Principles of the evolution of human social structures: kinship and gift-giving

Anthropologists have long noted structural similarities among geographically distant societies. To investigate the origins of these patterns, I develop simple models of human interactions based on field observations, simulating the emergence of social structures. This talk focuses on two key topics. The first examines the evolution of kinship structures in clan societies [1, 2, 3]. By modeling kin and in-law cooperation alongside mating competition, I show how cultural groups with specific marriage rules spontaneously emerge. The second explores the transition of social organizations through competitive gift-giving [4, 5]. By modeling how gifts deliver material goods to recipients and confer social reputation upon donors, I demonstrate transitions across four phases—band, tribe, chiefdom, and kingdom—each characterized by distinct social networks and distributions of wealth and reputation. In both cases, I highlight the alignment between theoretical predictions and empirical observations, offering quantitative criteria and empirically measurable explanatory parameters for classifying social structures.