Massage therapists are oftentimes described as helpful and empathetic—in other words, altruistic—but what explains extreme difference in individuals’ altruism?

It may all come down to variation in the size and activity of a brain region involved in appreciating others’ perspectives. The findings also provide a neural explanation for why altruistic tendencies remain stable over time.

“This is the first study to link both brain anatomy and brain activation to human altruism,” says senior study author Ernst Fehr of the University of Zurich, in a publisher’s press release. “The findings suggest that the development of altruism through appropriate training or social practices might occur through changes in the brain structure and the neural activations that we identified in our study.”

Individuals who excel at understanding others’ intents and beliefs are more altruistic than those who struggle at this task, the press release noted. “The ability to understand others’ perspectives has previously been associated with activity in a brain region known as the temporoparietal junction (TPJ). Based on these past findings, Fehr and his team reasoned that the size and activation of the TPJ would relate to individual differences in altruism.”

In the new study, subjects underwent a brain-imaging scan and played a game in which they had to decide how to split money between themselves and anonymous partners, according to the press release. Subjects who made more generous decisions had a larger TPJ in the right hemisphere of the brain compared with subjects who made stingy decisions.

The study, “Linking Brain Structure and Activation in Temporoparietal Junction to Explain the Neurobiology of Human Altruism,” was published by Cell Press in the journal Neuron.

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