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In this paper we measure the effect of the inflation tax on economic activity and welfare within a controlled setting. To do so, we develop a model of price posting and monetary exchange with inflation and finite populations. The model, which provides a game–theoretic foundation to Rocheteau and Wright (2005)׳s competitive search monetary equilibrium, is used to derive theoretical propositions regarding the effects of inflation in this environment, which we test with a laboratory experiment that closely implements the theoretical framework. We find that the inflation tax is harmful – with cash holdings, production and welfare all falling as inflation rises – and that its effect is relatively larger at low inflation rates than at higher rates. For instance, for inflation rates between 0% and 5%, welfare in the two markets we consider (2[seller]×2[buyer] and 3×2) falls by roughly 1 percent for each percentage–point rise in inflation, compared with 0.4 percent over the range from 5% to 30%. Our findings lead us to conclude that the impact of the inflation tax should not be underestimated, even under low inflation.

In this paper, we compare participants in an artefactual field experiment in urban China with the survey population of migrants from which they were recruited. The experimental participants were more educated, more likely to lend money to friends, and worked fewer hours than the general population. They differ significantly from non-participants in terms of regression coefficients, such as the effects of wealth and marital status on the probability of being self-employed and distance migrated. We thus find that there was selection into our experiments on the basis of both observable characteristics and on unobserved differences in behavioral relations.

We study both theoretically and experimentally the set of Nash equilibria of a classical one-dimensional election game with two candidates. These candidates are interested in power and ideology, but their weights on these two motives are not necessarily identical. Apart from obtaining the well known median voter result and the two-sided policy differentiation outcome, the paper uncovers the existence of two new equilibrium configurations, called ‘one-sided’ and ‘probabilistic’ policy differentiation, respectively. Our analysis shows how these equilibrium configurations depend on the relative interests in power (resp., ideology) and the uncertainty about votersʼ preferences. The theoretical predictions are supported by the data collected from a laboratory experiment, as we observe convergence to the Nash equilibrium values at the aggregate as well as at the individual levels in all treatments, and the comparative statics effects across treatments are as predicted by the theory.

In an experiment with professionals from the financial services sector, we investigate the impact of a team incentive scheme on the recommendation quality of investment products when advisors benefit from advising lower quality products. Experimental results reveal that, when group affiliation is strong, inferior products are recommended significantly more often under team incentives than under individual incentives.

Evidence shows that real-effort investments can affect bilateral bargaining outcomes. This paper investigates whether similar investments can inhibit equilibrium convergence of experimental markets. In one treatment, sellers' relative effort affects the allocation of production costs, but a random productivity shock ensures that the allocation is not necessarily equitable. In another treatment, sellers' effort increases the buyers' valuation of a good. We find that effort investments have a short-lived impact on trading behavior when sellers' effort benefits buyers, but no effect when effort determines cost allocation. Efficiency rates are high and do not differ across treatments.

In this paper we reply to Binmore and Shaked's criticism of the Fehr–Schmidt model of inequity aversion. We put the theory and their arguments into perspective and show that their criticism is not substantiated. Finally, we briefly comment on the main challenges for future research on social preferences.

Researchers who have examined markets populated by “robot traders” have claimed that the high level of allocative efficiency observed in experimental markets is driven largely by the “intelligence” implicit in the rules of the market. Furthermore, they view the ability of agents (artificial or human) to process information and make rational decisions as unnecessary for the efficient operation of markets. This paper presents a new series of market experiments that show that markets populated with standard robot traders are no longer efficient if time is a meaningful element, as it is in all asset markets. While simple two-season markets with human subjects reliably converge to an efficient equilibrium, markets with minimally intelligent robot traders fail to attain this equilibrium. Instead, these markets overshoot the equilibrium and then crash below it. In addition to firmly establishing the role of trader intelligence in asset-market equilibrium, these experiments also provide insights into why bubbles and crashes are consistently observed in many asset-market laboratory experiments using human subjects.

Effort tasks are commonly used to assess individual investment and performance in an experimental setting. Although the tasks used are diverse, they are typically intended to be equivalent as far as they aim to generalize beyond the specific task. We compare an induced value effort task and three real effort tasks in a contest game. Results show that there is no equivalence across tasks in relation to how risk attitude, anxiety and gender predict performance.

