PLATE TECTONICS: A STUDY OF TRANSMISSION OF IDEAS

ApplY1:ng bibl.iometx-io techniques on the dataanalysed from Science Citation Index for the years1968 to 1977, it was found that the Le Pichon's wellknown article published in 1968 in the Journal ofGeophysical Research proved 'infectious' and spreadthe new idea on sea-floor throughout the world. Thearticle received in all 593 citations during thisperiod and followed a well defined epidemic pattern,receiving maximum citations in the year 1970 andgetting slowly stabilized in the year 1974.

INTRODUCTION

Bibliographic studies of subject literatureshelp in organising the library and information re-source sand plann ing of more efficient and effectivelibrary and information services. Numerousstudies have been conducted applying one of thefollowing bibliometric techniques individually or incombination of one or two:

1. the Bradfard's technique of identifying themost productive journals, monographs,authors and publishers etc.

2. Price's technique for determining theresearch front of a subject by ana lys ingreferences cited in the journal articles;

3. the GoHman-Kessler bibliographic coupl-ing technique which provides a more logicalapproach to subject classification thandirect matching procedures; and

4. Goffman's model of literature growthwhich derives from the analogy between thespread of infectious diseases and thespread of ideas.

Donohue in his recent book has demonstratedthe application of all these techniques by analysingthe literature of information science [1]. Principalapp r ea ch used in this study for analysing the litera-ture of Geophysics is the epidemic theory of litera-ture growth as developed by Goffman [2]. The ideais derived from the analogy between the spread of

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D.K.GUPTALecturer, Dept. of Lib.Studies, Universityof lbadan, Ibadan,Ni~eria

infectious disease and the spread of ideas. Thereare well deve loped techniques for determining thesize of infection, nature of infection, the directionof infection and thus predicting the epidemics.Ideas can be spread from person to person directlyor indirectly by way of an intermediate host -through the literature. An idea has the potential forgrowth and reproduction. Certain ideas do followan epidemic process. They are held by isolatedindividuals fer a time, then become epidemic andfinally either become stabilized or decline. Goff-man [4] has applied epidemic theory to comprehen-sive bibliography of mast cell research.

An idea on Plate Tectonics in t he er et ic a l Geo-physics attracted the attention of the scientists ofthe world throughout, during late 1960s. A newidea was propounded by Le Pichon in 1968 whichrevolutionised the well established concept of centi-nental drift. The idea spread very fast throughoutthe world in all the directions and was perhapsexamined by all those numerous scientists whewere concerned with this kind of studies or studiesof s im ila r or re lated nature.

EPIDEMIC NATURE OF THE IDEA ON SEA-FLOORSPREADING:

The article entitled nSea-Floor spreading andContinental Drift" got published in the learned jour-nal of Geophysics - Journal of Geophysical ResearchVolume 73, issue 12; p3661-3697. The articlepublished by Xavier Le Pichon, drew the attentionof a large number of scientists which is quite ev i-d e nt from the sub se que nt publication of Ie tce r s toeditors. editorials. discussions. articles. andr evir w a rt icl e s on this topic c it ing this pap. r ,The citation data for this article and other articlesof Le Pichon is presented in Table No. 1, as reveal-ed in the Science Citation Inde x (1965-1977). Themain objective of this study was to examine the epi-demic nature of t h is idea of Plate Tectonics andSea-Floor Spreading:

1. by tracing out the original paper'o! LePichon which is supposed to be infectious;

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PLATE TECTONICS

2. by determining the nature of actual epi-demic i, e., the extent of the epidem ic interms of time and space; and

3. by finding out the current status of the epi-demic;.

