There’s a scientific theory that humans’ cognitive abilities are limited to pursuing and maintaining stable relationships with about 150 people. Furthermore, it claims that it’s the limit of the average person’s network size. Today, we call this theory Dunbar’s number. 

If you want to find out more, and how it relates to efficiency in your business, this article will go into further detail.

What is Dunbar’s Number?  

Dunbar’s number is a concept proposed by the British anthropologist Robert Dunbar in the 1990s.

He found that the cognitive capacity an individual can track and maintain stable social relationships with is capped at 150 people. If the groups exceed that limit, they’re more likely to split or collapse. This applies to individuals you share synchronous experiences with, so Facebook friends or followers don’t apply here. 

The lack of touch and face-to-face time leads to more superficial relationships. The result is a wide range of people who you lack deeper connections with. Consequently, interacting with too many individuals results in a lower capacity for meaningful relationships. 

Why did Dunbar Settle on this Number?

Dunbar established the number 150 by using neuroimaging and observing the time primates spent on important social behaviours, such as grooming. To arrive there, he inferred the regression line of the relationship between group size and relative neocortex size in primates and compared it to that of humans.

The neocortex is a structure in the brain responsible for perception, decision-making, language, emotions, etc. This is where the higher cognitive functioning of the brain originates from. Dunbar attributes the complexity of this structure to be in a quantitative relationship to the size of social groups in primates.

According to Dunbar, the limit of the relative processing capacity of this part of the brain structure limits group size.

Is There Further Proof Supporting His Theory?

Another theory, the “social brain hypothesis” explains the immense size of the primate brain compared to that of other vertebrates. This is linked to the management of their large and complex social groups as well.

In comparison, the size relationship between brain size and social group size is qualitative instead of quantitative in other mammals. Usually, brain size in animals is associated with categorical differences in mating systems, the largest being found in species with pair-bonded mating systems.

Further anthropological and historical records also support his theory. Dunbar found the average group size in modern hunter-gatherer societies to be about 150. The armies of the Roman Empire, Spain in the sixteenth century, and the Soviet Union also constructed their companies of up to 150 individuals. Further breakdown of those showed groups of fifty and ten or fifteen. 

Modern examples of something as mundane as Christmas-cards-sending activities showed a limit of 150 for most typical U.K. households.

Now, let’s find out how exactly Dunbar’s number is constructed.

What does 150 Stand for?

Though 150 is representative of the findings, Dunbar initially proposed a natural range of variation of 100 – 250. What is known as Dunbar’s number now is simply the most generally applicable and cited figure of his theory.

If the size were to extend up to 250 or be as low as 100, the structure of the group would have to change. 

A group below 100 can easily regulate their behaviour with informal, reciprocal exchanges. As soon as it goes beyond 150, however, the group requires authority.

Dunbar’s number also has other properties. It can be broken into several circles that have their own concepts. These circles, or layers, are always three times the size of the previous one. He generated this formula from interviews and analysis of experimental data.  

What are the Distributions for Each Circle?

The circles are representative of the emotional closeness to the individual; when it decreases, the number in the circle increases.

The smallest layer consists of only 1.5, called EGO. The second circle consists of five people and is for close relationships like loved ones. This is the most intimate group of friends and family.

The circle reserved for good friends consists of only 15. You turn to them for support and sympathy. Then comes the circle of friends, with 50 individuals as the limit. This circle consists of people who you’d consider close enough to invite to small dinner parties. 150 is the meaningful contacts circle. You would invite them to larger parties – though, for more social and extroverted individuals, this number is expandable to 200.

Going to less intimate relations is the 500-circle of acquaintances or those you might exchange pleasantries with. Expanding further, Dunbar noted that up to 1,500 are known names. What comes after are only categorised as known faces.

How can Dunbar’s Number Help Maintain your Business?

If you’re a scaling business founder, you have already encountered the many problems with a growing workforce.

