Efficient coordination is a major source of efficiency gains. We study in an experimental coordination game with 727 children and teenagers, aged 9 to 18 years, the strategies played in pre-adulthood. In our one-shot, experimental coordination game, we vary the incentives for reaching the more efficient equilibrium and the number of subjects within a group. Looking at strategy choices dependent on age, we do not find robust age effects in the aggregate. Yet, we see that smaller group sizes and larger incentives increase the likelihood of choosing the efficient strategy. The larger strategic uncertainty in larger groups is obviously harmful for overall efficiency. Regarding incentives, we find that increasing the profits in the efficient equilibrium seems to work better than providing a cushion in case of miscoordination. Beliefs play an important role as well, as subjects are more likely to play the efficient strategy when they expect others to do so as well. Our results are robust to controlling for individual risk-, time-, and social preferences.

Individuals often need to self-promote for social and professional recognition. In this paper, we investigate the existence of a gender gap in self-promotion of a prosocial action and explore its link with modesty norms. Using a novel experiment that combines both lab and field elements, we show that women are up to five times less likely to self-promote than men. We find suggestive evidence that the difference in behaviour across gender is determined by women’s social image concerns of being perceived as immodest. We find that the provision of a justification to self-promote has two important consequences: (i) it leads to an increase in self-promotion by women and (ii) contributes to the elimination of the gender gap in self-promotion behaviour.

This introduction presents the two-part Special Issue of honoring the life and work of Amnon Rapoport (1936–2022), a pioneering scholar whose six decades of research shaped experimental studies of interactive decision making. Rapoport’s hallmark was the interplay between formal game-theoretic modeling and rigorous laboratory testing, advancing understanding in coalition formation, social dilemmas, market entry, traffic networks, decision timing, resource dilemmas, behavioral operations, and methodological innovation. The 27 articles collected across the volumes revisit and extend these themes, offering fresh insights into how rationality assumptions succeed and fail in predicting human behavior. Together, the contributions reflect both continuity with Rapoport’s intellectual credo—“model first, test second, refine third”—and renewal through new methods and applications. Beyond scholarship, the issue pays tribute to Rapoport’s extraordinary role as a mentor and his enduring influence on the evolution of behavioral and experimental economics

In the presence of a default option, the optimal search rule for an agent with a reference-dependent utility and a search cost predicts: (i) the default increases the reservation utility due to the reference effect, leading to a better choice, and (ii) those with higher reservation utility will self-select into search and are more likely to find a superior option. Our experiments document the presence of both effects. Those who reject the default are likely to find higher-ranked options in their active search, supporting the self-selection effect. Even when the self-selection channel is shut down, the reference effect remains.

Social interactions frequently take place under the shadow of the future. Previous literature explains cooperation in indefinitely repeated prisoner’s dilemma as driven predominantly by self-interested strategic considerations. This paper provides a causal test of the importance of social preferences in such contexts. In a series of pre-registered experiments, we show that high levels of cooperation can be sustained when prosocial individuals interact in segregated groups. By comparing their behavior with that of mixed and selfish groups, we highlight the conditions under which other-regarding motivations matter in repeated interactions.

While market design advocates for the importance of good design to achieve desirable properties, experiments on coalition formation theory have shown fragility in proposed mechanisms to do so. We experimentally investigate the effectiveness of “structured” mechanisms that implement the Shapley value as an ex ante equilibrium outcome with those of corresponding “semi-structured” bargaining procedures. We find a significantly higher frequency of grand coalition formation and higher efficiency in the semi-structured than in the structured procedures regardless of whether they are demand-based or offer-based. While significant differences in the resulting allocations are observed between the two structured procedures, little difference is observed between the two semi-structured procedures. Finally, the possibility of free-form chat induces an equal division more frequently than occurs without it. Our results suggest that when it comes to bargaining and coalition formation, not having various restrictions imposed by different mechanisms may lead to more desirable outcomes.

We report a lab experiment to study subjects’ preferences over their ordinal rank in an earnings distribution. Following an assignment of unequal earnings, subjects can select a monetary transfer from exactly one individual to another, not including themselves. This can potentially change their own position in the distribution, as well as influence overall inequality. The experiment varies whether the initial earnings assignment is random or is affected by preliminary competition. It also varies the reference group from a complete to a partial network. A majority of observed transfers reduce inequality by moving earnings from those with the highest rank to the lowest rank in the distribution. Rank-improving transfers are substantially more common for preliminary competition losers than winners. Transfers to individuals outside of the reference group are not uncommon, and they usually target as the source the individuals high in the income distribution. While generally weak overall, own rank preferences appear to be more common among men than women.

