MsoNormal" style="margin: 0in 0in 10pt;">Last year, Tufts University psychologist Nicholas Rule raised a few eyebrows when he published a study suggesting a man’s sexual orientation can be “accurately and rapidly perceived” simply by looking at his face. Now, a follow-up study finds female faces are equally transparent in conveying which gender turns them on.

“Sexual orientation is perceived accurately, rapidly and automatically from women’s faces,” Rule and his colleagues write in the latest issue of the Journal of Experimental Social Psychology. “Deliberation and thinking too much seems to disrupt this ability.”

Using online dating sites, Rule and his colleagues collected photos of 98 self-identified straight women and 94 self-identified lesbians, all of whom were white and in their 20s. Each image was cropped to include only the face; those with piercings or jewelry were thrown out. Twenty-one undergraduates (all but five of whom were women) viewed the photos, pressing either the L or S key to indicate they believed the face was that of a lesbian or straight woman.

“Participants’ accuracy in discriminating lesbians from straight women was significantly better than chance guessing,” the researchers found.

In a second test, the photos were cropped so tightly that only the eyes were visible. Once again, the study participants answered correctly at a rate significantly greater than chance.

In a separate study, two groups of undergraduates viewed the full-face photos. The first group was instructed to make their decisions as quickly as possible, while the second was told to give each face serious thought rather than relying on “gut instinct.”

In the snap-judgment group, the accuracy level was significantly better than chance guessing; for the deliberative group, it was not. This suggests the mechanism for determining sexual orientation is intuitive and instantaneous. Putting the conscious mind to work apparently muddies the process and decreases the chance of getting it right.

“It remains unknown what aspects of the face and its features may underlie these judgments,” the researchers write. “One hypothesis would be that lesbian women’s faces are somehow more masculine, whether by nature, nurture or both.”

In evolutionary terms, it is plausible that over the millennia, we may have developed the ability to distinguish between those who might be willing to mate with us and those who are not interested (no matter how impressive our disco dancing moves may be). Still, these results are somewhat puzzling — especially the eyes-only test. The researchers admit as much.

“Given that the targets did not significantly differ in the amount of makeup that they were wearing, that the brows were excluded from the images, and that the primary lateral contractions of the orbicularis oculi muscles (i.e. “crow’s feet”) were not visible,” they write, “it is curious what cues from the eyes might be communicating information about sexual orientation.”

Whatever the mechanism, it seems the Dusty Springfield song was right: The look of love really is in your eyes.

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