Researchers have discovered that Oxytocin, a hormone well known for its role in helping mothers to bond with their babies during breastfeeding, is also involved in helping people recognise familiar faces.
The findings are the first time to shown the hormone in important in helping to remember social interaction.
"Recognising a familiar face is a crucial feature of successful social interaction in humans," said Dr Peter Klaver at the University of Zurich, the senior author of the new study, which was led by Ulrike Rimmele, PhD, at New York University. "In this study, we investigated for the first time the systematic effect of oxytocin on social memory in humans."
Dr Klaver and his colleagues had the study participants use a nasal spray containing either oxytocin or a placebo and then showed them images of faces and inanimate objects, including houses, sculptures, and landscapes.
Participants were given a surprise test when they returned the next day - they were shown some of the images they had seen the day before as well as some new ones and were asked to distinguish between images that were "new," images that they specifically "remembered" being show the previous day.
The volunteers who used the oxytocin spray more accurately recognised the faces they had seen before than did those in the placebo group.
Dr Larry Young at Emory University, an expert on oxytocin who was not involved in the study, which was published in the Journal of Neuroscience, said the results had wide implications.
He said: "This has important implications for disorders such as autism, where social information processing is clearly impaired."