The glow of giving

My friend J enjoys paying for the person behind her in line at the Starbucks drive-through to the everlasting delight of her daughters. If she carried a function MRI machine in her van, a recent study out of Oregon(1) suggests that we could see the girls' brains light up with philanthropic pleasure.

This neuroeconomic study stuck volunteers in just such a machine and scanned their noggins while they played a 'dictator game.' The subjects received $100 and then made decisions about whether or not to donate money to the game's food bank.

The investigators correlated the subjects' self-reported satisfaction of giving with activity in their ventral striatum, a structure deep within the brain known to produce a feel-good sort of reward response. The area was fired up whether or not the giving was voluntary vs. mandatory taxed transfers, but glowed hotter when the altruism came from the heart and not the government.

The researchers dubbed this response the warm-glow motive. This may explain, they say, the economic puzzle: If money is a good, why are people willing to give it away?
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Harbaugh WT et al. Science 316 (2007)1622-1625.