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

In this paper, we argue that important labor market phenomena can be better understood if one takes (a) the inherent incompleteness and relational nature of most employment contracts and (b) the existence of reference-dependent fairness concerns among a substantial share of the population into account. Theory shows and experiments confirm that, even if fairness concerns were to exert only weak effects in one-shot interactions, repeated interactions greatly magnify the relevance of such concerns on economic outcomes. We also review evidence from laboratory and field experiments examining the role of wages and fairness on effort, derive predictions from our approach for entry-level wages and incumbent workers' wages, confront these predictions with the evidence, and show that reference-dependent fairness concerns may have important consequences for the effects of economic policies such as minimum wage laws.

Are initial competitive advantages self-reinforcing, so that markets exhibit an endogenous tendency to be dominated by only a few firms? Although this question is of great economic importance, no systematic empirical study has yet addressed it. Therefore, we examine experimentally whether firms with an initial cost advantage are more likely to invest in marginal cost reductions than firms with higher initial costs. We find that the initial competitive advantages are indeed self-reinforcing, but subjects in the role of firms overinvest relative to the Nash equilibrium. However, the pattern of overinvestment even strengthens the tendency towards self-reinforcing cost advantages relative to the theoretical prediction. Further, as predicted by the Nash equilibrium, mean-preserving spreads of the initial cost distribution have no effects on aggregate investments. Finally, investment spillovers reduce investment, and investment is higher than the joint-profit maximizing benchmark for the case without spillovers and lower for the case with spillovers.

Purpose. To study extraocular muscle (EOM) function, the local physiologic contraction and elongation (deformation) along human horizontal EOMs were quantified using motion-encoded MRI. Methods. Eleven subjects (healthy right eye) gazed at a target that moved horizontally in a sinusoidal fashion (period 2s, amplitude +/-20 degrees ), during MR imaging with an optimized protocol. In addition, EOM longitudinal deformation of two patients with Duane's syndrome type I were analyzed. The horizontal EOMs and the optic nerve were tracked through 15 time frames and their local deformation was calculated. Eight segments were separated along the EOMs and compared for left-to-right and right-to-left eye movements. Results. In healthy subjects, the maximal EOM deformation was situated at approximately 2/3 of the muscle lengths from the scleral insertions. The EOM deformations were similar for the entire movement range as well as in both movement directions. In two patients with Duane's syndrome type I, the abnormal innervation of lateral rectus muscle affected specific EOM segments only. The posterior muscle segments contracted and the anterior muscle segments relaxed during adduction. Conclusions. Motion-encoded MRI is a useful technique to advance the understanding of the physiology and pathophysiology of EOMs in humans during eye movement.

Future events are uncertain by their very nature. Therefore, people's risk preferences are likely to play a role in the valuation of allegedly guaranteed future outcomes. We show that future uncertainty conjointly with people's proneness to nonlinear probability weighting generates a unifying framework for explaining many anomalies in intertemporal choice, such as hyperbolic discounting and subadditivity of discount factors. Moreover, our approach implies that higher uncertainty of future prospects increases the hyperbolicity of discount rates, suggesting that institutional deficiencies such as lack of contract enforcement, may be a source ofnhyperbolic discounting behavior. Based on an experiment with monetary incentives, we show that people's risk taking behavior is indeed a significant determinant of their time discounting behavior: Greater departures from linear probability weighting predict a stronger decline in impatience on the level of individual behavior.

It has long been recognized that there is considerable heterogeneity in individual risk taking behavior but little is known about the distributionnof risk taking types. We present a parsimonious characterization of risk taking behavior by estimating a finite mixture regression model for three different experimental data sets, two Swiss and one Chinese, over a large number of real gains and losses. We find two distinct types of individuals: In all three data sets, the choices of roughly 80% of the subjects exhibitnsignificant deviations from linear probability weighting, consistent with prospect theory. 20% of the subjects weight probabilities near linearly and behave essentially as expected value maximizers. Moreover, individuals are cleanly assigned to one type with probabilities close to unity. The reliability and robustness of our classification suggest using a mix of preference theories in applied economic modeling.

