Another novel finding: in both experiments, participants were more accurate at judging women’s sexual orientation (64 percent) than at judging men’s (57 percent). Lower gaydar accuracy for men’s faces was explained by a difference in “false alarms”: participants were more likely to incorrectly categorize a straight man as gay than to incorrectly categorize a straight woman as gay.

Why might “false alarm” errors be more common when judging men’s sexual orientation? We speculate that people overzealously interpret whatever facial factors lead us to classify men as gay. That is, it may be that straight men’s faces that are perceived as even slightly effeminate are incorrectly classified as gay, whereas straight women’s faces that are perceived as slightly masculine may still be seen as straight. That would be consistent with how our society applies gender norms to men: very strictly. (Decades of research has established that, at least in our culture, it is considered much more problematic for a boy to play with Barbie dolls than for a girl to play rough-and-tumble sports.)

We know that gaydar research may elicit discomfort. To some, the idea that it’s possible to perceive others’ sexual orientation from observation alone seems to imply prejudice, as if having gaydar makes you homophobic. We disagree: adults with normal perceptual abilities can differentiate the faces of men and women, and of black and white people, but such abilities do not make us sexist or racist.

Though gaydar may not be driven by homophobia, it is relevant to discrimination policy. One of the arguments against nondiscrimination protection for lesbian, gay and bisexual people is that if sexual minorities concealed their identities — à la “Don’t Ask, Don’t Tell” — discrimination would not be possible. We believe that such policies are unfair. But fairness aside, scientific experiments like ours indicate that such policies are also ineffective: discrimination against sexual minorities would not be eliminated by nondisclosure of sexual orientation, since sexual identity can be detected through appearance alone.

Should you trust your gaydar in everyday life? Probably not. In our experiments, average gaydar judgment accuracy was only in the 60 percent range. This demonstrates gaydar ability — which is far from judgment proficiency.

But is gaydar real? Absolutely.