The Dunbar Number as a Limit to Group Sizes

So Dunbar proposed a novel idea: the size of a species’ brain determines the optimal size of their social groups. Maintaining relationships, argued Dunbar, requires brain power. More relationships require more neurons. Extrapolating his straight line from primate brains to human brains, he found that the optimal human group size, if this hypothesis

real issue is not group size as such but bonded social relationships.

There is, they suggested, a limit on the number of people we can feel sympathy for, and this seems to set a limit on other groupings where close psychological interaction is required.

Dunbar’s number plays a certain role in the ensemble-like interaction of the large number of participants on the web. Robin Dunbar, in his research into the brains of primates and the organisation of groups,[54] determined the number of constant social connections that human is capable of maintaining. This number is on average 150 contacts (100 to

Brigham Young, Bill Gore, Malcolm Gladwell, and Robin Dunbar may have been onto something. For typical real-world values of the control parameters there is, in fact, a sudden change in incentives around the magic number 150. At that size, the balance of forces in the tug-of-war changes, and the system suddenly snaps from favoring a focus on loonsho

estimated that there was an upper limit at around 2,000 on the number of faces we could put names to.

Sociological research has shown that the maximum ‘natural’ size of a group bonded by gossip is about 150 individuals. Most people can neither intimately know, nor gossip effectively about, more than 150 human beings. Even today, a critical threshold in human organisations falls somewhere around this magic number.