The 150 Myth

You actually know more people than you think

All the literature and studies that claim that people can only build relationships with maximum of 150 other people is only half true. The “150” number is often referred to as the Dunbar number after anthropologist Robin Dunbar. As covered in Gladwell’s Tipping Point and CommonSenseAdvice:

Dunbar has developed an equation, which works for most primates, in which he plugs in what he calls the neocortex ratio of a particular species – the size of the neocortex relative to the size of the brain – and the equation gives us the maximum expected group size for each species. For humans, the max group size is 147.8, or about 150. This figure seems to represent the maximum amount of people that we can have a real social relationship with – knowing who another human is and how they relate to us.

Dunbar’s number is often misinterpreted to mean that you can only remember information on 150 people. But that’s not accurate, especially with the help of technology and other social utilities. Traditionally this 150 number meant the average person can only have a deep and meaningful relationship with 150 people.

But most relationships aren’t deep and meaningful … and they need not be bidirectional. If you just want to keep up on someone’s life (and know the ins and outs of where they are working, who they are dating, and when they are doing, you can easily keep track of thousands of people … and you do.

Even outside of using any external or web utilities, the human brain has the capacity to keep billions of discreet pieces of information. To better understand this, we can look at vocabulary:
According to study by Paul Nation and Robert Waring, most educated people in the United States have a vocabulary of at least 20,000 English words. Each word has a denoted and connoted meaning, many have a story (past tense, plural, etc), and often they invoke a picture. We have relationship with words much like we do with people, yet have a connection with 20,000 of them is not uncommon.

And not only do we keep track of words, we keep track of people.

Are you a sports fan? When I was in high school I could tell you the stats of almost every major league baseball player. I had a “relationship” with all of them (even though none of them ever heard of me).

And any avid reader of Us Magazine or Pop Sugar has an intimate relationship with hundreds (if not thousands) of stars. Many people know more about Britney Spears than they do about their next door neighbor. Or maybe you are a political junkie. You’ll know the ins and outs and the total biographies of Bill Clinton, Winston Churchill, Martin Luther King, and George Washington.

A person even has direct relationships with thousands of people over the years from your teachers in grade school to members of a softball team. My guess is that the average educated person can track over 10,000 people (though it would be tough to do a study to prove it) and people who are connectors and use internet tools might be able to track 30,000. and yes, that’s a lot more than 150!

Back to Dunbar … Dunbar’s number is probably a minimum, not a maximum, number of social relationships a human can have. If you are in a “tribe”, splitting into 150 person units makes sense. But if you are a social human, you can potentially be a part of many “tribes” and build different relationships and experiences in all of them. Back in prehistoric times, we may have only had the opportunity to be a part of one clan, but today we can be a part of many.

8 thoughts on “The 150 Myth

  1. Moti Karmona

    Deep and meaningful relationship isn’t poking, following or remembering someone face in your virtual social tools.
    IMHO, 150 “Dunbar’s Friends” is the the upper limit (and not minimum) of those few “real”, trusted and known people in your huge / “shallow” online (/offline) social network.
    About the myth: I think the number is even lower these days since our “tribes” are much smaller in modern life.

  2. Bryan Jones

    I think that the uncertainty around Dunbar’s number reflects the massive changes that have evolved around social management. It’s hard to believe that true “one to many” social networks are less than a decade old (starting with SocialNet in this definition). The advent of these social networks has allowed individuals the ability to manage a relationship with little or no energy – no longer is getting together, having a phone call, or even sending an email required to know what someone in your extended network is doing.
    However, that has caused a huge problem. All of a sudden, people are able to passively manage massive amounts of relationships, and yet, like Moti mentions above, they aren’t deep and meaningful. Rather, these passive relationships strain the definition of “relationship”. Until the tools exist to make real world interactions as easy as online interactions, 150 accurately represents the maximum number of “active relationships” that can be managed at one time. These tools are coming, and as those tools become more prevalent, Dunbar’s number will become an antiquated reminder of how things were prior to the evolution of digital social tools.

  3. Tom Cole

    Without weighing in as to whether Dunbar’s number should be 150, and what it represents, I will say that people vary widely along almost every dimension. Not only do people fall along a continuum of physical characteristics of height and weight, also mental capabilities. So if Dunbar’s number exists (whether as an average, minium, or maximum), I suspect that the number might be 150 for some people, but 50 or 300 for others. There likely is a Dunbar spectrum with a wide variance between the ends.

  4. Darwin Redshield

    Interesting points… I would bet that most people who spend most of their time diluting their social knowledge with Pop Sugar and Social Networks lose out on any real relationships.
    I think that many people are beginning to confuse the concepts of those 150 relationships and those 20,000 words (ala thinking they are friends with Britney Spears or someone they follow on Facebook).

  5. Lt Col Matt Isler, USAF

    Well-done, Auren. Another example of the 150-member ceiling is church growth, well-addressed by MacDonald in Darwin’s Cathedral (, also an excellent reference for religious systems and group selection). An obvious challenge to leaders growing or running organizations beyond the 150-person mark is designing culture, values, and processes that keep the organization integrated as tribal pressures pull the organization apart. Military units accept (and encourage) tribal growth, but have (finally) developed the joint values and task-organization processes to integrate tribes for mission accomplishment.

  6. Dan Erwin

    Don’t know about the 150 number. But I do know that my biological and early tribal experiences were too small and constricting.
    Social network studies are emphasizing the value of distant networks, rather than personal (“birds of a feather”) networks. Intelligence development is readily enhanced by such networks.
    Ronald Burt has the smarts on social networks: Structural Holes, and Brokerage and Closure.
    Tribal politics is the bugaboo of the American culture–and scares the bejesus out of me.

  7. Patricia Appelquist

    Honestly, 150 is a low number, when I started some silly tradition of sending holiday cards after co workers (50) neighbors (35) businesses I patronage and know on a relative good basis (47) then distant friends ( people that know my family and occasionally communicated with )( 25) then my social network / email groups (85) then the really distant people (business cards I picked up but don’t remember the person -65) that is roughly 300 people -yeah postage sucks the problem is working the number to increase and strengthening those relationships otherwise everyone would get an email card and call it good.

  8. John Klepac

    The number 150 struck me as exceptionally low at first, since I’ve got over 900 Facebook friends and am on several forums besides, and with most of my friends on Facebook alone I could easily give some basic information on them and know what they look like. This isn’t what Dunbar’s number signifies, though. I’ve got my family, a few small groups of friends, and only a handful of people known only online with whom I actually maintain meaningful relationships – if anything 150 seems like a high average. In that sense, the number isn’t a myth, but studies about it are titled very boldly (one said that, above 150, Facebook friends are “meaningless,” which is profoundly ignorant of the value of back-burner relationships), and the reason it’s so low is that we simply don’t have enough time for more people, not that our brains couldn’t handle it.


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