Thirty years ago, Robin Dunbar theorized humans can maintain a friendship group of 150 people, with five intimate friendships. Despite many attempts to challenge the theory, Dunbar's Number has stood the test of time. Backed by neuroscience and statistics, Robin Dunbar explains why his theory still prevails.
Researchers say during group problem-solving tasks, components of the "social brain" are co-activated, but they do not increase their coupling during cooperation as would be suggested by a holistic network.
Researchers propose the human brain is disproportionately large as a result of sizing one another up in large cooperative social groups.