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June 22, 2007
Brain Imaging Reveals Joys of Giving
The old adage “It’s better to give than to receive” may have a biological basis. A new study found that the brain's pleasure centers became activated as people decided to donate part of a new stash of money to charity, rather than keeping it all for themselves. The findings may shed light on why some people contribute to the public good, even at a personal cost.
Researchers at the University of Oregon took advantage of an advanced brain imaging technique known as functional magnetic resonance imaging (fMRI), which shows when specific regions of the brain are activated. Their study was supported by NIH's National Institute on Aging (NIA) and the National Science Foundation.
At the start of the experiment, 19 women received $100 and were told they could keep whatever money remained at the end of the session. They then lay in an fMRI scanner for about an hour, while a computer screen displayed a series of possible money transfers to a local food bank. About half of the proposed transfers were voluntary — participants could decide whether to accept or reject the donation. In other cases, the proposed transfers were required, similar to a tax. Occasionally, additional money was unexpectedly added or taken away from either the woman's or the charity's account.
As described in the June 15, 2007, issue of Science, the brain scans showed that three very different situations — receiving money, seeing money go to a good cause or deciding to donate money — all activated similar pleasure-related centers deep in the brain.
“To economists, the surprising thing about this paper is that we actually see people getting rewards as they give up money,” said Dr. William T. Harbaugh, professor of economics and first author of the study. “On top of that, people experience even more brain activation when they give voluntarily.” The higher brain response to voluntary giving might correspond to the “warm glow” people reportedly experience when they’ve donated money to a good cause.
The researchers were also able to use fMRI to classify people as either egoists or altruists, depending on whether their brains responded more a money influx to themselves or to the charity. The altruists, with their stronger responses to charitable donations, gave money to the food bank nearly twice as often as the egoists. Dr. Ulrich Mayr, one of the study’s authors, said, “Based on what we saw in the experiments, we can use this classification to predict how much money people are willing to give when the choice is theirs.”
Although voluntary giving led to greater pleasure activation in the brain, it didn’t create a financial windfall for the food bank. Participants rejected more than half of the voluntary transfers and, overall, the charity received 10% less money from voluntary donations than from the tax-like mandatory contributions.
— by Vicki Contie