5

0 6 8 0 . 0 0 0 1 . 8 3 3

7 3 9 2 2 5 5 2 . 8 6 9 3 . 3 5 3

1 6 8 1 0 4 9 2 . 2 2 5 3 . 0 2 1

4 6 1 5 4 9 1 . 6 6 3 3 .190

0 1 6 7 0 . 0 0 0 2 . 2 2 3

8 1 4 9 1 . 9 0 3 3 . 1 7 3

1 6 2 3 1 . 2 0 4 1 . 3 6 2

0 2 6 1 0 . 0 0 0 2 .417

1 4 2 1 6 0 6 2 . 1 5 2 3 .206

2 7 7 9 0 1 . 4 3 1 2 . 8 9 8

2 1 1

212 C H A P T E R 5

BIGRAM F R E Q U E N C I E S F O R WORDS O F L E T T E R LENGTH 6


I N 8 7 3 2 . 9 4 1

I0 0 0.000

I P 0 0.000

IQ 0 0.000

I R 1 7 1 . 2 3 0

I S 298 2 .474

I T 3 0 4 2.483

I U 0 0.000

I V 0 0.000

I X 0 0.000

I 2 0 0.00Q

J A 5 0 1.699

J E 1 1 9 2.076

J O 1 7 6 2.246

J U 1 9 6 2.292

KA 3 1 1 . 4 9 1

KE 6 .778

K I 1 5 2 2.182

KL 0 0 .000

KN 25 1.398

KO 11 1 . 0 4 1

2 N D

8 2 8 2.918

1 8 1.255

29 1.462

9 1 1.959

389 2.590

8 0 0 2.903

1 7 5 7 3.245

0 0 .000

394 2.595

2 1 1.322

3 .477

0 0.000

0 0 .000

0 0.000

0 0.000

0 0.000

1 6 1 .204

57 1 .756

0 0.000

0 0 .000

0 0.000

3 RD

9 1 6 2 .962

3 6 1 .556

5 .699

58 1 .763

3 2 5 2.512

3 9 2 2.593

9 0 1 2 .955

0 0 .000

1 2 2 2 .086

0 0 .000

3 0 1 .477

0 0.000

8 4 1 . 9 2 4

1 3 1 . 1 1 4

43 1 . 6 3 3

0 0.000

1 7 6 2.246

543 2 .735

7 .845

0 0 .000

6 .778

4 T H

4190 3.622

1 1 0 0 3 .041

33 1 .519

0 0.000

406 2.609

480 2.681

235 2 .371

1 0 8 2.033

208 2.318

0 0.000

0 0.000

0 0.000

0 0.000

0 0.000

0 0.000

0 0 .000

1 9 2 7 3.285

1 2 1 .079

42 1.623

0 0.000

7 .845

5 T H

9 1 5 2 .961

3 1 1 .491

3 4 1 . 5 3 1

0 0.000

7 3 1 .863

1 6 7 2.223

444 2.647

0 0.000

0 0.000

0 0.000

0 0.000

0 0.000

0 0 .000

0 0.000

0 0 .000

2 2 1 .342

1 2 7 2.104

0 0.000

Q 0.000

0 0 .000

0 0.000

SUM.

