Strategy. Innovation. Brand.

Dunbar’s number

How Many Friends Can You Have?

No point in making it bigger.

No point in making it bigger.

Three years ago, I wrote an article about Dunbar’s number and how it affects my business. To recap briefly, Robin Dunbar is a British anthropologist who studies primates and their social circles. He noted an interesting correlation – monkeys with small neocortexes (relative to the rest of the brain) also had small social circles. Monkeys with larger neocortexes had larger social circles. These findings became the basis of the social brain hypothesis – that our brains put an upper limit on our social relationships.

Dunbar plotted the correlation – it moved up and to the right on a two-dimensional chart – and projected it to larger primates known as humans. Dunbar’s data suggest that the “natural” upper limit for human social circles is around 150 people.

That correlates roughly with my consulting experience. Many of my clients are small software companies that call me when they reach approximately 150 employees. They’re experiencing growing pains and they need some help. I’m happy to oblige.

The data suggest that our brain capacity – and especially our ability to think abstractly – somehow limits the size of the social circles we can maintain. But what if there’s a simpler explanation? As we know, simpler explanations are usually better.

What if the cause is simply the time it takes to maintain relationships? It takes time and effort to maintain a relationship and keep it active. What if we could use advanced technologies to reduce the “time cost of servicing a relationship”? Would that allow us to expand our relationships and maintain larger social networks?

Professor Dunbar hypothesized that social media could reduce the time cost of managing and maintaining relationships. Thus, it’s possible that people who are active on social media could maintain larger networks than people who maintain only traditional, offline, face-to-face networks.

Dunbar also hypothesized that social media might influence the “distinctive series of hierarchically inclusive layers that have a natural scaling ratio of approximately 3.“ Previous research had shown that primates – both humans and monkeys – have concentric layers of relationships. For humans, the first and most intimate layer typically has five people in it. The next layer out typically has no more than 15 – or three times more than the first layer. Subsequent layers have 50 and 150 members. Each subsequent layer roughly triples the previous layer. (The innermost layer is often referred to as the support clique, the second layer as the sympathy group).

So, by reducing time costs, do social media: 1) increase the total number of relationships? and/or; 2) change the distribution or size of the relationship layers?

The short answers are: no and no. (The full research article is here.) Dunbar’s researchers took two large samples of British adults (using different sampling methods) and found that:

  • The average social group size hovered around 150 – as predicted by the social brain hypothesis.
  • The two innermost layers – support clique and sympathy group – hovered around five and 15 members, as found in previous studies.
  • Heavy use of social network sites does not increase the total social group size. Nor does it appear to change the size of each layer.
  • Women have larger social networks than men (regardless of social media use), “…with females generally having larger networks at any given layer than males.” The differences are small but consistent.
  • Younger people have larger total networks than older people but the two innermost layers are approximately the same regardless of age.

What’s it all mean? We humans have “natural” limits to relationship networks that are largely consistent across gender and age groups and impervious to timesaving technical advances (at least in Britain). For me, this suggests that there’s no point in trying to grow our total network. It’s more important to invest in our innermost layers to enrich them and ensure that they don’t decay over time.

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