He received his undergraduate degree from Harvard University and his PhD from Yale University. He was an assistant and associate professor at Stanford University and a full Professor at Columbia University. His research has focused on social influence, the effects of crowding and jury decision making. He has worked with a number of crown and defense attorneys as an expert witness on various matters related to his research. He came to the University of Toronto as Chair of the Department of Psychology. During his time here he has served as director of graduate studies in the Psychology Department for many years and was also interim chair of the department for one year. In the past two years he was the Acting Vice-Dean, Research and Graduate, of the Faculty of Arts and Science and then the Acting Vice-Principal (Academic) and Dean of the University of Toronto Scarborough.