7 7 2 2 3.888

1 1 8 5 3.074

1 0 1 2.004

1 4 9 2.173

1 2 1 0 3.083

2137 3.330

3 6 4 1 3.561

1 0 8 2.033

7 2 4 2.860

2 1 1 . 3 2 2

33 1 .519

50 1 .699

203 2.307

1 8 9 2.276

239 2.378

53 1.724

2252 3 .353

7 6 4 2.883

49 1.690

25 1.398

24 1.380

APPENDIX 5.2



KS 0 0 .000

K U 0 0 .000

K Y 0 0 . 0 0 0

LA 5 1 8 2.714

L B 0 0 .000

L D 0 0 .000

L E 7 1 8 2.856

LF 0 0 * 0 0 0

LG 0 0 .000

L I 1 6 0 5 3 . 2 0 5

LK 0 0 .000

L L 0 0 .000

LM 0 0 . 0 0 0

L N 0 0 .000

L O 9 7 8 2 . 9 9 0

LP 0 0 . 0 0 0

LS 0 0 . 0 0 0

LT 0 0 . 0 0 0

L U 8 1 1 . 9 0 8

LV 0 0 . 0 0 0

LW 0 0 . 0 0 0

2ND

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

9 1 4 2 . 9 6 1

47 1 . 6 7 2

28 1 . 4 4 7

210 2 . 3 2 2

52 1 . 7 1 6

0 0 . 0 0 0

1 7 3 2 . 2 3 8

0 0 . 0 0 0

7 8 1 . 8 9 2

432 2 . 6 3 5

0 0 .000

536 2 . 7 2 9

0 0 .000

0 0 .000

0 0 .000

57 1 . 7 5 6

0 0 . 0 0 0

4 58 2 . 6 6 1

3RD

0 0 .000

0 0 . 0 0 0

0 0 . 0 0 0

3 2 1 2 . 5 0 7

0 0 . 0 0 0

1 8 9 2 . 2 7 6

316 2 .500

0 0 .000

1 0 1 . 0 0 0

7 7 3 2 . 8 8 8

234 2 . 3 6 9

1 4 7 1 3 .168

1 1 7 2 . 0 6 8

11 1 . 0 4 1

1 9 3 2 .286

7 9 1 . 8 9 8

7 8 1 . 8 9 2

1 4 4 2 . 1 5 8

4 1 3 2 . 6 1 6

6 8 1 . 8 3 3

0 0 . 0 0 0

4TH

0 0 . 0 0 0

1 4 1 . 1 4 6

0 0 .000

1 5 5 2 . 1 9 0

0 0 . 0 0 0

9 3 1 . 9 6 8

1 6 3 5 3 . 2 1 4

0 0 . 0 0 0

0 0 .000

5 7 7 2 . 7 6 1

0 0 . 0 0 0

3 9 1 2 . 5 9 2

0 0 . 0 0 0

0 0 . 0 0 0

3 4 2 2 . 5 3 4

0 0 . 0 0 0

0 0 . 0 0 0

1 9 4 2 . 2 8 8

4 . 6 0 2

5 3 1 . 7 2 4

0 0 . 0 0 0

5TH

3 6 0 2 . 5 5 6

0 0 . 0 0 0

3 2 1 . 5 0 5

1 9 1 . 2 7 9

0 0 . 0 0 0

1 0 0 4 3 . 0 0 2

3 4 9 9 3 . 5 4 4

4 5 4 2 . 6 5 7

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

81 1 . 9 0 8

0 0 . 0 0 0

0 0 . 0 0 0

1 3 1 . 1 1 4

0 0 . 0 0 0

500 2 . 6 9 9

2 59 2 . 4 1 3

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

S U M

3 6 0 2 . 5 5 6

1 4 1 . 1 4 6

3 2 1 . 5 0 5

1 9 2 7 3 . 2 8 5

47 1 . 6 7 2

1 3 1 4 3 . 1 1 9

6 3 7 8 3 . 8 0 5

5 0 6 2 . 7 0 4

1 0 1 . 0 0 0

3 1 2 8 3 . 4 9 5

234 2 . 3 6 9

2 0 2 1 3 . 3 0 6

5 4 9 2 . 7 4 0

11 1 . 0 4 1

2062 3 .314

7 9 1 . 8 9 8

5 7 8 2 . 7 6 2

597 2 . 1 7 6

5 5 5 2 . 7 4 4

1 2 1 2 . 0 8 3

458 2 . 6 6 1

2 1 3

214 CHAPTER 5


BIGRAM POSITION ~~~

1ST

LY 1 8 1 . 2 5 5

MA 1 4 9 3 3 .174

MB 0 0 .000

ME 8 0 1 2 .904

MI 436 2 .639

ML 0 0 .000

M M 0 0 .000

MN 0 0 .000

MO 1637 3 .214

MP 0 0 .000

MS 0 0 .000

MT 0 0 .000

M U 215 2 .332

MY 1 3 6 2.134

NA 512 2 .709

N B 0 0 .000

NC 0 0 .000

N D 0 0 .000

N E 519 2 .715

NF 0 0 .000

N G 0 0 .000

2ND

4 3 1 .633

48 1 . 6 8 1

1 2 1 . 0 7 9

27 1 . 4 3 1

8 5 1 . 9 2 9

0 0 .000

5 .699

0 0 .000

223 2 .348

1 3 5 2 .130

0 0 .000

0 0 .000

9 . 954

4 . 6 0 2

1 1 3 2 .053

4 . 602

216 2 .334

297 2 .473

1 2 8 2 .107

3 5 1.544

1 0 7 2 .029

3RD

0 0 .000

346 2 .539

788 2 .897

420 2 .623

6 1 3 2 .787

7 . 8 4 5

433 2 .636

1 9 1 .279

7 07 2 .849

532 2 .726

1 0 1 . 0 0 0

0 0 .000

3 7 1 . 5 6 8

0 0 .000

1 9 3 2 .286

0 0 .000

1 5 7 2 .196

717 2 .856

236 2 .373

6 . 778 7 7 3

2 .888

4TH

4 . 602

540 2.732

1 2 1 .079

988 2 .995

1 9 4 2.288

7 9 1 . 8 9 8

0 0 .000

9 .954

248 2 .394

3 2 1 . 5 0 5

6 . 778

28 1 .447

7 . 845

0 0 .000

6 6 1 . 8 2 0

0 0 .000

544 2 .736

284 2 .453

1 3 6 2 3 .134

0 0 .000

765 2 .884

5TH

2892 3 .461

28 1 .447

0 0 .000

1 0 2 2 3 .009

7 . 845

0 0 .000

0 0 .000

1 0 5 2 .021

0 0 .000

0 0 .000

1 2 0 2 .079

0 0 .000

0 0 .000

1 5 1 . 1 7 6

5 1 1 .708

0 0 .000

0 0 .000

2237 3 .350

447 2.650

0 0 .000

3776 3 .577

SUM

2957 3 .471

2455 3 .390

812 2 .910

3258 3 .513

1 3 3 5 3 .125

8 6 1 . 9 3 4

4 38 2 .641

1 3 3 2 .124

281 5 3 .449

699 2 .844

1 3 6 2 .134

28 1 . 4 4 7

268 2 .428

1 5 5 2 .190

9 3 5 2 . 9 7 1

4 . 602

917 2 .962

3535 3 .548

2692 3 .430

4 1 1 . 6 1 3

5 4 2 1 3 .734

APPENDIX 5.2


BIGRAM POSITION 1ST

NI 68 1.833

NJ 0 0.000

NK 0 0.000

NL 0 0.000

NM 0 0.000

NN 0 0.000

NO 450 2.653

NP 0 0.000

NR 0 0.000

NS 0 0.000

NT 0 0.000

NU 494 2.694

NV 0 0.000

NW 0 0.000

NY 0 0.000

NZ 0 0.000

OA 0 0.000

OB 114 2.057

oc 46 1.663

OD 3 .477

OE 0 0.000

2N D

673 2.828

43 1.633

10 1.000

165 2.217

0 0.000

113 2.053

430 2.633

9 .954

25 1.398

445 2.648

231 2.364

3 .477

35 1.544

12 1.079

206 2.314

6 .778

131 2.117

214 2.330

624 2.795 4 36

2.639 119

2.076

3RD

380 2.580

0 0.000

72 1.857

6 .778

3 .477

582 2.765

72 1.857

0 0.000

22 1.342

118 2.072

955 2.980

176 2.246

51 1.708

4 .602

12 1.079

0 0.000

28 1.447

7 .845

67 1.826

71 1.851

0 0.000

4TH

71 1.851

0 0.000

100 2.000

75 1.875

0 0.000

67 1.826

286 2.456

0 0.000

0 0.000

0 0.000

7 51 2.876

63 1.799

0 0.000

0 0.000

0 0.000

17 1.230

116 2.064

0 0.000

3 .477 123

2.090 32

1.505

5TH

9 .954

0 0.000

5 .699

0 0.000

0 Q.OOO

0 0.000

0 0.000

0 0.000

0 0.000

3 07 2.487

1086 3.036

0 0.000

0 0.000

0 0.000

87 1.940

0 0.000

0 0.000

0 0.000

0 0.000 4 07

2.610 12

1.079

SUM

1201 3.080

43 1.633

187 2.272

246 2.391

3 .477

762 2.882

1238 3.093

9 .954

47 1.672

870 2.940

3023 3.480

736 2.867

86 1.934

16 1.204

305 2.484

23 1.362

275 2.439

335 2.525 740

2.869 1040

3.017 163

2.212

215

216 CHAPTER 5


BIGRAM POSITION 1ST

OF 313 2 .496

OG 0 0 .000

OH 0 0 .000

01 0 0 .000

OK 0 0 .000

OL 2 1 1 . 3 2 2

OM 0 0 .000

ON 8 . 9 0 3

00 0 0 .000

OP 1 9 7 2.294

OR 1 7 8 2 .250

0s 0 0 .000

OT 323 2 .509

ou 8 2 1 . 9 1 4

ov 8 . 9 0 3

OW 38 1 .580

ox 6 1 1 . 7 8 5

OY 6 . 778

0 2 0 0 .000

PA 8 4 9 2 .929

PE 1450 3 .161

2ND

1 2 5 2 .097

9 . 954

30 1 .477

314 2 .497

1 0 1 . 0 0 0

1 1 8 9 3 .075

7 8 1 2 .893

8 4 9 2 .929

592 2 .772

1 0 4 2 .017

1 5 2 3 3 . 1 8 3

428 2 . 6 3 1

8 5 3 2 . 9 3 1

1 6 0 6 3 .206

407 2 .610

598 2 .777

0 0 .000

26 1 . 4 1 5

1 8 1 . 2 5 5

44 1 . 6 4 3

278 2 .444

3 RD

28 1 .447

7 . 845

0 0 .000

1 1 6 2 .064

5 3 1 2 .725

1 1 4 2 .057

1 7 9 2 . 2 5 3

1 0 5 2 . 0 2 1

1 9 3 2 .286

1 0 0 7 3 .003

392 2 .593

2 68 2 .428

72 1 . 8 5 7

2869 3 .458

1 3 0 2 .114

504 2 .702

0 0 .000

0 0 .000

27 1 . 4 3 1

1 2 7 2 .104

5 1 1 2 .708

4TH

0 0 .000

0 0 .000

0 0 .000

30 1 . 4 7 7

39 1 . 5 9 1

8 5 1 . 9 2 9

4 8 1 2 .682

1 0 3 0 3 . 0 1 3

526 2 .721

1 7 1 2 .233

2101 3 .322

8 0 3 2 . 9 0 5

1 0 7 2 .029

1 2 3 2 .090

62 1 . 7 9 2

8 3 1 .919

0 0 .000

1 0 1 . 0 0 0

0 0 .000

0 0 .000

639 2 .806

STH

0 0 .000

0 0 .000

0 0 .000

0 0 .000

0 0 .000

598 2 .777

223 2 .348

2267 3 . 3 5 5

0 0 .000

22 1 . 3 4 2

762 2 .882

3 5 1 . 5 4 4

288 2 .459

0 0 .000

0 0.000

5 7 3 2 .758

3 . 477

3 1 1 . 4 9 1

0 0 .000

0 0 .000

1 9 7 2 .294

SUM

466 2 .668

1 6 1 . 2 0 4

3 0 1 .477

460 2 .663

580 2 . 7 6 3

2007 3 .303

1 6 6 4 3 . 2 2 1

4259 3 .629

1 3 1 1 3 .118

1 5 0 1 3 .176

4956 3 .695

1 5 3 4 3 .186

1 6 4 3 3 .216

4680 3 .670

607 2 .783

1 7 9 6 3 .254

6 4 1 . 8 0 6

7 3 1 . 8 6 3

4 5 1 . 6 5 3

1 0 2 0 3 .009

3075 3 .488

APPENDIX 5 . 2



PH 1 0 8 2 . 0 3 3

P I 3 1 3 2 . 4 9 6

PK 0 0 . 0 0 0

PL 6 8 8 2 . 8 3 8

PO 1 0 7 5 3 . 0 3 1

PP 0 0 .000

PR 6 1 0 2 . 7 8 5

PS 7 . 8 4 5

PT 0 0 . 0 0 0

PU 7 2 7 2 . 8 6 2

PW 0 0 .000

PY 0 0 . 0 0 0

Qu 7 0 1 . 8 4 5

RA 8 1 7 2 . 9 1 2

RB 0 0 . 0 0 0

RC 0 0 . 0 0 0

RD 0 0 . 0 0 0

R E 2 6 4 3 3 .422

RG 47 0 . 0 0 0

RH 30 1 . 4 7 7

R I 312 2 .494

2ND

3 5 1 . 5 4 4

1 9 3 2 . 2 8 6

6 . 7 7 8

3 . 4 7 7

1 0 1 2 . 0 0 4

1 9 5 2 . 2 9 0

239 2 . 3 7 8

11 1 . 0 4 1

22 1 . 3 4 2

0 0 . 0 0 0

27 1 . 4 3 1

0 0 . 0 0 0

1 6 6 2 .220

674 2 . 8 2 9

9 . 9 5 4

2 1 1 . 3 2 2

7 3 1 . 8 6 3

7 0 9 2 . 8 5 1

9 1 1 . 9 5 9

0 0 .000

1 2 3 1 3 .090

3RD

9 . 9 5 4

1 5 6 2 . 1 9 3

3 . 4 7 7

1 2 1 . 0 7 9

2 3 3 2 . 3 6 7

2 9 8 2 . 4 7 4

6 . 7 7 8

7 . 8 4 5

1 9 1 . 2 7 9

1 7 1 . 2 3 0

0 0 . 0 0 0

0 0 . 0 0 0

9 1 1 . 9 5 9

269 2 . 4 3 0

1 3 2 2 . 1 2 1

404 2 . 6 0 6

360 2 . 5 5 6

1 4 3 6 3 . 1 5 7

417 2 .620

0 0 . 0 0 0

1 7 5 6 3 . 2 4 5

4TH

15 1 . 1 7 6

5 2 1 . 7 1 6

0 0 . 0 0 0

1 5 6 4 3 . 1 9 4

46 1 . 6 6 3

3 . 4 7 1

0 0 . 0 0 0

7 . 8 4 5

0 0 . 0 0 0

7 5 1 . 8 7 5

0 0 . 0 0 0

0 0 . 0 0 0

6 4 1 . 8 0 6

4 1 1 . 6 1 3

44 1 . 6 4 3

5 2 8 2 . 7 2 3

1 1 8 2 . 0 7 2

9 0 9 2 . 9 5 9

3 8 1 2 . 5 8 1

0 0 . 0 0 0

2 6 8 2 . 4 2 8

5TH

5 5 1 . 7 4 0

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

2 1 1 2 . 3 2 4

2 9 8 2 . 4 7 4

0 0 . 0 0 0

0 0 . 0 0 0

2 5 1 . 3 9 8

0 0 . 0 0 0

40 1 . 6 0 2

40 1 . 6 0 2

0 0 . 0 0 0

8 7 5 2 . 9 4 2

2 3 6 4 3 . 3 7 4

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

S U M

2 2 2 2 .346

7 1 4 2 .854

9 . 9 5 4 2 267

3 . 3 5 5 1 4 5 5

3 . 1 6 3 496

2 . 6 9 5 8 5 5

2 . 9 3 2 243

2 .386 3 39

2 . 5 3 0 8 1 9

2 . 9 1 3 27

1 . 4 3 1 2 5

1 . 3 9 8 3 9 1

2 .592 1 8 4 1

3 . 2 6 5 2 2 5

2 . 3 5 2 9 5 3

2 .979 1 4 2 6

3.154 8 0 6 1

3.906 8 8 9

2 . 9 4 9 3 0

1 . 4 7 7 3 5 6 7

3 . 5 5 2

2 1 7

2 1 8 CHAPTER 5



RK 0 0 .000

RL 0 0 .000

RM 0 0 . 0 0 0

RN 0 0 . 0 0 0

R O 254 2 . 4 0 5

RP 0 0 .000

R R 0 0 . 0 0 0

RS 0 0 .000

RT 0 0 .000

RU 220 2 . 3 4 2

RV 0 0 . 0 0 0

RY 0 0 .000

SA 530 2 . 7 2 4

SC 7 2 2 2 . 8 5 9

SD 0 0 .000

SE 1 8 4 6 3 .266

SH 1 4 6 4 3 . 1 6 6

S I 8 3 6 2 . 9 2 2

SK 7 3 1 . 8 6 3

SL 2 9 1 2 .464

SM 1 4 6

2ND

0 0 . 0 0 0

0 0 . 0 0 0

1 5 1 . 1 7 6

3 0 1 . 4 7 7

1 5 2 0 3 .182

0 0 . 0 0 0

1 0 0 2 .000

0 0 . 0 0 0

1 5 4 2 . 1 8 8

8 5 1 . 9 2 9

4 . 6 0 2

207 2 . 3 1 6

11 1 . 0 4 1

7 4 1 . 8 6 9

0 0 . 0 0 0

5 8 1 . 7 6 3

6 . 7 7 8

0 0 . 0 0 0

6 7 1 . 8 2 6

1 9 6 2 .292

0

3RD

5 4 2 2 . 7 3 4

1 4 0 2 . 1 4 6

7 4 5 2 .872

5 6 1 2 . 7 4 9

9 5 3 2 .979

5 0 1 . 6 9 9

3 1 1 2 . 4 9 3

340 2 . 5 3 1

2 8 6 2 . 4 5 6

1 2 4 2 . 0 9 3

2 9 3 2 . 4 6 7

0 0 . 0 0 0

3 5 1 . 5 4 4

220 2 . 3 4 2

4 4 1 . 6 4 3

6 7 7 2 . 8 3 1

2 7 6 2 . 4 4 1

8 9 7 2 . 9 5 3

2 5 1 . 3 9 8

3 . 4 7 7

3 4 2 . 1 6 4 0 .000 1 . 5 3 1

4TH

1 5 1 . 1 7 6

237 2 . 3 7 5

1 4 1 . 1 4 6

1 0 1 . 0 0 0

1 9 9 2 . 2 9 9

0 0 .000

4 2 1 . 6 2 3

489 2 . 6 8 9

3 6 3 2 .560

2 2 1 . 3 4 2

0 0 . 0 0 0

0 0 . 0 0 0

6 1 1 . 7 8 5

4 . 6 0 2

0 0 .000

1 3 8 4 3 . 1 4 1

3 . 4 7 7

2 2 8 2 . 3 5 8

4 5 1 . 6 5 3

0 0 . 0 0 0

1 3 1 . 1 1 4

5TH

44 1 . 6 4 3

0 0 .000

49 1 . 6 9 0

3 9 9 2 . 6 0 1

3 2 1 . 5 0 5

0 0 . 0 0 0

0 0 . 0 0 0

1 2 0 0 3 . 0 7 9

6 0 2 2 . 7 8 0

0 0 . 0 0 0

0 0 .000

5 4 3 2 . 7 3 5

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

8 1 9 2 . 9 1 3

1 8 8 2 . 2 7 4

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

1 3 1 . 1 1 4

SUM

6 0 1 2 . 7 7 9

377 2 . 5 7 6

8 2 3 2 . 9 1 5

1 0 0 0 3 . 0 0 0

2958 3 . 4 7 1

5 0 1 . 6 9 9

4 5 3 2 . 6 5 6

2 0 2 9 3 . 3 0 7

1 4 0 5 3 . 1 4 8

4 5 1 2 . 6 5 4

2 9 7 2 . 4 7 3

7 5 0 2 . 8 7 5

6 3 7 2 . 8 0 4

1 0 2 0 3 . 0 0 9

44 1 . 6 4 3

4784 3 . 6 8 0

1 9 3 7 3 .287

1 9 6 1 3 . 2 9 2

210 2 . 3 2 2

490 2 . 6 9 0

2 0 6 2 . 3 1 4

APPENDIX 5.2


BIGRAM POSITION 1ST

SN 36 1.556

SO 886 2.947

SP 698 2.844

SQ 143 2.155

SR 0 0.000

ss 0 0.000

ST 2484 3.395

SU 704 2.848

sw 83 1.919

SY 481 2.682

TA 519 2.715

TC 0 0.000

TE 203 2.307

TF 0 0.000

TH 1419 3.152

TI 145 2.161

TL 0 0.000

TM 0 0.000

TO 508 2.706

TP 0 0.000

TR 614 2.788

2ND

0 0.000

0 0.000

56 1.748

0 0.000

15 1.176

313 2.496

59 1.771

0 0.000

0 0.000

7 .845

1251 3.097

0 0.000

57 1.756

0 0.000

363 2.560

31 1.491

0 0.0011

7 .845

202 2.305

0 0.000

807 2.948

3RD

0 0.000

25 1.398

21 1.322

0 0.000

0 0.000

562 2.750

1132 3.054

6 07 2.783

152 2.182

0 0.000

416 2.619

0 0.000

505 2.703

16 1.204

1739 3.240

1352 3.131

50 1.699

0 0.000

74 1.869

35 1.544

63 1.799

4TH

0 0.000

817 2.912

0 0.000

0 0.000

3 .477

0 0.000

142 2.152

84 1.924

0 0.000

0 0.000

142 2.152

76 1.881

4357 3.639

0 0.000

335 2.525

197 2.294

1462 3.165

0 B.000

685 2.836

0 0.000

130 2.114

5TH

0 0.000

0 0.000

0 0.000

0 0.000

0 0.000

565 2.752

1104 3.043

0 0.000

0 0.000

28 1.447

38 1.580

0 0.000

380 2.580

0 0.000

637 2.804

0 0.000

0 0.000

0 0.000

54 1.732

0 0.000

0 0.000

SUM

36 1.556

1728 3.238

775 2.889

143 2.155

18 1.255

1440 3.158

4921 3.692

1395 3.145

235 2.371

516 2.713

2366 3.374

76 1.881

5502 3.741

16 1.204

4493 3.653

1725 3.237

1512 3.180

7 .a45

1523 3.183

35 1.544 1694 3.229

219

220 CHAPTER 5


BIGRAM POSITION 1ST

TS 0 0 .000

TT 0 0 .000

TU 370 2 .568

TW 1 4 4 2 .158

TY 7 .845

UA 0 0 .000

UB 0 0 .000

uc 0 0 .000

UD 0 0 .000

U E 0 0 .000

UF 0 0 .000

UG 0 0 .000

U I 0 0 .000

U L 0 0 .000

U M 0 0 .000

O N 874 2 .942

uo 0 0 .000

UP 74 1 . 8 6 9

UR 3 1 1 . 4 9 1

us 6 9 1 . 8 3 9

UT 3 1 1 . 4 9 1

