Study habits and Eysenck's theory of extraversion-introversion

IOURNAL

OF RESEARCH

IN PERSONALITY

16, 139-146

(1982)

Study Habits and Eysenck’s Theory of Extraversion-Introversion JOHN B. CAMPBELL

AND CHARLES W. HAWLEY

Colgate University Predictions derived from Eysenck’s theory of personality were tested in two samples by relating extraversion scores to library study locations, frequency of study breaks, and self-report of factors which influence study location. The predicted main effects for study location were found, with extraverts occupying locations that provided greater external stimulation. Positive correlations were consistently found between extraversion and preferred level of noise. preferred level of socializing opportunities, and rated importance of socializing opportunities. The prediction that extraverts would take more frequent study breaks was supported in Sample 1 but not replicated in Sample 2. The data are interpreted as providing direct support for Eysenck’s theory of behavioral differences and mixed indirect support for his theory of neurological differences between introverts and extraverts.

Sommer (1966) provided intriguing data on students’ preferred study locations in college libraries. Students differed markedly in the architectural settings they preferred, and their self-reports indicated that the need to be with or away from other people, the amount of noise, and the presence or absence of distractions were major factors in determining study location. Although Sommer did not address the issue of personality characteristics which might covary with differential seating choice, he concluded that “the ideal library would contain a diversity of spaces that would meet the needs of introverts and extroverts” (1966, p, 246). It is certainly logical to propose that extraversion-introversion is related to differential library study locations, particularly in the context of Eysenck’s (1967) theory of personality. Eysenck discussed extraversion-introversion in terms of observed behavioral tendencies and presumed underlying neurological states. At the behavioral level, “the typical extravert is sociable . . . needs to have people to talk to, and does not like reading or studying by himself” (Eysenck & Eysenck, 1968, p. 6). Thus, the predicted relationship to study locations is explicit. A relationship between extraversion-introversion and study location can Address reprint requests to John B. Campbell, University, Hamilton, N.Y. 13346.

Department

of Psychology,

Colgate

139 0092-6566/82/020139-08$02.00/O Copyright Q 1982 by Academic Press, Inc. All rights of reproduction in any form reserved.

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also be predicted at the level of the neurological theory. Eysenck (1967) proposed that introverts have a lower threshold of arousal of the reticular activating system than do extraverts. Thus, introverts experience greater arousal to lower intensity stimulation than do extraverts. However, introverts also experience transmarginal inhibition, a reduction in cortical arousal or excitation once stimulus intensity exceeds an optimal level, at lower levels of stimulus intensity than do extraverts; thus, introverts are stimulus shy while extraverts are stimulus hungry. Indirect support for Eysenck’s neurological theory is provided by work on sedation threshold (e.g., Claridge & Herrington, 1960; Shagass & Kerenyi, 1958; but see Brody (1972) and Claridge (1967) for important qualifiers), responsivity to increasing stimulus intensity (e.g., Hill, 1975; Ludvigh & Happ, 1974; Shigehisa & Symons, 1973; Stelmack & Campbell, 1974; Stelmack & Mandeizys, 1975), and habituation (Smith & Wigglesworth, 1978). Eysenck’s neurological model suggests that introverts will prefer study locations which minimize external stimulation, while extraverts will prefer seating arrangements that provide stimulation. Morgenstern, Hodgson, and Law’s (1974) finding that introverts functioned less efticiently in a learning task in the presence of distraction, while extraverts improved their performance in the presence of distraction is consistent with this prediction. Eysenck’s conception of vigilance is also potentially of relevance to library study patterns. The basic prediction is that introverts will be superior to extraverts on laboratory tasks that entail noticing an atypical occurrence in a long and repetitive stimulus array (e.g., a moving clock hand that sporadically makes a double jump). There is considerable support for this prediction (e.g., Bakan, 1959; Claridge, 1967; Mackworth, 1961; again, see Brody (1972) regarding ambiguities in the prediction). Eysenck (1967) attributed this phenomenon to the accumulation during the task of reactive inhibition which eventually produces an involuntary rest pause (IRP). If the IRP coincides with the atypical stimuius, the subject will fail to notice and to respond to that stimulus. Since extraverts are considered more susceptible to inhibition, they should experience more IRPs and consequently exhibit poorer vigilance performance (see Eysenck (1964) regarding introvert-extravert differences in IRPs on a motor task). If Eysenck is correct, then the monotony of studying should prompt extraverts to experience more IRPs and consequently to take more “study breaks” than introverts; that is, the reactive inhibition which accumulates during studying should necessitate more frequent intermissions for extraverts. Activity during and duration of the study break may reflect the social milieu, but the origin and frequency of such study pauses should be attributable to neurological differences between introverts and extraverts. There is no direct support for this prediction in the literature; Estabrook and Sommer (1966) found