Unfair intentions provoke negative reciprocity from others, making their concealment potentially beneficial. This paper explores whether people hide their unfair intentions from others and how hiding intentions is itself perceived in fairness terms. Our experimental data show a high frequency of cover-up attempts and that affected parties punish the concealment of intentions, establishing that people consider not only unkind intentions but also hiding intentions unfair. When choosing whether or not to hide intentions, subjects trade-off the lower expected punishment when the cover up of unfair intentions is successful against the higher expected punishment when cover up is unsuccessful. In an attempt to better understand fairness perceptions, we present a typology of punisher types and show that hiding unkind intentions is treated differently than unkind intentions, possibly establishing a behavioral category of its own.

It is an established fact that gay men earn less than other men and lesbian women earn more than other women. In this paper we study whether differences in competitive preferences, which have emerged as a likely determinant of labour market differences between men and women, can provide a plausible explanation. We conduct an experiment on a Dutch online survey panel to measure the competitiveness of gay, lesbian and straight panel members. For differences in competitiveness to partially explain sexual orientation differences in earnings, gay men would need to be less competitive than other men and lesbian women more competitive than other women. Our findings confirm this competitiveness hypothesis for men, but not for women. Gay men compete less than other men, while lesbian women compete as much as other women. Linking our experimental measure to survey data, we show that competitiveness is a significant predictor of earnings. Differences in competitiveness can account for a significant portion of the gay earnings penalty, but cannot explain the lesbian premium.

This paper reports data from three subject pools (n=717 subjects) using techniques based on those of Loewenstein, et al. (1989) and Blanco, et al. (2011) to obtain parameters, respectively, of stated and revealed inequality aversion. We provide a replication opportunity for those papers, with two innovations: (i) a design which allows stated and revealed preferences to be compared at the individual level; (ii) assessment of robustness of findings across subjects from a UK university, a Turkish university and Amazon Mechanical Turk. Our findings on stated aversion to inequality are qualitatively similar to those of Loewenstein, et al. in each of our subject pools, whereas there are notable differences between some of our findings on revealed preference and those of Blanco, et al. We find that revealed advantageous inequality aversion is often stronger than revealed dis-advantageous inequality aversion. In most subject pools, we find some (weak) correlation between corresponding parameters of stated and revealed inequality aversion.

Managers often use tournaments which motivate workers to compete for the top, compete to avoid the bottom, or both. In this paper we compare the effectiveness and efficiency of the corresponding incentive schemes. To do so, we utilize optimal contracts in a principal-agent setting, using a Lazear-Rosen type model that predicts equal effort and efficiency levels for the three mechanisms with the appropriate distribution of prizes. We test the model's predictions in a laboratory experiment and find that a mechanism which incorporates both competition for the top and away from the bottom produces the highest effort from agents, especially in contests of a relatively larger size. Avoiding being last is shown to produce the lowest variance of effort, be more effective and, in larger contests, more efficient than competing for the top. Finally, we show that behavior in all mechanisms is consistent with basic directional and reinforcement learning.

An influential body of scholarship argues that corruption behaves as a selffulfilling prophecy. The idea of this work is that levels of corruption emerge endogenously as a result of a society-wide coordination game in which ther individual returns to corrupt behavior are a function of how disposed towards corruption the other members of society are perceived as being. An empirical implication of this logic is that if one were to exogenously perturb beliefs about societal levels of corruption upward, willingness to engage in corruption should increase as a consequence. The current paper evaluates this claim by utilizing an information experiment embedded in a large-scale household survey conducted in the Gran Área Metropolitana (GAM) of Costa Rica from October 2013 to April 2014 (n=4200). Changes in beliefs about corruption were induced via the random assignment of an informational display depicting the increasing percentage of Costa Ricans who have experienced or directly observed an act of corruption (from 2006 to 2011). The paper finds that, on average, assignment to this display (relative to the control condition) increased the probability that a respondent would be willing to pay a bribe to a police officer by approximately 0. 04 to 0. 08, thereby providing supporting evidence for the self-fulfilling prophecy hypothesis.

