It takes a few tries for many people to find their way to their destinations upon exiting the subway in New York City. East 57th Street is surely on the east side of Manhattan, but which way is east? With its many tall buildings and busy streets, it’s not uncommon to find yourself on the total opposite side of the city than you were supposed to be. Though this can be a problem for both men and women, women are just plain terrible at finding their way around. (Surely, your girlfriend, mom, or friend has asked for directions to the same spot more times than your boys.) It’s not a personal opinion that women are bad at navigating, it’s science. And a new study suggests man’s inherent ability to navigate comes from his early search for partners.

A man’s knack for navigation comes from his heightened ability to retain spatial information. From mentally rotating 3D objects to finding their way through new environments, and merging into high-speed traffic (is this why men are supposedly better drivers?) to using mirror images, men’s brains are simply better at collecting the information to do so. In a study from February 2013, researchers from the University of Illinois suspected that these skills were adaptive; those who were better at moving around wound up with more offspring. However, they ended up concluding that it was due to testosterone, and said that if spatial skills was adaptive, women should have learned it too. In eight out of 11 species analyzed, including cuttlefish, deer mice, horses, and rhesus macaques, males had better spatial skills —even women who were given testosterone showed improvement.

The current study shows that the University of Illinois researchers may have been on to something. To find out, researchers from the University of Utah looked at the traveling and mating patterns of the Twe and Tjimba tribes living in northwestern Namibia, in a mountainous, semi-arid desert region. The team chose these tribes because the resemblance their style of living has to that of our ancestors, characterized by foraging for food, tending gardens, and a “comparatively open sexual culture,” first author of the study Layne Vashro said in a statement. “They have a lot of affairs with people they’re not married to, and this is accepted in the culture.”

Put this tendency toward promiscuity together with the tribes’ yearly migrations of over 120 miles, and you have the perfect mix for widespread fatherhood — and a good argument for why men’s spatial skills could have developed to embrace mating. “Navigation ability facilitates traveling longer distances and exploring new environments,” Vashro said. “And the farther you travel, the more likely you are to encounter new mating opportunities.”

Vashro and her team performed multiple tests spatial skills tests on the tribes’ men and women, and also asked them about the places they visited, and how far they traveled to get there. Of the spatial skills tasks they were asked to complete, one included showing tribespeople a series of hands on a computer screen, presented palm up and down, and pointing in different directions. After allowing them to look at the hands for a bit, the researchers gave each tribesperson up to 7.5 seconds to determine whether each image was a left or right hand. In another test, measuring navigational skill, the tribespeople were asked to point to nine different places within 80 miles of where they stood, while the researchers measured their accuracy with a GPS compass.

In all of the tasks, men performed better than women, including in the two mentioned above. On average, the men visited 3.4 locations while traveling 30 miles for each one, whereas women only visited an average of two while traveling 20 miles for each one. The researchers also found that men who did better on the hands task were also the ones who traveled the furthest in their lifetimes.

“Why men should be better at mentally rotating objects is a weird thing,” said senior author Elizabeth Cashdan, an anthropology professor at the university, in the release. “Some people think it is culturally constructed, but that doesn’t explain why the pattern is shared so broadly across human societies and even in some other species.” Thus, she concluded that men, more than women, benefited “reproductively from getting more mates, and ranging farther is one way they do this.”

Source: Vashro L, Cashdan E. Spatial cognition, mobility, and reproductive success in northwestern Namibia. Evolution & Human Behavior. 2014.