Researchers have found that part of the brain called the amygdala, a word derived from the Greek for almond, is larger in more sociable people than in those who lead less gregarious lives.
The finding, which held for men and women of all ages, is the first to show a link between the size of a specific brain region and the number and complexity of a person's relationships.
Those with the smallest amygdalas listed fewer than five to 15 people as regular contacts, while those with the largest amygdalas counted up to 50 acquaintances in their social lives. Older volunteers tended to have smaller amygdalas and fewer people in their social group.
Writing in the journal, Nature Neuroscience, Barrett's team cautions that the finding is only a correlation, meaning they cannot say whether there is a causal link between the size of the amygdala and the richness of a person's social life. However, previous studies with primates show that those that live in large social groups also have bigger amygdalas. "People who have large amygdalas may have the raw material needed to maintain larger and more complex social networks," said Barrett . "That said, the brain is a use it or lose it organ. It may be that when people interact more their amygdalas get larger. That would be my guess.
"It's not that someone with a larger amygdala can do things that someone with a smaller amygdala cannot do. People differ in how well they remember people's names and faces and the situation in which they met them. Someone with a larger amygdala might simply be better at remembering those details," Barrett added.
Anyone got an MRI lying around?