Trust is indispensable in friendship, love, families and organizations, and plays a key role in economic exchange and politics.
In the absence of trust among trading partners, market transactions break down. In the absence of trust in a country's institutions and leaders, political legitimacy breaks down.
Much recent evidence indicates that trust contributes to economic, political and social success.

Little is known, however, about the biological basis of trust among humans.

Researchers at the University of Zurich in Switzerland showed that intranasal administration of Oxytocin, a neuropeptide that plays a key role in social attachment and affiliation in non-human mammals, causes a substantial increase in trust among humans, thereby greatly increasing the benefits from social interactions.

The effect of Oxytocin on trust is not due to a general increase in the readiness to bear risks. On the contrary, Oxytocin specifically affects an individual's willingness to accept social risks arising through interpersonal interactions.

In an experiment scientists found that people playing an investment game were more likely to trust others if they inhaled a nasal spray that contained oxytocin.
In the game, people acting as "investors" were given money-tokens that they could in turn give to "trustees."
Handing a token to a trustee quadrupled its value. The catch: trustees didn't have to share any of the proceeds with the investors. Still, scientists found that investors who had inhaled Oxytocin, were more likely to give up their tokens.

These results suggests an essential role for Oxytocin as a biological basis of prosocial approach behaviour.

Source: Nature, 2005


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