Abstract

Why are primates so social compared to other mammals and why are so many species monogamous? Evolutionary anthropologists aim to identify the drivers of behavioural change, particularly social behaviour across human and non-human primates, to answer these kinds of questions. However, behaviour does not fossilise well. We must therefore resort to probabilistic methods to try to reconstruct the past. Fortunately, the latest Bayesian phylogenetic comparative methods allow us to reconstruct ancestral behaviour, test for correlated evolution between traits, and determine relative timing of trait change to identify drivers of social evolution. I apply these techniques to uncover the traits that are implicated in social change across all primates and also in humans, where archaeological and written records are absent.