The neuropeptide oxytocin is released during childbirth, suckling, touch and orgasm, suggesting that it might have a 'pro-social' function. This idea was strengthened by a recent study in Nature, which showed that an oxytocin nasal spray caused people playing a 'trust' game to retain their trust in a stranger who was looking after their money, even though this trust was violated on many occasions. At the same time, the oxytocin spray decreased activity in the amygdala and the caudate nucleus, brain areas that are involved in the regulation of fear and decision making, respectively.

“We now know ... what exactly is going on in the brain when oxytocin increases trust,” says lead researcher Thomas Baumgartner of the University of Zürich, Switzerland. “It seems to diminish our fears.” ( BBC News , 21 May 2008.) As humans are typically averse to taking social risks, “...a little bit of oxytocin may facilitate carrying on relationships with others,” according to Mauricio Delgado, a neuroscientist at Rutgers University in Newark, New Jersey. ( ScienceNOW , 21 May 2008.)

How people in real-life situations develop and retain trust in others is another question, however. “They certainly don't do it by spraying stuff up each other's noses,” says Paul Zak of the Center for Neuroeconomics Studies at Claremont Graduate University in California. ( Science News , 21 May 2008.)

Nevertheless, the findings have implications for understanding mental disorders in which deficits in social behaviour are observed and “...could provide a bridge for potential clinical applications,” thinks Delgado (BBC News). An oxytocin spray might help people with a social phobia or autism. “Autistic people also have a fear of social situations and have problems interacting, so it is very likely that oxytocin could help,” says Baumgartner. “This hormone seems to play a very specific role in social situations so might be able to improve autism.” (BBC News.)