Assistant editor and Opinions contributor

Protesters raise their hands with peace signs in Huntington Beach, Calif. (Eugene Garcia/European Pressphoto Agency)

It’s a popular trope: Women are from Venus, men are from Mars. Women are more nurturing, disapprove of violence and strive more for peaceful diplomacy. Men are more aggressive and more likely to approve of violence or war.

But is any of that really true? Probably not.

A study recently published by the National Bureau of Economic Research shines some fascinating historical light on this question. The paper looked at female rulers of European countries from 1480 to 1913 (including 193 reigns in 18 different polities) and whether their countries ever engaged in military conflict. As it turns out, women have a pretty bad record as peace-keepers: Queens were 27 percent more likely than kings to participate in inter-state conflicts.

Part of that disparity comes from the fact that political rivals often viewed female rulers — especially unmarried queens — as vulnerable to attack. But in fact, married queens were actually more likely to be aggressors than their male counterparts.

It’s unwise to make broad claims about female rulers based on limited data (after all, the study only analyzed a total of 29 queens). But it does offer some empirical evidence for a question that’s difficult to answer: Would having more women in leadership positions lead to less violence?

Women have always been a small fraction of leadership positions in the modern world, and as a result, it’s hard to tell whether they are any less bellicose than male leaders. Margaret Thatcher famously went to war with Argentina to defend her nation’s claims to the Falkland Islands. And the United States has its own share of female foreign policy “hawks” — from Sen. Dianne Feinstein (D-Calif.) to Carly Fiorina to Sarah Palin. Even Hillary Clinton presented herself as one of the more hawkish candidates during the 2016 campaign season: Unlike most of her male opponents, she expressed willingness to take military action against the Bashar al-Assad regime in Syria.

Yet polls consistently find that most women are less likely to support military action than men in almost every context. They have been less likely to support the wars in Iraq and Afghanistan than male voters. They are also less likely to support drone strikes. But political scientists argue this can partly be explained by a diverging partisan gap between men and women (women are considerably more likely to identify as a Democrat than men). Others say it’s a result of “socialization,” as men are more likely to be involved in situations involving physical force, such as jobs in military combat.

In fact, scientific research bears out the question of difference in aggression between the sexes pretty well. Psychologists have conducted dozens of studies and meta-analyses on the psychological differences between women and men, and the majority of the evidence suggests that sex has either no or a small effect.

So why does the idea that men are naturally more aggressive than women persist so strongly? There are likely bigger misconceptions at play. Men undeniably commit the vast majority of violent crime in the United States, but this may be more a cultural or societal phenomenon than inherent to men. For example, we often hear about the crisis of domestic violence against women, but more than 200 studies show that women are just as likely to initiate domestic violence as men. The disparity in victims, it seems, comes as a result of men overpowering women in physical confrontations as well as men failing to report incidents as frequently as women.

Overall, the evidence so far suggests strongly that men and women just aren’t that different in terms of being aggressive or willing to employ violence. What matters more is the context of their behavior — or in terms of war, their political ideology.

So maybe it shouldn’t be too surprising that female rulers throughout history haven’t been more peaceful than men. Maybe they’re not from different planets after all.

Read more:

We’ve been misled on the difference between genders

Mammograms deserve more skepticism

Why women in science are lonely — and shouldn’t be