FACEBOOK users used to have more friends. Social networking sites pursue a commercial strategy of trying to “friend” as many people as possible. However, at some point around 2007, users began to wonder who the people they had befriended were. Then someone pointed out to us that he can only manage about 150 relationships at any given time. A series of cullings of “friends” followed, and the number 150 has since become known as “Dunbar's number.” Thank you, Facebook!
Modern technology may have given it some notoriety, but Dunbar's number has roots in evolutionary biology. Humans are a highly social species, but we don't easily manage relationships, and like other primates, the size of our social networks is limited by the size of our brains. My research 20 years ago revealed that this means we are unable to meaningfully interact with more than about 150 other people. No matter how social you are, that's your limit. In this respect we are all the same. However, recent research on friendship has revealed some interesting individual differences.
My colleagues and I explore how much time people spend cultivating different members of their social networks, how friendships form and disappear, and what we look for in a friend. I have made some eye-opening discoveries about it. What really surprised us was that each person has a unique “social fingerprint,” or idiosyncratic way of allocating social effort. This pattern is completely independent of who is in your friendship circle at any given time. But it can reveal a lot about your own identity and even affect how well you can cope with social restrictions…
Source: www.newscientist.com