We experimentally investigate to what extent people trust and honor trust when they are playing with other people’s money (OPM). We adopt the well-known trust game by Berg et al. (in Games Econ. Behav. 10:122–142, 1995), with the difference that the trustor (sender) who sends money to the trustee (receiver) does this on behalf of a third party. We find that senders who make decisions on behalf of others do not behave significantly different from senders in our baseline trust game who manage their own money. But receivers return significantly less money when senders send a third party’s money. As a result, trust is only profitable in the baseline trust game, but not in the OPM treatment. The treatment effect among the receivers is gender specific. Women return significantly less money in OPM than in baseline, while there is no such treatment effect among men. Moreover, women return significantly less than men in the OPM treatment.

Favor trading is common. We do something nice for someone and they do something nice in return. Several motives might underlie such behavior, including altruism, strategic motives, and direct or indirect positive reciprocity. It is not yet well-understood how these fit together to affect behavior, how they interact in various institutional structures, and how they play out over time. We use a laboratory experiment to study the elements and dynamics of favor trading in a particular setting: the private provision of a public good. In our experiment, giving subjects the ability to practice targeted reciprocity by making a simple, low-cost change in information provision increases contributions to the public good by 14 %. Subjects reward group members who have previously been generous to them and withhold rewards from ungenerous group members. Strategic concerns cannot explain all of this behavior, and it must be at least partly due to direct reciprocity. When someone cannot directly benefit from favor trading, he gives much less to the public good. People thus excluded from the “circle of reciprocity” provide a clean and strict test of indirect reciprocity. Contrary to previous studies in the literature, we do not observe indirect reciprocity.

In many auctions the valuation structure involves both private and common value elements. Existing experimental evidence (e.g. Goeree and Offerman in Am. Econ. Rev. 92(3):625–643, 2002) demonstrates that first-price auctions with this valuation structure tend to be inefficient, and inexperienced subjects tend to bid above the break-even bidding threshold. In this paper, we compare first-price auctions with an alternative auction mechanism: the least-revenue auction. This auction mechanism shifts the risk regarding the common value of the good to the auctioneer. Such a shift is desirable when ex post negative payoffs for the winning bidder results in unfulfilled contracts, as is often the case in infrastructure concessions contracts. We directly compare these two auction formats within two valuation structures: (1) pure common value and (2) common value with a private cost. We find that, relative to first-price auctions, bidding above the break-even bidding threshold is significantly less prevalent in least-revenue auctions regardless of valuation structure. As a result, revenue in first-price auctions is higher than in least-revenue auctions, contrary to theory. Further, when there are private and common value components, least-revenue auctions are significantly more efficient than first-price auctions.

A vast amount of empirical and theoretical research on public good games indicates that the threat of punishment can curb free-riding in human groups engaged in joint enterprises. Since punishment is often costly, however, this raises an issue of second-order free-riding: indeed, the sanctioning system itself is a common good which can be exploited. Most investigations, so far, considered peer punishment: players could impose fines on those who exploited them, at a cost to themselves. Only a minority considered so-called pool punishment. In this scenario, players contribute to a punishment pool before engaging in the joint enterprise, and without knowing who the free-riders will be. Theoretical investigations (Sigmund et al., Nature 466:861–863, 2010) have shown that peer punishment is more efficient, but pool punishment more stable. Social learning, i.e., the preferential imitation of successful strategies, should lead to pool punishment if sanctions are also imposed on second-order free-riders, but to peer punishment if they are not. Here we describe an economic experiment (the Mutual Aid game) which tests this prediction. We find that pool punishment only emerges if second-order free riders are punished, but that peer punishment is more stable than expected. Basically, our experiment shows that social learning can lead to a spontaneously emerging social contract, based on a sanctioning institution to overcome the free rider problem.

This paper reports results of a natural field experiment on the dictator game where subjects are unaware that they are participating in an experiment. Three other experiments explore, step by step, how laboratory behavior of students relates to field behavior of a general population. In all experiments, subjects display an equally high amount of pro-social behavior, whether they are students or not, participate in a laboratory or not, or are aware of their participating in an experiment or not. This paper shows that there are settings where laboratory behavior of students is predictive for field behavior of a general population.

This study considers a model of road congestion with average cost pricing. Subjects must choose between two routes—Road and Metro. The travel cost on the road is increasing in the number of commuters who choose this route, while the travel cost on the metro is decreasing in the number of its users. We examine how changes to the road capacity, the number of commuters, and the metro pricing scheme influence the commuters’ route-choice behavior. According to the Downs-Thomson paradox, improved road capacity increases travel times along both routes because it attracts more users to the road and away from the metro, thereby worsening both services. A change in route design generates two Nash equilibria; and the resulting coordination problem is amplified even further when the number of commuters is large. We find that, similar to other binary choice experiments with congestion effects, aggregate traffic flows are close to the equilibrium levels, but systematic individual differences persist over time.

This paper introduces new experimental designs to examine how conditional cooperation and punishment behaviours respond to the full range of variation in the contributions of others. It is shown that contributions become significantly more selfish-biased as others contribute more unequally, while punishment increases both with decreasing contributions by the target player and increasing contributions by a third player. Low contributors who punish antisocially do not direct their punishment specifically toward high contributors, while their beliefs indicate that they expect to themselves be punished.