2ND

304 2 .483

1 9 9 2 .299

1 8 3 2 .013

0 0 .000

2 3 1 . 3 6 2

44 1 . 6 4 3

577 2 .761

52 1 . 7 1 6

203 2 .307

9 6 1 .982

5 9 1 . 7 7 1

1 3 4 2 .127

1 3 3 2 .124

209 2 .320

7 59 2 .880

3 3 3 2 .522

3 1 1 . 4 9 1

1 8 8 2 .274

1544 3 .189

316 2 .500

492 2 .692

3RD

5 8 1 . 7 6 3

2414 3 . 3 8 3

809 2 .908

0 0 .000

0 0 .000

1 7 5 2 .243

8 2 1 . 9 1 4

29 1 . 4 6 2

7 3 1 . 8 6 3

5 . 699

4 . 602

316 2 .500

44 1 . 6 4 3

47 1 . 6 7 2

4 0 1 .602

352 2 .547

0 0 .000

1 5 0 2 .176

1 0 8 6 3 .036

356 2 . 5 5 1

4 1 1 . 6 1 3

4TH

0 0 .000

118 2 .072

148 2 .170

0 0 .000

8 . 903

374 2 .573

7 . 845

1 4 5 2 .161

54 1 . 7 3 2

394 2 .595

4 . 602 8 8 3

2 .946 48

1 . 6 8 1 1 1 4 5

3 .059 3 1 1

2 .493 934

2 .970 43

1 . 6 3 3 1 6 2

2 .210 1 0 7 8

3 .033 1 7 7

2 .248 1 4 9

2 .173

5TH

1 2 5 6 3 .099

5 . 699

0 0 .000

0 0 .000

779 2 .892

4 . 602

0 0 .000

0 0 .000

4 . 6 0 2

3 4 3 2 . 5 3 5

0 0 .000

0 0 .000

0 0 .000

6 4 1 . 8 0 6

1 2 8 2 .107

4 . 602

0 0 .000

1 4 1 . 1 4 6

6 2 1 . 7 9 2

338 2 .529

62 1 . 7 9 2

SUM

1 6 1 8 3 .209

2736 3 .437

1 4 3 0 3 .155

1 4 4 2 .158

817 2 . 9 1 2

597 2 .776

666 2 . 8 2 3

226 2 .354

334 2 .524

8 3 8 2 .923

67 1 . 8 2 6

1 3 3 3 3 .125

225 2 .352

1 4 6 5 3 . 1 6 6

1 2 3 8 3 .093

2497 3 .397

7 4 1 . 8 6 9

588 2 .769

3801 3 .580

1 2 5 6 3 .099

7 7 5 2 .889

APPENDIX 5 .2



u u 0 0 . 0 0 0

ux 0 0 .000

UY 0 0 . 0 0 0

uz 0 0 . 0 0 0

VA 3 8 3 2 . 5 8 3

VE 1 2 3 2 . 0 9 0

V I 3 0 9 2 . 4 9 0

VO 2 5 1 2 . 4 0 0

vu 7 . 8 4 5

WA 8 9 8 2 . 9 5 3

WB 0 0 .000

WD 0 0 . 0 0 0

WE 2 2 6 2 .354

WH 9 0 1 . 9 5 4

W I 9 1 0 2 . 9 5 9

WL 0 0 .000

WM 0 0 .000

WN 0 0 . 0 0 0

WO 3 4 1 2 .533

WR 1 8 0 2 . 2 5 5

ws 0 0 .000

2ND

0 0 .000

27 1 . 4 3 1

3 5 1 . 5 4 4

20 1 . 3 0 1

0 0 . 0 0 0

1 6 3 2 . 2 1 2

0 0 .000

20 1 . 3 0 1

0 0 .000

3 6 1 . 5 5 6

0 0 . 0 0 0

0 0 .000

1 4 7 2 . 1 6 7

4 . 6 0 2

7 9 1 . 8 9 8

0 0 . 0 0 0

0 0 .000

38 1 . 5 8 0

4 . 6 0 2

0 0 .000

0 0.000

3RD

0 0 .000

0 0 .000

0 0 .000

0 0 .000

48 1 . 6 8 1

322 2 . 5 0 8

1 1 8 5 3 . 0 7 4

5 1 1 . 7 0 8

0 0 . 0 0 0

1 0 3 9 3 . 0 1 7

16 1 . 2 0 4

2 8 1 . 4 4 7

1 4 5 2 . 1 6 1

0 0 . 0 0 0

8 7 1 . 9 4 0

0 0 . 0 0 0

1 0 1 . 0 0 0

5 . 6 9 9

0 0 . 0 0 0

0 0 . 0 0 0

3 . 4 7 7

4TH

2 0 1 . 3 0 1

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

1 9 1 . 2 7 9

9 2 9 2 . 9 6 8

1 3 1 . 1 1 4

2 3 1 . 3 6 2

0 0 . 0 0 0

6 5 1 . 8 1 3

0 0 . 0 0 0

1 2 1 . 0 7 9

4 1 8 2 . 6 2 1

0 0 . 0 0 0

7 . 8 4 5

1 1 5 2 . 0 6 1

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

5TH

0 0 . 0 0 0

4 . 6 0 2

0 0 . 0 0 0

0 0 . 0 0 0

1 7 1 . 2 3 0

3 4 7 2 . 5 4 0

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

8 . 9 0 3

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

3 . 4 7 7

0 0 . 0 0 0

51 1 . 7 0 8

0 0 . 0 0 0

0 0 . 0 0 0

4 8 1 . 6 8 1

SUM

20 1 . 3 0 1

3 1 1 . 4 9 1

3 5 544

20 3 0 1 467 6 6 9 884

3 .275 1 5 0 7

3.178 3 4 5

2 .538 7

, 8 4 5 2 0 3 8

3 . 3 0 9 1 6

1 . 2 0 4 4 8

1 . 6 8 1 9 3 6

2 . 9 7 1 94

1 . 9 7 3 1 0 8 3

3 . 0 3 5 1 1 8

2 . 0 7 2 1 0

1 . 0 0 0 9 4

1 . 9 7 3 3 4 5

2 . 5 3 8 1 8 0

2 . 2 5 5 51

1 . 7 0 8

221

2 2 2 CHAPTER 5


BIGRAM POSITION 1ST

WT 0 0 .000

WY 0 0 . 0 0 0

XA 0 0 .000

xc 0 0 . 0 0 0

X E 0 0 . 0 0 0

XF 0 0 . 0 0 0

X I 0 0 .000

XL 0 0 . 0 0 0

xo 0 0 .000

XP 0 0 . 0 0 0

XT 0 0 .000

xu 0 0 .000

X Y 0 0 .000

YA 26 1 . 4 1 5

YC 0 0 . 0 0 0

Y D 0 a . O O O

Y E 8 9 1 . 9 4 9

YG 0 0 .000

Y H 0 0 . 0 0 0

Y I 7 . 8 4 5

Y L 0 0 . 0 0 0

2ND

0 0 . 0 0 0

0 0 .000

0 0 .000

2 7 6 2 . 4 4 1

5 . 6 9 9

1 8 1 . 2 5 5

4 2 1 . 6 2 3

0 0 .000

11 1 . 0 4 1

1 6 9 2 .228

1 4 6 2 . 1 6 4

0 0 . 0 0 0

4 3 1 . 6 3 3

0 0 .000

7 . 8 4 5

5 . 6 9 9

4 . 6 0 2

0 0 .000

0 0 .000

0 0 .000

0 0 . 0 0 0

3RD

6 . 7 7 8

4 3 1 . 6 3 3

9 . 9 5 4

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

49 1 . 6 9 0

6 . 7 7 8

0 0 .000

0 0 .000

1 0 1 . 0 0 0

8 0 1 . 9 0 3

0 0 . 0 0 0

1 7 1 . 2 3 0

7 . 8 4 5

6 - 7 7 8

1 5 1 . 1 7 6

4 3 1 . 6 3 3

20 1 . 3 0 1

4 3 5 2 .638

49 1 . 6 9 0

4TH

1 5 5 2 . 1 9 0

0 0 .000

0 0 .000

0 0 . 0 0 0

1 3 1 . 1 1 4

0 0 .000

0 0 .000

0 0 .000

0 0 .000

0 0 .000

0 0 . 0 0 0

0 0 . 0 0 0

0 0 .000

0 0 . 0 0 0

0 0 .000

0 0 . 0 0 0

3 3 2 2 . 5 2 1

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

0 0 .000

5TH

0 0 . 0 0 0

0 0 . 0 0 0

0 0 .000

0 0 . 0 0 0

0 0 .000

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

0 0 .000

0 0 .000

3 . 4 7 7

0 0 . 0 0 0

0 0 .000

0 0 .000

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

SUM

1 6 1 2 .207

4 3 1 . 6 3 3

9 . 9 5 4

2 7 6 2 . 4 4 1

18 1 . 2 5 5

1 8 1 . 2 5 5

9 1 1 . 9 5 9

6 . 7 7 8

11 1 . 0 4 1

1 6 9 2 . 2 2 8

1 5 6 2 . 1 9 3

8 0 1 . 9 0 3

4 6 1 . 6 6 3

4 3 1 . 6 3 3

1 4 1 . 1 4 6

11 1 . 0 4 1

440 2 . 6 4 3

4 3 1 . 6 3 3

20 1 . 3 0 1

442 2 . 6 4 5

49 1 . 6 9 0

APPENDIX 5 .2


BIGRAM POSITION ~~

1ST

Y M 0 0 .000

Y N 0 0 . 0 0 0

Y O 18 1 . 2 5 5

YP 0 0 . 0 0 0

Y R 0 0 . 0 0 0

YS 0 0 . 0 0 0

YT 0 0 . 0 0 0

YW 0 0 . 0 0 0

Z A 0 0 . 0 0 0

Z E 0 0 . 0 0 0

Z I 0 0 . 0 0 0

Z L 0 0 . 0 0 0

20 6 . 7 7 8

Z Y 0 0 . 0 0 0

z z 0 0 . 0 0 0

2N D

54 1 . 7 3 2

1 2 1 . 0 7 9

0 0 . 0 0 0

1 0 1 . 0 0 0

22 1 . 3 4 2

5 5 1 2 . 7 4 1

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

0 0 .000

0 0 .000

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

3RD

9 .954

0 0 . 0 0 0

326 2 . 5 1 3

0 0 .000

0 0 . 0 0 0

0 0 .000

2 6 1 . 4 1 5

46 1 . 6 6 3

2 2 1 . 3 4 2

11 1 . 0 4 1

11 1 . 0 4 1

0 0 . 0 0 0

0 0 . 0 0 0

6 . 7 7 8

24 1 . 3 8 0

4TH

6 . 7 7 8

0 0 . 0 0 0

1 2 1 . 0 7 9

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

7 3 1 . 8 6 3

8 . 9 0 3

24 1 . 3 8 0

0 0 . 0 0 0

0 0 . 0 0 0

17 1 . 2 3 0

5TH

0 0 . 0 0 0

4 . 6 0 2

0 0 . 0 0 0

0 0 . 0 0 0

8 . 9 0 3

482 2 . 6 8 3

0 0 .000

0 0 . 0 0 0

1 7 1 . 2 3 0

4 7 1 . 6 7 2

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

6 . 7 7 8

0 0 . 0 0 0

S U M

6 9 1 . 8 3 9

1 6 1 . 2 0 4

3 56 2 . 5 5 1

1 0 1 . 0 0 0

3 0 1 . 4 7 7

1 0 3 3 3 .014

26 1 . 4 1 5

46 1 . 6 6 3

3 9 1 . 5 9 1

1 3 1 2 .117

1 9 1 . 2 7 9

24 1 . 3 8 0

6 . 7 7 8

1 2 1 . 0 7 9

4 1 1 . 6 1 3

2 2 3

224 CHAPTER 5


B I G R A M POSITION ~~~

1ST

AB 1 7 8 2 .250

AC 356 2 . 5 5 1

AD 285 2 .455

AE 0 0 .000

AF 1 5 0 2 .176

AG 629 2 .799

A H 0 0 .000

A 1 34 1 . 5 3 1

A J 0 0 .000

AK 0 0.000

A L 439 2 .642

AM 315 2.498

AN 1162 3 .065

A0 0 0 .800

AP 253 2 .403

AQ 1 4 1 . 1 4 6

A R 304 2 .483

AS 238 2 .377

AT 1 8 9 2 .276

AU 44 1 . 6 4 3

AV 157 2.196

2ND

1 0 1 2 .004

5 2 1 2 .717

8 7 1 . 9 4 0

4 . 602

5 .699

6 6 1 .820

0 0 .000

433 2.636

3 .477

4 . 602

574 2 .759

7 8 1 . 8 9 2

740 2 .869

4 . 6 0 2

465 2 .667

0 0 .000

1 9 3 6 3 .287

480 2 .681

972 2 .988

1 2 5 2 .097

8 0 1 . 9 0 3

3 RD

6 4 1 . 8 0 6

543 2 .735

593 2 .773

0 0 .000

81 1 .908

1 7 5 2 .243

0 0 .000

8 3 8 2 .923

0 0 .000

40 1 .602

652 2 .814

4 59 2 .662

894 2 . 9 5 1

5 . 699

232 2 . 3 6 5

4 . 602 1 1 6 0

3 .064 5 5 5

2 .744 477

2 .679 3

.477 2 58

2 .412

4TH

1 6 6 2 .220

6 5 1 . 8 1 3

1 8 0 2 .000

0 0 .000

0 0 .000

200 2 .301

6 . 778

270 2 .431

0 0 .000

67 1 . 8 2 6

650 2 .813

8 9 1 . 9 4 9

582 2 .765

0 0 .000

67 1 . 8 2 6

0 0 .000

365 2 .562

111 2 .045

8 5 3 2 . 9 3 1

9 0 8 2 .958

2 1 1 . 3 2 2

5TH

5 .699

432 2 .635

328 2 .516

11 1 . 0 4 1

0 0 .000

6 3 5 2 .803

0 0 .000

6 6 1 2 .820

0 0 .000

40 1 . 6 0 2

1 8 5 2 .267

40 1 . 6 0 2

1 0 8 6 3 . 0 3 6

0 0 .000

3 1 9 2 .504

0 0 .000

9 5 3 2 .979

1 3 8 2 .140

393 2 .594

5 .699

4 . 602

6TH

0 0 .000

5 . 699

1 8 0 2 . 2 5 5

0 0 .000

0 0 .000

3 . 477

0 0 .000

0 0 .000

0 0 .000

0 0 .000

3015 3 .479

561 2 .749

352 2 .547

0 0 .000

4 . 602

0 0 .000

547 2 .738

8 2 1 . 9 1 4

32 1 . 5 0 5

3 . 477

0 0 .000

SUM

514 2 .711

1 9 2 2 3 .284

1 5 7 3 3 .197

1 5 1 . 1 7 6

236 2 .373

1 7 0 8 3 .232

6 . 778 2236

3 .349 3

.477 151

2 .179 5515

3 . 7 4 2 1 5 4 2

3 .188 4816

3 .683 9

. 954 1 3 4 0

3 .127 18

1 . 2 5 5 5265

3 . 7 2 1 1604

3 .205 2916

3 . 4 6 5 1 0 8 8

3 .037 520

2 .716

APPENDIX 5 . 2


BIGRAM POSITION 1ST

AW 49 1 . 6 9 0

AX 0 0 . 0 0 0

AY 0 0 . 0 0 0

A2 0 0 . 0 0 0

BA 3 0 8 2 . 4 8 9

BB 0 0 . 0 0 0

BD 0 0 . 0 0 0

BE 2 4 1 3 3 . 3 8 3

BI 1 5 0 2 . 1 7 6

BJ 0 0 . 0 0 0

BL 1 8 2 2 . 2 6 0

BO 1 9 5 2 . 2 9 0

BR 7 0 2 2 .846

BS 0 0 .000

BT 0 0 . 0 0 0

BU 1 9 7 2 . 2 9 4

BV 0 0 . 0 0 0

BY 0 0 . 0 0 0

CA 8 1 3 2 . 9 1 0

cc 0 0 . 0 0 0

CE 7 8 2 2 . 8 9 3

2N D

26 1 . 4 1 5

1 0 1 2 . 0 0 4

1 5 4 2 . 1 8 8

20 1 . 3 0 1

1 7 1 . 2 3 0

0 0 .000

6 . 7 7 8

1 3 1 . 1 1 4

7 9 1 . 8 9 8

6 5 1 . 8 1 3

2 1 1 . 3 2 2

8 . 9 0 3

11 1 . 0 4 1

9 5 1 . 9 7 8

0 0 .000

0 0 . 0 0 0

9 2 1 . 9 6 4

0 0 . 0 0 0

4 5 1 . 6 5 3

1 5 7 2 . 1 9 6

26 1 . 4 1 5

3RD

8 5 1 . 9 2 9

0 0 .000

202 2 . 3 0 5

3 3 1 . 5 1 9

50 1 . 6 9 9

6 3 1 . 7 9 9

8 . 9 0 3

1 7 7 2 .248

4 3 1 . 6 3 3

1 6 1 2 . 2 0 7

8 . 9 0 3

1 4 1 . 1 4 6

1 2 7 2 . 1 0 4

8 . 9 0 3

0 0 . 0 0 0

3 1 1 . 4 9 1

0 0 . 0 0 0

0 0 * 0 0 0

1 0 5 9 3 . 0 2 5

1 0 8 2 . 0 3 3

1 5 3 2 . 1 8 5

4TH

1 0 1 . 0 0 0

17 1 . 2 3 0

3 5 1 . 5 4 4

0 0 . 0 0 0

1 7 5 2 . 2 4 3

2 3 1 . 3 6 2

0 0 . 0 0 0

5 0 2 2 . 7 0 1

7 3 1 . 8 6 3

0 0 . 0 0 0

3 9 7 2 . 5 9 9

9 8 1 . 9 9 1

4 . 6 0 2

0 0 . 0 0 0

9 . 9 5 4

7 6 1 . 8 8 1

0 0 . 0 0 0

0 0 . 0 0 0

1 1 9 2 . 0 7 6

Q 0 . 0 0 0

7 1 1 2 . 8 5 2

5TH

0 0 . 0 0 0

0 0 . 0 0 0

1 8 1 . 2 5 5

0 0 . 0 0 0

3 . 4 7 7

0 0 . 0 0 0

0 0 .000

1 8 8 2 . 2 7 4

3 3 1 . 5 1 9

0 0 . 0 0 0

3 6 4 2 . 5 6 1

1 7 1 . 2 3 0

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

Q 0 . 0 0 0

6 . 7 7 8

5 1 6 2 . 7 1 3

24 1 . 3 8 0

5 3 5 2 . 7 2 8

6TH SUM

0 1 7 0 0 . 0 0 0 2 . 2 3 0

0 1 1 8 0 . 0 0 0 2 . 0 7 2

2 5 2 6 6 1 2 . 4 0 1 2 . 8 2 0

0 5 3 0 . 0 0 0 1 . 7 2 4

0 5 5 3 0 . 0 0 0 2 . 7 4 3

0 8 6 0 . 0 0 0 1 . 9 3 4

0 1 4 0 . 0 0 0 1 . 1 4 6

7 3300 . 8 4 5 3 . 5 1 9

0 3 7 8 0 . 0 0 0 2 . 5 7 7

0 226 0 . 0 0 0 2 . 3 5 4

0 9 7 2 0 . 0 0 0 2 . 9 8 8

0 332 0 .000 2 . 5 2 1

0 8 4 4 0 . 0 0 0 2 . 9 2 6

1 8 1 2 1 1 . 2 5 5 2 . 0 8 3

0 9 0 . 0 0 0 . 9 5 4

0 304 0 . 0 0 0 2 . 4 8 3

0 9 2 0 . 0 0 0 1 . 9 6 4

6 0 6 6 1 . 7 7 8 1 . 8 2 0

1 9 4 2746 2 . 2 8 8 3 . 4 3 9

0 289 0 .000 2 . 4 6 1

1 2 9 1 3498 3 . 1 1 1 3 . 5 4 4

2 2 5

2 2 6 CHAPTER 5


BIGRAM POSITION 1ST

CH 1 0 7 5 3 . 0 3 1

C I 9 4 1 . 9 7 3

CK 0 0 . 0 0 0

C L 7 4 8 2 . 8 7 4

CN 0 0 . 0 0 0

CO 2 9 8 3 3 . 4 7 5

CQ 0 0 .000

C R 4 1 3 2 .616

CS 0 0 .000

CT 0 0 .000

cu 344 2 .537

CY 1 6 1 . 2 0 4

DA 1 4 0 2 .146

D B 0 0 .000

DC 0 0 . 0 0 0

DD 0 0 . 0 0 0

DE 1 5 4 6 3 .189

DF 0 0 . 0 0 0

DG 0 0 . 0 0 0

DH 0 0 .000

D I 517 2 . 7 1 3

2N D

267 2 .427

1 3 1 2 .117

0 0 .000

0 0 . 0 0 0

0 0 . 0 0 0

1 0 1 2 .004

27 1 . 4 3 1

56 1 . 7 4 8

6 . 7 7 8

1 2 5 2 . 0 9 7

5 . 6 9 9

0 0 .000

1 8 1 . 2 5 5

0 0 . 0 0 0

0 0 .000

8 1 1 . 9 0 8

1 0 1 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

5 . 6 9 9

6 3 1 . 7 9 9

3RD

2 0 2 2 . 3 0 5

554 2 .744

307 2 . 4 8 7

2 9 3 2 .467

3 . 4 7 7

372 2 . 5 7 1

8 . 9 0 3

4 9 1 . 6 9 0

0 0 . 0 0 0

7 1 9 2 .857

1 4 5 2 . 1 6 1

5 . 6 9 9

3 . 4 7 7

0 0 . 0 0 0

0 0 .000

9 8 1 . 9 9 1

3 8 5 2 . 5 8 5

0 0 . 0 0 0

37 1 . 5 6 8

7 . 8 4 5

2 8 5 2 . 4 5 5

4TH

7 1 8 2 . 8 5 6

5 1 3 2 .710

304 2 . 4 8 3

7 2 1 . 8 5 7

0 0 . 8 0 0

1 5 6 2 . 1 9 3

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

2 34 2 . 3 6 9

9 4 1 . 9 7 3

0 0 . 0 0 0

40 1 . 6 0 2

9 . 9 5 4

4 . 6 0 2

1 3 1 . 1 1 4

5 0 2 2 . 7 0 1

1 8 1 . 2 5 5

4 1 1 . 6 1 3

0 0 . 0 0 0

1 0 0 4 3 . 0 0 2

5TH

3 2 1 . 5 0 5

1 3 9 2 . 1 4 3

2 2 1 . 3 4 2

1 2 7 2 . 1 0 4

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

340 2 . 5 3 1

0 0 . 0 0 0

0 0 . 0 0 0

9 6 1 . 9 8 2

3 . 4 7 7

0 0 . 0 0 0

0 0 . 0 0 0

7 2 7 2 .862

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

5 . 6 9 9

6TH

7 8 1 . 8 9 2

0 0.000

3 2 1 . 5 0 5

0 0 .000

0 0 . 0 0 0

27 1 . 4 3 1

(1 0.000

0 0 .000

1 0 3 2 . 0 1 3

9 1 1 2 .960

0 0 . 0 0 0

7 1 1 . 8 5 1

46 1 . 6 6 3

0 0 . 0 0 0

0 0 .000

0 0 . 0 0 0

6 2 9 2 . 7 9 9

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

SUM

2 3 7 2 3 . 3 7 5

1 4 3 1 3 . 1 5 6

6 6 5 2 . 8 2 3

1 2 4 0 3 . 0 9 3

3 . 4 7 7 3 6 3 9

3 . 5 6 1 3 5

1 . 5 4 4 5 1 8

2 . 7 1 4 1 0 9

2 .037 2329

3 . 3 6 7 5 8 8

2 . 7 6 9 9 2

1 . 9 6 4 3 4 3

2 . 5 3 5 1 2

1 . 0 7 9 4

. 6 0 2 1 9 2

2 . 2 8 3 3 7 9 9

3 . 5 8 0 18

1 . 2 5 5 7 8

1 . 8 9 2 1 2

1 . 0 7 9 1 8 7 4

