Kristopher Smith
Department of Psychology
University of Pennsylvania

Hadza hunter-gatherers and the evolution of human cooperation

Cooperation among humans differs from other species in scope and scale, and explaining how humans evolved this propensity to cooperate remains a challenge. Numerous theories and models have been developed to answer this question and they all share the same fundamental solution: positive phenotypic assortment. Cooperation can only evolve if the benefits of cooperation preferentially flow between those who cooperate. Now, a central challenge is determining which theories best explain assortment using ecologically relevant data for the setting of human evolution. Here, I provide insight into the evolutionary origins of cooperation using data from one of the few remaining hunter-gatherer populations in existence – the Hadza of Northern Tanzania. Using longitudinal data of behavior in economic games and reputation among peers, I examine how two different class of models, social norms and partner choice, fare in explaining cooperation among the Hadza.