Men may be able to tell how faithful a woman is based on her appearance alone, new research has suggested.

The study investigated whether sexual faithfulness could be accurately judged by only looking at the appearance of opposite-sex strangers.

“It is striking that men were able to show any accuracy from images alone after only a brief presentation, considering that accuracy in faithfulness judgments made from behavioural information is relatively poor,” the researchers from the University of Western Australia wrote in the study, published in PLOS One.

In two experiments, evolutionary psychologist Samantha Leivers and her colleagues, Leigh W. Simmons and Gillian Rhodes, found heterosexual men could choose the more faithful of two women from photographs alone.

However, the participants showed no accuracy in rating individual women, suggesting a man’s ability to detect a cheater based solely on her appearance is weak. It seems a comparison is needed to judge faithfulness.

The researchers used 34 pictures of heterosexual women between 20 and 42, along with information about whether they had cheated on a partner. The models were grouped into 17 pairs, with one woman who reported cheating on a partner two or more times and the other reporting never cheating on a partner.

The 43 participants were shown the photos of the pairs of women and asked to choose which of the two they thought was more faithful.

Another 29 participants were asked to rate each woman’s perceived trustworthiness.

The researchers found a relationship between perceived trustworthiness and accurate judgements of faithfulness.

They then conducted a second experiment with a new sample of 60 men to see if they could replicate their initial findings.

They found men were accurate in juding which of the two women had been more faithful 55 to 59 per cent of the time, suggesting men may be able to accurately judge

female faithfulness from looks alone.

“Our results provide the first evidence that such judgments can contain a kernel of truth”, the researchers wrote. “When asked to choose the more faithful women from pairs of images, men chose the woman who had not reported any [cheating behaviour] significantly above chance level.”

The researchers went on to suggest mechanisms enabling men to identify women who were likely to cheat could be evolutionarily advantageous in avoiding cuckoldry.