Contemporary · Network Theory · Paper

Dunbar's Number

Robin Dunbar · 1992

"Dunbar proposed humans can maintain roughly 150 stable social relationships, capped by neocortex size — beyond that, groups need hierarchy, rules, or substructure to stay coherent."

The idea

Dunbar correlated primate neocortex size with group size and predicted human groups stabilize around 150 — the largest village that still runs on gossip instead of formal structure.

Why it works

The takeaway — recall it first

Reed's Law & Group-Forming Networks

"Reed argued that tools that let users form groups — not just connect one-to-one or broadcast one-to-many — have value that scales as 2^n, vastly outpacing Metcalfe's n², because the number of possible subgroups explodes."

David P. Reed · EssayContinue→