Robert Lee Burgess (Ph.D., Washington University in St. Louis, 1969) is Professor of Human Development at the Pennsylvania State University. He has degrees in anthropology, psychology, and sociology. He has published numerous articles in journals and chapters in books dealing with such topics as theory construction, the development of criminal behavior and illicit drug use, cooperation and competition in children's groups, the development and consequences of power differences in dyads involved in exchange relationships, and the role of imitation in retarded children. He is al...