We show that socio-economic status (SES) is a powerful predictor of many facets of a child's personality. The facets of personality we investigate encompass time preferences, risk preferences, and altruism, as well as crystallized and fluid IQ. We measure a family's SES by the mother's and father's average years of education and household income. Our results show that children from families with higher SES are more patient, tend to be more altruistic and less likely to be risk seeking, and score higher on IQ tests. We also discuss potential pathways through which SES could affect the formation of a child's personality by documenting that many dimensions of a child's environment differ systematically by SES: parenting style, quantity and quality of time parents spend with their children, the mother's IQ and economic preferences, a child's initial conditions at birth, and family structure. Finally, we use panel data to show that the relationship between SES and personality is fairly stable over time at age 7 to 10. Personality profiles that vary systematically with SES might offer an explanation for social immobility.

This paper studies gender differences in strategic situations. In two experimental guessing games - the beauty contest and the 11-20 money request game - we analyze the depth of strategic reasoning of women and men. We use unique data from an internet experiment with more than 1,000 participants. We find that men, on average, perform more steps of reasoning than women. Our results also suggest that women behave more consistently across both games.

The paper investigates the introduction of an institution, in form of an impartial authority (third party), into a two-person situation. The impartial authority can reward a stranger for acting according to a desired behavioral norm. The reward is costly for the authority and her behavior cannot be strategic, i.e., it cannot lead to higher earnings for her in a later stage. A trust game followed by a helping game is implemented. The trustee in the trust game becomes the recipient in the helping game. This paper demonstrates that positive strong indirect reciprocity can exist in one-shot settings (helpers transfer more money to their recipients the more these are trustworthy) and that positive strong indirect reciprocity is not diminishing if the reward can be anticipated. Furthermore, the positive strong indirect reciprocity is correctly anticipated and leads to higher trustworthiness in the treatment.

Self-regulatory organizations (SROs) can be found in education, healthcare, and other not-for-profit sectors as well as in the accounting, financial, and legal professions. DeMarzo et al. (2005) show theoretically that SROs can create monopoly market power for their affiliated agents, but that governmental oversight, even if less efficient than oversight by the SRO, can largely offset the market power. We provide an experimental test of this conjecture. For carefully rationalized parameterizations and implementation details, we find that the predictions of DeMarzo et al. (2005) are borne out.

This paper reports the results of an experiment on incentive contracts for teams. The agents, whose efforts are complementary, are rewarded according to a sharing rule chosen by the principal. Depending on the sharing rule, the agents confront endogenous prisoner's dilemma or stag-hunt environments. Our main findings are as follows. First, we demonstrate that ongoing interaction among team members positively affects the principal's payoff. Greater team cooperation is successfully induced with less generous sharing rules in infinitely repeated environments. Second, we provide evidence of the positive effects of communication on team cooperation in the absence of ongoing team interaction. Fostering communication among team members does not significantly affect the principal's payoff, suggesting that agents’ communication is an imperfect substitute for ongoing team interaction. Third, we show that offering low sharing rules can backfire. The agents are willing to engage in costly punishment (shirking) as retaliation for low offers from the principal. Our findings suggest that offering low sharing rules is perceived by the agents as unkind behavior and hence, triggers negative reciprocity.

This chapter presents some insights from basic behavioural research on the role of human pro-social motivation to maintain social order. I argue that social order can be conceptualized as a public good game. Past attempts to explain social order typically relied on the assumption of selfish and rational agents ("homo economicus"). The last twenty years of research in behavioural and experimental economics have challenged this view. After presenting the most important findings of recent research on human pro-sociality I discuss the evidence on three pillars of the maintenance of social order. The first pillar is internalized norms of cooperation, sustained by emotions such as guilt and shame. The second pillar is the behaviour of other people who typically are "conditional cooperators" willing to cooperate if others do so as well. This motivation can sustain cooperation if enough people cooperate but can jeopardise social order if many others follow selfish inclinations. The third pillar are sanctions meted out to anyone who does not cooperate; ideally punishment can work as a mere threat without being executed much. The chapter also presents some evidence on the cross-cultural variability of some findings, in particular with regard to punishment behaviour. The chapter concludes with remarks on future research.

