ABSTRACT
This chapter describes a set of experiments that have undertaken to test the motivational properties of both assimilation and differentiation needs. The first experiment assessed the effect of motive arousal on rated importance of group memberships to a person's sense of self. The second experiment was designed to assess the effects of differentiation needs and assimilation needs respectively on motivated activation of different aspects of the self-concept. When the differentiation motive has been aroused, importance should be more sensitive to group distinctiveness than when the assimilation motive has been aroused. Membership in common social groups was more important for participants in the motivation arousal conditions compared to control subjects. When a particular social identity is optimally distinctive or when assimilation motives have been aroused, self-stereotyping should be particularly strong. People apparently do not simply passively process salient category distinctions but actively invoke selected social identifications in response to current motivational states and threats to optimal identity.
