visual geometric properties in chinese character processing: a behavioural and event-related...
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Visual geometric properties in Chinese character processing: abehavioural and event-related potentialstudyTRANSCRIPT
Title Visual geometric properties in Chinese character processing: abehavioural and event-related potentialstudy
Author(s) Gao, Dingguo.; 高定國.
Citation
Issued Date 2003
URL http://hdl.handle.net/10722/36225
Rights The author retains all proprietary rights, (such as patent rights)and the right to use in future works.
Visual Geometric Properties in Chinese Character
Processing:
A Behavioural and Event-Related Potential Study
by
Gao Dingguo
A thesis submitted in partial fulfilment of the requirements for
the Degree of Doctor of Philosophy
at the University of Hong Kong
May 2003
Declaration
I declare that this thesis represents my own work, except where due
acknowledgement is made, and that it has not been previously included in a thesis,
dissertation or report submitted to this University or any other institutions for a
degree, diploma or other qualification.
Signed
Gao Dingguo
May 2003
Acknowledgements
First of all, I wish to acknowledge most humbly my indebtedness to Prof. Henry S. R.
Kao, my supervisor and mentor, for his encouragement, supervision and comments
during the past four years. I particularly value the daily discussions of Chinese
language and other issues in cognitive neuroscience studies of language with him
when I was in Hong Kong. My hope is that this study can somewhat provide an
empirical support to his psycho-geometric framework of Chinese reading and writing.
The results basically coincide with my hypotheses although some parts should be
tested or studied further in future.
Prof. Lin Chen generously provided me with a copy of all his work in topological
perception. The topological processing of Chinese characters in this study is based
on his theory that a primitive and general function of the visual system is the
perception of global topological properties. I was very much impressed by this
theory and decided to use it to study Chinese character processing. My current work
has benefited immeasurably from the thorough discussions with Prof. Chen when I
was in his Laboratory in Beijing as a visiting scholar in 1997 and 1998 respectively
and when he visited the University of Hong Kong during the last few years. I wish
to express my deep gratitude to him for all his help.
I sincerely thank Prof. Miao Danming and his colleagues, Drs. Liu Xufeng and Luo
Zengxue, and Ms. Wang Wei at the Fourth Military Medical University in Xi'an for
their kind assistance in recruiting subjects, collecting the behavioural and EEG data
and processing the imaging data. I in particular enjoyed the friendship that
developed during my stay there for conducting the experiments.
I would like to express my special thanks to Professor. Charles Perfetti, Dr. Li Hai
Tan and Dr. Zhou Xiaolin for their talks and presentations on Chinese language
research, and Ms. Chen Xuefeng for her assistance in collecting references and
bringing messages from my supervisor when I was not in Hong Kong.
I should acknowledge my admiration, affection and appreciation for my wife,
Ling-Hui, a computer scientist who not only gave me complete spiritual support over
the years, especially for her indulgence for my not helping with house work and the
endless pressure from our son Tian-Tian, a very active boy at his 14 months old when
I was writing the thesis, but also assisted in developing a database to analyse all the
Chinese characters in Chapter 3.
Finally, I am also indebted to the Graduate School, Chinese Language Cognitive
Science Research Centre, and the Department of Psychology of the University of
Hong Kong for the financial and physical support to the study.
Abstract of thesis entitled
Visual Geometric Properties in Chinese Character Processing:
A Behavioural and Event-Related Potential Study
submitted by
Gao Dingguo
for the degree of Doctor of Philosophy
at the University of Hong Kong
in May 2003
Chen (1982a, 1989) proposed a framework of visual perception based on the Klein
hierarchy of geometries (see Piaget, 1953) in which a primitive and general function
of the visual system is the perception of global topological properties and Kao (2000)
further developed a psycho-geometric theory of Chinese reading and writing on the
basis of Chen (1982a) and Ai (1948/1965) in which characters with balance, closure
and holes, linearity, centre of gravity, orientation, connectivity, symmetry, and
parallelism should be recognized and learned faster and/or more easily. The present
study investigated the effects of visual geometric processing in Chinese character
processing through a behavioural and event-related potential (ERP) approach
indicating some visual geometric properties facilitate the identification of Chinese
characters.
In Chapter 1, the author gives a brief introduction of Chinese characters and an
overview of the previous research related to the topic, and outlines the perspectives
what can be done in this thesis. In Chapter 2, the author defines topology,
symmetry, holes, and other geometrical features to be used in the thesis and discusses
the theories concerned. In Chapter 3, the author analyses the psycho-geometric
patterns of the most commonly used Chinese characters; he concludes that there is a
high density of holes, connectivity, linearity, balance and symmetry in these
characters. In Chapter 4, the results from two associated experiments exploring the
role of topological properties in identifying Chinese characters through a visual
matching task and a priming test are presented. The findings show a dissociation of
topology effects in which an effect was only found in Chinese characters with high
frequency in a visual matching paradigm and an effect was obtained in Chinese
characters with low frequency in a priming paradigm. In addition, no frequency
effect was found in both visual matching and priming tests. Chapter 5 is an account
of four relatively independent experiments conducted to show whether the
geometrical properties identified in Chapter 3 are the primitive factors to affect
Chinese character judgement in a lexical decision paradigm. Experiment 3a-d
revealed a symmetry effect, a closure effect and a structure effect but not a linearity
effect which was found only in Chinese characters with low frequency. In addition,
a significant frequency effect was found in all four conditions. Chapter 6 reports on
the results from two event-related potential experiments to show the association of
brain activation with topological and symmetrical processing of Chinese characters.
Experiment 4 replicated the results by the above behavioural studies and found an
early occurrence of ERPs in processing topological properties. Experiment 5 showed
a similar pattern of processing symmetric properties in the behavioural study. Some
brain patterns of processing geometric properties based on the time course of ERPs
have been found to be associated with the above processing, say, the topological and
symmetrical processing. Chapter 7 is a general discussion to integrate all the issues
in which a psycho-geometric theory and a holistic processing view have been
addressed in detail, and a summary of all the investigation and experiments done in
the thesis.
Contents
Declaration
Acknowledgements i
Table of contents iii
Chapter 1 Introduction 1
1.1 Chinese characters: A unique written language 1
1.2 What features determine the identification of a Chinese character .... 2
Chapter 2 Research background 6
2.1 What is topology 6
2.2 What is symmetry 8
2.3 What are connectivity, linearity, closure and structure 11
2.4 Objective and organisation of the dissertation 14
Chapter 3 Psycho-geometrical analysis of the commonly used Chinese
characters 17
3.1 Introduction 17
3.2 Method 19
3.3 Results 20
3.3.1 Structure of the Chinese Character 20
3.3.2 Frequency of Usage and Number of Strokes 21
3.3.3 Holes 23
3.3.4 Connectivity 24
3.3.5 Linearity 25
iii
3.3.6 Symmetry 25
3.3.7 Balance 27
3.4 Summary 27
Chapter 4 Topological processing of Chinese characters 29
4.1 Experiment 1 31
4.1.1 Method 31
4.1.2 Results 34
4.1.3 Discussion 36
4.2 Experiment 2 38
4.2.1 Method 38
4.2.2 Results 40
4.2.3 Discussion 41
Chapter 5 Psycho-geometrical processing of Chinese characters 43
5.1 Experiment 3a 44
5.1.1 Method 44
5.1.2 Results 46
5.2 Experiment 3b 48
5.2.1 Method 48
5.2.2 Results 50
5.3 Experiment 3c 52
5.3.1 Method ••••• 52
5.3.2 Results 54
IV
5.4 Experiment 3d 55
5.4.1 Method 56
5.4.2 Results 57
5.5 Discussion 59
Chapter 6 Topological and symmetrical processing of Chinese characters:
An event related potential study 63
6.1 Introduction 63
6.2 Experiment 4 64
6.2.1 Method 64
6.2.2 Results 66
6.2.2.1 Behavioural data 67
6.2.2.2 ERP data 67
6.2.3 Discussion 69
6.3 Experiment 5 71
6.3.1 Method 72
6.3.2 Results 74
6.3.2.1 Behavioural data 74
6.3.2.2 ERP data 75
6.3.3 Discussion 79
Chapter 7 General discussion and summary 81
7.1 Psycho-geometric theory of Chinese character reading 81
7.1.1 Chinese characters and the characters structuring 81
V
7.1.2 Principles of Chinese character writing 83
7.1.3 Effects of character geometricity on visual recognition 84
7.2 Topological perception and functional hierarchy in form
perception 88
7.3 The neural mechanism of geometric property processing:
Evidence in topology and symmetry 93
7.4 Present and future 94
7.4.1 Implications 94
7.4.2 Limitations 95
7.2.3 Present and future directions 95
7.5 Summary
References 101
Appendix A 117
Appendix B 118
Appendix C 118
Appendix D 119
Appendix E 120
Appendix F 121
Appendix G 122
Appendix H 123
Appendix I ••••• 133
Appendix J 134
CHAPTER 1
INTRODUCTION
1.1 CHINESE CHARACTERS: A UNIQUE WRITTEN LANGUAGE
The Chinese writing system is unique in the world. Written Chinese or Chinese
characters are different in many aspects from the alphabetic written language. First, each
character is composed of strokes that are arrayed vertically and horizontally, and
occupies almost the same space as others, while an alphabetic word usually consists of
horizontally distributed alphabets. Second, all Chinese characters are monosyllabic and
have no syllables that do not carry a meaning except for a few exceptions, e.g., #1-44
(kel1 dou3-tadpole) in which $$• and 44 do not mean anything but $1444 means tadpole.
More importantly, although there are many phonograms in the Chinese language, it is
difficult to orthographically spell out a character, regardless of the experience in
orthography and correctness of pronunciation. Thirdly, a Chinese character is usually
composed of a phonetic determinative (or phonetic radical) and a semantic
determinative. Semantic radicals in a Chinese character strongly imply the meaning and
classification. For instance, if a character has a radical (yu2-fish), it is almost certain
this object will be a kind of fish, an animal which is living under water, or something
related to a fish. Although there are word-stems in alphabetic words, it is more common
for a Chinese character to carry such a radical. Finally, Chinese characters comprise
geometric structures, such as holes, squares, straight and oblique lines, dots and curves.
According to a psycho-geometric framework (Kao, 2000), this construction should be
easy to attract your attention to focus on the presented Chinese character. For detailed
discussion of Chinese characters, please see Ann (1987), Boltz (1994), Hoosain (1991),
Wang (1973) and Zhou (1998).
1.2 WHAT FEATURES DETERMINE THE IDENTIFICATION
OF A CHINESE CHARACTER?
1.2.1 Previous Work in Chinese Character Processing
In the past two decades, psychologists and linguists had conducted studies on
how people identify Chinese characters or what factors influence the processing.
Much attention has been drawn to debate whether phonology or morphology
occurs earlier or whether Chinese character identification is different from that of
alphabetic words. For example, some researchers found the phonology of a
Chinese character is crucial to access its meaning representation (access to the
lexicon), and the phonology of a Chinese character is activated at a very early
stage or to some extent is processed automatically (Cheng and Shih, 1988;
Perfetti and Tan, 1998; Perfetti and Zhang, 1991, 1995; Tan, Hoosain, and Siok,
1996; Lam, Perfetti, and Bell, 1991; see a review by Perfetti, Liu & Tan, in press).
This view of phonology-plus-meaning process was challenged by a script-to-
meaning view of Chinese reading (Chen, Yung, & Ng, 1988; Hoosain, & Osgood,
1983; Tzeng, Hung, & Wang, 1977; Zhou, 1997) and a dual route model in which
either a visual or a phonological path leads to the activation of the meaning of a
word (Coltheart, 1978; Plaut, McClelland, Seidenberg & Patterson, 1996;
Seidenberg, 1985; Seidenberg & McClelland, 1989). However, few studies have
paid attention to other issues of Chinese characters, e.g., the visual form of a
character and perceptual features in recognising a character.
1.2.2 Previous Work for Geometry in Perception
Ai (1948/1965) argued in his book "Issues in Chinese characters" that characters
with symmetric, closed, and/or linear (horizontal and/or vertical lines) features or
with less than ten strokes are recognized more easily than those with other
configurations. Zeng's investigation on Chinese characters also echoed this view
(Zeng, 1983). Kao (2000) has further developed a psycho-geometrical theory of
reading and writing Chinese characters, in which characters with balance, closure
and holes, linearity, centre of gravity, orientation, connectivity, symmetry, and
parallelism should be recognized and learned faster and/or more easily.
In fact, some studies in visual perception have shown that physical properties of a
stimulus play an important role in visual identification, especially in a
tachistoscopic environment. Chen (1982a), for instance, found that the
topologically equivalent objects are more difficult to distinguish than the
topologically different counterparts and thus advanced a hypothesis of
topological perception in which a primitive and general function of the visual
system is the perception of global topological properties (Chen, 1985, 1989; Todd,
Chen, & Norman, 1998).
In addition, everyday experiences and much empirical evidence have also
indicated that symmetry, one of the geometric features that constitute a Chinese
character, is an important visual primitive and facilitates processing in vision.
Research, for example, has shown that the presence of symmetry in a pattern or
visual composition can be detected more quickly than its absence, and some types
of symmetry, such as bilateral symmetry, are more readily verifiable than others
(see, for instance, Ballesteros, Millar & Reales, 1998; Baylis & Driver, 1994;
Biederman, 1987; Bruce & Morgan, 1975; Koffka, 1935; Locher & Nodine, 1989;
Marr, 1982; Wenderoth, 1997). Attneave (1957) and Day (1968) also found
symmetrical shapes were judged less complex than asymmetrical shapes with the
same total number of turns (sides) by approximately one standard deviation unit.
From the above review, it is understandable that these geometric features may
affect the processing of a Chinese character, given the unique construction of
Chinese characters that can be visually defined as a geometric figure, and the
previous empirical evidence in perception.
1.2.3 The issues for processing Chinese character: From geometry view
Chinese characters are undoubtedly composed of geometrical figures, such as dot,
square and line. The questions arising from the above overview are:
• Given the Chinese characters' geometrical features, what is the mathematical
distribution of geometricity of the commonly used Chinese characters?
• Do topology, symmetry, linearity, closure and structure (form arrangement)
play a role in identifying a Chinese character? Further, is there any
dissociation among the conditions, e.g., frequency, tests, and presentation
time?
• What is the association between the cortex activation and the processing?
Could we physiologically and psychologically demonstrate this association?
CHAPTER 2
RESEARCH BACKGROUND
2.1 WHAT IS TOPOLOGY?
Topology, a geometry developed by a German mathematician, Felix Klein, in his lecture
of 'Erlangen Programme' in 1872, is intended to study those properties that an object
retains under deformation—specifically, bending, stretching and squeezing, but not
breaking, cutting or tearing, which is called topological transformations. 'Knotted' is
typically a topological concept because you cannot untie a knot in closed loop by
stretching or bending it. Thus a triangle is topologically equivalent to a circle but not to
a straight-line segment. Similarly, a solid cube made of modelling clay could be
deformed into a ball by kneading. It could not, however, be molded into a sold torus
(ring) unless a hole were bored through it or two surfaces were joined together. A solid
cube is therefore not equivalent to a finger ring. Topological equivalence is defined
based on the invariants, such as connectivity/separation, closure and holes, and inside
and outside distinctions under topological transformations. More precisely, if there are
given two geometric objects or sets of points and if some two-way transformation takes
each point p of each set into one and only one point p' of the other and if the
transformation is continuous in the sense that points close to p become points close to p
then the transformation is called a homeomoxphism and the two sets are said to be
topologically equivalent. In general, topology is the study of properties that remain
invariant under homeomorphisms.
However, the deformation concept has certain limitations. If two figures are given in
Euclidean 2-dimensional space, called2 ~ that is, the space of ordinary plane geometry—
and if one of them comprise a circle tangent internally to a larger circle and the other is
composed of two externally tangent circles, then a homeomorphism exists that
transforms one figure into the other and therefore the two figures are topologically
equivalent. However, one figure cannot be changed to the other by distortion in 2. It is
possible to turn one of the circles through 180° around the common tangent line as axis,
thus carrying it into 3-dimensional space 3, and effecting the deformation. The extra
dimension may or may not be available, depending on the conditions of the problem. An
internally tangent sphere in 3 could be continuously deformed to bring it to a position of
external tangency by a rotation in hypothetical 4-dimensional space 4, which might
present no difficulty mathematically but would be impossible to achieve or even
visualize in a physical application. The mathematical context may also prevent the use
of an additional dimension. In any case, the deformation concept is not used or needed
in defining topology. For a detailed understanding of topology, see Aleksandrov,
Kolmogorov and Lavrent'ev (1963).
Chen (1982a, 1985; Todd, Chen, & Norman, 1998) argued that a primitive and general
function of the visual system is the perception of global topological invariants.
Evidence for this hypothesis has been supported by the studies in apparent motion (Chen,
1985), 3D form discrimination (Todd, Chen & Norman, 1998), object-superiority effect
(Weisstein & Harris, 1974; McClelland, 1978; Williams & Weisstein, 1978; Chen,
1982b), grouping (Olson & Attneave, 1970; Pomerantz, Sager & Stoever, 1977; Chen,
1982c), card sorting (Palmer, 1978), effortless texture discrimination (Julesz, 1981),
visual sensitivity to distinction in topology (Pomerantz, 1980; Chen, 1982a) and
competitive organization with simultaneous factors (Chen, 1982d).
One of the objectives of the present study aimed to explore whether topological
properties affect processing Chinese characters, or whether the above hypothesis by
Chen (1982a) applies to Chinese character identification.
2.2 WHAT IS SYMMETRY?
The word 'symmetry' is used in our everyday language with two meanings. In one
sense, 'symmetry' means something like 'well-proportioned, well-balanced' and
'symmetry' denotes that sort of concordance of several parts by which they integrate
into a whole. In a word, beauty is associated with symmetry. In another sense,
'symmetry' can be mathematically defined. In fact, bilateral symmetry, the commonest
symmetry, is used more frequently.
Symmetry of an object is a transformation that leaves it apparently unchanged. The
number and type of such transformations depend on the geometry of the object to which
the transformations are applied. The meaning and variety of symmetry transformations
may be illustrated by considering a square lying on a table. In all patterns there are four
basic symmetry transformations or rigid motions: translation (rigid motion with
repetition along a line), reflection (rigid motion with repetition across an axis), glide
reflection (rigid motion with reflected repetition along a line), and rotation (rigid motion
with repetition around a point). A circle would be regarded to have higher symmetry
because, for instance, it could be rotated through an infinite number of angles (not just
multiples of 90 degrees) to give an identical circle.
In this study, we mainly focused on bilateral symmetry of Chinese characters. Bilateral
symmetry can be precisely defined as: A shape is bilaterally symmetric if there exists
some reflection that leaves it invariant - that is, unchanged in appearance. What is clear
is that a mathematically symmetrical object is not necessarily visually beautiful although
this is not generally taken note of, because this definition does not capture its aesthetic
aspects very well and imperfections that destroy mathematical symmetry may add
aesthetic value somehow (This issue will not be discussed in the study).
For Chinese characters, symmetry takes place through reflection and translation. Most
of the symmetric Chinese characters are of bilateral symmetry type. Some characters
are bilaterally symmetric through a vertical axis, e.g., (xinl-hot) and "H" (zai4-
again) and some through a horizontal one (The case can also be named as vertical
symmetry although it is a variation of bilateral symmetry), e.g., "HI" (po3-forbidden)
and "]=[" (ju4-large). However, symmetry in Chinese characters also appears through
translation, e.g., (lin2-forest) and "M" (peng2-friend). As described before,
symmetry is an important visual primitive and has been proved to facilitate processing
in visual perception (Attneave, 1957; Ballesteros, Millar & Reales, 1998; Baylis &
Driver, 1994; Biederman, 1987; Bruce & Morgan, 1975; Day, 1968; Koffka, 1935;
Locher & Nodine, 1973, 1989; Marr, 1982; Wenderoth, 1997). Given that a large
amount of Chinese characters are symmetric, it would be reasonable to hypothesise that
symmetry is a crucial and primitive feature in processing Chinese characters, especially
in the early stage of the process. Research, for example, has shown that the presence of
symmetry in a pattern or visual composition can be detected more quickly tb^ri its
absence, and some types of symmetry, such as bilateral, are more readily verifiable than
others (see, for instance, Ballesteros, Millar & Reales, 1998; Baylis & Driver, 1994;
Biederman, 1987; Bruce & Morgan, 1975; Koffka, 1935; Locher & Nodine, 1989; Marr,
1982; Troje & Buelthoff, 1998; Wenderoth, 1997). Furthermore, consideration on
symmetry has been drawn to an evolution theory in which preferences for symmetry
have evolved in animals because the degree of symmetry in signals indicates the
signaller's quality, and may arise as a by-product of the need to recognise objects
irrespective of their position and orientation in the visual field (Enquist & Arak, 1994).
This may account for the observed convergence on symmetrical forms in nature and
decorative art.
The second objective of the present study was to analyse a character through the
classification of symmetry, including near symmetry as it was hard to determine a
strictly mathematical symmetry in Chinese characters, and test whether symmetry would
facilitate processing symmetrical Chinese characters more quickly than asymmetrical or
near-symmetrical characters.
10
2.3 WHAT ARE CONNECTIVITY, LINEARITY, CLSOURE, AND
STRUCTURE?
Both Ai (1948/1965) and Kao (2000) argued that Chinese characters with symmetry,
closure, holes, centre of gravity, orientation, connectivity, parallelism and/or linear
(horizontal and/or vertical lines) features should be recognized more easily than those
with other configurations. Kao (2000) further developed a psycho-geometrical theory of
reading and writing Chinese characters based on the above consideration. According to
Kao (2000), central to the perceptual organization of the character form are some
properties underlying the visual-spatial structure of Chinese characters. The visual
frame can be analysed from the perceptual elements of shape, form, space, and balance.
On a more visual spatial level, several geometrical principles of visual perception are
pertinent to the cognitive map of the character produced in and by the act of reading.
These include connectivity, inside-outside distinctions, holes, co-linearity, orientation
and symmetry. Characters sharing these visual-spatial properties are predicted to
process more efficiently, say, faster or more accurately, than those characters sharing
less of these properties. A conceptual framework has been developed to describe the
highlights of the above observations within a systematic analysis of the components of
Chinese characters.
In this study, we selected a few salient features including connectivity, linearity, closure
and holes, and left-to-right or top-to-down structure to conduct our investigation.
11
2.3.1 Holes
A hole can be operationally defined as an entity consisting of a finite line (straight,
cursive or mixed) without an end point. One of the most apparent features of a hole is
closure which is seen as one of three fundamental properties of topological geometry
(the other two are connectivity and inside and outside relations, see Chen, 1989).
According to Chen (1982a, 1985) and Todd, Chen and Norman (1998), a primitive and
general function of the visual system is the perception of global topological properties
and the relative perceptual salience of object properties may be systematically related to
their structural stability under change, in a manner that is similar to the Klein hierarchy
of geometries. That is, the processing of topological feature is earlier than those of
Euclidean, affine and projective geometrical features. Piaget (1953) even found
topological ideas, which include proximity, separation, order, enclosure, and continuity,
developed earlier in children than the Euclidean. In fact, one of the methods to construct
a Chinese character is topological transformation under which two characters are
topologically equivalent (see Liu, 1993). A hole can centralize people's vision in a
frame and thus receives the most attention (Casati & Varzi, 1994). On the above studies,
it is assumed that there will be a superiority effect in perceiving, recognizing and
learning a Chinese character with hole(s) or with a closure structure.
