An apology is a strong and cheap device to restore social or economic relationships thathave been disturbed. In a laboratory experiment we find that harmdoers use apologies inparticular if they fear punishment and when their intentions cannot be easily inferred. Afteroffenses with ambiguous...

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...

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...

Typically, laboratory experiments suffer from homogeneous subject pools and selfselection biases. The usefulness of survey data is limited by measurement error and by the questionability of their behavioral relevance. Here we present a method integrating interactive experiments and...

One lingering puzzle is why voluntary contributions to public goods decline over time in experimental and real-world settings. We show that the decline of cooperation is driven by individual preferences for imperfect conditional cooperation. Many people's desire to contribute less than others,...

In this paper, we investigate the effects of competition on bargained outcomes. We show that the neglect of either fairness concerns or decision errors will prevent a satisfactory understanding of how competition affects bargaining. We conducted experiments which demonstrate that introducing a...

Recently developed models of fairness can explain a wide variety of seemingly contradictory facts. The most controversial and yet unresolved issue in the modeling of fairness preferences concerns the behavioral relevance of fairness intentions. Intuitively, fairness intentions seem to play an...

All known human societies establish social order by punishing violators of social norms. However, little is known about how the brain processes the punishment threat associated with norm violations. We use fMRI to study the neural circuitry behind social norm compliance by comparing a treatment...

Promises are one of the oldest human-specific psychological mechanisms fostering cooperation and trust. Here, we study the neural underpinnings of promise keeping and promise breaking. Subjects first make a promise decision (promise stage), then they anticipate whether the promise affects the...