Modelling Primate Social Order: Ultimate and Proximate Explanations

For many species of primates, arguably including humans, social behaviour can be characterised along an axis usually described as running from egalitarian to despotic. Despotic societies are characterised by a strict hierarchy with very few aggressive interactions, but where aggression occurs it is typically violent and usually unilateral from dominant to subordinate. Egalitarian societies have less well-defined hierarchies; frequent, bilateral, but less violent aggression, and a large repertoire of reconciliation behaviours. In this paper we describe our approach to understanding the selective pressures that results in these different social organisations. Our technique focuses on agent-based modelling of the closely related species in the genus macaca. To simplify the problem we have split the models into ultimate and proximate causes, using two different ABM tools for the two different problems. This is work in progress — here we explain our approach, and describe preliminary results from the ultimate cause model.