Limits to Social Networks

The Dunbar number was first calculated by the anthropologist Robin Dunbar. For most purposes it shows that around 150 is the largest number which can form a cohesive network. This applies to companies, villages, academics, and any other and is based on the capacity of the human neocortex. In order to do this, he calculated that the group has to spend about 42% of its time on social grooming. In theory, computer software allows us to reduce this time as well reduce the dependance on propinquity. However, there is no evidence that this really happens. People with too many people in their social circle simply do not have the closeness and reciprocity of a genuine social network.

As a group becomes larger, smaller sub-groups form and it becomes hard work to build and maintain linkages betwen them.