Group size and settlement

Abstract

Social science comes in three forms: structural, interpretive and quantitative. Social anthropology is, in essence, composed of the first two, but quantitative studies on the relation between brain size and group size in primates have shown us clues about the size of communities of our hominin ancestors. These, in turn, have suggested the key to understanding issues in communication, and in particular the origins of language and of human kinship structures. In this chapter, I shall concentrate primarily on the first of these correlations (community size) and its implication for proto-human and human settlement. The origins of language are the subject of chapter 6, and my own theory of the relations among all these things, including especially kinship structures, must wait until chapter 8. The correlation between brain size and group size In 1993, Leslie Aiello and Robin Dunbar showed that there was a correlation between neocortex size and group size, at least among primates. Following their original article (Aiello and Dunbar 1993), further work by Dunbar revealed that the correlation worked for general brain size as well as for neocortex size. Calculations revealed too that the ‘natural’ group size for humans should be about 150, a figure that became known as ‘Dunbar's number’. Chimps spend about 20 per cent of their time grooming; humans spend about 20 per cent of their time in social interaction, most of it in conversation (Dunbar2001: 190–1). As group size increases, the necessity for grooming relationships to become linguistic ones also increases.