Social norms and the complexity of human cooperation

The prevalence of cooperation among human societies is a puzzle that has caught the eye of researchers from multiple fields. Why is that people are selfless and often incur costs to aid others? Theoretical and experimental works have shown that status and reputations can provide solutions to the cooperation conundrum. These elements are often framed in the context of indirect reciprocity, which constitutes one of the most elaborate mechanisms of cooperation discovered so far. By helping someone, individuals may increase their reputation, which can change the predisposition of others to help them in the future. The reputation of an individual depends, in turn, on the social norms that establish what characterizes a good or bad action. Such norms are often so complex that an individual’s ability to follow subjective rules becomes im portant. Here I will present a mathematical framework — grounded on game theory and stochastic birth-death processes — capable of identifying the key pattern of the norms that promote cooperation, and those that do so at a minimum complexity. This combination of high cooperation and low complexity suggests that simple moral principles, and informal institutions based on reputations, can elicit cooperation even in complex environments.
This is a joint work with Fernando P. Santos (Princeton University) and Jorge M. Pacheco (Universidade do Minho)