Indirect reciprocity (IR) is an important mechanism for promoting cooperation among self-interested agents. Simplified, it means: “you help me, therefore somebody else will help you” (in contrast to direct reciprocity: “you help me; therefore I will help you”). IR can be achieved via reputation and norms. However, it was often argued that IR only works if reputations are public and does not do so under private assessment (PriA). Yet, recent papers suggest that IR under PriA is feasible, and that it has more variety and ways to improve, than have been considered before.

Indirect reciprocity is an important mechanism for promoting cooperation among self-interested agents. Simplified, it means you help me, therefore somebody else will help you (in contrast to direct reciprocity: you help me, therefore I will help you). Indirect reciprocity can be achieved via reputation and norms. Strategies relying on these principles can maintain high levels of cooperation and remain stable against invasion, even in the presence of errors. However, this is only the case if the reputation of an agent is modeled as a shared public opinion. If agents have private opinions and hence can disagree if somebody is good or bad, even rare errors can cause cooperation to break apart. This paper examines a novel approach to overcome this private information problem, where agents act in accordance to others’ expectations of their behavior (i.e. pleasing them) instead of being guided by their own, private assessment. As such, a pleasing agent can achieve better reputations than previously considered strategies when there is disagreement in the population. Our analysis shows that pleasing significantly improves stability as well as cooperativeness. It is effective even if only the opinions of few other individuals are considered and when it bears additional costs.