Research on groups has been a major focus of concern among psychologists and sociologists for many years. The study of groups certainly deserves a central role in these disciplines since much of our behavior occurs in groups and many important social phenomena involve groups. Issues such as leadership, conformity, group decision-making, group task performance, and coalition formation have had a long history of research. However, recently a number of other areas of research have blossomed that provide interesting new perspectives on group processes (e.g., social impact). In addition, topics of...