Curiosities Social

Dunbar’s number or how many friends we can have.

numero Dunbar

Aristotle said that “The friend of all is no friend of anybody” and he was right. According to research by Robin Dunbar, a professor of evolutionary anthropology at the University of Oxford, he established at 150 the limit of stable relations that a human being can maintain. It is known as the Dunbar number.

Dunbar, an anthropologist, psychologist and British evolutionary biologist and born in 1947, applied his social studies in nonhuman primates to humans. Dunbar’s (1993) hypothesis was that there was a relationship between the size of the cerebral neocortex and the number of social relationships that could be established. That is, in theory, the greater our neocortex, the greater the capacity we would have to process information involving a direct relationship. It is understood as stable social relationship that generates a cohesive human community and with an identifiable bond of union, that generate some confidence and investment of mutual time. Specifically, Dunbar’s number is 147.8 (rounded to 150).

Well, it seems that the number of Dunbar works and has worked in all communities. This anthropologist found that the communities of Neolithic hunter-gatherer tribes, the Bushmen, or American tribes divided as soon as they reached a famous number 150. Today this phenomenon continues to occur, as for example in military units.

número amigos dunbar

Having more Facebook friends does not mean being more social.

Social networking on the Internet does not escape the Dunbar number either. We live in a society where it seems that your social status is given by the number of friends you have on Facebook, Twitter or Instagram. However, Dunbar’s studies revealed that people with 1,500 friends had no social traffic differences compared to 150 friends. People with many friends have a real interaction circle with no more than 150 people, so expanding our network of “friends-acquaintances” will not expand our social circle beyond Dunbar’s number.

>> Related article: Facebook can depress you, according to science.

It’s one thing to add yourself as a follower or to like your last selfie, or even congratulate your birthday (remember that it’s Facebook that notifies you, not your brains) that you call or write to ask yourself how you are or tell you the last chapter Of your favorite series. To create a relationship you need to interact and have direct personal contact. There appear to be smaller-scale communities within today’s complex societies (Acedo and Gomila, 2016).

With this information, I ask you two things:

  • Would you be able to tell me the name and surname of 150 people you have on Facebook without looking?
  • Before Facebook existed, how many people congratulated you on your birthday?

A two-way process.

Our brain is programmed to handle information efficiently, so perhaps when we reach the limits of processing that information it eliminates irrelevant data, such as friendships that are no longer productive and end up coming out of our privileged 150 people who make up our environment Social interaction. It is a two-way process, both leaving and re-entering, provided there is cognitive space for them. We lose the friends of the school, then those of the university to those of the work, etc., there is no space for all. It is likely that as our cerebral neocortex increases we will be able to establish more interpersonal relationships, or not.

How much do you think you have your own Dunbar number?



Acedo-Carmona, C., Gomila A. (2016). A critical review of Dunbar’s social brain hypothesis. International Journal of Sociology, 74 (3). Doi:

Dunbar, R. (1993) Coevolution of neocortex size, group size and language in humans. Behavioral and Brain Sciences, 16 (4). Pp. 681-735.

Dunbar, R. I. M. (2009). The social brain hypothesis and its implications for social evolution. Annals of Human Biology, 36 (5), 562-572. Doi: 10.1080 / 03014460902960289

Larry, D. (2017). Is a Friendship Limited? An Inquiry into Dunbar’s Number. EXPLORE: The Journal of Science and Healing, 13 (1). January-February 2017. pp. 1-5.

Iván Pico

Director y creador de Psicólogo Colegiado G-5480 entre otras cosas. Diplomado en Ciencias Empresariales y Máster en Orientación Profesional. Máster en Psicología del Trabajo y Organizaciones. Posgrado en Psicología del Deporte entre otras cosas. Visita la sección "Sobre mí" para saber más. ¿Quieres una consulta personalizada? ¡Escríbeme!

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