2.3.2 Connectivity
Connectivity refers to an entity without separation. Objects connected with each other
would be more probable to be perceived as a whole according to Chen (1989) and
12
Koffka (1935). According to a topological processing view, whether an entity is
continuous or separated is very easy to judge. There are some Chinese characters with
the property of connectivity, e.g. " I " (wei4-protect) and "Hi" (mian4-face).
2.3.3 Linearity
In line with Ai's research (1948/1965), in this study Chinese characters consisting of
75% of straight lines or over, including horizontal or vertical such as "IE" (zheng4-
correct) and "^."(shengl- birth) were defined as having high linearity and those with
75% of curves or over, including dots and oblique lines such as "^"(cai3-exploit) and
"$£"(jiao3-cunning) as having low linearity. A Chinese character with high linearity is
supposed to be recognized more easily than a character with low linearity.
2.3.4 Closure
In the present study, closure means that a Chinese character is composed of a closed
frame which fully embeds other components of this character. 15 (wei2)-surround and
IS (guo2)-nation, for example, are typically structured with closure. A completely
closed Chinese character, e.g., "HI" (hui2-return), is quite different from " Jr]" (xiang4-
towards) in a topological view although they are morphologically similar.
2.3.5 Structure
13
Most of the Chinese characters are shaped with left-to-right, e.g., ttf (hao3-good) or top-
to-down structure, e.g., (wu4-must). As human vision is accustomed to search from
left-to-right instead of top-to-down (See Gazzaniga, 1998 and Marr, 1982 for an
introduction), it is reasonable to suppose that the characters with a 1 eft-to-right form
would be recognised better than other forms.
2.3.6 Brief Summary
While we have identified the visual primitives in Chinese characters, we should be
cautious in making any firm conclusion before further empirical evidence is given.
Chinese character identification is, after all, not a purely perceptual process. It may
involve phonological and semantic processes, and even affection and emotion. The
present study will try to avoid some distractions to work towards a dissociation of the
above visual properties through both a behavioural and a neuroimaging (ERP) approach.
2.4 OBJECTIVES OF THE STUDY AND ORGANISATION OF THE
DISSERTATION
2.4.1 Objectives of the Study
There are three main objectives in this study:
14
• To investigate the psycho-geometric features of the most commonly used Chinese
characters
• To examine whether topological properties affect Chinese character processing
through a behavioural and event related potential (ERP) approach
• To test whether symmetry, linearity, closure and left-to-right or top-to-down
structures influence Chinese character processing through a behavioural and ERP
approach
2.4.2 Organisation of the Dissertation
The dissertation is basically organised into seven chapters. In Chapter 1, the author
gives a brief introduction of the history of Chinese characters, provides an overview of
research related to the topic, and advances the perspectives what can be done in this
thesis. In Chapter 2, the author makes a detailed description of the definitions of
topology, symmetry, holes, and other geometrical features to be used in the dissertation
and discusses the theories concerned. He also states the objective of the thesis. In
Chapter 3, the author analyses the most commonly used Chinese characters in modern
Chinese language in a psycho-geometrical framework in which the author will select
structure, connectivity, holes and closure, linearity, balance and symmetry as indexes.
Chapter 4 reports on two associated experiments conducted to test whether topological
properties affect Chinese characters processing through a visual matching task and a
priming test. Chapter 5 reports on four relatively independent experiments carried out to
investigate whether the analysed geometrical properties in Chapter 3 are the primitive
15
factors to Chinese character judgement in a lexical decision paradigm. In Chapter 6,
the author presents the results from two event-related potential experiments to explore
the association of cortex activation with topological and symmetrical processing. In
Chapter 7, the author summarises all the investigation and experiments done in this
study and gives a general discussion.
16
CHAPTER 3
PSYCHO-GEOMETRIC ANALYSIS OF
THE COMMONLY USED CHINESE CHARACTERS
3.1 INTRODUCTION
Although there are almost one hundred thousand Chinese characters, which have been
used across different historical periods (see Wan & Hsia, 1957; Zhou, 1999), there are
only around 5,000 characters or fewer in active usage in modern Chinese (e.g., Ann
1986; Suen, 1986; Wang & Chang, 1986). According to Ann, 3,500 most frequently
used characters in Hong Kong cover 99.80% of the common usage of Chinese
characters. That is, a person would be able to read 99.80% of all the characters
contained in selected texts in a 1000-character article if she/he masters these 3500
characters. The finding was echoed on the Chinese mainland that 3,500 characters
occupy 99.87% of usage and with a skewed distribution on frequency of usage as
summarized in Table 1 (Wang & Chang, 1986).
Table 1
The skewed distribution of the frequency of usage of Chinese characters
Chinese characters (descending in frequency)
10 20 50 100 116 500 1000 1619 2000 3000 3156 3500 4000 4754
C.F. 15.85 23.10 35.08 47.70 50.24 79.76 91.37 96.60 98.07 99.63 99.73 99.87 99.96 100
Note: C. F. referred to cumulative frequency (%). (Source: Wang & Chang, 1986)
17
As a result, it is important to analyse the perceptual or orthographic features of these
commonly used Chinese characters in order to help people learn Chinese. A conceptual
framework developed by Kao (2000) was advanced to highlight the above observations
within a systematic analysis of the components in each Chinese character. The main
points in the psycho-geometric approach to Chinese character reading are presented
below.
At the body-character interface, some visual-spatial patterns are more salient or
important than others. They are those closely reflecting or conforming to basic
topological properties of visual perception. Fundamentally, a Chinese character should
be seen to portray an imaginary or visible rigid square, although modern forms may be
written within a rectangular shape. A square is the perfect geometric pattern as it
incorporates hole, linearity, symmetry, parallelism, connectivity and/or orientation. With
an implied correspondence between the shape of the square and the symbol, characters
may vary in terms of the extent to which they possess the geometric properties of the
square.
Cognitive changes associated with the geometric variations of the characters include
clerical speed and accuracy, spatial ability, abstract reasoning, digit span, short-term
memory, picture memory, and cognitive reaction time and accuracy.
Stylistic variations of Chinese characters reflect individualized forms of strokes
organization in the character. The patterns of geometricity in the character may include:
18
Shape, e.g., A (triangle), • (square), • (rectangle); size; balance (e.g., £?); closure and
holes (singular or plural, e.g., • , kou3 - mouth, @, mu4 - eye); linearity (e.g., IE,
zheng4 - right); centre of gravity (e.g., ®, hui2 - return); orientation (e.g., fjj, shanl -
mountain); connectivity (e.g., gongl - bow); symmetry (e.g., zu2 - soldier, H
men2- door); parallelity (e.g., H , er4- two, H , sanl- three); inside-outside distinctions
(e.g., @1, kun4 - trap vs. dail - retarded), and global and detailed figures.
The present investigation aimed to establish a database and analyse the most commonly
used Chinese characters in modern Chinese through a psycho-geometric approach (Kao,
2000).
3.2 METHOD
3.2.1 Source of the Selected Chinese Characters
A set of 4,575 most frequently used Chinese characters was extracted from 'A frequency
dictionary in modern Chinese' (Wang & Chang, 1986), which has been a widely cited
handbook in Chinese language research. These characters represented a total of
1,808,114 characters selected from: a) articles in politics, economy, philosophy, history,
military affairs and so on in popular newspapers, magazines and periodicals, b)
scientific articles which focus on the issues of daily life, c) spoken materials from drama,
libretto and scenario, commentaries, and songs, d) novels, essays and tales, and e)
articles from elementary and secondary school textbooks.
19
3.2.2 Data Collection and Analysis
All the data of the selected characters were compiled by Foxpro and processed by SPSS.
In the present investigation, only the structure, stroke, hole, connectivity, linearity,
symmetry and balance of a Chinese character were analysed.
3.3 RESULTS
3.3.1 Structure of the Chinese Character
Table 2 Distribution of different structures
Structure of the Chinese characters
a b c d e f g h l J
First 100 30 18 1 6 6 1 1 0 0 37
First 500 202 129 5 22 18 5 3 1 1 114
Total (4573) 2823 1028 23 192 117 45 33 14 6 293
Note: a, b, c, d, e, f, g, h, i, and j refers to the structure feature of a character.
According to Fu (1993), Chinese characters are basically classified into ten types in
structure, which were showed as follows: a) left-right (^fl - and), b) top-down ( ^ -
word), c) fully closed ( 0 - return), d) partially surrounded with roof and left flank (11 -
press), e) partly surrounded with floor and left flank (iH - arrival), f) partly surrounded
with roof and right flank ('rJ - sentence), g) surrounded without floor (|W] - same), h)
surrounded without right flank (Ee - great), i) surrounded without roof (!><! - violent), and
j) independent ( ^ - centre). Some researchers also roughly defined all the d, e, f, and g
20
structures as the partially surrounded. We found all the selected characters can be
categorized into the ten groups mentioned above (see Table 2).
The results revealed that over 60% of Chinese characters are of left-right structure,
around 20% of top-down and less than 20% of other structures. Although the first two
kinds of structures dominate the distribution, among the first 100 Chinese characters
descending in frequency and covering 51% of usage, the characters with independent
structures, in which most are connected in strokes, are of 37% (37 occurrences) and
among the first 500 characters which cover almost 70% of usage, 22.8% (114
occurrences in total) respectively.
3.3.2 Frequency of Usage and Number of Strokes
Loo (1989) found the frequency of characters, whether they are simplified or traditional,
is inversely proportional to the number of strokes. The more frequently the characters
are used, the fewer strokes they will have. This implies the simplification movement of
Chinese characters advocated in the Chinese mainland since the 1950's was reasonable.
In addition, simplified characters have around 22.50% fewer strokes than the traditional
form, which may translate into cost savings in the printing industries and time saving in
manual writing and facsimile transmission. However, the psychological or cognitive
effect with reference to this should be further investigated before a firm conclusion is
made. Simplification may have damaged the good form which existed in a traditional
Chinese character. For instance, the simplified form of ^ (chel-car) is asymmetric, less
21
parallel and linear comparing to its traditional form, i f . Cheng (1997) compared the
2173 simplified characters with the traditional counterparts and found a 1.8-stroke
savings per character on average in these simplified characters, indicating writing these
characters would save 1.8 hand movements per character. Simplification, however,
generates a number of visually similar characters and polysemies which would make
reading Chinese difficult.
Table 3
Correlation of Frequency and Stroke and Mean Strokes
High-frequency Mid-frequency Low-frequency Total
Pearson Correlation -0.196(1621) -0.129(1591) -0.011 (1362) -0.183 (4574)
Mean Strokes 8.66 (3.12) 10.59 (3.42) 11.45(3.69) 10.16(3.59)
Note: numbers in the brackets of the second row is the characters used; and the numbers in the brackets of the thirds row is the standard deviations.
Table 3 showed the correlation of frequency2 and stroke number. Interestingly, for low
frequency characters, almost no correlation existed between frequency and stroke
number, but the high and mid frequency parts did show some correlation (0.196 and
0.129 respectively and both reached a significant level, a = 0.05). This result coincided
with the skewed distribution of frequency of Chinese characters in which low frequency
characters were extremely rarely used and thus a low correlation was obtained.
Although at present it was premature to conclude whether simplified Chinese characters
are easier or more difficult to learn, this finding and the fact that simplified Chinese
characters were given official writing system status on the Chinese mainland and
Singapore suggested that simplified characters would at least not be inferior to
22
traditional Chinese characters currently used in Hong Kong, Macao and Taiwan. For
high frequency characters, there were about 2 strokes fewer than those with mid-
frequency or around 3 strokes fewer than those with low frequency characters. The
results were consistent with those in Loo's and Cheng's studies (Cheng, 1997; Loo,
1989).
3.3.3 Holes
Casati and Varzi (1994) believed that the way a hole can be filled receives the most
attention and undoubtedly holes play an important role in the organisation of visual
perception. Fu (1999) reported that out of 11,834 characters in total there are 20.34% of
Chinese characters consisting of the radical' P ' (kou3-mouth), which is typically a hole
and much more than other radicals or components. Holes are one of the most salient
topological properties (Casati & Varzi, 1994) and appear commonly in Chinese
characters. Table 4 showed the distribution of holes in Chinese characters.
Table 4
Holes in the selected Chinese characters
Number of Holes
1 10 11 12
HF
MF
LF
Total
662
522
417
1601
389
365
291
1045
265
278
281
824
139
191
141
471
110
146
118
374
36
47
65
148
14
28
21
63
4
8
17
29
1 5
5
11
1 0 1 0 2 2
4 2
Note: HF refers to high frequency, MF to mid-frequency and LF to low frequency.
Table 4 presented the holes in the total 4574 characters. It showed that 65% of
characters contain hole(s) ranging from 1 to 12, and among those with hole(s), most
23
consist of 1 or 2 holes, indicating most of the commonly used Chinese characters consist
of hole(s). The distributions of holes across frequency are 959 characters (59%) for high
frequency, 1,069 (67%)for mid-frequency and 945 (69%) for low frequency.
3.3.4 Connectivity
Table 5
Number of characters with connectivity
Order of the characters descending in frequency
100 200 300 500 1000 Total
Connected 33 62 88 116 167 275
HF 196
MF 54
LF 25
Disconnected 67 138 212 384 833 4299
HF 1425
MF 1537
LF 1337
Note: HF refers to high frequency, MF to mid-frequency and LF to low frequency.
It is known that connectivity is also one of the approaches to create a character. The
distribution of the connected characters was extremely skewed (see Table 5). Among
the first 300 characters, around 30% of them are connected and 71% of the connected
characters are of high frequency while only 6% of the totally selected 4575 characters
hold this feature, suggesting the most frequently used Chinese characters are connected.
As most of the connected characters are of du-ti-zi or the monosomatic, the results were
in fact consistent with the investigation for monosomatic characters (see also Table 2).
The results from these two investigations suggested that the connected Chinese
characters be easier to learn because the most frequently used characters might be the
24
easiest to read according to a principle of economy in learning. Again, further
behavioural and developmental evidence was needed.
3.3.5 Linearity
It is a fact that the most commonly used strokes in Chinese characters are straight lines.
Table 6 showed there are 260 characters with high linearity (75% lines or over in a
character) and 212 with low linearity (25% lines or less in a character). The results
indicated that both high and low linearity characters are not much common in the
frequently used Chinese characters. In addition, although no difference in linearity
across the frequency of the usage of characters was found, it might not apply to the case
of traditional Chinese characters as the simplification of Chinese characters might have
changed the linearity.
Table 6
Distribution of the selected Chinese characters across linearity
Linearity High-frequency Mid-frequency Low-frequency Total
High 115 76 69 260
Low 103 65 44 212
3.3.6 Symmetry
In the present study, I classified the Chinese characters as symmetric (bilaterally and
vertically), near-symmetric and asymmetric according to the definition of symmetry.
Near-symmetry means some part(s) are symmetric although the whole character is
25
asymmetric. It is hard to define a strictly mathematical symmetry in Chinese characters,
especially in those characters with low frequency. To illustrate, # (lin2-forest) is
bilaterally symmetric, [[6 (za3-bundle) is nearly symmetric, meaning one or more
components in a character are symmetric but the whole is asymmetric, and ^ (gai4-
beggar) is asymmetric.
Table 7
Distribution of symmetry in the selected Chinese characters
Bilateral symmetry Vertical symmetry Near-symmetry Asymmetry
High-frequency 172 5 505 939
Mid-frequency 81 5 518 987
Low-frequency 53 3 450 856
Total 306 13 1473 2782
Note: The data of some characters with both bilateral and vertical symmetries are only regarded as bilateral symmetry, such as " 0 " (sun).
The results from table 7 showed that around 7% of characters are fully symmetric (11%
among high frequency characters), 32% are nearly symmetric (31% among high
frequency) and 61% are asymmetric (58% among high frequency characters). In
addition, nearly symmetric or asymmetric characters are approximately equally
distributed across the frequency of usage. There exist some characters with both
bilateral and vertical symmetries. They are shown as follows: "—" (yil-one), "X"
(gonl-work), "cf3" (zhongl-centre), "-f-" (shi2-ten), " H " (sanl-three), " ® " (hui2-
return), (koul-mouth), " 0 " (ri4-sun), " g " (mu4-eye), "ffl" (tian2-field), " i "
(wang2-king), "]t[" (chuanl-river), (fengl-many), (shenl-claim), "El" (yue4-
say), "jtt" (sa4-thirty), "M" (e4-bad) and (feil-false). In fact, there are other cases
26
that a character contains more than one symmetry such as bilateral plus repeated
(through translation), e.g., "J | " (jingl-light), "pp" (pin3-quality), " i t " (chu4-stand), and
"M." (shuangl -double).
3.3.7 Balance
Ai (1948/1965) argued that if a character with left-right structure has 13 or more strokes
and the stroke difference between the two sides are over 10, the character should be
difficult to read and write. The author defined this feature as the balance of a Chinese
character. A character meeting Ai's definition would be named as having weak balance.
There are in total 86 characters of this type with 9 of high frequency, 31 of mid-
frequency and 46 of low frequency.
3.4 Summary
Over 60% of Chinese characters are of left-right structure, around 20% of top-down and
less than 20% of other structures. In general, the frequency of characters is inversely
proportional to the number of strokes, i.e., the more frequently the characters are used,
the fewer strokes they will have. However, for low frequency characters, almost no
correlation exists between frequency and stroke number. For high frequency characters,
27
they will be about two strokes fewer than those with mid-frequency or around three
strokes fewer than those with low frequency.
Most of the frequently used Chinese characters (65% in total) contain hole(s), with most
of them having 1 or 2 holes. No apparent difference is revealed in the distribution of
hole(s) across frequency (59% for high frequency, 67% for mid-frequency and 69% for
low frequency).
Only 6% of the characters are connected in construction but the distribution of this
property (characters with connectivity) is extremely skewed. Among the first 300
characters around 30% of them are connected and 71 % of the connected characters are
of high frequency, suggesting that the most frequently used Chinese characters are
connected.
There are 260 characters with high linearity and 212 with low linearity but this finding
may not apply to traditional Chinese characters. Thirty-nine percent of the characters
are fully or partially symmetric and most of the fully symmetric characters are of high
frequency. Partially symmetric or asymmetric characters are approximately equally
distributed across the frequency of usage. There exist some characters with two or more
symmetries. Moreover, there are 86 characters in total with weak balance, that is, 9 with
high frequency, 31 with mid-frequency and 46 with low frequency.
28
CHAPTER 4
TOPOLOGICAL PROCESSING OF
CHINESE CHARACTERS
The efficiency of visual identification for a matching pair increases when the items in
the pair are similar in some crucial perceptual features and decreases when the items in
the pair do not hold those features. Accordingly, if a prime is identical to a target in one
or more perceptual cues in a paradigm of priming effect, this primed stimulus should
produce a positive priming effect on the target (namely direct priming) and if a prime
contains no specified feature(s) of the target, there would be no positive priming effect
and a negative priming effect might even appear. In Experiment 1, we used
topologically equivalent Chinese character pairings to examine whether topological
properties affected the identification process in a visual-matching task. In Experiment 2,
we adopted a priming paradigm to test the same effect in Experiment 1 through a lexical
decision task.
One of the first results motivating the development of models of word recognition was
the frequency effect. Words that appear more often in written language are usually
recognised faster than words that occur rarely (e.g., Balota & Chumbley, 1984; Forster
& Chambers, 1973; Gao, Zhong & Zeng, 1995). The cause for this effect is assumed to
be the familiarity of a reader with the words. High frequency words have been
encountered more frequently and are thus processed more easily. The correspondence
29
of the number of times that a reader has been exposed to a word with counts from
written frequency norms, however, is far from perfect. Other variables including the
subjective familiarity with a word (Gemsbacher, 1984); Connine, Mullennix, Shernoff
& Yelens, 1990), the concreteness of a word (Bleassdale, 1987) or its contextual
availability (Schwanenflugel, 1991) are highly correlated with frequency and have been
shown to affect word recognition measures over and above frequency. In this study, we
incidentally tested the frequency effect of Chinese characters although it was not our
main purpose.
A visual matching task was considered susceptible to pre-lexical process and a lexical
decision task more sensitive to post-lexical decision and integration processes (cf.,
Balota, 1990, 1994). In the following experiments, I tested the hypotheses concerning
topology effects at both the pre-lexical and post-lexical stages, as well as frequency
effect.
30
4.1 EXPERIMENT 1
Experiment 1 aimed to determine whether topological property is crucial to identify the
Chinese characters in the primitive stage of processing, namely the topology effect. We
manipulated topological equivalence and frequency as independent variables while
controlling strokes and other features. Chen (1985) suggested that topological properties,
that is, closedness, separation and outside and inside relationships, are primitive to
perception. In Experiment 1, a very short presentation time (42.6 ms) plus an immediate
mask, which made the stimuli are extremely hard to be recognised, was given to avoid a
semantic or high cognitive process such as identifying a two-character pair.
4.1.1 Method
Participants. Twenty undergraduate students of the Fourth Military Medical University,
Xi'an, China, participated in the experiment. All were native Mandarin (Putonghua)
speakers and had normal or corrected-to-normal vision. Their ages ranged from 20 to 24
years and all were male.
Stimuli. On the principles of the topological equivalence and difference, i.e.,
holes/closure, e.g., 5 (shi2-stone)-fi (ji3-self), separation/connectivity, e.g., )L (er2-
child)--fc; (qil-seven), and inside-outside distinction, e.g., Wl (kun4-surround)-S (dail-
retard), 90 Chinese characters were chosen as stimuli, among which half were in high
frequency and another half in low frequency from the characters analysed in the
31
previous investigation (see Chapter 3 of this thesis). High frequency characters referred
to those with no fewer than 30 occurrences per million and low frequency characters
with fewer than 5 occurrences per million according to Modern Chinese frequency
dictionary (Wang and Chang, 1986). Three characters were in a group that matched each
other in strokes, frequency and other constructions, and varied only in topological
properties. For instance, (shi2-ten) (kou3 - mouth) and " I " (gongl
- work) were of a group in which and X were topologically equivalent (both were
connected) and • was topologically different from the other two because P included a
hole and the others comprised no hole (see Appendix A for all the stimuli). These three
characters were matched into 6 two-character pairs. That is, , " P - P " , " I - I " ,
" + - P " P - I " and among which the first three pairs (self-pairings) were
exactly paired with themselves, the fourth and fifth pairs were paired with topological
difference and the sixth was matched with topological equivalence. There were
altogether 15 groups in each frequency condition (high and low). That is, 30 pairs are
topologically different and 15 pairs topologically equivalent in each condition.
Therefore, totally 90 two-character pairs in total were used as the stimuli in the
experiment.
Design. It was a two-factor within-subjects design, in which reaction time and response
error were dependent variables and topological equivalence and frequency were
independent variables.
32
Procedure. A personal computer (Compaq PII 266) plus a screen (17 inches) with a
refresh rate of 14.2 ms was used to run this experiment. The Chinese characters were
presented tachistoscopically in white against a black background in a normal (Song) font
and each pair was shown once in the centre of the visual field. The task of participants
was to determine whether the form of the characters of a pair was exactly identical or
not, as quickly and correctly as possible. That is, with reference to the example of ,
"P", and "I", only the first three pairs, , "P-P", "I-I" , were identical and
the remaining pairs were different but no participants had been told these before and
after the experiments, they said they did not know this relationship. Each participant
was given 180 trials in total with 30 seconds rest after the first 90 trials.
