The analysis of data from experiments in economics routinely involves testing multiple null hypotheses simultaneously. These different null hypotheses arise naturally in this setting for at least three different reasons: when there are multiple outcomes of interest and it is desired to determine on which of these outcomes a treatment has an effect; when the effect of a treatment may be heterogeneous in that it varies across subgroups defined by observed characteristics and it is desired to determine for which of these subgroups a treatment has an effect; and finally when there are multiple treatments of interest and it is desired to determine which treatments have an effect relative to either the control or relative to each of the other treatments. In this paper, we provide a bootstrap-based procedure for testing these null hypotheses simultaneously using experimental data in which simple random sampling is used to assign treatment status to units. Using the general results in Romano and Wolf (Ann Stat 38:598–633, 2010), we show under weak assumptions that our procedure (1) asymptotically controls the familywise error rate—the probability of one or more false rejections—and (2) is asymptotically balanced in that the marginal probability of rejecting any true null hypothesis is approximately equal in large samples. Importantly, by incorporating information about dependence ignored in classical multiple testing procedures, such as the Bonferroni and Holm corrections, our procedure has much greater ability to detect truly false null hypotheses. In the presence of multiple treatments, we additionally show how to exploit logical restrictions across null hypotheses to further improve power. We illustrate our methodology by revisiting the study by Karlan and List (Am Econ Rev 97(5):1774–1793, 2007) of why people give to charitable causes.

Individuals have opportunities to behave pro-socially at different points in time. This study investigates the interdependence between temporarily separated good deeds and their effect on individual pro-social behavior. In a multi-session laboratory experiment, subjects play a donation dictator game. The first group of subjects runs through two sessions on the same day. For the second group, there is a time-lag of one week between sessions. In both treatments, subjects decrease their donation decision in the second session. Spillover effects of pro-social behavior, however, decrease over time as the reduction in donations is smaller for subjects with larger time-lag between decisions.

Many social dilemmas involve deciding among alternative public goods, and include cases where part of the population may dislike a particular option. In such cases, an agent may want to spend resources to oppose or reduce the provision of the option they don’t like. We propose the generalized voluntary contributions mechanism (GVCM), which allows allocating resources to increase or decrease the level of public good. Our main treatment variables include two versions of the GVCM (uncensored, or censored at positive provision). We study performance of GVCM for various compositions of the polarized preferences. We find that uncensoring the mechanism does not impose net efficiency costs and leads to more diversity in the provision of the public good. The nature of efficiency loss is more complex compared to standard VCM and is not driven by free riding.

We use a within-subjects design to study how responsibility for the payoffs of different number of others influences the choices under risk, and how choosing together with another person changes these decisions. After controlling for the regression to the mean, we find a weak effect of responsibility for one other person on risk taking as compared to choosing just for oneself. We, however, do find that the number of others influenced by the choice matters: when it increases from one to three, risk averse subjects choose riskier options and risk loving subjects choose more cautiously, which pushes the choices towards the modal risk preferences in the population. Mutual responsibility makes choices for others shift even more in the same direction. The observed behavior is in accordance with the blame avoidance hypothesis: decision makers with responsibility try to reduce the amount of blame for their choices, which is minimal when the choices for others are consistent with what they would have chosen for themselves.

Evidence from response time studies and time pressure experiments has led several authors to conclude that “fairness is intuitive”. In light of conflicting findings, we provide theoretical arguments showing under which conditions an increase in “fairness” due to time pressure indeed provides unambiguous evidence in favor of the “fairness is intuitive” hypothesis. Drawing on recent applications of the Drift Diffusion Model (Krajbich et al. in Nat Commun 6:7455, 2015a), we demonstrate how the subjective difficulty of making a choice affects decisions under time pressure and time delay, thereby making an unambiguous interpretation of time pressure effects contingent on the choice situation. To explore our theoretical considerations and to retest the “fairness is intuitive” hypothesis, we analyze choices in two-person binary dictator and prisoner’s dilemma games under time pressure or time delay. In addition, we manipulate the subjective difficulty of choosing the fair relative to the selfish option. Our main finding is that time pressure does not consistently promote fairness in situations where this would be predicted after accounting for choice difficulty. Hence, our results cast doubt on the hypothesis that “fairness is intuitive”.

