Dunbar’s Number in the Era of Social Media

By Guy Higgins

I recently came across an article, Maintaining Relationships: The Fallacy of Dunbar’s Number. The article was written by Brad McCarty. The title instantly attracted my attention because I’m a real believer in Dunbar’s Number and I wanted to find out if I was mistaken – was there really some solid evidence that Robin Dunbar was wrong in his conclusion that there is a maximum effective size to the social group that a human can maintain. (Dunbar is the evolutionary psychologist and anthropologist who uncovered evidence that there is a maximum effective size to a social network that human beings can maintain – i.e. Dunbar’s Number.)

I want to start with some background on Dunbar’s Number itself. As noted, Dr. Dunbar is an evolutionary psychologist and anthropologist, and he began the research that resulted in his number by observing the size of social groups maintained by various anthropoids. It is important to recognize that the social groups he studied established and maintained close or intimate relationships. In no way were these group relationships casual or based on infrequent interactions. He used various mathematical analyses to create a rough relationship between brain size and social group size. That yielded Dunbar’s Number for humans – I’ve seen assertions that Dunbar’s Number is as high as 253 (I’m impressed with the exactness of this one) and as low as 150. I suspect that there is, in fact a range that depends on the capacities of individual humans.

Mr. McCarty opens his article by stating that Robin Dunbar derived his number by studying Bill Gore’s company (he’s the guy who developed Gore-Tex after buying the rights to Teflon from Dupont). Bill Gore worked on the premise that organizations larger than 250 people were too big for everyone to work together well, and dictated that his company office buildings would have parking lots with 250 or fewer parking places (Malcolm Gladwell in his book, The Tipping Point, quotes 150 parking places). When the lots filled up, it was time to spin off a new company. McCarty’s assertion for the origin of Dunbar’s Number is interesting, but completely at odds with Wikipedia and other data – including Dunbar’s own research. It appears that McCarty used Gladwell as his source.

McCarty asserts in his article that social media such as Facebook and LinkedIn have changed our capacity to establish and maintain social groups. He notes that the average size of a LinkedIn group is in excess of 500 (I’m one of those people who has over 500 links), and that the average Facebook user has 338 “friends.” Like Arte Johnson in the old Laugh In skits, I find that “veerrryyy eenteresting – but dumb.” The social groups based on LinkedIn and facebook are hardly what I would categorize as close or intimate social groups. In fact, there are people in my LinkedIn connections with whom I have had no interactions since the original connection. Dunbar asserts, and I tend to agree, that his number is driven by the human capacity for maintaining close relationships. I’ll define a close relationship as one in which a person knows everyone in their social group and knows what those group members like and dislike, what they are doing and what their strengths and weaknesses are. “Technology” (meaning, in this case, computer programs, algorithms and the Internet) is not going to change our innate ability to keep that kind of information fresh. Clicking an icon on a screen and reading posts and tweets is not establishing and maintaining a close or intimate relationship. That requires more effort – possibly even regular face-to-face contact (absence may make the heart grow fonder, but it probably also makes the “ties that bind” grow weaker).

I must, in the interest of transparency, admit that I don’t see a great deal of good coming from the explosion of social media. It seems to me to be creating a huge time sink with little or no benefit since most of the online interaction results in extremely shallow relationships. I think that Mr. McCarty’s post was aimed more at getting clicks than at any serious attempt to discuss the validity of Dunbar’s Number. I think that Dr. Dunbar provided valuable insight into human behavior, and social media isn’t changing that behavior.




One thought on “Dunbar’s Number in the Era of Social Media

  1. I couldn’t agree more with your observations on little good coming from the explosion of social media. In the interest of transparency the only social media in which I participate is LinkedIn and have less than 20 connections on that platform.

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