CITATION ANALYSIS

Citation analysis technique was applied bymaking extensive use of Science Citation Index. Aswe know, the Index constitutes the largest citationdata base for all science and technology, providesa good opportunity to conduct such a study. Thedata on the citations received by all the articles ofLe Pichon. were collected by lookirig th r ough all t hevolumes of SeI available in the Un ive r s it y of IbadanLibrary and the Library of Inte r nat ion aI In st it ute ofTropical A~riculture. By l ooki ng up Le Pichon X inthe Citation Index sections of t he various volurne e.of SCI (cumulative Index. 1965-69. 1970-74. indi-vidual yEarly cnmulative volumes of 1975.1976 and1977), the d~ta on all the citations received by theauthor for all of his papers were collected. Thedata showing the number of articles published in aparticular year and cited during a specific year orperiod, the number of citations received by thesearticles etc. are presented in the Table No. 1. Forexample. Le Pichon'" 15 articles published in 1968were cited 115 times dur ing the period of J965-69.and, in all, his 35 articles published during 1960-69, received 166 citations.

The data were further analysed looking criti-cally again in the Citation Index volumes for theindividual articles for their citation patterns.Three of his articles were identified, receivingmaximum citations, consistently thr oug hout thisperiod. These ar t ic Ie s hav e been rna r ke d or labelledfor their identification and future reference asARTICLE ONE (marked as * in the table), ARTICLETWO (marked as ** in the tab le ] and AR TICLETHREE (marked as + in the table). The details ofthese articles are given as below:

ARTICLE ONE (*) was published in 1965, ARTICLETWO and AR TICLE THR EE were publ is hed in 1968.All the three articles were published in the periodi-cal, Journal of Geophysical Research. All thethree articles were looked again in SCI for theircitation patterns. The articles have been citedheavily by all kinds of documents such as, letters(L), Discussions (D), Editorials (E), Review arti-cles (R), Notes (N) etc. The data for these articlesis presented separately in Table No.2 indicatingthe details of number of citations received by themindividually for each year, and the kinds of pub l ica+tions received by them individually for each year,and the kinds of publications citing them. Theirstatus arrrong an the articlell of Le Pichon is indicat-oed by caI cul at ing the pe r c ent ag e e of their citationsand this data is presented in Table No 3. Lookinggenerally,' and as well as examining the data pre-sented in table No. 1,2, and 3, one can easily identi·

Vol 25 No 1-4 Mar-Dec 1978

fy that the article three (+) published in 1968 in theJournal of Geophysical Research (vol. 73) was mostheav ily cited. The refore, it was thought nece ssaryto ana lyse the c itat ion data of this article in moredeta il. Year to yea r citat ions for this art icle werecounted, kinds of various pub l icat ion s citing thearticle were noted. The analysis of this data ispresented in tab Ie No.4, 5,6.

INFECTIOUS IDEA

On ex am in ing the citation data presented int abl e I. one can notice that Le Pichon has publisheda large number of papers during the period of 1960-77. A- majority of his articles have been cited bythe various authors in a variety of forms of litera-ture. All of his papers published during this yeriodreceived in all as many as 15J3 citation II. LePi-chon's fi r st article was of 1960 which was c it e d bya few authors and received c on s is tent citations evenupto 1977. Perhaps. Le Pichon did not publish an Y>thin~ in the years 1961. 1962. and J963. Even hispublication of 1964. was not v(ry much cited. all itr e ceived in all 4 citations with no citations dur-IngJ976 and 1977. But one of his articles of 1965(ARTICLE ONE) has been very consistently cited,receiving in all 65 citations upto 1977. This article"Crustal structure of the mid-ocean ridge - 1. Seis-mic refraction measurement" by Lepichon, X andothers, published in the leading journal of geo-physics, Journal of Geophysical Research (vol. 70,issue No.2; p 319-339) is the first to generate theinterest in the author, his team and other scientiststo think and work in this new direction. This arti-cle can be said to be generic in its nature fordeveloping further ideas in the direction of newthinking, but could not be said as infectious. Othertwo articles are of 1968. Out of which one, articletwo(**) seems to be very important as evident fromthe citation pattern, indicating consistancy of cita-tions upt o 1977 and being cited as many as 122times, but cannot be classified as infectious if onecompa re s the citat ion pattern of the other publica-tion of 1968. ARTICLE THREE (+), "See-Floor

Spreading and Continental Driftft published in theJournal of Geophysical Research, Volume No. 73,issue No. 12, page 3661 -3697, which has receivedthe maximum citations, 593 out of 1513 of all thecitations L~ Pichon has r e ce ive d for all his publica-tions so far. The article thus rece iv ing 39.2'10 ofall the citations could be identified easily, contain-ing the most potential idea to become infectious.