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that extraverts reported spending their study breaks with other people, but there was no reported difference between introverts and extraverts in frequency of study breaks. In summary, given Eysenck’s two-level theory, it follows that introverts should choose to study where the number of people and amount of external stimulation are minimized, while extraverts should prefer locations where socializing opportunities abound and the level of external stimulation is high. In addition, extraverts should take more frequent study breaks than introverts. Everett Needham Case Library at Colgate University provides an excellent opportunity to test these predictions. The library has three floors, representing two distinct seating plans.’ Floors 1 and 3 contain individual desk carrels and small tables interspersed among 8-ft stacks. As a consequence of the design, socializing opportunities are limited, and, the authors propose, so are noise and external stimulation in general. There are some structural differences between the two floors (e.g., windows on Floor 3 but not Floor 1); consequently, the decision on whether to equate the two floors will be based on the similarity of occupants’ ratings of their stimulation levels. Floor 2, by contrast, contains a single, large, L-shaped reading area connecting the reference and reserve desks; seating is on sofas and easy chairs or at large tables. There are no barriers to sight or sound; consequently, socializing is frequent, and the level of visual and auditory stimulation is high. Combining information about the structure of the library with the predictions derived from Eysenck’s theory, the following specific hypotheses were proposed. First, introverts will tend to study on Floors 1 and 3, while extraverts tend to study on Floor 2. Second, extraverts will take more frequent study breaks than introverts. Finally, in terms of subjects’ self-reports of what factors influence their study location, there will be positive correlations between extraversion and preferred levels of noise, crowdedness, and socializing opportunities, as well as with rated importance of socializing opportunities in choosing a study site. METHOD

Subjects Two samples of undergraduates studying at the Case library were obtained, the first in late November of 1978 and the second in late November and early December of 1979.’ The first sample contained 30 males and 27 females, while the second consisted of 29 males I The three floors actually are labeled A-level, Main, and Second. In the interest of ciarity, they will be referred to here as Floors I, 2, and 3. ’ The authors thank Christopher Gardner, Kathryn Krause, and Mary Laughlin for their assistance with the Sample I data, and Stephen Ketterer and Hilary Kopp for collecting the data in Sample 2.

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and 26 females. The number of subjects sampled from Floors 1, 2, and 3 of the library were 19; 19, and 19 for Sample I and 15, 24. and 16 for Sample 2. All subjects were between 18 and 22 years of age.

Procedure The procedures followed for the two samples were identical. The data were collected between 8:OO and 10:00 PM on week nights by an equal number of male and female interviewers. Every tenth student on a given floor, beginning with the first person the experimenter saw and continuing around the floor in a predetermined sequence, was selected to participate. Potential subjects were told they had been randomly selected to answer a survey on study skills and were asked if they would complete two brief questionnaires. The first questionnaire was Form A of the Eysenck Personality Inventory (EPI; Eysenck & Eysenck, 1968). Ten potential subjects were not included in the first sample and nine were not included in the second sample because their scores on the Lie scale of the EPI were 5 or higher. The second questionnaire focused on studying habits and preferences. Subjects were asked to indicate, on a scale from 0 to 10, the number of times per hour that they take “study breaks (e.g., talking to someone, looking around the room, walking around, etc.)” when studying in the library. On a l-to-6 scale, subjects also indicated the extent to which they were using reserve and/or reference materials that night (since these materials are located on Floor 2); how noisy their study location was at the moment; what their preferred levels of noise, crowdedness, and socializing opportunity were in the library; and how important socializing opportunities were in choosing a study location. The two questionnaires were presented in counterbalanced order. Ail subjects indicated their campus address so that a debriefing letter could be sent to them when all data had been collected for that sample.

