Evolution of Human Behaviour
We are particularly interested in the factors that drove the evolution of large-scale human cooperation and teamwork. Humans are often cited as among the most cooperative of animals, but the flipside is that they are also among the most discriminatory, hostile, and violent towards people they perceive as outsiders. The idea that warfare among ancestral human bands increased social cohesion and promoted cooperation has been around for centuries, and was discussed extensively by Darwin in his 1871 book The Descent of Man. Intergroup conflict is also widespread in other animals, and varies in frequency and intensity for reasons that are not well understood. In the last twenty years the idea that warfare shaped the evolution of human societies has been formalised in population genetic and game theoretical models which examine the spread of cooperative alleles on an evolutionary time scale, i.e., over hundreds or thousands of generations. But we have surprisingly little theory to understand the behavioural causes and consequences of intergroup conflict – how individuals and groups should respond to attacks, or to rapid changes in their ecological and social environment that occur within the lifetime of group members. Together with Rufus Johnstone I am working on new theoretical models to address this issue, with the aim of testing them in humans and other social organisms, from social insects to primates.