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International audience; Motivated by recent research on product differentiation, we conduct laboratory experiments to study how demand uncertainty influences firms' incentives to differentiate. We ground our experiment on a discrete version of the standard location-then-price game introduced by \cite{Hotelling_1929}, and we consider different levels of demand uncertainty. We first derive the game equilibrium assuming risk-neutral firms, and obtain the standard prediction that a high level of demand uncertainty generates more differentiation. Second, we extend the analysis to consider non risk-neutral firms and markets with asymmetric risk profiles. We show that the game equilibrium can differ substantially according to the attitude to risk. Third, we compare our predictions with the experimental data and find that demand uncertainty acts as a differentiation force in the context of both symmetric markets composed of risk-neutral or risk-lover subjects and asymmetric markets. We find support also for the agglomeration effect arising from demand uncertainty for sufficiently risk-averse subjects. Overall, these results might explain the opposite product differentiation strategies frequently observed in markets with fast-evolving tastes (i.e. minimum or maximum differentiation). Finally, the data confirm that subjects differentiate to relax price competition and provide evidence of a strong positive relationship between differentiation and prices.

Worrisome topics, such as climate change, economic crises, or the Covid-19 pandemic, are increasingly present and pervasive due to digital media and social networks. Do such worries affect cognitive performance? The effect of a distressing topic might be very different depending on whether people have the scope and means to cope with the consequences. It can also differ by how performance is rewarded, for instance, if is there a goal that people can focus on. In an online experiment during the Covid-19 pandemic, we test how the cognitive performance of university students responds to topics discussing (i) current mental health issues related to social restrictions or (ii) future labor market uncertainties linked to the economic contraction. Moreover, we study how the response is affected by a performance goal by conditioning payout on reaching a minimum level. We find that the labor market topic increases cognitive performance when performance is motivated by a goal. Conversely, there is no such effect after the mental health topic. We even find a weak negative effect among those mentally vulnerable when payout is not based on reaching a goal. The positive effect is driven by students with larger financial and social resources, pointing at an inequality-widening mechanism.

International audience; Through a series of experiments, this paper tests the relative efficiency of persuasion and commitment schemes to increase and sustain contribution levels in a Voluntary Contribution Game. The design allows us to compare a baseline consisting of a repeated public good game to four treatments of the same game in which we successively introduce a persuasion message, commitment devices, and communication between subjects. Our results suggest that these non-monetary procedures significantly increase cooperation and reduce the decay of contributions across periods.

In more and more situations, artificially intelligent algorithms have to model humans’ (social) preferences on whose behalf they increasingly make decisions. They can learn these preferences through the repeated observation of human behavior in social encounters. In such a context, do individuals adjust the selfishness or prosociality of their behavior when it is common knowledge that their actions produce various externalities through the training of an algorithm? In an online experiment, we let participants’ choices in dictator games train an algorithm. Thereby, they create an externality on future decision making of an intelligent system that affects future participants. We show that individuals who are aware of the consequences of their training on the pay- offs of a future generation behave more prosocially, but only when they bear the risk of being harmed themselves by future algorithmic choices. In that case, the externality of artificially intelligence training induces a significantly higher share of egalitarian decisions in the present.

This paper develops a theoretical framework to think about employees' effort choices, and applies this framework to assess the ability of existing laboratory designs to identify the effect of pay inequality on worker effort. The analysis shows that failure to control for a number of confounds-such as reciprocity towards the employer in multilateral gift-exchange games (vertical fairness), or the incentive to increase effort when feeling underpaid under piece rates (income targeting)-may lead to inaccurate interpretation of evidence of treatment effects. In light of these findings, the paper provides a set of recommendations on how to improve identification in the design of laboratory experiments in the future.

L’interaction entre la capacite creative individuelle et la maniere de l’ameliorer est une question qui presente un enorme potentiel pour l’analyse economique. Dans cette etude, nous nous attardons sur la question en nous concentrant sur les avantages methodologiques d’une approche experimentale. Nous fournissons une revue de la litterature en economie experimentale sur la creativite, en identifiant sept principaux objets d’etude. A savoir, l’impact sur la creativite : (1) des incitations monetaires faibles ou elevees (2) de l’interaction entre les incitations monetaires et les tâches, (3) de la concurrence au sein du groupe (4) de la cooperation au sein du groupe, (5) des facteurs culturels, (6) des incitations sociales non monetaires, et (7) du comportement strategique. Nous classons egalement les etudes de notre revue en fonction des caracteristiques cles des procedures experimentales standard en economie, telles que le type de tâche creative, la maniere dont elle est evaluee et le groupe de sujets specifique. Cette comparaison multidimensionnelle nous permet de conclure que l’absence actuelle de resultats solides sur les determinants de la creativite en economie pourrait etre due a l’absence d’etudes experimentales comparables dans les memes conditions experimentales. Notre revue souligne egalement le role crucial des recherches anterieures sur la creativite dans la litterature psychologique dans l’elaboration des procedures d’incitation a la creativite en economie experimentale.Classification JEL : C91, C92, D91, O31.