RESULTS

The data for one subject (a male) from Sample 1 and five subjects (two males and three females) from Sample 2 were discarded prior to analysis because the subject had indicated that he/she was using reserve and/or reference materials exclusively (Le., a response of 6 on the 6-point scale) on that visit to the library. These deletions were necessitated by the fact that the reserve and reference materials are located on Floor 2 of the library. Mean extraversion scores did not differ for the two samples (Ml = 13.80, M2 = 12.88, F(1, 104) = 1.65, p = .20). Both mean scores closely approximate the mean score of 13.1 reported for American college students in the EPI Manual (Eysenck & Eysenck, 1968). There were no significant differences between the two samples on any of the criterion variables. A preliminary 3 (Floors) x 2 (Sex) analysis of variance was conducted for both samples, with perceived noise level of the studying location as the dependent variable. For both samples, neither the main effect for Sex nor the two-way interaction was significant. The main effects for Floors, however, were highly significant (F(2, 50) = 18.96, p < .OOl for Sample 1; F(2, 44) = 12.47, p < .OOl for Sample 2). As indicated in Table 1, the significance was attributable to the difference between the

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TABLE

1

MEAN NOISE LEVEL RATINGS Sample Floor 1 2 3

1

2

1.84 3.47 1.89

I .79h 3.60 2.12”

“.’ Within samples, entries with identical superscripts do not differ significantly (p < .05), using Newman-Keuls a posteriori contrasts.

mean noise levels for Floor 2 and for Floors 1 and 3. These data support the appropriateness of treating Floors 1 and 3 of the library as equivalent, since it is assumed that it is the differing levels of stimulation (e.g., noise level) on the different floors that produce their differing attractiveness for introverts and extraverts. The first hypothesis was tested by performing separate 2 (Floors 1 and 3 vs 2) x 2 (Sex) analyses of variance for each sample and for the two samples combined, with extraversion scores as the dependent variable. As indicated in Table 2, the hypothesis received consistent support; that is, individuals studying on Floor 2 of the library were, on the average, more extraverted than individuals studying on Floors 1 and 3.. The interactions of Floor and Sex were not significant: however, there was a main effect for Sex in sample two (F(1, 46) = 5.86, p < .05), such that the mean extraversion scores were 11.85 for males and 14.09 for females. The results relevant to the second and third hypotheses appear in Table 3. All correlations were positive, as predicted, and 13 of the 1.5 coefficients reached statistical significance. For two of the five criterion variables, however, there was a failure to replicate a significant correlation across samples. This problem was most flagrant, and most damaging theoretically, in the case of the Study Breaks variable. All corTABLE 2 MEAN EXTRAVERSIONSCORES Sample Floor !, 3 2 ” F(1, b F(1, c F(1,

1” 13.13

15.10 52) = 4.12, p < .05. 46) = 5.55, p < .05. 102) = 7.95, p < .Ol.

