Thirty years ago, John Dunbar, Professor of Evolutionary Psychology, proposed the social brain hypothesis which posited a relationship between brain size and group size with Dunbar’s Number setting this at 150 social connections for humans. The number has proved to be remarkably consistent across both ancient groupings, in the bronze Age and Anglo-Saxon villages as well as more recent networks including on-line gaming environments, Facebook Groups, telephone calling networks and Christmas card lists.
Dunbar has not been without his critics, particularly those who assert that human behaviour is culturally determined and cannot be assessed through the same biological rules as primates and the presence of social networking platforms like LinkedIn which allow us to maintain many more relationships. These claims have been refuted by Dunbar who says that they reflect a failure to understand the model. The 150 number refers to quality relationships and not acquaintances which go up to 1500 people we can recognize. He also cites neuroimaging studies showing a correlation between the size of the individual’s social network and the default mode neural network, the brain circuit which manages social relationships.
Dunbar’s number is of importance in the work we do and is perhaps most relevant with its smaller numbers rather than the bigger. Dunbar proposes a graded set of relationships beginning with 5 loved ones, 15 good friends and 50 friends. When we consider clients who are socially isolated and whose ecogram is dominated by red fracture lines, with few green lines denoting alliance we recognize a world that is devoid of those close connections which protect us from premature death, poor physical and mental health, and decreased life satisfaction. Removal of collective cognition, a shared social brain is clearly bad for us.
While our task as practitioners is to remediate or negate the lines of fracture and strengthen or develop those of connection, we may in the short term occupy one of those central positions. This relationship then become a place from which the client can build new connections so, in time we can vacate that space for someone who can occupy it in a more permanent fashion.