Melanie Killen, Ph.D., is Professor of Human Development and the Associate Director for the Center for Children, Relationships, and Culture at the University of Maryland. Her research is on the development of social cognition, moral reasoning, and intergroup attitudes.
Robert J. Coplan, Ph.D., is Professor of Psychology and Director of the Pickering Centre for the Study of Human Development at Carleton University in Ottawa, Canada. His research is on children's social and emotional development and peer relationships.