People blessed with more symmetrical facial features, which are considered more attractive, are less likely to co-operate and more likely to selfishly focus on their own interests, says a new study.
Santiago Sanchez-Pages, who works at the universities of Barcelona and Edinburgh, and Enrique Turiegano, of the Universidad Autonoma de Madrid, base their claims on the "prisoner's dilemma" model of behaviour, played out under laboratory conditions.
Two players were each given the option of being a "dove" and co-operating for the greater good; or a "hawk", taking the selfish option, with a chance of gaining more if the other player chose "dove" and co-operated.
The subjects' faces were then analysed.
The study found that people with more symmetrical faces were less likely to co-operate and less likely to expect others to co-operate.
The two academics speculate that individuals with symmetrical faces are more self-sufficient and have less need for seeking the help of others.
"As people with symmetrical faces tend to be healthier and more attractive, they are also more self-sufficient and have less of an incentive to co-operate and seek help from others," the Guardian quoted them as saying.
"Through natural selection over thousands of years, these characteristics continue to the present day," they added.
The findings will be presented at the annual Nobel Laureate Meetings in Lindau, Germany, from 23 to 27 August.