Georgio Coricelli of the University of Southern California led a multinational team of researchers that measured activity in the regions of the brain associated with rewards and with social reasoning while participants in the study entered in lotteries.
The researchers found that the striatum, a part of the brain associated with rewards, showed higher activity when a participant beat a peer in the lottery, as opposed to when the participant won while alone. The medial prefrontal cortex, a part of the brain associated with social reasoning, was more activated as well.
Those participants who won in a social setting tended to engage in more risky and competitive behavior in subsequent lotteries.
"These findings suggest that the brain is equipped with the ability to detect and encode social signals, make social signals salient, and then, use these signals to optimize future behavior," Coricelli says in a statement.
In private environments, losing can more easily be life-threatening, so with no social support network in place, a bad gamble can spell doom, Coricelli says. On the other hand, in group environments, rewards tend to be winner-takes-all, Coricelli says.
Their study is published in the Proceedings of the National Academy of Sciences.