Contrary to popular belief men may well have the edge over women when it comes to intuition, research suggests.
Spot the difference... real (left) and fake (right)
Asked to separate fake and genuine smiles, men were correct 72% of the time, compared with 71% for women.
Volunteers were also asked to rate how intuitive they thought they were, with 80% of women rating themselves highly intuitive compared with 58% of men.
The University of Hertfordshire asked about 15,000 people to look at smiling faces and pick out the "real" grins.
The gap was widest when the participants were asked to look at faces of the opposite sex.
Men spotted 76% of women's fake smiles, while women only identified 67% of men's false smiles.
More in touch?
Research leader Professor Richard Wiseman, of the university's psychology department, said the findings questioned the notion of female intuition.
"Some previous research has found evidence for female intuition, but perhaps over time men have become more in touch with their intuitive side," he said.
And again... real (left), fake (right)
The study was conducted online and at events organised for the Edinburgh International Science Festival.
Participants were asked to complete a short questionnaire on intuition, allowing researchers to examine the types of people who are especially good at recognising emotions in others.
Certain parts of each face were masked in the pictures, to help discover which provide most information.
It suggested genuine smiles involve the muscles around the eyes, producing crows' feet around the corners, whereas a fake grin only involves the mouth.