Men about to play a financial game were shown images of sexy women or lingerie and were found more likely to accept unfair offers than men not been exposed to the sexually stimulating images.
The researchers think that the sexual cues distract the men's thoughts and thus preventing them from focusing on their task, and particularly so among those with high natural testosterone levels.
The research team gave 176 heterosexual male student volunteers aged 18 to 28 financial games to test their fair play but first, half of the men were shown sexual images of some kind.
One group of 44 men were given pictures to rate; some were shown landscapes while the others were shown attractive women and another group, of 37 men, were asked to assess the quality, texture and colour of a bra or a t-shirt.
A third group of 95 were shown pictures of elderly women or of young models.
Each group was then paired up to play a game involving money, which was designed as a laboratory model of hunting or food sharing situations.
The men's performance in the tests demonstrated those who had been exposed to the "sexual cues" were more likely to accept an unfair offer than those who were not.
Comparing the length of the men's index finger compared to their ring finger also tested the testosterone levels in the men and if the ring finger is longest, it indicates a high testosterone level.
The researchers discovered that men in the study who had the highest levels of the male hormone performed worst in the test, and suggested it is because they are particularly sensitive to sexual images.
Dr Siegfried DeWitte, one of the research team who worked on the study, said: "We like to think we are all rational beings, but our research suggests ... that people with high testosterone levels are very vulnerable to sexual cues."
The researchers are conducting similar tests with women volunteers but so far, they have failed to find a visual stimulus, which will affect their behaviour in a similar way as the men reacted.
