Evolution of cooperation in social dilemmas: Signaling internalized norms

The article suggests a new explanation for cooperation in large, unstructured societies that avoids the restrictions required in most previous attempts. Our explanation deals with the role of internalized norms. Even internalized norms, i.e. norms that alter the perceived utility from acting in a cooperative or uncooperative way, will not help to overcome a dilemma in an unstructured society, unless individuals are able to signal their property of being a norm bearer. Only when having the norm may be communicated in a reliable way, can the picture change. We derive necessary and sufficient conditions for cooperation to be part of an asymptotically stable equilibrium of an evolutionary dynamics of signaling norm internalization, behavior and norm adoption. These conditions put the signaling costs of norm-adopters and non-adopters, the strength of the social norm and two parameters measuring the cost of cooperation into relation with each other.