3 . 2 7 3

APPENDIX 5 . 2


B I G R A M POSITION 1 S T

D J 0 0 . 0 0 0

DL 0 0 . 0 0 0

DM 0 0 . 0 0 0

D N 0 0 . 0 0 0

DO 218 2 . 3 3 8

DR 372 2 . 5 7 1

DS 0 0 . 0 0 0

DT 0 0 . 0 0 0

DU 3 2 1 . 5 0 5

DV 0 0 . 0 0 0

DW 0 0 . 0 0 0

DY 2 1 1 . 3 2 2

E A 2 3 1 2 . 3 6 4

E B 0 0 . 0 0 0

EC 8 5 1 . 9 2 9

E D 7 0 1 . 8 4 5

E E 0 0 . 0 0 0

EF 236 2 . 3 7 3

E G 0 0 . 0 0 0

E H 0 0 . 0 0 0

E I 0 0 . 0 0 0

2ND

6 .778

0 0 . 0 0 0

20 1 . 3 0 1

0 0 .000

4 5 1 . 6 5 3

0 0 .000

0 0 . 0 0 0

0 0 . 0 0 0

7 . 8 4 5

1 1 0 2 . 0 4 1

3 . 4 7 7

4 . 6 0 2 2239

3 . 3 5 0 28

1 . 4 4 7 1 7 5 3

3 . 2 4 4 6 1 4

2 . 7 8 8 560

2 . 7 4 8 3 8 6

2 . 5 8 7 2 6 1

2 . 4 1 7 4 8

1 . 6 8 1 2 4 3

2 . 3 8 6

3 R D

0 0 .000

20 1 . 3 0 1

0 0 .000

11 1 . 0 4 1

3 5 1 . 5 4 4

1 2 9 2 . 1 1 1

5 . 6 9 9

4 . 6 0 2

1 3 8 2 . 1 4 0

0 0 . 0 0 0

11 1 . 0 4 1

0 0 . 0 0 0

9 3 4 2 . 9 7 0

4 . 6 0 2

4 54 2 . 6 5 7

6B 1 . 7 7 8

226 2 . 3 5 4

8 . 9 0 3

1 8 1 . 2 5 5

0 0 . 0 0 0

28 1 . 4 4 7

4TH

0 0 . 0 0 0

7 8 1 . 8 9 2

0 0 . 0 0 0

4 . 6 0 2

1 1 6 2 . 0 6 4

1 7 8 2 . 2 5 0

0 0 . 0 0 0

0 0 . 0 0 0

2 5 1 2 . 4 0 0

0 0 . 0 0 0

5 . 6 9 9

0 0 . 0 0 0

6 8 3 2 . 8 3 4

0 0 . 0 0 0

3 3 6 2 . 5 2 6

1 5 9 2 . 2 0 1

1 0 5 2 . 8 2 1

2 0 3 2 . 3 0 7

3 2 1 . 5 0 5

7 2 1 . 8 5 7

2 5 1 2 . 4 0 0

5TH

0 0 . 0 0 0

1 3 6 2 .134

1 3 1 . 1 1 4

0 0 . 0 0 0

1 9 9 2 . 2 9 9

5 . 6 9 9

0 (jl. 0 0 0

7 . 8 4 5

11 1 . 0 4 1

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

3 6 4 2 . 5 6 1

52 1 . 7 1 6

6 40 2 . 8 0 6

2 1 0 2 . 3 2 2

9 1 9 2 . 9 6 3

2 3 1 . 3 6 2

267 2 . 4 2 7

0 0 . 0 0 0

3 5 1 . 5 4 4

6TH

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

7 . 8 4 5

0 0 . 0 0 0

8 67 2 .938

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

510 2 .708

0 0 .000

0 0 . 0 0 0

0 0 . 0 0 0

7 7 6 0 3 .890

2 8 1 . 4 4 7

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

2 2 7

SUM

6 . 7 7 8

234 2 . 3 6 9

3 3 1 . 5 1 9

1 5 1 . 1 7 6

6 2 0 2 .792

684 2 . 8 3 5

8 7 2 2 . 9 4 1

11 1 . 0 4 1

439 2 . 6 4 2

1 1 0 2 . 0 4 1

1 9 1 . 2 7 9

5 3 5 2 . 7 2 8

4 4 5 1 3 . 6 4 8

84 1 . 9 2 4

3268 3 . 5 1 4

8 8 7 3 3 . 9 4 8

1 8 3 8 3 . 2 6 4

8 56 2 . 9 3 2

5 7 8 2 . 7 6 2

1 2 0 2 . 0 7 9

5 57 2 . 7 4 6

228 CHAPTER 5


BIGRAM POSITION 1ST

E J 0 0 .000

EK 0 0 .000

E L 1 3 9 2 .143

EM 1 6 8 2 .225

E N 747 2 .873

E O 0 0.000

EP 1 2 1 .079

E Q 7 0 1 . 8 4 5

E R 37 1 .568

ES 4 5 1 . 6 5 3

ET . 58 1 . 7 6 3

E U 0 0 .000

EV 205 2 .312

EW 0 0 .000

E X 954 2 .980

EY 11 1 . 0 4 1

E Z 0 0 .000

FA 674 2 .829

FE 554 2 .744

FF 0 0 .000

F I 707 2 .849

2N D

11 1 . 0 4 1

0 0 .000

8 6 9 2 .939

696 2 .843

1 7 5 1 3 .243

9 7 1 .987

265 2 .423

1 3 5 2 .130

1 9 8 5 3 .298

1 2 1 4 3.084

1 5 5 7 3 .192

50 1 .699

766 2 .884

48 1 . 6 8 1

57 1 . 8 2 6

1 2 1 .079

0 0 .000

0 0 .000

0 0 .000

5 9 5 2 .775

0 0 .000

3 RD

0 0 .000

7 4 1 .869

372 2 .571

1 6 7 2 .223

291 2 .464

0 0 .000

1 7 5 2 .243

0 0 .000

7 6 1 2 .881

574 2 .759

476 2 .678

0 0 .000

111 2 . 0 4 5

3 2 1 . 5 0 5

0 0 .000

3 .477

0 0 .000

9 5 1 .978

4 0 3 2 . 6 0 5

59 1 . 7 7 1

2 3 1 2 .364

4TH

0 0 .000

0 0 .000

200 2 . 3 0 1

1 4 6 2 .164

1 1 5 9 3.064

1 2 3 2 .090

20 1 . 3 0 1

0 0 .000

2156 3 .334

59 1 . 7 7 1

1 4 7 2 .167

1 0 1 .000

6 2 1 2 .793

47 1 .672

0 0 .000

0 0 .000

3 .477

3 18 2 .502

94 1 . 9 7 3

1 0 1 2 .004

98 1 . 9 9 1

5TH

0 0 .000

0 0 .000

1 0 0 7 3 . 0 0 3

270 2 .431

1 5 0 5 3 .178

27 1 . 4 3 1

8 5 1 . 9 2 9

0 0 .000

2492 3 .397

1 1 0 0 3 .041

6 9 3 2 .841

36 1 . 5 5 6

264 2 .422

9 .954

38 1 . 5 8 0

26 1 . 4 1 5

11 1 . 0 4 1

7 . 8 4 5

1 7 1 . 2 3 0

0 0 .000

1 6 6 2 .220

6TH

0 0 .000

0 0 .000

1 2 7 2 .104

3 1 3 2 .496

1 2 0 5 3 .081

0 0 .000

0 0 .000

0 0 .000

4146 3 .618

2944 3 .469

9 6 1 . 9 8 2

0 0 .000

0 0 .000

4 . 602

9 1 1 . 9 5 9

1 2 1 2 . 0 8 3

0 0 .000

0 0 .000

0 0 .000

20 1 . 3 0 1

0 0 .000

SUM

11 1 . 0 4 1

74 1 . 8 6 9

2714 3 .434

1760 3 .246

6 6 5 8 3 . 8 2 3

2 47 2 .393

557 2 .746

2 0 5 2 .312 11577 4 .064

5936 3 .773

3027 3 . 4 8 1

9 6 1 .982

1 9 6 7 3 .294

1 4 0 2 .146

1150 3 .061

1 7 3 2 . 2 3 8

1 4 1 . 1 4 6

1094 3 .039

1 0 6 8 3 .029

7 7 5 2 .889

1 2 0 2 3 .080

APPENDIX 5 . 2



FL 206 2 . 3 1 4

FO 6 6 8 2 . 8 2 5

FR 4 2 1 2 . 6 2 4

FS 0 0 . 0 0 0

FT 0 0 . 0 0 0

FU 318 2 . 5 0 2

FW 0 0 . 0 0 0

FY 0 0 . 0 0 0

GA 1 5 7 2 . 1 9 6

G D 0 0 . 0 0 0

G E 9 1 0 2 . 9 5 9

G G 0 0 . 0 0 0

G H 6 . 7 7 8

G I 1 5 1 . 1 7 6

G L 1 1 7 2 . 0 6 8

GM 0 0 . 0 0 0

G N 4 . 6 0 2

G O 25 1 . 3 9 8

G R 7 0 8 2 . 8 5 0

GS 0 0 . 0 0 0

GT 0 0 . 0 0 0

2ND

0 0 . 0 0 0

0 0 . 0 0 0

28 1 . 4 4 7

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

0 0 .000

0 0 .000

6 2 6 2 . 7 9 7

0 0 . 0 0 0

0 0 .000

0 0 . 0 0 0

0 0 . 0 0 0

3 . 4 7 7

0 0 .000

0 0 . 0 0 0

34 1 . 5 3 1

0 0 . 0 0 0

0 0 . 0 0 0

0 0 .000

0 0 .000

3RD

29 1 . 4 6 2

161 2 . 2 0 7

1 0 1 . 0 0 0

0 0 .000

7 6 1 . 8 8 1

9 8 1 . 9 9 1

0 0 .000

0 0 . 0 0 0

1 0 7 2 . 0 2 9

0 0 . 0 0 0

8 9 1 . 9 4 9

1 4 4 2 .158

2 2 1 2 .344

1 2 0 2 . 0 7 9

3 6 1 2 . 5 5 8

1 9 1 . 2 7 9

7 1 1 . 8 5 1

0 0 .000

94 1 . 9 7 3

0 0 . 0 0 0

0 0 .000

4TH

1 9 1 . 2 7 9

1 3 7 2 . 1 3 7

0 0 . 0 0 0

0 0 . 0 0 0

5 5 1 . 7 4 0

19 1 . 2 7 9

18 1 . 2 5 5

0 0 . 0 0 0

4 7 1 . 6 7 2

26 1 .415

4 2 9 2 . 6 3 2

4 3 1 . 6 3 3

1 6 1 2 .207

327 2 . 5 1 5

5 6 1 . 7 4 8

0 0 . 0 0 0

0 0 . 0 0 0

4 . 6 0 2

4 1 6 2 . 6 1 9

0 0 . 0 0 0

3 4 1 . 5 3 1

5TH

7 2 1 . 8 5 7

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

8 . 9 0 3

1 8 8 2 . 2 7 4

0 0 . 0 0 0

0 0 . 0 0 0

1 8 1 . 2 5 5

0 0 . 0 0 0

7 6 8 2 . 8 8 5

0 0 . 0 0 0

9 07 2 . 9 5 8

46 1 . 6 6 3

0 0 . 0 0 0

0 0 . 0 0 0

4 1 1 . 6 1 3

0 0 . 0 0 0

0 11.000

4 . 6 0 2

0 0 . 0 0 0

6TH

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

2 3 1 . 3 6 2

0 0 . 0 0 0

0 0 .000

0 0 . 0 0 0

8 9 1 . 9 4 9

2 1 1 . 3 2 2

0 0 . 0 0 0

9 2 7 2 .967

0 0 . 0 0 0

974 2 . 9 8 9

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

1 5 8 2 . 1 9 9

1 0 6 2 . 0 2 5

0 0 . 0 0 0

1 0 2 2 . 0 0 9

0 0 . 0 0 0

2 2 9

S U M

3 2 6 2 . 5 1 3

9 6 6 2 . 9 8 5

459 2 . 6 6 2

2 3 1 . 3 6 2

1 3 9 2 . 1 4 3

6 2 3 2 . 7 9 4

1 8 1 . 2 5 5

8 9 1 . 9 4 9

9 7 6 2 .989

2 5 1 . 4 1 5

3 1 2 3 3 . 4 9 5

1 8 7 2 . 2 7 2

2269 3 .356

5 1 1 2 . 7 0 8

5 3 4 2 .728

1 9 1 . 2 7 9

3 0 8 2 . 4 8 9

1 3 5 2 . 1 3 0

1 2 1 8 3 . 0 8 6

1 0 6 2 . 0 2 5

3 4 1 . 5 3 1

230 CHAPTER 5


BIGRAM POSITION 1ST

GU 40 1 . 6 0 2

G Y 0 0 . 0 0 0

H A 4 2 7 2 . 6 3 0

H E 5 0 5 2 . 7 0 3

HF 0 0 . 0 0 0

H I 1 0 3 3 3 .014

H L 0 0 . 0 0 0

HM 0 0 . 0 0 0

H N 0 0 .000

H O 8 6 3 2 .936

HR 0 0 .000

HS 0 0 . 0 0 0

HT 0 0 .000

H U 4 0 1 2 . 6 0 3

HW 0 0 . 0 0 0

HY 3 . 4 7 7

I A 0 0 . 0 0 0

I B 0 0 . 0 0 0

I C 0 0 . 0 0 0

I D 1 7 1 . 2 3 0

I E 0 0 . 0 0 0

2ND

0 0 .000

0 0 . 0 0 0

8 8 4 2 .946

7 8 1 2 . 8 9 3

0 0 . 0 0 0

3 8 5 2 . 5 8 5

0 0 .000

0 0 . 0 0 0

0 0 . 0 0 0

7 6 1 2 . 8 8 1

1 0 5 3 3 .022

0 0 . 0 0 0

0 0 .000

27 1 . 4 3 1

0 0 . 0 0 0

7 2 1 . 8 5 7

5 5 1 . 7 4 0

2 0 3 2 .307

526 2 . 7 2 1

57 1 . 7 5 6

4 1 1 . 6 1 3

3RD

2 6 7 2 . 4 2 1

0 0 .000

6 7 1 . 8 2 6

1 9 1 . 2 7 9

0 0 . 0 0 0

1 4 8 2 .170

9 . 9 5 4

0 0 . 0 0 0

3 4 1 . 5 3 1

217 2 .336

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

7 . 8 4 5

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

40 1 . 6 0 2

2 8 8 2 . 4 5 9

1 0 8 2 . 0 3 3

446 2 . 6 4 9

4TH

2 1 1 . 3 2 2

0 0 .000

3 9 7 2 .599

1 5 5 2 . 1 9 0

9 . 9 5 4

7 3 1 2 .864

0 0 .000

0 0 .000

0 0 . 0 0 0

7 9 4 2 . 9 0 0

0 0 . 0 0 0

0 0 . 0 0 0

1 1 7 2 . 0 6 8

0 0 . 0 0 0

4 0 1 . 6 0 2

0 0 . 0 0 0

7 9 1 . 8 9 8

8 5 1 . 9 2 9

8 8 8 2 . 9 4 8

4 3 2 2 . 6 3 5

8 5 3 2 . 9 3 1

5TH

1 9 1 . 2 7 9

0 0 . 0 0 0

3 2 1 . 5 0 5

2568 3 . 4 1 0

0 0 . 0 0 0

56 1 . 7 4 8

5 8 1 . 7 6 3

1 2 1 . 0 7 9

0 0 . 0 0 0

8 5 1 . 9 2 9

0 0 . 0 0 0

0 0 . 0 0 0

6 0 1 . 7 7 8

3 . 4 7 7

0 0 . 0 0 0

0 0 . 0 0 0

7 1 9 2 . 8 5 7

0 0 . 0 0 0

7 9 4 2 . 9 0 0

4 9 8 2 . 6 9 7

1 3 2 3 3 .122

6TH

0 0 . 0 0 0

3 5 1 . 5 4 4

0 0 . 0 0 0

3 2 1 . 5 0 5

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

26 1 . 4 1 5

9 0 7 2 . 9 5 8

0 0 . 0 0 0

0 0 . 0 0 0

7 0 1 . 8 4 5

7 6 1 . 8 8 1

0 0 . 0 0 0

350 2 . 5 4 4

4 9 1 . 6 9 0

6 9 1 . 8 3 9

SUM

3 4 7 2 . 5 4 0

3 5 1 . 5 4 4

1 8 0 7 3 . 2 5 7

4 0 6 0 3 . 6 0 9

9 . 9 5 4 2 3 5 3

3 . 3 7 2 6 7

1 . 8 2 6 1 2

1 . 0 7 9 3 4

1 . 5 3 1 2 7 2 0

3 . 4 3 5 1 0 5 3

3 . 0 2 2 2 6

1 . 4 1 5 1 0 8 4

3 . 0 3 5 4 38

2 . 6 4 1 40

1 . 6 0 2 1 4 5

2 . 1 6 1 9 2 9

2 . 9 6 8 3 2 8

2 . 5 1 6 2846

3 . 4 5 4 1 1 6 1

3 . 0 6 5 2 7 3 2

3 .436

APPENDIX 5.2



I F 0 0 . 0 0 0

I G 34 1 . 5 3 1

I K 0 0 . 0 0 0

I L 32 1 . 5 0 5

I M 2 4 9 2 . 3 9 6

I N 8 2 5 2 . 9 1 6

I 0 0 0 . 0 0 0

I P 0 0 . 0 0 0

I Q 0 0 . 0 0 0

I R 18 1 . 2 5 5

I S 42 1 . 6 2 3

I T 5 1 1 . 7 0 8

I U 0 0 . 0 0 0

I V 0 0 .000

I X 0 0 . 0 0 0

I 2 0 0 . 0 0 0

J A 111 2 . 0 4 5

J E 1 9 1 . 2 7 9

J O 1 3 0 2 . 1 1 4

J U 2 1 1 2 .324

K A 2 1 1 . 3 2 2

2ND

9 0 1 . 9 5 4

489 2 . 6 8 9

3 . 4 7 7

7 9 1 2 . 8 9 8

8 9 9 2 . 9 5 4

1 0 6 8 3 . 0 2 9

6 7 1 . 8 2 6

1 6 1 . 2 0 4

6 .778

1 6 2 2 . 2 1 0

9 2 7 2 . 9 6 7

957 2 . 9 8 1

0 0 . 0 0 0

1 1 7 2 . 0 6 8

7 5 1 . 8 7 5

22 1 . 3 4 2

0 0 . 0 0 0

0 0 . 0 0 0

0 0 .000

0 0 .000

0 0 .000

3RD

1 2 6 2 . 1 0 0

9 8 1 . 9 9 1

0 0 .000

429 2 . 6 3 2

280 2 .447

538 2 . 7 3 1

24 1 . 3 8 0

1 0 0 2 . 0 0 0

0 0 .000

8 0 1 . 9 0 3

1 9 2 2 . 2 8 3

9 7 6 2 .989

22 1 . 3 4 2

2 9 1 2 . 4 6 4

0 0 . 0 0 0

1 5 1 . 1 7 6

3 . 4 7 7

7 6 1 . 8 8 1

6 2 1 . 7 9 2

26 1 . 4 1 5

4 . 6 0 2

4TH 5TH 6TH

3 8 9 3 0 1 . 5 8 0 1 . 9 6 8 0 . 0 0 0

1 9 5 161 0 2 . 2 9 0 2 . 2 0 7 0 . 0 0 0

20 1 9 7 1 . 3 0 1 1 . 2 7 9 . 8 4 5

2 0 1 3 9 3 1 2 6 2 . 3 0 3 2 . 5 9 4 2 . 1 0 0

2 5 2 5 2 1 9 2 . 4 0 1 1 . 7 1 6 1 . 2 7 9

9 4 1 7 7 8 7 5 8 2 2 . 9 7 4 3 . 8 9 1 2 .834

9 3 3 1 3 5 1 6 2 . 9 7 0 3 . 1 3 1 . 7 7 8

1 0 4 39 1 . 0 0 0 . 6 0 2 1 . 5 9 1

1 2 0 0 1 . 0 7 9 0 . 0 0 0 0 . 0 0 0

1 6 6 264 2 1 2 . 2 2 0 2 . 4 2 2 1 . 3 2 2

220 7 0 4 47 2 . 3 4 2 2 . 8 4 8 1 . 6 7 2

4 1 9 6 3 6 2 3 5 2 . 6 2 2 2 . 8 0 3 2 . 3 7 1

0 4 8 0 0 . 0 0 0 1 . 6 8 1 0 . 0 0 0

2 1 6 1 9 0 0 2 . 3 3 4 2 . 2 7 9 0 . 0 0 0

1 4 0 9 1 . 1 4 6 0 . 0 0 0 . 9 5 4

5 7 1 . 7 5 6

0 0 . 0 0 0

2 54 2 . 4 0 5

0 0 . 0 0 0

0 0 . 0 0 0

2 0 1 . 3 0 1

7 9 0 1 . 8 9 8 0 . 0 0 0

0 0 0 . 0 0 0 0 . 0 0 0

0 0 0 . 0 0 0 0 . 0 0 0

0 0 0 . 0 0 0 0 . 0 0 0

0 0 0 . 0 0 0 0 . 0 0 0

0 0 0 .000 0 . 0 0 0

2 3 1

SUM

347 2 . 5 4 0

977 2 . 9 9 0

4 9 1 . 6 9 0

1 9 7 2 3 . 2 9 5

1 7 5 1 3 . 2 4 3 1 1 8 4 1 4 . 0 7 3

2 3 8 1 3 . 3 7 7

1 6 9 2 . 2 2 8

18 1 . 2 5 5

7 1 1 2 . 8 5 2

2 1 3 2 3 . 3 2 9

3274 3 . 5 1 5

7 0 1 . 8 4 5

8 1 4 2 . 9 1 1

9 8 1 . 9 9 1

1 7 3 2 . 2 3 8

1 1 4 2 . 0 5 7

349 2 . 5 4 3

1 9 2 2 . 2 8 3

237 2 . 3 7 5

4 5 1 . 6 5 3

232 CHAPTER 5


BIGRAM POSITION 1ST

K E 2 1 3 2 . 3 2 8

K I 1 8 3 2 .262

KL 0 0 .000

K M 0 0 .000

K N 1 0 4 2 .017

K O 0 0 .000

KP 0 0 .000

K R 11 1 . 0 4 1

KS 0 0 .000

K U 0 0 .000

KW 0 0 .000

K Y 0 0 .000

LA 3 1 2 2 . 4 9 4

L B 0 0 .000

LC 0 0 . 0 0 0

L D 0 0 . 0 0 0

L E 7 0 6

LF 0 0 . 0 0 0

LG 0 0 . 0 0 0

L H 0 0 . 0 0 0

L I 497 2 . 6 9 6

2 .849

2ND

0 0 .000

4 3 1 . 6 3 3

0 0 .000

0 0 .000

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

0 0 .000

0 0 . 0 0 0

0 0 . 0 0 0

5 . 6 9 9

8 9 0 2 . 9 4 9

0 0 .000

1 3 1 . 1 1 4

1 3 1 . 1 1 4

429 2 . 6 3 2

0 0 .000

0 0 .000

0 0 . 0 0 0

2 1 9 2 . 3 4 0

3RD

3 . 4 7 7

4 . 6 0 2

0 0 . 0 0 0

0 0 . 0 0 0

4 7 1 . 6 7 2

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

11 1 . 0 4 1

0 0 . 0 0 0

3 4 1 2 . 5 3 3

3 . 4 7 7

7 3 1 . 8 6 3

1 3 5 2 . 1 3 0

2 2 6 2 . 3 5 4

88 1 . 9 4 4

2 1 1 . 3 2 2

1 4 1 . 1 4 6

3 7 8 2 . 5 7 7

4TH 5TH

2 7 6 3 94 2 . 4 4 1 2 . 5 9 5

8 9 8 0 2 . 9 5 3 0 . 0 0 0

3 1 2 7 . 4 7 7 2 . 1 0 4

7 0

0 0 0 . 0 0 0 0 . 0 0 0

1 5 0 1 . 1 7 6 0 . 0 0 0

1 6 0 1 . 2 0 4 0 . 0 0 0

0 0 0 . 0 0 0 0 . 0 0 0

3 9 0 1 . 5 9 1 0 . 0 0 0

0 3 0 . 0 0 0 . 4 7 7

6 0 . 7 7 8 0 . 0 0 0

0 0 0 . 0 0 0 0 . 0 0 0

. a 4 5 0 . 0 0 0

5 2 5 4 6 5 2 . 7 2 0 2 . 6 6 7

0 0 0 . 0 0 0 0 . 0 0 0

0 0 0 . 0 0 0 0 . 0 0 0

7 1 0 1 . 8 5 1 0 . 0 0 0

6 6 1 1 4 7 8 2 .820 3 . 1 7 0

5 0 . 6 9 9 0 . 0 0 0

0 9 0 . 0 0 0 . 9 5 4

0 0 0 . 0 0 0 0 . 0 0 0

2 3 8 0 7 3 3 . 3 7 7 1 . 8 6 3

6TH SUM

5 6 9 4 2 1 . 7 4 8 2 . 9 7 4

0 1 1 2 8 0 . 0 0 0 3 . 0 5 2

0 1 3 0 0 . 0 0 0 2 . 1 1 4

0 7 0 . 0 0 0 . 8 4 5

0 1 5 1 0 . 0 0 0 2 . 1 7 9

