Psychologists prove that our brains can only cope with 150 friends

Have you have ever thought “I can’t be bothered to keep in touch with all these random people any more”, decided to have a “Facebook cull”, and proceeded to delete a vast majority of people from your list of friends? It’s something that many of us do without much thought, but there is in fact a scientific principle that explains why we do it.

Research in the 1990s by British anthropologist Robin Dunbar showed that 150 friendships appears to be the highest number that humans can want, can need, or can bear.

It’s an evolutionary thing. Social primates build communities to form bonds and protect one another. Yet a number limit must exist in a community, because groups that are too large compromise their sense of intimacy, their cohesion, and their chances of survival.

After studying many primate species, Dunbar realised that the size of a social group increases with brain size. He came to the conclusion that 150 is the limit when it comes to humans. It is certainly a figure that has recurred throughout history: Neolithic farming communities tended to split up if they exceeded 150 members; the Romans made 150 soldiers the basic unit of an army; the size of a nomadic tribe is around 150. And many subsequent studies have supported Dunbar’s simple finding that you can’t realistically maintain regular contact with more than about 150 people.

But modern online social networks (i.e. Twitter and Facebook) allow us to have lists of hundreds – or even thousands – of friends. So doesn’t that disprove Dunbar’s findings? It would seem not. Latest research from Bruno Goncalves at Indiana University reveals – even if we do have enormous lists of friends and followers – around 150 is still the maximum that our brains can truly withstand.

After studying social networks of three million Twitter users over the last four years – studying 380 million tweets in the process – Goncalves discovered a common habit amongst Twitter users. People start using the service, collect a huge number of friends, and then get overwhelmed. And, incredibly, this limit occurs … somewhere between 100 and 200 people.

Full story: IO9 Science


About MRW

Physics person.

Posted on June 1, 2011, in Psychology and tagged , , , , . Bookmark the permalink. 1 Comment.

  1. Terrific post however , I was wanting to know if you could write a litte more on this subject?
    I’d be ver thankful if you could elaborate a little bit further.

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