Lately I’ve been reading a lot about “Dunbar’s number,” which is based on research by British anthropologist Robin Dunbar who claims that the optimal size of communities, and even business organizations, is approximately 150 members. If you push the boundary on that, relationships among group members tend to break down.
This is why, for instance, manufacturer W.L. Gore—famous for its non-hierarchical, team-based management structure—builds a new branch every time one branch exceeds 150. Within this limit each member has the cognitive capacity—specifically the brain size—to process the complex data necessary to maintain stable relationships with everyone else.
More interesting to me, however, are the smaller numbers that Dunbar assigns to more intimate groups: three to five for our closest friends and 12 to 15 for the next level of intimacy. Coincidentally, many work groups and committees I’ve coached are approximately 12 to 15, and they often divide up into sub-teams of three to five in order to tackle short-term tasks.
But wait (don’t touch that dial)—there’s more! The same numbers seem to hold up for rock bands. The majority of bands are 3 to 5 members (with the occasional 6- or 7-person group) while the extended team—including sound engineer, roadies, business manager, booking agent, etc.—often stretches to about a dozen.
Dunbar has plenty of critics who reject his “reductionism” (and I have some skepticism myself) but his numbers are fun to noodle on. And it gives me an excuse to not keep up with all my Friends on Facebook: I just don't have the brain size.
For further reading on Dunbar's number, look here.