I read a fantastic piece a few years ago which discussed behavioural differences between men and women. They argued that there are two essential behavioural differences between the sexes:

1. Women tend to have more intimate social networks than men. (Fewer people, stronger connections).

2. In almost every aspect of life, women tend to deviate less from the mean. For better and often for worse, men are bigger risk takers.

This second point I find really interesting. Lots of statistical gender differences can be explained by this one fact. Apparently, if you plot male and female behavioural patterns on just about any scale (income, crime, exam marks, etc), women cluster around the mean more than men.

Some of the effects of this:

- There are more men in prison.

- More men run big companies.

- Statistically, girls do better at high school. This is because the dropout guys bring the mean mark down more than the high achievers bring it up.

The best evolutionary justification I've heard is that humans were polygamous for large periods of our evolution. In a society where the top blokes got all the babes, it made a lot of sense to be a big risk taker. -- How else do you compete with attention from war heroes?

There was no benefit to risktaking behaviour in women because most women would reproduce anyway.