A Theoretical Approach to Norm Ecosystems: Two Adaptive Architectures of Indirect Reciprocity Show Different Paths to the Evolution of Cooperation

Frontiers in Physics

Yamamoto, Hitoshi¹  Okada, Isamu²  Sasaki, Tatsuya³  Uchida, Satoshi⁴ 

[1] Faculty of Business Administration, Rissho University, Japan;Faculty of Business Administration, Soka University, Japan;Faculty of Mathematics, University of Vienna, Austria;Research Center for Ethi-Culture Studies, RINRI Institute, Japan

关键词: Evolutionary game thoery;    evolution of cooperation;    Indirect reciprocity;    social norms;    ecosystems;    adaptive systems;   

DOI  :  10.3389/fphy.2018.00014

学科分类：物理（综合）

来源: Frontiers

【 摘 要 】

Indirect reciprocity is one of the basic mechanisms to sustain mutual cooperation, by which beneficial acts are returned, not by the recipient, but by third parties. This mechanism relies on the ability of individuals to know the past actions of others, and to assess those actions. There are many different systems of assessing others, which can be interpreted as rudimentary social norms (i.e., views on what is “good” or “bad”). In this paper, impacts of different adaptive architectures, i.e., ways for individuals to adapt to environments, on indirect reciprocity are investigated. We examine two representative architectures: one based on replicator dynamics and the other on genetic algorithm. Different from the replicator dynamics, the genetic algorithm requires describing the mixture of all possible norms in the norm space under consideration. Therefore, we also propose an analytic method to study norm ecosystems in which all possible second order social norms potentially exist and compete. The analysis reveals that the different adaptive architectures show different paths to the evolution of cooperation. Especially we find that so called Stern-Judging, one of the best studied norms in the literature, exhibits distinct behaviors in both architectures. On one hand, in the replicator dynamics, Stern-Judging remains alive and gets a majority steadily when the population reaches a cooperative state. On the other hand, in the genetic algorithm, it gets a majority only temporarily and becomes extinct in the end.

【 授权许可】

CC BY