Dynamic indirect reciprocity: The influence of personal reputation and group reputation on cooperative behavior in nested social dilemmas

The indirect reciprocity theory suggested that the cues of reputational consequences determine the scope of indirect reciprocity and influence whether individuals decide to interact with others regardless of group identity. However, in more complex intergroup environments, there is no clear answer as to how indirect reciprocity guides intergroup cooperation. Based on this, the study used Intergroup Parochial and Universal-Cooperation (IPUC) to construct in-group interaction scenarios and explore the influence of reputation on different cooperative behaviors from both individual and group perspectives. The study found: (1) at the individual level, the influence of personal reputation on different cooperative behaviors is limited by group identity, and ingroup favoritism always exists, supporting the viewpoint of Bounded Generalized Reciprocity; (2) at the group level, group reputation promotes universal cooperation and suppresses parochial cooperation, regardless of group type, consistent with the Unbounded Indirect Reciprocity. The study supported and extended indirect reciprocity theory, providing a reference for understanding group relations.