Your Brain: The Missing Manual

Are Gender Differences Real?

It seems like an absurd question. After all, a quick look at the biological plumbing turns up a few unambiguous differences. But when dealing with people's behavior, the answer isn't nearly as straightforward.

Initially, the case for sex-specific brain differences seems to be on solid ground. Aside from the less than one percent of individuals who are born with ambiguous sex organs, people can be divided into two clear groupings—male and female—and these groupings hold in all the cultures of the world and throughout history. This is quite different than the situation with race. As you learned on The Mere Exposure Effect, the way we define races overlaps sloppily (at best) with the real genetic differences between groups of people. Tradition, migration, and the politics of power influence how races are defined—and the races themselves change, shaped by generations of romantic hookups.

However, the study of the sexes quickly runs aground when it tries to make solid links between differences in behavior and fundamental human nature—in other words, when it attempts to argue that men are genetically conditioned to act like men and women are genetically conditioned to act like women. Consider this list of average sex differences, all of which are well established in many studies:

• Men are more likely to perform outward aggressive acts (like throwing heavy objects).

• Women are more likely to show empathy (whether it's by sharing toys as a child or recognizing ...