2”

Combined’

12.00 14.20

12.63 14.64

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TABLE CORRELATIONS

HAWLEY

3

OF EXTRAVERSION

WITH

CRITERIA

Sample Criterion Frequency of study breaks Preferred level of noise Preferred level of crowdedness Importance of socializing opportunities Preferred level of socializing opportunities N

1

2

Combined

.42** .23” .09 .43** ,40** 56

.04 .37** .34*+ ,41** .28” 50

.24”* .29** .20* .41** .31** 106

* p < .05, one-tailed. ** p < .Ol, one-tailed.

relations for the combined samples were statistically significant, but the lack of consistency was disconcerting. Thus, the data clearly and reliably support the predictions of relationships between extraversion and three of the four criterion variables involved in the third hypothesis (preferred noise level, importance of socializing opportunities, and preferred level of socializing opportunities), while the status of the relationship predicted in the second hypothesis between extraversion and the Study Breaks variable remains unclear. DISCUSSION

Since none of the between-sample differences in levels of extraversion or any of the criterion variables were statistically significant, the inconsistencies in obtained patterns of correlations are not directly attributable to differences in the composition of the samples. It remains possible, however, that the fact that the second sample was obtained approximately 1 week closer to the end of the semester (which occurs after the second week in December) had an effect. That is, the nearness of paper deadlines and final exams may have encouraged students in Sample 2 to take or to report fewer study breaks. This is consistent with the trend (F(1, 104) = 1.30, p = .25) for fewer study breaks in Sample 2 (Ml = 3.79, A42 = 3.18). Greater occupancy of the library might also increase the salience of levels of crowdedness for both extraverts and introverts in Sample 2, thereby strengthening the observed relationship of extraversion and crowdedness. This reasoning is ad hoc, however, and it does not mitigate the failure to find reliable relationships between extraversion and both number of study breaks and preferred levels of crowdedness. These data provide mixed support for both levels of Eysenck’s theory of extraversion. The predicted behavioral difference emerged in both samples, with extraverts occupying locations that provided greater stimItlation. This effect appeared reliably, despite the fact that both samples

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were obtained at the end of an academic term, when increased difficulty of obtaining any seat in a library that seats approximately 25% of the student population might well force some students to occupy seats they would not normally prefer. This pressure, of course, worked against the prediction by encouraging randomized seating. Although the behavioral effect is clear, the theoretical interpretation for the effect is ambiguous. Floors 1 and 3 of the library were distinguished from Floor 2 on the basis of rated noise levels or levels of stimulation. It is also possible, however, that the observed effect is attributable to increased socializing opportunities on Floor 2. This is an important issue. While the differential presence of extraverts and introverts on various floors clearly supports Eysenck’s position, an expianation in terms of levels of noise or stimulation is consistent with the neurological theory, but an interpretation in terms of differential socializing opportunities is consistent with the behavioral level of the theory. Notice that the two levels of the theory are separable. The pattern of correlations between extraversion and the five selfreport criteria is of some assistance here. Both the Study Breaks and Preferred Noise Level variables were derived from the neurological model. The predicted correlation is observed consistently for the latter variable, but inconsistently for the former. As Monte (1980) points out, however, the concept of IRPs is more clearly related to Eysenck’s (1957) early neurological model than to his current (Eysenck, 1967) model. In addition, it is possible that study breaks are sufficiently influenced by social distractions and pressures that they constitute a poor medium for testing predictions regarding JRPs.~ The two Socializing Opportunities variables, which were derived from the behavioral model, consistently demonstrated the predicted positive correlation with extraversion. The Preferred Crowdedness Level variable, which could reflect either level of stimulation or socializing opportunities, correlated positively with extraversion in Sample 2 but not in Sample 1. Thus, the pattern of correlations is somewhat more supportive of the predictions derived from the behavioral level of the theory, but the difference certainly is not compelling. In summary, the present data provide support for Eysenck’s (1967) theory regarding behavioral differences between extraverts and introverts, and they are consistent with the existing literature; however, it is not clear whether the observed differences are attributable to differential preferences for levels of stimulation or to differential preferences for levels of socializing opportunities. Although Eysenck clearly proposes that the neurological differences manifest themselves in the behavioral differences, findings consistent with one level of the overall theory do not necessarily imply support for the other level. Despite their frequent ’ Thanks

are due

to the Editor

for

suggesting

this

point.

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confounding in naturally occurring situations, further attempts to determine the relationship between and relative contribution of the two levels of Eysenck’s theory are needed. REFERENCES Bakan, P. Extraversion-introversion

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