The present study proposes a theoretical model that investigates how R&D productivity influences the relationship between product substitutability and R&D investment in a duopolistic market. We argue that the effects on R&D investment are more complex than the previous literature suggests. We show theoretically that, in unlevelled industries, the laggard’s R&D investment decreases with product substitutability regardless of the R&D productivity level. In sharp contrast, in levelled industries, whether R&D investment increases or decreases with product substitutability depends crucially on the level of the R&D productivity. We choose parameters and formulate testable predictions that we take to the laboratory. We find that subjects’ behavior is largely consistent with the model’s predictions.

National audience; We study how the random assignment of new students to introductory-week groups shapes subsequent friendship networks. Both women and men report being much more likely to be friends with same-gender students with whom they were (randomly) assigned in a group during their first week on campus, and the effect is much stronger for women. When students from the same cohort play a repeated trust game in the experimental laboratory, their behavior helps explain what we observed in the field. Women display more stability and less flexibility than men in their interactions with individuals with whom they had previously played. This difference is enough to generate homophily in the observational data even though subjects show no intrinsic preference for same-gender interaction.

We experimentally study how individuals read strategically-transmitted information when they have preferences over what they will learn. Subjects play disclosure games in which Receivers should interpret messages skeptically. We vary whether the state that Senders communicate about is ego-relevant or neutral for Receivers, and whether skeptical beliefs are aligned or not with what Receivers prefer believing. Skepticism is lower when skeptical beliefs are self-threatening than in neutral settings. When skeptical beliefs are self-serving, skepticism is not enhanced compared to neutral settings. These results demonstrate that individuals' exercise of skepticism depends on the conclusions of skeptical inferences.

International audience

International audience; This study examines factors determining farmers' investment in organic farming using a contextualized lab-in- the-field experiment with 220 small household farmers in Northern Vietnam. We focus on the role of network structure, information nudge, and social comparison between farmers using three types of networks: circle, star and complete. Our results suggest that, on average, around 64% of the land is invested in organic farming in the complete network in which each farmer is connected to all of the others, while only about 57% of the land is invested in the circle and star network. Moreover, social comparison (i.e., information about the average in-vestment) performs better in a circle network than in a star network. Finally, information nudges about the socially optimal investment could encourage farmers' coordination in all three networks, particularly in the complete network with an increase in organic investment up to 76%.

National audience; The New Keynesian theory of inflation determination is tested in this paper by means of laboratory experiments. We find that the Taylor principle is a necessary condition to ensure convergence to the inflation target, but it is not sufficient. Using a behavioral model of expectation formation, we show how heterogeneous expectations tend to self-organize on different forecasting strategies depending on monetary policy. Finally, we link the central bank’s ability to control inflation to the impact that monetary policy has on the type of feedback –positive or negative– between expectations and realizations of aggregate variables and in turn on the composition of subjects with respect to the type of forecasting rules they use.

International audience; Do observers judge differently a wrongdoer when s/he does not exploit a situation to its maximum extent? Using a social intuitionist perspective and taking into account the reference point bias, we hypothesize that people will judge a wrongdoing less severely when the situation is not exploited to its fullest extent. We run two experimental surveys in France and examine whether various wrongdoings performed in the business realm (overcharging travel expenses, overstating work hours, pollution) are judged less severely when different reference points are suggested: (i) no explicit reference point is mentioned, (ii) a reference point is mentioned and the maximum extent is reached, (iii) a reference point is mentioned but the maximum extent is not reached and (iv) the participant is invited to elicit a reference point corresponding to what s/he considers as the maximum extent. Our findings support that participants judge a wrongdoer less severely, when a reference point mentioning that s/he has not exploited the situation to its fullest extent is indicated or elicited. Our findings suggest that partial cheaters could emphasize their self-restraint to mitigate judgment and punishment if they get caught. We draw some managerial and policy implications.

International audience; In a stock market experiment, we examine how regret avoidance influences the decision to sell an asset while its price changes over time. Participants know beforehand whether they will observe the future prices after they sell the asset or not. Without future prices, participants are affected only by regret about previously observed high prices (past regret), but when future prices are available, they also avoid regret about expected after-sale high prices (future regret). Moreover, as the relative sizes of past and future regret change, participants dynamically switch between them. This demonstrates how multiple reference points dynamically influence sales. (JEL C91, G12, G41)

We consider the external validity of laboratory measures of risk attitude. Based on a large-scale experiment using a representative panel of the Dutch population, we test if these measures can explain two different types of behavior: (i) behavior in laboratory risky financial decisions, and (ii) behavior in naturally-occurring field behavior under risk (financial, health and employment decisions). We find that measures of risk attitude are related to behavior in laboratory financial decisions and the most complex measures are outperformed by simpler measures. However, measures of risk attitude are not related to risk-taking in the field, calling into question the methods currently used for the purpose of measuring actual risk preferences. We conclude that while the external validity of measures of risk attitude holds in closely related frameworks, this validity is compromised in more remote settings.

