Understanding the roots of human cooperation among strangers is of great importance for solving pressing social … dilemmas and maintening public goods in human societies. We study the development of cooperation in 929 young children, aged 3 … to 6. In a unified experimental framework, we examine which of three fundamental pillars of human cooperation – direct …

We investigate how group boundaries, and the economic environment surrounding groups, affect altruistic cooperation and … harm those who defect, encouraging a norm of cooperation towards the group. Adding competition between groups causes even … stronger in-group cooperation, but also a qualitative change in punishment: punishment becomes antisocial, harming cooperative …

- to eleven-year old primary school children in the city of Meran, we find that cooperation generally increases with age …, but that the gap between cooperation among in-group members and cooperation towards children speaking another language is …