From Science:
Giving feels good.
The brain’s reward center lights up on an MRI image when subjects give money to charity. You don’t need to donate to charity to feel all warm inside. Researchers have found that even when money is taken from some people involuntarily, they feel good about the transaction, as long as the funds go to a good cause. The findings may force economists to rethink just what guides our response to taxes and other financial decisions.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.
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