International audience; This paper presents an artefactual field experiment with craftsmen working on renovation projects to assess the effect of training programs and incentive schemes on coordination. Workers frequently fail to coordinate their tasks when not supervised by a project coordinator. This is particularly important in the construction sector where it leads to a lack of final performance in buildings. We introduce two different incentives: a first contract paying craftsmen only according to their individual performance, and a second contract paying a group of three craftsmen with a weak-link payment according to the group’s worst performance. In addition, we test these incentives on two different subject groups: one is composed of craftsmen trained to coordinate their tasks, and the others are not. The results suggest that trained subjects coordinate at significantly higher effort levels than non-trained subjects when facing an individual-based incentive. However, when facing a group-based incentive, non-trained subjects seem to ”catch up” trained subjects in terms of coordination level, while these latter subjects do not significantly increase their performance level.

International audience; We investigate whether and how an individual giving decision is affected in risky environments in which the recipient's wealth is random. We demonstrate that, under risk neutrality, the donation of dictators with a purely ex post view of fairness should, in general, be affected by the riskiness of the recipient's payoff, while dictators with a purely ex ante view should not be. Furthermore, we observe that some influential inequality aversion preferences functions yield opposite predictions when we consider ex post view of fairness. Hence, we report on dictator games laboratory experiments in which the recipient's wealth is exposed to an actuarially neutral and additive background risk. Our experimental data show no statistically significant impact of the recipient's risk exposure on dictators' giving decisions. This result appears robust to both the experimental design (within subjects or between subjects) and the origin of the recipient's risk exposure (chosen by the recipient or imposed on the recipient). Although we cannot sharply validate or invalidate alternative fairness theories, the whole pattern of our experimental data can be simply explained by assuming ex ante view of fairness and risk neutrality.

International audience; Tests of labor supply models often rely on wages. However, wage variation alone generally cannot disentangle the classical time separable model and its extensions: reference dependent preferences (income targeting) and time nonseparable preferences (disutility spillovers; timing-specific preferences). We set up a novel laboratory experiment in which individuals choose their working time. We vary, independently, wages, historical income paths, and cumulative past work. We also vary the timing of experimental sessions. Statistical tests and stochastic revealed preference methods cannot reject the classical model in favor of income targeting or disutility spillovers, but the data suggest that labor supply varies by time-of-the-day.

International audience New plant engineering techniques (NPETs) may significantly improve both production and quality of foods. Some consumers and regulators around the world might be reluctant to accept such products and the global market penetration of these products may remain low. We develop a parsimonious economic model for R&D investment in food innovations to identify conditions under which NPET technology emerges in the context of international trade. The framework integrates consumers' willingness to pay (WTP) for the new food, the uncertainty of R&D processes, the associated regulatory cost of approval, and the competition between domestic and foreign products. With generic applicability, the model enables the quantitative analysis of new foods that could be introduced in markets and then traded across borders. We apply the framework to a hypothetical case of apples improved with NPETs. Simulation results suggest that import bans and high values of sunk cost can reduce R&D investment in NPETs to suboptimal levels. Les nouvelles techniques d'ingénierie végétale (NTIV) peuvent améliorer considérablement la production et la qualité des aliments. Certains consommateurs et régulateurs du monde entier pourraient être réticents à accepter de tels produits et l’introduction de ces produits sur le marché mondial pourrait rester faible. Nous développons un modèle économique prenants en compte l'investissement en R&D dans les innovations alimentaires afin d'identifier les conditions dans lesquelles la technologie NTIV émerge dans un contexte de commerce international. Le cadre intègre le consentement à payer des consommateurs (CAP) pour le nouvel aliment, l'incertitude des processus de R&D, le coût réglementaire associé à l'approbation et la concurrence entre les produits nationaux et étrangers. Le modèle permet l'analyse quantitative de l’apparition de nouveaux aliments qui pourraient être introduits sur les marchés puis commercialisés au-delà des frontières. Nous appliquons le modèle à un cas hypothétique de pommes améliorées avec des NTIV. Les résultats de la simulation suggèrent que les interdictions d'importation et les valeurs élevées de coûts fixes peuvent réduire les investissements en R&D dans les NTIV à des niveaux sous-optimaux.