The procedure was automatically monitored by STIM, a software developed by
Neuroscan to record reaction time and accuracy for each participant. Each pair was
arranged horizontally (left to right) with a distance of 5° between the centres of two
characters. Each character was of the same size and subtended 0.780 horizontally and
0.720 vertically. Before each trial, a small figure, ̂ was presented in the centre of the
visual field to check central fixation. The purpose of selecting this figure was to avoid a
topological equivalence between the fixation figure and the followed stimuli which
might produce an unexpected priming effect. The presentation time of the figure varied
from 800 ms to 1200 ms with a mean of 1000 ms and a standard deviation 100 ms to
inhibit a habituation. Then a stimulus pair was presented 42.6 ms both in the left and
right visual fields (same visual centre as the fixation), immediately replaced in the same
location by a mask which consisted of 60% white random dots. The pattern mask
33
occupied the same space as the stimuli and was presented for 28.4 ms. The fixation-
stimuli-mask pairings were presented in random order across the total 180 trials. Before
the testing, each participant was given clear instructions about the experiment (see
Appendix H) and then ample practice trials. Participants pressed the "1" button for
identical items and "4" button for different items with thumbs in a four-key board
developed by Neuroscan. To balance the habituation of hands, half of the participants
responded with left thumb for "1" and right thumb for "4", and the others reversed the
response pattern. Participants were tested individually in a dimly lit and quiet room, and
the whole experiment lasted approximately 10 minutes.
4.1.2 Results
One participant's data were eliminated because of high response errors in self-pairings
(86.67% for high frequency and 95.56% for low frequency respectively). Reactions
greater or less than 2.5 standard deviations were also excluded from the analysis and
only correct responses were accepted. The results were shown in Table 8. Topological
property (different or equivalent) is main variable in an analysis of variance (GLM-
repeated measures). The important results were that (a) topologically equivalent
Chinese characters with high frequency were more difficult to discriminate at a
tachistoscopical environment, whereas characters with low frequency showed no effects;
and (b) no frequency effects were found in both topologically equivalent and different
conditions.
34
The conclusions were supported by analyses of variance. A reliable topology effect for
high frequency characters was found for both reaction time (RT; F(l,18)=7.65,
MSE=\521,2A, p<0.05) and accuracy (F(l,18)=6.85, MSE=ll.ll, p<0.05), but there
were no significant topology effect for low frequency characters in both RT
(,F(1,18)=0.27, MSE=29S7.98, p>0.05), and accuracy (F(l,18)=0.05, MS!£=134.47,
p>0.05). No frequency effect was found in both topologically different (RT:
F(l,18)=0.85, MSE-S12J5, p>0.05; Accuracy: F(l,18)=1.85, MSE=106.92, /?>0.05)
and equivalent conditions (RT: F(l,18)=2.65, MS1£=4484.78, p>0.05; Accuracy:
F(l,18)=0.69, MS£=168.81,/»>0.05).
Table 8 Mean reaction time and accuracy for identifying topological equivalent or different characters (n=19)
High frequency Low frequency Different Different
D X , v 683.80+178.94 D r p / , 692.61 ±184.83 E T ( m S ) Equivalent R T ( m S > Equivalent
718.87 + 207.11 683.48 + 213.00
Different Different
A / 0 / N 74.91 ±17.23 A , 0 / . 70.35 ± 117.10 Accuracy (%) „ . < , Accuracy (%) ^ . J v y Equivalent y y Equivalent
67.72± 15.28 71.23 + 16.93 Note: the numbers in the table refer to mean plus or minus standard deviation.
Table 9 Mean reaction time and accuracy for frequency effects (n-19)
Equivalent Different High frequency High frequency
•Qrp / v 718.87±207.11 D T , v 683.80+178.94 RT (ms) t r ^ (ms) T -v Low frequency Low frequency
683.49 ±213.00 692.61 ±184.83
High frequency High frequency 67.22± 15.28 A , 0 / . • • 74.91 ±17.23
ccuracy( o) Low frequency ccuracy( o) Low frequency
71.23 ± 16.93 70.35± 17.10 Note: the numbers in the table refer to mean plus or minus standard deviation.
35
4.1.3 Discussion
The results of Experiment 1 revealed interesting effects in identifying topologically
equivalent or different Chinese character pairs.
First, only a topology effect for Chinese characters with high frequency was found;
identifying a topologically equivalent Chinese character pair with high frequency was
more difficult than identifying a topologically different pair. This result led to the
conclusion that topological properties did affect Chinese character processing, which
was consistent with the previous visual perception studies (e.g., Chen, 1982a, b, c, d;
Todd, Chen, Norman, 1998).
Second, this effect was not obtained for Chinese characters with low frequency. The
causes might be as follows, (a) Strokes of the Chinese characters with low frequency
(6.96 + 2.11) in the experiment were significantly greater than those of the characters
with high frequency (4.42 + 2.01), indicating the stimuli with low frequency had higher
complexity than the high frequency counterparts. As Chinese characters occupied same
spaces, it was reasonable to think that the higher in complexity, the smaller in size for
each component. This small size plus a tachistoscopical presentation would
undoubtedly put the Chinese characters with low frequency as a task with higher
difficulty. Particularly, when this difficulty reached some threshold, the stimuli would
be hard to recognise. In one word, the visibility for those Chinese characters with low
frequency damaged or diluted the effect. To match all the controlled variables,
36
unfortunately, it is almost impossible to collect so many low frequency characters which
have the same strokes as their high frequency counterparts, (b) Organisation in these
characters is more complicated than that in its high frequency counterparts as more
strokes constitute a character. The complicity of organisation confounded the factors
determining the response (see Chen, 1990). To avoid these two negative effects, it is
necessary to enlarge the size of Chinese characters and to simplify the organization of
the Chinese characters with low frequency in the future studies.
The results also failed to reveal a frequency effect for both topologically equivalent and
different Chinese characters. It might be caused by the tachistoscopical presentation
environment and less semantic involvement in the processing. As discussed by Ferstl &
d'Arcais (1999), frequency effect would be more likely to happen in a semantic process.
Unfortunately, the process involved in the identification intentionally diluted the
semantic involvements. Thus, it was reasonable to conclude it should not present a
frequency effect, although we should also be cautious before any further studies are
conducted.
37
4.2 EXPERIMENT 2
Experiment 2 was intended to replicate the topological effect found in Experiment 1
through other paradigms, which will extend its generality. The experiment was designed
through a typical priming paradigm in which a prime stimulus preceded with a target
stimulus. Priming refers to the fact that the time to respond to a word (the target) is
sometimes influenced when it is preceded by another usually morphologically,
phonologically or semantically related word (the prime). In this experiment the prime
and target were topologically related (cf. Roediger & McDermott, 1993). When a
topologically equivalent target was presented after a prime, it should induce a priming
effect whereas a topologically different target should not produce any effect or even
have a negative effect. This echoes the rationale in Experiment 1. In fact, Blaxton
(1989), Jacoby and Hayman (1987), and Madigan, McDowd and Murphy (1991)
reported a priming effect through matching typography. Roediger and McDermott
(1993) suggested in a lexical decision task that a prime and target occurring in close
temporal contiguity would be more probable to get a priming effect. In the present
experiment, there was no interval between the prime and the target to be sure of a salient
priming.
4.2.1 Method
Participants. Ten undergraduate students of the Fourth Military Medical University,
Xi'an, China, participated in Experiment 2. All were native Mandarin (Putonghua)
38
speakers and had normal or corrected-to-normal vision. Their ages ranged from 20 to 24
years and all were male.
Stimuli. The stimuli were the same as those used in Experiment 1 (see Appendix A).
Sixty pseudo-Chinese characters3 were selected from Appendix G.
Design^ It was a two-factor within-subjects design, in which reaction time and response
error were dependent variables and the topological property of the prime was the
independent variable in a lexical decision test.
Procedure. The computer in Experiment 1 with the same configuration was used to run
this experiment. The experimental paradigm was as follows. After a fixation check, a
prime would be presented followed by a target and then a mask. The prime would be
either topological equivalent to or different from the followed target or bear no
relationship to the target (Chinese character vs. pseudo-Chinese character). The stimuli
(Chinese characters or pseudo-characters) were presented tachistoscopically in white
against a black background in a normal (Song) font and each pair (fixation-prime-target-
mask) was shown once in the centre of the visual field. The task of participants was to
determine whether the second presented character was a real Chinese character or a
pseudo-Chinese character (lexical decision) as quickly and as correctly as possible.
Each participant was given 120 trials in total with 30 seconds rest after the first 60 trials.
Half trials were used to judge real Chinese characters and another half to judge pseudo
Chinese characters.
39
The procedure was automatically monitored by STIM to record reaction times and
accurate responses for each participant. Each character was of the same size and
subtended 0.78 0 horizontally and 0.72 0 vertically. Before each trial, a small figure was
presented in the centre of the visual field to check central fixation. The presentation
time of the figure varied from 800 ms to 1200 ms with a mean of 1000 ms and a
standard deviation 100 ms to avoid a habituation. Then a prime was presented for 42.6
ms, replaced with no break in the same location by a target (real or pseudo Chinese
character) for 85.2 ms, followed immediately by a mask that consisted of 60% white
random dots. The pattern mask occupied the same space as the stimuli and was
presented for 28.4 ms. The fixation-prime-target-mask pairings were presented in
random order across the total 120 trials. Before the task, each participant was given
clear instructions about the experiment (see Appendix H) and then ample practice trials.
Participants pressed the "1" button for a real Chinese character and the "4" button for a
pseudo Chinese character with thumbs. To balance the habituation of hands, half of the
participants responded with the left thumb for "1" and the right thumb for "4", and the
others reversed the response pattern. Participants were tested individually in a dimly lit
and quiet room, and the whole experiment lasted approximately 7 minutes.
4.2.2 Results
Reactions greater or less than 2.5 standard deviations were excluded from the analysis
and only correct responses were accepted. The results are shown in Table 10. There
40
were main priming effects of topological property for low frequency characters in both
RT (F(l,9)=7.01, MSE=36l 1.48, /?<0.05) and accuracy (F(l, 9)=8.68, MSE-S2.96,
p<0.05), but there were no significant effects for high frequency characters in both RT
(F(l,9)=0.08, MS£= 1882.99,/»0.05) and accuracy (F(l,9)=0.31, MSE=l 14.57, p>0.05).
No frequency effects were found in both different (RT: F(l,18)=0.85, MSE=872.75,
p>0.05; Accuracy: F(l,18)=1.85, MSE=106.92,p>0.05) and equivalent conditions (RT:
F(l,18)=2.65, MSE=4484.78,p>0.05; Accuracy: F(l,18)=0.69, MSE=l6&M,p>0.05).
Table 10 Mean reaction time and accuracy for identifying real Chinese characters or pseudo Chinese characters (n—10)
High frequency Low frequency
RT (ms)
Accuracy (%)
Equivalent 658.31 ±179.71
Different 652.93 + 135.72
Equivalent 84.00+12.26
Different 86.67 + 9.94
RT (ms)
Accuracy (%)
Equivalent 734.77 + 144.83
Different 805.92 + 178.09
Equivalent 70.67 + 13.41
Different 58.67± 15.96
Note: the numbers in the table refer to mean plus or minus standard deviation.
4.2.3 Discussion
A reliable priming effect was obtained both in reaction time and accuracy for low
frequency Chinese characters but not for high frequency ones. The results were just
reversed to those in Experiment 1. However, the results were consistent with other
studies in implicit memory (MacLeod, 1989; Scarborough, Cortese & Scarborough,
1977). In fact, it was understandable to conclude that high frequency of stimuli
41
damaged the priming effect because it was not easy to induce a data-driven or perceptual
process, comparing to low frequency.
Again, no frequency effect was found through a lexical decision task. The interpretation
for this result was similar to that in Experiment 1, that is, a process which involved data-
driven processing would not show a frequency effect easily(Ferstl & d'Arcais, 1999).
42
Chapter 5
PSYCHO-GEOMETRIC PROCESSING OF
CHINESE CHARACTERS
Experiments 1 and 2 investigated whether topological properties in a Chinese character
would affect the processing. The findings show a dissociation of topology effects in
which an effect was only found in Chinese characters with high frequency in a visual
matching paradigm and an effect was obtained in Chinese characters with low frequency
in a priming paradigm. In addition, no frequency effect was found in both visual
matching and priming tests. As analysed in Chapter 3, Chinese characters also have
symmetrical, closed, and/or linear properties. According to Ai (1948/1965), these
Chinese characters should be recognised more easily than others. Kao (2000) further
developed a psycho-geometric framework of reading and writing Chinese characters.
Based on the previous analysis (see Chapter 3), the following experiments were used to
test this hypothesis that a character having symmetrical, connected, closed and/or linear
properties is processed more quickly or more accurately than those having not sharing
these properties. In this experiment, I adopted a lexical decision paradigm. This
paradigm is considered to use less semantic processing and therefore is an appropriate
programme to test whether these properties are the main factors to influence the Chinese
character processing. In fact, a priming task is aimed to induce a data-driven
processing, so does the lexical decision task. In experiments 3a-d, I used the latter
43
because it is easier to design a lexical decision task and to control other unexpected
variables.
5.1 EXPERIMENT 3a
Experiment 3 a aimed to determine whether symmetrical Chinese characters are
identified more easily than asymmetrical ones (Ai, 1948; Kao, 2000 and Zeng, 1983).
Previous research in other fields has proved the superiority effect of symmetry, namely
the symmetry effect (see also Chapter 2 and 3). In the present study, we continued to
adopt a lexical decision task to test the hypothesis.
5.1.1 Method
Participants. Participants were the same as those in Experiment 1.
Stimuli. On the basis of the symmetrical property of a Chinese character, forty
symmetrical Chinese characters and forty asymmetrical Chinese characters matching in
strokes, linearity, connectivity, closure and structure in each frequency condition, and
sixty-five pseudo-Chinese characters were adopted as stimuli. Of the real Chinese
characters, half were high frequency characters and half were low frequency characters.
For example, (da4- big) and (feil-false) are symmetrical samples of
high frequency characters and " ¥ " (han4-rare) and " " (jingl-capital) are
asymmetrical samples of low frequency characters (see Appendix B). The pseudo
44
characters were created according to the Chinese character orthography (see Appendix
G). From Appendix B, it was understood that a small amount of low frequency Chinese
characters are of near symmetry such as E® (qu4- cricket) due to a difficulty to find so
much completely asymmetrical Chinese characters with low frequency.
Design. It was a two-factor within-subjects lexical decision task, in which reaction time
and response accuracy were dependent variables and symmetry of the presented Chinese
characters and frequency were independent variables.
Procedure. The computer in Experiment 1 with the same configurations was used to run
this experiment. The experimental paradigm was that after a fixation, a character would
be presented at the same location of the fixation, followed by a mask which was
comprised of 60% random white dots against a black background. The character would
be either a symmetrical, asymmetrical or pseudo Chinese character. The characters
were presented tachistoscopically in white against a black background in a normal (Song)
font and each pair was shown once in the centre of the visual field. The task of the
participants was to determine whether the presented character was a real Chinese
character or a pseudo-Chinese character as quickly and as correctly as possible. Each
participant was given 145 trials in total with 30 seconds rest after the first 80 trials.
Fifty-five percent trials were used to judge real Chinese characters and the remaining
45% to identify pseudo Chinese characters, but no participants were told of this
arrangement before and after the test.
45
The procedure was automatically monitored by STIM to record reaction times and
accurate responses for each participant. Each character was of the same size and
subtended 0.78 0 horizontally and 0.72 0 vertically. Before each trial, the same figure
used in Experiment 1 was presented in the centre of the visual field to check central
fixation. The presentation time of the figure varied from 800 ms to 1200 ms with a
mean of 1000 ms and a standard deviation 100 ms to avoid a habituation. Then a
character was presented for 85.2 ms, immediately replaced in the same location by a
mask for 28.4 ms. The fixation-target-mask pairings were presented in random order
across the total 145 trials. Before the task, each participant was given a clear instruction
of the experiment (see Appendix H) and then ample practice trials. Participants pressed
the "1" button for a real Chinese character and the "4" button for a pseudo character
with thumbs. To balance the habituation of hands, half of the participants responded
with the left thumb for "1" and the right thumb for "4", and others reversed the response
pattern. Participants were tested individually in a dimly lit and quiet room, and the
whole experiment lasted approximately 8 minutes.
5.1.2 Results
Two participants' data were eliminated because of high response errors in low frequency
characters (80% and 60% for symmetric characters, and 85% and 85% for asymmetric
characters, respectively). Reactions greater or less than 2.5 standard deviations were
excluded from the analysis and only correct responses were accepted.
46
The results were shown in Table 11. Symmetric property (symmetry or asymmetry) of a
Chinese character and frequency were main variables in an analysis of variance (GLM-
repeated measures). There was a significant symmetry effect for low frequency
characters in both RT (F( 1,17)= 10.22, MS£=982.71, pO.Ol) and accuracy
(F(l,17)=5.47, MSE-IA6.9Q, p<0.05), but there were no significant effects for high
frequency characters in both RT (F(l,17)=3.94, MSF=446.72, ^>0.05), and accuracy
(F( 1,17)=0.68, MSE=50.20, p>0.05).
There was a significant frequency effect (Table 12) in both symmetric (RT:
F(l,17)=53.40, MS!£=1412.22, /K0.001; Accuracy: F(l,17)=37.99, MSE=82.07,
p<0.001) and asymmetric conditions (RT: F(l,17)=56.78, MSE=3059.54, ^<0.001;
Accuracy: F(l,17)=54.54, MSF^MS.SS^O.OOl).
Table 11 Mean reaction time and accuracy for identifying real Chinese characters or pseudo characters (n=18)
High frequency Low frequency Symmetric Symmetric
P T r m > 574.13 + 128.82 - 665.67+164.87 R1 (ms) A RT (ms)
Asymmetnc Asymmetnc 560.15 + 127.58 699.08 ± 186.87
Symmetric Symmetric . , 0 / , 87.22 + 10.03 . 68.61 ±12.10
Accuracy (%) . ^ . Accuracy (%) . Asymmetnc Asymmetnc
89.17 + 9.89 59.17± 15.74 Note: the numbers in the table refer to mean plus or minus standard deviation.
Table 12 Mean reaction time and accuracy for frequency effect (n-18)
Symmetric Asymmetric High frequency High frequency
, 574.13±127.87 D T , , 560.15± 127.59 RT (ms) T xl RT (ms) T „ v ' Low frequency Low frequency
665.67± 164.87 699.08 ± 186.87
47
High frequency High frequency
/ 0 / , 87.22± 10.03 . , 0 / . 89.17 + 9.89 Accuracy (%) T ~ Accuracy (%) T ~ J Low frequency J y Low frequency
68.61 + 12.10 59.17± 15.74 Note: the numbers in the table refer to mean plus or minus standard deviation.
5.2 EXPERIMENT 3b
Experiment 3b aimed to test whether linear Chinese characters, which had been
operationally defined in Chapter 3, were recognised better than non-linear ones. Ai
(1948/1965) and Kao (2000) had suggested a superiority effect of linearity, namely the
linearity effect (see also Chapter 2 and 3 of this dissertation). In this experiment, we
continued to adopt a lexical decision task, as used in Experiment 3 a, to test the above
hypothesis.
5.2.1 Method
Participants. Participants in the experiment were the same as those in Experiment 1.
Stimuli. On the basis of the linear property of a Chinese character, 22 linear Chinese
characters and 22 non-linear Chinese characters matching in strokes, symmetry, closure,
connectivity and structure in each frequency condition, and 36 pseudo characters were
selected as stimuli. Of the real Chinese characters, half were high frequency characters
and half were low frequency characters. A linear character referred to a character
consisting of more than 75% of straight lines (horizontal or vertical such as "IE"
48
(zheng4-correct) and (shengl-alive)) and a non-linear character meant it comprised
over 75% of curves including dot and oblique line such as (xiangl - home) and
"ffi" (lu4 - kill). All the selected Chinese characters were listed in Appendix C. The
pseudo characters were selected from Appendix G.
Design. It was a two-factor within-subjects lexical decision task, in which reaction time
and response accuracy were dependent variables and linearity of the presented Chinese
characters and frequency were independent variables.
Procedure. The whole procedure, including the fixation, stimuli and mask presentation
time, size and place, and task, was the same as that in Experiment 3 a, except for the
stimuli and trials. Each participant was given 80 trials in total with a 30-second rest
after the first 40 trials. Fifty-five percent trials were used to judge real Chinese
characters and the remaining 45% to identify pseudo Chinese characters, but no
participants were told of this arrangement before and after the test.
The procedure was automatically monitored by STIM to record reaction times and
accurate responses for each participant. Before the task, each participant was given
clear instructions about the experiment (see Appendix H) and then ample practice trials.
Participants pressed the "1" button for a real Chinese character and the "4" button for a
pseudo character with thumbs. To balance the habituation of hands, half of the
participants responded with the left thumb for "1" and the right thumb for "4", and
49
others reversed the response pattern. Participants were tested individually in a dimly lit
and quiet room, and the whole experiment lasted approximately 6 minutes.
5.2.2 Results
Three participants' data were eliminated because of high response errors in low
frequency non-linear characters (90.91% for all three participants). Reactions greater or
less than 2.5 standard deviations were excluded from the analysis and only correct
responses were accepted.
The results are shown in Table 13. The linear property (linear or non-linear) of a
Chinese character was of main variable in an analysis of variance (GLM-repeated
measures). There was no significant linearity effect for both high (RT: JP(1,16)=0.18,
MSE= 1570.56, p>0.05, and accuracy: F(l,16)=0.41, MSE=95.11, p>0.05) and low
frequency Chinese characters (RT: F(l,16)=1.33, MSE=\ 1601.27,/?>0.05, and accuracy:
F( 1,16)=2.95, MSE= 161.34, p>0.05).
There was also a significant frequency effect (Table 14) in both linear (RT:
F(l,16)=15.85, MSE=8364.09, ^<0.001; Accuracy: F(l,16)=47.80, MS£=221.50,
p<0.001) and non-linear conditions (RT: F(l,17)=23.33, JWS£'=10938.88, £><0.001;
Accuracy: F(l,17)=135.69, MSE=l26A0,p<0.00l).
Table 13 Mean reaction time and accuracy for identifying real Chinese characters or pseudo characters (n=17)
50
High frequency Low frequency
RT (ms)
Linear 560.98±99.67
Nonlinear 555.29± 130.09
RT (ms)
Linear 685.86 ± 207.31
Nonlinear 728.51 ±226.78
Accuracy (%)
Linear 86.10± 14.77
Nonlinear 88.24± 11.48
Accuracy (%)
Linear 50.80±21.58
Nonlinear 43.22± 14.56
Note: the numbers in the table refer to mean plus or minus standard deviation.
Table 14 Mean reaction time and accuracy for frequency effect (nz -18)
Linear Nonlinear
RT (ms)
High frequency 560,98±99.67
Low frequency 685.86 ± 207.31
RT (ms)
High frequency 555.25 ±130.09
Low frequency 728.51 ±226.78
Accuracy (%)
High frequency 86.10 ± 14.77
Low frequency 50.80 ± 21.58
Accuracy (%)
High frequency 88.24 ± 11.48
Low frequency 43.32 ±14.56
Low frequency
Accuracy (%) Nonlinear
88.24+11.48
RT (ms)
Accuracy (%)
Linear 685.86 + 207.31
Nonlinear 728.51 ±226.78
Linear 50.80+21.58
Nonlinear 43.22+14.56
Note: the numbers in the table refer to mean plus or minus standard deviation.
