Men’s facial morphology appears to act as a valid cue of sociosexuality, according to new research published in Evolution and Human Behavior. The study found evidence that women could predict a man’s attitude towards casual sexual relationships based purely on the shape of his face.
“We were initially interested in it from a purely academic point of view,” said study author Ian D. Stephen, an associate professor of psychology at Macquarie University in Australia.
“Evolutionary psychologists theorize that attraction is a mechanism for identifying healthy, fertile, appropriate mates. If this is correct, then two things must be true: there must be cues in our faces and bodies that reflect aspects of physiology and psychology; and there must be mechanisms in our brains that can extract this information from the cues and use it to form impressions.”
“Being able to tell whether someone is likely to be interested in serious relationships or just one night stands would be very useful for both men and women when selecting partners. So we decided to see whether that information was reflected in the face, and whether observers can extract that information to form accurate impressions.”
In the study, 103 Caucasian individuals were photographed and asked to complete an assessment of sociosexuality, meaning their openness to casual, uncommitted sexual relationships. Using a technique known as geometric morphometric methodology, the researchers were able to find a relationship between sociosexuality and facial shape characteristics among men but not women. Heightened sociosexuality in men was associated with longer faces, higher foreheads, longer noses, and larger eyes.
In a second study, which included 65 participants, the photographs were then shown to members of the opposite sex, who were asked to assess the sociosexuality of the person shown in each photograph. The researchers found that women’s perception of sociosexuality was associated with men’s self-reported sociosexuality scores, indicating that women could predict men’s sexual behavior and attitudes. But men’s perception of sociosexuality was not associated with women’s self-reported sociosexuality scores.
“It turned out that women were really good at judging whether men were only interested in short-term uncommitted relationships,” said co-author Joe Antar in a news release. “This is a really valuable skill to have, as it would allow women to make subconscious decisions about which men would be a good fit for them, according to their relationship goals.”
Using their data, the researchers also created pairs of facial composites that represented high- and low-sociosexuality faces. The researchers found that participants were able to correctly identify the high sociosexuality composite better than chance — but only for men’s and not women’s faces.
“We all make lots of judgements about people just by looking at them. Some of these judgements are very accurate – for example, we are >99.9% accurate at judging whether a face is male or female, even when we can’t see the hair, makeup, jewelry, facial hair etc. Other judgements, such as people’s personality traits, seem much less obvious. Our research suggests that at least some of these judgements are accurate,” Stephen told PsyPost.
“The main caveat is that we don’t know what the physiological mechanism is yet,” Stephen noted. “How exactly is our sociosexual orientation reflected in our faces? We suspect that it may have something to do with testosterone levels – people with higher testosterone levels look more masculine, and tend to express more masculine personality and behavioral traits. This would also go some way to explaining why it is only in the male faces. However, we don’t have testosterone measurements for the people in our study, so we can’t know for sure yet.”
The findings don’t mean that you should throw out the old adage “don’t judge a book by it’s cover,” Stephen added.
“While this study suggests that there may be some truth to our first impressions, we can get a lot more information about people’s personalities by speaking to them and observing how they behave,” he explained. “So I wouldn’t recommend making snap judgements about people just from how they look!”
The study, “Facial shape provides a valid cue to sociosexuality in men but not women“, was authored by Joseph C. Antar and Ian D. Stephen.