Are you noticing a decrease in efficiency, especially interpersonally? Is communication becoming more difficult and conflict increasing? Does duplicate and redundant work happen regularly?

When you started out, and your business was still growing in numbers, communication was probably easier and the workflow faster. Your business didn’t require much structure, in comparison to one that is much larger and already has a well-established staff.

Those are common changes any scaling business goes through, what matters is only how you learn to deal with it. The problem gets worse if not addressed.

After all, many roles are dependent on relationship management, like sales, business development, recruiting, consulting, marketing, and so many more.

This is where Dunbar’s number helps. 

Team Interaction and Contact Management

As previously noted, a social group of 100 can easily converse cohesively. The work environment might even allow for informal exchanges. Behaviour regulates itself naturally for smaller groups.

Once your number of employees grows, according to Dunbar, the structure of the human brain can no longer keep up with the capacity. The more social complexity increases, the larger it grows. 

To deal with this we require contact management, as well as established rules and regulations, as observed for example in the world of online gaming. The groups formed their function as simple alliances created for specific task completion, only lasting as long as needed. 

Looking at these examples gives insights into ideal team interaction in offices. 

Like in gaming communities, too large of a group increases the risk of infighting due to a lack of leadership. Smaller, semi-independent units are more successful in task completion. 

In smaller numbers, individuals get a higher sense of purpose that helps build community and increase efficiency. 

How to Incorporate Dunbar’s Number into your Business Structure

To start, limit the separate groups of your company to below 150. This is the maximum number of people your employees should deal with regularly. Doing this helps achieve great results in productivity and a better workflow for your employees.

If we go further, there are many ways in which to interpret Dunbar’s number.

For a group to remain stable in communication, it requires physical closeness. It would make sense to separate departments, with one representative that deals as a touchpoint whenever those interact, to avoid conflict.

This would mean that, at most, your employees should only work with up to 15 people regularly. Depending on your company’s structure, be it Bureaucratic or Flat, you or your representative in that department should be part of that circle.

Expanding the Concept with DAO

What is a DAO?

It isn’t necessary to have an authority-led work setting, as Dunbar’s number suggests. A DAO (Decentralised Autonomous Organisation), for example, is a community-led project. This structure requires no authoritative figure to control and manage every action made by the group. Instead, it’s fully autonomous and transparent. 

In a DAO, the group or community members collectively make decisions by drafting proposals and voting. Rules are established by contracts, where the framework of how the DAO operates is laid out. 

The word dao is Chinese. It stands for path and is used by Confucians to describe how humans should behave in society. This perfectly describes the work ethic this community structure follows. 

How to Connect the Two Concepts

If you want to incorporate this community collaboration project into your business structure, follow Dunbar’s suggested numbers.

With each new level, transaction frequency should decrease, as the group increases in number. 

This is important because they represent different functional capabilities, since the social transaction is less intimate the larger the group grows. 

When individuals interact within small groups to solve problems, it helps decrease failure. Each individual spends more time on specific tasks assigned to their field of knowledge, making them more efficient. Results are no longer unnecessary duplicates of each other, and no time is wasted on undoing messes created by others.  

Doing so gives you insight into potentially redundant hires resulting from a sudden growth of work in your evolving business. 

The best way to determine this is by compiling as much data about the history of contact for each interaction with your employees. A task is achievable by distributing management for each group.


As previously noted, this is only one way of many to use Dunbar’s number metrics for the structure of your business. These layers only comprise the margins of each group’s size.

Freely adapt and decrease or increase the volume of each, as long as they represent the functional capabilities. 

In short, the outcome of using Dunbar’s number is stable communication with a greater number of people across a wider variety of interaction points. The problems of lacking motivation, poor hiring, and inconsistent management are thereby easily eliminated.

About the author

EWOR is a school conceived by Europe’s top professors, entrepreneurs, and industry leaders. We educate and mentor young innovators to launch successful businesses.

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