Dunbar's Number: How Many People Are in the Human Mind's Social Limit?

Each of us is surrounded by dozens, perhaps hundreds, of people: our family, friends, colleagues, former classmates, and social media connections. But let’s be honest: how many of them do we truly share a deep, meaningful bond with? It is precisely at this point that the Dunbar Number comes into play.

What Is the Dunbar Number?

The Dunbar Number is named after British anthropologist Robin Dunbar. Based on his research in the 1990s, he demonstrated that the human brain is capable of effectively managing a social group of approximately 150 individuals. In other words, our brains have a natural capacity to understand, track, and maintain relationships within a network of about 150 people.

This number does not refer merely to people we recognize by face; it includes those whose identities and roles in our lives we genuinely know. These are the people we invite to weddings, remember birthdays for, and reach out to in times of emergency.

An information card visual about the Dunbar Number. (Generated by Artificial Intelligence.)

What Is Its Biological Basis?

Dunbar arrived at this number by examining the relationship between brain size and group size in primates, then applying these findings to humans. The result was clear: the size of the neocortex—the part of the brain responsible for processing social information—limits the number of social relationships a person can sustain.

This suggests that during human evolution, our brains developed a specific capacity for social interaction. In a sense, this number can be thought of as our “mental social capacity.”

How Are Social Circles Layered?

The Dunbar Number does not end at 150. This social network is organized into distinct layers:

• 5 people: Our closest confidants, those who provide emotional support,
• 15 people: Close friends we see regularly,
• 50 people: People we trust and invite to social events,
• 150 people: The maximum number with whom we can maintain regular relationships,
• 500+ people: Individuals whose names we recognize but with whom we have no deep connection.

These layers can shift over time. When we grow closer to someone new, one or more individuals often fall out of this circle, because our brains cannot sustain an unlimited load of new social demands.

How Social Circles Are Layered. (Generated by Artificial Intelligence.)

Has Social Media Overcome the Dunbar Number?

You may have 800 friends on Facebook or 2,000 followers on Instagram—but how many of these people do you genuinely communicate with? According to Dunbar’s research, digital platforms do not expand the limits of our brains. Even though algorithms make us feel connected to many people, real social bonds remain constrained.

Liking a photo of someone’s wedding does not mean you understand any part of their life. True connection requires effort, time, and attention. The digital world offers us more connections, but these connections tend to be more superficial.

From Past to Present: How Have Societies Shaped Themselves?

The Dunbar Number does not only explain individual social circles; it also illuminates the historical structure of human communities. Most primitive tribes consisted of around 150 members. Medieval villages typically had populations near this number. Even today, many military units, corporate departments, village associations, and school classes are structured within this limit—because this number represents the maximum at which people can know each other and trust one another.

When we exceed this limit, we must rely on rules, hierarchies, protocols, and algorithms to manage people we do not personally know.

Just as on social media… Consider this: how many of the people whose birthdays you celebrate on Instagram do you actually meet in person? And when we simply comment “best wishes” on someone’s post and move on—is that a real relationship, or merely a digital gesture?

Although we may seem to “know” hundreds of people in the digital world, most of these connections remain weak and superficial. True closeness is built through hearing someone’s voice, asking about their well-being, and spending time together. But the Dunbar Number reminds us: you cannot do this with everyone. Mental energy is limited.

So What Should We Do?

The Dunbar Number may seem like a limit, but it is not a disadvantage. On the contrary, it offers us an opportunity to allocate more meaningful time to a smaller number of people. This number can guide us in reviewing our social circles, cultivating genuine bonds, and distancing ourselves from digital noise.

Think about it: how many people do you sincerely ask, “How are you?”