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Casual evidence as well as daily experience suggest that many people have a strong aversion against being the "sucker" in social dilemma situations. As a consequence, those who cooperate may be willing to punish free-riding, even if this is costly for them and even if they cannot expect future benefits from their punishment activities. A main purpose of(More)
People are reciprocal if they reward kind actions and punish unkind ones. In this paper we present a formal theory of reciprocity. It takes into account that people evaluate the kindness of an action not only by its consequences but also by its underlying intention. The theory is in line with the relevant stylized facts of a wide range of experimental(More)
This paper studies risk attitudes using a large representative survey and also a complementary field experiment based on a representative subject pool. Using a question asking people about their willingness to take risks " in general " , we find that gender, age, height, and parental background have an economically significant impact on willingness to take(More)
Any opinions expressed here are those of the author(s) and not those of the institute. Research disseminated by IZA may include views on policy, but the institute itself takes no institutional policy positions. The Institute for the Study of Labor (IZA) in Bonn is a local and virtual international research center and a place of communication between(More)
1 We provide evidence that long-term relationships between trading parties emerge endogenously in the absence of third party enforcement of contracts and are associated with a fundamental change in the nature of market interactions. Without third party enforcement, the vast majority of trades are initiated with private offers and the parties share the gains(More)
We analyze the consequences of control on motivation in an experimental principal-agent game, where the principal can control the agent by implementing a minimum performance requirement before the agent chooses a productive activity. Our results show that control entails hidden costs since most agents reduce their performance as a response to the(More)
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(More)
While confounding factors typically jeopardize the possibility of using observational data to measure peer effects, field experiments offer the potential for obtaining clean evidence. In this paper we measure the output of subjects who were asked to stuff letters into envelopes, with a remuneration completely independent of output. We study two treatments.(More)
One lingering puzzle is why voluntary contribu tions to public goods decline over time in experimental and real-w orld settings. We show that the decl ine of cooperation is driven by individual preferences for im perfect conditional cooperation. Many people's desire to contribute less than oth ers, rather than changing beliefs of what others will contr(More)
The interaction between Arabidopsis and the biotrophic oomycete Peronospora parasitica (downy mildew) provides an attractive model pathosystem to identify molecular components of the host that are required for genotype-specific recognition of the parasite. These components are the so-called RPP genes (for resistance to P. parasitica). Mutational analysis of(More)