Women appear to be able to judge a man's faithfulness based on his facial features, according to University of Western Australia researchers.
Women use facial masculinity as a cue, with more masculine-looking men perceived as –– and more likely to have been –– cheaters.
The researchers recruited 34 heterosexual men aged between 17 and 48 and 34 heterosexual women aged between 17 and 45 to participate in the study.
They were shown photographs of 189 Caucasian men who had revealed to researchers whether they had cheated in the past. The participants were asked to rate photos of the opposite sex depending on perceived faithfulness and trustworthiness.
They found women "assessed men's unfaithfulness with modest accuracy" and that the more masculine a man's face, the more likely he was to have been a cheater.
But men did not seem to have the same cheater radar.
"Impressions of sexual faithfulness from faces have a kernel of truth, at least for women, and they may help people assess the quality of potential mates about whom they have minimal behavioural information," wrote lead author Dr Gillian Rhodes.
"Our results demonstrate that accurate judgements of unfaithfulness can be made from the face alone, in the absence of behavioural cues."
Dr Rhodes pointed out that it is in women's nature to seek a faithful partner in order to reduce the risk of having to rear children alone.
"Trust is particularly important in the context of sexual relationships and mate choice. There are substantial costs associated with choosing unfaithful
partners," she said.
"Men with unfaithful partners risk raising another man's child, and women with unfaithful partners risk losing some or even all parental and other resources to competitors."
Now the researchers would like to extend the study to older age brackets and different ethnicities.
The study was published in the journal Biology Letters.