In two sets of novel laboratory experiments, we show that the mere presence of an existing alliance at the onset of coalition formation may lead managers to form economically suboptimal alliances. Study Set 1 considers alliance formation when a focal firm is already embedded in an existing coalition. These studies show evidence of a status quo bias: participants managing the focal firm tend to include the current partner in alliance offers and thus are less successful in forming optimal alliances compared to those in an unattached control condition. Study Set 2 examines the extent to which an unattached focal firm attempts to ‘poach’ away attractive coalition partners from their embedded alliances. Our results show evidence of poaching avoidance: participants make fewer offers to, and are less likely to partner with, an attractive firm already in an alliance. However, this tendency to avoid poaching may be attenuated when the existing coalition is perceived as a powerful threat and/or alternate partners are unavailable. These findings provide behavioral insights into how judgmental biases can constrain alliance formation. We conclude with a discussion of how selected environmental, firm, and decision-maker characteristics (e.g., turbulence, embedded relationships, and risk orientation) may moderate these results.

We report two meta-analyses on the determinants of antisocial behavior in experimental settings in which such behavior is not rationally motivated by pecuniary incentives. The first meta-analysis employs aggregate data from 95 published and unpublished studies (24,086 participants), using laboratory, field and online experiments carried out since 2000. We find that antisocial behavior depends significantly on the experimental setting, being highest in vendetta games and lowest in social dilemmas. As we find significant heterogeneity across the studies, including across game classes, in the second meta-analysis, we focus only on “Joy of Destruction” (JoD) and money-burning (MB) experiments, for which we have the most observations, 51 studies and around 16,784 participants. Overall, our findings suggest that procedural fairness and being observed by others reduce the frequency of antisocial behavior. Online and field experiments display more antisocial behavior than laboratory experiments. We also find that the strategy method biases antisocial behavior upward. However, we do not find evidence for a positive publication bias being correlated with higher destructive behavior, either in the general meta-analysis or in relation to JoD/MB experiments; if anything, there is evidence of a negative publication bias. The JoD/MB meta-analysis finds evidence of a price effect for destruction frequency, negative discrimination against outsiders, within-subject designs underestimating destructive behavior, and more antisocial behavior in one-shot interactions. Collectively, our results point to the value of more laboratory experiments that systematically build on paradigmatic experimental designs to enable comparability and the identification of key economic drivers of antisocial behavior.

Explicit and implicit incentives and opportunities for mutually beneficial voluntary cooperation coexist in many economic relationships. In a series of eight laboratory gift-exchange experiments, we show that incentives can lead to crowding out of voluntary cooperation even after they have been abolished. This crowding-out also occurs in repeated relationships, which otherwise strongly increase effort compared to one-shot interactions. Using a unified econometric framework, we unpack these results as a function of positive and negative reciprocity, as well as the principals’ wage offer and the incentive compatibility of the contract. Crowding-out occurs mostly due to reduced wages and not a change in reciprocal wage–effort relationships. Our systematic analysis also replicates established results on gift exchange, incentives, and crowding out of voluntary cooperation while being exposed to incentives. Overall, our findings show that the behavioral consequences of explicit incentives strongly depend on the features of the situation in which they are embedded.

How do bribes and lobbying distort judgment? In our experiment, referees are tasked with judging a worker’s performance, and awarding a bonus to workers who score above a certain threshold. We find that bribes and lobbying are both distortionary, but in different ways. Whereas lobbying increases the number of workers receiving a bonus, bribes weaken the relationship between performance and success, with bonuses mostly being awarded to workers who bribe. We discuss implications for anti-corruption interventions.

We conduct an economic experiment to examine the causal impact of social ties on the preference for competition. Participants decide whether to engage in a competition or not. Across four treatments, potential competitors vary based on their relationship with the decision-maker: whether they had a conversation with the decision-maker prior to the competition, whether they are expected to chat after the competition, or both, or neither. We find that the process of chatting increases social closeness. This increase in social closeness tends to reduce the preference for competition when participants are expected to meet again after the competition. However, it does not change the likelihood of opting for competition if there is no prospect of further interaction. Through this experiment, we thus uncover previously unknown implications of managerial practices, such as team-building exercises and remote work options, that influence the formation of social ties.

This paper investigates the collusive and competitive effects of algorithmic price recommendations on market outcomes. These recommendations are often non-binding and common in many markets. We develop a theoretical framework and derive two algorithms that recommend collusive pricing strategies. Utilizing a laboratory experiment, we find that sellers condition their prices on the recommendation of the algorithms. The algorithm with a soft punishment strategy lowers market prices and has a pro-competitive effect. The algorithm that recommends a subgame perfect equilibrium strategy increases the range of market outcomes, including more collusive ones.

We performed a field experiment in Uruguay in which a 20-year-old chooses between a socially visible and a non-socially visible good after a friend randomly received one of these goods or an unknown one. We find no differences in choices when the friend received the nonvisible good instead of the unknown one. However, decision-makers significantly changed their allocation when their friend received the visible good. Consistent with status concerns driving the results, those in a disadvantaged position consumed more and those in an advantaged position consumed less of the visible good. These findings constitute the first experimental evidence of Duesenberry’s demonstration effects and show that status consumption is a relevant phenomenon among the youth in a developing country setting.

