The "love" hormone linked to feelings of sexual pleasure, bonding and maternal care also appears to help us recognise familiar faces, Swiss researchers said on Tuesday.
Men given oxytocin - involved in nursing and childbirth - more accurately recalled images of familiar faces but the hormone did not help them recognise inanimate objects, Peter Klaver of the University of Zurich and colleagues said.
Their findings published in The Journal of Neuroscience suggest the hormone somehow strengthens the brain's neural networks involved in social memory and may have implications for conditions such as autism, researchers said.
"The study highlights the parallels in social information processing in mice and man, and adds further support to the notion oxytocin plays a critical role," Larry Young, an expert on oxytocin at Emory University in Atlanta, who was not involved in the study, said in a statement.
Implications for autism
Oxytocin was known for years to be involved in labour and it is the hormone that stimulates the production of milk for breastfeeding. Animal studies suggest it can help in bonding between mother and child and between mates.
"This has important implications for disorders such as autism, where social information processing is clearly impaired."
Only in recent decades has it been found to have a function in men - in sexual arousal and function.
Klaver and colleagues showed 44 men pictures of faces and inanimate objects that included sculptures, houses and other images. Half the volunteers received an oxytocin nasal spray and the rest got a placebo.
Better face recognition
The researchers found that men who used the oxytocin spray more accurately recognised the faces they had seen before than did those in the placebo group. The hormone made no difference for the other pictures, Klaver said.
Further analysis also showed the hormone made it less likely for people to mistakenly characterise unfamiliar faces as familiar, the researchers said.
"It is important to understand that social recognition can be improved by such hormones," Klaver said in a telephonic interview.
(Reuters Health, January 2009)
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