The limits of friendship.

Nowadays, much of our lifestyle experience plays out on the Internet. People represent themselves on-line, often by a profile, along with their social links. Many revel in the number of connections they have. More is always better, or so it seems.

To infinity, and beyond.

There are hundreds of social-networking sites that facilitate the building of social relations with other people who share similar personal or career interests, activities, backgrounds or real-life connections. Popular sites such as Facebook, Google+, Twitter, and Instagram have made it much easier to cultivate and maintain friends. Some bushy-tailed NeXters have thousands of connections. But how many of them are truly meaningful?

So much monkey business.

In the 1990s, anthropologist Robin Dunbar was trying to solve the problem of why primates devote so much time and effort to grooming. What he discovered was the larger the primate brain size, the larger the average size of the social group. For example, the Tamarin monkey, with a small brain, has an average social group size of about five members. A Macaque, with a much larger brain, has an average group size of about forty members. He concluded that brain size helps them deal with the complex network of relationships they rely on to thrive.

How many people can you care about?

Using the average human brain size and extrapolating from the results of primates, Dunbar proposed that the number of people with whom the average person can maintain stable social relationships—relationships in which an individual knows who each person is and how each person relates to every other person—is limited to 150 (give or take).* Known as “Dunbar’s number,” this includes casual friends, close friends, and family members.

As it turns out, the Dunbar number roughly follows a “rule of three.” Of the 150 individuals in our core group, about fifty are friends. We see them often, but not so much that we consider them true intimates. Next is our circle of fifteen: our sympathy group, these are friends with whom we can comfortably confide in about most matters. The most intimate number, five, is our close support group. These are our best friends (and often family members), the people we can rely on in a crisis.

Too many friends, not enough meaningful connections.

One of the principal benefits of social media is it allows us to overcome our cognitive limitations to build larger and larger communities. Recent research (R. I. M. Dunbar – 2016) and (Bruno Gonçalves – 2011) suggests that the size of online social networks, such as the number of Facebook friends and Twitter followers, is similar to that of offline face-to-face networks. What that means is although social networks are changing the nature of human interaction, the Dunbar number seems to have remained remarkably constant.

What’s the take-away? Although we may widen our network to two, three, or four hundred people that we see as friends, not just acquaintances, keeping up an actual friendship requires time and effort. What keeps friendships strong is shared experience, and the more friends you have, the less you can devote to each one.

Dunbar’s number reminds us that once our core group exceeds 150, we lose the ties that bind. Beyond that, additional connections are merely one-dimensional droids or bait for marketers. So, NeXters, stop monkeying around—hug your family, treasure your close friends, and throw a party for the rest. Don’t forget to invite me!

* In practice, Dunbar’s number ranges from 100 at the low end (for wallflowers) and two hundred at the high end (for social butterflies). Human beings aside, scientists tells us no species has a more complex society than that of elephants. Pachyderm clans are seen as having a Dunbar Number range comparable to humans (100 to 200). An elephant never forgets—how about you?