ConG is software for conducting economic experiments in continuous and discrete time. It allows experimenters with limited programming experience to create a variety of strategic environments featuring rich visual feedback in continuous time and over continuous action spaces, as well as in discrete time or over discrete action spaces. Simple, easily edited input files give the experimenter considerable flexibility in specifying the strategic environment and visual feedback. Source code is modular and allows researchers with programming skills to create novel strategic environments and displays.

We look at gender differences among adolescents in Sweden in preferences for competition, altruism and risk. For competitiveness, we explore two different tasks that differ in associated stereotypes. We find no gender difference in competitiveness when comparing performance under competition to that without competition. We further find that boys and girls are equally likely to self-select into competition in a verbal task, but that boys are significantly more likely to choose to compete in a mathematical task. This gender gap diminishes and becomes non-significant when we control for actual performance, beliefs about relative performance, and risk preferences, or for beliefs only. Girls are also more altruistic and less risk taking than boys.

We study price efficiency and trading behavior in laboratory limit order markets with asymmetrically informed traders. Markets differ in the number of insiders present and in the subset of traders who receive information about the number of insiders present. We observe that price efficiency (i) is the higher the higher the number of insiders in the market but (ii) is unaffected by changes in the subset of traders who know about the number of insiders present. (iii) Independent of the number of insiders, price efficiency increases gradually over time. (iv) The insiders’ information is reflected in prices via limit (market) orders if the asset’s value is inside (outside) the bid-ask spread. (v) In situations where limit and market orders yield positive profits, insiders clearly prefer market orders, indicating a strong desire for immediate transactions.

Most common pool resource (CPR) dilemmas share two features: they evolve over time and they are managed under environmental uncertainties. We propose a stylized dynamic model that integrates these two dimensions. A distinguishing feature of our model is that the duration of the game is determined endogenously by the users’ collective decisions. In the proposed model, if the resource stock level below which the irreversible event occurs is known in advance, then the optimal resource use coincides with a unique symmetric equilibrium that guarantees survival of the resource. As the uncertainty about the threshold level increases, resource use increases if users adopt decision strategies that quickly deplete the resource stock, but decreases if they adopt path strategies guaranteeing that the unknown threshold level is never exceeded. We show that under relatively high uncertainty about resource size, CPR users frequently implement decision strategies that terminate the game immediately. When this uncertainty is reduced, they maintain a positive resource level for longer durations.

We show that, if giving is equivalent to not taking, impure altruism could account for List’s (in Journal of Political Economy 115(3):482–493, 2007) finding that the payoff to recipients in a dictator game decreases when the dictator has the option to take. We examine behavior in dictator games with different taking options but equivalent final payoff possibilities. We find that recipients tend to earn more as the amount the dictator must take to achieve a given final payoff increases, a result consistent with the hypothesis that the cold prickle of taking is stronger than the warm glow of giving. We conclude that not taking is not equivalent to giving and agree with List (in Journal of Political Economy 115(3):482–493, 2007) that the current social preference models fail to rationalize the observed data.

We experimentally investigate the impact of recognizing contributors on public good contributions. We vary recognizing all, highest or lowest contributors. Consistent with previous studies, recognizing all contributors significantly increases contributions relative to the baseline. Recognizing only the highest contributors does not increase contributions compared to not recognizing contributors, while recognizing only the lowest contributors is as effective as recognizing all contributors. These findings support our conjecture that aversion from shame is a more powerful motivator for giving than anticipation of prestige.

We examine elicitation effects in a multi-stage bargaining experiment with escalating stakes conducted under direct-response and strategy-method elicitation. We find a significantly greater incidence of decisions leading to bargaining failure under direct responses. In addition, the predictive power of alternative risk attitude measures differs between the elicitation methods. Potential sources of the effects and resulting implications are discussed.

We conduct a laboratory experiment to explore whether the protection of intellectual property (IP) incentivizes people to create non-rivalrous knowledge goods, foregoing the production of other rivalrous goods. In the contrasting treatment with no IP protection, participants are free to resell and remake non-rivalrous knowledge goods originally created by others. We find that creators reap substantial profits when IP is protected and that rampant pirating is common when there is no IP protection, but IP protection in and of itself is neither necessary nor sufficient for generating wealth from the discovery of knowledge goods. Rather, individual entrepreneurship is the key.

We examine in the laboratory how having the opportunity to donate to a charity in the future affects the likelihood of engaging in dishonest behavior in the present. We also examine how charitable donations are affected by past ethical choices. First, subjects self-report their performance on a task, which provides them with an opportunity for undetected cheating. In the second stage they can donate some of the money earned in the first stage to a charity. Only subjects in the treatment group know about the opportunity to donate in the second stage. We find that more subjects cheat if they know they can donate some of the money to charity. We also find that subjects in treatment end up donating less to charity and that both honest and dishonest subjects donate less in treatment. We propose a new hypothesis that explains these results: past violations of social norms numb one’s conscience, leading to more antisocial behavior.