EPA A Khasi woman sells fruits and vegetables on the Guwahati-Shillong highway in Meghalaya, India on September 28, 2013.

The sign on the road leading to the city of Shilong in the Khasi hills of northeast India had a puzzling message: “Equitable distribution of self-acquired property rights.” We asked Minott, our driver who had met us at the Guwahati airport, what it meant. A short, skinny, grinning 28-year-old, he spoke seven dialects and reasonably good English. “I do not work in the rice fields, like most men of my tribe,” he told us proudly. “I work as a translator. And a driver. And I operate a gas station in my sister’s house. And I trade goods at the market. You see! I work very hard!”

We nodded in agreement. He certainly seemed like a natural-born entrepreneur. In the U.S., Minott would undoubtedly have operated a successful franchise, or even, given the blessing of a good education, a Silicon Valley–style software startup.

But Minott’s life was constricted. “I can’t get married,” he sighed. When we asked why, he explained that, as a Khasi man, he would have to live either with his sister or with his wife’s family, and he did not want to do that. He wanted to have a house of his own, but this was impossible in his society. He was not allowed to own property. Many of the things he wanted to do required his sister’s permission, because in the matrilineal Khasi society, women hold the economic power. Even the most able, enterprising men, like Minott, are relegated to second-class citizenship. The sign on the road, Minott explained, was part of a nascent men’s movement, as the men in Khasi society began to articulate their resentment over being treated as “breeding bulls and babysitters.”

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It was clear we were in a parallel universe — and we were thrilled. In fact, we had journeyed to this matrilineal region as part of a large-scale field experiment we had designed in order to help us solve some of the most vexing economic gender questions in Western society: Do women make less money and occupy fewer management positions than their male counterparts because they are innately less competitive? Or do societal influences play a vital role in our competitive inclinations?

There was only one way to find out the answers to these questions. We had to get away from Western society. With support from the National Science Foundation, we set out to test assumptions about biologically based competitiveness in two of the most culturally different places on the planet. We conducted experiments in one society in which women held virtually no power, and in another in which they ran the show. In the process, we were able to develop scientific experiments that permitted us a unique glimpse into women’s behavior in markets across extremely different societies that held women in diametrically opposite roles. In exploring the underpinnings of their behavior, we learned that not all women from every walk of life are less competitively inclined than men.

With the help of some anthropologist friends, we identified two polar-opposite tribes — the ultra-patriarchal Masai tribe of Tanzania, and the matrilineal Khasi of northeast India. Our goal was to compare the way men and women in these tribes competed under the same experimental conditions.

We started in Tanzania on the plains below Kilimanjaro with proud Masai tribesmen, dressed in brightly colored robes and carrying their spears, follow the calling of their cattle-herding ancestors. The Masai culture is very patrilineal. The men, who tend not to wed until they are around 30 years old, marry women who are in their early teens. If you ask a man, “How many children do you have?” he will count only his sons. Women are taught from birth to be subservient. A wife is confined to working in her home and her village. If her husband is absent, a woman must ask an elder male for permission to travel, seek health care or make any important decision.

We invited Masai men and women to take part in our experiment. Participants, two at a time, were invited to step over to a private place where a member of the research team waited for them. They were told the task involved throwing a tennis ball into a bucket from a distance of about 10 ft. Each participant would get 10 tries to land the ball in the bucket. We next asked the villagers to choose one of two payment options: in the first option, participants would receive the equivalent of $1.50 — a full day’s wage — each time they landed a ball in the bucket. In the second option, they would receive the equivalent of $4.50 for each successful pitch, but only if they were better than their opponent. If both participants succeeded the same number of times, they would both get $1.50 for each success. But if their opponent proved more apt, they received no payment for the experiment. That is, we asked the participants to choose between two options: one in which their payment depended only on their success, and one in which they would compete with someone else.

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The result? Fifty percent of the Masai men chose to compete, whereas only 26% of the women did. Interestingly, this result is strikingly similar to that of the men and women we studied in the U.S. and other Western countries.

The next stop in our experiment was the matrilineal society of the Khasi — where we were greeted by Minott, the friendly driver — in northeast India. As we described, life is considerably better for Khasi women than it is for their Masai counterparts. The Khasi are one of the world’s few matrilineal societies; inheritance flows through mothers to the youngest daughter. When a woman marries, she doesn’t move into her husband’s home; rather, he moves into hers (and out of his mother’s). The mother’s house is therefore the center of the family, and the grandmother is the head of the household. Khasi women don’t do much of the farming, but as the holders of the economic power, they wield a great deal of authority over men.

We conducted ball-throwing experiments identical to those we conducted in Tanzania with the Masai men and women. In this case, the results were flipped: 54% of the Khasi women chose to compete, whereas only 39% of the Khasi men competed. Khasi women were more likely to choose to compete than even the superpatriarchal Masai men. Generally speaking, the Khasi women behaved more like the Masai (or Western) men.

Of course, we looked at the behavior of women in a society unlike most others in the world. But that was the point: to strip away, as much as possible, the cultural influences of a patriarchal society. Our study suggests that given the right culture, women are as competitively inclined as men, and even more so in many situations. Competitiveness, then, is not only set by evolutionary forces that dictate that men are naturally more so inclined than women. The average woman will compete more than the average man if the right cultural incentives are in place.

This distinction has implications for hiring managers, policymakers, business owners, educators and parents alike who want to increase diversity in the workplace, even the playing field for women in politics, increase sales to female shoppers or boost a child’s confidence on the soccer field. As unique and unusual as the Khasi are, they can help us focus more on the cultural and societal influences that hold women back instead of fixating on biological sex differences.

Adapted from the book The Why Axis: Hidden Motives and the Undiscovered Economics of Everyday Life by Uri Gneezy and John List. Excerpted by arrangement with PublicAffairs, a member of The Perseus Books Group. Copyright © 2013.