It is an honor to contribute to the series of volumes based on the MacEachran Memorial Lectures sponsored by the Department of Psychology at the University of Alberta. I delivered my lectures in October, 1985, and in the ensuing months prepared a book manuscript based on the lectures. The opportunity to present a preliminary version of the manuscript to an interested audience at the University of Alberta is very much appreciated. Professors Brendan Rule and Eugene Lechelt were responsible for the many arrangements that were made for my visit. I am grateful for their efforts as well as for the hospitality of the other faculty and the graduate students at the University of Alberta.
For some time I had thought about writing a book presenting a socialrole theory of sex differences and incorporating some of the new metaanalytic work in this research area. I had not undertaken such a project because I was always in the midst of one project or another that seemed essential to developing my understanding of sex differences. Because the invitation from the University of Alberta fortunately came at a time when several of these projects were nearing completion, I was able to respond to the invitation by preparing the overview that this book contains.
Part of this book presents my own research, which I carried out in collaboration with several persons when they were graduate students. Wendy Wood and Linda Carli were my main collaborators on this research when I was on the faculty of the University of Massachusetts, and Valerie Steffen was my main collaborator during the more recent years when I have been on the faculty of Purdue University. Maureen Crowley, Patricia Renner, Carole Chrvala, and Mary Kite also made important contributions to this research while I have been at Purdue. The efforts of these individ