Most adults can probably recognize when another person is experiencing a sexual orgasm just by the expression on that person's face — whether it's a man or a woman, and regardless of ethnicity. But according to a new research study carried out by psychologists at the University of Glasgow in Scotland and other European institutions, and published in the prestigious Proceedings of the National Academy of Sciences, the conventional wisdom about what an "O-face" looks like may not be correct after all.
According to the findings of the team led by University of Glasgow psychologist Rachael E. Jack, people who grew up in Western cultures have a very different idea of what the human face during orgasm looks like, than people from Asian cultures, according to a Newsweek account of the study, which was published online in PNAS on October 8.
The study also examined a finding of several previous studies — that pain and orgasm look the same on the human face, and that it's impossible to tell the difference between a person who is hurting and one who is in the throes of peak sexual pleasure. But that previous finding is also incorrect, according to the research paper, titled "Distinct Facial Expressions Represent Pain and Pleasure Across Cultures."
Watch a video summary of the study's findings, below.According to a summary published by the site Inverse, the study used advanced machine learning technology to create 3,600 animated facial expressions. A group of 40 "observers" — equally divided between people from Western and East Asian cultures — were then asked to rate each expression on a scale of "very strong" to "very weak," based on whether they thought the expression was one of pain or orgasm. Expressions that fit neither description were discounted under the label "other."
The study found that to Western observers, an orgasmic face included a wide-open mouth and open eyes. But to the Asian observer, an orgasm was indicated by a closed, smiling mouth and closed eyes. The common element between Eastern and Western orgasm faces, however, was that both are marked by outward, expansive movements of the facial muscles.
Pained expressions, on the other hand, are characterized by clenched, inward motions of the facial muscles, "including brow lowering, cheek raising, nose wrinkling, and mouth stretching," the researchers wrote. But unlike orgasmic expressions, which differ based on the cultural background of the observer, facial expressions during physical pain are universal — basically the same across the cultures studied by the psychologists.