New York, May 27 (IANS): You may have known it all along but researchers have now proved that a smile indeed helps you strike a chord with a stranger and also maintain a good relationship with your partner.

It works because people are much more attuned to positive emotions when forming new bonds than they are to negative ones such as anger and sadness, the study said.

However, do not try to fake a smile, because people can recognise a sincere smile a mile away, said the researcher Belinda Campos from University of California, Irvine in the US.

"Our results provide evidence of the significance of positive emotions in social settings and highlight the role of positive emotions in the development of new social connections," Campos said.

The researchers conducted two studies to test the role that positive emotions play in relationships.

The first one tested how aware 66 dating couples were of their partners' positive emotions.

The researchers found that dating couples were able to quite accurately track their partners' positive emotions.

The second experiment looked at how attuned people are to positive emotions and if it helps them to form new social bonds.

This was done by assigning 91 women to watch six emotion-laden film clips in the company of either a roommate or a stranger.

People tended to feel closer to strangers who displayed positive emotions.

The results showed that people are much more aware of others' positive emotions than their negative ones.

The study was published in Springer's journal Motivation and Emotion.