Our understanding of the similarities and differences between the two genders has varied with cultural shifts. For much of recorded history, women were seen to be vastly different from men and even inferior—weak, passive, irrationally emotional, and intellectually impaired. The feminist movement in the 1970s reacted against these derogatory views, shepherding in an emphasis on the similarities between the genders.

In recent decades, however, there has been increased attention paid to the ways that men and women differ. Although we cannot know for sure how much of these differences derive from biology or from environment (nature vs. nurture), research does suggest that men and women are not the same. In 1990, Janet Shibley Hyde published a meta-analysis of studies on gender differences across several psychological traits. She found that men scored considerably higher than women on tests of aggression and mathematical ability, and moderately higher on tests of certain spatial abilities. Women did better than men, however, on tests of verbal ability.

Another way that men and women may differ is in their response to stress. The “tend and befriend” model was proposed by Shelley Taylor and colleagues in 2000. They suggest that, compared to men, women are more likely to exhibit nurturing and affiliative behavior in response to stress. This appears to be mediated by the interaction between estrogen and oxytocin. Men, on the other hand, are more likely to exhibit a “fight or flight” response to stress, mediated by the brain chemicals norepinephrine and epinephrine. The male sex hormone testosterone may also support men’s “fight or flight” responses.

It is important to keep in mind, however, that we cannot know how much of these differences are learned and how much are hard-wired. While it is reasonable to believe that men and women differ, the degree of those differences might be strongly influenced by cultural and environmental factors. Even biological processes can be strongly influenced by environment.