Dunbar Number Matters: The Limit of Meaningful Relationships

In our daily lives, we interact with many people, meet new individuals, or sever our connections. We may like some, dislike others, and outright hate some. However, there is one question we rarely consider while engaging in these actions: How many people are there? How many people can I consider my friends? How many people do I know but don’t like? What is the maximum number of people I can truly know? There is a magical number that answers all of these questions: the Dunbar number.

A Brief Overview of the Dunbar Number

The Dunbar number can be described as the number of individuals with whom a person can maintain stable and meaningful social relationships. It is also considered the upper limit of people within a group that an individual can successfully and effectively coordinate with. When this number is exceeded, relationships weaken, the sense of belonging diminishes, and coordination becomes more difficult. For this reason, some communities, which I will soon provide examples of, have structured themselves by considering this number.

The Origin of the Dunbar Number

The number is named after the British anthropologist Robin Dunbar, who first introduced the concept. Dunbar discovered a correlation between brain size and group size in his research. This study was conducted on primates, which appeared to form groups and sustain their lives according to this number. The hypothesis he proposed was related to a part of the brain called the neocortex. The neocortex, as we know today, is the center of thought and is responsible for several key functions. It is also believed to regulate social relationships.

According to Dunbar, the larger the neocortex, the more social relationships one could maintain. Dunbar and his colleagues later applied this principle to humans and historical human communities. Their findings suggested that the average number should be around 150. When this number is maintained, members of a group can sustain their interactions. However, exceeding this limit often disintegrates the group.

One explanation for this phenomenon is that our hunter-gatherer ancestors formed communities of this size in the past. Similarly, many organizations, communities, and groups—both historical and contemporary—have been shaped according to this number: office teams, military units, communes, 11th-century English villages, and autonomous communities like the Amish.

What Should We Infer From This Number?

Although we have discussed the Dunbar number extensively above, this does not mean you cannot maintain relationships with more than 150 people. The number is merely an average, and Dunbar’s hypothesis is not an immutable law. Even today, some scientists conduct experiments to verify its validity. The number is also somewhat personal. While some individuals are socially active, others are more introverted. Socially active people might sustain relationships with 200 individuals, while more reserved people may limit themselves to around 100. Nonetheless, the Dunbar number represents a cognitive limit for all of us. No human can realistically manage relationships with 1,000 people. It might be 100, 120, 160, or even 180, but not an extreme number like 1,000 or 2,000.

So, what exactly does the number 150 represent? It refers to a total group size which one can maintain meaningful and stable relationships with. Dunbar further subdivides this group of 150 into tiers.

For example:

• 5 individuals: This is your inner circle, the people with whom you share the closest bonds. These might include your immediate family, romantic partner, and best friends. You might share everything with them, and, if needed, you would sacrifice for them.
• 15 individuals: These are your close friends, individuals with whom you have a strong bond but not as intimate as with the first tier.
• 50 individuals: This group comprises your general circle of friends.
• 150 individuals: As stated earlier, this is the maximum number of meaningful and healthy relationships you can maintain. These are not quite “friends” in the traditional sense but are more than mere acquaintances. For instance, your colleagues at work fall into this category—they are not close friends, but you regularly interact with them.
• 500 individuals: These are your acquaintances, people you know but do not interact with regularly.
• 1,500 individuals: This is the upper limit of the number of people you can recognize and remember.

These numbers may vary slightly from person to person. If you look closely, all these numbers are multiples of five. While Dunbar is not certain why this is the case, he suggests that it might be a fundamental trend observed in primates.

Conclusion

Although the Dunbar number has been applied in many contexts throughout history, there are studies that challenge its universality. For certain groups in the United States, this number has been reported to be around 290. Similarly, some individuals significantly deviate from the average value. For the general population, however, the number of people they interact with tends to fall within a predictable range. Some individuals may enter this group, while others may leave over time.

In this article, I aimed to shed light on a topic that is not widely known. For further information, you can refer to the bibliography or explore Wikipedia.

References

• Ekici, Ö. K. (2020, November 13). İnsan beyninin yapısı nasıldır? Bilim Genc. https://bilimgenc.tubitak.gov.tr/makale/insan-beyninin-yapisi-nasildir
• Ekleyen, Ç. M. B. (n.d.). Dunbar sayısı – evrim ağacı. Evrim Ağacı. https://evrimagaci.org/dunbar-sayisi-6799
• Lindenfors, P., Wartel, A., & Lind, J. (2021). ‘Dunbar’s number’ deconstructed. Biology Letters, 17(5). https://doi.org/10.1098/rsbl.2021.0158
• Dunbar’s number: Why we can only maintain 150 relationships. (2022, February 24). https://www.bbc.com/future/article/20191001-dunbars-number-why-we-can-only-maintain-150-relationships

https://en.wikipedia.org/wiki/Dunbar%27s_number