Giving feels good.
The brain's reward center lights up on an MRI image when subjects give money to charity.

Credit: William T. Harbaugh

Can't Buy Me Altruism

By Adam Hinterthuer
ScienceNOW Daily News
14 June 2007

The behavior under the microscope is altruism, which refers to concern for the well-being of others. Sometimes this manifests as a "warm glow" associated with the act of giving. In that case, economists speculate, the act is not entirely selfless because the giver makes the donation in order to feel good. But economists have also proposed that not all warm glows are self-interested. Some people may have positive emotions wash over them just from witnessing good deeds. This is called "pure altruism," and it may be motivating society's biggest givers.

Now a group of neuroscientists and economists at the University of Oregon, Eugene, has teamed up to get inside the heads of charitable citizens. The researchers recruited 19 female students and placed them in magnetic resonance imaging (MRI) machines to monitor the caudate nucleus and the nucleus accumbens, ancient regions of the brain, which produce feelings of pleasure and fulfillment. Each student participated in an economic game centered on charitable giving. They first received $100 in cold hard cash and were told any money left at the end of the study was theirs to keep. They then learned about a local food bank that would benefit from any donations from their account.

The volunteers then watched a screen as a computer program decided what to do with their money. Sometimes students could choose whether to give to the food bank. Other times, the computer "taxed" their account, donating money automatically to the food bank. And, once in a while, money would magically appear, either in their account or in the food bank's coffers.

Most subjects experienced the "warm glow" effect after voluntarily giving money, but some were also wired for pure altruism. In this latter group, the pleasure zones of volunteers' brains lit up when the food bank received money, even if the volunteers were being taxed. More surprisingly, when these subjects saw the computer randomly place money into the account of the food bank, they had a stronger positive reaction than when their own funds suddenly increased. And this big mental reward paid dividends to the food bank. Students exhibiting pure altruist behavior ponied up twice as much money as their "warm glow"-only counterparts, the team reports tomorrow in Science. The findings should surprise economists, says co-author Ulrich Mayr, as they indicate that some people care more about money going to the public good than to themselves.

The paper has the potential to be a "landmark study" in neuroeconomics, says Brian Knutson, a neuroscientist at Stanford University in Palo Alto, California, because it shows that hard science can help answer social questions. Knutson says it would be nice to see follow up studies that look into the minds of groups such as males, or the poor, or people in other countries to see whether we're all neurologically rewarded by giving, or whether female college students are especially generous.

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