The scientists gave 19 women participants $100 and then scanned their brains with functional magnetic resonance imaging (fMRI) as they watched their money go to the food bank through mandatory taxation, and as they made choices about whether to give more money voluntarily or keep it for themselves.via Science Daily and CNN
Researchers found that two evolutionarily ancient regions deep in the brain -- the caudate nucleus and the nucleus accumbens -- fired when subjects saw the charity get the money. The activation was even larger when people gave the money voluntarily, instead of just paying it as taxes. These brain regions are the same ones that fire when basic needs such as food and pleasures (sweets or social contact) are satisfied.
"The surprising element for us was that in a situation in which your money is simply given to others -- where you do not have a free choice -- you still get reward-center activity," said Ulrich Mayr, a professor of psychology. "I don't think that most economists would have suspected that. It reinforces the idea that there is true altruism -- where it's all about how well the common good is doing. I've heard people claim that they don't mind paying taxes, if it's for a good cause -- and here we showed that you can actually see this going on inside the brain, and even measure it.