Contributions in Merlin

We study indirect reciprocity and strategic reputation building in an experimental helping game. At any time only half of the subjects can build a reputation. This allows us to study both pure indirect reciprocity that is not contaminated by strategic reputation building and the impact of incentives for strategic reputation building on the helping rate. We find that while pure indirect reciprocity appears to be important, the helping choice seems to be influenced at least as much by strategic considerations. Strategic do better than non-strategic players and non-reciprocal do better than reciprocal players, casting doubt on previously proposed evolutionary explanations for indirect reciprocity.

We examine experimentally how Chief Executive Officers (CEOs) respond to incentives and how they provide incentives in situations requiring trust and trustworthiness. As a control we compare the behavior of CEOs with the behavior of students. We find that CEOs are consider-ably more trusting and exhibit more trustworthiness than students-thus reaching substantially higher efficiency levels than students. Moreover, we find that, for CEOs as well as for students, incentives based on explicit threats to penalize shirking backfire by inducing less trustworthy behavior-giving rise to hidden costs of incentives. However, the availability of penalizing incentives also creates hidden returns: if a principal expresses trust by voluntarily refraining from implementing the punishment threat, the agent exhibits significantly more trustworthiness than if the punishment threat is not available. Thus trust seems to reinforce trustworthy behav-ior. Overall, trustworthiness is highest if the threat to punish is available but not used, while it is lowest if the threat to punish is used. Paradoxically, however, most CEOs and students use the punishment threat, although CEOs use it significantly less.

People not only care about outcomes, they also value the procedures which lead to the outcomes. Procedural utility is a potentially important source of human well-being. This paper aims at introducing the concept of procedural utility into economics, and argues that it should be incorporated more widely into economic theory and empirical research. Three building blocks of a concept of procedural utility are outlined and it is suggested how procedural utility can be fruitfully integrated. Evidence from a broad range of social sciences is reviewed in order to show that procedural utility is a relevant concept for economics.

The paper evaluates the German health care reform of 1997, using the individual number of doctor visits as outcome measure and data from the German Socio- Economic Panel for the years 1995-1999. A number of modified count data models allow to estimate the effect of the reform in different parts of the distribution. The overall effect of the reform was a 10 percent reduction in the number of doctor visits. The effect was much larger in the lower part of the distribution than in the upper part.

This work gives a brief overview of the portfolio selection problem following the mean-risk approach first proposed by Markowitz (1952). We consider various risk measures, i.e. variance, value-at-risk and expected-shortfall and we study the efficient frontiers obtained by solving the portfolio selection problem under these measures. We show that under the assumption that returns are normally distributed, the efficient frontiers obtained by taking value-at-risk or expected-shortfall are subsets of the mean-variance efficient frontier. We generalize this result for all risk measures that can be written as a particular combination of mean and variance and we show that for these measures Tobin separation holds under some restrictions.

This paper presents an application of evolutionary portfolio theory to stocks listed in the Swiss Market Index (SMI). We study numerically the long-run outcome of the competition of rebalancing rules for market shares in a stock market with actual dividends taken from firms listed in the SMI. Returns are endogenous because prices are determined by supply and demand stemming from the rebalancing rules. Our simulations show that in competition with rebalancing rules derived from Mean-Variance Optimization, Maximum Growth Theory and Behavioral Finance, the evolutionary portfolio rule discovered in Hens and Schenk-Hoppé (2001) will eventually hold total market wealth. According to this simple rule the portfolio weights should be proportional to the expected relative dividends of the assets.

This paper reports the results of a series of competitive labour market experiments in which subjects have the possibility to reciprocate favours. In the high stake condition subjects earned between two and three times their monthly income during the experiment. In the normal stake condition the stake level was reduced by a factor of ten. We observe that both in the high and the normal stake condition fairness concerns are strong enough to outweigh competitive forces and give rise to non-competitive wages. There is also no evidence that effort behaviour becomes generally more selfish at higher stake levels. Therefore, our results suggest that, contrary to common beliefs, fairness concerns may play an important role even at relatively high stake levels.

"Recent evidence highlights the importance of social norms in many economic relations. However, many of these relationships are long-term and provide repeated game incentives for performance. We experimentally investigate interaction effects of reciprocity and repeated game incentives in two treatments (one-shot and repeated) of a gift-exchange game. In both treatments we observe reciprocity, which is strengthened in the repeated game. A detailed analysis shows that in the repeated game some subjects imitate reciprocity. Thus, reciprocity and repeated game incentives reinforce each other. Observed behaviour is robust against experience. We conclude that a long-term interaction is a “reciprocity-compatible” contract enforcement device."

Preise, Einkommen, und Nachfrage – die zentralen zu erklaerenden Variablen in den Wirtschaftswissenschaften sind objektiv messbar. Daneben gibt es jedoch zwei nicht minder zentrale Groessen, Erwartungen und Praeferenzen, die sich einer direkten objektiven Messung entziehen. Es sind subjektive Variablen, also solche, die von persoenlichen Meinungen und Erfahrungen bestimmt sind. Allerdings bedeutet dies nicht, dass sie ueberhaupt nicht messbar waeren. Ganz im Gegenteil enthalten typische Haushaltsbefragungen eine ganze Reihe von subjektiven Fragen, die ueber verschiedene Aspekte von Erwartungs- und Praeferenzbildung informieren. Im folgenden werde ich darstellen, welche Arten von subjektiven Variablen bisher in der empirischen Wirtschaftsforschung betrachtet wurden. Dann werde ich auf Probleme bei der Interpretation von subjektiven Variablen eingehen. Und schliesslich werde ich die wesentlichen Aspekte der oekonometrischen Modellbildung besprechen und zwei neue Modelle vorstellen.

This paper investigates if multinationals in.uence the political process through lobbying more effectively than national firms. First, I introduce a model which contrasts a multinational’s incentives for lobbying with those of a national firm. Then the effect of lobbying on the political decision is analyzed. I conclude that multinationals have smaller incentives to lobby because they have smaller stakes in national markets. But the effectiveness of lobbying by multinationals might be higher if the government cares much about production in the home country. The resulting regulation depends on the relative strength of these effects.