Assimilation and differentiation needs as motivational determinants of perceived in-group and out-group homogeneity

The goal of the present research was to demonstrate the influence of perceiver motivations on perceptions of in-group and out-group homogeneity. Based on Optimal Distinctiveness Theory (Brewer, 1991), it was predicted that arousal of assimilation and differentiation needs (through threats to intragroup standing and intergroup distinctiveness) would lead to heightened perceptions of both in-group and out-group homogeneity. Because perceived homogeneity enhances both intragroup assimilation and intergroup contrast, such perceptions can serve both the need for increased inclusion within the in-group and the need for increased distinctiveness between in-group and out-group. As predicted, compared to no-arousal controls, participants in the assimilation and differentiation arousal conditions showed heightened perceptions of in-group and out-group homogeneity, greater. perceived in-group stereotypicality, and the tendency to be more restrictive in defining in-group membership, (C) 2001 Academic Press.