Unfairness promotes the evolution of cooperation

Inequality is a ubiquitous phenomenon in real-world society. This investigation aims to study inequality in prisoner dilemma. Individuals contribute to a public pool and act ei-ther fairly or unfairly to share the public resource. The participator can either accept the allocation scheme to get a payoff that is better than nothing, or reject it to punish inequal-ity. In the case of discrete strategies, we find that both extreme inequality and fairness fail to optimize the spreading of cooperator, a moderate unfairness best favors the evolution of cooperation under the effects of cyclic dominance. In the case of continuous strategies, it is found that the population evolves into a less unfair state particularly for the coexistence of two strategies, and cooperators prevail by acting fairer than defectors in a spontaneous manner. Our work reveals that inequality impacts the evolution of cooperation significantly and highlights the importance of fairness and unfairness in enhancing the evolution of co-operation.(c) 2022 Elsevier Inc. All rights reserved.

Automated summary

In this study, researchers investigated inequality in the context of the prisoner's dilemma. They found that extreme inequality and fairness were both ineffective in promoting cooperation, while moderate unfairness was the most favorable for cooperation under cyclic dominance. Additionally, the population evolved into a less unfair state when two strategies coexisted, and cooperators prevailed by acting fairer than defectors in a spontaneous manner. This work highlights the significant impact of inequality on the evolution of cooperation and emphasizes the importance of fairness and unfairness in enhancing cooperation.