Dunbar is credited with theorizing that size of neocortex (area of the brain) in a given primate species, will dictate the optimal size of tribes/communities before they begin splitting into separate groups. He noted that the number can grow much larger when the environmental survival factors  (ie danger) are low and necessitate LESS social cohesion among the members. He developed the formula that uses brain volume, to predict what the mean group size (Dunbar number) should be for each species. In humans, the Dunbar # is roughly 148 people and anthropological research has verified that early hunter-gatherer groups would split into separate tribes at around 150 people.

The theory hypothesizes that for a given community to have a high chance of survival in a dangerous environment, the members of that group need to possess an accurate working sense of the trustworthiness, competence and social history of the other members. This number is essentially a measure of when “social cohesion” begins to break down, and Dunbar tells us that the majority of humans lose the ability to do well beyond about 150 relationships.

So, you ask, how does all this apply to the social web? Let me answer your question with a few questions of my own:

1. How many people make up your TOTAL friend list including Facebook, Twitter, Flickr, etc?
2. How many new people do you meet and “friend” each week on one of these sites?
3. As your dating, work or scholastic situation changes, how do your peer groups and relationship priorities change?

By answering these questions you’ve likely realized that:

1. You’re connected to WAY MORE than 150 people
2. Each of them is generating all sorts of NSN (news-stream-noise:  prounounced “non-sense”)
3. For many of these people, their relevance to your life is low, and changes as your life circumstances change
4. You’ve missed important news from people you really care about, because it was buried in all the NSN

So you have your answer….the social web is exceeding our Dunbar capacity…overrunning the human brain with too much information.  So how do we adapt?? We could wait for evolution to expand our brains, but that might take awhile—there’s a guy here in Austin who will never get there…

Or we could all become rock-stars and hire secretaries, managers, coaches and handlers. Finally, we could develop tools that can (implicitly and explicitly) learn who’s important in our lives, and then use that knowledge to promote some information, and filter out all the rest. This is what Minggl is doing behind the scenes, and a future version of Minggl will begin to bring this functionality to life.

More reading on Dunbar can be found on Wikipedia.org.