Michael Hogg is Professor of Social Psychology at Claremont Graduate University. He is also an Honorary Professor of Psychology at the University of Kent and the University of Queensland. His research focuses on social identity processes within and between large and small groups, and he has published widely on topics including intergroup relations, group cohesion, leadership, group motivations, and conformity processes. Professor Hogg is co-editor of the journal Group Processes and Intergroup Relations, an associate editor of the Journal of Experimental Social Psychology, and Senior Consulting Editor for the SAGE Social Psychology Program. He is a fellow of the Society for Personality and Social Psychology, the Society for the Psychological Study of Social Issues, the Western Psychological Association, and the Academy of the Social Sciences in Australia. Michael Hogg' home page: Joel Cooper received his B.A. from the City College of New York in 1965 and a Ph.D. from Duke University in 1969. He joined the psychology department faculty at Princeton University in 1969, attaining the rank of full professor in 1978. Professor Cooper's major research focus is on attitudes and attitude change, particularly as they relate to the process of cognitive dissonance. His recent work examines vicarious experiences of dissonance (i.e., feeling dissonance due to the inconsistent behavior of others) and the role of the self in dissonance arousal. Two other areas of active interest are (1) the effect of expert testimony in courts of law, and (2) gender differences in the effectiveness of information technology, particularly among school children.