Monday, 9 September 2013
Why You Can Have No More Than About 150 Real Friends
So you’re proud that you have 500, or maybe even 1000, friends on Facebook? Sorry to tell you, but you probably have far fewer, if we are to believe Robin Dunbar, a professor of evolutionary anthropology at Oxford University in the United Kingdom. As few as 150, in fact: this is the famous “Dunbar’s number”, a limit of about 150 people above and beyond which it is supposed to be impossible to maintain true friendships.
But what is a friendship? You know when you have one, but it is not something that is easy to define. French essayist Michel de Montaigne said that he loved his best friend, Étienne de la Boétie, “because it was he, because it was I”. For Dunbar, friendship is an emotional reaction that arises out of a personal history. And one important criterion for true friendship is that a true friend will readily do you a favour if you ask. But why should the maximum number of people with whom you can have such a special relationship top out at about 150?
For two main reasons, says Dunbar. First, if you tried to keep up to date on the lives of more than 150 people, the cognitive burden would become too heavy. Dunbar derived his number from a correlation that he found between the size of the cortex in the brains of primates and the number of individuals in the groups in which they live. Dunbar then made an extrapolation based on the size of the human brain, from which he obtained this value of about 150. And this number just happens to correspond to the estimated size of the communities of our hunter-gatherer ancestors and to the average size of villages in pre-industrial societies.
The second reason that you can have no more than 150 real friends is that if you try to make even a minimum investment in more than 150 relationships, you start to run out of time. Online social networks are great for sharing interesting newspaper articles or telling the world what you’re cooking for dinner. But to maintain a real friendship takes something more: verbal, visual, and physical contact, all of which require time.
Why is this so? Because we humans are the product of a very long evolutionary history, over which our social structures developed through these very concrete mechanisms, which are now deeply ingrained in our biology and hence in our psyches. One good example of such a mechanism is another key concept advanced by Dunbar: gossip, which plays such a large part in our conversations. According to Dunbar, gossip in humans serves a function analogous to that of social grooming in other primates—an activity that takes place only among a limited number of friends.
So when someone says that they have over 200 “friends”on Facebook, it would probably be more accurate to say that they have over 200 acquaintances, or over 200 spectators viewing their private lives.