Your Brain’s Twitter Limit: 150 Real Friends


Your brain's Twitter limit

Twitter’s approach to easy social connections lets people build big networks, often quickly. Celebrities attract millions of followers. Even non-celebrities can develop many thousands of friends; some resort to automation tools to build their following more rapidly. But what do all these connections mean? Clearly, one can’t interact with all these people on a regular basis. New research shows that there’s an upper limit to how many truly interactive social contacts we can handle.

Long before Internet-based social networks existed, British anthropologist Robin Dunbar proposed that the size of our brain’s neocortex limited the number of stable social relationships a human can handle. He estimated that it was between 100 and 230, with 150 being the most commonly used single value. This has become known as “Dunbar’s Number.”

Scientists at Indiana University decided to put Dunbar’s Number to the test by analyzing the Twitter activity of 1.7 million individuals. The team, led by Bruno Goncalves, found that Twitter users’ relationships topped out in the exact range predicted by Dunbar: 100 to 200 maximum. (Full paper: Validation of Dunbar’s number in Twitter conversations.)

While new users begin with few active friends, as identified by frequent and regular exchanges, the number of these relationships grow over time. Then, even for the most active users, their social bandwidth maxes out – they hit the proverbial wall, and simply can’t keep building active relationships.

The correlation of social network friend limits to Dunbar’s prediction for in-person relationships certainly suggests that he was on the right track in suggesting that there is a neurological constraint at work.

So, don’t be impressed by people with many thousands of Twitter friends; chances are, their REAL friend count is well below Dunbar’s limit. (I include my own Twitter numbers in that caution!)

  1. Tim Bete says

    Many Twitter accounts are used for 2-way communication but many others are a 1-way communication channel. Celebrities with millions of followers don’t have millions of friends, they have millions of people watching them. When I had a Twitter account for my book, GUIDE TO PIRATE PARENTING, I had about 9500 followers. They weren’t friends, they were people who enjoyed my humor. I tweeted back and forth with many but had no idea who most of my followers were.

    1. Roger Dooley says

      Quite true, Tim. Another class of friend is the “casual interaction” – once in a while, one says something, the other comments, and a short exchange ensues. But, they may not converse again for weeks. Or ever.


  2. Amy C. Teeple says

    I think savvy Twitter users create lists. This allows them to segment the people they are following and which conversations they really want to be a part of.

    I know there are some people who I follow with whom my conversations are limited (or non-existent) and others with whom I constantly interact. Makes sense when you put it in perspective of the Dunbar number.

  3. Mike Fraietta says

    The term “friend” has been hijacked by social networks and has given it a new, second common meaning. The only similarity is that they deal with human relationships. These two meanings aren’t meant to be confused.

    While I respect Dunbar’s theory, I believe it is becoming extremely simple in today’s complex, multi-network society. The connotation of the phrase “stable relationship” is changing rapidly. With different networks you can hold levels of tiers of stable relationships. One example; connecting with ANY twitter follower in front of an audience shows humanization and keeps other twitter followers content with their relationship to you even though you didn’t interact directly with them. Open dialogue and transparency allows for these multitude of stability tiers that were not realistically obtainable before today’s technology.

    Thanks for posting, Roger!

  4. Jason V says

    The classic (and hilarious) version of this is explained over at

    Writer David Wong’s term for this 150-person limit is the Monkeysphere, and he uses a number of funny points to illustrate the concept. Note: the article contains some NSFW language.

  5. Amir Homayoun Rafizadeh says

    Great post, and actually very valid. Thank god someone else is finally talking about this too. I would say the same argument would be very true on any platform (Facebook and LinkedIn). Specially on LinkedIn, since I hear lot of people with over 9000 connections pretending to know all of them (which we know is not true).

  6. Brain Supplements says

    People pretending to know over 9000 other people? Quite funny indeed 😉
    Thanks for this post, definitely puts social network sites in a new perspective for me!

  7. Brian Meeks says

    I really enjoyed the post. I constantly rail about the ridiculous obsession with follower count. In general, I block well over 50% of the people who try to follow me.

    I too am interested in people who are engaging on Twitter. I have found that a person who follows me, if they have a Listed:Follower ratio of greater than 5%, then they are one who isn’t trying to game the system. This is the value of blocking followers who are spammers and bots, it keeps the denominator honest and thus gets one a solid ratio.

    Really great post and comments. 🙂

  8. Naomi Niles says

    Ha, this is true. I talk to quite a few people every day one way or another. But, I know for sure people that I frequently communicate with are less than 150, especially on twitter.

    Honestly, it’s overwhelming and confusing. Lists aren’t enough. Who goes into what group? What are the expectations of the relationship with this person? Is it appropriate to write a semi-gushy intro (not that I know anything about that, lol)? 🙂

  9. Chris Herbert says

    I think using Dunbar’s number is a cop out to be honest. One assumes that you are using Twitter to create 150 to 200 friends. Individuals are using Twitter and other social networks for various reasons. I’m currently doing some research that challenges using Dunbar as the reason not to social network. I’m not suggesting that this is the purpose of your article but I am suggesting that there needs to be a way to leverage your followers.

    For example, when you meet someone and you have some things in common. You agree to keep in touch but life gets busy and you forget about your first encounter with that person. Have you lost an opportunity to make a new friend, a better friend, and new customer? What mechanisms do you use to improve your chances of re-connecting with that person to develop the relationship…or to remind you of the initial connection you made?

    That’s the role social networks can play. I don’t have the answer ..yet….but this is something I’m looking at figuring out.

    Thanks for writing about this. It’s a great background source for my research on developing personal/professional networks.

  10. Scott Morath says

    This is similar to Pareto’s 80/20 rule: 80% of your productivity comes from 20% of your effort. When you apply that to social media and B2B it really underscores the need to identify those few brand champions and nurture those relationships.

  11. Heroic Imagination (@HIPorg) says

    Glad to finally find a discussion on the web on this topic and hope we can get some help here. We want to LIMIT the amount of people who can follow us to a certain number AND create a waiting list of new followers who can be plugged in if some of our followers unfollow us or we decide to drop them. Any suggestions? With that said, how can we drop followers other than block them?

    1. Roger Dooley says

      HI, other than making your updates private and only approving those followers you want, there’s not a good solution. You could block people, I suppose, but that seems kind of negative. One way to look at it is that there’s not a big reason to limit followers, as having more followers doesn’t impact your experience much. Who YOU follow determines your timeline and who DMs you, which are a lot more important.

      Groups and lists are one way to alter your reading experience without capping your total numbers. I guess it all depends on your purpose in using Twitter – is it to keep in touch with friends, build your business, stay up to date in your field, or some other reason?


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