Table 14 Mean reaction time and accuracy for frequency effect (n-18)
Linear Nonlinear
RT (ms)
Accuracy (%)
High frequency 560,98±99.67
Low frequency 685.86 + 207.31
High frequency 86.10+14.77
Low frequency 50.80 + 21.58
RT (ms)
Accuracy (%)
High frequency 555.25 ±130.09
Low frequency 728.51 ±226.78
High frequency 88.24 ± 11.48
Low frequency 43.32 ±14.56
Note: the numbers in the table refer to mean plus or minus standard deviation.
51
5.3 EXPERIMENT 3c
Experiment 3c aimed to test whether the closed Chinese characters were recognised
faster or more accurately than opened or half-closed ones. Kao (2000) suggested a
superiority effect of closedness, say the closure effect (see Chapter 2 and 3). In this
experiment, we continued to adopt a lexical decision task, as used in Experiment 3a, to
test the hypothesis.
5.3.1 Method
Participants. Participants in the experiment were the same as those in Experiment 1.
Stimuli. On the basis of closure property of a Chinese character, 22 completely closed,
22 completely open, 22 half-open Chinese characters, matching in strokes, linearity,
connectivity, symmetry and structure in each frequency condition, and 54 pseudo
characters were selected as stimuli. Of the Chinese characters, half were high frequency
characters and half were low frequency characters in all three conditions. In the
experiment, a completely closed character was embedded in a closed frame, e.g., "15"
(nation) and " 0 " (prisoner), a completely open character was composed of no bound
frame, e.g., "iS" (state) and "jr"(celery), and a half-open character consisted of an
almost closed bound frame, e.g., "fE3" (depressed) and "f*|" (a Chinese surname). All
52
the selected Chinese characters were listed in Appendix D. The pseudo characters were
created according to the Chinese character orthography (see Appendix G).
Design. It was a two-factor within-subjects lexical decision task, in which reaction time
and accurate response were dependent variables and closedness of the presented Chinese
characters and frequency were independent variables.
Procedure. The whole procedure including the fixation, stimuli and mask presentation
time, size and place, and task was the same as that in Experiment 3a, except for the
stimuli and trials. Each participant was given 120 trials in total with 30 seconds rest
after every 60 trials. Fifty-five percent trials were used to judge real Chinese characters
and the remaining 45% to identify pseudo Chinese characters, but no participants were
told of this arrangement before and after the test.
The procedure was automatically monitored by STIM to record reaction times and
accurate responses for each participant. Before the task, each participant was given
clear instructions about the experiment (see Appendix H) and then ample practice trials.
Participants pressed the "1" button for a real Chinese character and the "4" button for a
pseudo character with thumbs. To balance the habituation of hands, half of the
participants responded with the left thumb for "1" and the right thumb for "4", and
others reversed the response pattern. Participants were tested individually in a dimly lit
room, and the whole experiment lasted approximately 6 minutes. The reaction times
and accuracy rates were recorded for each participant.
53
5.3.2 Results
Three participants' data were eliminated because of high response errors of completely
open characters for low frequency (over 90% for all three participants). Reactions
greater or less than 2.5 standard deviations were excluded from the analysis and only
correct responses were accepted.
The results were shown in Table 15. Closure property (completely closed, completely
open and half-closed) of a Chinese character was the main variable in an analysis of
variance (GLM-repeated measures). There was a significant effect of closure property
for low frequency characters (RT: F(2,32)=1.36, MSFK3885.04, /?>0.05, and accuracy:
F(2,32)=4.75, MSE=2S2.77, p<0.05) but there was no reliable effect for high frequency
characters (RT: F(2,32)=0.72, MS£=3724.52, p>0.05, and accuracy: F(2,32)=3.18,
MSE=\ 10.60, p=0.06). Post Hoc Test (LSD) showed a significant difference between
completely closed and half-closed characters (Diff=\7.65, SE=6.22, p<0.01).
There was a significant frequency effect (Table 16) in completely closed (RT:
F(l,16)=3.48, MSE=5722.07, p=0.08; Accuracy: F(l,16)=l 1.73, MSE=140.07,/K0.01),
and completely open (RT: F( 1,16)= 18.02, MSE=2642.18, p<0.001; Accuracy:
F(l,16)=51.31, MS£=148.58, p<0.001), and half-closed (RT: F(l,16)=13.87,
MSE=5775.09,p<0.0\; Accuracy: F(l,16)=53.52, MS£=203.88,p<0.001) conditions.
Table 15
54
Mean reaction time and accuracy for identifying real Chinese characters or pseudo characters (n~17)
High frequency Low frequency
RT (ms)
Completely closed 559.62 ± 136.10
Completely open 535.14+114.36
Half-closed 542.33 + 137.69
RT (ms)
Completely closed 608.01 ±170.83
Completely open 609.98± 161.16
Half-closed 639.42± 191.75
Accuracy (%)
Completely closed 79.68 ±13.84
Completely open 88.77 ± 11.82
Half-closed 83.96± 15.92
Accuracy (%)
Completely closed 65.78± 16.86
Completely open 58.82± 19.32
Half-closed 48.13 ± 18-11
Note: the numbers in the table refer to mean plus or minus standard deviation.
Table 16 Mean reaction time and accuracy for frequency effect (n=17)
Completely Closed Completely Opened Half-Closed
RT(ms)
High frequency
5 5 9 . 6 2 ± 136.10 Low frequency
608.01 ± 1 7 0 . 8 3
RT(ms)
High frequency
535 .14± 114.36 Low frequency
609.98 ± 161.16
RT(ms)
High frequency
542.33 ±137 .69 Low frequency
639.42± 191.75
Accuracy (%)
High frequency
7 9 . 6 8 ± 13.84 Low frequency
6 5 . 7 8 ± 16.86
Accuracy (%)
High frequency
88 .77± 11.82 Low frequency
58 .82± 19.32
Accuracy (%)
High frequency 83 .96± 15.92
Low frequency 48.13 ±18 .11
Note: the numbers in the table refer to mean plus or minus standard deviation.
5.4 EXPERIMENT 3d
Experiment 3d aimed to examine whether Chinese characters with left-to-right form
were recognised faster or more accurately than those with top-to-down form. As
discussed before, vision is more accustomed to search from the left side to the right ride
than in other directions. In this experiment, I continued to adopt a lexical decision task,
as used in Experiment 3 a, to test the hypothesis that this visual habit is a superiority for
judging a character, namely the structure effect.
55
5.4.1 Method
Participants. Participants in the experiment were the same as those in Experiment 1.
Stimuli. On the basis of the structure property of a Chinese character, 40 horizontally
arranged (left-to-right structure) Chinese characters and 40 vertically arranged (top-to-
down structure) Chinese characters, matching in strokes, symmetry, closure, linearity
and connectivity in each frequency condition, and 60 pseudo characters were selected as
stimuli. Of the Chinese characters, half were high frequency characters and half were
low frequency characters across the two conditions. Horizontally arranged Chinese
characters were defined as those characters formed horizontally with their components,
e.g., "5tr" (lu4 - road) and "itr" (an4 - understand), and vertically arranged Chinese
characters as those characters formed vertically with their components, e.g.,
(shengl - sound) and "tP ' (zil - consult). All the selected Chinese characters were
listed in Appendix E. The pseudo characters were created according to the Chinese
character orthography (see Appendix G).
Design. It was a two-way within-subjects lexical decision task, in which reaction time
and response error were dependent variables and the structure and frequency of the
presented Chinese characters were independent variables.
Procedure. The whole procedure including the fixation, stimuli and mask presentation
time, size and location, and tasks, was the same as that in Experiment 3a except for the
56
stimuli and trials. Each participant was given 140 trials in total with 30 seconds rest
after every 70 trials. Fifty-five percent trials were used to judge real Chinese characters
and the remaining 45% to identify pseudo Chinese characters, but no participants were
told of this arrangement before and after the test.
The procedure was automatically monitored by STIM to record reaction times and
accurate responses for each participant. Before the task, each participant was given
clear instructions about the experiment (see Appendix H) and then ample practice trials.
Participants pressed the "1" button for a real Chinese character and the "4" button for a
pseudo character with thumbs. To balance the habituation of hands, half of the
participants responded with the left thumb for "1" and the right thumb for "4", and
others reversed the response pattern. Participants were tested individually in a dimly lit
room, and the whole experiment lasted approximately 6 minutes.
5.4.2 Results
Two participants' data were eliminated because of high response errors of horizontally
arranged characters (left-to-right) for low frequency (one reached 85% and another
95%). Reactions greater or less than 2.5 standard deviations were excluded from the
analysis and only correct responses were accepted.
The results were shown in Tablel7. Form and frequency of a Chinese character were
main variables in an analysis of variance (GLM-repeated measures). There was a
57
reliable structure effect for low frequency characters (RT: F(l,17)=5.53, MSE=2251.04,
p<0.05, and accuracy: F(l,17)=3.333, MS£=151.84, p=0.Q9) but there was no
significant effect for high frequency characters (RT: F(l,17)=3.34, MSE=l 121.26,
p= 0.09, and accuracy: F(l,17)=1.39, MSE=97.88, p>0.05). The finding that low
frequency Chinese characters with top-to-down structure are determined faster
contradicted the prediction.
Table 17 Mean reaction time and accuracy for identifying real Chinese characters or pseudo characters (n~18)
High frequency Low frequency
RT (ms)
Horizontally arranged 600.99 ±147.43
Vertically arranged 580.59± 133.58
RT (ms)
Horizontally arranged 716.38 ± 205.92
Vertically arranged 679.18± 182.88
Accuracy (%)
Horizontally arranged 80.56 ±16.26
V erti cally arranged 84.44 ±14.54
Accuracy (%)
Horizontally arranged 46.67 ± 19.48
Vertically arranged 54.17± 15.55
Note: the numbers in the table refer to mean plus or minus standard deviation.
Table 18 Mean reaction time and accuracy for frequency effect (n~18)
Horizontal arranged Vertically arranged
RT (ms)
High frequency 600.99 ±147.43
Low frequency 716.38 ± 205.92
RT (ms)
High frequency 580.59± 133.58
Low frequency 679.18± 182.88
Accuracy (%)
High frequency 80.56± 16.26
Low frequency 46.67 ± 19.48
Accuracy (%)
High frequency 84.44± 14.54
Low frequency 54.17± 15.55
Note: the numbers in the table refer to mean plus or minus standard deviation.
There was a significant frequency effect (Table 18) both in horizontally arranged
characters (RT: F(l,17)=29.90, MSF=4008.35, /K0.001; Accuracy: F(l,17)=52.24,
58
MSE= 197.88, /?<0.001), and vertically arranged characters (RT: F(l,17)=32.15,
MS!E=2721.14, p<0.001; Accuracy: F(l,17)=38.83, M££=212.46,p<0.001).
5.5 Discussion
The four experiments aimed to test a psycho-geometric framework for reading Chinese
characters. The important results of these experiments were that (a) almost all positive
psycho-geometric effects appeared in Chinese characters with low frequency except for
linear Chinese characters; (b) Chinese characters with top-to-down structure were
processed more easily than those with left-to-right structure which did not support the
general prediction of vision being from left-to-right; (c) no significant linearity effect
was found for the linear Chinese characters, and (d) there was a significant frequency
effect obtained in all the experiments.
The failure to observe psycho-geometric effects in Chinese characters with high
frequency might be caused by the following facts. Firstly, the frequency effect may
dilute the psycho-geometric effect in Chinese characters with high frequency. Secondly,
it is known that the processing of a character with high frequency is determined heavily
by its potential activity, automaticity, and level of processing. Seidenberg (1983)
pointed out that processing a word with high frequency is a top-down/holistic process
and processing a word with low frequency is most probably a bottom-up/analytic
process. The difference between the two processes would result in a difference in using
other visual cues including the above psycho-geometric cues. Thirdly, the process of
59
judging a Chinese character with high frequency is highly automatic and uses less effort.
Thus it is not difficult to conclude that other physical cues are less important for this
process. The story for characters with low frequency, however, is different. As it is
mainly a bottom-up process which is classified as a highly data-driven/perceptual
process (Roediger & McDermott, 1993), the processing takes advantage of any cues
available. A perceptual process highly depends on the perceptual cues of the stimuli.
Apparently, the role of those psycho-geometric cues manifest and thus a psycho-
geometric effect takes place. Finally, it is expected that if the perceptual environment is
changed, e.g., a faster presentation time, a strong mask, a distracted filler task and/or a
fast-search task other than lexical decision test, are adopted, it may produce a significant
effect or even reverse the effect.
It is well known that bilateral symmetry is often considered the most salient
organizational aspect of a stimulus in vision (see, e.g., Locher & Nodine, 1973; Mach,
1897; Palmer, 1989; Rock, 1983; Royer, 1981). Attneave (1957) and Day (1968) found
symmetrical shapes are judged less complex than asymmetrical shapes. That is,
symmetrical shapes, due to its redundant features, contain less information content than
do asymmetrical counterparts equated for complexity. Thomas (1963), and Noton and
Stark (1971) found subjects exhibited some preference for one side or the other a
symmetrical display, that is, subjects developed a one-sided visual scanning strategy for
symmetrical shapes. Locher and Nodine (1973) proposed that subjects use an early
organizing code that permits the generation of a feature code on the basis of partial
information. The advantage of symmetrical forms is due to the reduction in information
60
from redundant features. Royer (1981) further suggested the redundancy of features in
bilaterally symmetrical shapes makes the judging process faster.
In the present experiments, Chinese characters are just a kind of geometrical shape and
thus it should find a symmetry effect in which symmetrical Chinese characters are
processed more quickly when the perceptual condition is preferable.
Holes are a typical type of topological properties (See Casati and Varzi, 1995, and Chen,
1990 for the extensive and detailed descriptions). Chen and Zhou (1997) found subjects
perceived illusory hollow figures in which the conjoined holes underwent geometrical
transformations, indicating that the holes were detected as abstract topological entities
available at an early stage. Kao (2000) proposed that holes in Chinese characters could
facilitate processing. One of the experiments aimed to test this hypothesis which was
supported by the results showed that a completely closed Chinese character was decided
faster than a half-closed counterpart (closure effect).
Linearity (see Kao, 2000) was originally predicted as a positive cue forjudging Chinese
characters (linearity effect). The results were not supportive of this hypothesis. It
indicates that linearity is not a primitive and important feature for deciding Chinese
characters in a lexical decision task. The investigation in this Chapter showed a lower
popularity of both high and low linearity across the all Chinese characters although lines
appear in most Chinese characters. This investigation may imply a less importance of
linearity. In fact, to create a character using more linear lines would only increase the
61
strokes or complexity because when keeping the strokes constant, a character mainly
consisting of a single component would inevitably decrease the possibility of
combination. However, we should be cautious to draw this conclusion before other
tasks, stimuli, and presentation environment are tested.
There is no left-to-right structure effect but a reversed effect, i.e., a significant top-to-
down structure effect found. It is an interesting result although it contradicted the
prediction. The underlying causes are still not clear. One of the probable causes is that
the top-to-down structure (form) shows a clear appearance that permits the whole
character to be viewed at the same time, say, a holistic strategy, and although the left-to-
right form fits the visual habit, this construction leads to serial processing and is easy to
block a holistic/parallel processing which is believed to act more quickly.
It is also probable that Chinese was read top to down in the older texts or even in some
texts now. And this reading habit may have had a long-term impact in the later reading
of Chinese people. Chinese is written horizontally only after the invention of typing and
the Chinese mainland promoted a simplification movement in 1950's (Wang, 1973;
Zhou, 1998).
62
CHAPTER 6
TOPOLOGICAL AND SYMMETRICAL
PROCESSING OF CHINESE CHARACTERS:
AN EVENT RELATED POTENTIAL STUDY
6.1 INTRODUCTION
The above behavioural studies have proved that topological and psycho-geometric
properties facilitate Chinese character processing through a visual matching task,
priming task and lexical decision task. In the following experiments, the most salient
properties, topological properties and symmetry, were extracted to apply to an ERP
study.
Electroencephalography (EEG) is a technique in which the electrical activity of the brain
is measured and how this changes in association with stimuli, responses or mental states
such as attention is observed. EEG has very high temporal resolution which is in the
order of a few milliseconds although the spatial resolution is relatively low, i.e., it is
difficult to precisely locate where in the brain the signals are coming from. Usually the
electrical activity is recorded from electrodes attached to the scalp. ERP, a kind of
evoked potential, concerns the delineation of brain activity associated with specific
63
cognitive processes and the measurement precisely when and where this activity takes
place.
ERP components elicited by visual discrimination stimuli include the PI (the first
positive waveform among ERPs), N1 (the first negative waveform among ERPs), P2
(the second positive waveform), N2 (the second negative waveform), and P3 (the third
positive waveform) components. ERP components are labelled by the polarity (negative
or positive) and temporal order of appearance in the ERP. The peak latency ranges from
for the visual ERP components elicited during discrimination tasks are typically in the
following time ranges: PI (80-145 ms), N1 (100-200 ms), P2 (200-300 ms), N2 (200-
350 ms) and P3 (280-600 ms). (See O'Donnell, Swearer, Smith et al, 1997).
This chapter reports on 2 experiments that aimed to further test the effects obtained in
topological properties and symmetry in the behavioural experiments 1, 2, and 3a-d, and
tried to locate the cortex activation of the those effects and explore the time courses of
processing a topological property in a character pair and judging a character having a
symmetrical property.
6.2 EXPERIMENT 4
6.2.1 Method
Participants. Forty tertiary students (all male), aged 19-21, were evaluated. All
participants were right handed and had normal or corrected-to-normal vision at the
64
Fourth Military Medical University, with no history of neurological injury, psychoactive
drug or alcohol abuse and psychiatric diagnosis. Before the experiment, participants
were asked to clear their hair and to be free from any neural exhilarant for 3 hours and
none of these individuals had taken part in previous experiments. Informed consents
were obtained from all participants.
Design. This was a two-way within-subjects design, in which reaction time, response
error and ERPs (amplitude and latency) were dependent variables and topological
equivalence was the independent variables. In order to meet the standard design of ERP
experiments that required no fewer than 20 trials for each condition, the character
frequency factor was not considered in this experiment.
Stimuli and tasks. The stimuli and tasks were the same as in Experiment 1 (see
Appendix A). The same procedure as in Experiment 1 was adopted, except that the
inter-trial interval duration varied slightly from trial to trial in order to avoid a
habituation (average ISI 1.30 sec, ranging from 1.25 sec to 1.35 sec) and an EEG
recording was conducted simultaneously. Before the tasks, each participant was given
clear instructions about the experiment (see Appendix H) and then ample practice trials.
Participants were individually tested in a quiet, dimly lit and electrically shielded room.
EEG recordings. EEG activity was recorded continuously through 30 AgCl electrodes
attached to recording sites of the 32-channel Neuroscan system (see Appendix I for
electrode map across the scalp). Seven electrodes were placed at frontal (Fpl, Fp2, F7,
65
F3, Fz, F4, F8), six at left temporal (Ft7, Fc3, T7, C3, Tp7, Cp3), three at central (Fez,
Cz, Cpz), six at right temporal (Fc4, Ft8, C4, T8, Cp4, Tp8) and eight at parietal-
occipital (P7, P3, Pz, P4, P8, 01, 02, Oz). Behavioural responses were also recorded by
the Neuroscan system. Trials with artifacts larger than 0.5 mV were excluded from
further analysis. Horizontal and vertical EOG artifacts were corrected according to the
method developed by Elbert, Lutzenberger, Rockstroh, and Birbaumer (1985).
Impedances were maintained below 5 kilohm. The EEG was amplified and analog
filtered with 0.1 Hz to 40 Hz bandpass filters and a 60 HZ notch filter.
Data analysis. Some participants' data were eliminated due to excessive EEG artifacts
and response errors (errors over 60% in topologically different and equivalent, and self-
matching pairs). Since EEG recoding needed at least 20 trials for a condition, we did
not consider the character frequency factor in this experiment. Peak amplitude and
latency values were used to measure components in this study. Both peak amplitude
and latency values were obtained for each electrode site at the most positive or negative
voltage within the time window of interest using an automated algorithm. All amplitude
measurements were taken relative to average baseline voltage in the 100 ms interval
prior to stimulus onset. Only a clearly early positive component (P1') and a subsequent
negative component (N1'), both occurring earlier than PI and Nl) were measured at the
most positive voltage. The wavelength of PI' ranges from 40 to 80 milliseconds and
Nl ' from 80 to 160 milliseconds from all the pairs.
6.2.2 Results
66
6.2.2.1 Behavioural data
The behavioural results are shown in Table 19. Topological property (different or
equivalent) is main variable in an analysis of variance (GLM-repeated measures). There
were main effects of topological property for selected Chinese characters in both
reaction time (RT), F(l,37)=6.25, MS*£=683.81, p<0.05, and accuracy, F(l,37)=9.00,
MiSEK31.46,/K0.01.
Table 19 Mean reaction time and accuracy for identifying topological equivalent or different characters (n=38)
Different Equivalent RT (ms) 610.24± 147.55 625.24+161.53 Accuracy (%) 82.25+14.49 79.39+14.92
6.2.2.2 ERP data
Only significant EEG data are shown in Tables 20-21 (other EEG data are listed in
Appendix J1 and J2). The times course of occurrence of the P and N components (see
Appendix J1 and J2) indicated that the processes begin at the parietal-occipital areas,
through temporal areas to anterior frontal lobes, again to temporal lobes and finally goes
back to the parietal-occipital lobes. It can primarily suggest that the sites of TP8 in the
right temporal lobe and P3 in the parietal-occipital area (the visual cortex) were
demonstrated to associate with the topological processing. And F8 and Fp2 in the
frontal lobe, T7 in the left temporal lobe, Fc4 in the right temporal lobe, and Oz and P8
67
in the Parietal-Occipital Area were probably involved in processing topological
properties. So, the probable mechanism of processing topological properties is that the
visual cortex detects a pair of topological properties and then the information is sent to
temporal lobes foi furthei processing which is a type of language processing, under the
regulation of anterior frontal lobe.
The early ERP components (P: 40-80 ms; N: 80-160 ms) in processing topological
properties in Chinese characters showed that the process is pre-attentive.
Table 20 Mean latency and amplitude of the positive waveform (40-80 ms) across the scalp (n=37)
Electrode Latency Amplitude Spot Diff Ecju t p Diff Egu t p Anterior Frontal Lobe
F8 6 7 . 4 0 + 1 3 . 4 8 6 2 . 4 9 ± 15.20 1.75 0.09
Left Temporal Lobe
T7 60 .65+12 .61 64.81 + 12.94 1.85 0.07
Right Temporal Lobe
Fc4 5 5 . 0 8 + 1 1 . 7 7 60.22+14.51 1.94 0.06
Tp8 5 7 . 8 9 + 1 2 . 2 3 63.19 + 13.21 2.30 0.03
Parietal-Occipital Area
P3 1 .09+3.02 2 .06+3 .55 2.14 0.04
Oz 0 .17+1 .62 0 .54+1.91 1-76 0.09
Note: Diff-difference; Equ-equivalence, and one participant's EEG data was further excluded due to a bad waveform.
