Psychology for much of the 20th century was dominated by the view that men and women were psychologically identical. So pervasive was this assumption that research articles in psychology journals prior to the 1970's rarely bothered to report the sex of their study participants. Women and men were understood to be interchangeable. Findings for one sex were presumed to be applicable to the other. Once the American Psychological Association required sex of participants to be reported in published experiments, controversy erupted over whether men and women were psychologically different. The past three decades of empirical research has resolved this issue, at least in delimited domains. Although women and men show great psychological similarity, they also differ in profound ways. They diverge in the sexual desires they express and mating strategies they pursue. They differ in the time they allocate to friends and relentlessness with which they pursue status. They display distinct abilities in reading other's minds, feeling other's feelings, and responding emotionally to specific traumas in their lives. Men opt for a wider range of risky activities, are more prone to violence against others, make sharper in-group versus out-group distinctions, and commit the vast majority of homicides worldwide. The question 'Do men and women differ psychologically?' has been replaced with more interesting questions. In what ways do these sex differences create conflict between men and women? Have the selection pressures that created these differences vanished in the modern world? How can societies premised on equality grapple with the profound psychological divergences of the sexes?
DAVID M. BUSS is Professor of Psychology at the University of Texas, Austin, and author of several books, most recently The Dangerous Passion: Why Jealousy is as Necessary as Love and Evolutionary Psychology: The New Science of the Mind , and The Evolution of Desire: Strategies of Human Mating.