The projection bias corresponds to the human tendency to project current preferences into the future as if present preferences will remain unchanged, omitting a range of external influences over the current preferences. We design a survey experiment to investigate the projection bias relevance on two environmentally friendly initiatives, namely solar panels and eco-friendly transport. We found that beliefs and behavioral intentions are subject to positive change when individuals are solicited a day when the weather is congruent with the proposed changes. We draw several policy and managerial implications for environmental issues.

francaisL’ethique strategique : l’altruisme epure de l’effet de la consideration pour autrui Dans un jeu d’investissement et effort en deux etapes, nous modelisons l’investissement « altruiste » dans la capacite d’un autre agent a beneficier des synergies entre les efforts des deux agents. Notre analyse theorique est developpee en supposant que les agents ne retirent pas une utilite directe de leur investissement « altruiste », c’est-a-dire sans tenir compte des preferences des autres au sein de leur propre utilite. Les resultats d’une experience en laboratoire confirment notre prediction comportementale que, pour un cout d’investissement suffisamment bas, les sujets se coordonnent sur un investissement positif, ce qui, a son tour, augmente leur effort dans la deuxieme etape. Cet effort depend positivement a la fois du propre investissement et de celui de l’autre agent, tel que prevu par notre modele. Ce comportement est observe independamment des preferences des sujets a l’egard du risque et de l’inegalite. EnglishIn a two-stage investment-effort game, we model altruistic investment in another agent’s capacity to benefit from synergies between the two agents’ efforts. We conduct the theoretical analysis of the game by assuming that agents who invest in others have no direct utility from their giving behavior, i.e., without considering other-regarding preferences. Results of a laboratory experiment confirm our behavioral prediction that, for a low enough investment cost, subjects coordinate on a positive complementarity-building investment, which in turn boosts their effort in the second stage. The latter increases in both own and others’ complementarity-building investment, as predicted by our model. All this holds independently of subjects’ risk and inequity aversion.

L’objet de cet article est d’analyser de maniere experimentale les liens supposes entre les preferences sociales des individus et la maniere dont ils concoivent la propriete intellectuelle, en opposant en particulier les approches utilitaristes et deontologiques. Pour ce faire, nous avons mis en place un protocole experimental original a l’interface de deux courants de litterature : l’un, bien etabli, traitant des preferences sociales ; l’autre, naissant, tentant de capter les differentes justifications de l’existence de la propriete intellectuelle. Notre experience aboutit a deux enseignements majeurs : 1) les sujets utilitaristes semblent changer de conception de la justice sociale des lors que la question de la propriete intellectuelle est posee ; 2) les sujets rawlsiens sont en parfaite coherence avec l’approche deontologique de la propriete intellectuelle, donnant la priorite aux droits des auteurs et des inventeurs, tout en minimisant les inegalites pouvant en resulter en optant, par exemple, en faveur d’une duree courte de propriete intellectuelle.

We study the reaction of investors to tail events across trading institutions. We conduct experiments in which investors bid on a financial asset that delivers a small positive reward in more than 99% of the cases and a large loss otherwise. The baseline treatment uses a repeated BDM mechanism whereas the market treatment replaces the uniform draw of the BDM mechanism by a uniform draw over the bids of the other participants. Our design is such that bids should not differ across treatments in normal times while allowing for potential differences to emerge after tail events have occurred. We find that markets tend to exacerbate the reaction of investors to tail losses and we attribute this effect to emotions.

This paper reports two experiments in which attitudes towards temporal risk resolution is elicited from choices between two-outcome lotteries that pay out at some future fixed date and can be resolved either now or later. We show that matching probabilities provides a simple method to measure attitudes towards temporal resolution-via the utility scaleunder Kreps and Porteus' (1978) recursive expected utility. We also analyze our data using a general recursive model that can reveal attitudes towards temporal risk resolution through the utility scale and/or the probability weighting scale. In terms of goodness of fit, as well as of prediction accuracy, our results point to a better performance of the probability weighting approach. More specifically, we show that individuals become less sensitive and more pessimistic with respect to winning probabilities when lotteries are resolved later rather than now.

International audience; In this article, we use a contextualized lab experiment to test the effect of non-monetary incentives that can guide harvest professionals into adopting new sustainable harvesting practices. First, we test the effect of signing a declaration that commits wood buyers who voluntarily sign it to act in a sustainable manner. Second, we test the effect of priming by activating a concept of sustainability on subjects’ behaviour. Our results provide evidence that presenting a declaration to sign is effective in inducing subjects to act in a sustainable manner when personal and collective interests are not aligned and there are financial incentives to make decisions that are against environmental sustainability. However, sustainability priming does not have a significant impact on subjects’ behaviour. From a public policy point of view, a declaration is an effective tool and easy to implement by institutions aiming at fostering pro-environmental behaviour.

