A while back on blogged on the fascinating fact that the religious gender gap is bigger in more advanced societies. In societies where men and women are “socialized” to be the same, they are actually more religiously different. (In case you’ve never been to a church, it’s women who are more religious).

Now a new piece in the Journal of Personality and Social Psychology reports that the religious gender gap is actually a special case of a much larger pattern: Personality gaps in general are bigger in more advanced societies. So are gaps height and blood pressure (!). The authors shoot down a bunch of bad explanations, and end with this speculation:

Like morphological and physiological features, sex differences in personality are vulnerable to restraining environmental pressures. As a society becomes more prosperous and more egalitarian, innate dispositional differences between men and women have more space to develop and the gap that exists between men and women in their personality traits becomes wider.

Frankly, I’m still pretty puzzled by these results. I suspect the reason, in part, is that personality tests rarely have questions that specifically get at gender identity. If these differences turn out to be smaller in less developed societies, I’ll really have to rethink my mental picture of everyday life in the pre-modern world.