As in previous studies, people were better than chance at guessing whether the faces belonged to gay or straight people. In a first for studies of this kind, the researchers were able to directly compare how people did when judging the sexual orientation of men versus women. They found that people were better at judging women correctly. There were fewer “false alarms” than when looking at men, Tabak said, meaning instances when a straight person was judged gay.

“Why this is we can only speculate,” he said. “It’s really interesting to speculate that there might be this ironic effect that because we’re more familiar with the concept of gay men [in the media], maybe we’re more liberal with labeling a man gay.”

When looking at upside-down faces, people were still able to guess their sexual orientation correctly at rates better than chance — although not quite as accurately as when the faces were right-side up. That suggests both facial features (which can be processed in upside-down and right-side-up photos) and facial configuration provide hints into orientation, the researchers report Wednesday (May 16) in the journal PLoS ONE.