Network Structure and Social Complexity in Primates

Primates use social grooming to create and maintain coalitions. Because of this, individuals focus their time on a small number of individuals, and this means that in many cases group networks are not fully connected. I use data on primate grooming networks to show that three different social grades can be differentiated in terms of network structuring. These grades seem to arise from a glass ceiling imposed on group size by limits on the time available for social grooming. It seems that certain genera have managed to circumvent this constraint by a phase shift in the behavioural and cognitive mechanisms that underpin social relationships in a way that allows a form of multilevel sociality based on weak and strong ties not unlike those found in human social networks.