Table 21 Mean latency and amplitude of the negative waveform (80-160 ms) across the scalp (n=37)
Electrode Latency Amplitude Spot Diff Equ t p Diff Egu t p Anterior Frontal Lobe Fp2 9 5 . 8 9 + 1 6 . 3 0 101.78+19.34 1.84 0.07
Parietal Occipital Area
P8 -2 .73 + 2.88 -3 .17+2 .76 1-80 0.08
68
6.2.3 Discussion
The behavioural results are consistent with those in Experiment 1. The EEG results
only showed a positive wave (P component) and a negative wave (N component). Very
interestingly, the P (40-80 ms) and N (80-160) components showed here take place
earlier than PI (80-145 ms) and Nl (100-200 ms) reported by other studies (see
O'Donnell, Swearer, Smith et al, 1997). These two early components proved that
topological processing occurs at the very early stage. This result is consistent with
Chen's behavioural studies that a primitive and general function of the visual system is
the perception of global topological properties. It is known that the form of the early
components of EEG is almost certainly determined by the nature of the eliciting
stimulus (e.g., geometricity). Later components depend on the specific information
processing operations recruited by the stimuli (see Frith, 1997). In particular, the Nl, a
negative deflection occurring approximately 100 ms after the eliciting stimulus, is
generally regarded as an exogenous component of ERP modulated by stimulus
parameters and attention (Hillyard, Mangun, Wordorff, & Luck, 1995). As the visual
matching task used in the experiments involves less semantic processing, it is possible
that no further positive and negative components are produced.
Although ERP can not precisely map the activation of the processing due to a poor
spatial resolution in this condition, say, little is known about the relationship between
the signal recorded at the scalp and the activity in individual neurons or groups that give
69
rise to this signal, the results provide a clear flow-chart of the activation from the
origination to the end (probably some parts in the inferior temporal lobe and the superior
occipital area play an important role) and they also clearly show an early occurrence of
this process which is consistent with other behavioural studies in visual perception
(Chen 1982a, 1989,; Todd, Chen & Norman, 1998).
70
6.3 EXPERIMENTS
Since detecting symmetry is considered a primitive function of perception, it is expected
that the early ERP components, especially the exogenous components, the Nl and P2,
will play an important role, as those in processing topological properties. N2 has also
been suggested to reflect a central orienting response (Ford, Roth, & Kopell, 1976;
Squires, Squires, & Hillyard, 1975) and is thought to reflect a decision process related to
sensory discrimination of attended stimuli (Ritter, Simon, Vaughan, & Friedman, 1979).
A visual detection task with 80% standard and 20% target is intentionally used to
produce P3 component which has been related to several aspects of the processing of
task relevant stimuli (See review in Verleger, 1988). P3 is sensitive both to the
subjective frequency of a stimulus (Ritter, Vaughan, & Costa, 1968) and to the
relevance of a stimulus to the current task (Courchesne, Hillyard, & Galambos, 1975;
Donchin, 1979). The P3 has been proposed as an index of multiple cognitive processes,
including context updating, memory consolidation, orienting, processing termination
and decision making (Donchin & Coles, 1988; Johnson, 1988; Verleger, 1988).
Although enhancement of ERP late components (e.g., N2 and P3) to stimuli with an
unpredicted sudden change, temporal uncertainty (Sutton, Baren, Zubin, & John, 1965),
and to selective attention (Ford, Roth, Dirks, & Kopell, 1973; Hillyard, Hink, Schwent,
Picton, 1973) have been demonstrated, the role of these components in this experiment
should be cautiously interpreted. However, the P3 is not the initial ERP index of target
detection. Studies have tested earlier target detection effects in the Nl, N2, and
71
Selection Negativity at scalp sites over modality specific areas in the occipital, posterior
parietal and inferior temporal cortex (see review by Mangun, 1995; Naatanen, 1992).
The present experiment used 32 channel ERPs (both average reference and radial
current density representations) in a simple visual target detection (oddball) task adapted
from Courchesne, Hillyard, & Galambos (1975), in which infrequent targets
(symmetrical or asymmetrical Chinese characters) were interspersed into a stream of
frequent standards (symmetrical or asymmetrical Chinese characters).
6.3.1 Method
Participants. Participants in this experiment were the same as those in Experiment 4.
Design. This was a mixed design with repeated measures. The participants were tested
on both behavioural changes (i.e., reaction time and response accuracy) and ERPs.
Stimuli and procedure. The stimuli were 10 symmetric Chinese characters, e.g., HI (gu3
- hill) and (gaol - lamb) and 10 asymmetric Chinese characters, e.g., (zha4-
grasshopper) and % (lu3- bow), which were matched with frequency, structure and
topological properties (Appendix F). The stimuli size was of 0.780 high and of 0.72
wide of visual angle. Two of the stimuli were presented 20% of the time (target) and the
other characters were presented 80% of the time (standard).
72
At the beginning of the test, a fixation cross was shown at the centre of the screen.
Symmetrical and asymmetrical Chinese characters were tested separately. In the
symmetric condition, only symmetric Chinese characters were presented one by one in
white against a black background and in a random order across the total 250 trials at the
centre of the screen. In the asymmetric condition, except that the stimuli were
asymmetric Chinese characters, other designs were same as those in symmetric
condition. The participants were asked to respond to the target with the thumb of one
hand and to the standard with another thumb as quickly and as correctly as possible (see
Appendix H for detailed instructions). The intertribal interval duration varied slightly
from trial to trial in order to avoid a habituation (average ISI 1.30 sec, ranging from 1.25
sec to 1.35 sec). A practice session with the same stimuli but different sequence
preceded each condition before the test. Participants were given a 30-second rest after
the first 125 trials. After having finished the first condition (symmetric or asymmetric),
participants were given a 2-minute rest. In this period, experimenter tested the
Nuroscan system again and added some electrical gel to the caps if necessary. After the
practice session, participants began to participate in another condition.
To balance the habituation of hands, half of the participants responded with the left
thumb for target and the right thumb for standard, and others reversed the response
pattern. In addition, participants were also balanced in the sequence of tests. That is,
half of the participants were tested with symmetric-asymmetric order and another half
with the reversed order. Participants were tested individually in a dimly lit room. The
tests lasted approximately 15 minutes but the whole experiments including hair cleaning,
73
cap equipping, Neuroscan system reset and testing took about one hour for each
participant. The reaction times and error ratios were recorded for each participant.
EEG recordings
The EEG recording procedure and parameter were the same as in Experiment 4.
Data analysis
Three participants were excluded for further analysis due to excessive EEG artifacts and
response errors (over 20% for target and over 10% for standard).
6.3.2 Results
6.3.2.1 Behavioural Data
The behavioural results are shown in Table 22. Symmetry effects dissociated between
symmetric and asymmetric conditions. Only symmetrical targets were proven to be
judged faster than asymmetrical targets, but no difference was shown in standard stimuli.
Table 22 Mean reaction times (RTs) and response errors (ERRs) in symmetric and asymmetric conditions (n=37)
Symmetric Asymmetric t P Target
RT (ms) 492.70 ±50.68 511.76 + 58.42 2.57 0.02 ERR 0.1032 + 0.056 0.1027+0.062 0.043 0.97
Standard RT (ms) 398.16 ± 64.39 406.93 ±70.75 1.24 0.22 ERR 0.025 + 0.025 0.023 ±0.023 0.65 0.52
74
6.3.2.2 ERP data
Only significant EEG data were shown in Table 23-28 (other EEG data listed in
Appendix J3-J8).
For targets which usually need more effort, the time course of Nl, P2, N2 and P3 (see
Appendix J3, J4, J5 and J6) indicated that the processes begin at the temporal lobes,
then to the frontal lobes which may produce an attention, then to the occipital lobe,
again to the temporal lobe and the frontal lobes, then before returning to the parietal-
occipital lobes where a perceptual detection may occur, then again from the temporal
lobes to the frontal lobes where a decision making probably happens, then the temporal
lobe where semantic information may be activated, then to the central area for action
and ends at the parietal-occipital area, the visual cortex.
For standards that usually need less effort, the time course of Nl and P2 (see Appendix
J7 and J8) revealed that the processes start at the central areas, then immediately shift to
the frontal lobe which is presumably an attention process, then to the parietal-occipital
area and returns to the frontal lobes and to the central areas and end at the parietal-
occipital area, the visual cortex.
For the Nl component, the anterior frontal site, Fpl, is involved. It is supposed the
time course of Nl, probably associates with a pre-attention process, that is, the
orientation to the stimuli.
75
The P2 component heavily and extensively contributes to the symmetry effect although
other components also give their contribution. The anterior frontal sites, i.e., F7, F3, Fz,
and F4, left temporal sites, i.e., Ft7, Fc3 and C3, central sites, i.e., Fez and Cpz, right
temporal sites, i.e., Fc4 and Ft8, and parietal-occipital sites, i.e., P7, P3 and P8 are found
to involve in the process.
In the target condition, the significance tests for amplitude showed a shift of ERPs for
asymmetric condition, especially P2 to a negative direction. This significant shift
indicates that processing asymmetrical information is burdened more than processing
symmetrical information for targets. Although a higher spatial resolution test such as
fMRI is needed to specify the process, from the current results it is inferred that the
anterior frontal area and parietal-occipital area are believed to be crucial for symmetry
detection. In the standard condition, however, the significance tests for amplitude
showed a shift of ERPs for asymmetrical information especially P2 to a positive
direction. Accordingly, the shift indicates that processing asymmetrical information is
easier than processing symmetrical information, which failed to show this effect in a
behavioural test. It is interesting that a dissociation took place between the target and
standard conditions.
The N2 component in the anterior frontal site, F3, central area, Cpz, and the parietal-
occipital sites, i.e., P7, P8, 01, and 02 is reported to show significant differences in
processing symmetry.
76
As P3, the cential site, Cpz and the parietal-occipital site, P3 are highly associated with
the semantic process.
To summarise, given the primitive feature of symmetry processing and the function of
the cortex, the anterior frontal lobe and the parietal-occipital area are more likely to
involve the above processing. It may need a higher spatial resolution technology, such
as functional magnetic resonance imaging (fMRI) or positron emission tomography
(PET) to more precisely locate the activations for processing symmetry.
Table 23 Mean latency and amplitude ofNl for targets across the scalp (n=30) Electrode Amplitude Latency Spot Sym Asym T p Sym Asym t p Anterior Frontal Lobe Fpl 1 0 5 . 8 7 ± 15.61 1 1 1 . 2 0 + 1 5 . 6 2 2.01 0.05
Note: Sym-symmetry; Asym-asymmetry. Seven participants' EEG data were further excluded due to the bad waveform.
Table 24
Electrodc Spot Sym
Amplitude Asym T P Sym
Latency Asym / P
Anterior Frontal Lobe F7 8.92 + 2.44 8.06 + 2.73 2,59 0.02
F3 10.70 + 3.35 9.66 + 2.83 2.26 0.03
Fz 11.27 + 3.77 10.63 ± 3 . 4 4 1.96 0.06
F4 10.66 + 3.57 9.91 ± 3 . 0 7 2.48 0.02
Left Temporal Lobe Ft7 7.65 + 2.19 6.93 ± 2 . 5 8 2.45 0.02
Fc3 10.07 + 3.16 9.29 ± 2 . 8 3 3.21 0.01
C3 8 . 0 6 ± 2 . 7 5 7.59 ± 2 . 8 4 1.98 0.06 181.67+23.34 197.53+40.13 2.18 0.03
Centra! Area
Fez 10.91 ± 3 . 8 2 10.11 ± 3 . 2 2 2.85 0.01
Cpz 182.80 + 29.00 198.13 ±43 .46 2.56 0.02
Right Temporal Lobe Fc4 9.90 ± 3 . 3 1 9.18 ± 3.16 2.43 0.02
Ft8 7.75 ± 2 . 5 7 7.18 ± 2.39 1.85 0.07
Parietal-Occipital Area
P7 0.55 ± 1 . 7 9 1.55 ± 1 . 9 9 3.71 0.01
P3 3.66 ± 2 . 7 0 4.63 ± 3 . 8 0 1.75 0.09
P8 1 . 0 0 ± 2 . 6 2 2.09 ± 2 . 5 9 3.41 0.01
77
Electrode Spot Sym
Amplitude Asym t P Sym
Latency Asym t P
Anterior Frontal Lobe
F3 312.54 ± 21.91 325.00 ±29 .72 2.02 0.05
Central Area Cpz 0.29 + 3.87 -0.55 + 4.29 1.76 0.09 291.87 ±32 .19 274.93 ±42 .00 1.88 0.07
Parietal-Occipital Area
P7 266.13 ±39 .63 293.93 ± 3 9 . 5 2 2.72 0.01
P8 278.80±42.62 296.00 ± 5 0 . 2 4 1.98 0.06
0 1 264.13 ±34 .32 291.20 ±30 .51 3.73 0.01
0 2 266.00±49.58 292.20±48.22 2.50 0.02
Table 26 Mean latency and amplitude of P3 for targets across the scalp (n~30)
Electrode Spot Sym
Amplitude Asym / p Sym
Latency Asym t P
Central Area
Cpz 19.16 ±4.94 18.01 ±5.51 1.83 0.08
Parietal-Occipital Area
P3 470.13 ±32 ,73 457 .40± 35.33 1.98 0.0 6
Table 27 Mean latency and amplitude ofNl for standards across the scalp (n=37) Electrode Spot Sym
Amplitude Asym t p Sym
Latency Asym t P
Anterior Frontal Lobe F3 1 0 5 . 4 6 ± 12.49 110.11 ± 1 5 . 2 2 2 .55 0.02
F 4 105.84± 13.16 109.51 ± 1 4 . 5 0 1.85 0.07
Right Temporal Lobe Tp8 138.22 ± 39-93 123.08 ± 39.15 2.00 0 .05
Parietal-Occipital Area P7 -4.45 ±2.67 -4.85 ±2.59 3 .04 0.01
Sym Latency
Asym
312.54 ± 21.91 3 25.00 ± 29.72
1.76 0.09 291.87 ±32 .19 274.93+42.00
266.13 + 39.63
278.80+42.62
264.13 ±34 .32
266.00+49.58
293.93 + 39.52
296.00 + 50.24
291.20+30.51
292.20+48.22
Electrode Spot Sym
Amplitude Asym Sym
Latency Asym
Central Area
Cpz 19.16 ± 4 . 9 4
Parietal-Occipital Area
P3
18.01 ±5 .51 1.83 0.08
2.02 0.05
1.
470.13 ±32 ,73 457.40±35.33 1.98
0.07
2.72 0.01
1.98 0.06
3.73 0.01
2.50 0.02
Table 26 Mean latency and amplitude of P3 for targets across the scalp (n~30)
0.06
Table 27 Mean latency and amplitude ofNl for standards across the scalp (n=37) Electrode Spot Sym
Amplitude Asym Sym
Latency Asym
Anterior Frontal Lobe F3
F4
Right Temporal Lobe Tp8
Parietal-Occipital Area P7 -4.45 ±2.67 -4.85 ±2.59
105.46± 12.49
105.84± 13.16
3.04 0.01
110.11 ±15.22 2.55 0.02
109.51 ±14.50 1-85 0.07
138.22 ± 39.93 123.08±39.15 2.00 0.05
78
Table 28 Mean latency and amplitude of P2 for standards across the scalp (n=37)
Electrode Spot Sym
Amplitude Asym T P Sym
Latency Asym t P
Anterior Frontal Lobe
Fpl 8.03 ± 2 . 6 3 8.83 ± 2 . 9 6 3.31 0.01
F7 7.38 + 2.22 8.05 ± 2 . 2 9 3.54 0.01
F3 8.62 ± 2 . 5 4 9.68 ± 3 . 1 4 3.61 0.01
Fz 8.53 ± 2 . 7 8 9.64 + 3.09 4.82 0.01
F4 8.31 ± 2 . 5 5 9.3 7 ± 3 . 0 0 4.67 0.01
Left Temporal Lobe
Ft7 6.11 ± 2 . 0 8 6.72 ± 2 . 2 5 3.90 0.01
Fc3 7.67 + 2.44 8.74 ± 2 . 6 5 4.97 0.01
T7 4.34 ± 1 . 8 3 4.93 ± 2 . 0 3 3.48 0.01
C3 5.99 ± 2 . 2 2 6.98 ± 2 . 5 8 4.89 0.01
Tp7 1.94 ± 1 . 4 4 2 . 3 2 + 1 . 7 9 1.99 0.05
Cp3 4 . 6 3 + 1 . 8 1 5.13 + 2.12 2.97 0.01
Central Area
Fez 8.19 + 2.84 9 . 4 1 + 3 . 1 7 4.71 0.01
Cz 7.62 ± 2 . 6 8 8.88 ± 2 . 9 8 5.79 0.01
Cpz 6.88 ± 2 . 3 2 7.66 ± 2 . 6 3 3.34 0.01
Right Temporal Lobe
Fc4 7.64 ± 2 . 3 9 8.64 ± 2 . 8 0 4.64 0.01
C4 6,23 ± 2.39 7.21 ± 2 , 8 1 4.33 0.01 199.14+40.80 188.22 + 28.44 2.08 0.05
T8 4.46 ± 1 . 7 5 4.95 ± 2 . 0 5 2.39 0.02
Cp4 216.65 ±51 .39 206.65 ±43 .75 1.75 0.09
6.3.3 Discussion
There was an enhancement of the Nl in latency to asymmetrical stimuli indicating
identifying an asymmetrical Chinese character is more difficult than a symmetrical one.
Research has found that the primate visual system is bifurcated into two processing
pathways, a dorsal pathway projecting to the posterior parietal lobes that encodes spatial
location information and a ventral pathway projecting to inferior temporal cortex (IT)
that encodes the physical features of visual s u b j e c t s (Ungerleider & Haxby, 1994 ;
79
Ungerleider & Mishkin, 1982). The results here showed a fairly extensive activation in
temporal lobes, which is consistent with the above findings. The frontal cortex has been
regarded as a neural executive, which regulates and sequences related stimulus inputs,
motor outputs and target detection (Luria, 1973; Posner & Petersen ,1990; Pribram,
1973). Human hemodynamic neuroimaging studies have shown activation both in
frontal cortex and in modality specific areas of occipital, posterior parietal and inferior
temporal cortex in visual selective attention and target detection tasks (Corbetta, Miezin,
Dobmeyer, Shulman, & Petersen, 1990; Roland, 1985), which is consistent with the
results in this experiment. To detect a symmetrical feature, it is obvious that the
processing should also involve the frontal lobes (the executive centre of brain) and
parietal-occipital lobes (visual sensation and perception centre). The results are also
consistent with the prediction and previous studies using other tasks.
80
CHAPTER 7
GENERAL DISCUSSION AND SUMMARY
7.1 Psycho-geometric Theory of Chinese Character Reading
All the experiments conducted here are intended to investigate and examine a psycho-
geometric theory of Chinese character reading (Kao, 2000). This theory is based on
investigations on the evolution and construction of Chinese characters, and a series of
experiments on topological processing of visual perception and on Chinese character
writing.
7.1.1 Chinese Characters and the Characters Structuring
The reading of Chinese characters involves a process of visual spatial structuring of the
elements of characters. They are read within a subdivided square in which the execution
of strokes into characters, the shaping of the character, and the spacing and framing of
the character occur. The execution refers to the basic formation of strokes within a given
character and their structural interrelationships. The shaping is a process of organising
the various strokes to conform to the style of the character, and the spacing and framing
is the layout and spacing of characters, as well as their position in columns and rows
(Billeter, 1990).
81
The purpose of shaping a character is to ensure its coherence and autonomy relative to
other characters in a given reading context. The formation of a character involves
inscribing it in a square and then centring it for each character, it is important that its
centre coincides with the midpoint of the square and its strokes be aligned according to
the visual-spatial patterns of the previously established character. This is a visual effect
quite different from that of English letter formation.
Central to the perceptual organisation of the character from within the reader's cognitive
experience is some properties underlying the visual-spatial structure of Chinese
characters. On a more visual spatial level, several topological principles of visual
perception are pertinent to the cognitive map of the character produced in the act of
reading. These include the presentation of global and detailed views of the objects,
connectivity, inside-outside relationships, closure, co-linearity, size, orientation and
symmetry. In the process of reading, the reader's perceptual shaping of the character is
influenced by the patterns within the character which cause his/her perceptual and
cognitive conditions to engage in corresponding adjustments and representations. This
dynamic process would result in his perceptual, cognitive and physiological responses to
vary in respect of the visual-spatial configurations of the character (Kao, 2000).
Examples of Chinese characters containing different composition of the visual
geometric properties are provided, for the purpose of illustration, in a more stylised print
form.
82
Symmetric characters Parallel characters Connected Characters
H BB M °r
Jll § I I ttl X ft • R
l$l S ^
Non-svmmetric characters Non-parallel characters Non-connected characters
M M % a r &
!$b / §
sh A n <b
i t Jll A R
Closed characters Linear characters
ffl • B o° 1 S ES Da
I B B t t
Unclosed characters Non-linear characters
% Jo ~EL
* £ & A
St A 3 &
Parallel characters Connected Characters
H ffl M °T
Jll S !pi L±J l$l % § ^
Non-parallel characters Non-connected characters
M MS % a r &
M !& /S
/ h A n ' h 1 L j l l A H
Closed characters Linear characters
E 0 O B g d D
M @ ES Ob
3E B HI D±
Unclosed characters Non-linear characters
± -EL 3 %
7X2 Principles of Chinese Character Writing
A conceptual framework has been advanced to highlight the act of Chinese character
reading. The following is a summery of some of the key points (Kao, 2000).
83
A square is a peifect geometric pattern as it incorporates hole, linearity symmetry,
parallelism, connectivity, and orientation all in one figure. A Chinese character is seen
to portray an imagery or visible square. With an implied correspondence between the
shapes of the square and the character, the characters may vary in terms of the extent to
which they possess the geometric properties of the square as well as other non-
accidental properties. Research has shown these advantages in human cognition and
bodily activities in Chinese calligraphic writing, e.g., psychophysiological changes,
taking place during calligraphic writing that varying with the geometric variations of the
characters, include heart-rate, respiration, blood pressure, finger pulse volume, EMG,
EEG and skin temperature (Kao, Lam, Robinson & Yen, 1989). Particularly, Kao &
Goan (1995) found that cognitive changes associated with the geometric variations of
the characters include clerical speed and accuracy, spatial ability, abstract reasoning,
digit span, short-term memory, picture memory, and reaction time.
Stylistic variations of Chinese characters reflect individualised forms of the strokes
organisation in the character. In the recent years, Kao (2000) has conducted a series of
studies to tackle the issues on the cognitive correlates of the visual geometric properties
of Chinese characters. These are reviewed from the perspective of visual recognition
associated with Chinese reading and handwriting. The underlying hypothesis is that
variations of the visual-spatial properties of the characters would result in corresponding
cognitive changes in the process of Chinese reading.
7.1.3 Effects of Character Geometricity on Visual Recognition
84
A square is the simplest visual pattern (Koffka, 1935). It incorporates, as in the case of a
Chinese character, not only patterns such as co-linearity, closure, symmetry, continuity
and balance, but also other properties of connectivity and parallelism. Characters may
vary in terms of the extent to which they possess the geometric properties of the square
in addition to its geometric configuration in character structure. Kao recently (2000)
analysed the most primitive writing systems including the Egyptian writing, the
Sumerian script and the Chinese oracle script. He found the existence of common visual
properties in primitive writing systems: tendencies of being pictographic closed
symmetric and parallel. These features of the primitive writing systems are direct and
natural projection of our perception of the outside world. Chinese script of the present
day remains the only written language that inherits most of the distinctive visual
characteristics of its ancestors.