This paper discusses the choice of the number of participants for within-subjects (WS) designs and between-subjects (BS) designs based on simulations of statistical power allowing for different numbers of experimental periods. We illustrate the usefulness of the approach in the context of field experiments on gift exchange. Our results suggest that a BS design requires between 4 to 8 times more subjects than a WS design to reach an acceptable level of statistical power. Moreover, the predicted minimal sample sizes required to correctly detect a treatment effect with a probability of 80% greatly exceed sizes currently used in the literature. Our results suggest that adding experimental periods in an experiment can substantially increase the statistical power of a WS design, but have very little effect on the statistical power of the BS design. Finally, we discuss issues relating to numerical computation and present the powerBBK package programmed for STATA. This package allows users to conduct their own analysis of power for the different designs (WS and BS), conditional on user specified experimental parameters (true effect size, sample size, number of periods, noise levels for control and treatment, error distributions), statistical tests (parametric and nonparametric), and estimation methods (linear regression, binary choice models (probit and logit), censored regression models (tobit)).

We summarize our two sets of controlled experiments designed to see whether single-sex classes within co-educational environments modify students' risk-taking attitudes. In Booth and Nolen (2012b), subjects are in school years 10 and 11, while in Booth et al. (2014), they are first-year university students randomly assigned to single-sex and co-educational classes. Both studies show that while on average females are significantly less likely than men to make risky choices, on exposure to single-sex environments they behave the same as the males. Thus, part of the observed gender difference in behaviour under uncertainty found in previous studies might reflect social learning rather than inherent gender traits. (JEL codes: C9, C91, C92, J16, D01, D80, J16, J24)

We experimentally investigate the extent to which social observability of one’s actions and the possibility of social non-monetary judgment affect the decision to engage in rule breaking behavior. We consider three rule breaking scenarios — theft, bribery and embezzlement — in the absence of any formal enforcement mechanism. By involving a student sample characterized by cultural heterogeneity due to immigration of ancestors to the US, we are able to investigate whether the effectiveness of informal social enforcement mechanisms is conditional on the cultural background of the decision-maker. A total of 52 countries are represented in our sample, ranging from Low Rule of Law countries such as Liberia and Nigeria to High Rule of Law countries such as Sweden and Norway. Our data provide evidence that people with different cultural backgrounds do respond differently to increased social observability of their actions. In particular, while subjects that identify culturally with a High Rule of Law country respond to social obervability and judgment by lowering their propensities to engage in rule breaking, subjects that identify with Low Rule of Law countries do not. Our findings suggest that development policies that rely purely on social judgment to enforce behavior may not work with Low Rule of Law populations.

Neutral framing is a standard tool of experimental economics. However, overly neutral instructions, which lack any contextual clues, can lead to strange behavior. In a contextless second price auction for a meaningless good, a majority of subjects enter positive bids -- a case of cognitive experimenter demand effect. Subjects bid positive amounts because this is what they think they are tasked with in the experiment. Adding a second auction that has a context drastically reduces the positive bids in the meaningless first auction by reducing the cognitive experimenter demand effect.

This paper studies optimal taxation in dynamic economies with increasing returns. We show that if there exists a stable open-loop Stackelberg equilibrium, the optimal rate of tax on capital income in the steady-state is negative in order to eliminate the wedge between the private and the social rate of return to capital. This result also holds when the government expenditure has a positive effect on production activities of the private agents. In contrast, if the government takes a feedback strategy and if the government budget is balanced in every period, then the optimal capital income taxation rule obtained under the open-loop strategy may be violated. It is, however, shown that if the government can borrow from the public, the negative capital income tax rule may be established even under the feedback policy rule.

