Introduction

The way men and women behave is the end-result of a long historical process and a much longer evolutionary one. Many of the sex differences we observe today, such as those in mating and reproductive behaviour, and in aggression, are similar to those found in other animals, and fit the pattern expected from evolutionary principles. Some differences between men and women are less obviously connected to their different reproductive roles, but none the less have attracted evolutionary explanations. Findings indicating the superiority of women in certain memory tasks involving widespread scattered objects have been attributed to women's specialisation for gathering widely scattered plant foods in the human ancestral environment. This explanation is specific to the human species, as the division of labour into male hunters and female gatherers of plant food is found only in humans.

Other sex differences may be associated with the historically more recent division of labour into work outside the home and in the domestic sphere. This is one of the major implications of the social role theory introduced in the previous chapter (Eagly, 1987; Eagly et al., 2000). Men and women typically show a range of differences in their social behaviour that correspond to instrumental and expressive traits. For example, women show greater emotional sensitivity and responsiveness than men (Grossman and Wood, 1993), and men are more likely than women to take charge in groups that are engaged in a specific task (Eagly and Karau, 1991).