The study also squared its personality findings against “gender equality,” as measured by the Global Gender Gap Index, a report that tracks progress toward greater equality in more than 100 countries by evaluating factors like economic opportunity, educational attainment, health, and positions at high levels of government for men and women.

The results showed that greater gender equality is associated with stronger expressions of gender difference. Gender differences, “should not be interpreted as results of unequal treatment, but as indicator of successful gender-equality policies,” writes the study’s author, Tim Kaiser.

“It is important to note that the differences not only increase for ‘stereotypical female’ personality facets such as emotionality or compassion,” Kaiser told me. “In more egalitarian countries, women also score higher than men on facets such as assertiveness or achievement-striving.”

On the other side of things, says Kaiser, men experience more self-consciousness than women in countries with greater gender equality, “so it could very well be the case that personality adapts to changing societal conditions.”

Previous studies have found similar results of existing differences between men and women. A 1994 meta-analysis that looked at international data from between 1940 and 1992, consisting of more than 100,000 subjects, found that women scored higher for anxiety and extroversion. Another study looked at more than 10,000 Americans and found personality differences between genders, but these differences were more stereotypical than Kaiser’s findings: Women scored higher in sensitivity and warmth, while men scored higher in dominance and vigilance.

Still, research into these differences can be hotly contested, and the multitude of variables at play makes the reasons behind the results—which aren’t necessarily tied to gender—difficult to pin down. For instance, the dataset was based on an online questionnaire that study participants “discovered ... on their own or by word-of-mouth,” according to the paper accompanying the dataset. And this questionnaire was only offered in English. The study notes that because of these factors, people who don’t have internet access, don’t speak English, or are from less-developed countries were less likely to participate in the survey. That lack of diversity could potentially skew results.

Andrew Gelman, a statistics professor at Columbia University who was not involved in the study, has some questions about the data included—and not—in the study. “I’m concerned that the responses to the survey questions will have different meanings in different countries,” he says. For example, study participants asked to evaluate their “assertiveness” might interpret their own assertiveness differently if they live in Iran or Finland. “I could well imagine that these responses would have different interpretations in Latvia, Iceland, and Finland than in Iran, Mexico, and Jamaica,” he says. “I’m concerned that these issues will be correlated with key variables in the study.”