What’s the new Dunbar number?

Network Robin Dunbar is a British anthropologist and evolutionary biologist. In the early 1990s, he proposed that 150 was the maximum number of individuals with whom any of us can maintain a social relationship.

Personally, I think this number is high.  Only the most gregarious of my friends seem to have anything like this number.  For me, the number is closer to, say, 50. 

But I can’t help noticing that I now have many more than on Facebook. Well, it would be wrong to call all these people "friends," but some of them will I think become friends, and some friends with whom I have lost touch will reappear here.  One of them just signed on as a friend today.  (Thank you, John.)

Gregarious people, well, God knows how many people they can keep track of with the new media.  I mean, with cell phones, email, text message, networks on the internet, even a cave dweller with an attitude problem should be good for several hundred.   

Your thoughts and ethnographic notes please.  I figure LinkedIn and Facebook by themselves should expand my personal Dunbar number well past 150.  How about you?

13 thoughts on “What’s the new Dunbar number?

  1. Daria

    I guess that you can definitely have social relationship with 150 people, but spread in time – meaning some relationships being deactiviated while others are activated. There are also very differnt levels of having relationship. When we count our co-workers, neighbours, family and that nice lady in the local grocery store, we can easliy come up with 100 – 150 persons we have one or another form of relationship. I’ve also run across a number of 70 as the number of people our brain can handle to have the relationship with. We all need to have the relationships, we need to belong to groups, but of course our possibilities are limited and here come social media. What is fascinating about the social media is the fact that they work as our social live hard disc. There are place/s where we can storage virtually our contacts and activate them physically when needed.

  2. Renan Petersen-Wagner

    it’s interessant to postulate that we can have a maximun number of people to have a relationship. In Orkut (www.orkut.com), for example, the maximum number of friends that you can have is 1,000 (one thousand). I know a lot of people in orkut who has two, three, or even more profiles, so they could have more than 1,000 friends. But, for what reason? Are these friends really friends? Or, are these “friends” just people that you know, or, better, just people that knows you.
    I think that these are people that have went across your life in a, maybe specific, moment, and so, becomes your “friend”, or as we say here in Brazil, a meeter, someone that you have just met, and your friendship stops there. Someone that you have chatted in a party while drunk, and the day after you add on orkut, and becomes your friend.
    If we could see the day that a person added someone in orkut (or facebook), or the day that someone added this person, or when the person joined a community in a timeline, *maybe* we could start understanding who this person is, relating these life events in internet to life events as consumers (for example). The first step (for me), it’s to try to understand the meanings that these person attach to these communities, or friends [the have aspect], to in a final moment, understand who she (he) is, and what she (he) will do as a consumer [the do aspect] (these ideas comes basically from Sartre and Belk).

  3. Stephen Denny

    My Dunbar is currently out of control. If LinkedIn is today’s proxy for “relationships,” then I have over 250. I’ll readily admit that I’ve at least spoken to almost all of them and the majority are personal (ie, face to face at one point or another, and several who might actually be considered real friends) contacts, but the “loose links” seem to be heavier than Dunbar might have originally included. Don’t know if this is a good sign or a bad sign, or just a sign of the times.

  4. Peter

    If we add to our list of friends-in-the-physical-world all those people we feel ourselves to be good friends with in the world-of-TV-and-film-fiction (eg, CJ Cregg, Detective McNulty, Tony Soprano, Jason Bourne) — ie, “people” we care about, and whose “lives” we follow with interest — then we probably easily reach a number greater than 150.

    BTW — Professor Dunbar’s office is 5 minutes walk from where I write this.

  5. LK


    maybe take the 5 minute walk and ask Prof Dunbar how many contacts he has on linked in, facebook, etc?

    i have been playing around with friendster, my space, linked in, and facebook … so for about 4 years now. it was a game at first, then it became a performance (ie many seem intent on showing the rest of the world that they have 573 ‘friends’) but what i’ve found so often is that people that are barely friends or colleagues — barely in the sense that there’s not much of a foundation for a relationship — send out an e-invitation after a cursory interaction. So this definition of “friend” is very different from Dunbar’s 150. There’s a qualitative aspect in his number that may well still hold true.

  6. neilperkin

    Definition is everything in this game. I suspect that the degrees of social relationship between ‘friends’ on online networks varies wildly (as you intimate) but perhaps what they facilitate is more efficient management of all those ‘tier 2’ friends…people you know and like but who’ve not necessarily seen you drunk and making a fool of yourself…

  7. William Newman

    Wasn’t the Dunbar number originally the extrapolated natural band/tribe/pack/whatever size for humans? As I understood it, it was not so much the people you had casual knowledge of, even useful casual knowledge of. Instead, it was the number of people you could keep enough track of (following reputation and trust and mutual obligations and whatnot). And below that number, things could Just Work (without post-monkey technology like formal hierarchy and written rules and so forth). If I’m not mistaken about that understanding, then most of the anecdotal evidence here seems to be missing the point. Monkeys have useful casual knowledge of many, many things (fruit-bearing trees, water holes, paths). But keeping track of everything you need to know about another band member seems to be expensive enough that their bands stay much smaller than the number of food sources that they can remember. Until someone shows me otherwise, my guess is that Facebook-level power tools for the brain just make it more convenient to keep track of useful people in a way that is comparable to the way a nomad keeps track of useful oases and water holes, and don’t have much to do with the way a nomad keeps track of his second cousin in the third tent to the left.

