Lets start with the monkeys...
I've just been watching David Attenborough's 'Funky Monkeys' documentary on TV. I learned that monkeys brain sizes directly correlate to the size of their social group, or social network.
One explanation is that the larger groups, (for example a hundred monkeys living together) are more complex, therefore a monkey must be exceptionally smart and politically savvy to rise to become an effective group leader. Groups that become unmanageably large split into smaller groups. Scientists can accurately determine the size of the monkey's social group directly from its brain size, before even knowing what kind of monkey it is.
How does this correlation between brain size and social network size relate to humans?
According to Dunbar's number, the size of human social networks has been approx 150 for at least tens of thousands of years (incl. today's online groups). Our brain sizes have also stayed much the same. Dunbar theorized that "this limit is a direct function of relative neocortex size, which limits group size ...the limit imposed by neocortical processing capacity is simply on the number of individuals with whom a stable inter-personal relationship can be maintained." David Wong wrote a pretty entertaining article about it.
However some humans social networks are much larger than average - and some people care about far more than 150 people. Based on the thinking in David Wong's article, that would be a good thing!
One factor that could explain this is that some people are extroverts (as opposed to introverts), so they might naturally hold more information about 'people' in their brains (instead of other kinds of knowledge).
Another idea is that some humans have 'outsourced' a large quantity of information (potential extra brain size?) to collaborative information storing and sharing facilities on the internet (e.g. storing / relying on knowledge in Wikipedia instead of trying to remember it in our heads, or storing information about people in databases or sites such as Facebook). Might this be our way of evolving faster than standard biological evolution (our brain size) permits?
Yet another factor might be that some people choose to believe in all people being equally important, even the people we don't yet know. In other words, choosing to see the humanity in, and therefore have consideration for, every person in the world.
So, I am pondering whether the combination of: a. an individual's biological brain size/intelligence + b. their personality type (extrovert or introvert) + c. the amount they leverage the 'global outsourced intelligence' of the internet + d. the degree to which they choose to be considerate of every human correlate to the size of their social network?
What do you think? Are any assumptions wrong/debatable? What other factors would be involved? Wouldn't it be good if humans perceived all humans as being a broader, but equally important part of their network? Will tools like Facebook and LinkedIn help?