Social Cognition as a Constraint on Social Interaction

The social brain hypothesis offers an explanation for why primates should (a) have larger brains than other species and (b) differ so strikingly in terms of their cognitive abilities. In this chapter, I outline the social brain hypothesis and some of the evidence that has been adduced to support it, and then explore the extent to which possible cognitive constraints arising from brain volume might limit human social behaviour. I explore two particular aspects of human behaviour: the dynamics of conversation groups and social network size. Two conclusions are suggested by studies that we have undertaken. One is that there is a relationship between an individual's ability to cope with the extended layers of intentional tasks and the size of their social network. The other is that the hierarchical structure of our social networks, consisting of a series of expanding circles containing progressively more individuals, is a function of both the emotional intensity of relationships and the frequency of interaction.