To test whether the visual properties adhered to the characters could affect the
orthographic processing of Chinese character, we conducted two experiments (Chen &
Kao, 2002). The first experiment hypothesised that the visual-spatial properties inherent
in the characters are quickly utilised to facilitate the orthographic processing of the
characters. The visual-spatial properties considered were linearity, parallelism, closure
and symmetry (see Table 29 for examples). In a within- subject design with two levels
of character complexity (fewer than 9 strokes versus more than 10 strokes) and three
levels of visual-spatial properties of pairs of character stimuli (rich-rich, rich-poor, and
poor-poor), fifty grade 4 children participated in a visual judgement task measured by
85
reaction times and errors. The results suggested that the visual-spatial properties are
utilised quickly enough to provide a perceptual basis for Chinese character processing.
Furthermore, the visual judgements were more quickly produced and had fewer errors
for pair characters with rich (rich-rich) visual properties than those with poor (poor-poor)
visual properties. These findings were consistent with the hypothesis on the facilitating
effect of non-accidental properties on orthographic processing of Chinese characters.
The richness of the geometric properties inherent in the Chinese characters affects our
perceptual and cognitive processing directly (Chen & Kao, 2002).
Table 29
Richness of the geometric properties in Chinese characters
Visual Property Character Sample
p^ l H O O i
P+L+C M, n±, I'J, I I
P+L+c+s ffi.JK.P,*
Notes: P = Parallel, L = Linear, C = Closure, S = Symmetric
In a second experiment (Kao & Chen, 2000), Chinese characters presented in the square
and rectangular shapes were compared in a visual recognition task. Measured by
response time to the onset of the stimulus character on a computer screen, the characters
presented in the squared style were responded to more quickly than those presented in
the rectangular style. A second study examined the effect of angularity of stroke linkage
in Chinese characters as well as in English letters on a recognition task (Kao & Chen,
86
2000). Using college students and measured by multiple recognition tests, the subjects
performed significantly better in characters and letters with smaller angles than with
larger angles. A recently completed experiment compared the functional localization in
the cortex in reading Chinese characters as well as Chinese Pinyin (Kao, Chen, Li,
Mathews, Fu & Gao, 2000). The latter is a phonetic system based on the spelling of
Chinese sounds by a visual script comprising largely English alphabetic letters.
Using the functional magnetic resonance imaging (fMRI) technique, Kao et al. (2000)
found that reading Mandarin characters involves more and different cortical sites for
processing than Pinyin reading of the same Chinese sounds, although at the same time,
both types of reading share certain common sites. A difference in cortical activation has
therefore been observed between the two scripts, which vary in terms of the visual-
spatial form and complexity. This initial finding is line with our theoretical expectation
on differential neurocognitive processing of different scripts as a function of the
differentiation and richness of their respective visual spatial properties therein. It has
implications toward our understanding of the visual spatial activating effects of the CCH,
because this graphic act involves visual and neurocognitive processes, but also motoric
action.
These three experiments have provided some empirical evidence to the validity of our
stated hypothesis, that is, characters having some geometric properties, such as
connectivity, linearity, hole(s) and symmetry are processed quickly. This study, through
a visual match task and a lexical decision task, has shown the geometric property effects.
87
7.2 Topological Perception and Functional Hierarchy in Form
Perception
According to a feature integration theory (Treisman, 1988), visual identification should
include two processes, i.e., feature detection and integration. Feature detection such as
colour and size occurs earlier than integration. Treisman (1988) does not include a
topological processing in the early stage, that is, her theory holds that a global
processing, if it really exists, should take place later than a feature detection process.
Chen (1989) argued against this theory and proposed a more primitive topological
process appearing earlier than a feature detection process.
Chen (2001, p. 288) argued that, in addressing the most fundamental question of
'Where visual processing begins', the theories of perception can be segregated into two
contrasting lines of consideration: 'early feature-analysis' (that is, from local to global
processing) and 'early holistic registration' (that is, from global to local processing).
Early feature-analysis view holds that objects are initially decomposed into separable
properties and components, and only in subsequent processes are objects recognised, on
the basis of extracted features. The early holistic registration approach supports a 'from
global to local' view that Wholes are organized prior to perceptual analysis of their
separable properties or parts, as indicated by the conception of perceptual organization
in Gestalt psychology.
The problem of feature binding is then essentially a consequence of the particular local-
to-global assumption. However, from the global-to-local perspective, the problem of
feature binding may be a wrong question to ask to begin with, while the Gestalt concept
of perceptual organization serves to reverse this inverted position. Inspired by the
analysis oi invariants over transformations, particularly shape-changing transformations,
Chen (2001; Todd, Chen & Norman, 1998) developed a topological approach to
describe precisely the nature and rules of perceptual organization, with respect to
Klein's Erlangen Program. Klein's Program provides a formal way to define a kind of
geometric properties as a kind of invariants preserved under a specific transformation
group, and stratify branches of geometry with reference to their relative stabilities under
this transformation group. The more general is a transformation group, the more
fundamental and stable are the geometric properties preserved under this transformation
group. Particularly, topological properties, such as connectivity and holes, are most
fundamental and stable, because the topological transformation group ('one to one and
continuous') is the most general one.
Alternative geometries can be devised for which constraints on corresponding
transformation groups are varied. Along the Program, a hierarchy of geometries were
built up in an ascending order of relative stability: Euclidean geometry, affined
geometry, projective geometry, and finally topology with the highest stability. A fairly
large set of behavioural data revealed that topological perception plays a fundamental
role in perceptual organizations, such as distinguishing figure from background, parsing
visual scenes into potential objects, and performing other global, Gestalt-like operations.
89
Particularly Chen and his colleagues (Chen, 2001; Todd, Chen & Norman, 1998) found
that the relatives salience of different geometric properties is remarkably consistent with
the hierarchy of geometries stratified by Klein's Program. Since only from the
perspective of the invariants over the topological transformation can the precise
meaning of topological properties be grasped, and since at the core of Klein's Program
lies the idea of transformations and invariants preserved under transformations, this
framework claims that visual perception may work by abstracting invariants of forms
under changes, and the primitives of visual representation should be considered
invariants at different levels of geometry, including particularly topological invariants
(as opposed to concrete and simple components of objects, such as line-segments
commonly accepted). Form such perspective of invariance perception of this framework,
the relationship between different geometrical properties, particularly between global
topological perception and perception of local geometrical features, can be clarifies as a
functional hierarchy of form perception. That is, global topological organization is prior
to the perception of local features, and the time dependence of perceiving form
properties is systematically related to their structural stability under change, in a manner
similar to the Klein's hierarchy of geometries: in a descending order of stability or from
global to local, topological properties (typically the number of holes), projective
properties (typically co-linearity), affined properties (typically parallelism), and
Euclidean properties (typically orientation ,location, and mirror-symmetry). Chen
argued that these results demonstrate strong evidence for those invariants at different
levels of geometries have psychological reality as the primitives of visual representation.
Chen's theory is consistent with the observations on the development of mathematics in
90
children by Piaget (1953), in which Piaget found children first developed the concept of
topological geometry and then other geometries, which is reversed to the development
of geometry (from Euclidean geometry in ancient Greece to topology in the late
nineteenth century).
Evidence supporting topological perception is illustrated in topics of visual sensitivity
(Chen, 1982a, 1990), apparent motion (Chen, 1985; Zhuo, Zhou, Rao, Wang, Meng,
Chen, Zhou, & Chen, 2003), illusory conjunctions (Chen & Zhou, 1997), and the
relative salience of different geometric invariants (Han, Humphreys & Chen, 1999a,
1999b; Pomerantz, Sager, Stoever, 1977; Todd, Chen & Norman, 1998).
The visual matching task only produced a topology effect in Chinese characters with
high frequency but not in low frequency characters. On the Contrary, the direct priming
task induced an effect in Chinese characters with low frequency but not in those for high
frequency counterparts. As pointed out earlier, a Chinese character with high frequency
is usually processed through a top-down process. These characters can access to the
lexicon with less effort, say, automatically. It is not necessary to take advantage of other
redundant information to process a character with high frequency according to an
economical principle, which has important biological significance (see Kahneman,
1973). The author believed the higher complexity of the Chinese characters with low
frequency prevented a topology effect from occurring in a visual matching task and a
conceptual driven process, rather than a perceptual or data driven process, in the high
frequency condition failed to activate a priming effect (See Moscovitch, 1992). It is
91
expected that if the presentation environment changes, such as using more rapidly
stimuli or reducing discrimination resolution rate of targets, the effects may manifest. In
addition, I claimed that the low visibility has damaged the identification of characters
with low frequency. It should be cautious to draw this conclusion particularly before an
experiment, that has matched the visibility between the characters with high and low
frequencies (i.e., relatively reduce the complexity of characters with low frequency), has
carried out.
Although this study could not prove which happened earlier, the results have clearly
shown an involvement of topological processing in identifying Chinese characters in a
tachistoscopical environment. That is, topological organization of the characters affects
Chinese character identification. The results are also supported by the subsequent ERP
study. The conclusion reminds us that a topological involvement should be considered
when we are designing an experiment in Chinese language reading and writing. In
particular when a morphological priming paradigm (i.e., a prime which is
morphologically similar to a target will reduce the reaction time for the target) is
adopted, we should treat topology as a control variable. The findings in Experiment 2
showed that a character (prime) which is topologically equivalent of the following
character (target) can facilitate the response to the target, revealing a topological
priming effect. That is, there may be a confounding of variables in a morphological
priming task because topology also contributes to the priming effect. In fact, no
previous studies in Chinese language cognitive research have distinguished this
92
difference. So, it is recommended to conduct a meta-analysis for all the studies using a
morphological priming paradigm.
7.3 The Neural Mechanism of Geometric Property Processing:
Evidence in Topology and Symmetry
A follow-up event-related potential (ERP) study revealed that topological processing
produces an early positive component and then an early negative component, with both
occurring earlier than the reported PI and Nl respectively. The results indicated that
topological processing takes place at a very early stage and probably is pre-attentive
which supports the hypothesis by Chen (1982a, 1989) and found some brain areas
including some locations in the temporal lobe, the anterior frontal lobe and the occipital
lobe, associated with the process, which are consistent with the previous studies by Han,
Fan, Chen, and Zhuo (1997). The working loop of the activation should be analysed
further, especially in contrast to an fMRI or positron emission tomography (PET) study
to more precisely locate the activation areas.
ERP measurements showed a dissociation processing symmetrical and asymmetrical
information between target and standard conditions. And an extensive involvement of
P2 may indicate the processing is strongly driven by an exogenous component and rely
on the processing of physical features of the Chinese characters, such as symmetry in
this study. The fact that only an Nl and P2 occur in processing symmetrical and
93
asymmetrical information in the standard condition indicated that the process should
finish at the time course of P2, that is, less than 236 ms (the longest latency in P2).
7.4 Present and Future
7.4.1 Implications
Much research in Chinese character processing in the past three decades has been
focussed on the role played by phonological processing in character processing (See also
Kao, Leong and Gao, 2002). This study took another perspective, i.e., a pattern
recognition perspective, to investigate how geometric properties in a Chinese character
affect the recognition and identification. The present study provides evidence for the
psycho-geometric theory of Chinese character reading, which is a unique and
completely new exploration for Chinese reading. This exploration has impacts on the
construction of linguistic processing and enriches the theory of Chinese language study.
Furthermore, the study erected a link between Chinese character processing and pattern
recognition. It is important to study the unique features of a character, that is, the
geometric properties.
In practice, the findings are helpful for Chinese character learning. It is expected that
children and foreigners who are learning Chinese characters may start from the
characters having some geometric properties such as hole, connectivity, symmetry and
straight lines.
94
7.4.2 Limitation
The conceptual development of the topological properties for character processing needs
further clarification, because Chen's work deal with pure visual forms without the
semantic context, while the present study tackles content-rich Chinese characters.
Similarly, the psycho-geometric properties should be more clearly defined, characterised
and distinguished from the mathematically defined topological properties.
It is regrettable that only male subjects were used in this study. Since there were fewer
female students in the military, we could only get enough male participants to
participate in the experiments. Although no research has shown a sex difference in
geometrical processing, it would be preferable to involve enough female subjects in
future.
7.4.3 Present and Future Directions
The present study examined the geometric processing of Chinese characters, which is
interpreted by a psycho-geometric theory through a behavioural and ERP approach.
During the last decades, research on Chinese character processing has been heavily
focused on phonology and semantic processing. This study explored a new direction to
investigate how geometric properties are crucial recognise a character. It is important to
point out that sort of studies are necessary to clarify the cognitive and neural mechanism
95
of Chinese character reading. I have tried ERP in this study, it is reasonable to think of
other neuroimaging approaches, such as fMRI, PET and magneto-encephalography
(MEG) in the geometric processing of Chinese characters. In fact, some fMRI studies in
phonological processing of Chinese characters have been published (e.g., Chee, Tan, &
Thiel, 1999 Me, Tan, Tang et al, 2003; Tan, Spinks, Gao et al., 2000).
Applying the psycho-geometric theory to Chinese character writing is also an important
move, particularly in learning how to write Chinese characters for children and
foreigners. In the past two years, I have closely observed my son, Tian Tian who is now
in his three years old, to learn to write Chinese characters. Interestingly, almost all the
first characters he has learned are those having straight lines, holes, symmetry, and so on.
The examples of his first learned characters include '41 ' (centre), 'J3' (moon), ' 0 '
(sun), 'I'u'i' (high). After almost 6 months, he gradually can write other characters, like
VX' (water).
7.5 Summary
Over 60% of Chinese characters are of the left-to-right form, around 20% of the top-to-
down form and the remaining of fewer than 20% of other structures. The frequency of
characters is inversely proportional to the number of strokes, i.e., the more frequently
the characters are used, the fewer strokes they will have. Specifically, for low frequency
characters, almost no correlation exists between frequency and stroke number. For high
96
frequency characters, they will have about two strokes fewer than those with mid-
frequency or around three strokes fewer than those with low frequency.
Most of the frequently used Chinese characters (65% in total) consist of hole(s) with
most of their containing 1 or 2 holes. No apparent difference is revealed in the
distribution of hole(s) across frequency (959 characters for high frequency, 1,069 for
mid-frequency and 945 for low frequency).
Only 6% of the characters are connected in construction but the distribution of this
property (characters with connectivity) is extremely skewed. Among the first 300
characters around 30% of them are connected and 71 percent of the connected
characters are of high frequency, suggesting that the most frequently used Chinese
characters are connected.
There are 260 characters with high linearity and 212 with low linearity but this finding
may not apply to the traditional Chinese characters. Thirty-nine percent of the
characters are fully or partially symmetric and most of the fully symmetric characters
are of high frequency. Partially symmetric or asymmetric characters are approximately
equally distributed across the frequency of usage. There exist some characters with two
or more symmetries. Moreover, there are 86 characters in total with weak balance, that
is, 9 with high frequency, 31 with mid-frequency and 46 with low frequency.
97
Neither frequency effect was found in both topologically equivalent and different
chaiactets, nor did the effect occur in either a visual matching task or a lexical decision
task (priming paradigm). As discussed by Ferstl & d'Arcais (1999), a frequency effect
is more likely to happen in a semantic process. Unfortunately, the process involved in a
visual matching task and a priming lexical decision task, both of which are heavily data-
driven, unintentionally diluted the semantic involvements or conceptual-driven
processing. Thus, it was reasonable to conclude it should not manifest a frequency effect,
although we should be also cautious in our interpretation before any further studies are
conducted.
No linearity effect was found for both Chinese characters with high frequency and those
with low frequency. The causes of these results are still unclear. If the results can be
further confirmed by other studies, it may be important to claim that linearity is not a
positive factor of Chinese character reading. If so, the psycho-geometric framework of
Chinese reading and writing by Kao (2000) may be revised to adapt this conclusion.
In a series of four experiments through a classic lexical decision paradigm, we found a
symmetry, a closure, and a structure (radical arrangement) effect in Chinese characters
with low frequency but not for high frequency, except for the linearity effect. The
causes of this phenomenon is those Chinese characters with high frequency induced
automatic processing requiring less effort which make the other perceptual cues, such as
symmetry, closure and construction, less useful (See Forster, 1994, for a search model
and McClelland & Rumelhart, 1981, for a connectionist model to account for frequency
98
effects). The results proved that symmetry, closure and a top-to-down form are a
positive factor in Chinese character reading, which coincide with the psycho-geometric
investigation of the commonly used Chinese characters in Chapter 3 of this study. The
results also implied that we should think of these factors which may affect Chinese
learning when we conduct research using Chinese characters as stimuli or when we
develop other research work with Chinese such as a simplification movement on
Chinese characters.
An event-related potential (ERP) study has shown that topological processing produces
an early positive component and then an early negative component, with both occurring
earlier than the reported PI and Nl respectively. The results indicated that topological
processing takes place at a very early stage and probably is pre-attentive and discovered
some brain areas including some locations in the temporal lobe, the anterior frontal lobe
and the occipital lobe, associated with the process.
ERP measurements showed a dissociation processing symmetrical and asymmetrical
information between target and standard conditions. And an extensive involvement of
P2 may indicate the processing is strongly driven by an exogenous component and rely
on the processing of physical features of the Chinese characters, such as symmetry in
this study. The fact that only an Nl and P2 occur in processing symmetrical and
asymmetrical information in the standard condition indicated that the process should
finish at the time course of P2, that is, less than 236 ms (the longest latency in P2).
99
Notes:
1 The Chinese language also has an alphabet invented in the late Qing Dynasty, which was created to describe the pronunciation of mandarin or Putonghua. With the view of annotating Chinese characters in the Western alphabet, a new romanisation called Pinyin was adopted in the Chinese mainland since 1950's, which can better describe Chinese pronunciation than the Wade-Giles system, except that one has to grasp it with a slight change in pronouncing some of the consonants from the view of English language. The number followed by the Pin-Yin indicates the tone of this character. There are four intonations or tones in Putonghua namely: ' 1' represents Ying Ping, a low flat tone, e.g., A (bal-eight), '2' Yang Ping, a high flat tone, e.g., fflt (ba2-pull), '3' Shang Sheng, an ascending tone, e.g., IE (ba3-target), and '4' Qu Sheng, a descending tone, e.g., @ (ba4-father). (see Ann, 1987)
2 High frequency refers to more than 50 occurrences and low frequency to less than 5 occurrences out of 1 million occurrences, and the remaining are in mid-frequency.
3 A pseudo-Chinese character is made according to the orthographic principles of a real Chinese character but it is never a real Chinese character.
100
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Group Group
1 + X • 1 i f
2 a t 2 fK
3 f f Pf 3 np 5®
4 A r 4 m &
5 R Jf 5 i e IS ft
6 n a i 6 i & £
7 i t - b A 7 b ih
8 § iftL f5n 8 / L
9 lLj — 9 J 6
10 t} * 10 s 351 n
11 % £ in 11 ft &
12 A A A 12 ft m fa
13 % % ffl 13 n£ #n @
14 % M s 14 m IP® n
15 # R 0 15 t i 0
APPENDIX A
Low Frequency
Group
• i % if
% 2 m ® m
U 3 op $£ «
$ . 4 & £f
f x 5 ?E IS ft
7 i t - b A 7 b ^ ih
8 g l&L 8 *5 ^ /L
9 i l j ^ - 9 3 9 # * S
10 ^ j j & io 4- M ^
11 ^ £ in ii ft fl* &
12 A A A 12
13 3£ ^ ffl 13 R& @
14 S S S 14 90 ^ 0
15 & K 0 15 ^ ^
Note: Group 1-6 are distinguished by holes, Group 7-12 by separation/connectivity and Group 13-15
by inside-outside distinction
117
Symmetric Asymmetric Symmetric : Asymmetric * 7 ¥ % * a dhfcr /jyjN & t 4 * m 111 % s>& 5 M $3 m Stfc l''J £ ¥ n )k A ZK 31
j] £ M M s
hi IE -A. a # • & 3J
S& # # n 1-5 itt A E B
II it $>L
m & i f £
m r ft
¥ ft
APPENDIX C
Stimuli from Experiment 3b
Hieh Frequency Low Frequency
Linear P * r —•
Non-linear Linear Non-linear
± 111;
tfi$ m ± 111; £ TSC
10 lR 6
.It M
IE & m
# Iii
m # FP #
Iii w* E FP lin Pi m UK M M #f-la. # m & £
f - 5§
APPENDIX B
Low Frequency
:lt m #
x & r m
Symmetric
dhfcr m
&
& B
Jft m #
g
Asymmetric
% & JEE s w m & M
m m
•x ft
APPENDIX C
Stimuli from Experiment 3b
High Frequency Low Frequency
Linear ± lit 10 .It IE # 11
Non-linear
z & M 2
Linear
n si
«£
Non-linear
0E
w m m &
118
APPENDIX D
Stimuli from Experiment 3c
High Frequency Low Frequency Closed Opened Half-closed Closed Opened Half-closed
h -'j* is) m ¥ n |P| ft; |Hlj @ -g $ m !•- @ m m m m m m & is |l*| 1̂3 0 Sii H m & w i ft ia m I. ft ® fr s E! lis fc3 0 % fS [5| i ft Ii ® $ W 0 ^ H S IS ff n it ra iii s fi
119
APPENDIX E
Stimuli from Experiment 3d
High Frequency Low Frequency Right-to-left
ifii
M m m m # &
ast ffi
Sk m m Mi
Mi hi
m
Top-to-down
&
M K
& S8
m w
Right-to-left
© iK m,
I®
if ffi
Top-to-down
bb
faf* £
120
APPENDIX F
Stimuli from Experiment 5
Target
Standard
Symmetric Asymmetric
ife.
ii m
TSf.
121
m
APPENDIX G
Pseudo Chinese Characters Used in the Experiments
CODE 0 1 A B C D E F AAA
AAB
AAC
AAD
AAE
AAF
ABA
ABB
ABC
ABD
ABE
ABF
ACA
ACB
ACC
FF j f i
M
m m
ft
* ^
* • m ®Xi /sue
i t ££
«
cr * t=T s" M- rfj
•fe S IE
9k fi t H
BjE ft
•» a IE
fi S I
e n
3? & & s§ m IS & t& # Btfe 31 i i ©c tH W 4S Sft # K
$ S S 41 ijS H PI
A*r
t
ft
- t t
tfr
JE
-±r TO •& &C
M?P •C/»
jfc -&T z*z
& i a
m m m
m «•
m « @ i t
* jK
fcX I S
# J$
M fis *t!» /Jr3
# jGE i * #
W ft SL iff 14 ft « ®
« m ® m
& a # j® ®
BS
hi
fit*!
-**-
't> TX ^ M
* JB3 3fc « l
IS tt ffi EC If Sfc « ff II
Jig £ Ifc
m # as El # 5
^ M J$ BB ^ gfe-
^ ^ ^ ® £? £?
$ t « ? i t ffi
££ X!l I'J ill
Vll T»»*\
$ % 1 «
f t m « # f
^ i t
122
APPENDIX H
Instructions in Experiment 1
This is an experiment on visual perception. A fixation figure with 'fence' form
will be first presented at the centre of the screen for about 1 second. After the
fixation figure disappears, two Chinese characters will be simultaneously presented at
the left and ride sides of the figure respectively. After the presentation, a mask
consisting of random dots will cover the Chinese characters immediately. You are
asked to determine whether the two Chinese characters are exactly the same character.
