Illusory correlation in the perception of group attitudes.

126 undergraduates with pro- or anti-attitudes toward nuclear power and 15 local members of a campaign for nuclear disarmament viewed opinion statements supposedly made by residents of 2 towns. One town was larger and statements from it occurred frequently, the other was small and statements from it were infrequent. Statements expressed either pro- or anti-attitudes to the building of a nuclear power station, in which one position was in a majority over the other. Despite the fact that the proportion of pro- and anti-statements was the same for both towns, it was predicted that the most statistically infrequent category, minority position/small town, would appear most distinctive and receive greatest encoding, leading Ss to overrepresent this category. It was also hypothesized that attitude-congruent positions would appear more salient than others because of their self-relevance, resulting in enhanced illusory correlation for minority-congruent attitude holders (distinctiveness plus salience). Futhermore, it was predicted that salience and therefore illusory correlation would increase as a function of attitude extremity for these Ss. All 3 predictions were supported, replicating the findings of D. L. Hamilton and R. K. Gifford (1976) that distinctiveness, operationalized as statistical infrequency, mediated an illusory correlation effect.