Women can predict a male cheater just by looking at his face, a new study, by the University of Western Australia, has found.
It is the first study of its kind to successfully link impressions of unfaithfulness with face types, showing that "accurate judgements of unfaithfulness can be made from face alone, in the absence of behavioural cues" said its authors. They found that men were not able to pick unfaithful women by judging their faces alone.
Heterosexual participants, aged between 17 and 48, were asked to judge the faces of nearly 200 neutral-faced, opposite-sex strangers. They were shown colour photographs of the strangers for three seconds and asked to rate them on perceived faithfulness and trustworthiness.
Around half of the people photographed had reported cheating or poaching (having intercourse with a person who was in a relationship), and it was found that female participants were better at detecting these people.
"Women's rating of men's unfaithfulness showed small-moderate correlations with men's past unfaithfulness," they said. The men's ratings, on the other hand, "provide little evidence for accuracy in men's assessments of female unfaithfulness."
Only 38 per cent of women, compared to 77 per cent of men, got their assessments wrong. The authors suggested that the men's "poor performance could reflect lack of valid infidelity cues in female faces and/or men's insensitivity to such cues."
Such cues, they say, are important because of the "substantial costs associated with choosing unfaithful partners. These costs include the risk of men raising another man's child and women losing the parental support and resources to 'competitors.'
"We routinely form impressions of people from their faces, and these impressions sometimes contain a kernal of truth," the study's authors said. "Impressions of trustworthiness are central to interpersonal relationships, but their accuracy remains contentious."
While previous studies have shown that our ability to judge another person's trustworthiness based on their face is "slightly above chance" and that feminine-looking men are seen as less likely to cheat, generally speaking, we struggle to predict a person's behaviour by their appearance, the study's authors said.
But, their findings, which will be published in this week's Royal Society Journals, reveal that "facial masculinity mediated women's accuracy."
Masculine-looking men were accurately rated as more likely to be unfaithful and have a sexual history of being unfaithful. Interestingly, attractiveness did not play a part in the women's judgements. In fact, the female participants rated attractive men as being more trustworthy, "perhaps reflecting an attractiveness halo effect," the authors hypothesised.
Attractive, feminine-looking women were also rated as more trustworthy, however, they were also seen as more likely to be unfaithful by the men. This was despite "there [being] no evidence that they were."
"Our results add to the evidence that face perception is adaptively turned to cues that signal mate quality," said the authors.