If identical, please use your left/right thumb to press the button '1' and if not, please
use your another thumb to press '4' button on the 4-key board. You are also required
to respond to what the first comes to your mind as quickly and as correctly as possible.
If you cannot clearly identify the characters, you can give a decision based on your
own judgement but be sure you do not miss any response. And now you will be given
a series of practice trials. (Translation from Chinese)
123
3ic ̂ ^ . 1 ^ Hi it—
^ ± ^ s i n i o tmmm, im« 1 " m>, *nn*iw!, im « 4 "
^ ^ H 7 M ^ ^ i ^ p ] - f g . l E l i i t k f f l m - - ^ f : # i ± l ^ S J S o # ^ M ^ t M $ P J , H i t
124
Instructions in Experiment 2
This is a lexical decision test. A fixation figure with 'fence' form will be first
presented at the centre of the screen for about 1 second. After the fixation figure
disappears, two characters will be presented one followed another without break at the
same place of fixation figure. After the presentation, a mask consisting of random
dots will cover the Chinese characters immediately. You are asked to determine
whether the second presented character is a real Chinese character or not. If it is,
please use your left/right thumb to press the button ' 1' and if not, please use your
another thumb to press '4' button on the 4-key board. You are also required to
respond to what the first comes to your mind as quickly and as correctly as possible.
If you cannot clearly identify the characters, you can give a decision based on your
own judgement but be sure you do not miss any response. And now you will be given
a series of practice trials to understand what are called real Chinese characters and
pseudo-characters. (Translation from Chinese)
125
f4.'jN'f ;] :^^jn» i t |W|—'fiS^#—Itl— RtJs
$ & • — t Iii fft 51 o ® Iff % - Hk iti W&
, i ; ^^ f i<J^ , £fl "2j"> ifn " A " ¥•, M ^ * ^ o *
" 1 " f t . " 4 " i .
m&im
mm -*m>u
126
Instructions in Experiment 3a-d
This is a lexical decision test. A fixation figure with 'fence' form will be first
presented at the centre of the screen for about 1 second. After the fixation figure
disappears, one character will be presented at the same place of fixation figure. After
the presentation, a mask consisting of random dots will cover the Chinese characters
immediately. You are asked to determine whether the presented character is a real
Chinese character or not. If it is, please use your left/right thumb to press the button
'1' and if not, please use your another thumb to press '4' button on the 4-key board.
You are also required to respond to what the first comes to your mind as quickly and
as correctly as possible. If you cannot clearly identify the characters, you can give a
decision based on your own judgement but be sure you do not miss any response. And
now you will be given a series of practice trials to understand what are called real
Chinese characters and pseudo-characters. (Translation from Chinese)
127
(1-4)
i i M - t f i A . u . j , [ ^ j n ^ f # o r *
{ju^hivfo :m i # j g i i ^ n m ^ ,
- 1 bi 11 -ii in & t m m is b si o m m i % r % m
m m " * ' ] " , i w a x n ^ , % ^ \ m u 1 "
1 , Wi'MiU " 4 " Mo
& & & f i^v f ' i t i nx iu r f i i j , m&imjnm-m&
128
Instructions in Experiment 4
This is an experiment on visual perception through an EEG scanner, which will
take about one hour. During your rest, we will assist you to put on an electrode cap
with some gel. The installation of the caps and the following scanning are proved to
be safe to humans. Do you agree to participate in this and the next experiments? If
yes, please sign the consent form. Thank you.
A fixation figure with 'fence' form will be first presented at the centre of the
screen for about 1 second. After the fixation figure disappears, two Chinese
characters will be simultaneously presented at the left and ride sides of the figure
respectively. After the presentation, a mask consisting of random dots will cover the
Chinese characters immediately. You are asked to determine whether the two
Chinese characters are exactly the same character. If identical, please use your
left/right thumb to press the button ' 1' and if not, please use your another thumb to
press '4' button on the 4-key board. You are also required to respond to what first
comes to your mind as quickly and as correctly as possible. If you cannot clearly
identify the characters, you can give a decision based on your own judgement but be
sure you do not miss any response. Before you give your response, please try your
best not to move your head and eyes. In the absence of stimuli, you can slightly blink.
And now you will be given a series of practice trials to adapt the tests. (Translation
from Chinese)
129
W££o ^ - ^ i 5 M ; t # J n ^ - ^ M o tmM, i m
jm" i " M; « ; m im" 4 " tt=
^ W M l M I t , ^ r T « , {Si*
^ ^ i p s j t A A o
130
Instructions in Experiment 5
I his is a target searching test through an EEG scanner. The whole experiment
will take about one hour. During the preparation for the experiment, we will equip
an electrode cap with some gel.
The experiment consists of two parts. We will first conduct Part 1. Ten
Chinese characters are selected as stimuli, i.e., iii, H, 3 )̂ ifir, I t
and among which tfe and ^ are target stimuli and other eight characters are
standard stimuli. A cross is presented at the centre of screen to check fixation before
the test. The disappearance of the cross primes the test. If targets presented, you are
asked to press ' 1' with your left/right thumb and if standards presented, please press
'4' with another thumb, as quickly and as correctly as possible. If you cannot clearly
identify the characters, you can give a decision based on your own judgement but be
sure you do not miss any response. Before you give your response, please try your
best not to move your head and eyes. After you make a response and before the next
trail starts, you can slightly blink. And now you will be given a series of practice
trials to adapt the tests.
Part 2 is the same as in Part 1 except the stimuli. The stimuli are WM, %
$L, H, M and M, among which Sp and M are target stimuli and other
eight characters are standard stimuli. (Translation from Chinese)
131
•Ai. - t - f j f € B t A ^ 1 '>0to
mi ^ & ' i • •^ r^ $ i i ^ bj ft
Aft- ^ N mmm, i t &
? J o
^ ""I " & ' j< f t . M^J l MM£IW~&a
wii#ini'/'h 't'w(mTw.¥, gp.- n u ^ ^ mm\
mi»m&nmi i s m e w ? ^ "&" m "m», u i " n 5
i t f f l £ H S J t & " 4 " ® .
&RTEBI,
iL> ^ ^ ^ SN ^ f P f T ' o " S "
, <Hi i 1 f f i&$&!&$[&&&o &&&&&&]8M^MBBIBt^
30» ^ W M i f t f i l l t , ^ n j M , { f i i f ^ ' P I ^ A A o
— ^ 3 3 .
132
APPENDIX I
32-Chaimel Electrode Montage
©
0 ©
0 © Ml
© ©
© R ©
133
APPENDIX J1
Mean latency and amplitude of positive waves (40-80 Experiment 4 (n=37)
Electrode Latency Spot Diff Equ t p Diff
ms) across the scalp in
Amplitude Equ
Anterior Frontal Lobe
Fpl
Fp2 F7
F3
Fz
F4
F8
65.89+14.40
65.95+13.85
63.51 + 13.88
59.19+14.18
58.00+14.78
59.51 + 14.83
67.40+13.48
Left Temporal Lobe
64.54+13.17
60.16 + 13.19
60.65 + 12.61
61.41 + 10.61
58.59+12.83
60.54+ 9.91
Ft7
Fc3
T7
C3
Tp7
Cp3
Central Area
Fez 58.43 + 12.39
Cz 61.19± 10.74
Cpz 63.30+ 9.96
Right Temporal Lobe
Fc4
Ft8
C4
T8
Cp4
Tp8
55.08 + 11.77
63.41 + 13.66
59.03+ 9.98
62.49 + 11.74
60.70+10.08
57.89+12.23
Parietal-Occipital Area
P7
P3
Pz
P4
P8
01
02
Oz
57.30+11.23
58.97± 12.92
62.70 ±10.98
60.81 ±11.32
59.62+12.64
61.57 ±12.90
62.11 ±12.84
63.35 ±11.62
65.78± 15.09 0.04 0.98 2.47±2.06 2.53+2.81 0.15 0.89
62.92 ±14.58 1.09 0.28 2.36 ± 2.70 2.45 ±2.48 0.24 0.81
66.32 ±15.45 0.88 0.39 1.89 ±1.91 2.43+3.05 1.26 0.22
61.30± 14.53 0.67 0.51 1.65 + 3.16 1.95±2.68 0.54 0.59
61.84± 16.64 1.36 0.18 1.05±2.22 1.46+2.34 1.10 0.28
61.19± 15.77 0.66 0.52 1.29± 1.82 1.42+2.19 0.33 0.74
62.49±15.20 1.75 0.09 2.07±2.14 2.01 ±3.23 0.13 0.90
63.46± 15.09 0.35 0.73 1.93 ±1.86 2.12±2.51 0.50 0.62
64.32 ± 13.41 1.62 0.11 1.23 ±2.12 1.14+1.85 0.27 0.79
64.81 + 12.94 1.85 0.07 1.34± 1.63 1.84±2.04 1.36 0.18
63.51 ±11.82 0.89 0.38 1.23 ±2.14 1.38±2.17 0.42 0.68
59.30± 12.55 0.25 0.80 1.08± 1.46 1.32± 1.74 0.88 0.38
60.76 ±11.46 0.14 0.89 1.19±2.01 1.53±2.73 0.86 0.40
60.49± 15.86 0.93 0.36 1.08±2.50 1.23±2.43 0.38 0.70
61.41 ±12.47 0.12 0.91 1.64±2.35 1.78±2.52 0.34 0.74
62.70 ±11.62 0.34 0.74 2.31+2.38 2.27±2.62 0.08 0.94
60.22± 14.51 1.94 0.06 1.10±2.05 1.39±2.20 0.75 0.46
63.14± 13.73 0.09 0.93 1.97±2.24 1.94±2.89 0.07 0.94
60.97 ±12.22 1.01 0.32 1.38+2.21 1.79±2.54 1.03 0.31
61.40± 12.73 0.47 0.64 0.71 ±2.03 2.02±2.67 0.71 0.49
61.24+11.28 0.25 0.81 1.68±2.08 2.13±2.63 1.23 0.23
63.19± 13.21 2.30 0.03 1.14± 1.82 1.51+2.44 1.16 0.25
58.54± 13.14 0.50 0.62 0.69±1.47 1.13 ±1.82 1.55 0.13
59.89± 13.52 0.62 0.54 1.09±3.02 2.06±3.55 2.14 0.04
63.19 ± 11.32 0.27 0.79 1.63 ±2.70 2.06±3.05 1.04 0.31
60.65 ±11.96 0.09 0.93 1.59±2.97 2.12±3.48 1.19 0.24
60.81 ±13.42 0.58 0.57 1.13±2.05 1.06±2.01 0.27 0.79
60.49± 13.57 0.61 0.54 0.25±1.62 0.49±1.87 1.10 0.28
61.62 ± 13.94 0.23 0.82 0.34± 1.61 0-51 ± 1.90 0.77 0.45
61.24± 13.53 1.12 0.27 0.17± 1.62 0.54 ±1.91 1.76 0.09
134
APPENDIX J2
Mean latency and amplitude of Experiment 4 (w=37)
negative waves (80-160 ms) across the scalp in
Electrode Spot Diff
Latency Equ t Diff
Amplitude Equ t_
Anterior Frontal Lobe
Fpl 96.32+18.43
Fp2 95.89± 16.30
F7 94.11 ±14.83
F3 98.27 ±17.25
Fz 100.11 ±16.85
F4 98.11 ±15.80
F8 100.00 ±17.76
Left Temporal Lobe
Ft7 95.24 ±15.11
Fc3 97.24 ±16.55
T7 100.22 ±19.98
C3 100.54 ±18.60
Tp7 103.73 ±19.68
Cp3 103.15 ±18.08
Central Area
Fez 101.24 ±18.36
Cz 105.68 ±19.24
Cpz 111.19± 17.41
Right Temporal Lobe
Fc4 99.41 ±14.93
Ft8 99.95 ±18.50
C4 99.35 ±15.49
T8 97.03± 17.21
Cp4 103.68 ±17.70
Tp8 100.43 ±14.80
Parietal-Occipital Area
P7 106.59± 19.35
P3 108.92 ±18.44
Pz 113.19± 14.26
P4 110.38 ±18.37
P8 104.16± 17.33
01 111 ,78 ±21 -77
02 112.59 ±20.14
Oz 114.59 ± 18.15
100.65± 19.41
101.78± 19.34
99.24± 19.80
100.92 ±17.23
103.35± 18.55
102.59± 18.50
97.14 ± 17.55
99.57±20.73
98.86± 16.66
99,61 ± 18.92
101.68± 19.58
102.05 ±20.05
105.24± 19.58
102.49 ±17.98
106.49 ±19.48
109.57± 18.89
99.19 ± 17.46
96.49 ±18.89
100.59 ±17.06
100.81 ± 17.16
102.92± 17.69
100.38± 16.54
108.54±22.06
110.54 ± 19.30
115.19± 15.69
111 .08 ±20.17
108.70± 19.92
112.86 ±21.41
118.05 ± 18.61
117.46 ± 18.84
1.10
1.84
1.27
0.72
1.19
1.63
0.85
1.15
0.60
0.17
0.40
0.50
0.88
0.46
0.27
0.76
0.08
1.10
0.42
1.12
0.27
0.09
0.88
0.68
0.44
0.35
1.33
0.38
1.45
1.15
0.28
0.07
0.21
0.47
0.24
0.11
0.40
0.26
0.55
0.87
0.69
0.62
0.38
0.65
0.79
0.45
0.94
0.28
0.68
0.27
0.79
0.99
0.39
0.50
0.66
0.73
0.19
0.70
0.16
0.26
0.54±2.39
0.24±3.03
0.19 ±2.50
- 2.27±4.84
-2.08 ±2.90
- 1.73 ±2.74
0.37±2.73
- 0.16±2.19 - 1.97 ±2.62
- 1.43 ±2.13
- 2.34±2.91
- 2.16 ±2.10 - 3.36 ±2.98
- 2.50±2.94
-2.47 ±2.93
- 3.04±3.33
- 2.18 ±2.62
-0.21 ±2.73
- 2.37±2.73
-1.34±2.36
-2.93 ±2.79
- 2.24±2.15
- 3.57±2.62
- 5.16 ±4.62
- 5.49 ±4.19
- 4.12±3.96
-2.73 ±2.88
- 3.15 ±2.39
-3.06 ±2.29
- 3.56 ±2.73
0.19 ± 3.47
-0.20 ±3.00
0.57±3.60
- 1.60 ±2.80
- 1.98±2.94
- 1.69 ±2.82
- 0.17±3.83
-0.01 ±3.24
-1.75 ±2.60
-1.12 ±2.50
-1.97 ±2.68
-2.18 + 1.96
-3.17±3.10
-2.36 ±2.75
-2.26 ±2.84
-3.04±3.32
-2.12±2.63
-0.67±3.60
-2.22 ±2.80
-1.57 ± 3.31
-2.69 ±3.13
-2.68±2.41
-3.48 ±3.07
-4.76 ±5.34
-5.00±4.55
-4.01 ±4.88
-3.17±2.76
-3.22 ±2.97
-3.24 ±2.81
-3.52±3.20
0.88
1.00
0.71
0.76
0.26
0.13
0.99
0.35
0.67
0.97
1.06
0.14
0.58
0.37
0.60
0.01
0.18
0.97
0.45
0.53
0.60
1.36
0.38
0.89
1.09
0.24
1.80
0.27
0.80
0.19
0.38
0.33
0.48
0.46
0.79
0.90
0.33
0.73
0.51
0.34
0.30
0.89
0.56
0.72
0.55
0.99
0.86
0.34
0.66
0.60
0.55
0.18
0.71
038
0.28
0.81
0,08
0.79
0.43
0.85
135
Electrode Spot Sym
Amplitude Asym t P Sym
Latency Asym t p
Anterior Frontal Lobe Fpl -1.23 ± 1.72 -1.24 ± 2.96 0.03 0.98 105.87± 15.61 111 .20 ± 15.62 2.01 0.05 Fp2 -1.59 ±1.76 -1.51 ±2.49 0.19 0.85 106.20± 15.49 106.13 ± 13.62 0.02 0.98 F7 -1.52 ±1.11 -1.51 ± 1.26 0.06 0.95 106.07± 15.62 109.53 ±14.08 1.20 0.24 F3 -1.78± 1.88 -2.50±3.60 0.93 0.36 107.33 ±14.23 110.30± 14.05 1.01 0.32 Fz -2.16 ±1.98 -2.23 ±2.67 0.15 0.88 108.93 ±15.68 107.27 ±14.91 0.52 0.61
F4 -1.82± 1.78 -2.10 ± 2.17 0.66 0.52 106.73 ± 15.14 106.07± 15.16 0.20 0.84
F8 -1.46 ± 1.31 -1.49 ± 1.79 0.08 0.94 103.20± 16.28 103.87± 14.24 0.26 0.80
Left Temporal Lobe Ft7 -1.77+1.11 -1.74± 1.25 0.08 0.93 105.67± 15.54 107.40± 15.71 0.53 0.60
Fc3 -1.85 ± 1.27 -1.94±1.60 0.27 0.79 100.87± 14.58 106.67 ± 16.38 1.54 0.13
T7 -1.71 ±0.79 -1.97 ± 2.01 0.64 0.53 103.33 ±13.34 107.93 ±15.18 1.62 0.12
C3 -1.78 ± 1.21 -1.59 ± 1.76 0.56 0.58 96.53 ±14.90 97.67± 14.33 0.28 0.78
Tp7 -1.55 ± 0.82 -1.51 ± 1.27 0.15 0.86 98.55 ±16.26 103.87 ±18.75 1.37 0.18
Cp3 -1.47 ± 1.02 -1.35 ± 1.77 0.40 0.69 97.47 ±16.58 97.60± 18.78 0.03 0.98
Central Area Fez -2.64+1.96 -2.79 ±2.28 0.39 0.70 102.47 ±15.49 104.73 ±16.50 0.61 0.55
Cz -2.27± 1.68 -2.26 ±2.45 0.02 0.98 98.53 ± 15.51 98.87± 14.53 0.09 0.93
Cpz -1.61 ±1.31 -1.68±2.32 0.19 0.85 97.93 ±15.22 94.27± 14.33 1.07 0.29
Right Temporal Lobe Fc4 -2.11 + 1.56 -2.27 ±1.96 0.40 0.69 102.53 ±15.77 100.60± 13.46 0.61 0.55
Ft8 -1.60± 1.30 -1.82 ±1.31 0.75 0.46 105.93 ±15.59 101.07± 12.03 1.56 0.13
C4 -1.88 ± 1.60 -1.64 ±2.90 0.43 0.67 98.40 ±15.65 98.27 ±16.54 0.04 0.97
T8 -1.73 ± 1.13 -1.77 ± 1.53 0.15 0.88 102.87 ±17.78 99.07 ±15.72 0.87 0.39
Cp4 -1.23 + 1.22 -1.05 ±2.14 0.41 0.69 92.07 ±16.55 94.47 ±17.01 0.79 0.44
Tp8 -1.28 ±1-16 -1.67 ± 1.26 1.55 0.13 104.53 ±21.17 93.13 ± 19.80 1.43 0.16
Parietal-Occipital Area P7 -1.31 + 1.05 -1.24 ±1.29 0.23 0.82 105.73 ±25.27 107.80 ±25.53 0.49 0.63
P3 -0.95 ±1.61 -0.93 ±2.60 0.04 0.97 99.07 ±21.85 100.20 ±22.73 0.28 0.78
Pz -1.35 ±1.32 -1.11 ±2.18 0.49 0.64 94.00 ±16.02 99.00± 19.51 1.25 0.22
APPENDIX J3
r targets across the scalp in Experiment 5 (n=3Q)
t Sym Latency Asym t
Fc3
T7
C3
Tp7
Cp3
-1.85± 1.27
-1.71+0.79
-1.78+1.21
-1.55 + 0.82
-1.47+ 1.02
Central Area Fez -2.64+1.96
-2.27± 1.68
-1.61 + 1.31
Cz
Cpz
Right Temporal Lobe Fc4 -2.11 + 1.56
Ft8 -1.60+1.30
C4 -1.88+1.60
T8 -1.73 + 1.13
Cp4 -1.23 + 1.22
Tp8 -1.28 + 1.16
Parietal-Occipital Area -1.31 + 1.05 P7
P3
Pz
P4
P8
01
02
Oz
-0.95 + 1.61
-1.35 + 1.32
-0.73 + 1.61
-1.19 + 1.50
-1.62+1.43
-1.66 + 1.55
-1.61 + 1.58
-1.94+1.60
-1.97+2.01
-1.59+1.76
-1.51 ± 1.27
-1.35 ± 1.77
-2.79 + 2.28
