TEMPORAL PERSONALITY VARIATIONS AMONG PARTICIPANTS FROM A UNIVERSITY SUBJECT POOL

Abstract

Summary.-This study examined personality diff~rences in participants from a university subject pool as a function of the time of participation during the academic term and year. For 150 introductory psychology students with required parcicipation in a subject pool, significa~t associations were found between time of participation and specific personality variables as measured by Jackson's Personality Research Form. Significant temporal associations with more general personality modal profiles were also obtained. Investigators using university subject pools are warned that these temporal variations in personality may represent possible confounds in research. The purpose of the present study was to investigate temporal personality variations in undergraduate students in psychology who constitute a subject pool. Universiry undergraduates, including these participants, represent a significant source of psychological data. Furthermore, a recent survey of Canadian miversities (11) indicates that the use of such subject pools is increasing. Although the use of human subjects who volunteer has been the source of much investigation (1, 14, 15, 16), scant research exists on temporal confounds associated with personality variables characteristic of such subject pools. Holmes (7) has reported that university subjects with prior experimental experience have different perceptions, intentions, and performances in experiments. Holrnes and Appelbaum (8) found the conscientiousness of subjects varied as a function of the nature of those previous experiments. Adair (1) reported equivocal results, hinting that subjects volunteering at the end of an academic year might have more negative attitudes toward psychology than subjects participating earlier in the academic year. Evans and Donnerstein (6) found rhat in the term men and women were more academically oriented and more internally controlled than those participating in the term. Strube (18), finding differences in the term versus in the term in the Type A coronary-prone behavior of undergraduate subjects, suggested that differences in time of participation may introduce systematic biases into research designs. Although all of these studies have examined individual differences as a function of research experience or early versus late in the academic