My research interests are in the evolution of social systems in humans and other primates. I use Bayesian phylogenetic methods to explore the evolution of social and mating systems, marriage and kinship and investigate the causes of changes in those traits. My work has focused on the evolution of sociality and the causes for the emergence of monogamy in primates and the drivers of change in human kinship and marriage patterns. I am currently investigating the evolution of sociality in primates and the origins of lethal violence in humans. I am now starting a major project looking at how changes in information technology, such as writing, printing and computer technology, impact cooperation in human societies.