The kindness HORMONE

Why are some of us more humane than others?

Why are some of us more humane than others?
Behind the thousands of acts of kindness,kind-of kindness and not-as-nakedly-venal-as-I-could-have-been kindness that make human society possible,lies a hormone called oxytocin. It is the small,celebrated peptide hormone our brain supplies and which helps lubricate our every prosocial exchange. Scientists have long known that oxytocin plays essential physiological roles during birth and lactation,and animal studies have shown that the hormone can influence behaviour too,prompting voles to cuddle up with their mates,for example,or to clean and comfort their pups. Now,a raft of new research in humans suggests that oxytocin underlies the twin emotional pillars of civilised life,our capacity to feel empathy and trust.

Reporting this month in The Proceedings of the National Academy of Sciences,researchers found that genetic differences in peoples responsiveness to the effects of oxytocin were linked to their ability to read faces,infer the emotions of others,feel distress at others hardship and even to identify with characters in a novel. I came into this research as a big sceptic, said Sarina M. Rodrigues of Oregon State University,an author of the new report,but the results had me floored.

Oxytocin may also be a capitalist tool. In a series of papers that appeared in Nature,Neuron and elsewhere,Ernst Fehr,director of the Institute for Empirical Research in Economics at the University of Zurich,and his colleagues showed that the hormone had a remarkable effect on the willingness of people to trust strangers with their money. In the Nature study,58 healthy male students were given a single nasal squirt of either oxytocin or a placebo solution and,50 minutes later,were instructed to start playing rounds of the Trust Game with each other,using monetary units they could either invest or withhold.

The researchers found that the oxytocin-enhanced subjects were significantly more likely than the placebo players to trust their financial partners: whereas 45 per cent of the oxytocin group agreed to invest the maximum amount of money possible,just 21 per cent of the control group proved so amenable. The oxytocin boost didnt simply make subjects more willing to take risks and throw their money around. When participants knew they were playing against a computer rather than a human,there was no difference in investment strategy between the groups. Trust,it seems,is a strictly wetware affair.

Yet the hormone doesnt turn you into a sucker. In the November 1 issue of Biological Psychiatry,Simone Shamay-Tsoory of the University of Haifa and her colleagues reported that when participants in a game of chance were pitted against a player they considered arrogant,a nasal spritz of oxytocin augmented their feelings both of envy whenever the haughty one won and of gloating when their opponent lost.

As a rule,oxytocin is a joiner not a splitter. Analogues of the molecule are found in fish,perhaps to help facilitate the delicate business of fertilisation,by inhibiting a fishs natural tendency to flee from other fish. The more elaborate grew the social demands,the more roles oxytocin assumed,reaching its apotheosis in mammals. If youre going to give birth to a litter of needy young,why not let the same signal that helped push those mewlers into the world give you tips on their care and feeding? And if youre a human,bent on turning everything into an extended family affair,here is oxytocin again to cheerlead and teleprompt. C. Sue Carter of the University of Illinois at Chicago suspects that the association between the hormone and childbirth long kept scientists from taking it seriously. Now that its been brought into the world of economics and finance, Dr Carter said,suddenly its very hot.

Oxytocin acts as a hormone,travelling through the bloodstream to affect organs far from its origin in the brain,and as a kind of neurotransmitter,allowing brain cells to communicate. Unlike most neurotransmitters,oxytocin seems to deliver its signal through just one receptor,one protein designed to recognise its shape and shudder accordingly when clasped; dopamine and serotonin,by contrast,each have five or more receptors assigned to their care. Yet the precise contours of oxytocins hardworking receptor differ among individuals,to apparently noticeable effect.

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In their new study,Dr Rodrigues and Laura R. Saslow and Dacher Keltner of the University of California,Berkeley,looked at how two variants in the genetic code for the receptor might influence a persons capacity for empathy,as measured by a standard empathy questionnaire I really get involved with the feelings of the characters in a novel and a behavioural task called Reading the mind in the eyes. In it,participants looked at 36 black-and-white photographs of peoples eyes and were asked to choose the word that best described each subjects mood. Uneasy,defiant,contemplative,playful? In a related measure of oxytocins presumed calming effects,subjects were also tested for how strongly they reacted to the stress of hearing a series of loud noises.

In their sample of 192 male and female college students,the researchers found that those carrying the so-called A version of the oxytocin receptor,which previous reports had associated with autism and poor parenting skills,scored significantly lower on the eye-reading task and higher on the stress-prone test than did subjects with the G variant of the receptor.
Were all different,and thats a good thing, Dr Rodrigues said. If everyone were gooey and lovey-dovey,it would be an obnoxious world.

_ Natalie Angier,NYT