Men are on their best behaviour and more likely to commit acts of generosity when there are attractive women in the vicinity, research has revealed.

What’s more, the more attractive the women, the more selfless acts the man will commit.

The researchers, led by Dr Wendy Iredale of Sheffield Hallam University and Mark Van Vugt of the VU University in Amseterdam and the University of Oxford, conducted two experiments.

In the first study, 65 men and 65 women with an average age of 21 anonymously played a game in which they could donate money via a computer program to a group fund, ScienceDaily reports.

The donations were selfless as the participant would not necessarily benefit from them but all other players would.

While playing the game, each participant was observed by either an attractive man or an attractive woman.

The study, published in the British Journal of Psychology, found that the male players did more good deeds when observed by the woman. But there was no parallel effect for the women. They did the same number of deeds regardless of the sex of the person observing them.

In the second experiment, groups of men were asked to make a number of public donations. When observed by an attractive female the number of donations not only increased but the men competed with each other.

Researchers said men instinctively changed their behaviour in the presence of attractive women to boost their chances of securing a mate by appearing kinder, the Telegraph reports.

Dr Iredale said: "The research shows that good deeds among men increase when presented with an opportunity to copulate. Theoretically, this suggests that a good deed is the human equivalent of the peacock's tail. Practically, this research shows how societies can encourage selfless acts."