EPIDEMIC NATURE OF INFECTIOUS IDEA

To further examine the nature of the infec-tious idea the data were analysed in detail, and theresults of the analysis are given in Tables No.4, 5,and 6. The citations for year to year from 1968 to1977 are given in Table No.4 and graphically repre-sented in the Fig. No. 1. The citation pattern veryclearly indicates the potential of the idea to becomeinfectious and which became highly infectious during

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TABLE I: CITATIONS RECEIVED BY LEPICHON DURING THE PERIOD1965-1977

Year of the Period during Period during Ye;;-d~-.:i~g--y-;; ~~-d,:;-rin-g--y.;ar-d-ur-irig-----T -ota I--

article s articles were articles were articles articles artic Ie s citationscited cited cited were cited were cited were cited---------------------

YEARS 1965 - 1969 1970 1974 1975 197b 1977

YEARS I II I II II II I II

1960 3 9 2 3 2 151961196219631964 1 1 1 2 1 I 41965 2* 25 2* 26 1* 3 1* 9 1* 2 651966 7 9 2 2 1 1 121967 2 2 3 4 1 1 71968 15+ 115 27+** 560 7+** 49 6+** 52 6+** 45+** 8211969 7 13 7 62 3 5 5 8 2 5 931970 12 30 2 3 2 3 5 7 421971 30 164 14 45 12 54 18 53 3161972 5 9 5 6 1 2 171973 1 4. 8 22 8 33 10 33 921974 4 14 2 2 3 3 1 1 201975 1 1 1 1 1 1 31976 2 2 2 2 41977 1 2 2

-----------------------------TOTAL 35 166 97 886 45 137 43 170 49 154 1513

I No. of articles cited during the year/periodII No. of citations received during the year/period

* ARTICLE CNE** ARTICLETWO

+ ARTlCLE THREE

TABLE 2: CITATION DATA FOR THREE MOST CITED ARTICLES

--------------------Articles 1965-69 1970-74 1975 1976 1977 Totalcited

ARTlCLE ONE (*) 24 25 3 9 4 65

J Gephys Res. IR; 3L lR IR 2R 5R;70(2); 319- ; 1965 3L

ARTICLE TWO{**) 35 74 3 4 6 1 22

J Gephys Res. IR; 9L 3R 3R IR IN 8R;

73; 2101- ; 1968 9LIN

ARTICLE THREE{+) 67 417 38 41 30 59313L; 4N 19R;5L; 7R 2R 3R;IL 31R;

2E; 3D; 19L;17N; 2E;3D

21N;

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TABLE 3: DISTRIBUTION OF CITATIONS AMONG VARIOUS ITEMS

Item No. of citations ~ Cum~-

Article one(*) 65 4.3 4.3.Article Two(**) 122 8. 1 12.4Article Three(+) 593 39.2 5 I. 6other items 733 48.4 100.00

-------Total 1513 100. a 100. a

TABLE 4: CITATIONS RECEIVED BY ARTICLE THREE

(published in Journal of Geophysical Research;Vol.73;rssue.No.12; p3661-3697; 1968)

Cumulative",1.Year during No. of

article is citationscited -=-re=-c=-e::.:i:.:v~e~d _

cumulation

593

01. 01 610.29 6718. 04 17417. 03 27515.85 36912. 31 442

7.08 4846.42 5226.91 5635. 06 593

100. 00 593

01.0111. 3029.3446.3762.2274.5481. 6288.0394.94

100.00

19681969'19701971197219731974197519761977

661

107101

947342384130

TOTAL 100.00

TABLE 5: FORMS OF PUBLICATIONS CITING ARTICLE THREE

Year of Articles Editorials Letters Discussions Notes Reviews Totalcitation A E L D N R T