While economists recognize the important role of formal institutions in the promotion of trade, there is increasing agreement that institutions are typically endogenous to culture, making it difficult to disentangle their separate contributions. Lab experiments that assign institutions exogenously and measure and control individual cultural characteristics can allow for clean identification of the effects of institutions, conditional on culture, and help us understand the relationship between behavior and culture, under a given institutional framework. We focus on cultural tendencies toward individualism/collectivism, which social psychologists highlight as an important determinant of many behavioral differences across groups and people. We design an experiment to explore the relationship between subjects’ degree of individualism/collectivism and their willingness to abandon a repeated, bilateral exchange relationship in order to seek potentially more lucrative trade with a stranger, under enforcement institutions of varying strength. Overall, we find that individualists tend to seek out trade more often than collectivists. A diagnostic treatment and additional analysis suggests that this difference may reflect both differential altruism/favoritism to in-group members and different reactions to having been cheated in the past. This difference is mitigated somewhat as the effectiveness of enforcement institutions increases. Nevertheless we see that cultural dispositions are associated with willingness to seek out trade, regardless of institutional environment.

We conduct a series of experiments to examine the effects of the make and take fee structure currently used by equity exchanges in the U.S. We examine the effects of these fees on measures of market quality (efficiency, book depth, and the bid-ask spread). We find spreads to be smaller in the presence of make and take fees, and we note that this fee structure seems to induce buyers (moreso than sellers) to compete for rebates from the exchange leading to higher prices and lower profits. To test whether our results are due to the make and take fee structure or are artefacts of trading fees in general, we performed a second set of experiments in which traders on both sides of a transaction were assessed an identical fee. These identical trading fees do not appear to significantly affect our market quality measures.

Sequential multi-battle contests are predicted to induce lower expenditure than simultaneous contests. This prediction is a result of a “New Hampshire Effect”—a strategic advantage created by the winner of the first battle. Although our laboratory study provides evidence for the New Hampshire Effect, we find that sequential contests generate significantly higher (not lower) expenditure than simultaneous contests. This is mainly because in sequential contests, there is significant over-expenditure in all battles. We suggest sunk cost fallacy and utility of winning as two complementary explanations for this behavior and provide supporting evidence.

We study how the scope of negative externalities from market activity affects the willingness of market actors to exhibit social responsibility. Using the laboratory experimental paradigm introduced by Bartling et al. (Q J Econ 130(1):219–266, 2015), we compare the voluntary internalization of negative social impacts by market actors in cases where the negative externality is diffused among many subjects or is concentrated on a single subject. We (1) replicate earlier results demonstrating substantial degrees of market social responsibility and (2) find that the willingness of market actors to act pro-socially is only slightly affected by whether the impacts are concentrated or diffused.

Decisions to trust in strategic situations involve ambiguity (unknown probabilities). Despite many theoretical studies on ambiguity in game theory, empirical studies have lagged behind due to a lack of measurement methods, where separating ambiguity attitudes from beliefs is crucial. Baillon et al. (Econometrica, 2018b) introduced a method that allows for such a separation for individual choice. We extend this method to strategic situations and apply it to the trust game, providing new insights. People’s ambiguity attitudes and beliefs both matter for their trust decisions. People who are more ambiguity averse decide to trust less, and people with more optimistic beliefs about others’ trustworthiness decide to trust more. However, people who are more a-insensitive (insufficient discrimination between different likelihood levels) are less likely to act upon their beliefs. Our measurement of beliefs, free from contamination by ambiguity attitudes, shows that traditional introspective trust survey measures capture trust in the commonly accepted sense of belief in trustworthiness of others. Further, trustworthy people also decide to trust more due to their beliefs that others are similar to themselves. This paper shows that applications of ambiguity theories to game theory can bring useful new empirical insights.

Communication has been shown to increase proposer power in multilateral bargaining settings that use majority voting rule via competition between non-proposers for a place in the coalition. In this paper we investigate whether communication affects bargaining outcomes and the bargaining process in settings in which the competition effect is not present. We study committees that use unanimity rule to pass allocations. We find that in these settings, communication has the complete opposite effect compared with the majority settings: under unanimity, communication eliminates the inefficiencies that are present in settings without communication and it shifts bargaining outcomes towards egalitarian allocations with no proposer power. Communication logs provide insights regarding the topics subjects discuss and communication content correlates with bargaining outcomes.

With a novel experimental design we investigate whether risk perception, return expectations, and investment propensity are influenced by the scale of the vertical axis in charts. We explore this for two presentation formats, namely return charts and price charts, where we depict low- and high-volatility assets with distinct trends. We find that varying the scale strongly affects people’s risk perception, as a narrower scale of the vertical axis leads to significantly higher perceived riskiness of an asset even if the underlying volatility is the same. Furthermore, past returns predict future return expectations almost perfectly. In our setting perceived profitability was considered more important than perceived riskiness when making investment choices. Overall we show that adapting the scale of a chart makes it easier to recognize yearly return variations within a single security, but at the same time makes it harder to identify differences between dissimilar securities. This is something regulators should be aware of and take into account in the rules they set.

