(Not) Done with Dunbar’s Number


Flickr Photo by Charles Haynes

Yet again, Dunbar’s Number is popping up. Professor Robin Dunbar first stated in the 90s that the maximum number of relationships our tiny human brains can handle is 150.

A Sunday article in the Times of London has brought this up anew, thanks to the good Professor himself. The context, specifically, is social networks, and the articles popping up seem to warn us that having, say, 800 Facebook friends will melt your brain (yes, I exaggerate- maybe).

People who jump on this bandwagon, I say, are missing the point of how social networks work. Anyone who thinks I can talk to 1,000 people meaningfully all the time is insane (and certainly thinks I am). It’s the groups within groups- my “baby Dunbars”- that make scaling possible. Yes, that’s cheating, but I am getting around to further explanation soon.

You know what I can’t handle? The number of times Dunbar’s number keeps coming up in terms of social networks. That’s what makes my brain explode. I will be writing more on this.

What are your thoughts on the subject?


  1. Some of the debate, I think, boils down to semantics. What do we mean by “relationships”? I have read the hypothesis behind Dunbar’s number to mean relationship on a somewhat intimate level–that you know and remember details about the person’s life on a more than merely casual level. Others appear to take a more liberal approach to the definition, and include ‘those with whom I interact,’ as the definition of a relationship. Taking the more strict definition I’ve laid out, it’s simply hard to keep everyone’s info straight.

    Ultimately, I think the core of the theory behind the number is probably solid, and that people drift in and out of the 150. That doesn’t mean I only interact and socialize with 150 people–to me, it means that 150 people are within that group who know me well enough both online and offline to remember details about my life–and I theirs.

    Looking forward to more on this!


  2. I agree that Dunbar’s number doesn’t match up with how many people you can follow on Twitter. But I do think it matches up approximately with how many people contribute significantly and repeatedly to your life. The real insight is that there is only so much time, emotional, and intellectual energy in a human being. Do you want to use yours to follow 10,000 people’s tweets and 2000 people’s FaceBooks, or use it to engage more deeply with 100-200 people? You can’t do it all. Where are you going to invest your time and attention?

  3. Interesting and creative piece, that picture was a little gross. My worst fear is I will that I will not understand Dunlars number. My theory born

    Its about upbringing someone like Chris Brogan says he moved around alot as a kid. (Stick with me) and has no trouble with all those Twitter followers but someone less travelled as teenager will have more trouble interacting. Technology will help you
    compensate but Dunbars law will win everytime if you grew up with less travelling socialising. Networking is learnt and can cultivated. That is the nature versus nurture argument aplied to Dunbar (who I have never heard of, some networker)

    Cheers from London Doug

  4. Dara, that’s an interesting theory regarding moving around a lot. I moved every three years as a kid (internationally). I’ve always made friends easily and readily adapted to my new communities, so I kind of get the connection. I have broad circles of friends from many different areas.

    However, I think it has more to do with the personality of the individual than any sort of adaptive socialization. My sister had the same upbringing, but a very different experience than I–she’s quiet, less outgoing, and has small circles of very close friends.

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