Pro-social individuals face a trade-off between their monetary and moral motives. Hence, they may be tempted to exploit the uncertainty in their decision environment in order to reconcile this trade-off. In this paper, we investigate whether individuals with belief-dependent preferences avoid the monetary cost of behaving according to their moral standards by strategically acquiring information about others' expectations. We test the predicitions of an information acquisition model in an online experiment. We use a modified trust-game in which we introduce uncertainty about the second movers' beliefs about first-movers' expectations. Our design enables to (i) identify participants with belief-based preferences and (ii) investigate their information acquisition strategy. Consistent with our predictions of subjective preferences, we find that most individuals classified as belief-dependent strategically select their source of information to avoid the cost of their conscience.

The aim of this article is to better understand how judgments about nudge acceptability are formed and whether they can be manipulated. We conducted a randomized experiment to test whether acceptability judgments could be (i) more favourable when the decision to implement the nudges was made following a consultation with the targeted population and (ii) influenced by the joint framing of the nudge's goal and effectiveness (in terms of an increase in desirable behaviour vs. decrease in undesirable behaviour). We tested these hypotheses on various nudge scenarios and obtained mixed results that do not clearly support our hypotheses. A surprising result that calls for further work is that by mentioning that a nudge had been implemented through a consultation with the targeted population its acceptability could be lowered.

International audience; In this stated preferences study, we describe for the first time French citizens’ preferences for various epidemic control measures, to inform longer-term strategies and future epidemics. We used a discrete choice experiment in a representative sample of 908 adults in November 2020 (before vaccination was available) to quantify the trade-off they were willing to make between restrictions on the social, cultural, and economic life, school closing, targeted lockdown of high-incidence areas, constraints to directly protect vulnerable persons (e.g., self-isolation), and measures to overcome the risk of hospital overload. The estimation of mixed logit models with correlated random effects shows that some trade-offs exist to avoid overload of hospitals and intensive care units, at the expense of stricter control measures with the potential to reduce individuals’ welfare. The willingness to accept restrictions was shared to a large extent across subgroups according to age, gender, education, vulnerability to the COVID-19 epidemic, and other socio-demographic or economic variables. However, individuals who felt at greater risk from COVID-19, and individuals expressing high confidence in the governmental management of the health and economic crisis, more easily accepted all these restrictions. Finally, we compared the welfare impact of alternative strategies combining different epidemic control measures. Our results suggest that policies close to a targeted lockdown or with medically prescribed self-isolation were those satisfying the largest share of the population and achieving high gain in average welfare, while average welfare was maximized by the combination of all highly restrictive measures. This illustrates the difficulty in making preference-based decisions on restrictions.

International audience; We test experimentally whether individuals high in some entrepreneurial characteristics are more likely to engage in destructive behavior than other individuals. In the joy-of-destruction game, participants can either preserve or costly burn the endowment of each other. In some treatments they can hide from other participants whether they are responsible for destruction. We found that participants high in some entrepreneurial characteristics are significantly more likely to adopt destructive behaviours.

International audience; We investigate whether peer effects at work differ by gender and whether gender differences in peer effects -if any- depend on work organization. We develop a social network model with gender heterogeneity that we test in a real-effort laboratory experiment. We compare sequential networks in which information flows from peers to the worker and simultaneous networks where it disseminates bi-directionally. We identify strong gender differences as females disregard their peers’ performance in simultaneous networks, while males are influenced by peers in both networks. Females may perceive the environment in simultaneous networks as being more competitive than in sequential networks.

An experiment is proposed in which the subjects could contribute to a public good which could be thought of as reducing pollution, which was stochastic. A nudge (announcement of the socially optimal contribution) and a tax are implemented to improve the level of contributions. The environmental sensitivity and optimism of the subjects are also elicited. Our first result shows that the implementation of the nudge does not perform as well as the implementation of the tax. The reaction to the nudge depends directly on individuals' environmental sensitivity, contrary to the reaction to the tax. Secondly, the nudge performs well with highly sensitive subjects only during the first half of its implementation. Lastly, the efficiency analysis shows that the implementation of the nudge significantly decreases the groups' welfare for the least sensitive subjects, in comparison to the baseline. (C) 2018 Elsevier B.V. All rights reserved.

We study a class of sender–receiver disclosure games in the lab. Our experiment relies on a graphical representation of sender's incentives in these games, and permits partial disclosure. We use local and global properties of the incentive graph to explain behavior and performance of players across different games. Sender types whose interests are aligned with those of the receiver fully disclose, while other types use vague messages. Receivers take the evidence disclosed by senders into account, and perform better in games with an acyclic graph. Senders perform better in games with a cyclic graph. The data is largely consistent with a non-equilibrium model of strategic thinking based on the iterated elimination of obviously dominated strategies.