Many laboratory experiments show that people are often altruistic or care for fairness. We present data that reveal a darker side of human nature. We introduce the joy-of-destruction game. Two players each receive an endowment and simultaneously decide on how much of the other player's endowment to destroy. Subjects play this game repeatedly. In one treatment, subjects can hide their destruction behind random destruction. In this treatment, money is destroyed in almost 40% of all decisions. We attribute this behavior to a visceral pleasure of being nasty. Under full information destruction is also observed, but rare. In this treatment, acts of destruction are followed by immediate retaliation., Working papers series, ISSN 2628-1724, 2008, Heft 37

We use experimental data to investigate what subjects have learned after participating in an economic experiment for many periods. At the end of our experiments subjects are given another experiment to perform which functions like a surprise quiz since they had not been informed about its existence before. The results of this surprise-quiz round, along with the time-series of their responses before the quiz, allow us to judge what they have learned. We find that depending on the manner in which subjects are paid, they attempt to learn different aspects of the experimental task and perform differently. Journal of Economic Literature Classification Numbers: C91, D83.

We develop a simple experimental setting to evaluate the role of the Taylor principle, which holds that the nominal interest rate has to respond more than one-for-one to fluctuations in the inflation rate. In our setting, the average infl ation rate fluctuates around the inflation target if the computerized central bank obeys the Taylor principle. If the Taylor principle is violated, then the average infl ation rate persistently deviates from the target. We find that these deviations from the target are less pronounced, if inflation rates cannot be as readily observed as nominal interest rates. This result is consistent with the interpretation that subjects underestimate the influence of inflation on the real return to savings if the infl ation rate is only observed ex post.

This study is the first economic experiment that tests the economic significance of the theory of psychological reactance (Brehm, 1966). For this purpose, I design an economic experiment in which subjects are asked to express their valuation of two-choice situations. In one case, subjects are given absolute freedom, whereas in another, the extent of their freedom of choice is limited. As the experimental data revealed, subjects’ valuation of free and limited choice situations did not differ significantly. Thus, in the experiment, the subjects did not display signs of reactance. In the end, the potential reasons of why the subjects did not exhibit reactance are discussed. The lessons derived from this study may serve as a future guide for testing the economic significance of the reactance theory.

Behavioral biases in forecasting, particularly the lack of adjustment from current values and the overall clustering of forecasts, are increasingly explained as resulting from the anchoring heuristic. Nonetheless, the classical anchoring experiments presented in support of this interpretation lack external validity for economic domains, particularly monetary incentives, feedback for learning effects and a rational strategy of unbiased predictions. We introduce an experimental design that implements central aspects of forecasting to close the gap between empirical studies on forecasting quality and the laboratory evidence for anchoring effects. Comprising more than 5,000 individual forecasts by 455 participants, our study shows significant anchoring effects. Without monetary incentives, the share of rational predictions drops from 42% to 15% in the anchor's presence. Monetary incentives reduce the average bias to one-third of its original value. Additionally, the average anchor bias is doubled when task complexity is increased, and is quadrupled when the underlying risk is increased. The variance of forecasts is significantly reduced by the anchor once risk or cognitive load is increased. Subjects with higher cognitive abilities are on average less biased toward the anchor when task complexity is high. The anchoring bias in our repeated game is not influenced by learning effects, although feedback is provided. Our results support the assumption that biased forecasts and their specific variance can be ascribed to anchoring effects.

Norms of cooperation and punishment differ across societies, but also within a single society. In an experiment with two subject pools sharing the same geographical and cultural origins, we show that opportunities for peer punishment increase cooperation among students but not in the general population. In previous studies, punishment magnified the differences across societies in peoples ability to cooperate. Here, punishment reversed the order: with punishment, students cooperate more than the general population while they cooperate less without it. Our results obtained with students cannot be readily generalized to the society at large.

Laboratory experiments have become a wide-spread tool in economic research. Yet, there is still doubt about how well the results from lab experiments generalize to other settings. In this paper, we investigate the self-selection process of potential subjects into the subject pool. We alter the recruitment email sent to first-year students, either mentioning the monetary reward associated with participation in experiments; or appealing to the importance of helping research; or both. We find that the sign-up rate drops by two-thirds if we do not mention monetary rewards. Appealing to subjects’ willingness to help research has no effect on signup. We then invite the so-recruited subjects to the laboratory to measure a range of preferences in incentivized experiments. We do not find any differences between the three groups. Our results show that student subjects participate in experiments foremost to earn money, and that it is therefore unlikely that this selection leads to an over-estimation of social preferences in the student population.

