January 24, 2010
Dunbar developed a theory known as “Dunbar’s number” in the 1990s which claimed that the size of our neocortex — the part of the brain used for conscious thought and language — limits us to managing social circles of around 150 friends, no matter how sociable we are. These are relationships in which a person knows how each friend relates to every other friend. They are people you care about and contact at least once a year.
Dunbar derived the limit from studying social groupings in a variety of societies — from neolithic villages to modern office environments. He found that people tended to self-organise in groups of around 150 because social cohesion begins to deteriorate as groups become larger. Dunbar is now studying social networking websites to see if the “Facebook effect” has stretched the size of social groupings. Preliminary results suggest it has not.
“The interesting thing is that you can have 1,500 friends but when you actually look at traffic on sites, you see people maintain the same inner circle of around 150 people that we observe in the real world,” said Dunbar. “People obviously like the kudos of having hundreds of friends but the reality is that they’re unlikely to be bigger than anyone else’s. “There is a big sex difference though ... girls are much better at maintaining relationships just by talking to each other. Boys need to do physical stuff together.”
Dunbar’s study is due to be published later this year.