Networking - a modern phenomenon?
You may all know about Dunbar's Number, which is based on the finding that the human brain tends to knock off work if asked to keep close track of much over 150 other people. Yet many young people in today's digital communication age have social networks much larger than this: some have literally thousands of friends on Facebook. Is this a really big change in human capacity? Are we seeing some kind of expansion, through technology, of the networking capacity of the human brain? The implications of this are startling, if you consider that social networks were extremely important in the recent "Arab Spring" and "Occupy" moments. It is also noteworthy that terrorist groups also use modern communications technology to keep in touch.
Now several new pieces of research have come out that touch on these questions. One is a study suggesting that Online network size is reflected in human brain structure and another adds to this by finding that the size of a person's orbital prefrontal cortex predicts their social network size!
For me, and many other people interested in human evolution, it is of interest to ask: is this a sign of a "sea-change" in the cognitive demands of human existence? Is this the beginning of the next phase in selection pressure on our species, with respect to cognitive function and overall intelligence? You might have seen some speculation along these lines in the recent material published on the role of the teenaged brain in human adaptability, nicely presented in documentary form in a recent episode of the Nature of Things, for instance. For those of you who cannot use this link, there are numerous studies now documenting the changes in cognitive systems, particularly the late growth of the prefrontal cortex, in humans, which explain much about teenage and young adult behaviour, including risk taking, emotional outbursts, and creativity.
It is also possible that these are aspects of human cognition that are very old, and were developed while most humans were still foragers. A recent study of foragers called the Hadza, who live in southeast Africa, mapping social networks, reveals a pattern very similar to that of modern electronic communications. Here you can see a short film showing these mapped networks, comparing those among the foragers with those seen in modern social networking media.