1968 4 2 61969 46 11 4 611970 96 2 5 3 1071971 90 .2 3 5 1011972 80 2 7 4 941973 68 1 1 3 731.914 37 1 4 421975 31 7 381976 39 2 411977 26 3 30

TOTAL 517 2 19 3 21 31 593

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Table 6: PERCENTAGE DISTRIBUTION OF CITING ITEMS

No.------------------

1.Items

A rticles (A)Reviews (R)Notes (N)Letters (L)Discussions (D)Editor ia Is (E)

517312119

32

87. 35.23.53.3.5.3

TOTAL 593 100.00

110

t so

~400~~•...u 30t ,-,

I20'-

"

iOO

90

70

60

10

ClRAPH SHOWING 'l'HE

DISTRIBUTIOll OF CITATIONS

'!'BROUGH 'l'BE !EARS I90i:! - 17

II 72. 13 14-' i5' 7'01

TEARS~17

90

,0

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FORKS OF PUBLICATIONS

PIG. 2

t he years 1'1IU and 1971. During t he s e years, t hearticle was cited 107 and 101 times respectively,in a variety of documents originating from severalcountries. The idea, thus, had spread in all d ir ec :t ion s throughout the world, very quickly. The ide"got stabilized in the normal way, during the years1974. 1975, and 1976 having received an averageof 40 citations for these years (42. 38, and 41 res-pectively). It shows a declining trend towards theyear 1977 which also seems to be quite a normalpherlomena but still needs confirmation after exami-ning the data of the subsequent years to come.

Quite interesting results are found when thedata are examined for the kinds of publicationswhich have cited this article. The results areshown in the Fig. No.2 and in Tables No.5 and 6.Articles in periodicals take the first place, 517

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citing items out of 593 i. e , , 87.31. of all theitems - quite a usual and normal channel r.f carrying the scientific idea, The review articles comenext in order, taking 31 or 5.21. of all the citingitems, which is quite a large and significant Iigur e ,Another interesting observation is that the idea hastaken a very natural and nnrmal course of spread-ing. In the first instance, it was cited in a veryinformal manner in the letters, notes and dis-cussions et c , during the years 1968, 1969, and1970. During the peak of its infection, it was citedby two of the editorials in 197\. Later, during allthe ot he r years of its spreading, when it got widelyspread and subsequently stabilized, the papers havebeen cited rn ost ly by the review a r't icle s and otherf or-rn a l ized and sp e c ia l is ed media of scientificc ornmunicat ion.

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CONCLUSIONS

593 different citations appeared in 69 differentperiodicals and other publications of various coun-tries in the world, the citation patterns, spreadingtrend of the idea through informa 1 and formal media,quite ev idently establish the epidemic nature of theidea. This new idea of Plate Tectonics, having itsgenesis in 1965, originated in 1968 was definitelyof epidemic nature, created a revolution among thegeoscientists throughout the world. The idea spreadso quickly that it infected a large population allaround the world during a very short span of onlyfive years, having its maximum influence in theyears 1970 and 1971, getting stabilized through theyears 1974-76, and showing a slight decline in theyea r, 1977.

There are areas in the library and informa-tion services, where the findings of this study couldbe applied to obtain better results. Resources andservices could be organized in more efficient man-ner, specially for the scientists who are working onthe problems of plate tectonics or on related aspectsThe study has further encouraged to examine the

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nature of the publications which have c jt ed thisepidemic idea which might be quite useful to thedocumentalists, librarians and ge oac ient ist a,

I wish to thank Dr. W. C. Aiy apeku, who haa.inspired and encouraged me to take up such a study.

REFERENCES:

1. Done-hue, Joseph C. 1973. Under standingscientific literatures: A bibliographicapproach. London, M.I. T. Press; 101p.

2. Goffman, William, and Newill, Vann A.1964. Generalization of epidemic theory:An app lication to the transm is sion of ideas.Nature. 204; 225-228.

3. - --------------------.1967. Communica-tion and epidemic processes.Proceedings of the Royal Society. A 298;316-334.

4. -------------------- 1967. Mathemati-ca 1 approach to the spread of scientificideas; the history of Mast cell Research.Nature. 212; 449-452.

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