How does risk tolerance vary with stake size? This important question cannot be adequately answered if framing effects, nonlinear probability weighting, and heterogeneity of preference types are neglected. We show that the increase in relative risk aversion over gains cannot be captured by the curvature of the utility function. It is driven predominantly by a change in probability weighting of a majority group of individuals who exhibit more rational probability weighting at high stakes. Contrary to gains, noncoherent change in relative risk aversion is observed for losses. These results not onlynchallenge expected utility theory, but also prospect theory.

The article discusses and analyzes data from several economic experiments in a household survey with mothers of preschool children. The researchers measured competitiveness by giving the subjects the choice between competing in a tournament or receiving a piece rate for a real effort task. The subjects also participated in lottery choices, which enabled the researchers to assess their risk preferences. The relationship between social preferences and competitiveness in the sample of mothers of preschool children was analyzed. The hypothesis that egalitarian subjects aren't as likely to self-select into competitive environments, which can produce winners and losers, was tested. A negative relationship between egalitarian choices and self-selection into competition was found.

We study the impact of reputational incentives in markets characterized by moral hazard problems. Social preferences have been shown to enhance contract enforcement in these markets, while at the same time generating considerable wage and price rigidity. Reputation powerfully amplifies the positive effects of social preferences on contract enforcement by increasing contract efficiency substantially. This effect is, however, associated with a considerable bilateralisation of market interactions, suggesting that it may aggravate price rigidities. Surprisingly, reputation in fact weakens the wage and price rigidities arising from social preferences. Thus, in markets characterized by moral hazard, reputational incentives unambiguously increase mutually beneficial exchanges, reduce rents, and render markets more responsive to supply and demand shocks.

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 interactions has proven to be elusive. It is still not clear whether trust is just an epiphenomenon of good institutions or whether it plays an independent causal role capable of shaping important aggregate economic outcomes. In this paper, I rely on a behavioral definition of trust that enables us to relate it to economic primitives such as preferences and beliefs. I review strong biological and behavioral evidence indicating that trusting is not just a special case of risk-taking, but based on important forms of social preferences such as betrayal aversion. Behaviorally defined trust also opens the door for understanding national and ethnic trust differences in terms of differences in preferences and beliefs, and it suggests ways to examine and interpret a causal role of trust.

Every social group needs to decide when to provide public goods and how to allocate the costs among its members. Ideally, this decision would maximize the group’s net benefits while also ensuring that every individual’s benefit is greater than the cost he or she has to pay. Unfortunately, the economic theory of mechanism design has shown that this ideal solution is not feasible when the group leadership does not know the values of the individual group members for the public good. We show that this impossibility result can be overcome in laboratory settings by combining technologies for obtaining neural measures of value (functional magnetic resonance imaging–based pattern classification) with carefully designed institutions that allocate costs based on both reported and neurally measured values.

Damage to the ventromedial prefrontal cortex (VMPFC) impairs concern for other people, as reflected in the dysfunctional real-life social behavior of patients with such damage, as well as their abnormal performances on tasks ranging from moral judgment to economic games. Despite these convergent data, we lack a formal model of how, and to what degree, VMPFC lesions affect an individual’s social decision-making. Here we provide a quantification of these effects using a formal economic model of choice that incorporates terms for the disutility of unequal payoffs, with parameters that index behaviors normally evoked by guilt and envy. Six patients with focal VMPFC lesions participated in a battery of economic games that measured concern about payoffs to themselves and to others: dictator, ultima- tum, and trust games. We analyzed each task individually, but also derived estimates of the guilt and envy parameters from aggregate behavior across all of the tasks. Compared with control subjects, the patients donated significantly less and were less trustworthy, and overall our model found a significant insensitivity to guilt. Despite these abnormalities, the patients had normal expectations about what other people would do, and they also did not simply generate behavior that was more noisy. Instead, the findings argue for a specific insensitivity to guilt, an abnormality that we suggest characterizes a key contribution made by the VMPFC to social behavior.

