The Dunbar number

Numbers - woman countingThe more I use Facebook the more I’ve come to appreciate the conclusion of British anthropologist Robin Dunbar that there is a “cognitive limit to the number of people with whom one can maintain stable social relationships.” This has inspired me to reprise an earlier post, “Too big to groom.”

Much has been written about the optimal size for communities and business organizations. Primatologist Robin Dunbar says any group becomes inefficient when it exceeds approximately 150 members.

Coincidentally, many businesses—like W.L. Gore and Brazil’s Semco—have discovered on their own that when one of their organizations exceeds that size it loses its sense of community and needs to be split into smaller units. Dunbar has also found that three to five is the optimal number for intimate friends, which happens to fit the size of most rock bands and small business teams.

But until this week I had missed the evolutionary link behind Dunbar’s numbers. In his anthropological research he discovered that when communities of primates began to exceed 150, it weakened their social bonding based on their ability to groom each other’s fur!

Suddenly, things I've observed as a management consultant make sense. For instance, whenever I worked with mining and manufacturing sites that exceeded 150 workers I was always mystified by the fact that employees seemed totally uninterested in combing each other’s hair. Perhaps you’ve noticed this too.

This brings evolutionary meaning to terms like “grooming your successor.” But in too many large organizations people just aren’t getting groomed at all! No wonder there's been a global economic slump. We’re growing too big—and too grungy.

Hopefully, BLFR readers, you can now make it a priority in your organization to pick the nits out of your fellow employee’s hair and fur. Then you can watch your company’s productivity skyrocket!

Of course you’ll want to make sure this is consistent with your company’s human resource policies. (BLFR is not responsible for loss of employment from applying any heterodox ideas you learn here.)

For an earlier post on this topic, including Dunbar’s other numbers, check here.

View the archive »

Never miss a post… get 'em by email or rss »


  1. I've always found that after 150 people, it gets really and seriously expensive when you have to bring in cakes on your birthday.

    1. Gary, for non-misanthropes 50 close friends seems reasonable.

      But Facebook "friends" are a different animal altogether. When I'm told by FB that a friend has a birthday, I'm always asking, "Who IS this person?"

Leave a Reply

Your email address will not be published. Required fields are marked *

View the archive »

Never miss a post… get 'em by email or rss »