Dunbar's Number

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Dunbar's Number is a theoretical limit on the number of close social contacts an individual human can have. It is based on data from other primate groups where there is a strong correlation between group size and the size of the brain's neocortex. Thus, extrapolating from the human cranium would put Dunbar's Number somewhere between 100 and 200.

This has huge import in the modern day of "web 2.0", where we all seem to interact with thousands of relative strangers on a daily basis. The number of these people we actually know anything about, or could relate to, might be constrained to this range.

Dunbar's predictions for previous stages of hominid evolution[edit]

Using estimates for the brain size of early humans, and extrapolating from this relationship, Dunbar, along with Leslie Aiello predicted the cognitive group size for earlier stages of hominid evolution. While the original numbers are more specific and go into decimal points, they are rounded off by Steven Mithen as follows:[1][2]

  • Homo erectus - 111
  • Archaic Homo sapiens - 131
  • Homo neanderthalensis - 144
  • Australopithecus spp. - 67
  • Homo habilis - 82

By comparison, chimpanzees have a mean cognitive group size of 60.

The Monkeysphere[edit]

The monkeysphere is a term coined by David Wong, editor of Cracked. The idea is based on Dunbar's Number with the premise that people tend to dehumanize those outside of their particular "Monkeysphere":

Most of us do not have room in our Monkeysphere for our friendly neighborhood sanitation worker. So, we don't think of him as a person. We think of him as The Thing That Makes The Trash Go Away.
—David Wong[3]

The argument goes on to make three recommendations as to how this knowledge can be incorporated into a more enlightened worldview: T.R.Y.

First, TOTAL MORON. That is, accept the fact THAT YOU ARE ONE. We all are.

That really annoying person you know, the one who's always spouting bullshit, the person who always thinks they're right? Well, the odds are that for somebody else, you're that person. So take the amount you think you know, reduce it by 99.999%, and then you'll have an idea of how much you actually know regarding things outside your Monkeysphere.

Second, UNDERSTAND that there are no Supermonkeys. Just monkeys. Those guys on TV you see, giving the inspirational seminars, teaching you how to reach your potential and become rich and successful like them? You know how they made their money? By giving seminars. For the most part, the only thing they do well is convince others they do everything well.

No, the universal moron principal established in No. 1 above applies here, too. Don't pretend politicians are somehow supposed to be immune to all the backhanded fuckery we all do in our daily lives and don't laugh and point when the preacher gets caught on video snorting cocaine off a prostitute's ass. A good exercise is to picture your hero--whoever it is--passed out on his lawn, naked from the waist down. The odds are it's happened at some point. Even Gandhi may have had hotel rooms and dead hookers in his past.

And don't even think about ignoring advice from a moral teacher just because the source enjoys the ol' Colombian Nose Candy from time to time. We're all members of varying species of hypocrite (or did you tell them at the job interview that you once called in sick to spend a day leveling up on World of Warcraft?) Don't use your heroes' vices as an excuse to let yours run wild.

And finally, DON'T LET ANYBODY simplify it for you. The world cannot be made simple. Anyone who tries to paint a picture of the world in basic comic book colors is most likely trying to use you as a pawn.


Since the complexity of each individual personality makes each relationship more complex in itself, it can be argued that increased intelligence/brain complexity does not increase the number of possible relationships. Furthermore, there is no clear difference in group size between apes and human hunter-gatherers[4] (although the quality of each relationship of course differs significantly). Studies of computer networks have given much higher numbers.[5] In addition, that animals tend to have a particular group size does not necessarily mean that they are cognitively unable to have a larger size, and statistical analysis requires a several further assumptions.

See also[edit]

External links[edit]


  1. Mithen, S. Prehistory of the Mind, 132
  2. Mithen, S. Prehistory of the Mind, 107
  3. The monkeysphere
  4. Hunter-gatherer groups tend to be between 15 and 40 individuals
  5. Often exceeding 200 and sometimes close to 300