How competition drove social complexity: the role of war in the emergence of States, both ancient and modern

The origin of human ultrasociality - the ability to cooperate in huge groups of genetically unrelated individuals - has long interested evolutionary and social theorists. In this article, we use cultural group or multilevel selection theory to explain how cultural traits needed to sustain large-scale complex societies necessarily arose as a result of competition among cultural groups. We apply the theory at two key particular junctures: (i) the emergence of the first States and hierarchical societies, and (ii) the Rise of Modern Nation-States and the associated Great Divergence in incomes between the West and the “Rest” that began in the eighteenth century.