Chimp Grooming and Dunbar’s Number
Chimpanzees congregate in groups called troupes and exhibit a behavior called grooming. Two chimps sit next to each other and one of them picks dirt and bugs out of the other one’s hair. This behavior helps build relationships between members of the troupe and it helps keep the high ranking males calm.
Humans are very closely related to chimps. The differences in our genetic make up is tiny. You would expect to see similar behavior in humans, and you do.
Humans congregate in groups called companies and exhibit a behavior called meetings. A small group of humans goes into a small room and show each other PowerPoint slides for an hour or so. This behavior helps build relationships between members of the company and it helps keep the high ranking members of the company calm.
The problem with both of these behaviors is that they don’t scale well as the size of the troupe/company increases. This is why chimpanzee troupes typically don’t exceed 40 or 50.
In the various primate species there is a correlation between this maximum troupe size and the volume of the neocortex .
In 1992, Robin Dunbar used this correlation to compute an estimate for the maximum troupe size in humans. This is known as Dunbar’s number, and it is roughly 150.
So that obviously means that the size of humans companies shouldn’t exceed roughly 150 members. Is that what we see in practice? Unfortunately, no. So what should we expect to see when company size exceeds Dunbar’s number? Basically we would expect to see the company break into subgroups just as chimp troupes do. And that is exactly what we do see. Whenever I’ve been at a company which grew past about 150 or 200 members, you would see members of different subgroups (e.g. development, marketing, sales) refer to each other as them, and actively compete with each other. A similar phenomena occurs when the company grows to the point where a single group (e.g. development) exceeds Dunbar’s number.
At least, that’s my experience. What have you seen in your field studies?