The size of social networks | Primates on Facebook | The Economist

Extrapolating from the brain sizes and social networks of apes, Dr Dunbar suggested that the size of the human brain allows stable networks of about 148. Rounded to 150, this has become famous as the Dunbar number

The rise of online social networks, with their troves of data, might shed some light on these matters. So The Economist asked Cameron Marlow, the “in-house sociologist” at Facebook, to crunch some numbers. Dr Marlow found that the average number of “friends” in a Facebook network is 120, consistent with Dr Dunbar’s hypothesis, and that women tend to have somewhat more than men. But the range is large, and some people have networks numbering more than 500, so the hypothesis cannot yet be regarded as proven.

This makes one wonder about whether or not social networks give us greater power to navigate social landscapes. Or whether enable us to waste more time with more people...