According to a study published in Nature Neuroscience , the larger a person's brain amygdala, the greater the number of friends and family they interact with . Using MRI scanners, the study authors have been able to demonstrate that this relationship between the size of the amygdala and the size of an individual's social network occurs at any age and in both sexes.
According to Lisa Feldman Barrett, a researcher at Massachusetts General Hospital and Harvard Medical School in Boston (USA) and co-author of the study, this is because the amygdala – an almond-shaped structure located in the deep brain – contains a network of neurons that is essential for socialization . For example, this network helps to recognize if someone is a stranger or known, if he is a friend or an enemy. In addition, previous studies had already shown that "primates that live in larger social groups have the largest amygdala," according to Feldman.
