The Dunbar Dilemma
Reading Time: 8 minutes
To make the most out of the time you spend reading this, pause a moment to collect some data in your brain. It might make the rest of your life more efficient.
How many humans did you interact with in the last 24 hours?
Of those people how many did you communicate with repeatedly in the last week, month, or year?
Categorize all these people into three concentric circles. It may help to envision a circular target. Greater frequency of interaction = closer to the bullseye.
Now on to the part where you become more efficient. Do not be put off by the brief bit of science that follows. For those that have never heard of the Dunbar number, I will provide some background.
In 1992 a British anthropologist by the name of Robin Dunbar published a paper in the Journal of Human Evolution. This paper compared the average brain size of modern humans to that of 38 different primate genera (think homo in homo-sapiens). Data on average brain size was regressed against a variety of behavioral and ecological variables in an attempt to find some sort of correlation. The regression analysis found no connection between brain size and any of the ecological variables but what it did find is fascinating. Dunbar’s paper titled “Neocortex size as a constraint on group size in primates” declared that social group size in primates was a function of brain volume.
The infamous Dunbar number comes straight from this study. It predicted that the optimal human social group size is somewhere between 100-250 and is most often referenced as 150. If you’re still reading at this point your mind is probably spinning with implications just as mine was when I first stumbled upon this fascinating number.
Think back to the exercise you performed just a moment ago. How many individuals did you group into the bullseye?
Your high-frequency group is most likely smaller than 10 people and is made up of family, coworkers, and close friends. You’ve probably heard the saying “You are the sum of the 5 people you spend the most time with” and now you know the science behind it. The names of these people are probably at the top of your notifications list and have been there consistently for years or even decades. It is extremely important to identify when one of the people in this circle becomes a negative drain on your life and it is even more important to act on these observations. You must make a conscious effort to push net-negative individuals into one of the outer circles or cease contact entirely. Your innermost circle must be curated often and with great precision.
Your middle circle is an important place for social connections and friends of friends. This group can be thought of as extended family and is the most valuable because it should include enough people to satisfy your intrinsic human desire for community. Ideally, this group is diverse and linked by the shared values that you personally hold. You may be satisfied with a relatively small middle group or you may maintain relatively close relationships with dozens. Regardless of how many people you require to stave off the symptoms of loneliness is it important to curate this group carefully as well.
The final outermost circle is the most dangerous. At first glance, this group may seem extremely large. Does it encompass all of your Facebook friends and Twitter followers? How many of the people that you scroll past on your social media feeds do you truly know? Consider that the ancient human equivalent to this circle would have included no more than 1-2 neighboring tribes. In recent history prior to the digital age, this group would be defined along the same lines that defined labor unions, church congregations, and local chapters of service organizations (Rotary International, Elks Lodges, Shiners International). Now as a result of digital network effects we have the ability to share our third circle with hundreds and thousands. In practice, the vast majority of these interactions lack any meaningful value yet we sustain them out of habit. The good news is the lack of strong ties should make this group the easiest to curate. Make cuts to this group ruthlessly and don’t be discouraged by the natural feeling of restraint. This feeling evolved over thousands of years to remind humans not to discard relationships too easily. Realize that platforms like Facebook have hacked this feeling.
I pick on social media often when I discuss the Dunbar number because admittedly it is the lowest hanging fruit. Don’t be discouraged if you have found meaningful connections in the online world. Just remember that your brain has social limits and no software can help you overcome this.
Be motivated by the fact that once you have thinned your tribe you will have much more time to invest in your two more important inner circles. You’ll find that the people closest to you will relish your renewed attention and you will reap great dividends from your investments. I hope this exercise prompts you to consider any overextension in your social network. Learn to curate your circles on a regular basis and be the director of your own reality instead of coasting through life at the whims of others like Truman Burbank.
You’ve made it to the end and if you are still enthralled by the number 150 I recommend you check out the resources linked below. I invite any feedback or criticism and you can contact me here.
Robin Dunbar’s original paper "Neocortex size as a constraint on group size in primates".
Forbes Article about friendships in the digital age.