-2.26 + 2.45
-1.68 + 2.32
-2.27+1.96
-1.82+1.31
-1.64 + 2.90
-1,77+1.53
-1.05+2.14
-1.67 + 1.26
-1.24 + 1.29
-0.93+2.60
-1.11+2.18
-0.62+2.74
-0.73 + 1.38
-1.40+2.30
-1.40 + 2.24
-1.63 + 2.07
0.03
0.19
0.06
0.93
0.15
0.66
0.08
0.08
0.27
0.64
0.56
0.15
0.40
0.39
0.02
0.19
0.40
0.75
0.43
0.15
0.41
1.55
0.23
0.04
0.49
0.20
1.57
0.47
0.55
0.05
0.98
0.85
0.95
0.36
0.88
0.52
0.94
0.93
0.79
0.53
0.58
0.86
0.69
0.70
0.98
0.85
0.69
0.46
0.67
0.88
0.69
0.13
0.82
0.97
0.64
0.84
0.13
0.65
0.59
0.96
105.87 + 15.61
106.20+15.49
106.07+15.62
107.33 + 14.23
108.93 + 15.68
106.73 + 15.14
103.20+16.28
105.67 + 15.54
100.87+14.58
103.33 + 13.34
96.53 + 14.90
98.55 + 16.26
97,47+16.58
102.47+15.49
98.53 + 15.51
97.93 + 15.22
102.53 ±15.77
105.93 + 15.59
98.40+15.65
102.87+17.78
92.07+16.55
104.53+21.17
105.73+25.27
99.07+21.85
94.00+16.02
101.93 + 24.94
110.87 + 27.30
124.87+22.33
124.80+21.56
124.73+21.93
111.20 + 15.62
106.13 + 13.62
109.53 + 14.08
110.30 + 14.05
107.27+14.91
106.07+15.16
103.87 + 14.24
107.40+15.71
106.67+16.38
107.93 + 15.18
97.67 + 14.33
103.87 + 18.75
97.60 + 18.78
104.73 + 16.50
98.87 + 14.53
94.27+14.33
100.60+13.46
101.07+12.03
98.27 + 16.54
99.07 + 15.72
94.47+17.01
93.13 + 19.80
107.80+25.53
100.20+22.73
99.00+19.51
101.40 + 23.76
112.67 + 25.40
118.87+23.65
115.87 + 24.06
118.67+23.07
2.01
0.02
1.20
1.01
0.52
0.20
0.26
0.53
1.54
1.62
0.28
1.37
0.03
0.61
0.09
1.07
0.61
1.56
0.04
0.87
0.79
1.43
0.49
0.28
1.25
0.13
0.41
1.45
1.89
1.41
0.05
0.98
0.24
0.32
0.61
0.84
0.80
0.60
0.13
0.12
0.78
0.18
0.98
0.55
0.93
0.29
0.55
0.13
0.97
0.39
0.44
0.16
0.63
0.78
0.22
0.85
0.69
0.16
0.07
0.17
136
t P Sym
1.69 0.10 196.47 ±34.52 1.33 0.19 193.20 ± 33.24 2.59 0.02 185.13 ±23.54 2.26 0.03 184.46 ±24.99 1.96 0.06 184.33 ± 21.01 2.48 0.02 187.00±23.96 1.28 0.21 183.40 ±23.82
2.45 0.02 187.00 ±25,30 3.21 0.01 183.73 ±21.93 1.47 0.15 187.80 ± 26.62 1.98 0.06 181.67 ± 23.34 0.01 0.99 196.60 ±40.23 0.25 0.81 190.87 ±29.43
APPENDIX J4 amplitude of P2 for targets across the scalp in Experiment 5
Fpl Fp2 F7 F3 Fz F4 F8
P7 P3 Pz P4 P8 01 02 Oz
Amplitude Asym t Sym Asym
Latency
10.41 ±3.09 10.01 ±2.99 8.92 ±2.44
10.70 ±3.35 11.27 ±3.77 10.66 ±3.57 9.16 ±2.81
Left Temporal Lobe Ft7 7.65 ±2.19 Fc3 10.07 ±3.16 T7 5.65 ±2.02 C3 8.06±2.75 Tp7 2.70 ±1.79 Cp3 5.84±2.12
Central Area Fez 10.91 ±3.82 Cz 10.22 ±3.32 Cpz 8.87±2.97
Right Temporal Lobe Fc4 9.90 ±3.31 Ft8 7.75 ±2.57 C4 8.15 ±3.17 T8 5.84 ±2.10 Cp4 6.33 ±2.79 Tp8 3.13 ± 2.20
Parietal-Occipital Area 0.55 ±1.79 3.66±2.70 5.92 ±2.70 4.32+3.92 1.00 ±2.62
- 0.26± 1.91 0.02 ±1.96 0.01 ±2.10
9.41 ±3.90 9.47 ±3.22 8.06±2.73 9.66 ± 2.83
10.63 ±3.44 9.91 ±3.07 8.73 ±2.69
6.93 ±2.58 9.29 ±2.83 4.92±3.04 7.59±2.84 2.70 ±1.74 5.75 ±2.74
10.11 ±3.22 9.74±3.51 8.58 ±3.33
9.18 ±3.16 7.18 ±2.39 8.27±4.07 5.71 ±2.31 6.71 ±3.55 3.36 ±2.01
1.55 ±1.99 4.63 ±3.80 6.53 ±3.14 5.40 ±4.75 2.09±2.59 0.65 ±3.07 0.80±2.92 0.29±2.61
1.69 1.33 2.59 2.26
1.96 2.48 1.28
2.45 3.21 1.47 1.98 0.01
0.25
2.85 1.39 0.71
2.43 1.85 0.23 0.47 0.74 0.83
3.71 1.75 1.34 1.68
3.41 1.60
1.61 0.69
0.10 0.19 0.02 0.03 0.06 0.02
0.21
0.02 0.01
0.15 0.06 0.99 0.81
0.01
0.17 0.49
0.02 0.07 0.82
0.64 0.46 0.42
0.01 0.09 0.19 0.10
0.01 0.12 0.12 0.50
196.47 ±34.52 193.20 ±33.24 185.13 ±23.54 184.46 ±24.99 184.33 ±21.01 187.00±23.96 183.40 ±23.82
187.00 ±25,30 183.73 ±21.93 187.80 ± 26.62 181.67 ± 23.34 196.60 ±40.23 190.87 ±29.43
183.07 ± 21.53 183.67±24.80 182.80 ±29.00
188.40 ±25.77 184.33 ±26.43 190.00±29.82 191.07±33.18 203.20±38.35 218.20±43.43
179.60 ±47.59 204.33 ±48.01 204.07±44.60 220.40 ±44.47 230.40±49.35 201.13 ± 50.41 212.27±47.84 201.87 ±49.18
190.40 ±31.52 190.53 ±31.05 185.13 ±25.24 187.46 ±27.40 185.80 ±24.85 190.33 ±29.54 188.13 ± 27.73
188.27 ±30.90 183.40 ±21.20 191.60 ±33.66 197.53 ±40.13 199.66 ±47.24 203.53 ±42.31
185.33 ±23.53 191.00 ±34.20 198.13 ±43.46
189.80+28.14 184.20 ±22.59 196.20 ±37.47 201.67 ±39.21 208.07±46.01 221.07±48.66
198.47 ±53.05 214.27±49.13 203.60±49.30 218.80 ±47.85 217.27 ±50.40 191.13 ±52.23 208.93 ±45.63 204.93 ±50.50
0.92 0.41 0.00 0.89 0.62 0.77 0.99
0.37 0.69 1.00 0.38 0.54 0.45 0.33
0.21 0.84 0.22 0.83 0.85 0.41 2.18 0.03 0.39 0.70 1.59 0.12
0.97 0.34 1.52 0.14 2.56 0.02
0.31 0.04 1.23 1.43 0.72 0.36
2.22
1.15 0.07 0.21 1.16
1.15 0.37 0.33
0.76 0.97 0.23 0.16 0.48 0.72
0.04 0.26 0.95 0.83 0.26 0.26 0.72 0.74
137
Mean latency and («=30)
APPENDIX J5 amplitude of N2 for targets across the scalp in Experiment 5
Symm Amplitude Asym t
Latency Sym Asym t p
Anterior Frontal Lobe 0.43+4.33 0.05+4.49
-0.67 + 3.30 - 1.35+4.16 -2,65+4.75 - 1.10+4.28 -0.36 + 3.40
Left Temporal Lobe Ft7 -0.98 + 2.58
- 1.21+3.52 - 1.32+2.35 -0.73 + 3.15 - 1.72+1.58 -0.49 ±2.65
Central Area Fez - 2.50±4.90 Cz -0.70 ±4.42 Cpz 0.29 ±3.87
Right Temporal Lobe Fc4 - 1.06 ±3.88 Ft8 -0.69 ±2.69
-0.35 ±3.74 -0.93 ±2.04 0.16 ±2.86
- 1.28 ±2.34
Fpl Fp2 F7 F3 Fz F4 F8
Fc3 T7 C3 Tp7 Cp3
C4 T8 Cp4 Tp8
Parietal-Occipital Area P7 P3 Pz P4 P8 01 02 Oz
- 3.84±2.14 - 1.73 ±2.79 -0.74+2.42 - 1.15 ±2.68 -2.93 ±2.60 -3.46 ±2.03 -3.04 ±2.23 - 3.00±2.23
- 0.47±5.37 - 0.06±4.44 - 0.96±3.71 - 2.37±4.61 -2.44 ±4.85 - 1.25 ±3.89 0.20±3,36
-1.15±2.86 -1.10 ± 3.61 -1.78 ±3.23 - 0.69 ± 3.31 - 2.26±2.30 -0.71 ±3.27
-2.77 ±4.93 - 1.08 ±4.84 -0.55 ±4.29
- 0.95±3.75 -0,23 ±2.54 0.05 ±4.61
-0.59 ±2.63 0.32±3.70
- 1.40 ± 1.76
- 4.17±2.43 - 1.69 ± 3.73 -0.94±3.85 - 0.78±3.92 -2.62 + 2.54 - 3.37±2.66 - 2.63±2.58 -2.91 ±2.44
0.96 0.17 0.53 1.22
0.47 0.26
1.26
0.41 0.24 0.78 0.10
1.54 0.56
0.56 0.80 1.76
0.24 1.24 0.68
0.90 0.27 0.40
0.86 0.06 0.36 0.52 0.82 0.20 0,95 0.24
0.38 0.85 0.60 0.23 0,64 0.80 0.22
0.23 0.50 0.37 0.79 0.69
0.40 0.95 0.73 0.60 0.42 0.88 0.35 0.81
342.40 ±36.58 340.33 ±40.73 323.40±29.27 312.54±21.91 311.47 ±21.83 313.00±22.00 320.80 ±35.32
335.20 ±53.76 333.33+53.79 319.93 ±47.71 325.00 ±29.72 315.93 ±32.19 319.80 ±38.19 318.87 ±50.23
0.74 0.62
0.44 2.02
0.69 0.92 0.42
0.46 0.54 0.66
0.04 0.50 0.37 0.68
0.69 319.20 ±25.97 325.47±40.92 0.92 0.37 0.81 0.44 0.92 0.14 0.58
0.58 0.43 0.09
306.33 ±26.79 315.93 ±31.56 305.60 ±27,64 304.00±41.73 294,33 ±37.48
3 04.20 ±21.22 300.33+24.93 291.87 ± 32.19
310.13 ±37.61 322.87±35.9 5 305.87 ±37.23 299.80±48.28 294.00 ±44.74
307.87 ± 37.55 299.80 ±40.8 8 274.93 ±42.00
0.53 1.03 0.04 0.41 0.05
0.57 0.07 1.88
0.60 0.31 0.97 0.69 0.96
0.58 0.95 0.07
0.82 304.20±21.52 304.93 ±38.70 0.11 0.92 315.87+33.49 301.87 + 27.05 304.73 ±38.63 289.47 ±34.11 295.47 ±39.07
266.13 ±39.63 263.47±37.78 270,53 ±35,53 268.13 ±36.36 278.80±42.62 264.13 ±34,32 266.00±49.58 268.93 ±47.85
3 07.67 ±50.02 300.07±41.34 298.13 ±58.81 286.60±50.30 289.73 ±57,13
293.93 ±39.52 272.60 ±40,20 276.27±40.11 279.60±48.61 296,00 ±50.24 291.20 ±30.51 292.20 ±48.22 279.87±28.62
0.99 0.25 0.80 0.37 0.65
2.72 1.42 0.90 1.40 1.98 3.73 2.50 1.34
0.33 0.81 0.43 0.72 0.52
0.01 0.17 0,39 0.17 0.06 0.01 0.02 0.19
138
Mean latency and (»=30)
APPENDIX J6 amplitude of P3 for targets across the scalp in Experiment 5
Symni Amplitude Asym
Anterior Frontal Lobe Fpl 6.86±4.44 Fp2 7.16 ±4.64 F7 7.06 ±3.93 F3 12.27 ±5.04 Fz 14.62 ±5.03 F4 12.63 ±5.14 F8 7.65 ±3.75
Left Temporal Lobe Ft7 7.83 ±3.29 Fc3 14.69 ±4.60 T7 8.79±3.03 C3 15.62 ±4.45 Tp7 7.79 ±2.71 Cp3 15.37 ±4.05
Central Area Fez 17.53 ±5.54 Cz 19.18 ±5.47 Cpz 19.16 ±4.94
Right Temporal Lobe Fc4 15.15 ±5.24 Ft8 8.03 ±3.34 C4 15.72 ±4.91 T8 8.69 ±3.14 Cp4 15.10 ±4.26 Tp8 8.39 ±3.18
Parietal_Occipital Area P7 5.66 ±2.40 P3 12.71 ±3.70 Pz 15.48 ±4.49 P4 12.57 ±4.24 P8 5.70±2.87 01 3.17 ± 2.17 02 3.16 ±2.38 Oz 3.50±2.48
Latency Sym Asym t p
7.11 ±4.15 0.27 7.51 ±3.11 0.61 6.94±3.78 0.18
11.28 ±4.60 1.04 14.41 ±4.90 0.31 11.98 ±4.07 0.93 7.79 ±2.77 0.34
7.44±3.67 14.24 ±4.73 8.24±3.47
15.12±4.43 7.39 ±2.91
14.90 ±4.73
16.82 ±5,54 18.17 ±5.60 18.01 ±5.51
14.40 ± 5.01 7.70±2.30
15.22 ±5.33 8.27±2.64
14.63 ±4.85 7.86 ± 2.35
5.86±2.82 12.97 ±5.09 15.07 ±5.53 12.74±5.20 6.10 ±2.64 3.23 ±2.58 3.55 ±2.57 3.63 ±2.54
0.74 0.83 1 . 1 1 0.96 1.26
0.80
1.01 1.50 1.83
1.14 0.77 0.78 1.04 0.81
1.64
0.74 0.38 0.67 0.26 1.42 0.88 0.98 0.33
0.79 0.55 0.86 0.31 0.76 0.36 0.74
0.47 0.41 0.27 0.35 0.22 0.43
0.32 0.15 0.08
0.26
0.45 0.44 0.31 0.42 0.11
0.47 0.71 0.51 0.80 0.17 0.39 0.34 0.75
409.53 ±81.89 408.47± 80.91 468.20 ±45.11 456.46±40.96 447.60 ±40.06 450.20 ±40.35 445.47 ±59.99
467.53 ±41.05 459.27±37.84 472.00 ±35.91 467.40±29.52 471.87 ±35.80 469.53 ±30.17
454.00 ±38.40 458.80±36.54 465.33 ±29.77
459.87±39.24 465.87±40.27 463.20 ±31.75 471.47 ± 35.96 466.60±30.39 462.47 ±34.93
471.40 ± 36.59 470.13 ±32.73 462.93 ±32.27 462.00 ±31.74 456.93 ±39.15 459.47±42,30 449.53 ±47.12 460.67±46.06
388.67 ± 80.83 397.80±73.36 455.27±66.85 462.69±50.84 456.00±43.31 457.73 ±42.43 451.86 ±68.94
480.33 ±40.31 460.27±39.82 475.47 ±39.12 472.53 ±34.14 468.07 ±32.84 467.40 ±31.58
457.53 ±40.66 465.87±41.14 474.00 ±40.13
463.00±44.68 460.67±66.83 465.00±40.59 463.87±49.96 462.73 ±34.37 457.60 ±52.20
465.00±31.79 457.40±35.33 461.33 ±31.91 453.00 ±29.04 453.60±37.92 451.80 ±44.42 440.93 ±48.27 451.00 ±47.09
1.38 0.90 1.26 0.57 1.14 0.90 0.63
0.17 0.51 0.97 0.59 0.41
0.61 1.25 1.43
0.44 0.42 0.28 0.71 0.62 0.47
0.93 1.98 0.31 1.68
0.46 0.80
1.08 1.09
0.18
0.38 0.22
0.58 0.26 0.38 0.54
0.10
0.86 0.62 0.34 0.56 0.68
0.55 0.22
0.16
0.66 0.68
0.78 0.49 0.54 0.64
0.36 0.06
0.76 0.10 0.65 0.43 0.29 0.28
139
Mean latency and 5 (n=37)
APPENDIX J7 amplitude o fNl for standards across the scalp in Experiment
Anterior Frontal Lobe Fpl -1.09+1.56 Fp2 -1.03 + 1.60 F7 -0.95 + 1.82 F3 -1.60+1.53 Fz -2.24+1.87 F4 -1.70+1.60 F8 -0.82+1.65
Left Temporal Lobe Ft7 -1.23 + 1.29 Fc3 -1.85 + 1.43 T7 -1.26+1.06 C3 -1.66± 1.37 Tp7 -1.67+1.30 Cp3 -1.31+1.27
Central Area Fez -2.70+1.97 Cz -2.25 + 1.79 Cpz -1.51 ±1.59
Right Temporal Lobe Fc4 -1.95 + 1.36 Ft8 -0.90+1.69 C4 -1.70+1.31 T8 -1.14+1.56 Cp4 -1.29+1.35 Tp8 -1.51 + 1.42
Parietal-Occipital Area P7 -4.45 ±2.67 P3 -1.97 ±2.29 Pz -1.11 ±1.49 P4 -2.27 ±2.43 P8 -4.27±2.81 01 -3.28+1.81 02 -3.18± 1.99 Oz -2.87 ±2.09
Amplitude Latency Symm Asym t p Sym Asym t_
-1 -09± 1.90 -1.41 ±2.06 -0.93 + 1.62 -1.60 ±2.27 -2.37 ± 1.85 -1.84± 1.74 -0.96 ±1.62
-1.21 ±1.29 -1.75 ±1.49 -1.27 ± 1.21 -1.47 ± 1.38 -1.59 ± 1.44 -1.19 ± 1.29
-2.71 ±2.04 -2.13 ±1.79 -1.37 ± 1.53
-1.92± 1.45 -1.13 ± 1.45 -1.56 ± 1.41 -1.29± 1.39 -1.14± 1.41
0.03 1.70 0.14 0.00 0.67 0.88
0.60
0.14 0.52 0.07 1.07 0.55 0.73
0.05 0.60 0.74
0.18
1.18 0.72 0.88
0.70
0.98 0.10
0.89 1.00 0.51 0.39 0.56
0.89 0.61
0.95 0.29 0.59 0.47
0.96 0.56 0.47
0.86
0.24 0.48 0.39 0.49
108.54± 14.98 107.57± 13.45 107.35 ± 12.25 105.46± 12.49 107.08 ±14.22 105.84± 13.16 104.65 ±14.49
105.89 ±12.73 104.49 ±12.09 105.24 ±21.96 98.70± 13.03
129.84±41.82 101.41 ±26.93
105.19± 14.16 99.62 ±12.28 97.83 ±21.38
102.70± 14.86 102.92± 13.74 101.57 ±21.83 102.49+21.25 104.97±32.84
107.84+14.00 108.22± 13.50 106.81 ±13.80 110.11 ±15.22 109.35 ±14.25 109.51 ±14.50 105.56± 12.13
105.46 + 14.44 106.43 ±13.96 109.03 ±21.13 102.76 ±14.46 128.11 ±37.92 108.76 ±26.94
107.57 ±14.29 101.14± 12.21 99.14+11.38
105.51 + 13.89 101.89 ±13.10 99.03 ±11.95
102.81 ±13.80 106.38 ±30.41
0.30 0.40 0.29 2.55 1.10
1.85 0.54
0.19 1.02 0.87 1.36 0.47 1.46
1.13 0.85 0.33
1.40 0.73 0.73 0.10 0.32
-4.85 ±2.59 -2.09 + 2.49 -1.03 ±1.49 -1.96±2.62 -4.55 ±2.95 -3.57 ±1.76 -3.04±2.50 -2.70±3.10
3.04 0.60
0.55 1.26 1.46 1.47 0.48 0.42
0.01 0.56 0.59 0.22 0.15 0.15 0.63 0.68
166.05 ±22.92 144.81 ±42.35 114.05 ±41.82 148.86 ±41.01 169.67± 18.92 168.92+16.96 169.68± 15.36 167.30 ±18.20
165.78+21.70 143.41 ±38.01 109.46 ±33.25 152.16 ±37.35 170.76 ±17.27 167.95 ±13.56 165.41 ±18.42 166.43 ± 15.52
0.76 0.69 0.78 0.02 0.28 0.07 0.60
0.85 0.32 0.39 0.18
0.64 0.15
0.26
0.40 0.75
0.17 0.47 0.47 0.92 0.75
-1.46 ± 1.27 0.27 0.79 138.22±39.93 123.08±39.15 2.00 0.05
0.22 0.26
0.79 0.64 0.30 0.50 1.09 0.48
0.83 0.80
0.44 0.53 0.77 0.62 0.28 0.64
140
1 5
APPENDIX J8 Mean latency and amplitude of P2 for standards across the scalp in Experiment 5 («=37)
Symm Anterior 1
Fpl
Fp2
F7
F3
Fz
F4
F8
:rontal Lobe
8.03 ±2.63 7.99 + 2.77 7.38 + 2.22 8.62 ±2.54 8.53 + 2.78 8.31 ±2.55 7.39 + 2.31
Left Temporal Lobe Ft7
Fc3 T7
C3
Tp7
Cp3
Fe4
FtS
C4
T8
Cp4
Tp8
7.64 ±2.39 6.34 ±2.17 6.23+2.39 4.46 ±1.75 4.91 + 1.96 2.25 + 1.22
F7 P3 Pz
P4
P8
01 02 Oz
0.91 ±1.52 3.79 ±2.35 4.99 ±2.14 3.83 ±2.94 1.62 ±1.92 0.25 ±1.51 0.57+1.83 0.37 ±1.72
Amplitude Asjap t_
6.11 ±2.08 7.67 ±2.44 4.34 ±1.83 5.99 ±2.22 1.94 ±1.44 4.63 ±1.81
Central Area
Fez 8.19 ±2,84 Cz 7.62 ±2.68 Cpz 6.88 ±2.32
Right Temporal Lobe
Parietal-Occipital Area
8.83 ±2.96 8.46 ±3.10 8,05 ±2.29 9,68±3.14 9.64 ±3.09 9.37±3.00 7.88±2.70
6.72 ±2.25 8.74±2.65 4.93 ±2.03 6.98 ±2.58 2.32 ±1.79 5.13 + 2.12
9.41 ±3.17 8.88 ± 2.98 7.66 ±2.63
8.64±2.80 6.76 ±2.46 7.21 ±2.81 4.95 ±2.05 5.34 ±2.42 2.56 + 1.52
1.11 ± 1.48 3.66 ±2.63 4.98 ±2.33 3.94 ±3.31 1.73 ±2.19 0.46 ±1.91 0.99±2.52 0.79 ±3.16
Sym Asym Latency
t
3.31 1.49 3.54 3.61 4.82 4.67 1.64
3.90 4.97 3.48 4.89 1.99 2.97
4.71 5.79 3.34
4.64 1.38 4.33 2.39 1.69 1.61
1.04 0.50 0.05 0.41 0.43 1.09 1.50 1.16
0.01
0.15 0.01
0.01
0.01
0.01
0.11
0.01
0.01
0.01
0.01
0.05 0.01
0.01
0.01
0.01
0.01
0.18
0.01
0.02
0.10
0.12
0.30 0.62
0.96 0.68
0.67 0.28
0.14 0.26
185.30±23.32 182.97 ±21.68 182.11 ± 19.61 182.86± 19.50 182.86 ±19.25 183.95 ±19.38 183.84±22.07
183.73 ±23.89 182.76 ± 20.14 186.11 ±32.47 186.27 ±30.79 231.62 ±50.46 207.67 ±51.90
181.24± 18.59 180.32 ±20.32 195.89 ±43.65
187.24 ±24.22 180.65 ±22.23 199.14 ±40.80 184.97 ±27.55 216.65 ±51.39 231.62 ±50.47
232.11 ±55.33 227.51 ±51.11 213.67 ± 55-25 225.41 ±55.90 236.00 ± 54.18 217.89 ± 53.63 232.59 ±48.57 217.89 ± 52.60
183.03± 18.47 182.16± 17.36 184.22±20.36 183.46± 18.68 182.76 ±17.99 183.24± 18.13 183.89±20.54
184.60 ±22.42 182.65 ±18.45 188.97+29.46 186.16 ± 26.54 228.38±48.88 207.14 ±41.18
181.51 ±16.48 184.54 ± 23.17 190.00 ±31.86
184.54 ±20.29 185.30±23.91 188.22±28.44 188.81 ±29.69 206.65±43.75 228.37±48.88
222.22 + 60.48 227.95 ±47.88 203.62 ±44.59 223.84±49.20 235.89±54.17 218.43 ±56.43 222.97+52.25 220.38±54.88
0.70 0.37 0.82 0.28 0.06 0.36 0.03
0.28 0.06
1.05 0.03 1.40 0.06
0.21 1.47 1.24
0.75 1.63 2.08 0.76 1.75 0.48
1.14 0.06
1.28
0.24 0.02
0.06 1.43 0.35
0.49 0.71 0.42 0.78 0.96 0.72 0.98
0.78 0.95 0.30 0.98 0.17 0.95
0.84 0.15 0.23
0.46 0.11
0.05 0.45 0.09 0.64
0.26
0.95 0.21 0.81 0.99 0.95 0.16
0.73
141