Contributions published at Microeconomics and Experimental Economic Research (Ernst Fehr)

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. In this paper we provide clear and unambiguous experimental evidence for the behavioral relevance of fairness intentions. Our results indicate that the attribution of fairness intentions is important both in the domain of negatively reciprocal behavior and in the domain of positively reciprocal behavior. This means that reciprocal behavior cannot be fully captured by equity models that are exclusively based on preferences over the distribution of material payoffs. Models that take into account players' fairness intentions and distributional preferences are consistent with our data while models thatnfocus exclusively on intentions or on the distribution of material payoffs are not.

In this paper we show that a simple model of reciprocal 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 the rule. However, when communication or informal sanctions are available appropriation behavior is more efficient. Our analysis shows that these regularities arise naturally when a fraction of the subjects exhibits reciprocal preferences.

We investigate to what extent contribution decisions to a public good depend on the contributions of others. We employ a novel experimental technique that allows us to elicit people's willingness to be conditionally cooperative, i.e., to contribute more to the public good the more the other beneficiaries contribute. We find that about a third of subjects' contribution schedules is characterized by complete free-riding. However, a majority of 50 percent of the subjects displays conditional cooperation. Our results can explain why in most repeated public goods experiments subjects initially cooperate while towards the final periods cooperation declines to very low levels

Many of the most important choices in people's lives have an inter-temporal dimension, i.e., these choices are associated with a flow of benefits or costs that accrue in the future. In addition, such choices are frequently habit- forming. Yet, little is known about habit-forming inter-temporal choice behavior. This paper reports the results of an inter-temporal choice experiment with habit-formation. Subjects' choices deviate systematically from individually optimal decisions in the direction of over consumption. This over- consumption is partly driven by loss avoidance, comparable to a real life situation in which addicted people consume addictive substances only in order to overpower withdrawal symptoms. Our results thus reject the theory of rational addiction.

Money illusion means that people behave differently when the same objective situation is represented in nominal terms rather than in real terms. This paper shows that seemingly innocuous differences in payoff representation cause pronounced differences in nominal price inertia indicating the behavioral importance of money illusion. In particular, if the payoff information is presented to subjects in nominal terms, price expectations and actual price choices after a fully anticipated negative nominal shock are much stickier than when payoff information is presented in real terms. In addition we show that money illusion causes asymmetric effects of negative and positive nominal shocks. While nominal inertia is quite substantial and long-lasting after a negative shock, it is rather small after a positive shock.

This paper shows that reciprocity has powerful implications for many economicndomains. It is an important determinant in the enforcement of contracts and social norms and enhances the possibilities of collective action greatly. Reciprocity may render the provision of explicit incentive inefficient because the incentives may crowd out voluntary co-operation. It strongly limits the effects of competition in markets with incomplete contracts and gives rise to noncompetitive wage differences. Finally, reciprocity it is also a strong force contributing to the existence of incomplete contracts.n

The author reports on a series of experiments designed to investigate the factor of incentive mechanisms in the case of private provisions of public goods. In the Control treatment, there was no mechanism so that subjects faced strong free-riding incentives. In the so-called Falkinger mechanism treatment, the author implemented the Falkinger mechanism. The studies explored the impact of the mechanism in different economic environments. Results showed that the proposed incentive mechanism is very promising. Section I of the paper introduces the mechanism to be examined. Section II discusses the experimental design. Empirical results are provided in Section III, and Section IV interprets these results followed by a summary.

This paper examines how the presence of a non-negligible fraction of reciprocally fair actors changes the provision of incentives through contracts. We provide experimental evidence that principals have a strong preference for less complete contracts although the standard self-interest model predicts that they should prefer the more complete contract. Our theoretical analysis shows that fairness concerns can explain this preference for less completeness. Fair principals keep their promises which provides strong pecuniary incentives through an incomplete contract. Selfish principals free-ride and exploit the agents. Counter-intuitively, selfish agents are induced to work by an incomplete contract while fair agents shirk.

"This paper shows that identical offers in an ultimatum game generate systematically different rejection rates depending on the other offers that are available to the proposer. This result casts doubt on the consequentialist practice in economics to define the utility of an action solely in terms of the consequences of the action irrespective of the set of alternatives. It means, in particular, that negatively reciprocal behavior cannot be fully captured by equity models that are exclusively based on preferences over the distribution of material payoffs. Models that take into account players’ fairness intentions and distributional preferences are consistent with our data while models that focus exclusively on intentions or on the distribution of material payoffs are not."

"Money illusion means that people behave differently when the same objective situation is represented in nominal or in real terms. To examine the behavioral impact of money illusion we studied the adjustment process of nominal prices after a fully anticipated negative nominal shock in an experimental setting with strategic complementarity. We show that seemingly innocuous differences in payoff presentation cause large behavioral differences. In particular, if the payoff information is presented to subjects in nominal terms, price stickiness and real effects are much more pronounced than when payoff information is presented in real terms. The driving force of differences in real outcomes is subjects’ expectation of higher nominal inertia in the nominal payoff condition. Due to strategic complementarity, these expectations induce subjects to adjust rather slowly to the shock."

This paper provides evidence that free riders are heavily punished even if punishment is costly and does not provide any material benefits for the punisher. The more free riders negatively deviate from the group standard the more they are punished. As a consequence, the existence of an opportunity for costly punishment causes a large increase in cooperation levels because potential free riders face a credible threat. We show, in particular, that in the presence of a costly punishment opportunity almost complete cooperation can be achieved and maintained although, under the standard assumptions of rationality and selfishness, there should be no cooperation at all. We also show that free riding causes strong negative emotions among cooperators. The intensity of these emotions is the stronger the more the free riders deviate from the group standard. Our results provide, therefore, support for the hypothesis that emotions are guarantors of credible threats.

There is strong evidence that people exploit their bargaining power in competitive markets but not in bilateral bargaining situations. There is also strong evidence that people exploit free-riding opportunities in voluntary cooperation games. Yet, when they are given the opportunity to punish free-riders, stable cooperation is maintained although punishment is costly for those who punish. This paper asks whether there is a simple common principle that can explain this puzzling evidence. We show that if some people care about equity the puzzles can be resolved. It turns out that the economic environment determines whether the fair types or the selfish types dominate equilibrium behavior.

This paper presents an experimental examination of the Falkinger (1996) mechanism for overcoming the free-rider problem. The basic idea of the mechanism is that deviations from the mean contribution to the public good are taxed and subsidized. The mechanism has attractive properties because (i) it induces higher contributions to the public good and can implement an efficient level of contributions as a Nash equilibrium, (ii) the government budget is always balanced irrespective of the level of individual contributions, (iii) it is simple and policy makers need only little information to implement the mechanism. To examine the empirical properties of the mechanism we conducted a large series of experiments. It turns out that the introduction of the mechanism generates immediate and large efficiency gains. This result is robust throughout many different experimental settings. Moreover, in the presence of the mechanism the Nash equilibrium is a rather good predictor of behavior.