a conceptual perspective on group processes and intergroup relations that assumes that groups influence their members’ self-concepts and self-esteem, particularly when individuals categorize themselves as group members and identify strongly with the group. According to this theory, people tend to favor their ingroup over an outgroup because the former is part of their self-identity. With its emphasis on the importance of group membership for the self, social identity theory contrasts with individualistic analyses of behavior that discount the importance of group identifications. [proposed in 1979 by Polish-born British social psychologist Henri Tajfel (1919–1982) and British social psychologist John C. Turner (1947–2011)]