How many friends can a human have? This was the question a British anthropologist named Robin Dunbar proposed to study in the 1990s. His research, based on studying the human brain and observing different societies, concluded that the average group size where people know each other well is 150, now known as Dunbar’s number.
He hypothesized that humans could only comfortably maintain 150 stable relationships due to the limitations of our brain’s neocortex, the part responsible for conscious thought and language. This idea was further supported by observations of social group sizes in various societies—from hunter-gatherer communities to modern office environments. In each case, the average group size rarely exceeded 150, reinforcing Dunbar’s theory about the limits of our social capacity.
Dunbar arrived at this number by examining the relationship between primate brain sizes and their social group sizes. He observed that species with larger neocortexes tended to form larger social groups. Applying this insight to humans, Dunbar calculated the likely size of a stable social group based on the human neocortex, estimating the number at around 150. This was further corroborated by looking at human societies, where groups such as tribes and military units often naturally fell around this size.
The concept of the Dunbar Number has its critics and limitations. Some argue that the advent of digital communication technologies might expand or alter our natural group sizes. Others believe that different individuals might have varying capacities for social connections based on personality or other factors. While the number may vary for each person, it reminds us that we can only maintain a limited number of meaningful relationships and should prioritize the important ones.
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