| The phenomenon of cooperation is central to a wide array of scientific disciplines. Not only is it key to explaining some of the most fundamental questions of biology and sociology, but it is also a cornerstone of understanding and successfully overcoming social dilemmas at multiple scales of human society. In addition, cooperation is considered crucial to any hope of long-term sustainable occupation of the earth by humans. Drawing on a broad interdisciplinary literature from biology, sociology, economics, political science, anthropology, law, and international policy analysis, this study uses computational methods to meld two disparate approaches to explaining cooperation---individual incentives and social structure. By maintaining a high level of abstraction results have broad applicability, ranging from colonies of social amoebae or ants to corporations or nations interacting in markets and policy arenas. In all of these cases, actors in a system with no central controller face a trade-off between individual goals and the needs of the collective. Results from evolutionary simulations of simple economic games show that when individual incentives, in the form of punishment, are coupled with social structure, especially complex social networks, cooperation evolves quite readily despite traditional economic predictions to the contrary. These simulation results are then synthesized with experimental work of others to present a challenge to standard, narrow definitions of rationality. This challenge asserts that, by defining rational actors as absolute utility maximizers, standard rational choice theory lacks an evolutionary context and typically ignores regard that agents may have for others in the local environment. Such relative considerations become important when potential interactions of a society's individuals are not broad and random, but are governed by emergent social networks as they are in real societies. Finally, analysis of the implications of these findings to efficacy of international environmental agreements suggest that conventional strategies for overcoming global social dilemmas may be inadequate when other-regarding preferences influence national strategies. |