We introduce the give-or-destroy game that allows us to fully elicit an individual's social preference schedule. We find that about one third of the population exhibits both pro-social and anti-social preferences that are independent of payoff comparisons with those who are affected. We call this type of preference a desire to influence others. The other two thirds of the population consist to almost equal parts of payoff maximizers and pro-socials. Furthermore, we find that full information and experimenter demand may increase the extent of pro-social preferences, but neither treatment affects the extent of anti-social preferences or the distribution of social types in the population., Working papers series, ISSN 2628-1724, 2012, Heft 27

A relevance, distinctiveness and plausibility (RDP) analysis is a conceptual framework that can be used to identify when potential confounds are a problem for interpreting experimental results. We illustrate this analysis using the creation or enhancement of natural group identity by the means of priming manipulations as employed in the experiments of five target papers. Such priming manipulations may lead to experimenter demand effects and may spuriously induce behavior change. Using a RDP analysis, we show how these potential confounds are likely to be problematic for all but one of the target papers.

An ever increasing number of experiments attempts to elicit risk preferences of a population of interest with the aim of calibrating parameters used in economic models. We are concerned with two types of selection effects, which may affect the external validity of standard experiments: Sampling from a narrowly defined population of students ("experimenter-induced selection") and self-selection of participants into the experiment. We find that both types of selection lead to a sample of experts: Participants perform significantly better than the general population, in the sense of fewer violations of revealed preference conditions. Self-selection within a broad population does not seem to matter for average preferences. In contrast, sampling from a student population leads to lower estimates of average risk aversion and loss aversion parameters. Furthermore, it dramatically reduces the amount of heterogeneity in all parameters.

Anti-Muslim prejudice is widespread in Western countries. Yet, Muslims are expected to constitute a growing share of the total population in these countries over the next decades. This paper predicts that this demographic trend, other factors held constant, will increase anti-Muslim prejudice. Relying on experimental games and a formal model, we show that the generosity of rooted French toward Muslims is significantly decreased with the increase of Muslims in their midst, and demonstrate that these results are driven by the activation of rooted French taste-based discrimination against Muslims when Muslim numbers increase. Our findings call for solutions to anti-Muslim prejudice in the West.

People tend to think by analogies. We investigate whether thinking-by-analogy matters for investors’ willingness to pay for a risky asset in a laboratory experiment. We find that thinking-by-analogy has a strong influence when the assets in question have similar (but not identical) payoffs. The hypothesis of thinking-by-analogy or coarse thinking clearly outperforms other hypotheses including the hypothesis of arbitrage-free or rational pricing. When the similarity between the payoffs is reduced, the risk neutral hypothesis outperforms the hypothesis of thinking-by-analogy. Regardless of the similarity between the payoffs, the arbitrage-free or rational pricing remains the hypothesis with the worst performance.

The paper discusses opportunities to utilize the series of micro-blogs as provided by the Twitter in observation of opinion dynamics. The spontaneity of tweets is more, as the service is attached more to the mobile communications. The extraction of information in the series of tweets is demonstrated as in conceptual map and mention map. From the latter, the social network stylized properties, i.e.: power law distribution is shown. The exemplification of the methodology is on the 82nd commemoration of Indonesian Youth Pledge and the participatory movement of Indonesian capitol city, Jakarta.

Concern about potential free riding in the provision of public goods has a long history. More recently, experimental economists have turned their attention to the conditions under which free riding would be expected to occur. A model of free riding is provided here which demonstrates that existing experimental approaches fail to explore a potentially important real-world dimension of free riding. In a cash-in-advance economy, free riding becomes a two-stage problem, while existing experiments only address the second stage. That is, one would expect households with high demands for public goods relative to private goods to generate less income than households preferring ordinary private goods, because the former are unable to individually increment the public good and leisure is valuable. Existing experiments start with a given number of “tokens” for each decision-maker, effectively only addressing the second stage of the free riding problem: out of a given income under what conditions does free riding become a problem. The recommended solution to this problem is to modify experiments to allow for the generation of income prior to the decision of how to allocate that income between private and public goods. Doing so will allow a fuller understanding of the full nature of free riding behavior.

