Science says you can only have 150 friends
You might have 1,345 friends on Facebook, but science says only 150 of those are for real.
Robin Dunbar is an anthropologist at Oxford University and as part of his research he wanted to know the maximum number of stable friendships a human being can comfortably maintain.
Dunbar describes the level of most of these relationships as ‘‘the number of people you would not feel embarrassed about joining uninvited for a drink if you happened to bump into them in a bar’’.
Research by Facebook reveals that the average number of ‘‘friends’’ per Facebook user is about 130, although the number of active friends ranges between 50 and 150.
An anecdote that Dunbar relates concerns Bill Gore, the founder of the coat manufaturer, Gore-Tex. Gore observed that as his company got bigger it became less efficient since the empolyees were less likely to help each other.
Bill Gore decided that the maximum number of people in any of his factories should be 150.
The number 150 cropped up again when Dunbar was looking through the Domesday Book; he noted that the average population of the medieval village in England and Wales was 150.
The Domesday Book was the result of a survey commissioned by William the Conqueror in 1085 of the population of large parts of England and Wales.
It turns out the average population of neolithic villages was also 150; the same is true for all early hunter-gatherer societies, from African bushmen to Native American Indian tribes. The average number of soldiers in a company in a modern army is 180 – again, in the right ball park.
Dunbar set out to establish what was significant about the number 150. He suspected it had something to do with the human brain, so he plotted brain size in several species of monkeys and apes, versus the number of individuals in their groups and found that the bigger the brain of a species, the larger the group is.
The size of a group of monkeys is important, it has to be big enough to provide a survival advantage but not so big that it becomes chaotic.Dunbar plotted the size of the human brain on his graph and extrapolation revealed that the predicted size of a human group is 150.
He concluded that the reason that the average person has a maximum number of 150 acquaintances, is because that is the limited by brain size. Neuroimaging studies back this up.
The key region of the brain involved in social bonding is the connection between the part just above your eyes and the part of the brain just behind your ears.
These regions help you to understand what other people are thinking. This information highway has a limit of about 150 connections. The size of this connection can be progressively increased until your early twenties, after that, your limit has been reached for life.
Your friends and acquaintances can be visualized as a hierarchy of concentric circles decreasing in size from say, 150 to 100 to 50 to 25 to 10 to a core of 5. This core of approximately 5, represents your closest friends.
The social bond between you and your closest friends is strongest because you invest the most time in these relationships. Dunbar estimates that of the total time you invest in your friends, 75% is spent on just the inner circle of 10 to 5 friends.
Monkeys form bonds through grooming, the more time two monkeys spend grooming each other, the stronger the bond. If you don’t invest the time, the quality deteriorates.
If you form a romantic relationship you’ll drop a friend, in other words a romantic relationship costs a friendship – a friend from the inner circle. Research also shows that females are much better at maintaining relationships with distant friends.
This is backed up by Facebook who report that 2/3 of their traffic is from females. They are also good at strengthening their bonds by talking with each other.
Talking doesn’t work for males nearly so well. Activities - ‘‘doing stuff’’ such as sports is much more effective at strengthening social bonds between males.
The limit to the number of friends a human can cognitively accommodate is now referred to as Dunbar’s number.