Several experimental studies have shown that the crowding-out effect of monitoring may outweigh its disciplining effect through intrinsic motivation destruction, thereby reducing effort. However, most of these experiments use numeric effort tasks that subjects may not be intrinsically motivated to complete. This paper aims to analyze the incentive effects of monitoring using a real-effort task for which intrinsic motivation is more likely to exist. We conducted two similar experiments, in the lab in Montreal and in the field in Ouagadougou. In contrast to the lab, subjects in the field are unaware they are taking part in an experiment.

The following results are observed both in the lab and in the field. Relative to the baseline treatment, we find that our two monitoring treatments significantly increase effort, in line with agency theory. However, effort levels are not significantly different between the monitoring treatments. Finally, increasing the subjects’ wage is found to have no effect on effort.

We study the effects of closing price manipulation in an experimental market to evaluate the social harm caused by manipulation. We find that manipulators, given incentives similar to many actual manipulation cases, decrease price accuracy and liquidity. The mere possibility of manipulation alters market participants’ behavior, leading to reduced liquidity. We find evidence that ordinary traders attempt to profitably counteract manipulation. This study provides examples of the strategies employed by manipulators, illustrates how these strategies change in the presence of detection penalties and assesses the ability of market participants to identify manipulation.

Using data aggregated from seven papers that study repeated play in standard ultimatum games with either stranger or absolute stranger matching, we show that the behavior of responders changes with experience. High offers are more likely to be accepted with experience and low offers are more likely to be rejected. At the individual level, there is a negative relationship between the likelihood that a given offer is accepted and the size of the preceding offer. We compare the results with predictions generated by static models of distributional preferences, implicitly dynamic models of preferences with reciprocity, and explicitly dynamic models of adaptive learning. The data is most consistent with models of preferences with reciprocity.

Online labor markets have great potential as platforms for conducting experiments. They provide immediate access to a large and diverse subject pool, and allow researchers to control the experimental context. Online experiments, we show, can be just as valid—both internally and externally—as laboratory and field experiments, while often requiring far less money and time to design and conduct. To demonstrate their value, we use an online labor market to replicate three classic experiments. The first finds quantitative agreement between levels of cooperation in a prisoner's dilemma played online and in the physical laboratory. The second shows— consistent with behavior in the traditional laboratory—that online subjects respond to priming by altering their choices. The third demonstrates that when an identical decision is framed differently, individuals reverse their choice, thus replicating a famed Tversky-Kahneman result. Then we conduct a field experiment showing that workers have upward-sloping labor supply curves. Finally, we analyze the challenges to online experiments, proposing methods to cope with the unique threats to validity in an online setting, and examining the conceptual issues surrounding the external validity of online results. We conclude by presenting our views on the potential role that online experiments can play within the social sciences, and then recommend software development priorities and best practices.

In this paper we discuss laboratory experiments that address the problem of self-governance in an asymmetric commons dilemma. Small-scale irrigation systems that provide food for hundreds of millions of people around the world are probably the most common example of such dilemmas. Here, we formulate an abstract dilemma in which subjects make both a decision about investment in the provision of infrastructure associated with the use of a resource and about how much to extract from the common-pool resource made available by this infrastructure. The impact of inherent asymmetry in irrigation systems on the provision of a resource and the impact of communication on the capacity of the group to solve the two-level commons dilemma of cooperation and coordination based on the analysis of the experimental data are discussed.

This paper compares contributions to an experimental public good across the United States and Czech Republic, using a design that allows us to distinguish between altruism and decision error. Czech subjects contribute significantly more than American subjects, and further analysis reveals that this result cannot be attributed to the confounding effects of gender or decision error. Instead, preferences for altruism appear to differ across groups: Czechs are more altruistic than Americans and men are more altruistic than women.

In this paper, we report an experimental investigation of the effect of framing on social preferences, as revealed in a one-shot linear public goods game. We use two types of indicator to measure social preferences: self-reported emotional responses; and, as a behavioural indicator of disapproval, punishment. Our findings are that, for a given pattern of contributions, neither type of indicator depends on the Give versus Take framing that we manipulate. To this extent, they suggest that the social preferences we observe are robust to framing effects.

By providing incentives for sellers to act in a trustworthy manner, reputation mechanisms can mitigate moral-hazard problems when particular buyers and sellers interact infrequently. However, these mechanisms rely on buyers sharing their private information about sellers, and thus may suffer from too little feedback when provision is costly. We experimentally compare a standard feedback mechanism to one in which sellers can inspect a buyer's feedback-provision history, thus providing incentives to share private information even when costly. We find fairly high trust and trustworthiness in all markets, with buyers providing costly feedback, especially negative, sufficient to induce trustworthiness. However, feedback-provision histories did not improve outcomes, and at least weakly decreased trustworthiness with experienced participants, as this information enabled sellers to discriminate and ship less frequently to buyers lacking a reputation for information sharing.

Recent studies find that women are less competitive than men. This gender difference in competitiveness has been suggested as one possible explanation for why men occupy the majority of top positions in many sectors. In this study we explore competitiveness in children, with the premise that both context and gendered stereotypes regarding the task at hand may influence competitive behavior. A related field experiment on Israeli children shows that only boys react to competition by running faster when competing in a race. We here test if there is a gender gap in running among 7-10 year old Swedish children. We also introduce two female sports, skipping rope and dancing, to see if competitiveness is task dependent. We find no gender difference in reaction to competition in any task; boys and girls compete equally. Studies in different environments with different types of tasks are thus important in order to make generalizable claims about gender differences in competitiveness.

Over the last 25 years, more than a hundred dictator game experiments have been published. This meta study summarises the evidence. Exploiting the fact that most experiments had to fix parameters they did not intend to test, in multiple regression the meta study is able to assess the effect of single manipulations, controlling for a host of alternative explanatory factors. The resulting rich dataset also provides a testbed for comparing alternative specifications of the statistical model for analysing dictator game data. It shows how Tobit models (assuming that dictators would even want to take money) and hurdle models (assuming that the decision to give a positive amount is separate from the choice of amount, conditional on giving) provide additional insights.

Other-regarding preferences or decision errors are the main explanations put forward to justify contributions exceeding the non-cooperative optimum in VCM games. An alternative rationale relies on ambiguity aversion. Ambiguity aversion increases the perceived marginal benefit of own contributions, which in equilibrium will exceed the Nash level. We present a series of experiments testing this hypothesis. To control for other-regarding preferences, we run a two-player game in which a human player plays with a virtual agent. Players are assigned either to a risky setting (known probabilities of opponent's choices) or to an ambiguity setting (probabilities of opponent's contribution are vague). Results show that ambiguity affects contributions. However, attitude to ambiguity appears to be affected by the location of the aggregate Nash optimum inside the decision space.