This paper shows that if a very small, exogenously given probability of terminating the exchange is introduced in an elementary investment game, more reciprocators will choose the defection strategy. Everything happens as if they “hide behind probabilities” in order to break the trust relationship. Investors do not alter their behavior in a significant way, at least not for a very small external risk. Financial assets all come with a predetermined and contractual probability that by the time when the buyer has to receive the reward for his investment, “bad luck” might have brought the asset value down to zero. In the light of the experimental findings, such trades would not provide a favorable environment for building trust.

We use a sequential prisoner's dilemma game to measure the other-regarding behavior in samples from three related populations in the upper Midwest of the United States: 100 college students, 94 non-student adults from the community surrounding the college and 1,069 adult trainee truckers in a residential training program. Both of the first two groups were recruited according to procedures commonly used in experimental economics (i.e., via e-mail and bulletin-board advertisements) and therefore subjects self-selected into the experiment. Because the structure of their training program reduced the opportunity cost of participating dramatically, 91% of the solicited trainees participated in the third group, so there was little scope for self-selection in this sample. We find no differences in the elicited other-regarding preferences between the self-selected adults and the adult trainees, suggesting that selection into this type of experiment is unlikely to bias inferences with respect to non-student adult subjects. We also test (and reject) the more specific hypothesis that approval-seeking subjects are the ones most likely to select into experiments. At the same time, we find a large difference between the self-selected students and the self-selected adults from the surrounding community: the students appear considerably less pro-social. Regression results controlling for demographic factors confirm these basic findings.

We study (anti-) coordination problems in networks in a laboratory experiment. Partici- pants interact with their neighbours in a fixed network to play a bilateral (anti-) coordination game. Our main treatment variable is the extent to which players are heterogeneous in the number of connections (neighbors) they have. Other network characteristics are held constant across treatments. We find the following results. Heterogeneity in the number of connections dramatically improves the rate of successful coordination. In addition, even though there is a multiplicity of Nash equilibria theoretically, a very sharp selection is observed empirically: the most connected player can impose her preferred Nash equilibrium almost always and observed Nash equilibria are such that all links are coordinated. As a second treatment variation we let agents decide endogenously on the amount of information they would like to have and find that local (endogenous) information is equally efficient in ensuring successful coordination as full information. We provide an intuitive explanation of these facts which is supported by our data.

Evolutionary game theory has shown that in environments characterised by a social-dilemma situation punishment may be an adaptive behaviour. Experimental evidence closely corresponds to this finding but yields contradictory results on the cooperation-enhancing effect of punishment if players are allowed to retaliate against their punishers. The present study sets out to examine the question of whether cooperation will still be part of an evolutionary stable strategy if we allow for counterpunishment opportunities in a theoretic model and tries to reconcile the seemingly contradictory findings from the laboratory. We find that the apparent contradictions can be explained by a difference in the number of retaliation stages employed (one vs. many) and even small differences in the degree of retaliativeness.

We analyse risk preferences using an experiment with real incentives in a representative sample of 1,422 Dutch respondents. Our econometric model incorporates four structural parameters that vary with observed and unobserved characteristics: Utility curvature, loss aversion, preferences towards the timing of uncertainty resolution, and the propensity to choose randomly rather than on the basis of preferences. We find that all four parameters contribute to explaining choice behaviour. The structural parameters are significantly associated with socio-economic variables, but it is essential to incorporate unobserved heterogeneity in each of them to match the rich variety of choice patterns in the data.

In auctions where bidders are uncertain of their value and are fully liable for their bids, there exists the potential for losses if bids exceed realized values. Theoretically, bids will be higher if bidders are able to mitigate this downside loss through some form of limited liability. To determine the impact of differing forms of limited liability, this paper theoretically and experimentally examines a second price auction with uncertain private values in three environments: market-based limited liability, statutory limited liability, and full liability. Market-based limited liability is induced through inter-bidder resale following the auction. Statutory limited liability is created through a default penalty option in the event that a bidder would make a loss. Bids are theoretically shown to be higher under resale and the penalty default environments than under full liability. The experimental results confirm more aggressive bidding for resale and the low penalty default treatments, but not by as much as theory predicts. Notably, under the high default penalty bidders are not bidding significantly more than under full liability, despite the theoretical prediction that they should.

