⁵⁷ For more on social identity theory and self-categorization theory, see H. Tajfel. (1978). “Social categorization, social identity, and social comparison.” In H. Tajfel (ed.). Differentiation Between Social Groups in the Social Psychology of Intergroup Relations. London: Academic Press. pp. 61–76; J. Turner. (1985). “Social categorization and the self-concept: A social cognitive theory of group behavior.” In E. J. Lawler (ed.). Advances in Group Processes: Theory and Research. Greenwich, CT: JAI Press. pp. 77–122. For a recent empirical study applying these theories to better understand the impact of diversity on work groups, see J. Polzer, L. Milton, and W. Swann, Jr. (2002). “Capitalizing on diversity: Interpersonal congruence in small work groups,” Administrative Science Quarterly. 47(2): pp. 296–324.