0 1 5 0 . 0 0 0 1 . 1 7 6

0 1 6 0 . 0 0 0 1 . 2 0 4

0 11 0 . 0 0 0 1 . 0 4 1

81 1 2 0 1 . 9 0 8 2 . 0 7 9

0 3 0 . 0 0 0 . 4 7 7

0 1 7 0 . 0 0 0 1 . 2 3 0

0 5 0 . 0 0 0 . 6 9 9

5 9 2 5 9 2 1 . 7 7 1 3 . 4 1 4

0 3 0 . 0 0 0 . 4 7 7

0 8 6 0 . 0 0 0 1 . 9 3 4

1 8 2 37 1 . 2 5 5 2 . 3 7 5

9 9 3 4 4 9 3 2 .997 3 . 6 5 3

7 3 3 8 2 6 2 . 8 6 5 2 . 9 1 7

0 3 0 0 . 0 0 0 1 . 4 7 7

0 1 4 0 . 0 0 0 1 . 1 4 6

9 3 5 5 6 . 9 5 4 3 . 5 5 1




LK 0 0 . 0 0 0

L L 0 0 . 0 0 0

LM 0 0 .000

L N 0 0 . 0 0 0

L O 429 2 . 6 3 2

LP 0 0 . 0 0 0

L R 0 0 . 0 0 0

LS 0 0 . 0 0 0

LT 0 0 . 0 0 0

LU 39 1 . 5 9 1

LV 0 0 . 0 0 0

LW 0 0 . 0 0 0

LY 7 . 8 4 5

MA 9 0 1 2 . 9 5 5

MB 0 0 . 0 0 0

ME 1 2 2 2 3 . 0 8 7

MF 0 0 . 0 0 0

M I 8 3 3 2 . 9 2 1

ML 0 0 . 0 0 0

M M 0 0 . 0 0 0

MN 0 0 . 0 0 0

2ND

0 0 .000

1 3 3 2 . 1 2 4

0 0 . 0 0 0

0 0 . 0 0 0

4 2 5 2 . 6 2 8

0 0 . 0 0 0

2 7 3 2 . 4 3 6

0 0 .000

22 1 . 3 4 2

8 7 1 . 9 4 0

4 . 6 0 2

0 0 .000

1 6 1 . 2 0 4

213 2 . 3 2 8

3 0 1 . 4 7 7

2 7 3 2 . 4 3 6

0 0 . 0 0 0

7 8 1 . 8 9 2

0 0 . 0 0 0

1 9 1 . 2 7 9

0 0 .000

3RD 4TH 5TH 6TH

1 5 4 7 0 0 2 . 1 8 8 . 8 4 5 0 . 0 0 0 0 . 0 0 0

1 5 2 8 2 0 9 5 6 9 1 1 0 3 .184 2 . 3 2 0 2 . 7 5 5 2 . 0 4 1

4 0 0 7 - 6 0 2 0 . 0 0 0 0 . 0 0 0 . 8 4 5

2 5 0 0 47 1 . 3 9 8 0 . 0 0 0 0 . 0 0 0 1 . 6 7 2

2 2 5 2 8 8 1 1 3 1 6 2 .352 2 .459 2 . 0 5 3 1 . 2 0 4

7 6 0 0 0 1 . 8 8 1 0 . 0 0 0 0 . 0 0 0 0 . 0 0 0

0 0 3 5 0 0 . 0 0 0 0 . 0 0 0 1 . 5 4 4 0 .000

1 3 0 253 484 1 . 1 1 4 0 . 0 0 0 1 . 3 0 1 2 . 6 8 5

1 0 7 1 3 3 292 3 3 2 .029 2 . 1 2 4 2 . 4 6 5 1 . 5 1 9

9 2 214 27 0 1 . 9 6 4 2 . 3 3 0 1 . 4 3 1 0 .000

1 3 1 6 44 0 1 . 1 1 4 1 . 2 0 4 1 . 6 4 3 0 . 0 0 0

5 1 9 0 0 . 6 9 9 1 . 2 7 9 0 . 0 0 0 0 . 0 0 0

5 1 7 0 1 9 2 4 . 6 9 9 1 . 2 3 0 0 . 0 0 0 3 . 2 8 4

235 4 4 0 1 6 2 5 8 2 . 3 7 1 2 . 6 4 3 2 . 2 1 0 1 . 7 6 3

5 6 1 1 1 4 7 0 2 . 7 4 9 2 . 0 5 7 . 8 4 5 0 . 0 0 0

2 5 1 2 4 1 4 4 2 246 2 . 4 0 0 2 . 3 8 2 2 . 6 4 5 2 .391

4 3 4 0 0 1 . 6 3 3 . 6 0 2 0 . 0 0 0 0 .000

306 2 9 7 3 5 0 2 . 4 8 6 2 . 4 7 3 1 . 5 4 4 0 . 0 0 0

5 11 0 0 . 6 9 9 1 . 0 4 1 0 . 0 0 0 0 . 0 0 0

1 7 7 3 8 2 5 0 2 . 2 4 8 1 . 5 8 0 1 . 3 9 8 0 . 0 0 0

0 7 3 6 1 3 0 . 0 0 0 . 8 4 5 1 . 5 5 6 1 . 1 1 4

S U M

1 6 1 2 . 2 0 7

2 5 4 9 3 . 4 0 6

11 1 . 0 4 1

7 2 1 . 8 5 7

1 4 9 6 3 . 1 7 5

7 6 1 . 8 8 1

3 0 8 2 . 4 8 9

5 1 7 2 . 7 1 3

587 2 . 7 6 9

4 59 2 . 6 6 2

7 7 1 . 8 8 6

24 1 . 3 8 0

1 9 6 9 3 . 2 9 4

2009 3 . 3 0 3

7 1 2 2 . 8 5 2

2 6 7 5 3 . 4 2 7

47 1 . 6 7 2

1 5 4 9 3 .190

1 6 1 . 2 0 4

2 59 2 . 4 1 3

56 1 . 7 4 8

234 CHAPTER 5


BIGRAM POSITION 1ST

M O 471 2 , 6 7 3

MP 0 0 .000

MR 0 0 .000

MS 0 0 .000

MU 1 8 0 2 . 2 5 5

MY 42 1 . 6 2 3

NA 358 2 .554

N B 0 0 .000

N C 0 0 .000

N D 0 0 .000

N E 394 2 .595

NF 0 0 .000

N G 0 0 .000

N H 0 0 .000

N I 3 .477

N J 0 0 .000

N K 0 0 .000

N L 0 0 .000

NM 0 0 .000

N N 0 0 .000

N O 5 8 5 2 .767

2ND

90 1 . 9 5 4

1 9 7 2 .294

0 0 .000

0 0 .000

1 7 1 .230

0 0 .000

1 3 1 2 .117

3 . 477

1 9 5 2 .290

1 2 7 2 .104

38 1 .580

3 6 1 .556

498 2 .697

50 1 . 6 9 9

220 2 .342

77 1 .886

47 1 . 6 7 2

7 . 8 4 5

9 .954

1 5 1 . 1 7 6

782 2 . 8 9 3

3RD

1 3 6 2 .134

6 0 2 2 .780

4 . 602 6 0 3

2 .780 0

0 .000 0

0 .000 476

2 .678 0

0 .000 448

2 .651 596

2 .775 7 1 8

2 .856 5 5

1 .740 3 29

2 .517 6

. 7 7 8 1 9 3

2 .286 0

0 .000 1 1 5

2 . 0 6 1 3

. 477 4

. 6 0 2 373

2 .572 1 5 0

2 .176

4TH

1 4 5 2 .161

348 2 .542

0 0 .000

8 . 9 0 3

7 7 1 . 8 8 6

0 0 .000

8 1 1 . 9 0 8

1 3 1 .114

228 2.358

244 2 .387

4 24 2 .627

2 5 1 .398

309 2 .490

0 0 .000

1 2 3 1 3 .090

0 0 .000

7 3 1 . 8 6 3

3 5 1 . 5 4 4

0 0 .000

1 4 9 2 .173

1 4 2 2 . 1 5 2

5TH

0 0 .000

1 1 7 2 .068

0 0 .000

0 0 .000

1 5 9 2 . 2 0 1

0 0 .000

9 2 1 .964

0 0 .000

509 2 .707

450 2 .653

638 2 .805

0 0 .000

230 2 .362

0 0 .000

8 7 1 . 9 4 0

0 0 .000

0 0 .000

2 1 1 . 3 2 2

0 0 .000

3 2 1 . 5 0 5

1 0 1 . 0 0 0

6TH S U M

0 8 4 2 0 .000 2 . 9 2 5

0 1 2 6 4 0 .000 3 . 1 0 2

0 4 0 .000 . 6 0 2

227 8 3 8 2 .356 2 . 9 2 3

0 4 3 3 0 .000 2 .636

1 1 2 1 5 4 2 . 0 4 9 2 .188

38 1 1 7 6 1 . 5 8 0 3 .070

0 1 6 0 .000 1 . 2 0 4

0 1 3 8 0 0 .000 3 .140

530 1 9 4 7 2 .724 3 .289

502 2714 2 .701 3 .434

0 1 1 6 0 .000 2 .064

7212 8578 3 .858 3 . 9 3 3

0 56 0 .000 1 . 7 4 8

9 1 7 4 3 .954 3 . 2 4 1

0 7 7 0 .000 1 . 8 8 6

0 2 3 5 0 .000 2 . 3 7 1

0 6 6 0 .000 1 .820

0 1 3 0 .000 1 . 1 1 4

0 559 0 .000 2 .755

1 0 1 6 7 9 1 . 0 0 0 3 .225

APPENDIX 5 . 2



NQ 0 0 . 0 0 0

N R 0 0 . 0 0 0

NS 0 0 . 0 0 0

NT 0 0 . 0 0 0

N U 288 2 . 4 5 9

NV 0 0 . 0 0 0

N X 0 0 . 0 0 0

NY 0 0 . 0 0 0

N Z 0 0 . 0 0 0

OA 0 0 . 0 0 0

OB 229 2 . 3 6 0

oc 5 1 1 . 7 0 8

OD 0 0 . 0 0 0

O E 0 0 . 0 0 0

OF 237 2 . 3 7 5

OG 0 0 . 0 0 0

O H 0 0 . 0 0 0

01 0 0 . 0 0 0

OJ 0 0 . 0 0 0

O K 0 0 . 0 0 0

OL 7 . 8 4 5

2ND

2 8 1 . 4 4 7

3 .477

3 57 2 . 5 5 3

242 2 . 3 8 4

6 9 1 . 8 3 9

8 8 1 . 9 4 4

7 1 1 . 8 5 1

46 1 . 6 6 3

11 1 . 0 4 1

1 3 0 2 .114

8 7 1 . 9 4 0

460 2 . 6 6 3

4 3 1 . 6 3 3

0 0 .000

0 0 .000

39 1 . 5 9 1

3 4 1 . 5 3 1

1 1 5 2 . 0 6 1

5 . 6 9 9

0 0 .000

8 8 8 2 . 9 4 8

3 RD

1 0 1 . 0 0 0

1 0 1 . 0 0 0

2 38 2 . 3 7 7

1 1 1 0 3 . 0 4 5

2 9 3 2 . 4 6 7

29 1 . 4 6 2

0 0 .000

1 0 1 . 0 0 0

0 0 . 0 0 0

47 1 . 6 7 2

318 2 . 5 0 2

295 2 . 4 7 0

1 8 5 2 .267

22 1 . 3 4 2

4 8 1 . 6 8 1

3 9 9 2 . 6 0 1

0 0 . 0 0 0

37 1 . 5 6 8

9 3 1 . 9 6 8

230 2 . 3 6 2

1 6 2 2 . 2 1 0

4TH

0 0 . 0 0 0

0 0 . 0 0 0

8 9 1 . 9 4 9

7 3 2 2 . 8 6 5

1 0 1 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

1 2 1 . 0 7 9

5 1 1 . 7 0 8

5 . 6 9 9

1 4 1 . 1 4 6

0 0 . 0 0 0

7 . 8 4 5

9 . 9 5 4

1 3 1 . 1 1 4

2 7 1 . 4 3 1

0 0 . 0 0 0

24 1 . 3 8 0

7 0 1 . 8 4 5

5TH

0 0 . 0 0 0

6 . 7 7 8 9 4 6

2 . 9 7 6 3 3 2

2 . 5 2 1 4 2

1 . 6 2 3 0

0 . 0 0 0 0

0 . 0 0 0 3

. 4 7 7 3

. 4 7 7 0

0 . 0 0 0 0

0 . 0 0 0 8

. 9 0 3 2 4 9

2 . 3 9 6 5 8

1 . 7 6 3 0

0 . 0 0 a 2 9

1 . 4 6 2 0

0 . 0 0 0 8 0

1 . 9 0 3 0

0 . 0 0 0 3

. 4 7 7 3 2 9

2 . 5 1 7

6T9

0 0 . 0 0 0

0 0 . 0 0 0

1 1 9 7 3 . 0 7 8

1 6 5 3 3 . 2 1 8

0 0 . 0 0 0

0 0 . 0 0 0

5 . 6 9 9

467 2 . 6 6 9

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

2 5 1 . 3 9 8

0 0 . 0 0 0

1 6 1 . 2 0 4

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

3 6 1 . 5 5 6

264 2 . 4 2 2

2 3 5

SUM

3 8 1 . 5 8 0

1 9 1 . 2 7 9

2 8 2 7 3 . 4 5 1

4069 3 . 6 0 9

7 0 2 2 . 8 4 6

1 1 7 2 . 0 6 8

7 6 1 . 8 8 1

526 2 . 7 2 1

1 4 1 . 1 4 6

1 8 9 2 . 2 7 6

6 8 5 2 . 8 3 6

8 1 9 2 . 9 1 3

516 2 . 7 1 3

8 0 1 . 9 0 3

3 0 8 2 . 4 8 9

476 2 . 6 7 8

47 1 . 6 7 2

2 59 2 . 4 1 3

9 8 1 9 9 1

2 9 3 2 4 6 7

7 2 0 3 236

2 36 CHAPTER 5


BIGRAM POSITION 1ST 2ND 3RD 4TH 5TH 6TH

OM 25 1 .398

ON 5 . 699

00 0 0 .000

OP 3 3 1 2 .520

OQ 0 0 .000

OR 200 2 .301

0s 0 0 .000

OT 0 0 .000

ou 3 4 3 2 .535

ov 24 1 . 3 8 0

ow 0 0 .000

ox 0 0 .000

OY 8 . 9 0 3

PA 949 2 .977

PD 0 0 .000

PE 810 2.908

PF 0 0 .000

PG 0 0 .000

PH 57 1 .756

P I 317 2 .501

PK 0 0 .000

942 2.974

1 0 4 4 3 .019

356 2 .551

1 4 0 2 .146

0 0 .000

1 3 3 7 3 .126

99 1 . 9 9 6

704 2 .848

1 3 4 8 3 .130

1 6 4 2 .215

6 8 1 2 .833

0 0 .000

5 1 1 . 7 0 8

59 1 . 7 7 1

3 .477

508 2 .706

0 0 .000

3 .477

4 . 602

1 6 0 2 .204

0 0.000

1 3 3 2 .124

1 4 3 2 .155

5 5 1 . 7 4 0

379 2 .579

0 0 .000

274 2 .438

1 8 7 2 , 2 7 2

1 0 2 3 3 .010

1 1 0 8 3 .045

238 2 .377

413 2 .616

0 0 .000

3 . 477

7 9 1 .898

0 0 .000

3 79 2 .579

0 0 .000

0 0 .000

3 .477

2 6 5 2 .423

7 . 845

1 2 5 2.097

1 5 0 2 .176

208 2 .318

2 1 1 . 3 2 2

11 1 . 0 4 1

526 2 .721

1 1 5 2 . 0 6 1

8 2 1 . 9 1 4

1 1 0 1 3 .042

2 29 2 .360

98 1 . 9 9 1

0 0 .000

64 1 .806

4 03 2 .605

0 0 .000

2 6 3 2 .420

29 1 . 4 6 2

0 0 .000

40 1 . 6 0 2

382 2 .582

0 0 .000

1 9 4 2 .288

92 5 2 .966

1 5 3 2 .185

6 . 778

0 0 .000

1 1 0 5 3 . 0 4 3

278 2 .444

57 1 . 7 5 6

1 2 6 1 3 .101

5 3 1 . 7 2 4

2 4 5 2 .389

0 0 .000

1 3 1 .114

0 0 .000

0 0 .000

571 2 .757

0 0 .000

0 0 .000

0 0 .000

2 3 1 . 3 6 2

0 0 .000

229 2 .360

1664 3 .221

0 0 .000

8 9 1 . 9 4 9

0 0 .000

1 9 5 2 .290

0 0 .000

1 3 1 . 1 1 4

0 0 .000

0 0 .000

1 1 2 2 .049

9 . 954

4 8 1 . 6 8 1

0 0 .000

0 0 .000

0 0 .000

0 0 . 0 0 0

0 0 .000

22 1 . 3 4 2

0 0 .000

0 0.000

SUM

1 6 4 8 3 . 2 1 7

3 9 3 1 3 .595

772 2 .888

966 2 . 9 8 5

11 1 . 0 4 1

3637 3 . 5 6 1

6 7 9 2 .832

1 8 7 9 3 .274

5161 3 .713

7 08 2 .850

1 5 4 9 3 .190

9 .954

1 8 7 2 .272

1490 3 .173

3 . 477 2531

3 .403 29

1 . 4 6 2 3

. 477 1 2 6

2 .100 1 1 4 7

3 .060 7

. 8 4 5

APPENDIX 5 . 2


BIGRAM POSITION 1ST

PL 468 2 . 6 7 0

PM 0 0 . 0 0 0

PO 412 2 . 6 1 5

PP 0 0 . 0 0 0

PR 2 7 3 0 3 . 4 3 6

PS 3 . 4 7 7

PT 0 0 . 0 0 0

PU 3 2 1 2 .507

PW 0 0 . 0 0 0

PY 0 0 . 0 0 0

QU 358 2 . 5 5 4

R A 3 1 1 2 . 4 9 3

RB 0 0 . 0 0 0

RC 0 0 . 0 0 0

RD 0 0 . 0 0 0

R E 2 7 8 1 3 .444

RF 0 0 . 0 0 0

RG 0 0 . 0 0 0

R H 1 2 1 . 0 7 9

R I 1 1 8 2 . 0 7 2

RK 0 0 . 0 0 0

2N D

0 0 . 0 0 0

0 0 .000

5 1 1 . 7 0 8

294 2 . 4 6 8

5 1 1 . 7 0 8

3 . 4 7 7

G3 1 . 7 9 9

6 . 7 7 8

6 . 7 7 8

0 0 .000

1 1 3 2 . 0 5 3

7 7 4 2 .889

5 . 6 9 9

8 . 9 0 3

9 3 1 . 9 6 8

1 4 6 3 3 . 1 6 5

0 0 .000

6 3 1 . 7 9 9

0 0 . 0 0 0

1 4 5 7 3 . 1 6 3

0 0 . 0 0 0

3RD

3 6 1 2 . 5 5 8

0 0 .000

2 2 3 2 .348

397 2 .599

1 6 6 2 .220

5 . 6 9 9

1 4 1 2 . 1 4 9

1 2 8 2 .107

0 0 .000

0 0 . 0 0 0

1 9 9 2 .299

280 2 .447

5 0 1 . 6 9 9

1 7 3 2 .238

1 0 2 2 . 0 0 9

8 7 0 2 . 9 4 0

340 2 . 5 3 1

2 1 2 2 . 3 2 6

307 2 . 4 8 7

8 5 8 2 . 9 3 3

3 5 0 2 . 5 4 4

4TH

2 8 9 2 . 4 6 1

6 .77 8

5 8 5 2 . 7 6 7

4 3 7 2 . 6 4 0

0 0 . 0 0 0

1 5 1 . 1 7 6

1 6 0 2 . 2 0 4

4 6 1 . 6 6 3

0 0 . 0 0 0

0 0 . 0 0 0

2 6 1 . 4 1 5

4 5 6 2 . 6 5 9

8 . 9 0 3

9 9 1 . 9 9 6

3 7 1 . 5 6 8

6 6 1 2 . 8 2 0

1 3 1 . 1 1 4

1 8 3 2 . 2 6 2

0 0 . 0 0 0

12c15 3 . 0 8 1

7 . 8 4 5

5TH

3 49 2 . 5 4 3

0 0 . 0 0 0

0 0 . 0 0 0

2 6 1 . 4 1 5

0 0 . 0 0 0

1 9 1 . 2 7 9

6 . 7 7 8

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

2 3 1 . 3 6 2

2 0 5 9 3 . 3 1 4

1 8 1 . 2 5 5

4 1 1 . 6 1 3

1 9 0 2 . 2 7 9

1 2 1 9 3 .086

0 0 . 0 0 0

1 8 1 . 2 5 5

0 0 . 0 0 0

7 4 1 . 8 6 9

5 3 1 . 7 2 4

6TH

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

3 1 3 2 . 4 9 6

2 0 3 2 .307

0 0 .000

0 0 .000

3 8 1 . 5 8 0

0 0 .000

3 2 1 . 5 0 5

1 5 1 . 1 7 6

0 0 .000

317 2 .501

1 0 8 7 3 .036

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

3 9 1 . 5 9 1

2 3 7

SUM

1 4 6 7 3 . 1 6 6

6 . 7 7 8 1 2 7 1

3 . 1 0 4 1 1 5 4

3 . 0 6 2 2 9 4 7

3 . 4 6 9 358

2 . 5 5 4 5 7 3

2 . 7 5 8 5 0 1

2 . 7 0 0 6

. 7 7 8 3 8

1 . 5 8 0 7 1 9

2 .857 3 9 1 2

3 . 5 9 2 9 6

1 . 9 8 2 3 2 1

2 . 5 0 7 7 3 9

2 . 8 6 9 8 0 8 1

3 .907 3 5 3

2 .548 476

2 . 6 7 8 3 1 9

2 . 5 0 4 3 7 1 2

3 . 5 7 0 4 4 9

2 . 6 5 2

238 CHAPTER 5


BIGRAM POSITION 1ST

R L 0 0 . 0 0 0

RM 0 0 .000

RN 0 0 . 0 0 0

RO 247 2 . 3 9 3

RP 0 0 .000

RQ 0 0 . 0 0 0

RR 0 0 . 0 0 0

RS 0 0 . 0 0 0

RT 0 0 . 0 0 0

RU 257 2 . 4 1 0

RV 0 0 . 0 0 0

RW 0 0 . 0 0 0

RY 0 0 . 0 0 0

S A 1 6 3 2 . 2 1 2

S B 0 0 . 0 0 0

sc 454 2 .657

SD 0 0 . 0 0 0

SE 1 6 5 5 3 . 2 1 9

SF 0 0 . 0 0 0

SH 554 2 .744

S I 569 2 . 7 5 5

2ND

40 1 . 6 0 2

3 . 4 7 7

0 0 .000

2 6 4 0 3 . 4 2 2

0 0 . 0 0 0

0 0 .000

111 2 . 0 4 5

3 . 4 7 7

1 2 3 2 .090

1 8 2 2 . 2 6 0

0 0 . 0 0 0

0 0 .000

26 1 . 4 1 5

0 0 .000

0 0 . 0 0 0

22 1 . 3 4 2

0 0 . 0 0 0

1 7 1 . 2 3 0

0 0 .000

2 3 1 . 3 6 2

0 0 . 0 0 0

3RD

1 9 9 2 .299

3 7 2 2 . 5 7 1

494 2 . 6 9 4

1 0 4 7 3 .020

2 0 7 2 . 3 1 6

4 . 6 0 2

6 3 0 2 . 7 9 9

4 59 2 . 6 6 2

8 4 2 2 . 9 2 5

5 . 6 9 9

5 0 2 2 . 7 0 1

1 4 2 2 . 1 5 2

42 1 . 6 2 3

1 5 1 . 1 7 6

1 3 1 2 . 1 1 7

1 0 4 2 . 0 1 7

3 . 4 7 7

2 4 1 2 .382

0 0 . 0 0 0

204 2 .310

416 2 .619

4TH

1 8 3 2 . 2 6 2

9 0 1 . 9 5 4

2 2 2 2 . 3 4 5

2 8 9 2 . 4 6 1

4 1 1 . 5 1 3

0 0 .000

52 1 . 7 1 6

8 6 1 . 9 3 4

3 7 3 2 . 5 7 2

2 3 1 . 3 6 2

3 . 4 7 7

1 5 1 . 1 7 6

0 0 . 0 0 0

1 2 8 2 . 1 0 7

0 0 .000

0 0 . 0 0 0

5 9 1 . 7 7 1

1 2 8 3 3 .108

0 0 . 0 0 0

1 8 9 2 . 2 7 6

1 1 5 4 3 . 0 6 2

5TH

2 1 9 2 . 3 4 0

2 0 1 . 3 0 1

4 5 1 . 6 5 3

3 0 2 2 . 4 8 0

6 . 7 7 8

0 0 . 0 0 0

7 . 8 4 5

5 3 1 . 7 2 4

3 8 8 2 . 5 8 9

5 . 6 9 9

7 4 1 . 8 6 9

0 0 . 0 0 0

0 0 . 0 0 0

1 8 1 . 2 5 5

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

7 7 7 2 . 8 9 0

1 6 1 . 2 0 4

0 0 . 0 0 0

5 8 1 . 8 3 3

6TH

0 0 .000

1 0 9 2 .037

4 50 2 . 6 5 3

4 . 6 0 2

0 0 . 0 0 0

0 0 . 0 0 0

0 0 .000

2 2 9 9 3 . 3 6 2

3 56 2 . 5 5 1

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

