The price of a genuine smile has been valued at around one third of a penny, scientists said today.

Researchers at Bangor University have placed an economic value on a smile in order to establish how the friendly gesture can affect decision making.

The relatively low value reflects the fact that people exchange 10 to 20 smiles in the course of a short interaction, said Danielle Shore, a PhD student and lead author of the research.

“If a salesperson gives you a genuine smile of pleasure, you will have a positive experience and be likely to buy a nicer product or more add-ons than you originally intended,” she added.

“Indeed, genuine smiles appear to act as a form of social currency, a valuable reward that people will pay to receive.”

The research team examined people’s responses to two types of smiles, genuine and polite.