We show experimentally that fairness concerns may have a decisive impact on the actual and optimal choice of contracts in a moral hazard context. Bonus contracts that offer a voluntary and unenforceable bonus for satisfactory performance provide powerful incentives and are superior to explicit...

In this paper we report on a principal-agent experiment where the principal can choose whether to rely on an unenforcable bonus contract or to combine the bonus contract with a fine if the agent's effort falls below a minimum standard. We show that most principals do not use the fine and that...

Engelmann and Strobel (AER 2004) claim that a combination of efficiency seeking and minmax preferences dominates inequity aversion in simple dictator games. This result relies on a strong subject pool effect. The participants of their experiments were undergraduate students of economics and...

Lecture on the first SFB/TR 15 meeting, Gummersbach, July, 18 - 20, 2004: We report on several experiments on the optimal allocation of ownership rights. The experiments confirm the property rights approach by showing that the ownership structure affects relationship-specific investments and...

Chapter written for the Handbook of Reciprocity, Gift-Giving and Altruism

In recent years, many social scientists have claimed that trust plays an important role in economic and social transactions. Despite its proposed importance, the measurement and the definition of trust seem to be not fully settled, and the identification of the exact role of trust in economic...

In this paper, we argue that important labor market phenomena can be better understood if one takes (i) the inherent incompleteness and relational nature of most employment contracts and (ii) the existence of reference-dependent fairness concerns among a substantial share of the population into...

In recent years, many social scientists have claimed that trust plays an important role in economic and social transactions. Despite its proposed importance, the measurement and the definition of trust seem to be not fully settled, and the identification of the exact role of trust in economic...

In a recent paper, Hart and Moore (2008) introduce new behavioral assumptions that can explain long term contracts and important aspects of the employment relation. However, so far there exists no direct evidence that supports these assumptions and, in particular, Hart and Moore's notion that...

Most economic models are based on the self-interest hypothesis that assumes that all people are exclusively motivated by their material self-interest. In recent years experimental economists have gathered overwhelming evidence that systematically refutes the self-interest hypothesis and suggests...