CONTRIBUTORS Numbers in parentheses indicate the pages on which authors’ contributions begin. Peter J. Carnevale (235), Department of Psychology, New York University, New York, NY 10003 Carsten K. W. de Dreu (235), Department of Psychology, University of Amsterdam, 1018 WB Amsterdam, THE NETHERLANDS Daniel T. Gilbert (345), Department of Psychology, Harvard University, Cambridge, MA 02138 E. Tory Higgins (293), Department of Psychology, Columbia University, New York, NY 10027 Michael A. Hogg (1), Centre for Research on Group Process, University of Queensland, Brisbane, OLD 4072, AUSTRALIA Olivier Klein (135), Service de Psychologie Sociale, Universite´ Libre de Bruxelles, 1050 Bruxelles, BELGIUM Daan van Knippenberg (1), School of Management, Erasmus University, Rotterdam, 3000 DR, Rotterdam, THE NETHERLANDS Arie W. Kruglanski (293), Department of Psychology, University of Maryland, College Park, MD 20742 Mario Mikulincer (53), Department of Psychology, Bar-Ilan University, Ramat Gan 52900, ISRAEL Antonio Pierro (293), Department of Development and Socialization, Univerita` di Roma ‘‘La Sapienza,’’ Rome, ITALY Phillip R. Shaver (53), Department of Psychology, University of California, Davis, CA 95616 Mark Snyder (135), Department of Psychology, University of Minnesota, Minneapolis, MN 55455 Timothy D. Wilson (345), Department of Psychology, University of Virginia, Charlottesville, VA 22904 ix SOCIAL IDENTITY AND LEADERSHIP PROCESSES IN GROUPS Daan van Knippenberg Gandhi, Mandela, Roosevelt—all great leaders, but without followers would they have been able to lead? Leadership is a relational term—it identifies a relationship in which some people are able to influence others to embrace, as their own, new values, attitudes, and goals, and to exert effort on behalf of and in pursuit of those values, attitudes, and goals. The relationship is almost always configured by and played out within the parameters of a group—a small group like a team, a medium sized group like an organization, or a large group like a nation. Arguably, good leadership inspires others to adopt values, attitudes, and goals, and to behave in ways that serve the group as a collective, and that define membership of the group (e.g., Bass, 1985; Burns, 1978). Thus, effective leaders are able to transform individual action into group action. Leadership is a core feature of social groups—it is very difficult to think about groups without thinking about who leads or manages them, and about how well they are led and managed. This characterization of leadership, which is not uncommon (e.g., Cartwright & Zander, 1968; Chemers, 2001; Conger & Kanungo, 1998), places a premium on the role of group membership and group life in the analysis of leadership. Leadership is quite clearly a social psychological phenomenon that is inextricably grounded in social relations, group life, and the psychology of group membership. Not surprisingly, the study of leadership has long been a central concern of social scientists—the literature is enormous, stretching back to Plato and beyond—and in particular of social psychologists. What is surprising, then, is that in the past 25 years there has been relatively little leadership research conducted within social psychology. Only in the past few 1 ADVANCES IN EXPERIMENTAL SOCIAL PSYCHOLOGY, VOL. 35 Copyright 2003 Elsevier Science (USA). All rights reserved. 0065-2601/03 $35.00 2 HOGG AND VAN KNIPPENBERG years has this changed—there has been a strong