“You’ve lost the warrior instinct,” explained my friend’s boss as he fired her after years of 100-hour work weeks. Delivered to a female employee, the comment contained an undercurrent of sexism and, when combined with some of her on-the-job experiences, probably constituted what civil rights lawyers call an “actionable statement.” My friend, however, chalked it up to the macho, hyper-competitive environment of her chosen profession: investment banking.

It’s a classic stereotype, and not just on Wall Street: Men aggressively compete; women collaborate and nurture. It’s also a view that’s been well-studied in recent years by experimental economists, researchers who, rather than simply observing economic activity out in the world, put subjects in labs and ask them to play economic “games” in a controlled environment. These economists have found that American men don’t disappoint, choosing to play more competitive games than female subjects (and sometimes performing better than women in competitive situations). Yet researchers have found that the stereotype isn’t universal—in at least one society, women have stronger competitive drives than men. It appears that the warriors are made, not born.

Why might we expect men to be more competitive? Like many gender differences, the “competitiveness gap” is taken as simply human nature. That is, at some point in our species’ distant past, competitive instincts were more important for males’ ability to survive and reproduce than for women’s. Yet in Western societies, we’ve also been raised to conform to a set of social norms and to frown upon those who defy them. From a young age, girls are dressed in pink, read princess stories, and instructed that aggression and assertiveness are unbecoming. Boys may remember “don’t play like a girl” as a standard schoolyard exhortation—from classmates and coaches alike—to play more aggressively.

Whether it derives from nature or nurture, experimental economists Muriel Niederle and Lise Vesterlund have confirmed the stereotype is true: Men are more competitive than women. The researchers set students at the University of Pittsburgh to work adding columns of two-digit numbers, paying them for their correct responses. In the first round, subjects were paid based on the number of arithmetic problems they could solve in five minutes, regardless of how others performed. In the next round, subjects were put in a tournament where only the fastest problem-solver got paid anything. After these two rounds, Niederle and Vesterlund gave their subjects feedback on how they had performed, and how they’d done relative to other subjects. Armed with information on their abilities relative to others in the group, subjects then chose whether, for the final round, they’d prefer to get paid for each problem solved or to compete in a tournament.

Men and women proved to be equally proficient in adding their columns of numbers, both when paid per problem and under the competitive pressures of a tournament. men (and boys) respond better to competition than women, both in lab experiments and also when thousands of dollars are on the line in professional tennis tournaments“> Despite their similar abilities, when given the choice of whether to compete, men were twice as likely as women to opt for the tournament in the final round. The researchers attribute about half of this difference to factors like male overconfidence in their adding abilities; the rest suggests some underlying male penchant for competition.

Of course, the behavior of Pitt students doesn’t necessarily generalize to all of humanity. So experimental economists Uri Gneezy and John List teamed up with Ken Leonard, a development economist, to test whether the “male warrior” stereotype is actually a universal phenomenon. The researchers repeated a version of Niederle and Vesterlund’s experiment with participants drawn from the Maasai of Tanzania and the Khasi of northeast India. (Subjects were paid for the number of balls they tossed into a basket, rather than doing arithmetic.)



The Maasai are a patriarchal society of cattle herders. The researchers note that among the Maasai, wives are seen as less valuable than a man’s cattle. By contrast, the Khasi are a matrilineal culture, in which family life centers around the mother’s house and both inheritance and clan membership are passed on through daughters. Among the Maasai, the researchers found a male preference for competition that was comparable to that of University of Pittsburgh undergrads. By contrast, in the Khasi group, the pattern reversed itself—it was women who preferred competition.

Why Khasi women are relatively competitive is a matter of speculation. The authors suggest that it may stem from the relatively uncommon practice of female-directed household decision-making and inheritance. In the Khasi society, women who learn to compete for resources get to keep the fruits of their efforts, and also pass on the wealth they generate to their daughters. Regardless of the underlying cause, the work of Gneezy, Leonard, and List proves that the Western stereotype of the male competitor isn’t universal: The male “warrior instinct” is a matter of socialization rather than instinct. (More recent work by Jane Zhang, an economics doctoral student at the University of California-Berkeley, further bolsters this view—in a set of experiments she ran in China last summer, Zhang found that neither gender had a stronger preference for competition in the communities she studied.)

If competitive instincts aren’t hardwired into the male mind, there may be hope for us to find a balance between the Khasi and Maasai ways of socializing the next generation (though social norms are very slow to change). At a minimum, we can work harder to equip young women with the knowledge and skills to compete in what remains a man’s world. But perhaps the problem isn’t one of female passivity—many have claimed that if women ran the world, there wouldn’t be any wars, and anyone who has read testosterone-driven Wall Street accounts like Liar’s Poker, or more recently House of Cards, might question whether all-out competition is the best way of managing our economy. If competition is nurture rather than nature, perhaps we’d all be better off if we lost a little of our warrior instincts.