1 4 8 5 3 . 1 7 2

5 . 6 9 9

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

1 8 3 2 3 . 2 6 3

0 0 . 0 0 0

4 5 5 2 .658

0 0 . 0 0 0

SUM

6 4 1 2 .807

594 2 . 7 7 4

1 2 1 1 3 . 0 8 3

4 5 2 9 3 . 6 5 6

254 2 . 4 0 5

4 . 6 0 2

8 0 0 2 . 9 0 3

2 9 0 0 3 . 4 6 2

2 0 8 2 3 . 3 1 8

472 2 .674

5 7 9 2 . 7 6 3

1 5 7 2 . 1 9 6

1 5 5 3 3 . 1 9 1

329 2 . 5 1 7

1 3 1 2 . 1 1 7

580 2 . 7 6 3

6 2 1 . 7 9 2

5 8 0 5 3 . 7 6 4

1 6 1 . 2 0 4

1 4 2 5 3 . 1 5 4

2207 3 . 3 4 4

APPENDIX 5.2


BIGRAM POSITION 1ST

SK 48 1 . 6 8 1

SL 1 8 6 2 . 2 7 0

SM 1 6 0 2 . 2 0 4

SN 56 1 . 7 4 8

S O 6 6 5 2 . 8 2 3

S P 586 2 . 7 6 8

SQ 29 1 . 4 6 2

S R 0 0 . 0 0 0

SS 0 0 . 0 0 0

ST 1 5 8 6 3 . 2 0 0

SU 1 1 2 4 3 . 0 5 1

sw 84 1 . 9 2 4

SY 1 7 3 2 . 2 3 8

TA 2 0 3 2 . 3 0 7

TB 0 0 . 0 0 0

TC 0 0 .000

TD 0 0 . 0 0 0

TE 374 2 .573

TF 0 0 . 0 0 0

TG 0 0 .000

TH 1 8 1 3 3 . 2 5 8

2ND

0 0 .000

30 1 . 4 7 7

0 0 . 0 0 0

0 0 .000

8 . 9 0 3

7 0 1 . 8 4 5

3 . 4 7 7

0 0 . 0 0 0

1 6 8 2 . 2 2 5

8 . 9 0 3

206 2 .314

0 0 . 0 0 0

3 . 4 7 7

584 2 . 7 6 6

0 0 .000

4 . 6 0 2

0 0 . 0 0 0

1 6 1 2 . 2 0 7

0 0 . 0 0 0

0 0 . 0 0 0

3 8 1 . 5 8 0

3RD

3 . 4 7 7

1 4 1 . 1 4 6

5 . 6 9 9

0 0 .000

2 9 1 . 4 6 2

4 1 5 2 . 6 1 8

0 0 .000

5 .699

6 66 2 . 8 2 3

1 5 5 0 3 . 1 9 0

317 2 .501

44 1 . 6 4 3

0 0 .000

214 2 . 3 3 0

3 . 4 7 7

312 2 . 4 9 4

27 1 . 4 3 1

426 2 . 6 2 9

3 . 4 7 7

4 . 6 0 2 1 2 4 2

3 . 0 9 4

4TH

2 2 1 . 3 4 2

0 0 . 0 0 0

4 . 6 0 2

0 0 . 0 0 0

2 9 0 2 . 4 6 2

2Y 1 . 4 6 2

0 0 . 0 0 0

0 0 . 0 0 0

3 2 6 2 . 5 1 3

3 3 8 2 . 5 2 9

2 3 3 2 .367

0 0 . 0 0 0

0 0 . 0 0 0

8 2 6 2 . 9 1 7

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

1 4 1 2 3 . 1 5 0

3 . 4 7 7

8 . 9 0 3 1 6 7 5

3 . 2 2 4

5TH

0 0 . 0 0 0

4 . 6 0 2

0 0 . 0 0 0

0 0 . 0 0 0

1 7 0 2 . 2 3 0

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

31 1 . 4 9 1

1 4 0 2 . 1 4 6

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

1 6 7 2 . 2 2 3

0 0 .000

3 5 1 . 5 4 4

0 0 . 0 0 0

2777 3 . 4 4 4

0 0 . 0 0 0

0 0 . 0 0 0

9 6 1 . 9 8 2

6TH

6 . 7 7 8

0 0 . 0 0 0

30 1 . 4 7 7

0 0 . 0 0 0

1 7 1 . 2 3 0

0 0 . 0 0 0

0 0 .000

0 0 .000

6 4 4 2 . 8 0 9

1 2 0 4 3 . 0 8 1

0 0 . 0 0 0

0 0 .000

40 1 . 6 0 2

3 5 1 . 5 4 4

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

5 9 5 2 . 7 7 5

0 0 . 0 0 0

0 0 . 0 0 0

1 1 5 2 . 0 6 1

2 3 9

SUM

7 9 1 . 8 9 8

234 2 . 3 6 9

1 9 9 2 . 2 9 9

5 6 1 . 7 4 8

1 1 7 9 3 . 0 7 2

1 1 0 0 3 . 0 4 1

3 2 1 . 5 0 5

5 . 6 9 9 1 8 3 5

3 . 2 6 4 4 8 2 6

3 . 6 8 4 1 8 8 0

3 . 2 7 4 1 2 8

2 . 1 0 7 2 1 6

2 . 3 3 4 2 0 2 9

3 .307 3

. 4 7 7 3 5 1

2 . 5 4 5 27

1 . 4 3 1 5 7 4 5

3 .759 6

. I 7 8 1 2

1 . 0 7 9 4 9 7 9

3 . 6 9 7

240 CHAPTER 5



TI 62 1 .792

TL 0 0 .000

TN 0 0 .000

TO 283 2 .452

TP 0 0 .000

TR 693 2 .841

TS 7 . 845

TT 0 0 .000

TU 1 9 2 2 .283

TW 28 1 . 4 4 7

TY 7 6 1 . 8 8 1

U A 0 0.000

U B 0 0 .000

'JC 0 0 .000

O D 0 0 .000

U E 0 0 .000

UF 0 0 .000

UG 0 0 .000

U I 0 0 .000

U K 0 0 .000

U L 0 0 .000

2N D

6 8 1 . 8 3 3

3 5 1 .544

0 0 .000

297 2 .473

0 0 .000

278 2 .444

0 0 .000

1 7 7 2 .248

3 3 1 2 .520

0 0 .000

3 .477

204 2 .310

233 2 .367

269 2 .430

44 1 . 6 4 3

8 3 1 . 9 1 9

40 1 . 6 0 2

7 1 1 . 8 5 1

217 2 .336

4 . 602

1 3 8 2 .140

3RD

7 7 3 2 .888

57 1 .756

36 1 .556

6 4 1 . 8 0 6

8 . 9 0 3

1 7 6 2 .246

210 2 .322

1 0 0 7 3 .003

203 2 .307

7 7 3 2 .888

0 0 .000

294 2 .468

29 1 . 4 6 2

1 1 2 2 .049

3 37 2 .528

42 1 . 6 2 3

8 . 9 0 3

127 2 .104

1 9 1 . 2 7 9

0 0 .000

2 8 1 . 4 4 7

4TH

2558 3 . 4 0 8

1 0 8 2 . 0 3 3

46 1 . 6 6 3

6 3 3 2 .801

0 0 .000

484 2 . 6 8 5

0 0 .000

244 2.387

747 2 .873

11 1 . 0 4 1

0 0 .000

57 1 .756

1 4 2 2 .152

1 0 5 2 . 0 2 1

1 5 1 . 1 7 6

7 1 1 . 8 5 1

0 0 .000

7 8 3 2 .894

214 2 .330

0 0 .000

490 2 .690

5TH

97 1 .987

378 2 .577

0 0 .000

246 2 .391

0 0 .000

390 2 . 5 9 1

0 0 .000

1 9 1 . 2 7 9

1 0 1 . 0 0 0

0 0 .000

0 0 .000

1 0 2 2 .009

0 0 .000

224 2 .350

1 3 4 2 .127

107 2 .029

0 0 .000

974 2 .989

57 1 . 7 5 6

0 0 .000

9 5 1 . 9 7 8

6TH

0 0 .000

0 0 .000

0 0 .000

1 7 1 . 2 3 0

0 0 .000

0 0 .000

1 6 7 8 3 . 2 2 5

1 6 1 .204

0 0 .000

0 0 .000

1 0 1 0 3 .004

0 0 .000

4 . 6 0 2

0 0 .000

5 .699

-77 1 . 8 8 6

0 0 .000

0 0 .000

0 0 .000

0 0 .000

1 8 8 2 .274

SUM

3558 3 .551

578 2 .762

82 1 . 9 1 4

1 5 4 0 3 .188

8 . 9 0 3 2021

3 .306 1 8 9 5

3 .278 1 4 6 3

3 .165 1 4 8 3

3 . 1 7 1 8 1 2

2 .910 1 0 8 9

3 .037 6 57

2 .818 408

2 .611 710

2 .851 5 3 5

2 .728 380

2 .580 48

1 . 6 8 1 1 9 5 5

3 .291 507

2 .705 4

. 602 9 3 9

2 .973

APPENDIX 5 . 2


BIGRAM POSITION 1ST

UM 0 0 . 0 0 0

U N 247 2 . 3 9 3

uo 0 0 . 0 0 0

UP 29 1 . 4 6 2

U R 1 2 1 . 0 7 9

US 2 2 3 2 . 3 4 8

UT 9 2 1 . 9 6 4

U Z 0 0 . 0 0 0

VA 374 2 . 5 7 3

VE 1 9 6 2 .292

V I 409 2 . 6 1 2

vo 6 0 1 . 7 7 8

vu 4 . 6 0 2

WA 498 2 . 6 9 7

WB 0 0 . 0 0 0

WD 0 0 . 0 0 0

WE 5 5 9 2 .747

WF 0 0 . 0 0 0

WH 446 2 . 6 4 9

W I 1 0 1 8 3 . 0 0 8

WK 0 0 .000

2 N D

216 2 . 3 3 4

481 2 . 6 8 2

3 . 4 7 7

337 2 . 5 2 8

1 1 8 5 3 . 0 7 4

6 3 1 2 . 8 0 0

5 0 8 2 . 7 0 6

29 1 . 4 6 2

5 . 6 9 9

2 9 8 2 .474

5 6 1 . 7 4 8

27 1 . 4 3 1

0 0 .000

4 4 1 . 6 4 3

0 0 .000

0 0 .000

3 2 1 . 5 0 5

1 0 1 . 0 0 0

0 0 . 0 0 0

4 3 1 . 6 3 3

11 1 . 0 4 1

3 RD

29 1 . 4 6 2

8 1 2 2 .910

0 0 .000

3 4 1 . 5 3 1

3 1 3 2 .496

2 9 1 2 .464

9 8 1 . 9 9 1

0 0 .000

1 3 0 2 . 1 1 4

7 9 0 2 . 8 9 8

3 5 8 2 . 5 5 4

1 4 3 2 . 1 5 5

0 0 .000

7 7 1 . 8 8 6

1 0 1 . 0 0 0

11 1 . 0 4 1

576 2 . 7 6 0

0 0 .000

29 1 . 4 6 2

0 0 . 0 0 0

0 0 . 0 0 0

4TH

2 1 2 2 . 3 2 6

1 2 0 2 . 0 7 9

1 0 1 . 0 0 0

5 . 6 9 9

444 2 . 6 4 7

1 5 6 2 . 1 9 3

2 5 8 2 . 4 1 2

0 0 . 0 0 0

2 7 8 2 .444

2 4 5 2 . 3 8 9

8 9 2 2 . 9 5 0

2 7 1 . 4 3 1

0 0 . 0 0 0

1 6 9 2 . 2 2 8

0 0 . 0 0 0

3 2 1 . 5 0 5

8 6 7 2 . 9 3 8

0 0 . 0 0 0

0 0 . 0 0 0

377 2 . 5 7 6

0 0 . 0 0 0

5TH

3 0 1 . 4 7 7

1 6 2 2 . 2 1 0

0 0 . 0 0 0

1 3 1 . 1 1 4

9 3 6 2 . 9 7 1

9 3 3 2 . 9 7 0

9 5 1 . 9 7 8

0 0 . 0 0 0

8 0 1 . 9 0 3

1 0 2 6 3 . 0 1 1

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

1 3 6 2 . 1 3 4

0 0 . 0 0 0

0 0 . 0 0 0

1 2 9 2 . 1 1 1

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

6TH

207 2 . 3 1 6

2 3 1 . 3 6 2

0 0 . 0 0 0

6 . 7 7 8

3 9 1 . 5 9 1

664 2 . 8 2 2

6 2 7 2 . 7 9 7

0 0 . 0 0 0

0 0 . 0 0 0

6 2 9 2 .799

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

0 0 .000

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

2 4 1

SUM

6 9 4 2 . 8 4 1

1 8 4 5 3 . 2 6 6

1 3 1 . 1 1 4

4 24 2 . 6 2 7

2 9 2 9 3 . 4 6 7

2898 3 . 4 6 2

1 6 7 8 3 . 2 2 5

29 1 . 4 6 2

8 6 7 2 . 9 3 8

3184 3 . 5 0 3

1 7 1 5 3 . 2 3 4

2 57 2 . 4 1 0

4 . 6 0 2

9 2 4 2 . 9 6 6

1 0 1 . 0 0 0

4 3 1 . 6 3 3

2 1 6 3 3 . 3 3 5

1 0 1 . 0 0 0

4 7 5 2 . 6 7 7

1 4 3 8 3 . 1 5 8

11 1 . 0 4 1

242 CHAPTER 5



WL 0 0 .000

WM 0 0 .000

WN 0 0 .000

WO 3 8 9 2 . 5 9 0

WP 0 0 . 0 0 0

WR 370 2 .568

ws 0 0 . 0 0 0

WY 9 . 9 5 4

X A 0 0 . 0 0 0

xc 0 0 . 0 0 0

X E 0 0 . 0 0 0

XH 0 0 . 0 0 0

X I 0 0 . 0 0 0

XP 0 0 . 0 0 0

XT 0 0 . 0 0 0

xw 0 0 . 0 0 0

YA 2 8 1 . 4 4 7

YB 0 0 .000

YC 0 0 . 0 0 0

Y E 9 . 9 5 4

YF 0 0 .000

2ND

0 0 .000

0 0 . 0 0 0

0 0 . 0 0 0

2 1 1 . 3 2 2

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

0 0 .000

4 3 5 2 . 6 3 8

4 9 1 . 6 9 0

20 1 . 3 0 1

3 2 1 . 5 0 5

40 1 . 6 0 2

298 2 . 4 7 4

8 0 1 . 9 0 3

0 0 . 0 0 0

0 0 .000

0 0 . 0 0 0

0 0 . 0 0 0

11 1 . 0 4 1

0 0 . 0 0 0

3RD

3 . 4 7 7

0 0 .000

0 0 . 0 0 0

0 0 . 0 0 0

27 1 . 4 3 1

4 . 6 0 2

4 . 6 0 2

2 3 1 . 3 6 2

8 . 9 0 3

0 0 . 0 0 0

0 0.00(1

0 0 .000

177 2 .248

0 0 .000

1 1 8 2 .072

11 1 . 0 4 1

3 2 1 . 5 0 5

81 1 . 9 0 8

11 1 . 0 4 1

4 . 6 0 2

0 0 . 0 0 0

4TH

3 1 1 . 4 9 1

3 . 4 7 7

2 1 1 . 3 2 2

44 1 . 6 4 3

0 0 . 0 0 0

0 0 . 0 0 0

0 0 .000

0 0 .000

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

0 0 .000

0 0 .000

0 0 .000

0 0 .000

0 0 . 0 0 0

0 0 .000

0 0 . 0 0 0

5 . 6 9 9

6 4 1 . 8 0 6

3 . 4 7 7

5TH

0 0 .000

0 0 . 0 0 0

4 . 6 0 2

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

3 1 1 . 4 9 1

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

0 0 .000

0 0 . 0 0 0

0 0 . 0 0 0

9 9 1 . 9 9 6

0 0 . 0 0 0

6TH

0 0 . 0 0 0

0 0 . 0 0 0

5 6 1 . 7 4 8

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

1 9 8 2 . 2 9 7

0 0 .000

0 0 . 0 0 0

0 0 . 0 0 0

0 0 .000

0 0 . 0 0 0

0 0 .000

0 0 . 0 0 0

3 8 1 . 5 8 0

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

6 . 7 7 8

0 0 . 0 0 0

SUM

3 4 1 . 5 3 1

3 . 4 7 7

81 1 . 9 0 8

4 54 2 . 6 5 7

27 1 . 4 3 1

374 2 . 5 7 3

2 0 2 2 . 3 0 5

3 2 1 . 5 0 5

4 4 3 2 . 6 4 6

4 9 1 . 6 9 0

5 1 1 . 7 0 8

32 1 . 5 0 5

2 1 7 2 . 3 3 6

298 2 . 4 7 4

2 36 2 . 3 7 3

11 1 . 0 4 1

6 0 1 . 7 7 8

8 1 1 . 9 0 8

1 6 1 . 2 0 4

1 9 3 2 . 2 8 6

3 . 4 7 7

APPENDIX 5 . 2



YG 0 0 . 0 0 0

Y H 0 0 .000

Y I 1 2 1 . 0 7 9

Y L 0 0 . 0 0 0

YM 0 0 . 0 0 0

Y N 0 0 . 0 0 0

Y O 44 1 . 6 4 3

YP 0 0 . 0 0 0

YR 0 0 . 0 0 0

YS 0 0 . 0 0 0

YT 0 0 . 0 0 0

YW 0 0 . 0 0 0

Y Z 0 0 . 0 0 0

Z A 0 0 . 0 0 0

Z E 7 .84 5

Z I 0 0 . 0 0 0

Z L 0 0 . 0 0 0

z o 0 0 . 0 0 0

z u 0 0 . 0 0 0

Z Y 0 0 . 0 0 0

z z 0 0 . 0 0 0

2ND

3 . 4 1 7

0 0 .000

0 0 .000

0 0 . 0 0 0

4 1 1 . 6 1 3

3 3 1 . 5 1 9

9 . 9 5 4

7 2 1 . 8 5 7

1 8 1 . 2 5 5

1 7 9 2 . 2 5 3

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

0 0 .000

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

0 0 .000

0 0 . Q 0 0

0 0 . 0 0 0

3RD

0 0 . 0 0 0

8 . 9 0 3

0 0 . 0 0 0

1 2 1 . 0 7 9

8 1 1 . 9 0 8

1 3 1 . 1 1 4

0 0 .000

3 .477

54 1 . 7 3 2

4 5 1 . 6 5 3

3 1 1 . 4 9 1

1 7 1 . 2 3 0

0 0 .000

32 1 . 5 0 5

1 0 1 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

0 0 .000

0 0 . 0 0 0

11 1 . 0 4 1

29 1 . 4 6 2

4TH

0 0 . 0 0 0

0 0 . 0 0 0

1 9 4 2 .288

0 0 . 0 0 0

11 1 . 0 4 1

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

27 1 . 4 3 1

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

3 9 1 . 5 9 1

2 3 1 . 3 6 2

9 - 9 5 4

6 . I 7 8

0 0 .000

0 0 . 0 0 0

5TH

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

0 0 .000

7 . 8 4 5

0 0 . 0 0 0

0 0 . 0 0 0

1 0 1 . 0 0 0

0 0 .000

3 3 1 . 5 1 9

0 0 .000

0 0 . 0 0 0

27 1 . 4 3 1

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

6TH

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

3 . 4 7 7

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

57 1 . 7 5 6

0 0 . 0 0 0

0 0 . 0 0 0

0 0 .000

3 . 4 7 7

1 0 0 2 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

0 0 . 0 0 0

2 4 3

SUM

3 . 4 7 7

8 . 9 0 3

2 0 6 2 . 3 1 4

1 2 1 . 0 7 9

1 3 6 2 . 1 3 4

46 1 . 6 6 3

5 3 1 . 7 2 4

7 5 1 . 8 7 5

7 2 1 . 8 5 7

2 8 8 2 . 4 5 9

5 8 1 . 7 6 3

1 7 1 . 2 3 0

1 0 1 . 0 0 0

3 5 1 . 5 4 4

1 5 0 2 . 1 7 6

3 9 1 . 5 9 1

2 3 1 . 3 6 2

36 1 . 5 5 6

6 . I 1 8

11 1 . 0 4 1

29 1 . 4 6 2

6 Summary and Conclusion

The g o a l o f t h i s r e s e a r c h p r o j e c t was t o e v a l u a t e how t h e r e a d e r ' s h i g h e r - o r d e r knowledge a b o u t o r t h o g r a p h i c s t r u c t u r e i n t e r a c t s w i t h f e a t u r a l i n f o r m a t i o n d u r i n g t h e p r o c e s s i n g o f l e t t e r s and w o r d s . The r e s e a r c h was c a r r i e d o u t u t i l i z i n g a g e n e r a l i n f o r m a t i o n p r o c e s s i n g mode l , which p r o v i d e d a f o r m a l f ramework f rom which h y p o t h e s e s c o u l d b e d e r i v e d and t e s t e d . The model a l o n g w i t h s u p p o r t i n g e v i d e n c e was d e s c r i b e d i n C h a p t e r 1. S i n c e t h e s t u d y o f v i s u a l p r o c e s s i n g i n r e a d i n g r e q u i r e s a n e x a m i n a t i o n o f t h e v i s u a l f e a t u r e s t h a t a r e f u n c t i o n a l d u r i n g r e a d i n g , t h e d i s c u s s i o n i n C h a p t e r 2 d e s c r i b e d t h o s e f e a t u r e s u t i l i z e d i n t h e r e c o g n i t i o n o f l o w e r c a s e l e t t e r s . U n d e r s t a n d i n g f e a t u r e d e t e c t i o n p r o v e d u s e f u l i n a c c o u n t i n g f o r some o f t h e f i n d i n g s i n t h e p e r c e p t u a l r e c o g n i t i o n t a s k s d e s c r i b e d i n C h a p t e r 4 . The s i g n i f i c a n t f i n d i n g was t h a t t h e s e a r c h f o r a t a r g e t l e t t e r was c r i t i c a l l y d e p e n d e n t o n t h e f e a t u r a l s i m i l a r i t y b e t w e e n t h e t a r g e t l e t t e r and t h e l e t t e r s i n t h e t e s t s t r i n g .

