This paper investigates the driving forces behind informal sanctions in cooperation games and the extent to which theories of fairness and reciprocity capture these forces. We find that cooperators' punishment is almost exclusively targeted towards the defectors but the latter also impose a...

Informal sanctions are a major determinant of a society's social capital because they are key to the enforcement of implicit agreements and social norms. Yet, little is known about the driving forces behind informal sanctions. We systematically examine the determinants of informal sanctions by a...

Informal sanctions are a major determinant of a society's social capital because they are key to the enforcement of implicit agreements and social norms. Yet, little is known about the driving forces behind informal sanctions. We examine systematically the determinants of informal sanctions by a...

Field evidence suggests that people belonging to the same group often behave similarly, i.e., behavior exhibits social interaction effects. We conduct a laboratory experiment that avoids the identification problem present in the field and allows us to study the behavioral logic of social...

Field evidence suggests that agents belonging to the same group tend to behave similarly, i.e., behavior exhibits social interaction effects. Testing for such effects raises severe identification problems. We conduct an experiment that avoids these problems. The main design feature is that each...

This paper presents a formal theory of reciprocity. Reciprocity means that people reward kind actions and punish unkind ones. The theory takes into account that people evaluate the kindness of an action not only by its consequences but also by the intention underlying this action. The theory...

In this paper we show that a simple model of fairness preferences explains major experimental regularities of common pool resource (CPR) experiments. The evidence indicates that in standard CPR games without communication and without sanctioning possibilities inefficient excess appropriation is...