Studies of experimental and betting markets have shown that markets are able to efficiently aggregate information dispersed over many traders. We study information aggregation in Arrow–Debreu markets using a novel information structure. Compared to previous studies, the information structure is more complex, allows for heterogeneity in information among traders—which provides insights into the way in which information is gradually disseminated in the market—and generates situations in which all traders hold identical beliefs over the traded assets’ values, thus providing a harsh stress test for belief updating. We find little evidence for information aggregation and dissemination in early rounds. Nonetheless, after traders gain experience with the market mechanism and structure, prices converge to reveal the true state of the world. Elicited post-market beliefs reveal that markets are able to efficiently aggregate dispersed information even if individual traders remain uninformed, consistent with the marginal trader hypothesis.

This paper studies whether and how strategy revision opportunities affect levels of collusion in indefinitely repeated two-player games. Consistent with standard theory, we find that such opportunities do not affect strategy choices, or collusion levels, if the game is of strategic substitutes. In games of strategic complements, by contrast, revision opportunities lead to more collusion. We discuss alternative explanations for this result.

Bayesian updating remains the benchmark for dynamic modeling under uncertainty within economics. Recent theory and evidence suggest individuals may process information asymmetrically when it relates to personal characteristics or future life outcomes, with good news receiving more weight than bad news. I examine information processing across a broad set of contexts: (1) ego relevant, (2) financially relevant, and (3) non value relevant. In the first two cases, information about outcomes is valenced, containing either good or bad news. In the third case, information is value neutral. In contrast to a number of previous studies I do not find differences in belief updating across valenced and value neutral settings. Updating across all contexts is asymmetric and conservative: the former is influenced by sequences of signals received, a new variation of confirmation bias, while the latter is driven by non-updates. Despite this, posteriors are well approximated by those calculated using Bayes’ rule. Most importantly these patterns are present across all contexts, cautioning against the interpretation of asymmetric updating or other deviations from Bayes’ rule as being motivated by psychological biases.

We examine the interplay between unethical behaviour and competition with a lab experiment. Subjects play the role of firms in monopoly, weak competition (Bertrand–Edgeworth duopoly) or strong competition (Bertrand duopoly). Costs are determined either by a computer draw or a self-reported die roll, and pricing decisions are made with knowledge of one’s own costs and—in duopoly—the rival firm’s costs. Under self-reporting, lying is profitable and undetectable except statistically. We find that competition and lying are mutually reinforcing. We observe strong evidence that (behavioural) competition in both duopoly treatments is more intense when lying is possible: prices are significantly lower than when lying is impossible, even controlling for differences in costs. We also observe more lying under duopoly than monopoly—despite the greater monetary incentives to lie in the monopoly case—though these differences are not always significant.

A rich history of theoretical models in finance shows that speculation can lead to overpricing and price bubbles. We provide evidence that, indeed, individual speculative behavior fuels overpricing in (experimental) asset markets. In a first step, we elicit individual speculative behavior in a one-shot setting with a novel speculation elicitation task (SET). In a second step, we use this measure of speculative behavior to compose dynamic, continuous double auction markets in line with Smith et al. (Econometrica 56(5):1119–1151, 1988). We find significant higher overpricing in markets with traders who exhibited more speculative behavior in the individual SET. However, we find no such differences in overpricing when we test for alternative explanations, using a market environment introduced by Lei, Noussair, and Plott (Econometrica 69(4):831–859, 2001) where speculation is impossible. Taken together, our results corroborate the notion that speculation is an important factor in overpricing and bubble formation if market environments allow for the pursuit of capital gains.

We explore the efficiency and distributive implications of a multilateral bargaining model with endogenous production of the surplus under two different timings: ex ante and ex post bargaining. Both timings are commonly observed in business partnerships and alliance formations. The theoretical predictions confirm an intuitive economic tenet: in ex post bargaining, effort is considered sunk and opportunistic bargaining behavior will dissuade players from producing. On the other hand, ex ante bargaining entails an allocation of ownership shares that induces at least certain members to invest in the common fund because their return is guaranteed. Experiments show opposite results: ex post bargaining yields almost fully efficient outcomes while the reverse timing entails near zero efficiency. The psychological theory of inequity is useful in reconciling these divergent results.