Societies today face important challenges related to cooperation, which is needed among individuals who interact at a nonregular frequency. In this context, cooperation can be sustained if social norms push in this direction. We design an online experiment in which participants make strategic choices in an infinitely socially iterated prisoner’s dilemma. We examine the effects of inequality on social norms of cooperation and how norm compliance, in turn, affects cooperation. Inequality exists when two participants defect and cooperation gives equal payoffs in one treatment or keeps the unequal payoffs in the other. The results show that inequality weakens social norms by limiting first- and second-order normative beliefs about cooperation as well as descriptive beliefs about the other participants’ cooperation. Inequality reduces the likelihood of cooperation mainly driven by the change in social norms. Overall, the mere existence of inequality causes these changes, not specific behaviors, depending on the participants’ type.

We examine the effects of gain framing and loss framing on small, repetitive efforts with piece-rate payoffs in laboratory experiments. Theoretical predictions, arising from the anticipation of higher reference points under loss framing, suggest an increased effort in that context. However, our results do not support this hypothesis; in fact, a reverse effect is observed among a subset of participants. Our findings also indicate that loss framing tends to increase participants’ stress levels.

A widespread transition towards diets based on plant proteins as substitutes for animal proteins would contribute to food system sustainability. Such changes in consumer food choices can be fostered by public policy. We conducted a field experiment to test whether providing consumers with information regarding the negative consequences of meat consumption on the environment or health increases the substitution of animal-based proteins with plant-based proteins. The consumers had to make three meal selections online and consume the products at home, the first without exposure to information and the latter two after exposure to environmental or health information. One group of consumers served as the control and received no information. The results show that half of the consumers consumed meals with animal proteins in all three cases. Observational learning does not enhance the impact of the information intervention. However, for a sub-sample of consumers, environmental information increases the likelihood of consuming plant-based protein products. Overall, a short-term information policy does not appear to be sufficient for altering consumer behaviour regarding the consumption of animal proteins.

To increase the share of intermittent renewable energy in our production mix, occupants of buildings can be called upon to lower, anticipate or postpone their consumption according to the network balance. This article presents a small-scale field experiment aimed at introducing demand response in the workplace. We test the impact of load-shedding signals assorted with incentives on the energy consumption of workers in the tertiary sector. Two incentive schemes are tested, namely, an honorary contest and a monetary tournament. The results show a reduction in workers power demand during the load-shedding periods when the incentives are based on the honorary contest. In contrast, the monetary tournament where workers can win money according to their behavior seems to have no impact. The results also suggest that few workers can be responsible for a large part of energy consumption while the building is partially automatically controlled.

This article addresses the value of information that affects the ambiguity faced by a decision maker. Our analysis is applied to the case of a farmer whose production can be damaged by a pest attack with unknown probability, this damage being reduced if the farmer decides to use a pesticide. Early warning systems have precisely been implemented in many countries to help farmers avoid inappropriate decisions in terms of pesticide use. We investigate, both theoretically and experimentally, how farmers value these systems. We propose a two-state self-insurance model in which an α -MaxMin Expected Utility farmer may use pesticides that reduce the loss in the accident state while incurring a cost in both states. Her decision to self-insure or not depends on risk and ambiguity attitudes. We compile and compare the value of two types of information leading to a reduction of ambiguity and analyze their properties with respect to ambiguity attitude. Both types of information are valued positively if the farmer is ambiguity averse. We conduct a framed field experiment in which farmers and agricultural students have to decide whether or not to apply pesticides depending on risk, ambiguity and the associated monetary gains resulting from pesticide cost. The experimental findings support the theory. The average value of information among all participants is between €0.9/ha and €3.3/ha depending on the information gain.

Mastery is a psychological resource that is defined as the extent to which individuals perceive having control over important circumstances of their lives. Although mastery has been associated with various physical and psychological health outcomes, studies assessing its relationship with weight status and dietary behavior are lacking. The aim of this cross-sectional study was to assess the relationship between mastery and weight status, food intake, snacking, and eating disorder (ED) symptoms in the NutriNet-Santé cohort study. Mastery was measured with the Pearlin Mastery Scale (PMS) in 32,588 adults (77.45% female), the mean age was 50.04 (14.53) years. Height and weight were self-reported. Overall diet quality and food group consumption were evaluated with ≥3 self-reported 24-h dietary records (range: 3–27). Snacking was assessed with an ad-hoc question. ED symptoms were assessed with the Sick-Control-One-Fat-Food Questionnaire (SCOFF). Linear and logistic regression analyses were conducted to assess the relationship between mastery and weight status, food intake, snacking, and ED symptoms, controlling for sociodemographic and lifestyle characteristics. Females with a higher level of mastery were less likely to be underweight (OR: 0.88; 95%CI: 0.84, 0.93), overweight [OR: 0.94 (0.91, 0.97)], or obese [class I: OR: 0.86 (0.82, 0.90); class II: OR: 0.76 (0.71, 0.82); class III: OR: 0.77 (0.69, 0.86)]. Males with a higher level of mastery were less likely to be obese [class III: OR: 0.75 (0.57, 0.99)]. Mastery was associated with better diet quality overall, a higher consumption of fruit and vegetables, seafood, wholegrain foods, legumes, non-salted oleaginous fruits, and alcoholic beverages and with a lower consumption of meat and poultry, dairy products, sugary and fatty products, milk-based desserts, and sweetened beverages. Mastery was also associated with lower snacking frequency [OR: 0.89 (0.86, 0.91)] and less ED symptoms [OR: 0.73 (0.71, 0.75)]. As mastery was associated with favorable dietary behavior and weight status, targeting mastery might be a promising approach in promoting healthy behaviors. Clinical Trial Registry Number NCT03335644 at Clinicaltrials.gov.

