Why some people are generous

12 November, 2007

Ever wondered why some people are more charitable than others? It could simply be because of the levels of a hormone in the brain.

A new study has suggested that those who give more to charity and are more kind to strangers have above-normal levels of the hormone oxytocin in the brain. This also means that tightfisted people have comparatively lower levels of oxytocin in their brain.

The study, conducted by Professor Paul Zak, a professor of economics and director of the Center for Neuroeconomics Studies at Claremont Graduate University in California, the United States, and colleagues revealed a “huge increase” in generosity linked to higher levels of oxytocin.

In the study, Professor Paul Zak’s team gave doses of oxytocin and a placebo to participants, who were then offered a decision on how to split a sum of money with a stranger who could accept or reject the split.

To their utter surprise, the researchers found that those given oxytocin offered 80% more money than those who were given a placebo.

According to the study, there is even evidence that, in American society, the levels of oxytocin in the brain are increasing, as annual levels of charity in the United States have gone up by 187% since 1954.

According to data available, in 2005, individuals in the United States donated $200 billion to charity, and over 65 million people volunteered to help charities. When asked why they spent their money and time to help strangers, 96% of them had said that they felt compassion toward others.

However, the researchers stressed, this phenomenon is not because genes responsible for high oxytocin levels are spreading or because people are inhaling the chemical. It is because “the hormone oxytocin is made at greater levels as a result of touching, receiving signals of trust from other people, or when presented by advertisers with an image that touches the heartstrings, such as a photograph of a poverty-stricken child.”

In the study, published in the November 2007 issue of the journal Public Library of Science, Professor Zak explains, “Oxytocin specifically and powerfully affected generosity using real money when participants had to think about another’s feelings. This result confirms our earlier work showing that oxytocin affects trust, but with a dramatically larger effect for generosity.”

The effect of the hormone oxytocin on generosity, Professor Zak added, is more than three times larger than what was observed in the work he published in Nature in 2005 with colleagues in Zurich, Switzerland.


That study had showed that people who inhaled an oxytocin nasal spray were more likely to trust a stranger with their cash – the trust with oxytocin going up by 17%. But, the latest study showed that generosity increased by 80% with oxytocin.

Professor Zak also cautions about the abuse of oxytocin. Says he, “Inhaling oxytocin has side effects: 20% of the men who take it get erections, and pregnant women who take it may get contractions. Besides, oxytocin sprays are unnecessary: con men, sales people and advertisers already know how to use powerful images to win over people.