Social brain hypothesis

An area of the brain associated with understanding the minds of others is larger in people who have bigger social networks .

The "social brain hypothesis" holds that the reason primates, including humans, have relatively large brains is that they need the processing space to cope with their complex social networks.

But humans range from loner to life of the party, and University of Oxford anthropologist Robin Dunbar and his colleagues wanted to know if there is a brain basis for these differences. To find out, they took anatomical scans of the brains of 40 volunteers using magnetic resonance imaging. The participants also completed some tests to determine how good they were at "mentalizing," or understanding another person's mental state. This process is similar to empathy but goes beyond understanding emotions to understanding another person's goals, needs and reasoning.