Note — Apr 10, 2022

A Sequence of Dunbar-Like Numbers

Yesterday a random thought popped into my head. Is there a sequence of Dunbar-like numbers—“a suggested cognitive limit to the number of people with whom one can maintain stable social relationships” (150)—for larger and larger groups? In a nice bit of synchronicity, I ended up on Matt Webb’s site this morning, and his top post (featured below) is an excellent, quick, but deeper look at Dunbar’s research. It turns out that he went both smaller, with five, 15, and 50, and higher with tribes between 500 and 2500 members.

Which is kind of where I was going with my Dunbar-like numbers. Maybe not everyone is built to live in a village where everybody knows your name. What’s a more comfortable size? Three, four, five Dunbars? We then get away from “this is what our brains evolved into,” to more subjective terrain, but what’s the ‘best’ size for a city? ≅One million? Five? Fifteen? What’s the ‘best’ size for a country? Highly subjective again, but maybe there are some solid, researched numbers to follow in that sequence?

For example, Scandinavian countries are, by various metrics, often seen as fantastic places to live with very egalitarian societies. Norway, Denmark, and Finland are all around five and a half million people, Sweden is at ten and a half. Outside of scandies, Switzerland is at eight and a half, and stable Costa Rica, with no army, a good standard of living, and happy people? Five million. Random? Indicative of a sweet spot between five and ten? Cultural? BS?

If we slide another way, what if Westphalian countries are not the way to go? Would there be ideal sizes for a mesh of interconnected city-states? What’s the size of ‘mother nodes,’ and secondary and tertiary ones? Where does it connect back down to the three-four-five Dunbar villages above?

What if then, instead of made up and arbitrary hypothetical cities and villages, we wonder about directions for the next few decades? What are the best sizes for more autonomous places? Let’s say today the average city imports 90% of what’s used there, and you want to go more circular and autonomous, are the ‘best’ sizes for a village and a city still the same?

Basically, if the Dunbar number identifies a sweet spot for a circle of stable relationships, what are the other rings around that, and which factors might modify them?