It’s well known that men and women differ on some personality traits, most notably neuroticism, when averages are compared. But another way to compare the sexes is by looking at how much men and women vary within their groups. In a new study, psychologists Peter Borkenau, Robert McCrae and Antonio Terracciano have done just that. Using data from 51 cultures with more than 12K participants they have looked at observer ratings of someone each participant knew well. Using a measure of the Big Five, they found that men were generally rated with more variation than women on all traits except neuroticism, which was slightly more varied for women. They also found that women rate people with more variance than men.
Why Would Men Be More Varied?
One possible explanation for this could be evolutionary. While women have a high parental investment, their reproductive success has depended on physical health and social skills. Men have had more ways to be reproductively successful – the can be hunters or gatherers, leaders, highly organized, manipulative etc. Since all of these strategies relate to personality this would mean that more variation in traits would be selected for among men than women.
A case could also be made for gender roles influencing variance – men are simply allowed a broader range of behaviors than women. This is one of those nature/nurture questions – do social norms form behavior or does behavior form the norms? One way to settle this question (in this instance) would be to look at variation in behavior that violates social norms. This can be easily found in personality disorders, conditions that constitute extreme and maladaptive personalities. These are much more common among men than women, and a big reason why the prison population is made up to 90-95 percent by men. Their behavior is extreme and unacceptable, contradicting the idea that social norms can explain the variance. So more likely, this is a product of evolution. This of course all depends on if you view personality disorders as extreme variants of normal personality or not, but both behavioral and genetic links between the two suggest that they are.
Why Do Women Give More Varied Ratings?
This may relate to the fact that women varied more on neuroticism, a trait relating to social interactions. It may be that their social skills – observation of others no doubt being a crucial part of these skills – make them more accurate judgers of personality. The authors refer to other research that has reached this conclusion. Which makes me wonder: if women are better judges of character, why aren’t they the preferred choice of raters in personality research? It’s also interesting to note how few women there are in this field given that they are superior to men in this very fundamental aspect.
Is Male Variation a Good Thing?
Given what I just said about the prison population, it’s far from certain that this male variation in personality is a good thing, neither for the individual nor for society. After all, evolution is not adaptive in the short term; there are plenty of examples of how our evolutionary nature collides with the modern environment, obesity being the most obvious. That said, crime is far from the only aspect of this variation. According to the study it concerns four of five basic factors of personality. Luckily the study included some social variables. Here is what they found,
The sex differences in variability in personality were more pronounced in the more developed, more gender-egalitarian, and more individualistic societies.
This suggests that male variation is a good thing. One explanation could be that nations compete with ideas. And variety in personality means a variety in how people in a country think, which makes for a variety of ideas that in turn translates to wealth. This variation largely coincides with IQ measure of different countries so it’s a little hard tell exactly how much of the wealth is due to intelligence and how much is due to variety.
Why Do Countries Vary in Variety?
This is probably something those Human Biodiversity buffs might have an answer to. It seems likely that inbreeding would reduce variance as well as intelligence. In line with this idea, Muslim countries (known for very high levels of inbreeding and low IQs) had on the average a lower level of male variance and those who were above average were very close to it. Some countries break this pattern by showing little male variance but high IQ levels, most notably Hong Kong and Japan. But overall, variety seems to be of great importance. This is a field of research that is still pretty new so it will be interesting to see where it leads. No doubt some traits will be more important than others, and some of these may not be captured in the Big Five model. Honesty/humility and sensation seeking come to mind. And different combinations of traits might also be important. I’ll get back to this if I find something interesting in the numbers.