When men play female avatars in online games, they change the way they speak to conform to female stereotypes—but the way they move betrays their masquerade.

In a recent study reported in Information, Communication and Society, researchers created a custom-built quest in World of Warcraft—the popular online game where players can work together to slay dragons and discover magical treasures. The researchers recruited 375 World of Warcraft gamers and ran them through the quest in small groups. The quest took an average of 1.5 hours to complete, and every participant’s movement and chat were recorded and meticulously coded.

The researchers found that the men were more than three times as likely as the women to gender-switch (23 percent vs. 7 percent). When selecting female avatars, these men strongly preferred attractive avatars with traditional hairstyles—long, flowing locks as opposed to a pink mohawk. And their chat patterns shifted partway toward how the real women spoke: These men used more emotional phrases and more exclamation points than the men who did not gender-switch. In other words, these men created female avatars that were stereotypically beautiful and emotional.

Although the gender-switching men could partially talk the talk, they completely failed to walk the walk. The researchers found that all the men in their study moved around in a very different way than the women. The men moved backward more often, stayed farther away from groups, and jumped about twice as much as the women did. When it came to moving around, the men behaved similarly whether they gender-switched or not. So if you’re trying to figure out if that female Night Elf is really a man, focus on how they move around. As study author Mia Consalvo, a professor at Concordia University, says, “movement is less conscious than chat, so it can be an easier ‘tell’ for offline gender.”

It gets stranger. The lead author of the paper, Rosa Martey at Colorado State University, told me via email that “it’s not necessarily the case that men are trying to appear female when they use a female avatar. Our interviews did not suggest that those who switched were trying to ‘pretend’ to be women players.”

In fact, it’s all about the butts. Because players see their avatars from a third-person perspective from behind, men are confronted with whether they want to stare at a guy’s butt or a girl’s butt for 20 hours a week. Or as the study authors put it in more academic prose, gender-switching men “prefer the esthetics of watching a female avatar form.” This means that gender-switching men somehow end up adopting a few female speech patterns even though they had no intention of pretending to be a woman.

In my own research in virtual worlds and avatars, my colleagues and I have found that people will conform to the expectations of their avatars without consciously being aware of it. For example, we found that college students given subtly taller avatars will negotiate more aggressively in a bargaining task than students given shorter avatars. Of course, people can only conform to stereotypes that they know. Perhaps this is why we see gender-switching men conforming to stereotypes of how women talk, while not conforming to the more nuanced movement patterns.

The butt theory could also explain another consistently puzzling statistic: Why do men gender-bend so much more often than women? Given that most AAA video games and thus most of these female avatars are designed by men for a primarily male audience, gender-switching based on esthetics makes sense for male gamers. But because male avatars aren’t created by female designers for a female audience, women may not have the same incentive to gender-switch. (And no, the equivalent is not an obscenely muscular male avatar in a tank top holding a machine gun.)

Virtual worlds are often thought of as places where we are free to play and reinvent ourselves, but game design and psychology often conspire to encourage us to enact and perpetuate offline stereotypes and the status quo. The most fascinating irony of our contemporary virtual worlds may be how little they actually allow us to play.