The f u n d a m e n t a l p r o p e r t i e s o f t h e o r t h o g r a p h i c s t r u c t u r e o f E n g l i s h were d e s c r i b e d i n C h a p t e r 3. We d i s t i n g u i s h e d two b r o a d c a t e g o r i e s o f d e s c r i p t i o n s . The f i r s t was d e r i v e d f rom s t a t i s t i c a l - r e d u n d a n c y m e a s u r e s b a s e d o n t h e f r e q u e n c y w i t h wh ich l e t t e r s , l e t t e r s e q u e n c e s , and words o c c u r i n n a t u r a l t e x t s . The s e c o n d c a t e g o r y , r u l e - g o v e r n e d r e g u l a r i t y , was b a s e d o n p h o n o l o g i c a l c o n s t r a i n t s o f E n g l i s h and s c r i b a l c o n v e n t i o n s g o v e r n i n g t h e s p e l l i n g o f E n g l i s h . A l s o i n c l u d e d i n C h a p t e r 3 was a b r i e f r e v i e w o f p r e v i o u s s t u d i e s o f o r t h o g r a p h y .

I n C h a p t e r 4 , w e examined t h e p s y c h o l o g i c a l r e a l i t y o f v a r i o u s d e s c r i p t i o n s o f o r t h o g r a p h i c s t r u c t u r e i n p e r c e p t u a l r e c o g n i t i o n t a s k s and o v e r t j u d g m e n t t a s k s . The r e c o g n i t i o n

2 4 6 CHAPTER 6

t a s k s a s s e s s e d t h e d e g r e e t o which knowledge o f o r t h o g r a p h i c s t r u c t u r e is u t i l i z e d i n word p e r c e p t i o n , and t h e o v e r t j udgmen t t a s k s a s s e s s e d t h e d e g r e e - t o wh ich t h i s knowledge is c o n s c i o u s l y a v a i l a b l e .

G i v e n o u r p r e v i o u s r e s u l t s (Massa ro e t a l . , 1 9 7 9 ) , we had r e a s o n t o s u s p e c t d i f f e r e n c e s be tween r e a c t i o n time t a s k s and a c c u r a c y t a s k s i n terms o f t h e i r s e n s i t i v i t i e s t o t h e u t i l i z a t i o n o f o r t h o g r a p h i c s t r u c t u r e . We b e g a n w i t h a d i r e c t c o m p a r i s o n be tween t h e s e two t a s k s , w h i l e s i m u l t a n e o u s l y c o n t r a s t i n g a r u l e - g o v e r n e d m e a s u r e and a s t a t i s t i c a l - r e d u n d a n - c y m e a s u r e o f o r t h o g r a p h i c s t r u c t u r e . Rep1 i c a t i n g o u r p r e v i o u s work, w e found h i g h l y s i g n i f i c a n t e f f e c t s o f o r t h o g r a p h i c s t r u c t u r e i n t h e a c c u r a c y t a s k and r e l a t i v e l y s m a l l , a n d somet imes n o n s i g n i f i c a n t , e f f e c t s i n t h e r e a c t i o n time t a s k . The n e x t s i x e x p e r i m e n t s a s s e s s e d wha t a s p e c t s o f t h e two t a s k s a c c o u n t e d f o r t h e d i f f e r e n c e s t h a t were o b s e r v e d . We e v a l u a t e d t h e i n f l u e n c e s o f p r e s e n t i n g t h e t a r g e t l e t t e r b e f o r e o r a f t e r t h e t e s t d i s p l a y , t h e c o n t r i b u t i o n o f a f e a t u r e d e t e c t i o n s t r a t e g y , t h e r o l e o f l i m i t e d s t i m u l u s i n f o r m a t i o n , and t h e s e n s i t i v i t y o f s p e e d e d r e a c t i o n - t i m e e x p e r i m e n t s . The r e a s o n t h a t t h e m a g n i t u d e o f t h e e f f e c t a p p e a r s s m a l l e r f o r a h i g h a c c u r a c y r e a c t i o n - t i m e m e a s u r e is t h a t t h e d i f f e r e n c e s i n v i s u a l p r o c e s s i n g time a r e s m a l l r e l a t i v e t o t h e o v e r a l l r e a c t i o n time t o c o m p l e t e t h e t a s k . I n c o n t r a s t , t h e s t i m u l u s p a r a m e t e r s a r e m o d i f i e d i n t h e a c c u r a c y t a s k t o k e e p a v e r a g e p e r f o r m a n c e a t 7 5 % c o r r e c t ; a n y d i f f e r e n c e s i n a c c u r a c y a r e t h e n i n f l u e n c e d a l m o s t c o m p l e t e l y by v i s u a l p r o c e s s i n g . S u p p o r t i n g t h i s i n t e r p r e t a t i o n , t h e p o s t hoc e v a l u a t i o n o f v a r i o u s m e a s u r e s o f o r t h o g r a p h i c s t r u c t u r e r e v e a l e d r e a s o n a b l y good c o r r e l a t i o n s w i t h r e a c t i o n t ime b u t much h i g h e r c o r r e l a t i o n s w i t h a c c u r a c y .

To p r o v i d e a q u a n t i t a t i v e d e s c r i p t i o n o f t a s k a c c u r a c y , we f o r m a l i z e d t h e i n f o r m a t i o n p r o c e s s i n g model d e v e l o p e d i n C h a p t e r 1. T h i s model a l l o w s a f o r m a l d e s c r i p t i o n o f t h e f a c i l i t a t i v e e f f e c t o f o r t h o g r a p h i c s t r u c t u r e o n b o t h r e a c t i o n time and t a s k a c c u r a c y . The b a s i c a s s u m p t i o n o f t h e model i s t h a t knowledge o f o r t h o g r a p h i c s t r u c t u r e c o n t r i b u t e s a n i n d e p e n d e n t s o u r c e o f i n f o r m a t i o n a b o u t t h e l e t t e r s t r i n g . C o n s e q u e n t l y , f e w e r v i s u a l f e a t u r e s a r e n e c e s s a r y t o r e s o l v e w e l l - s t r u c t u r e d s t r i n g s t h a n t o r e s o l v e p o o r l y - s t r u c t u r e d s t r i n g s . The model was a p p l i e d t o t h e t a r g e t s e a r c h t a s k by f o r m a l i z i n g a d e c i s i o n a l g o r i t h m assumed t o b e used by t h e s u b j e c t when f a c e d w i t h p a r t i a l i n f o r m a t i o n . The model p r o v i d e d a good q u a n t i t a t i v e d e s c r i p t i o n o f t h e r e s u l t s from t h e a c c u r a c y t a s k . The p a r a m e t e r s o f t h e model were

SUMMARY AND CONCLUSION 247

p s y c h o l o g i c a l l y m e a n i n g f u l and t h e p a r a m e t e r v a l u e s c o r r e s p o n d i n g t o t h e number o f l e t t e r s s e e n i n t h e test s t r i n g s p r o v i d e d a q u a n t i t a t i v e measure o f t h e c o n t r i b u t i o n o f o r t h o g r a p h i c s t r u c t u r e . A c c o r d i n g t o t h e m o d e l , o u r r e a d e r s were a b l e t o r e c o g n i z e two a d d i t i o n a l l e t t e r s i n we 1 1-st r uc t u r ed s t r i n g s compared t o poo r l y - s t r uc t u r e d s t r i n g s . T h i s i s a s u b s t a n t i a l e f f e c t c o n s i d e r i n g t h a t two l e t t e r s r e p r e s e n t o n e - t h i r d o f t h e s i x - l e t t e r t e s t s t r i n g .

We a l s o c a r r i e d o u t a s e r i e s o f o v e r t j u d g m e n t e x p e r i m e n t s t o assess which d e s c r i p t i o n s o f o r t h o g r a p h i c s t r u c t u r e a r e c o n s c i o u s l y a v a i l a b l e . We a s k e d w h e t h e r s u b j e c t s c o u l d r e l i a b l y a s s i g n r a t i n g s o f how much a l e t t e r s t r i n g r e s e m b l e s w r i t t e n E n g l i s h o n t h e b a s i s o f t h e t y p i c a l i t y o f t h e l e t t e r s e q u e n c i n g i n t h e t e s t s t r i n g s . I n a d d i t i o n , o t h e r s u b j e c t s were a s k e d t o d i s c r i m i n a t e t h e i tems o n t h e b a s i s o f r u l e - g o v e r n e d r e g u l a r i t y o r o n t h e b a s i s o f s t a t i s t i c a l r e d u n d a n c y . S u b j e c t s ' j u d g m e n t s were more a c c u r a t e l y d e s c r i b e d b y r u l e - g o v e r n e d r e g u l a r i t y t h a n by s t a t i s t i c a l r edun- d a n c y . F i n a l l y , t h e r a t i n g s o f t h e i n d i v i d u a l items c o r r e l a t e d q u i t e s t r o n g l y w i t h t h e i r a c c u r a c i e s and r e a c t i o n t imes i n t h e t a r g e t s e a r c h t a s k .

The f a c t o r i a l d e s i g n o f our e x p e r i m e n t s c o n t r a s t e d j u s t o n e m e a s u r e o f r u l e - g o v e r n e d r e g u l a r i t y w i t h o n e m e a s u r e o f s t a t i s t i c a l r e d u n d a n c y . T h e r e f o r e , w e c o n d u c t e d a l a r g e number o f p o s t h o c c o r r e l a t i o n a l a n a l y s e s t o e v a l u a t e a w i d e r a n g e o f m e a s u r e s o f o r t h o g r a p h i c s t r u c t u r e . The d e p e n d e n t m e a s u r e s were t h e r e a c t i o n t imes , a c c u r a c y , and r a t i n g r e s p o n s e s t o e a c h o f 200 t e s t i tems . p o s i t i o n - s e n s i t i v e l o g b ig ram f r e q u e n c y p r o v i d e d t h e b e s t d e s c r i p t i o n o f p e r f o r m a n c e on t h e i n d i v i d u a l t e s t i tems . However, o u r r u l e - b a s e d r e g u l a r i t y m e a s u r e a l s o p r o v i d e d a v e r y good d e s c r i p t i o n . I n f a c t , o u r r e g u l a r i t y m e a s u r e c o r r e l a t e d v e r y h i g h l y w i t h t h e b e s t f r e q u e n c y - b a s e d m e a s u r e . T h e r e f o r e , we w e r e n o t s u c c e s s f u l i n c h o o s i n g b e t w e e n r u l e - g o v e r n e d r e g u l a r i t y and s t a t i s t i c a l r e d u n d a n c y i n t h e s e e x p e r i m e n t s .

We were a l s o a b l e t o e v a l u a t e t h e m o s t a p p r o p r i a t e m e a s u r e s f o r a s t a t i s t i c a l - r e d u n d a n c y d e s c r i p t i o n . We o b t a i n e d i n f o r m a t i o n a b o u t t h e u t i l i t y o f t y p e v e r s u s t o k e n c o u n t s , t h e a p p r o p r i a t e s c a l e f o r d e s c r i b i n g f r e q u e n c y o f o c c u r r e n c e , p o s i t i o n - s e n s i t i v e v e r s u s p o s i t i o n - i n s e n s i t i v e c o u n t s o f l e t t e r o c c u r r e n c e s , t h e r o l e o f word f r e q u e n c y , and t h e r e l a t i v e c o n t r i b u t i o n s o f v a r i o u s s e r i a l p o s i t i o n s i n d e t e r m i n i n g t h e o r t h o g r a p h i c s t r u c t u r e o f a n item.

What c o n c l u s i o n s c a n b e r e a c h e d and wha t a r e t h e i m p l i c a t i o n s f o r f u t u r e r e s e a r c h and c l a s s r o o m

2 4 8 CHAPTER 6

p r a c t i c e ? A l t h o u g h we were n o t s u c c e s s f u l i n c h o o s i n g be tween r u l e - g o v e r n e d r e g u l a r i t y and s t a t i s t i c a l r e d u n d a n c y i n t h e s e e x p e r i m e n t s , a d d i t i o n a l e x p e r i m e n t s m i g h t b e s u c c e s s f u l . G i v e n t h e b e s t s t a t i s t i c a l - r e d u n d a n c y m e a s u r e , i t s h o u l d b e p o s s i b l e t o d e v e l o p a new se t o f t e s t i tems t o c o n t r a s t t h i s m e a s u r e w i t h a r u l e - g o v e r n e d r e g u l a r i t y m e a s u r e . We p l a n t o f o l l o w t h e l o g i c o f t h e p r e s e n t s t u d i e s by c o n t r a s t i n g l o g b ig ram f r e q u e n c y and r e g u l a r i t y m e a s u r e s i n t a r g e t s e a r c h and o v e r t j udgmen t t a s k s . A l t h o u g h t h e s e two m e a s u r e s a r e h i g h l y c o r r e l a t e d , i t s h o u l d b e p o s s i b l e t o d i s t i n g u i s h be tween them. G i v e n t h e r e s u l t s , i t w i l l s t i l l b e n e c e s s a r y t o c a r r y o u t p o s t hoc c o r r e l a t i o n s t o d e t e r m i n e i f some o t h e r m e a s u r e m i g h t p r o v i d e e v e n a b e t t e r d e s c r i p t i o n . T h i s r e s e a r c h h a s t h e p r o m i s e o f l e a d i n g t o t h e d e s c r i p t i o n t h a t b e s t r e f l e c t s t h e knowledge o f o r t h o g r a p h i c s t r u c t u r e used i n t h e c o u r s e o f no rma l r e a d i n g .

A r r i v i n g a t a good d e s c r i p t i o n o f o r t h o g r a p h i c s t r u c t u r e s h o u l d b e b e n e f i c i a l i n t h e d e v e l o p m e n t o f r e a d i n g i n s t r u c t i o n . G i v e n t h a t t h e u t i l i z a t i o n o f o r t h o g r a p h i c s t r u c t u r e i s a n i m p o r t a n t component i n l e t t e r and word r e c o g n i t i o n , i n s t r u c t i o n a l m a t e r i a l s s h o u l d b e d e s i g n e d t o f a c i l i t a t e c h i l d r e n ' s u n d e r s t a n d i n g o f t h i s s t r u c t u r e . C u r r e n t p h o n i c s p rograms a d d r e s s o n l y t h e c o r r e s p o n d e n c e s be tween s p e l l i n g and s o u n d , n o t t h e c o n s t r a i n t s i n E n g l i s h o r t h o g r a p h y . Y a s s a r o and T a y l o r ( 1 9 7 9 ) s k e t c h a s e r i e s o f c l a s s r o o m games t h a t m i g h t b e employed t o t e a c h c h i l d r e n common l e t t e r p a t t e r n s and t h e l o c a t i o n s i n words t h e s e l e t t e r p a t t e r n s a r e m o s t l i k e l y t o b e found . D e l i n e a t i n g t h e b e s t d e s c r i p t i o n o f o r t h o g r a p h i c s t r u c t u r e m i g h t f a c i l i t a t e t h e t e a c h i n g and l e a r n i n g o f t h i s s t r u c t u r e .

A l l p o r t , A . Word r e c o g n i t i o n i n r e a d i n g ( T u t o r i a l p a p e r ) . I n P. A. K o l e r s , M . W r o l s t a d , & H . Bouma ( E d s . ) , P r o c e s s i n g -~ o f v i s i b l e l a n g u a g e r. N e w York: Plenum, 1979.

A n d e r s o n , I . H . , & D e a r b o r n , W . F. The p s y c h o l o g y of t e a c h i n g r e a d i n g . N e w York: Ronald P r e s s , 1952.

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Oden, G . C . , & Massa ro , D. W. I n t e g r a t i o n o f f e a t u r a l i n f o r m a t i o n i n s p e e c h p e r c e p t i o n . P s y c h o l o g i c a l Rev iew, 1 9 7 8 , c ( 3 ) , 172-191.

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Glossary

a c c u r a c y t a s k : a t a s k i n wh ich a c c u r a c y i s t h e p r i m a r y d e p e n d e n t m e a s u r e ; i n t h e t a r g e t s e a r c h t a s k , a v e r a g e p e r f o r m a n c e i s m a i n t a i n e d a t 7 5 % c o r r e c t by a d j u s t i n g t h e d u r a t i o n o f t h e t e s t s t r i n g a n d / o r t h e p r o c e s s i n g t ime a v a i l a b l e .

anagram: a p e r m u t a t i o n o f t h e l e t t e r s c o m p r i s i n g a word.

b ig ram: a t w o - l e t t e r c l u s t e r .

c a t c h t r i a l : a t r i a l d u r i n g which t h e t a r g e t l e t t e r d o e s n o t -- a p p e a r i n t h e t e s t s t r i n g .

f e a t u r e d e t e c t i o n : a p r o c e s s wh ich a n s w e r s t h e q u e s t i o n o f w h e t h e r o r n o t a p a r t i c u l a r f e a t u r e is p r e s e n t a n d / o r p r o v i d e s i n f o r m a t i o n a b o u t t h e d e g r e e t o wh ich t h e f e a t u r e i s p r e s e n t .

f o u r i e r a n a l y s i s : t h e d e s c r i p t i o n o f a v i s u a l d i s p l a y i n t e rms o f i n t e n s i t y and f r e q u e n c y o f component s i n e waves.

f u l l r e p o r t : g i v e n a d i s p l a y o f i t ems , s u b j e c t s a r e a s k e d t o r e p o r t a l l o f t h e i tems i n t h e d i s p l a y .

g e n e r a t e d a b s t r a c t memory: m o d a l i t y - f r e e ( a b s t r a c t ) s t o r a g e , a n a l o g o u s t o s h o r t - t e r m memory.

g r a p h e m i c c o n s t r a i n t s : s ee s c r i b a l c o n s t r a i n t s .

