#85 - Dunbar Number and Networking

How Many Friends You Can Have?

Robin Dunbar, a British anthropologist and evolutionary psychologist, estimated that the maximum number of stable social relationships a human can maintain is around 150. He based this estimate on a mathematical analysis of the correlation between the size of the neocortex (the most recently evolved part of the brain) and the size of social groups in primates. This number has become something of a symbolic reference in discussions about cognitive limits in maintaining stable social relationships, although it should be treated as an approximation, pointing to serious limitations of our species in building relationships within groups significantly larger than this. The stability and cohesion of these relatively small groups depend on extensive personal knowledge based on face-to-face interaction. Direct interactions require time, and that is precisely what limits the size of a natural community.

150: A Constant Across Time

Interestingly, the group size calculated based on the size of a specific part of the brain is a number that appears remarkably frequently across a wide variety of human groupings, from prehistoric times to the present day. For example, the basic tactical unit in most of the world’s armies does not exceed two hundred soldiers — from the Roman century of about one hundred men to the modern company ranging between one hundred and two hundred soldiers, the size of such a unit has remained surprisingly stable, regardless of technology or methods of warfare. A number of independent studies in different environments have confirmed a human tendency to organize into relatively small groups, very close in size to Dunbar’s number.

But that doesn’t mean all 150 people are your close friends.

Who’s Really in Your Inner Circle?

Not all of the people in this innate group are your friends, but you can not built friendships outside this group. Some other sociometric studies suggest that we are only able to maintain very intense relationships with 10-12 other individuals at a time, which is about 10% of a social group we are part of. This group typically includes close family and a few trusted friends—roughly 10% of the full social group. The feels right to me - Most people can name their go-to circle pretty quickly.

A cultural footnote - Polish users forced Facebook to refer to connections as 'acquaintances' rather than 'friends', and it seems that Polish sceptical nature had very scientific foundation for this particular request

How Many People You Can Count On

While our brains limit the number of close, personal relationships we can maintain, humans have figured out how to cooperate in massive numbers—millions, even billions. This ability to organize beyond our cognitive limits is key to the resilience of large organizations and societies, which are capable of cooperation when it counts – like in the case of natural disaster or crisis.

To overcome our cognitive limitations, we build networks that are loosely connected but functionally powerful. These wider circles don’t require intimate familiarity, but they still matter deeply when it comes to communication, collaboration, and mutual support.

Once again army comes as a good illustration of that development. Soldiers in a company form tight bonds, but they integrate with other units through various coordination mechanisms – strong values and purpose and strict standards of operational routines, qualifications and outcomes. Using those different mechanisms we can scale the collaborative networks almost endlessly - the largest nations of our time – India and China – have each surpassed 1.4 billion members while maintaining the ability to function and achieve the goals of such a gigantic community. Walmart, the largest company in the world, employed around 2.1 million people in 2023.

Networking Beyond the Dunbar Limit

So yes - we've surpassed the Dunbar number in terms of collective functioning. We did not however figure out how to cross the limitations of our brains as individuals and therefore big networks of friends at social media accounts are illusionary and require caution. That doesn’t make large networks meaningless. Quite the opposite: loose connections can be incredibly valuable for spreading ideas, solving problems, and responding to crises—as long as we maintain realistic expectations. These connections aren’t substitutes for close friendships, but extensions of our social reach.

Stable relationships still matter most. But through those stable ties, we can link to others we don’t know personally—building resilient, layered networks that support individuals and strengthen communities.

The Essence of Modern Networking

Our brains may still live in villages, but our societies function like cities. We’ve evolved tools—cultural, technological, institutional—that let us scale trust beyond the tribe.

While you might truly count on only a dozen close relationships, you can collaborate effectively with many more if you build networks thoughtfully, manage expectations, and communicate clearly. Real friendship is rare and precious—but wider connections, if cultivated wisely, greatly amplify our collective strength and resilience.

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Resources and Notes

Dunbar, R. I. (1993). Coevolution of neocortical size, group size and language in humans. (Tom 16(4)). Behavioral and brain sciences.