| Abstract: | Social and political factors often have an effect on the way we perceive and think about particular events. While it is generally acknowledged that these factors are likely to change over time, the implications of such temporal changes for empirical research are not often considered. In this paper, some of these are illustrated by examining data collected from a sequence of studies conducted over a 3-year period (1973–1976). Subjects viewed the same videotaped mock (rape) trial and, prior to experimental manipulations, gave their own personal verdict. An examination of the proportion of mock jurors preferring guilty in each of the studies revealed a drift of 16% (.53 to .69) from 1973–1976. This trend toward harsher judgments was observed for both sexes, with females uniformly more likely than males to favor conviction. Ancillary evidence suggests that the upward drift reflected changes in the perception of rape during that period. The implications of temporal drift in parameter values for empirical research were illustrated by simulating jury size effects using social decision scheme theory (J. H. Davis, Psychological Review, 1973,80, 97–125). The results indicate that the magnitude of theoretical differences due to jury size must have decreased as the probability of an individual guilty vote increased over time. Thus, failures to replicate findings may not be due entirely to sampling error, methodological imprecision, or the like, but to temporal changes in the social phenomenon under investigation. |
