Warmth (reserved vs. warm), Emotional Stability (reactive vs. emotionally stable), Dominance (deferential vs. dominant), Liveliness (serious vs. lively), Rule-Consciousness (expedient vs. rule-conscious), Social Boldness (shy vs. socially bold), Sensitivity (utilitarian vs. sensitive), Vigilance (trusting vs. vigilant), Abstractness (grounded vs. abstracted), Privateness (forthright vs. private), Apprehension (self-assured vs. apprehensive), Openness to Change (traditional vs. open to change), Self-Reliance (group-oriented vs. self-reliant), Perfectionism (tolerates disorder vs. perfectionistic), and Tension (relaxed vs. tense).The overall result:
We found a global effect size D = 2.71, corresponding to an overlap of only 10% between the male and female distributions.Which is a huge difference, dwarfing any that have been found between nations or ethnic groups. Note that is a test of personality and has nothing to do with intelligence, ability, etc.
The biggest difference is along the "utilitarian vs. sensitive" axis, which was so large that they thought it might be messing up the whole study and so reran their numbers without it; they found that most of the overall difference survived even without that one axis. (Women are more sensitive, men more utilitarian, in case you wondered.)
I'm not going to get into defending this particular test as accurate or this particular analysis as correct. But in general over the past 20 years psychology has moved more and more in this direction, finding major sex differences in all sorts of studies. This is probably because the modernist generation that gave us 1970s feminism has aged out of power and been replaced by my generation, and we are just a lot more into genetics than they were. Plus a string of legal victories for women's rights has made it less important to insist, for political reasons, that men and women are the same.
Anyway this is what the best data we have shows, and it confirms what I have found out about life; on average, men and women are different. That by itself says nothing about any particular person you happen to meet, since there are also big differences among men and among women, and the distribution of the two sexes overlaps on every axis. Nor does it say anything about why men and women are different, and much of what is being measured might be caused by socialization. Not all, since some of the differences are found in all human societies – for example that men are more violent – but anyway I think that for most purposes this just doesn't matter very much.
The challenge – and I see this as one of the biggest challenges facing humanity, bigger than economic inequality or climate change – is to create a social and political order that accommodates sex differences while maintaining a very high degree of equality. Because it is probably true that many, many people can't think in this way. Many people can't imagine that two things can be different but of the same value; the idea that "if men and women are different on average, then men must be better leaders and we should always vote for the man" seems to be widespread, entrenched at a deep psychological level. Likewise many people are bad at distinguishing between groups and individuals, thus "eight of the ten people in my 8th-grade programming camp were guys and the five best programmers I know are guys therefore no woman can program."
So I understand the impulse to claim that there are no fundamental differences between men and women, as the simplest way to create equality. But that is not what the data says. And more important, it is not what many people experience in life. Again, I don't think it matters whether these differences are biological or social in origin, because we in fact live in a world in which men and women are different, and whatever plan you come up with to reduce those differences over time is not going to change anything very quickly. There is also the practical fact that women have the babies and therefore bear much of the cost of reproduction. Right now we are faced with creating equality between two different groups of people, and that is just hard.