However, if you read the actual methodology used in the study, you'll see that the entire population studied was from only one country, the US:
"Personality measures were obtained from a large US sample (N = 10,261)"
This is culturally arrogant at best, but it's now intellectually indefensible. It has recently been demonstrated that one of the most profound gender differences in the brain (math ability) is purely a cultural artifact, when you look at international populations:
Therefore, what the original study says -- that there are enormous personality differences between the genders -- is deceptive. All it means is that, in the U.S., huge gender-based personality differences are tolerated, or even encouraged and trained.
As an international traveler all my life, I could have told you that for free!
In the math study, one researcher said, "People have looked at international data sets for many years. What has changed is that many more non-Western countries are now participating in these studies, enabling much better cross-cultural analysis."
In short, there is no excuse for such sloppy social science as the "gender-based personality differences" researchers have perpetrated.
Believe it or not, the U.S. is not a good template for studying the entire human population. It's only a good template for studying the U.S.
Since these scientists are working from Italy and Britain -- both countries with famously self-satisfied national identities -- you'd think that would be more apparent to them.
It's disturbing to see such cultural subjugation in science. One expects a degree of cultural infatuation in other realms (like cinema and music, which depend on cultural blending for their development), but not in science. Science requires a bit more intellectual integrity, if not clearer thinking.