Over the last four decades, a broad stream of experimental literature has been published using the Common Pool Resource (CPR) game to study how people react to congestible resources, and how to keep such resources from socially harmful overexploitation. With the goal of providing guidance to future work on this still-important paradigm, we provide a narrative review of the literature, summarizing the results for several key aspects of the experimental operationalization. We classify these aspects into two broad categories. The first describes ‘environmental’ assumptions on the modeled resource problem itself. This refers to aspects of the experimental environment reflecting factors such as group size, resource size and asymmetry of access, which generally constitute the nature of the dilemma. The second category involves ‘institutional’ issues related to how people might solve the problem, such as user communication between subjects, information about previous subjects’ choices, and regulatory measures.

Narrow bracketers who are myopic in specific decisions would fail to consider preexisting risks in investment and neglect hedging opportunities. Growing evidence has demonstrated the relevance of narrow bracketing. We take a step further in empirical investigation and study individual heterogeneity in narrow bracketing. Specifically, we use a lab experiment in investment and hedging that elicits subjects’ preferences on rich occasions to uncover the individual degree of narrow bracketing without imposing distributional assumptions. Combining prospect theory and narrow bracketing can explain our findings: Subjects who invest more also insure more, and subjects insure significantly less in the loss domain than in the gain domain. More importantly, we show that the distribution of the individual degree of narrow bracketing is skewed at two extremes, yet with a substantial share of people in the middle who partially suffer from narrow bracketing. Neglecting this aspect, we would overestimate the severity of narrow bracketing and misinterpret its relation with individual characteristics.

Volunteering is a widespread allocation mechanism in the workplace. It emerges naturally in software development or the generation of online knowledge platforms. Using a field experiment with more than 2,000 workers, we study the effect of team size on volunteering in an online labor market. In contrast to our theoretical predictions and previous research, we find no effect of team size on volunteering, although workers react to free-riding incentives, and volunteering is perceived as costly. Eliciting workers’ beliefs about their co-workers’ volunteering reveals conditional volunteering as the primary driver of our results: Workers tend to volunteer more when they believe that others are volunteering, even when doing so is highly inefficient. Using additional experiments, we identify the importance of the task itself as an essential mitigating factor for those results.

Previous studies have shown that an oath can reduce lying in individual settings. Can it reduce lying in groups, a context where lying is more prevalent? Results from a lab experiment reveal that the impact depends on the incentive structures and procedures. A mandatory oath reduces lying when group members’ payoffs are independent, but only has a marginal effect when payoffs are dependent. Voluntary oath-taking enhances the effectiveness under both incentive structures by fostering intrinsic motivation to keep promises. The findings highlight the importance of peer effects and oath-taking procedures on the effectiveness of an oath in group settings.

In a field experiment where revelation of co-worker earnings and the shape of the earnings distribution are exogenously controlled, I test whether relative earnings information itself influences effective labor supply and labor supply elasticity. Piece-rate workers shown their peer earnings standing provide significantly more labor effort. However, the productivity boost from earnings disclosure disappears when inequalities in the underlying piece rate exist. By cross-randomizing net of tax piece rates, labor supply elasticity with respect to the net of tax wage is also estimated. Unlike labor level, I find this labor elasticity is unchanged by the relative standing information. Taken together, these findings have direct implications for how to best model relative status concerns in utility functions, supporting some and precluding other common ways. More speculatively, they also suggest social comparisons could be strategically used to grow firm output or the tax base, and, that underlying inequalities in compensation schemes inhibit the ability of social comparisons to incentivize work.

Wrong-doers may try to collaborate to achieve greater gains than would be possible alone. Yet potential collaborators face two issues: they need to accurately identify other cheaters and trust that their collaborators do not betray them when the opportunity arises. These concerns may be in tension, since the people who are genuine cheaters could also be the likeliest to be untrustworthy. We formalise this interaction in the ‘villain’s dilemma’ and use it in a laboratory experiment to study three questions: what kind of information helps people to overcome the villain’s dilemma? Does the villain’s dilemma promote or hamper cheating relative to individual settings? Who participates in the villain’s dilemma and who is a trustworthy collaborative cheater? We find that information has important consequences for behaviour in the villain’s dilemma. Public information about actions is important for supporting collaborative dishonesty, while more limited sources of information lead to back-stabbing and poor collaboration. We also find that the level of information, role of the decision maker, and round of the experiment affect whether dishonesty is higher or lower in the villain’s dilemma than in our individual honesty settings. Finally, individual factors are generally unrelated to collaborating but individual dishonesty predicts untrustworthiness as a collaborator.