There is economic pressure to postpone the retirement age, but employers are still reluctant to employ older workers. We investigate the comparative behavior of juniors and seniors in experiments conducted both onsite with the employees of two large firms and in a conventional laboratory environment with students and retirees. We show that seniors are no more risk averse than juniors and are typically more cooperative; both juniors and working seniors respond strongly to competition. The implication is that it may be beneficial to define additional incentives near the end of the career to motivate and retain older workers. (JEL C90, J14, J26, M12, M51)

Policies and explicit incentives designed for self-regarding individuals sometimes are less effective or even counterproductive when they diminish altruism, ethical norms and other social preferences. Evidence from 51 experimental studies indicates that this crowding out effect is pervasive, and that crowding in also occurs. A model in which self-regarding and social preferences may be either substitutes or complements is developed and evidence for the mechanisms underlying this non-additivity feature of preferences is provided. The result is a preference-based analogue to the Lucas Critique restricting feasible implementation to allocations that are supportable given the effect of incentives on preferences. JEL Categories: D64, H41, D78, Z13, C90

Summary We investigate attitudes toward positionality among rural farmers in Northern Ethiopia using a survey experiment. On average, we find very low positional concerns both for income per se and for income from aid projects. The results support the claim that positional concerns are positively correlated with absolute level of income. The implications of our results on implementation of aid projects are discussed.

We combine data from a risk preference elicitation experiment conducted on a representative sample via the Internet with laboratory data on students for the same experiment to investigate effects of implementation mode and of subject pool selection. We find that the frequency of errors in the lab experiment is drastically below that of the representative sample in the Internet experiment, and average risk aversion is also lower. Considering the student-like subsample of the Internet subjects and comparing a traditional lab design with an Internet-like design in the lab gives two ways to decompose these differences into differences due to subject pool selection and differences due to implementation mode. Both lead to the conclusion that the differences are due to selection and not implementation mode. An analysis of the various steps leading to participation or non-participation in the Internet survey leads shows that these processes are selective in selecting subjects who make fewer errors, but do not lead to biased conclusions on risk preferences. These findings point at the usefulness of the Internet survey as an alternative to a student pool in the laboratory if the ambition is to use the experiments to draw inference on a broad population.

Systemic risk is a key concern for central banks charged with safeguarding overall financial stability. In this paper we investigate how systemic risk is affected by the structure of the financial system. We construct banking systems that are composed of a number of banks that are connected by interbank linkages. We then vary the key parameters that define the structure of the financial system - including its level of capitalisation, the degree to which banks are connected, the size of interbank exposures and the degree of concentration of the system - and analyse the influence of these parameters on the likelihood of contagious (knock-on) defaults. First, we find that the better capitalised banks are, the more resilient is the banking system against contagious defaults and this effect is non-linear. Second, the effect of the degree of connectivity is non-monotonic, that is, initially a small increase in connectivity increases the contagion effect; but after a certain threshold value, connectivity improves the ability of a banking system to absorb shocks. Third, the size of interbank liabilities tends to increase the risk of knock-on default, even if banks hold capital against such exposures. Fourth, more concentrated banking systems are shown to be prone to larger systemic risk, all else equal. In an extension to the main analysis we study how liquidity effects interact with banking structure to produce a greater chance of systemic breakdown. We finally consider how the risk of contagion might depend on the degree of asymmetry (tiering) inherent in the structure of the banking system. A number of our results have important implications for public policy, which this paper also draws out.

We experimentally examine the effects of flexible and fixed prices in markets for experience goods in which demand is driven by trust. With flexible prices, we observe low prices and high quality in competitive (oligopolistic) markets, and high prices coupled with low quality in non-competitive (monopolistic) markets. We then introduce a regulated intermediate price above the oligopoly price and below the monopoly price. The effect in monopolies is more or less in line with standard intuition. As price falls volume increases and so does quality, such that overall efficiency is raised by 50%. However, quite in contrast to standard intuition, we also observe an efficiency rise in response to regulation in oligopolies. Both, transaction volume and traded quality are, in fact, maximal in regulated oligopolies.