International audience; We compare consumers’ attitude towards and willingness to pay (WTP) for gene-edited (GE) apples in Europe and the US. Using hypothetical choices in a lab and different technology messages, we estimate WTP of 162 French and 166 US consumers for new apples, which do not brown upon being sliced or cut. Messages center on (i) the social and private benefits of having the new apples, and (ii) possible technologies leading to this new benefit (conventional hybrids, GE, and genetically modified (GMO)). French consumers do not value the innovation and actually discount it when it is generated via biotechnology. US consumers do value the innovation as long as it is not generated by biotechnology. In both countries, the steepest discount is for GMO apples, followed by GE apples. Furthermore, the discounting occurs through “boycott” consumers who dislike biotechnology. However, the discounting is weaker for US consumers compared to French consumers. Favorable attitudes towards sciences and new technology totally offset the discounting of GE apples.; Nous comparons l’attitude des consommateurs et leur consentement à payer (CAP) pour des pommes modifiées via l’édition génétique (GE) en Europe et aux États-Unis. À partir de choix hypothétiques dans un laboratoire et de différents messages sur la technologie, nous estimons le CAP de 162 Français et 166 Américains pour les nouvelles pommes, qui ne brunissent pas après avoir été tranchées. Les messages sont centrés sur (i) les avantages sociaux et privés d'avoir de nouvelles pommes, et (ii) sur les technologies possibles menant à ces nouveaux avantages (hybrides conventionnelles, GE et génétiquement modifiés (OGM)). Les consommateurs français ne valorisent pas l'innovation, et ils la minimisent lorsqu'elle est générée par la biotechnologie. Les consommateurs américains apprécient l'innovation tant qu'elle n'est pas générée par la biotechnologie. Dans les deux pays, la diminution de CAP la plus forte concerne les pommes OGM, suivies par les pommes GE. Cependant, la diminution de CAP est plus faible pour les consommateurs américains que pour les consommateurs français. Les attitudes favorables envers les sciences et les nouvelles technologies compensent totalement la réduction des CAP pour les pommes GE.

International audience; We present a model for research and development (R&D) investment in food innovations based on new plant engineering techniques (NPETs) and traditional hybridization methods. The framework combines uncertain and costly food innovation with consumers' willingness to pay (WTP) for the new food. The framework is applied with elicited WTP of French and US consumers for new improved apples. NPETs may be socially beneficial under full information and when the probability of success under NPETs is relatively high. Otherwise, the traditional hybridization is socially optimal. A probable collapse of conventional apples raises the social desirability of new apples generated by NPETs and traditional hybridization.; Nous présentons un modèle d'investissement en recherche et développement (R&D) dans le domaine alimentaire, en prenant en considération les nouvelles techniques d'ingénierie végétale (NTIV) et les méthodes d'hybridation traditionnelles. Le modèle intègre une innovation alimentaire incertaine et coûteuse, ainsi que les consentements à payer des consommateurs (CAP) pour le nouvel aliment. Ce cadre conceptuel est appliqué au cas de nouvelles pommes se conservant plus longtemps et brunissant moins vite, en prenant en compte les CAP des consommateurs français et américains pour ces nouvelles pommes. Il est montré que les NTIV peuvent être socialement bénéfiques dans un contexte d’information complète, et lorsque la probabilité de succès avec ces NTIV est relativement élevée. Sinon, l'hybridation traditionnelle est socialement optimale. Une menace importante sur la production des pommes conventionnelles augmente la désirabilité sociale de nouvelles pommes générées par les NTIV ou l'hybridation traditionnelle.

As health care becomes increasingly personalized to the needs and values of individual patients, informational interventions that aim to inform and debias consumer decision-making are likely to become important tools. In a randomized controlled experiment, we explore the effects of providing participants with published fact boxes on the benefits and harms of common cancer screening procedures. Female participants were surveyed about breast cancer screening by mammography, while male participants were surveyed about prostate cancer screening by prostate-specific antigen (PSA) testing. For these screening procedures, we expect consumers to have overly optimistic prior beliefs about the benefits and harms. We find that participants update their beliefs only modestly and change their stated preferences to seek screening even more modestly. Participants who scored higher on a numeracy test updated their beliefs and preferences about screening more in response to the fact boxes than did patients who scored lower on the numeracy test. More-numerate subjects also seem to become more anxious in response to the risk information.

We study two well-known electronic markets: an over-the-counter (OTC) market, in which each trader looks for the best counterpart through bilateral negotiations, and a double auction (DA) market, in which traders post their quotes publicly. We focus on the DA–OTC efficiency gap and show how it varies with different market sizes (10, 20, 40, and 80 traders). We compare experimental results from a sample of 6400 undergraduate students in Economics and Management with zero-intelligence agent-based simulations. Simulation results show that the traded quantity increases with market size under both DA and OTC. Experimental results confirm the same tendency under DA, while the share of periods in which the traded quantity is lower than the efficient one increases with market size under OTC, ultimately leading to a DA–OTC efficiency gap increasing with the market size. We rationalize these results by putting forward a simple model of OTC market as a repeated bargaining procedure under incomplete information on buyers' valuations and sellers' costs. We show that efficiency decreases slightly with size due to two counteracting effects: acceptance rates in earlier interactions decrease with size, and earlier offers increase, but not always enough to compensate for the decrease in acceptance rates.

