About 20 years ago the evolutionary anthropologist Robin Dunbar proposed his eponymous number:
Dunbar’s number is a theoretical cognitive limit to the number of people with whom one can maintain stable social relationships. These are relationships in which an individual knows who each person is, and how each person relates to every other person. Proponents assert that numbers larger than this generally require more restrictive rules, laws, and enforced norms to maintain a stable, cohesive group. No precise value has been proposed for Dunbar’s number. It lies between 100 and 230, but a commonly used value is 150
Dunbar’s number was first proposed by British anthropologist Robin Dunbar, who theorized that “this limit is a direct function of relative neocortex size, and that this in turn 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.” On the periphery, the number also includes past colleagues such as high school friends with whom a person would want to reacquaint themselves if they met again
This preliminary research served as one of the major points of discussion in Robin Dunbar’s Grooming, Gossip and the Evolution of Language. At least the descriptive model of the rough value of the number seems to have embedded itself into the Zeitgeist. To capitalize on his ideas in the web 2.0 world Robin Dunbar has come out with a new book, How Many Friends Does One Person Need?: Dunbar’s Number and Other Evolutionary Quirks. I recently heard him discuss on the radio the phenomenon of people with thousands of Facebook “friends.” Of course these aren’t really friends. People use Facebook for different reasons. Many people use Facebook like a business card, or a way to communicate with their fans or followers. In other words, more like twitter. The majority probably use Facebook the way it was intended, to mimic your real life social graph, and perhaps expand it on the margins.
After a few discussions with people who use Facebook and have given some serious thought to how these social technologies can extend our abilities, three assertions were made which I found intriguing. Below I have reformulated and elaborated upon them (that is, I added my own spin):
1) The number fixates upon a modal/median number of relationships. There is a “long tail” of individuals who have many more meaningful relationships, and this is important to overall network structure.
2) Technology can potentially double Dunbar’s number. In other words, instead of having ~150 meaningful reciprocal relationships you can now have ~300. Presumably because social technology extends our capabilities and introduces efficiencies by removing some of the “dead weight” overhang.
3) Dunbar’s number applies to coherent and self-contained groups. A pre-modern tribe or a Hutterite colony. It is not appropriate for the more multivalent and fluid relationships common in the contemporary word. For example, the same individual may be members of dozens of urban “tribes” with 10-30 members (though the coherency of the tribe may be highly subjective).
What are your thoughts? I ordered them in order of my own personal assessment of the plausibility of the assertion, but inverse order of the importance if the assertion is born out. I think #3 is a revolutionary possibility, a qualitative change of kind. In contrast, #2 is more evolutionary, a quantitative change of degree. #1 is correct to some extent, though the idea of “connectors” with which serve as nexus points within a network has been mooted elsewhere.