hence competitive pressure is higher. By contrast, levels of cooperation are very similar across areas. This indicates that … scarcity does not hamper cooperation, at least as long as a sub-survival level has not been reached. Our data further reveal a … "falling behind" is particularly salient. -- competition ; natural resource scarcity ; antisocial behaviour ; cooperation …

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 anti-social, harming cooperative …

determinants of norm enforcement. -- norm enforcement ; social norms ; field experiment ; altruistic punishment ; cooperation …