17/06/2011 14:55 BST | Updated 22/05/2015 10:12 BST

You Can't Put A Price On A Smile - Until Now

You can't put a price on a smile, so the old saying goes. But researchers at Bangor University have done just that, calculating that a smile is worth exactly one third of a penny – and that it's a form of "social currency" that people will pay for.

prince-william-kate-middleton-smile Which type of smile is Kate Middleton's? Photo: PA

The psychology department team designed an experiment to measure people's responses to two types of smile: the genuine smile – those that produce laughter lines at the sides of our eyes - and the polite smile – those that don't. In the experiment, students were invited to play a game against computerised "opponents" who smiled either genuinely or politely and had either higher or lower chances of winning money. As the game went on, participants were asked to choose their opponents, allowing researchers to work out how valuable they found each type of smile.

They found that people preferred to play against opponents with genuine smiles – even when that meant they were less likely to win. "Our participants, all university students, are usually highly motivated to earn money," said Danielle Shore, lead author of the research. "The fact that they chose opponents who were less likely to pay out was a big surprise."

So what are the implications of these findings? That smiling pays. "Genuine smiles might help people see eye-to-eye during interactions," says Shore. "People who often make genuine smiles may have an easier time convincing others to adopt their goals."