A yellow dot in the brain seems to be the seat of altruism — and its opposite, selfishness — in the brain.
A new study, published in the July 12 issue of the journal Neuron, found the spot — called the temporoparietal junction — by asking 30 participants to play a money game in the lab. The players were given a small amount of money to split between themselves and an anonymous person.
Some of the participants hogged all the money for themselves, while others gave some away to the anonymous person they were playing with. When the researchers looked at their brains, they saw that people who behaved selfishly, and saved all the money for themselves, had less gray matter in the temporoparietal junction and those who were more giving had more gray matter.
The temporoparietal junction isn't a new discovery: It's previously been implicated in decision making. Disruptions in this area impact our ability to make decisions, previous studies have shown. It's also been linked to empathy, the ability to put yourself in someone else's shoes.
While the researchers, led by Ernst Fehr at the University of Zurich, say this is a good indication that this area of the brain has something to do with altruism, it's tough to tell if the size of this brain area is determined by genetics.
"These are exciting results for us. However, one should not jump to the conclusion that altruistic behavior is determined by biological factors alone," Fehr said in a statement from the university. Training could also play a role by beefing up this area, which is why we need to teach toddlers to share their toys.