In the United States, the debate over multiculturalism is usually cast almost exclusively in terms of racial/ethnic differentiation. Although ethnic identity is both psychologically and socially highly significant, it is rarely the case that ethnicity is the only significant group membership that an individual has. As members of a large and complex society, Americans are differentiated or subdivided along many meaningful social dimensions, including gender and sexual orientation, life stage (e.g., student, worker, retiree), economic sector (e.g., technology, service, academics, professional), religion, political ideology, and recreational preferences. Each of these divisions provides a basis for shared identity and group membership that may become an important source of social identification. Further, most of these differentiations are cross-cutting in the sense that individuals may share a common ingroup membership on one dimension but belong to different categories on another dimension. Hence, having multiple group memberships reduces the likelihood that one's social world can be reduced to a single ingroup-outgroup distinction. The purpose of this proposed program of research is to determine how an individual's awareness of his or her own multiple group memberships and social identities contributes to tolerance and acceptance of diversity in the society as a whole. Drawing on a theory of social identity complexity (Roccas & Brewer, 2002), a program of five sets of studies employing both correlational and experimental methods will assess the antecedents of social identity complexity and test the hypothesis that increasing social identity complexity will enhance identification with inclusive, superordinate social categories and consequent acceptance of difference and diversity within the superordinate group.
