Although I've always wanted this particular superhuman power, I've never been very good at detecting other men's sexual orientation. Findings from a recent study published in the Journal of Experimental Social Psychology, however, suggest I may be underestimating my gaydar abilities.
The January 2008 study investigated people's ability to identify homosexual men from pictures of their faces alone. In an initial experiment, researchers Nicholas Rule and Nalini Ambady from Tufts University perused online dating sites and carefully selected 45 straight male faces and 45 gay male faces. All of these photos were matched for orientation (only faces shown looking forward were used) and facial alterations (none of the images contained jewelry, glasses or facial hair). To control for context, the faces were also cut and pasted onto a white background for the study. These 90 faces were then shown to 90 participants in random order, who were asked simply to judge the target's "probable sexual orientation" (gay or straight) by pressing a button. Surprisingly, all participants (both men and women) scored above chance on this gaydar task, correctly identifying the gay faces. Even more surprisingly, accuracy rate was just as good when the images were exposed at a rapid rate of only 50 milliseconds, which offered participants no opportunity to consciously process the photo.
A parsimonious explanation for these findings would be that the countenance of these photos—an online dating site—means that they're likely stereotypical in some way. In other words, perhaps it's not the target's face per se that signals his sexual orientation, but the way he expresses himself facially when trying to attract a member of the same or the opposite gender. Or maybe hairstyles are suggestive of sexual orientation. Wary of these possible criticisms, Rule and Ambady conducted a second experiment that controlled for such extraneous variables as self-presentation and hairstyle.
In this second study, the authors used images from the social networking site Facebook rather than online dating Web sites. This way, the targets hadn't so obviously selected photos of themselves meant to attract prospective sexual partners. In fact, the authors had a rather elaborate selection procedure for choosing the target photos in this follow-up study. They first searched for men who'd indicated in their Facebook profile an interest in other men. Then, they did a second search to find other Facebook users who had posted photos of these gay men in their own profile. They followed the identical criteria for straight targets. "Thus," the authors wrote, "by using photos of gay and straight individuals that they themselves did not post, we were able to remove the influence of self-presentation and much of the potential selection bias that may be present in photos from personal advertisements."
Again, the authors superimposed these male faces (this time 80 gay and 80 straight) onto a white background. They then photoshopped off the participants' hairstyles, this time truly leaving only the faces as a source of information about sexual orientation. And even with these more stringent controls, the participants were able to identify the gay faces at levels greater than chance—again even on those trials where the faces were flickered on the screen for a mere 50 milliseconds.
Furthermore, in an even more rigorously controlled series of experiments published in the Journal of Personality and Social Psychology, Rule and his colleagues replicated their discovery that people are able to accurately guess male sexual orientation. This time, the researchers demonstrated that perceivers were able to do this even when they were shown only individual features of the target's face. For example, when shown only the eye region ("without brows and cropped to the outer canthi so that not even "crow's-feet" were visible"), perceivers were amazingly still able to accurately identify a man as being gay. The same happened when shown the mouth region alone. Curiously, most of the participants underestimated their ability to identify gay faces from these features alone. That is to say, people seem to have honed and calibrated their gaydar without knowing they've done so.
Frankly, these findings are a little puzzling to me. Rule and his co-authors mention a few lackluster evolutionary reasons why it would be biologically adaptive for women to know which men aren't worth the trouble and for men to know who's not really a sexual competitor. But they also acknowledge that it's impossible to know from these findings what exactly it is about these facial features that give gays away. "Future studies," the authors wrote, "may wish to examine what aspects of these features lead to accurate judgments, what their origins might be, and how we acquire the ability to detect them."