A key factor in determining the importance of group competition for within-group cooperation is the relative strength of between- and within-group competition. In our study, the effect of between-group competition was only as strong as within-group competition, but it was sufficient to radically increase cooperation within groups. There can be little doubt that stronger between-group competition would result in even higher levels of within-group cooperation, as cooperation then would be the most profitable strategy for both individuals and groups.Proceedings of The Royal Society B doi: 10.1098/rspb.2008.1060
Between-group competition and human cooperation
Mikael Puurtinen* & Tapio Mappes
A distinctive feature of human behaviour is the widespread occurrence of cooperation among unrelated individuals. Explaining the maintenance of costly within-group cooperation is a challenge because the incentive to free ride on the efforts of other group members is expected to lead to decay of cooperation. However, the costs of cooperation can be diminished or overcome when there is competition at a higher level of organizational hierarchy. Here we show that competition between groups resolves the paradigmatic ‘ public goods’ social dilemma and increases within-group cooperation and overall productivity. Further, group competition intensifies the moral emotions of anger and guilt associated with violations of the cooperative norm. The results suggest an important role for group conflict in the evolution of human cooperation and moral emotions.