While much literature has focused on preferences regarding risk, preferences over skewness also have significant economic implications. An important and understudied aspect of skewness preferences is how they affect risk taking. In this paper, we design a novel laboratory experiment that elicits certainty equivalents over lotteries where the variance and skewness of the outcomes are orthogonal to each other. This design enables us to cleanly measure both skewness seeking/avoiding and risk taking behavior, and their interaction, without needing to make parametric assumptions. Our experiment includes both left- and right-skewed lotteries. The results reveal that the majority of subjects are skewness avoiding risk takers who correspondingly also take more risk when facing less skewed lotteries. Our second contribution is to link these choices to individual rank-dependent utility preference parameters estimated using a separate lottery choice protocol. Using a latent-class model, we are able to identify two classes of subjects: skewness avoiders with the classic inverse s-shaped probability weighting function and skewness neutral subjects that do not have an inverse s-shaped probability weighting function. Our results thus demonstrate the link between probability distortion and skewness seeking/avoidance choices. They also highlight the importance of accounting for individual heterogeneity. Supplementary Information The online version contains supplementary material available at 10.1007/s11166-021-09345-w.

International audience; The projection bias corresponds to the human tendency to project current preferences into the future as if present tastes remained unchanged. We apply the projection bias to the environmental domainand design a surveyexperiment to investigate its relevance on two environmentally friendly initiatives, namelysolar panels and eco-friendly transport. We found that some attitudes and behavioral intentions aresubject to positive changewhen individuals are soliciteda day when the weatheris congruent with the proposed changes. We draw several policy and managerial implications for ecological issues.

With Big Data, decisions made by machine learning algorithms depend on training data generated by many individuals. In an experiment, we identify the effect of varying individual responsibility for the moral choices of an artificially intelligent algorithm. Across treatments, we manipulated the sources of training data and thus the impact of each individual's decisions on the algorithm. Diffusing such individual pivotality for algorithmic choices increased the share of selfish decisions and weakened revealed prosocial preferences. This does not result from a change in the structure of incentives. Rather, our results show that Big Data offers an excuse for selfish behavior through lower responsibility for one's and others' fate.

We blend the institutional and social identity theories to explain why foreign companies may endure a differentiated treatment compared to domestic ones. We extend the “liability of foreignness” (LOF) reasoning to the moral domain. Using a survey experiment in Algeria and France, we examine whether observers judge similarly or differently the same ethical and unethical practices by manipulating the doers’ origin. Each treatment corresponds to a specific combination of company behavior (ethical vs. unethical) and company origin (no origin mentioned vs. domestic origin vs. foreign origin). We found that company origin matters for the ethical and some unethical scenarios. However, the foreignness consequences in the moral domain are not always consistent with a simplistic application of LOF-based arguments, leading us to consider a more complex picture than initially expected. In the Algerian sample, we found that foreign companies can even benefit from an advantage compared to domestic ones. JEL CLASSIFICATION F23; C91

Eliciting all the components of prospect theory –curvature of the utility function, weighting function and loss aversion– remains an open empirical challenge. We develop a semi-parametric method that keeps the tractability of parametric methods while providing more precise estimates. Using the data of Tversky and Kahneman (1992), we revisit their main parametric results. We reject the convexity of the utility function in the loss domain, find lower probability weighting, and confirm loss aversion. We also report that the probability weighting function does not exhibit duality and equality across domains, in line with cumulative prospect theory and in contrast with original prospect and rank dependent utility theories.

In a finitely repeated game with asymmetric information, we experimentally study how reputation and standard market mechanisms change the nature of fraudulent announcements by experts. While some lies can be detected ex post by investors, other lies remain deniable. Lying behavior suggests that individuals care more about the consequences of being caught, rather than the act of lying per se. Allowing for reputation reduces the frequency of lies that can be detected but has no impact on deniable lies: individuals simply hide their lies better and fraud persists. Competition without reputation increases risky lies and never protects investment.

International audience; Would people behave in more pro-environmentally after simply being exposed to a surrounding that is reminiscent of nature? In order to address this question, we carry out a laboratory experiment where we test participants' likelihood of carrying out two types of Pro-Environmental Behavior (PEB): a monetary effort of donating to an Environmental Non-Governmental Organization (ENGO) that we call an eco-donation, and a non-monetary effort of recycling that we call an eco-action. We construct three different decision-making frameworks through showing participants videos of an urban setting, a nature setting and a "positive emotions" setting (not linked to nature). We find that exposure to nature boosts both eco-donations and eco-actions. Our results highlight that there is no direct link between these PEB in terms of spillover effects. Interestingly, the impact of nature exposure on eco-donation is greater on individuals with a lowcenvironmental consciousness score, whereas the impact on eco-action is greater on individuals with a high level of environmental consciousness. Our work provides new avenues for designing environmental protection policies based on behavioral insights.