    If you wanted to address what I understood to be the point of the Dunbar number, I think it would make more sense to use anecdotes from collaborations over the Internet. I run such a collaboration, a software development development project (“SBCL”). It currently has about twenty developers authorized to write to the central source code database, and runs basically without formal procedures. I have been pleased how well that has worked up to 20ish developers, but don’t think it would work past 150, with or without Facebook technology.

    I do rather expect that other forms of computer power tools for the brain will tend to let us bypass or outright replace various kinds of hierarchy in large groups. I think I can even see it happening already in some kinds of large groups (with citeseer and arxiv, for example, and arguably google too). But I’m not sure the particularly vague touchy-feely services like Facebook are the same kind of thing. They’re very important in their own way, but they seem pretty separate from the harder scaling cutoffs that I thought the Dunbar number was about. An infantry platoon is a very different organizational animal than an infantry battalion, and no one has figured out how to soften the difference very much. Scientific journal communication in a field with 5000 researchers used to be a very different thing than in a field with 50 researchers, and it looks to me as though we have figured out how to soften the difference a lot. Facebook and the like have had a huge impact in their way, but I’m still uncertain how it fits in. Among other things, note that Facebook doesn’t seem to be addressing a problem which was previously addressed by hierarchy and formal rules. Maybe with a few years of hindsight it’ll be easier for me to figure it out…

  8. lauren

    following on from what william was saying, if i was going to calculate all my friends on all my online social networks into the dunbar system, i think they would probably only count for 1, maybe 2. not ‘cos i’m a loser and only have that many friends, but the evoloutionary mental capacity that i’m using is only that i use myspace to access my friends – i don’t need to actually *remember* things about them, like names, birthday, what their favourite colour is, what their girlfriends name is, etc, as all that information is actually given and easily accessible outside of my memory. in fact, given that blurb (which is not based on anything except waffling) i would say that with online social networks, the dunbar numbers will start to go down. we’ll start to only retain the information about where to get information about our relationships from, not the actual information.
    does any of that make sense or am i way off?

  9. MAS

    I think we are capable of expanding our personal Dunbar number by our required circumstances. When I worked in finance, we had 100+ people in our section, and I knew them all, their families, etc. Add into that mix the 100+ that attend the church I go to whose homes I’ve been to and that I’ve invited here. Then, there are the social clubs, online social networking, etc. And family, extended family, etc.

    And, I’m an introvert!!!

    Interesting theory. I wonder who I should drop since I’m well over my limit….

  10. Carol Gee

    Grant, I have found this post and comments very thought-provoking. I’ll add my “two bits worth.” “Social contacts,” it seems to me, are those people with whom we keep in touch because we want to, not because we should. Other words are perhaps more accurate for the latter – associate, acquaintance, contact, neighbor, friend-of-a-friend, etc. Using “friend” as a category is a risky business, because being a friend brings expectations of acceptance, reciprocity, intimacy, etc. Thus, my true friends know all, or most all, of my secrets and love me anyway.

  11. Fabrizio

    As a professor and consultant I spend most of my time in classes and groups and I have noticed that Dunbar number suffers some kind of asymmetry: on the whole I meet and share time with almost 2000 people per year. The number of people course participants meet is usually less than 2000 and perhaps more close to the Dunbar number: this brings to the fact that I receive a lot of invitations on Linkedin etc from people that consider themselves as related to me and that I can hardly remember. How could you define this situation?

  12. Bri

    Reducing human contact and human relationships to a congealed mathematical number is, indeed, the oddest thing I have yet to read in a blog. Why actually bother with this? Are our lives so quantity-based and -nourished that we have to extend that way of thinking even to our most fundamentally human things? Hmm.

  13. linda

    This concept of the Dunbar number interests me in the context of a move, 6 years ago to a very small, relatively isolated town. I found the number of people with whom i was expected to engage in conversation which included personal information skyrocketing, whether i wanted it to or not. These interactions often felt oppressively effluvial, and yet, their intimate nature made them difficult to resist/avoid. Meanwhile, i increasingly use the internet for conversation which is more interesting and substantial. I find myself feeling greater intimacy with those who share their careful thoughts, but whom i never imagine physically meeting, or sometimes, even interacting with electronically, than to those whose stories i hear when i’m trying to buy groceries, but must be cordial with. I think often about the real meaning of that word, cordial. As well as the evolving meaning of the word friend.

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