Members of the opposite sex can spot whether someone is after a one-night stand or something more permanent just by looking at their face, scientists said on Wednesday.
On men, a square jaw, large nose and small eyes are more likely to betray the look of lust than of love.
Women found men with softer features more likely to opt for commitment.
But the Durham University-led research found that while men can judge whether a woman is footloose-and-fancy-free or not, there is no common facial detail to explain it.
About 700 heterosexual people took part in the survey carried out by Durham, St. Andrews and Aberdeen universities.
In one study, 72 percent of the 153 participants correctly identified the sexual attitudes of a group of men and women in their 20s after being shown photographs or facial images.
Published in the journal "Evolution and Human Behaviour", the research also showed that women who were open to short-term sexual relationships were usually seen as more attractive.
VIA Reuters: How to identify the look of love... or lust
University of Aberdeen: Face
Guardian UK:Love at first sight just sex and ego, study says