A widely observed phenomenon in decision making under risk is the apparent overweighting of unlikely events and the underweighting of nearly certain events. This violates standard assumptions in expected utility theory, which requires that expected utility be linear (objective) in probabilities. Models such as prospect theory have relaxed this assumption and introduced the notion of a “probability weighting function,” which captures the key properties found in experimental data. This study reports functional magnetic resonance imaging (fMRI) data that neural response to expected reward is nonlinear in probabilities. Specifically, we found that activity in the striatum during valuation of monetary gambles are nonlinear in probabilities in the pattern predicted by prospect theory, suggesting that probability distortion is reflected at the level of the reward encoding process. The degree of nonlinearity reflected in individual subjects’ decisions is also correlated with striatal activity across subjects. Our results shed light on the neural mechanisms of reward processing, and have implications for future neuroscientific studies of decision making involving extreme tails of the distribution, where probability weighting provides an explanation for commonly observed behavioral anomalies.

Curiosity has been described as a desire for learning and knowledge, but its underlying mechanisms are not well understood. We scanned subjects with func- tional magnetic resonance imaging while they read trivia questions. The level of curiosity when reading questions was correlated with activity in caudate regions previously suggested to be involved in anticipated reward. This finding led to a behavioral study, which showed that sub- jects spent more scarce resources (either limited tokens or waiting time) to find out answers when they were more curious. The functional imaging also showed that curiosity increased activity in memory areas when subjects guessed incorrectly, which suggests that curiosity may enhance memory for surprising new information. This prediction about memory enhancement was confirmed in a behavioral study: Higher curiosity in an initial session was correlated with better recall of surprising answers 1 to 2 weeks later.

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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 interactions has proven to be elusive. It is still not clear whether trust is just an epiphenomenon of good institutions or whether it plays an independent causal role capable of shaping important aggregate economic outcomes. In this paper, I rely on a behavioral definition of trust that enables us to relate it to economic primitives such as preferences and beliefs. I review strong biological and behavioral evidence indicating that trusting is not just a special case of risk-taking, but based on important forms of social preferences such as betrayal aversion. Behaviorally defined trust also opens the door for understanding national and ethnic trust differences in terms of differences in preferences and beliefs, and it suggests ways to examine and interpret a causal role of trust.

Awards are increasingly popular in the corporate sector to motivate employees. Managers consider innovative human resource practices, such as awards, to be essential to enhance firm competitiveness. The prevalence and popularity of awards in the corporate sector suggest that awards fulfill important functions in principal‐agent relationships. This is contrasted with the paucity of academic research targeted at recognition programs. This thesis provides an extensive discussion of awards and demonstrates their effect on employee performance. Chapters 2 and 3 lay the theoretical foundation for why awards may motivate and discuss their relationship with other incentive instruments. Additionally, some insights into practitioners' perceptions of the topic are presented. Chapters 4 to 6 provide the empirical evidence. The field experiment presented in chapter 4 shows that productivity in a data entry job is significantly higher in workgroups where the two best employees can get an award in addition to the fixed wage that is identical for all workgroups. Chapter 5 reports the results of an econometric study using data on awards and employee performance from the call center of a large international bank. It can be shown that the performance of award winners is significantly higher than that of nonrecipients one month after the award is handed out. Chapter 6 sheds some light into what award features drive this effect by reporting the results of a vignette study with researchers at a research laboratory. The findings suggest that the publicity associated with winning an award is a major motivation force that drives people to aspire an award. Finally, Chapter 7 concludes.

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 small amount of competition to a bilateral ultimatum game – by adding just one competitor – induces large behavioral changes among responders and proposers, causing large changes in accepted offers. Models that assume that all people are self-interested and fully rational do not adequately explain these changes. We show that a model which combines heterogeneous fairness concerns with decision errors correctly predicts the comparative static effects of changes in competition. Moreover, the combined model is remarkably good at predicting the entire distribution of offers in many different competitive situations.