Nutritional information via simplified labelling on products’ front of pack has become common in retail stores and is now concerning nowcollective catering. While numerous studies have investigated the effects of such information policies on consumers' decisions in shops, few studies have focused on choices made in collective catering. In such settings, consumers must compose a meal by combining dishes to be eaten during the same occasion. Each choice is then dependent of the selection of other foods, yielding a different decision problem as in a store where items are selected independently of one another. The aim of this study was to understand whether a nutritional labelling, (Nutri-Score®), modified the choices of consumers and more precisely modified the meal composition strategies - the associations between dishes made by consumers. A computerized menu composition task was designed, 371 participants were randomly redirected either to an interface displaying the Nutri-Score® of dishes, or to an interface showing the dishes without Nutri-Score®. Bayesian logistic regressions were used to explore dependency relationships between foods in presence or absence of Nutri-Score®. When considering dishes individually, no significant effects of the Nutri-Score® were observed, but significant effects of the Nutri-Score® on composition strategies could be observed. Two types of strategies seemed to emerge: homogeneous behaviors, where selected dishes had similar scores and, compensatory behaviors where selected dishes had contrasted scores. In conclusion, the effect of a nutritional labelling can have complex consequences on food decisions that extend beyond the selection of food items taken individually.

In this paper we compare the impact of a gain framing with a loss framing on a simple and repetitive task. Based on the expectation of higher reference points in the loss framing than in the gain framing, we expected to generate higher effort in the former. Instead, we find no evidence of loss framing effect on participants’ efforts over the experiment. Our results suggest that time pressure on a task kills the loss framing effect. However, experimental sessions without time pressure confirm that the potential effect of loss framing as a nudge is minimal in our context. Nowadays where nudges seem to be the king way for changing behavior we find that monetary incentives are still very powerful to incentive behaviour especially with students.

We investigate whether risk, time, environmental, and social preferences affect single family homeowners’ investments in energy efficient renovations and energy quality of their house using established experimental measures and questionnaires. We find that homeowners who report to be more risk taking are more likely to have renovated their house. Pro-environmental and future-oriented renovators, i.e. renovators with lower discount factors, live in homes with higher energy efficiency. Controlling for the energy efficiency of houses, we further find that energy consumption as measured by heating and energy costs are lower for future-oriented and pro-environmental individuals. Social preferences measured in a dictator and a generosity game play a mixed role for investments in energy efficiency and energy consumption.

L'économie expérimentale est de plus en plus utilisée en économie agricole. Cet article rend compte d'une École Chercheurs organisée en 2015 par le Département SAE2 (Sciences Sociales, Agriculture et Alimentation, Espace et Environnement) de l'INRA afin de faire un état des lieux des travaux employant cette méthode et de discuter de son apport à l'économie agricole. Les auteurs examinent les défis méthodologiques comme les incitations monétaires et le biais hypothétique, les validités interne et externe ainsi que l'utilisation de la tromperie en lien avec les spécificités de la recherche en économie agricole, puis la portée académique et sociétale de travaux expérimentaux. Encore jeune dans ce champ, l'économie expérimentale ouvre la voie à des questions de recherche prometteuses.

Individuals rarely achieve investment activities characterised by up-front costs and delayed benefits. Point-of-decision prompts (PDPs) provide information about a better alternative or a deterrent to the behavioural standard at the moment the decision is made and may affect behaviour by helping individuals perform this type of investment activities. We conducted a field experiment to assess the effects of a PDP intervention that encourages taking the stairs rather than the escalator in three Paris (France) Metro stations for eight weeks from April to July 2014. In total, we followed up 205 individuals and the data show that PDPs have an immediate, albeit decaying, peaked effect on individuals' stair use, with a stronger effect when weak physical effort is made salient. However, the intervention did not change individuals’ stair-use habits. In the best-case scenario, the effects last two weeks after the intervention ends. Our preferred explanation is that PDPs act as “cues” but people become accustomed to them and in the end no longer notice them. These findings suggest that a PDP intervention is not sufficient to modify individuals investment in activities with immediate costs and delayed benefits in the long-run.

For most consumers, Corporate Social Responsibility is a credence attribute of products, which can be signaled either through a label certified by a third party, or via unsubstantiated claims used as part of a brand-building strategy. These claims may, in theory, be regulated by reputation mechanisms and the awareness of NGOs and activists. We use an experimental posted-offer market with sellers and buyers to compare the impact of these signaling strategies on market efficiency. Both third-party certification and the possibility of CSRrelated brand building give rise to a separating equilibrium. However, only third-party certification clearly produces efficiency gains, by increasing CSR investments. In markets where reputation matters little, unsubstantiated claims can generate a ‘halo’ effect on consumers, whereby the latter are nudged into paying more for the same level of CSR investments by firms.