In detail

Dunbar's number: how many friends can we have

Dunbar's number: how many friends can we have

Most people could say they count their friends with the fingers of one hand. And, indeed, they are not so far from reality. And you, are you who prefer good friends but more intimate or quite the opposite?


  • 1 Who was Robin Dunbar and why is his theory so famous?
  • 2 The evolution of Homo Sapiens and social relations
  • 3 Dunbar's number in modern times and social networks

Who was Robin Dunbar and why is his theory so famous?

Robin dunbar, an anthropologist at the University of Oxford developed his Social Brain Theory. In it, certain limits are established regarding the number of friends that each person can have.

These friends are classified and distributed according to certain categories from least to highest ratio. According to Dunbar, you can't have more than 150 friends, but at different levels of relationship and commitment, so to speak.

In this way, an average person has only one or two best friends. The classification continues with about 5 close friends, 15 good friends, 50 close friends and about 100 friends without more, that touch the line of what we understand by acquaintances.

Obviously each relationship involves wear. Thus, the time we dedicate as well as the effort with which we try to cultivate a certain relationship will not be the same with our best friends than with other friends or acquaintances.

The closer and closer the relationship, it will have a better quality and we will develop ties with greater intensity. It is no longer simply that we do not have time to maintain so many social relationships, is that we must focus on each other Not to saturate our brain.

The evolution of Homo Sapiens and social relations

In the end, this explanation goes back to the evolutionary process of our species, due to the increase in size of our brain. Since, the larger the neocortex, the greater the number of individuals within a social community.

And not only increases the number of social relationships, but the sophistication and complexity of each of them. The result is more varied and complex interactions, such as laughing or sharing various hobbies.

If we compare the skull size of the primates, we will see that it is significantly smaller than that of the human species today. And, in addition to having much narrower and more limited social circles, the social activities they carry out are not as elaborate.

While primates interact with other members of their community or even with other species such as ours, their social activities focus on simpler acts like touching or grooming.

Anthropologists and biologists agree on one aspect: to survive change and the environment, it is essential to be able to relate properly and be part of a community. It is not enough just to feed and cover the basic physiological needs.

Establish contact, adhesions and alliances with individuals of the same species, as well as establishing social relationships in which we feel part of a group and supported by the rest of the members, is not unique to Homo Sapiens Sapiens, but from our ancestors and other species.

And the truth is that in one way or another and depending on the environment or context in which we find ourselves, human beings will establish links whenever they can and the intensity of these will be determined by the total number of friendship relationships they have in total .

Dunbar's number in modern times and social networks

If you have tried your luck and have gone to live abroad or to another place unknown to you, either because you have obtained a scholarship, to look for work or for personal reasons, you will already know what it means to try to establish relationships outside your comfort zone .

Although some feeling of fear and anxiety invades you before the change and the lack of friendships to count on at that moment, in the end you try to make the effort to meet people. After all, we human beings are social and one of our needs is to socialize.

Going out to find friends in person is not an easy task. But even so, we know that it will bring us great benefits and that is why we try. Now look for sayings friends on-line and through social networks it's something very different.

Starting from the fact that the term "friends" used by some social network is nothing more than a distortion of what a true friendship implies. Social networks will help you to meet up with former friends or acquaintances or to maintain contact.

But they will hardly help you to cultivate close and quality relationships, because at the end of the day, it does not facilitate the necessary and intense enough contact as to cultivate these relationships and strengthen them over time.

So you know, try to keep your friends really, that circle closer than first by affinity and then by dedication you have maintained in time. We don't tell you, so does anthropology and science.


Barrett, Dunbar & Lycett. 2002 Human Evolutionary Psychology. London: Palgrave ISBN 0-691-09621-X

Dunbar 2010 How Many Friends Does One Person Need? Dunbar's Number and Other Evolutionary Quirks. Harvard University Press, ISBN 978-0674057166