Calling Dunbar’s Numbers
Pádraig MacCarron, Kimmo Kaski, Robin Dunbar
4 Aug 2016
The social brain hypothesis predicts that humans have an average of about 150 relationships at any given time.
Within this 150, there are layers of friends of an ego, where the number of friends in a layer increases as the emotional closeness decreases.
Individuals do not give equal weight to each relationship and evidence from the social brain hypothesis suggests that ego networks are structured into a sequence of layers with the size of each layer increasing as emotional closeness decreases (Dunbar 1998, Hill and Dunbar 2003).
The mean number of friends in each has been found to be around 5, 15, 50 and 150 in the cumulative layers (i.e. on average 10 people in the second layer to make a total of 15) (Zhou et al. 2005, Hamilton et al. 2007).