We study the interaction of the effects of the strategic environment and communication on the observed levels of cooperation in two-person finitely repeated games with a Pareto-inefficient Nash equilibrium and replicate previous findings that point to higher levels of tacit cooperation under strategic complementarity than under strategic substitutability. We find that this is not because of differences in the levels of reciprocity as previously suggested. Instead, we demonstrate that slow learning coupled with noisy choices may drive this effect. When subjects are allowed to communicate in free-form online chats before making choices, cooperation levels increase significantly to the extent that the difference between strategic complements and substitutes disappears. A machine-assisted natural language processing approach then shows how the content of communication is dependent on the strategic environment and cooperative behavior, and indicates that subjects in complementarity games reach full cooperation by agreeing on gradual moves toward it.

We propose a novel approach to check whether individual behaviour in binary-choice participation games is consistent with the restrictions imposed by symmetric models. This approach allows in particular an assessment of how much cluster-heterogeneity a symmetric model can tolerate to remain consistent with its behavioural restrictions. We assess our approach with data from market-entry experiments which we analyse through the lens of ‘Exploration versus Exploration’ (EvE, which is equivalent to Logit-QRE) or of Impulse Balance Equilibrium (IBE). We find that when the symmetry assumption is imposed, both models are typically rejected when assuming pooled data and IBE yields more data-consistent estimates than EvE, i.e., IBE’s estimates of session and pooled data are more consistent than those of EvE. When relaxing symmetry, EvE (IBE) is rejected for 17% (42%) of the time. Although both models support cluster-heterogeneity, IBE is much less likely to yield over-parametrised specifications and insignificant estimates so it outperforms EvE in accommodating a model-consistent cluster-heterogeneity. The use of regularisation procedures in the estimations partially addresses EvE’s shortcomings but leaves our overall conclusions unchanged.

Transfers of resources in dictator games vary significantly by the characteristics of recipients. We focus on social norms and demonstrate that variation in the recipient changes both giving and injunctive norms and may offer an explanation for differences in giving. We elicit generosity using dictator games, and social norms using incentivized coordination games, with two different recipient types: an anonymous student and a charitable organization. A within-subjects design ensures that other factors are held constant. Our results show that differences in giving behavior are closely related to differences in social norms of giving across contexts. Controlling for individual differences in beliefs about the norm, subjects do not weight compliance with the norms in the student recipient or charity recipient dictator game differently. These results suggest that the impact of context on giving co-occurs with an impact on social norms.

Many models of investor behavior predict that investors prefer assets that they believe to have positively skewed return distributions. We elicit detailed return expectations for a broad index fund and a single stock in a representative sample of the Dutch population. The data show substantial heterogeneity in individuals’ skewness expectations of which only very little is captured by sociodemographics. Across assets, most respondents expect a higher variance and skewness for the individual stock compared to the index fund. Portfolio allocations increase with the skewness of respondents’ return expectations for the respective asset, controlling for other moments of a respondent’s expectations.

We design an experiment to study how reversible entry decisions are affected by public and private payoff disclosure policies. In our environment, subjects choose between a risky payoff, which evolves according to an autoregressive process, and a constant payoff. The treatments vary the information disclosure rule on the risky payoff, such that in the public information treatment the risky payoff is always observable, while in the private information treatment, the risky payoff is observable only to the participants who enter the market. We find that under private information, market entry is higher, which suggests that subjects engage in exploration and place value on information.

It is now well established that higher-order risk preferences play a crucial role in determining the risky choices of decision makers in a wide range of important areas such as economics, finance and health. While influential theories of risky choice in those fields can explain attitudes to second order risk, the implications of these models for higher order risk preferences is still to be developed. This paper addresses that gap for the Markowitz (J Political Econ, 60:151–58, 1952) (M) model of utility which embodies reference-dependent utility, loss aversion and was seemingly the first model to explain the fourfold attitude to risk. In this paper, we set out new properties of the M model for higher order preferences, such as higher-order risky choice reversals, that can help explain experimental evidence not readily reconcilable with other models of risky choice. A second contribution of the paper is to empirically examine the heterogeneity of preference functionals describing second as well as higher order risky choices using hierarchical Bayesian estimation methods. Our analysis of the risky choices revealed in three prominent studies provides support for the M model as a useful complement to other leading models of risky choice such as cumulative prospect theory (CPT). In addition, we set up a new experiment whose design is shown to have satisfactory discriminatory power between the M and CPT specifications, and our results based on the Bayes factor confirm the heterogeneity of preference functionals across decision makers, and that the CPT specification is more prevalent.

Does loss aversion apply to social image concerns? In a laboratory experiment, we first induce social image in a relevant domain, intelligence, through public ranking. In a second stage, subjects experience a change in rank and are offered scope for lying to improve their final, also publicly reported rank. Subjects who care about social image and experience a decline in rank lie more than those experiencing gains. Moreover, we document a discontinuity in lying behavior when moving from rank losses to gains. Our results are in line with loss aversion in social image concerns.

