We study the distributional preferences of Americans during 2013–2016, a period of social and economic upheaval. We decompose preferences into two qualitatively different tradeoffs—fair-mindedness versus self-interest, and equality versus efficiency—and measure both at the individual level in a large and diverse sample. Although Americans are heterogeneous in terms of both fair-mindedness and equality-efficiency orientation, we find that the individual-level preferences in 2013 are highly predictive of those in 2016. Subjects that experienced an increase in household income became more self-interested, and those who voted for Democratic presidential candidates in both 2012 and 2016 became more equality-oriented.

We investigate the effect of team formation and task characteristics on performance in high-stakes team tasks. In two field experiments, randomly assigned teams performed significantly better than self-selected teams in a task that allowed for an unequal work distribution. The effect was reversed if the task required the two team members to contribute more equally. Investigating mechanisms, we observe that teams become more similar in ability and report to cooperate better when team members can choose each other. We show how different levels of skill complementarity across tasks may explain our results: If team performance largely depends on the abilities of one team member, random team assignment may be preferred because it leads to a more equal distribution of skills across teams. However, if both team members’ abilities play a significant role in team production, the advantage of random assignment is reduced, and the value of team cooperation increases.

This article surveys the use of nonparametric permutation tests for analyzing experimental data. The permutation approach, which involves randomizing or permuting features of the observed data, is a flexible way to draw statistical inferences in common experimental settings. It is particularly valuable when few independent observations are available, a frequent occurrence in controlled experiments in economics and other social sciences. The permutation method constitutes a comprehensive approach to statistical inference. In two-treatment testing, permutation concepts underlie popular rank-based tests, like the Wilcoxon and Mann–Whitney tests. But permutation reasoning is not limited to ordinal contexts. Analogous tests can be constructed from the permutation of measured observations—as opposed to rank-transformed observations—and we argue that these tests should often be preferred. Permutation tests can also be used with multiple treatments, with ordered hypothesized effects, and with complex data-structures, such as hypothesis testing in the presence of nuisance variables. Drawing examples from the experimental economics literature, we illustrate how permutation testing solves common challenges. Our aim is to help experimenters move beyond the handful of overused tests in play today and to instead see permutation testing as a flexible framework for statistical inference.

We design a lab-in-the-field experiment involving naturally occurring groups operating in three South-African townships. We introduce an incentives-based mechanism named “participatory incentives” consisting of monetary incentives that are awarded conditional on the group reaching a threshold of minimum level of joint contribution to a common project or good. We show that participatory incentives significantly raise average contribution levels (from 29 to 62% of the endowment) and are even more effective in the presence of highly deprived people. We complement the reduced form estimations of the experimental data with a structural model that sheds light on the role of subjects’ beliefs and responsiveness to a social norm of high cooperation.

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.

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.

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.

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.

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 publicly 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.