2 6 3

264 G L O S S A R Y

high s p a t i a l f r e q u e n c i e s : t h e h i g h f r e q u e n c i e s o f a f o u r i e r a n a l y s e s o f a v i s u a l d i s p l a y .

homophones: d i f f e r e n t words t h a t a r e p ronounced i d e n t i c a l l y , s u c h a s r i g h t / w r i t e .

i n f o r m a t i o n : s o u r c e o f knowledge a v a i l a b l e t o t h e r e a d e r ; f o r e x a m p l e , t h e f e a t u r a l i n f o r m a t i o n i n p r e p e r c e p t u a l s t o r a g e o r t h e r e a d e r ' s memory o f l e t t e r p a t t e r n s i n t h e l a n g u a g e .

l e x i c o n : s t o r a g e o f p e r c e p t u a l and c o n c e p t u a l c o d e s o f w o r d s i n l o n g - t e r m memory; e a c h word h a s p e r c e p t u a l c o d e s s u c h a s t h e sound and v i s u a l p a t t e r n o f t h e word and c o n c e p t u a l c o d e s s u c h a s i t s mean ing .

l ong- t e rm memory: r e l a t i v e l y pe rmanen t s t o r e o f knowledge i n t e r m o f c o d e s , r u l e s , and p r o c e d u r e s ( s c h e m a t a ) .

- l o w s p a t i a l f r e q u e n c i e s : t h e low f r e q u e n c i e s o f a f o u r i e r a n a l y s i s o f a v i s u a l d i s p l a y .

morpheme i d e n t i t y : r e t e n t i o n o f s p e l l i n g s i m i l a r i t y o f s e m a n t i c a l l y - r e l a t e d w o r d s , s u c h a s c o n e / c o n i c .

nonword: a l e t t e r s t r i n g t h a t d o e s n o t s p e l l a word; s o m e t i m e s used t o mean t h a t t h e l e t t e r s t r i n g a l s o d o e s not confo rm t o s t a n d a r d E n g l i s h s p e l l i n g , i . e . , i t v i o l a t e s E n g l i s h o r t h o g r a p h y .

o r t h o g r a p h i c r e g u l a r i t y : d e s c r i p t i o n o f o r t h o g r a p h i c s t r u c t u r e b a s e d upon r u l e s and g e n e r a l i z a t i o n s a b o u t t h e o b s e r v e d p a t t e r n s o f E n g l i s h o r t h o g r a p h y ; a l s o r e f e r r e d t o a s r u l e - b a s e d d e s c r i p t i o n .

o r t h o g r a p h i c s t r u c t u r e : t h e s p e l l i n g c o n s t r a i n t s i n a w r i t t e n l a n g u a g e ; i n E n g l i s h , f o r example , g i v e n i n a n i n i t i a l p o s i t i o n , r is more l i k e l y t o f o l l o w t h a n 2.

o v e r t j u d g m e n t s : j u d g m e n t s a b o u t t h e s p e l l i n g o f l e t t e r s t r i n g s ; s t u d i e d t o a s s e s s what knowledge o f o r t h o g r a p h y is c o n s c i o u s l y a v a i l a b l e and c a p a b l e o f r e p o r t .

p a r a l l e l p r o c e s s i n g : when i n f o r m a t i o n a b o u t two o r more i tems is p r o c e s s e d s i m u l t a n e o u s l y .

GLOSSARY 2 6 5

perceptual recognition: see primary recognition.

phonological constraints: the constraints on English orthography that derive from the allowable sequences of sounds in English words.

positional frequency: see position-sensitive measure.

position-dependent measure: see position-sensitive measure.

position-independent measure: see position-insensitive measure.

position-insensitive measure: a statistical-redundancy description of orthographic structure which counts letter sequences on the bases of occurrence in words of specific lengths without regard to position of occurrence; also referred to as position-independent measure.

position-sensitive measure: a statistical-redundancy description of orthographic structure which counts letter sequences on the basis of occurrence in specific positions in words of specific lengths; also referred to as position-dependent measure or positional-frequency.

postcue: when a target letter follows a test string.

precue: when a target letter precedes a test string.

preperceptual visual storage: holds features passed on by feature detection for roughly one quarter of a second.

primary recognition: joint evaluation and integration of the features in preperceptual storage and knowledge of orthographic structure in long-term memory; the outcome is a synthesized percept; also referred to as perceptual recog n i t ion.

probabilistic description: see statistical redundancy.

pseudoword: a nonword that conforms to English spelling.

reaction time (RT) task: task in which reaction time is the primary dependent measure; in the high-accuracy target search task, for example, accuracy is kept near perfect by

266 GLOSSARY

k e e p i n g t h e t e s t s t r i n g p r e s e n t d u r i n g t h e r e s p o n s e i n t e r v a l .

r e g u l a r i t y : see o r t h o g r a p h i c r e g u l a r i t y . r u l e -based d e s c r i p t i o n : see o r t h o g r a p h i c r e g u l a r i t y . s c r i b a l c o n s t r a i n t s : t h e c o n s t r a i n t s i n t h e s e l e c t i o n o f

l e t t e r s f o r e i t h e r r e p r e s e n t i n g s o u n d s o r m a r k i n g g r a p h e m i c , g r a p h o t a c t i c , o r m o r p h o l o g i c a l f u n c t i o n s ; a l s o r e f e r r e d t o a s g r a p h e m i c c o n s t r a i n t s .

s e c o n d a r y r e c o g n i t i o n : t r a n s f o r m s v i s u a l p e r c e p t h e l d i n s y n t h e s i z e d memory i n t o meaning h e l d i n g e n e r a t e d a b s t r a c t memory.

s i n g l e - l e t t e r p o s i t i o n a l f r e q u e n c y : t h e f r e q u e n c y w i t h wh ich a l e t t e r o c c u r s i n a s p e c i f i c p o s i t i o n i n words o f a s p e c i f i c l e n g t h i n a s a m p l e o f t e x t .

s p e e d e d fl task: s u b j e c t s a r e i n s t r u c t e d t o r e s p o n d more q u i c k l y t h a n t h e time needed f o r h i g h a c c u r a c y ; i n t h e t a r g e t s e a r c h t a s k , s u b j e c t s l e a r n t o r e s p o n d i n s y n c h r o n y w i t h a n e x t e r n a l s i g n a l whose r e l a t i v e o n s e t i s a d j u s t e d t o k e e p p e r f o r m a n c e a t 7 5 % c o r r e c t ; b o t h a c c u r a c y and RT a r e e v a l u a t e d a s d e p e n d e n t m e a s u r e s .

s t a t i s t i c a l r edundancy : c a t e g o r y o f d e s c r i p t i o n s o f o r t h o g r a p h i c s t r u c t u r e d e r i v e d from c o u n t s o f l e t t e r s o r l e t t e r s e q u e n c e s o c c u r r i n g i n t h e w r i t t e n l a n g u a g e ; a l s o c a l l e d p r o b a b i l i s t i c d e s c r i p t i o n .

~ _ _ _ summed c o u n t s : t h e sum o f i n d i v i d u a l f r e q u e n c i e s o f t h e l e t t e r s o r l e t t e r c l u s t e r s i n a l e t t e r s t r i n g .

s y n t h e s i z e d v i s u a l memory: h o l d s p e r c e p t u a l o u t c o m e s o f p r i m a r y r e c o g n i t i o n p r o c e s s .

t a r g e t l e t t e r : i n t h e t a r g e t s e a r c h t a s k , t h e l e t t e r whose p r e s e n c e o r a b s e n c e i n t h e t e s t s t r i n g o f l e t t e r s m u s t b e r e p o r t e d .

t a r g e t s e a r c h t a s k : t h e s u b j e c t i s g i v e n a t a r g e t l e t t e r and t h e t a s k i s t o i n d i c a t e w h e t h e r o r n o t t h e t a r g e t l e t t e r

- ~ -

is c o n t a i n e d i n a t e s t s t r i n g o f l e t t e r s .

GLOSSARY 267

- t e s t s t r i n g : i n t h e t a r g e t s e a r c h t a s k , t h e l e t t e r s t h a t m u s t be e v a l u a t e d i n te rms of p r e s e n c e o r a b s e n c e of t h e t a r g e t l e t t e r .

t o k e n c o u n t : a c o u n t based on t h e number of t o t a l o c c u r r e n c e s of an i tem; f o r example, t h e t o t a l number o f o c c u r r e n c e s of a l l words c o n t a i n i n g a p a r t i c u l a r l e t t e r .

--

t r i g r a m : a t h r e e - l e t t e r c l u s t e r .

*e count : a c o u n t based on t h e number o f un ique o c c u r r e n c e s o f an i tem; f o r example, t h e number of un ique words c o n t a i n i n g a p a r t i c u l a r l e t t e r .

Author Index A

Adams, N., 5 8 , 67 A l l p o r t , A., viii A n d e r s o n , I . H., 1 1 - 1 2 A n i s f e l d , M . A . , 25 A t k i n s o n , R. C . , 56

B

B a d d e l e y , A . D . , 7 , 64 B a r b u t o , P . F . , 27 B a r o n , J , , viii, 6 2 B e a l , A. L . , 2 4 B j o r k , E . L . , 62

Bouwhuis , D . , G . 26 B r e i t m e y e r , B . G., 1 9 B r o a d b e n t , D. E . , 1 9 , 1 4 1 , B r o w n e l l , H . , 5 8 , 67 B r u n e r , J. S., 6 , 2 4 B y r n e s , J . , 2 4

Bouma, H., 1 2 , 15-16 , 43-45, 52-53

C

C a r r , T. H . , ix

C h a n d l e r , J . P . , 59 Chomsky, N . , 35 C l a r k , H . H . , 51

C a t t e l l , J . M., 1 1 - 1 2

269

270 AUTHOR I N D E X

Conger , B. , 132 C r e e l m a n , C . D . , 93

D

D e a r b o r n , W. F. , 11-12

E

E g e t h , H . E . , 25 Es t e s , W. R . , v i i i , 5 , 6 2

F

F a n t , C. G . M . , 1 4 F r a n c i s , W. N., 26-27, 126-127, 149

G

Ganz , L . , 1 9 G e o f f r i o n , L. D . , 5 G i b s o n , E . J . , v i i i , 1, 15 , 25 , 29-38, 32 G i l m o r e , G . C . , 25 Green, D. M . , 1 7

H

H a l l e , M . , 1 4 Hammond, M., 25 , 29-30 H a v i l a n d , S . E . , 58 , 67 H e n d e r s o n , L . , v i i i Huey, E . B . , 1, 1 3 Hung, D. L . , 29

J

J a k o b s o n , ' R. , 1 4 J o h n s o n , N . F. , v i i i J o h n s t o n , J. C . , 26 , 1 0 1 , 132 J o n e s , R. D . , 7 4 , 77-18

J u o l a , J. F. , 56, 68 J u e l , C. L.r 27

AUTHOR INDEX

K

2 7 1

Kallrnan, H. J . , 5 8 K a u s l e r , D. H., 3 3

King, J. F . , 2 7 K l i t z k e , D . , 1 0 5 Kleiman, G. M . , 2 9 K o l e r s , P . A., 1 0 8 Krueger , L. E . , v i i i , 7, 4 7 Kucera, H., 2 6 - 2 7 , 1 2 6 - 1 2 7 , 1 4 9 Kurath , H., 3 5

L

Landauer , T. K . , 2 7 - 2 8 L e f t o n , L. A., 24

Levin , H., viii, 1 Levy, B. A . , 2 9

Lewis, S. S., 2 9 - 3 0 Lipscomb, c . , 7 4 , 7 7 - 7 8 Lorge, I . , 2 5

M

Macey, W. H., 2 7 Mason, M . , 2 6 , 3 7 - 3 8 , 1 3 2 Massaro, D. W.,ix, 2, 5-8, 1 7 , 19, 21, 2 6 , 2 9 ,

3 8 - 4 7 , 4 3 , 56 -58 , 6 2 , 7 4 , 7 7 - 7 8 , 9 6 , 1 0 5 ,

2 4 6 , 2 4 8 Mayzner, M . S . , 26, 4 8 , 9 1 McClel land, J . L . , 2 6 , 1 0 1 , 1 3 2

Meyer, D. E . , 7 4 , M i l l e r , G. A., 6 , 2 4 M i l l e r , T. J . , 6 8

Newhort, D, J . , 24

N

N e i s s e r , U . , 1 4 , 4 3

0

Oden, G . C . , 2 1 , O l i v i e r , D. G . , 1 2 7 - 1 2 8 , 1 3 1 O l s e n , G. A . , 3 3

272 AUTHOR INDEX

Osser, H . , 1 5 , 2 5 , 29-30

P

P i c k , A . , 25 , 29-30 P o d g o r n y , P., 1 3 1 P o l l a t s e k , A . , ix P o s t m a n , L . , 6 , 24 , 27-28, 131-132 P y l e s , T. , 32

R

R e d e r , L. M . , 5 8 , 67 Reed , A. V., 7 5 , 1 0 5 R e i c h e r , G. M., 6 , 6 2 R u b e n s t e i n , H . , 29-30 R u b e n s t e i n , M . A . , 29-30 Ruddy, M . G., 74

S

S a v i n , H. B . , 27-28 S c h i f f , W., 15 S c h m u l l e r , J., 7 , 1 7 , 1 9 , 43 S c h o l z , R. , 7 4 , 77-78 S c h u l z , R. W., 25-26 S c h v a n d e v e l d t , R. W . , 74 S e l f r i d g e , 0. G., 1 4 Shannon , C. E., 6 , 24 S h a p i r o , R . G., 7, 47 S h e b i l s k e , W. , 3 S h e p a r d , R. N., 1 3 1 S h u r c l i f f , A . , 25-26, 29-30, 132 S idman , M., 47 S k a a r , E., 6 2 S m i t h , E. E., 4 , 29-30, 5 8 , 6 7 , 132 S m i t h , J., 15 Solomon, R. L . , 27-28, 1 3 1 S o l s o , R. L., 27 S p e n c e r , H . , 11-13 S p o e h r , R. T., 132 S p r a g i n s , A. B., 2 4 S p r e e n , O., 26 S t r e e t e r , L. A . , 27-28 S w e t s , J. A . , 1 7

AUTHOR I N D E X

T

27 3

T a y l o r , G . A . , 26, 38-47 , 57-58, 68 , 9 3 , 1 0 5 , 1 3 1 , 2 4 8

T h o m p s o n , M . C . , 6, 57-58 , 6 2 T h o r n d i k e , L. L . , 2 5 T h u r s t o n , I . , 6 2 T i n k e r , M. A . , 11 T o w n s e n d , J. T . , 15 T o p p e r , G . E . , 27 T r a v e r s , J . R . , 1 2 7 - 1 2 8 , 1 3 1 T r e s s e l t , M. E . , 26, 48, 9 1 T u l v i n g , E . , 6 T u r v e y , M . T . , 56 T z e n g , 0. J . L . , 2 9

U

U n d e r w o o d , 8. J . , 25-26

V

V a c h e k , J . , 3 3 V e n e z k y , R . L . , 26, 29, 31, 33 , 35 , 38-47, 57-58, 9 6

W

W a l l a c h , M . A . , 24 Wang, W. S-Y., 2 9 W h e e l e r , D. D . , 6, 6 2 W h o r f , B . L . , 35 Wol in , B. R . , 26 W o o d w o r t h , R. S., 3

Y

Yonas, A . , 25-26, 29-30, 1 3 2

Subject Index

A

a c c u r a c y t a s k , 40 ,47 -48 , 56-61, 246-247 a n a g r a m , 3 8 a w a r e n e s s , 81

B

b i g r a m , 25-29 b i g r a m c o u n t s ,

c

c a t c h t r i a l , 39 c l a s s r o o m p r a c t

60-244

c e , 779 c o n f u s i o n m a t r i c e s , 14-15 c o n s o n a n t s p e l l i n g , 31-32

D

d e c i s i o n , 17-18 , 5 6 , 57 d ' m e a s u r e , 17-18

E

E n g l i s h n e s s , 127-128 e n v e l o p e , 15-16, 1 9

275

276 S U B J E C T I N D E X

F

f e a t u r e a n a l y s i s , 2 , 13-14 f e a t u r e d e t e c t i o n , 3-4 , 19-21 f e a t u r e d e t e c t i o n s t r a t e g y , 43-46, 6 8 , 71-73 f e a t u r e s , 3 , 5 , 1 4 , 14 -21 f o u r i e r a n a l y s i s , 1 9 f r e q u e n c y s c a l e , 130-132 f u l l r e p o r t , 6 , 24-25

G

g e n e r a t e d a b s t r a c t memory, 8

H

h i g h s p a t i a l f r e q u e n c i e s , 1 9 homophones , 3 3

i n f o r m a t i o n , 2 , 73-74 i n f o r m a t i o n p r o c e s s i n g m o d e l , 1-8, 55-62, 66-67

K

knowledge , 2 , 74

L

l e g i b i l i t y of t e x t , 11-13 l e t t e r - s o u n d c o r r e s p o n d e n c e s , 29-30 l e x i c o n , 8 l i n g i u s t , 34 long- t e rm memory, 3 , 8 low s p a t i a l f r e q u e n c i e s , 1 9

M

mask ing s t i m u l u s , 6 , 1 5 , 1 7 , 40 memory, 2-3 morpheme i d e n t i t y , 32 morphemic f e a t u r e s , 32-33

SUBJECT INDEX

N

nonword , 25

277

o r d e r e d a p p r o x i m a t i o n s t o E n g l i s h , 24-25 o r t h o g r a p h i c r e g u l a r i t y , 38 o r t h o g r a p h i c s t r u c t u r e , 2 , 4-9, 23-36 , 245 o v e r t j u d g m e n t s , 81 -90 , 247

P

p a r a l l e l p r o c e s s i n g , 5 , 56 p a i r e d j u d g m e n t s , 81, 87 -89 , 120-123 p e r c e p t u a l r e c o g n i t i o n , 8 p e r c e p t u a l u n i t , 5 p e r i p h e r a l v i s i o n , 1 3 , 1 5 , 1 9 p h o n o l o g i c a l c o n s t r a i n t s , 30-31 p h o n o l o g i c a l l y - b a s e d d e s c r i p t i o n s , 29-30 p o s i t i o n - i n s e n s i t i v e m e a s u r e , 1 3 2 p o s i t i o n - s e n s i t i v e m e a s u r e , 132 p o s t c u e , 47-48, 62-66 p r e c u e , 47-48 , 62-66 p r e p e r c e p t u a l v i s u a l s t o r a g e , 3-4, 56 p r i m a r y r e c o g n i t i o n , 4-5, 7 -8 , 56 p r i m i n g , 74 p r o c e s s , 2-3 p r o c e s s i n g t ime, 1 4 p s e u d o w o r d s , 24 , 82-85 , 115 p s y c h o l o g i s t s , 34

R

r a t i n g s , 81, 81 -87 , 113-119 r e a c t i o n - t i m e t a s k , 37-38 , 47-48 , 68-61 , 246-247 r e a d i n g , 1-2 r e a d i n g i n s t r u c t i o n , 1 - 2 , 247-248 r e c o d i n g , 8 r e d u n d a n c y , 6 r e h e a r s a l , 8 R e i c h e r - W h e e l e r p a r a d i g m , 6-7 , 40 r u l e - b a s e d d e s c r i p t i o n , 23-24 , 30-36, 3 8 , 9 6 , 1 2 9 , 247 r u l e - g o v e r n e d r e g u l a r i t y , 23-24, 30-36, 38 , 9 6 , 1 2 9 , 247

278 SUBJECT INDEX

S

s a c c a d e s , 3 s c r i b a l c o n s t r a i n t s , 31-32 s e c o n d a r y r e c o g n i t i o n , 4 , 8 s h o r t- t e rm memo r y , 7-8 s i m i l a r i t y , 43-46 , 51-54 , 64-65, 72-73 s i n g l e - l e t t e r p o s i t i o n a l f r e q u e n c y , 3 7 , 48 s i n g l e - l e t t e r p o s i t i o n a l f r e q u e n c y c o u n t s , 149-159 s p e e d - a c c u r a c y p a r a d i g m , 7 5 s p e e d e d RT t a s k , 75-82 s t a g e o f p r o c e s s i n g , 2-3 s t a t i s t i c a l r e d u n d a n c y , 23-29, 247 s t i m u l u s items, 97-98, 143-148 summed c o u n t s , 37 s y n t h e s i z e d v i s u a l memory, 8 , 56

T

t a r g e t l e t t e r , 37-39 t a r g e t s e a r c h t a s k , 3 7 , 37-81 t a r g e t t r i a l , 39 t e m p l a t e , 1 4 t e s t s t r i n g , 37-39 t o k e n c o u n t , 27-28, 128-130 t r i g ram , 27 t y p e c o u n t , 27-28, 128-130

V

vowel s p e l l i n g s , 31-32

w

word f r e q u e n c y , 1 4 1 word r e c o g n i t i o n , 1 -2 , 4

letter and word perception: orthographic structure and visual processing in reading

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