An important issue for many economic experiments is how the experimenter can ensure sufficient power in order to reject one or more hypotheses. The paper illustrates how methods for testing multiple hypotheses simultaneously in adaptive, two-stage designs can be used to improve the power of economic experiments. We provide a concise overview of the relevant theory and illustrate the method in three different applications. These include a simulation study of a hypothetical experimental design, as well as illustrations using two data sets from previous experiments. The simulation results highlight the potential for sample size reductions, maintaining the power to reject at least one hypothesis while ensuring strong control of the overall Type I error probability.

A laboratory study was carried out to analyze the relationship between ambiguity regarding the sharing norms in structured alternating-offer bargaining and gender differences in bargaining. Symmetric environments, where a 50:50 split emerges as the unique sensible norm, showed the lowest ambiguity and gender differences are absent. We increased ambiguity by introducing asymmetries into the bargaining environment by making one bargaining party get a higher share than the other (due to empowerment, entitlement or informational asymmetries), but without imposing new sharing norms. In these situations, men are less likely to reach an agreement, but, when they do, they obtain a larger share of the pie. As a result, men and women show similar overall earnings but earnings are lower when bargaining with men. We find suggestive evidence that gender differences diminish when we reduce ambiguity regarding the sharing norms by providing information about other participants’ agreements in asymmetric environments.

The experimental literature on individual choice has repeatedly documented how seemingly-irrelevant options systematically shift decision-makers’ choices. However, little is known about such effects in strategic interactions. We experimentally examine whether adding seemingly-irrelevant strategies, such as a dominated strategy or a duplicate of an existing strategy, affects players’ behavior in simultaneous games. In coordination games, we find that adding a dominated strategy increases the likelihood that players choose the strategy which dominates it, and duplicating a strategy increases its choice share; The players’ opponents seem to internalize this behavior and best respond to it. In single-equilibrium games, these effects disappear. Consequently, we suggest that irrelevant strategies affect behavior only when they serve a strategic purpose. We discuss different theoretical approaches that accommodate the effect of salience and may explain our findings.

Expectations of future returns are pivotal for investors’ trading decisions, and are therefore an important determinant of the evolution of actual returns. Evidence from individual choice experiments with exogenously given time series of returns suggests that subjects’ return forecasts are substantially affected by how they are elicited and by the format in which subjects receive information about past asset performance. In order to understand the impact of these effects found at the individual level on market dynamics, we consider a learning to forecast experiment where prices and returns are endogenously determined and depend directly upon subjects’ forecasts. We vary both the variable (prices or returns) subjects observe and the variable (prices or returns) they have to forecast, with the same underlying data generating process for each treatment. Although there is no significant effect of the presentation format of past information, we do find that markets are significantly more unstable when subjects have to forecast returns instead of prices. Our results therefore show that the elicitation format may exacerbate, or even create, bubbles and crashes in financial markets.

International economic theory suggests that people should embrace economic integration because it promises large gains. But policy reversals such as Brexit indicate a desire for economic disintegration. Here we report results of an experiment of how size and cross-country distribution of gains from integration influence individuals’ inclination to cooperate to reap its intended benefits and to embrace or reject integration. The design considers an indefinitely repeated helping game with multiple equilibria and strategic uncertainty. The data reveal that inequality of potential gains neither affected behavior nor reduced support for economic integration. However, integration may lead to disappointing, unequally distributed welfare gains, undermining support for the policy. This suggests that to better assess integration policies, we should account for the spillover effects of integration on behavior. Miscalculating this behavioral aspect may undermine the intended development goals and motivate calls for dramatic policy-reversals.

As informational leakages become a common occurrence in economic and business settings, the impact of observability on behavior in adversarial situations assumes increased importance. Consider a two-player contest where there is a probabilistic information leak about one player’s action and the recipient of the information has the ability to revise his contest expenditure in response to the leaked rival choice. How does the ability to revise and resubmit affect each contestant’s behavior? We design a laboratory experiment to study this question for two well-known contest games: the lottery contest and the all-pay auction. Equilibrium predicts that compared to simultaneous moves, the strategic asymmetry arising from the ability to revise has no effect on expected expenditure in the lottery contest. In contrast, in the all-pay auction expected expenditure is decreasing in the probability of informational leakage. Experimental data support these predictions despite overexpenditure relative to equilibrium. Furthermore, the potential observability of the rival’s action confers an advantage on the informed player not only in the all-pay auction, as theory predicts, but also in the lottery contest if the probability of leakage is high.

