You might think that good-looking men have every advantage in life.

But a new study suggests being handsome may not always work in a man's favour – at least when it comes to his career.

The research claims that attractive men are less likely to be given a job in a competitive workplace because they intimidate bosses.

'It's not always an advantage to be pretty,' says Marko Pitesa, an assistant professor at the University of Maryland. 'It can backfire if you are perceived as a threat.'

Interestingly, in Pitesa's study, it was male attractiveness in particular, rather than female beauty, that made the most difference.

If the interviewer expected to work with the candidate as part of a team, then he preferred good-looking men.

However, if the interviewer saw the candidate as a potential competitor, the interviewer discriminated in favour of unattractive men.

In the first experiment, 241 adults were asked to evaluate fictional job candidates based on fake qualifications and experience, in an online setting.

Men evaluated men and women evaluated women. Interviewers were primed to either think of the candidate as a future co-operator or competitor, and they were given a computer-generated headshot that was either attractive or unattractive.

'Kind of attractive and average, maybe slightly below average,' Pitesa clarifies - no supermodels.

A second experiment involved 92 people in a lab. They were asked to evaluate future competitors or partners in a quiz game, based on credentials that included sample quiz answers, and they saw similar headshots.

The patterns of discrimination based on perceived self-interest was the same.

Another test opened up to include men interviewing women and women interviewing men.

There was still a preference to cooperate with the attractive man and compete against the unattractive man.

A final experiment used photographs of actual European business school students, vetted for attractiveness, and found the same pattern.

The results suggest that interviewers were not blinded by beauty, and instead calculated which candidate would further their own career.

'The dominant theoretical perspective in the social sciences for several decades has been that biases and discrimination are caused by irrational prejudice,' Pitesa says.

'The way we explain it here, pretty men just seem more competent, so it is actually subjectively rational to discriminate for or against them.'

On a deeper level, she adds, the behaviour remains irrational, since there's no evidence that a real link exists between looks and competence.