This paper reports data from a sender-receiver experiment that compares lying behavior between two groups of students, one in business administration and the other in medicine. We use a modified version of the sender-receiver deception game introduced by Erat and Gneezy (2012) to collect data on 393 subjects. The results show that both groups of students respond to incentives as expected: the frequency of lying is higher, the higher the benefit for the sender, and the lower the loss for the receiver is. For given payoffs, there is little difference between the two groups in the domain of white lies; however, business students resort to selfish lies more frequently than do medical students. Furthermore, the analysis does not confirm differences in altruism between the two groups. A representative survey reveals a substantial degree of coherence between the beliefs of the general public of France and behavior observed in this lab experiment.

We study choices and reaction times of respondents in an impunity game with unfair offers. The non-private impunity game features two roles, proposer and respondent, who are both aware whether the pie size is small or large. Proposers decide among three more or less unfair offers; respondents can accept or reject the offer, in which case it is lost for them. Whatever the responder decides is communicated to the proposer. 240 proposers took part in a traditional laboratory; 24 respondents were in an fMRI setup where they confronted all 240 proposals elicited from proposers. Responses were sent via email to proposers. Proposers revealed little concern for respondents. Respondents overwhelmingly rejected small offers, especially from a large pie. Surprisingly and in contrast with most of the literature and the Social Heuristic Hypothesis, we find that on average acceptances took longer than rejections. This result is driven by individual heterogeneity. The rich response data allow us to distinguish different respondent types, finding a remarkable consistency: subjects mainly accepting (rejecting) take more time to reject (accept). We attribute this finding to heterogeneity in self-priming. Our results suggest a primary role for individual heterogeneity in experiments testing the intuitive or deliberate status of cooperation and altruism.

International audience; Does feedback on success in a task increase individuals' beliefs about their chance to succeed in a subsequent, unrelated, task? Does feedback on failure have a symmetric effect? Is the distortion of beliefs, possibly due to motivated beliefs, mistakes in updating or the feeling of having a lucky day, heterogeneous across individuals, in particular according to their status in the society? Conducting an artefactual field experiment in India with participants from different castes, we show that feedback on success in a forced competition in a first task increases winners' self-confidence and competitiveness in the subsequent task. Such feedback spillovers on self-confidence are asymmetric and heterogeneous according to status and more likely for already more confident individuals.

This paper reviews studies conducted in naturally-occurring work environments or in the laboratory on the impact of performance feedback provision and peer effects on individuals' performance. First, it discusses to which extent feedback on absolute performance affects individuals' effort for cognitive or motivational reasons, and how evaluations can be distorted strategically. Second, this paper highlights the positive and negative effects of feedback on relative performance and rank on individuals' productivity and persistence, but also on the occurrence of antisocial behavior. Relative feedback stimulates effort by informing on the marginal return or the marginal cost of effort, and by activating behavioral forces even in the absence of monetary incentives. These behavioral mechanisms relate to self-esteem, status concerns, competitive preferences and social learning. Relative feedback sometimes discourages or distorts effort, notably if people collude or are disappointment averse. In addition to incentive schemes and social preferences, the management of self-confidence affects the way relative feedback impacts productivity. Third, the paper addresses the question of the identification of peer effects on employees' performance, their size, their direction and their heterogeneity along the hierarchy. The mechanisms behind peer effects include conformism, social pressure, rivalry, social learning and distributional preferences, depending on the presence of payoff externalities or technological and organizational externalities..

The projection bias corresponds to the human tendency to project current preferences into the future as if present tastes remained unchanged. We apply the projection bias to the environmental domain and design a survey experiment to investigate its relevance on two environmentally friendly initiatives, namely solar panels and eco-friendly transport. We found that some attitudes and behavioral intentions are subject to positive change when individuals are solicited a day when the weather is congruent with the proposed changes. We draw several policy and managerial implications for ecological issues.

National audience; I examine how incentives for refutation affect publication quality. I build a sequential model of public experimentation with two scientists, a researcher and a refuter. The researcher chooses when to publish a result confirming a hypothesis, with a probability that the result has type I error. The publication quality corresponds to the probability that the hypothesis is valid, which is the complement of the probability of type I error. Once the result is published, the refuter starts experimenting but, unlike the researcher, he can choose between working on refutation or on an outside safe option at any time. When scientists are initially pessimistic about the hypothesis' confirmation and when refutation is costly for the researcher, the higher the refutation rewards, the lower the equilibrium publication quality in case the researcher is more efficient than the refuter. The opposite result holds when the refuter is more efficient. In an extension, when the researcher's experimentation is private, I prove that the publication quality is lower than in the public experimentation case, suggesting that transparency improves research quality