Do principals' distributive preferences affect the allocation of incentives within firms? We run a Principal-Agent lab experiment, framed as a firm setting. In the experiment, subjects are randomized in the principal or worker position. Principals must choose piece rate wage contracts for two workers that differ in terms of ability. Workers have to choose an effort level that is non-contractible. Principals are either paid in proportion to the output produced (Stakeholder treatment) or paid a fixed wage (Spectator treatment). We study how principals make trade-offs between incentive concerns (motivating workers to maximize output) and their own normative distributive preferences. We find that, despite the firm-frame and the moral hazard situation, principals do hold egalitarian concerns, as principals are on average willing to trade off their firm's performance (and so their own income) for more wage equality among their workers. The willingness to reduce inequality among workers is sensitive to both extensive and intensive margin incentives, which shows that principals' choices are shaped by incentives that they face themselves.

Ostracism, or exclusion by peers, has been practiced since ancient times as a severe form of punishment against transgressors of laws or social norms. The purpose of this paper is to offer a comprehensive analysis on how ostracism affects behavior and the functioning of a social group. We present data from a laboratory experiment, in which participants face a social dilemma on how to allocate limited resources between a productive activity and theft, and are given the opportunity to exclude members of their group by means of majority voting. Our main treatment features an environment with heterogeneity in productivity within groups, thus creating inequalities in economic opportunities and income. We find that exclusion is an effective form of punishment and decreases theft by excluded members once they are re-admitted into the group. However, it also leads to some retaliation by low-productivity members. A particularly worrisome aspect of exclusion is that punished group members are stigmatized and have a higher probability of facing exclusion again. We discuss implications of our findings for penal systems and their capacity to rehabilitate prisoners.

We study distributional preferences in adolescent peer networks. Using incentivized choices between allocations for themselves and a passive agent, children are classified into efficiency-loving, inequality-loving, inequality-averse, and spiteful types. We find that pairs of students who report a friendship link are more likely to exhibit the same preference type than other students who attend the same school. The relation between types is almost completely driven by inequality-loving and spiteful types. The role of peer networks in explaining distributional preferences goes beyond network composition effects. A low rank in academic performance and a central position within the network relate positively to a higher likelihood of being classified as spiteful. Hence, social hierarchies seem to be correlated with distributional preference types.

We provide a generalized revealed preference test for quasilinear preferences. The test applies to nonlinear budget sets and non-convex preferences as those found in taxation and nonlinear pricing contexts. We study the prevalence of quasilinear preferences in a laboratory real-effort task experiment with nonlinear wages. The experiment demonstrates the empirical relevance of our test. We find support for either convex (non-separable) preferences or quasilinear preferences but weak support for the hypothesis of both quasilinear and convex preferences.

We conduct a laboratory experiment among male participants to investigate whether rewarding schemes that depend on work performance—in particular, tournament incentives—induce more stress than schemes that are independent of performance—fixed payment scheme. Stress is measured over the entire course of the experiment at both the hormonal and psychological level. Hormonal stress responses are captured by measuring salivary cortisol levels. Psychological stress responses are measured by self-reported feelings of stress and primary appraisals. We find that tournament incentives induce a stress response whereas a fixed payment does not induce stress. This stress response does not differ significantly across situations in which winners and losers of the tournament are publically announced and situations in which this information remains private. Biological and psychological stress measures are positively correlated, i.e. increased levels of cortisol are associated with stronger feelings of stress. Nevertheless, neither perceived psychological stress nor elevated cortisol levels in a previous tournament predict a subsequent choice between tournaments and fixed payment schemes, indicating that stress induced by incentives schemes is not a relevant criterion for sorting decisions in our experiment. Finally, we find that cortisol levels are severely elevated at the beginning of the experiment, suggesting that participants experience stress in anticipation of the experiment per se, potentially due to uncertainties associated with the unknown lab situation. We call this the novelty effect.

The use of real decision-making incentives remains under debate after decades of economic experiments. In time preferences experiments involving future payments, real incentives are particularly problematic due to between-options differences in transaction costs, among other issues. What if hypothetical payments provide accurate data which, moreover, avoid transaction cost problems? In this paper, we test whether the use of hypothetical or one-out-of-ten-participants probabilistic—versus real—payments affects the elicitation of short-term and long-term discounting in a standard multiple price list task. We analyze data from a lab experiment in Spain and well-powered field and online experiments in Nigeria and the UK, respectively (N = 2,038). Our results indicate that the preferences elicited using the three payment methods are mostly the same: we can reject that either hypothetical or one-out-of-ten payments change any of the four preference measures considered by more than 0.18 SD with respect to real payments.

Rational choice theory, including models of social preferences, is challenged by decades of robust data from public good games. Provision of public goods, funded by lump-sum taxation, does not crowd out private provision on a one-for-one basis. Provision games elicit more of a public good than payoff-equivalent appropriation games. This paper offers a morally monotonic choice theory that incorporates observable moral reference points and is consistent with the two empirical findings. The model has idiosyncratic features that motivate a new experimental design. Data from our new experiment and three previous experiments favor moral monotonicity over alternative models including rational choice theory, prominent belief-based models of kindness, and popular reference-dependent models with loss aversion.