"Integrated Indirect Reciprocity and the Evolution of the Open Society"Sasaki, TatsuyaIn diverse human societies, maintaining openness is pivotal for sustainable development. While traditional game-theoretical frameworks have predominantly focused on the evolution of cooperation through reciprocity, leading to complete cooperation, they have largely overlooked the dynamics of diverse cooperation levels. Our study introduces a novel framework that integrates indirect reciprocity with the concept of generalized reciprocity, or ‘paying it forward.’ This approach uncovers evolutionary scenarios distinct from those posited in classical models of indirect reciprocity. Our analysis identifies a stable polymorphism between integrated reciprocators and unconditional defectors. The polymorphism is robust even in invasions by unconditional cooperators and pure forms of indirect or generalized reciprocity. Moreover, this polymorphic equilibrium retains its stability despite considering a certain finite level of complexity costs, a stark contrast to the classical monomorphic equilibrium of cooperation, which becomes unstable to invasions of unconditional cooperators. |
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