Research

Inequality, Social Norms and Cooperation: Strategy Choice in the Infinitely Repeated Prisoners' Dilemma

Teyssier, S., & Wieczorek, B. (2025). Inequality, social norms and cooperation: Strategy choice in the infinitely socially iterated prisoner’s dilemma. Journal of Economic Behavior & Organization, 229, 106819.

​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.  

Social Norms and Community Enforcement of Cooperation

Teyssier S, Wieczorek B. - To be submitted.

Dynamic information provision for household water consumption

Wieczorek B. - Submitted.

​Evidence of the effectiveness of social norms information in increasing pro-social and pro-environmental behavior has been widely reported in the literature and by policy-makers. Static information on social norms has proved effective in influencing marginalized individuals in the areas of water, energy, and others.

In this study, I developed a field experiment on household water consumption by implementing a new information policy based on the literature on dynamic norms to influence average individuals, who represent the majority. Dynamic information exploits the spread of pro-social or pro-environmental behaviors in order to promote them.

Results show a significant effect of dynamic information on below-average households, with a reduction of over 20\% of water consumption. Yet their effectiveness disappears over time, suggesting their potential is fully exploited on specific occasions, such as a temporary drought. Finally, I explore explanations for the effectiveness or ineffectiveness of the different information provided by cognitive and psychological processes.

Proenvironmental behavior dynamics in polarized populations 

Wieczorek B., Ferrière R. - To be submitted.

​In the face of global environmental challenges, proenvironmental action is hampered by multiple social and behavioral obstacles, resulting in exceedingly slow societal moves. Identifying and evaluating these obstacles, and designing robust pathways to behavioral change, is difficult because of the complexity of the factors involved and their interactions in polarized populations. Mathematical models can help decipher the complexity of interacting processes, delineate feasible goals, and highlight targets to facilitate transitions.

Here we develop a behavior-environment feedback model to evaluate the roles that key individual, social, and environmental factors play in promoting or hindering behavioral change in polarized populations. Specifically, we ask how individual attitudes, descriptive and normative expectations, and environmental experience influence the adoption of a costly proenvironmental behavior. We contrast two main situations -- whether individuals with a proenvironmental attitude represent a minority or make the majority of the population. 

The model successfully captures the challenge: Even a strong proenvironmental attitude may not be sufficient to allow a minority of the population to express their behavioral preference in their own group; moreover, even if the population is composed of a majority of proenvironmental attitudes among which the active behavior spreads, this may not be sufficient for the proenvironmental behavior to be adopted in the rest of the population. For the widespread adoption of the active behavior, fixed gains influenced by non-material payoffs and attitude strength, together with the degree of individual focus in forming descriptive and normative expectations, are key. While the components of our model can be set up to characterize a population of interest and its transition trajectory toward a steady state within a given system, public policy interventions have the capacity to modify these elements, thereby altering the system's predictive outcomes with deterministic consequences. For its part, the role of the environmental experience is decisive but subtle, as a small but non negligible dose of environmental feedback is necessary for the propagation of the costly proenvironmental behavior. Given the complexity of achieving global adoption of pro-environmental actions, as observed in current societal trends, our findings emphasize the crucial role of environmental policies in promoting widespread efforts to mitigate climate change in polarized populations, emphasizing their relative effectiveness according to the distribution of the polarized population.

Social Tipping Condition on Coordination Games

Tavoni A., Wieczorek B.

​Effective climate change mitigation to avert catastrophic consequences requires a rapid and widespread transition from existing societal and economic baselines to more sustainable and virtuous equilibria. Despite the identification of multiple pathways, large-scale global transitions have yet to materialize.

To investigate the role of human biases in shaping these transitions, we develop an experimental framework capturing both the endogenous emergence of an initial equilibrium and its transition toward a more efficient one. This study focuses on the most fundamental cases, coordination scenarios wherein individual interests align toward a shared objective, investigating the impact of group size and payoff structures, weighing either mainly on pairwise or group coordination. While utility maximization of earnings predicts equivalent coordination and transition behaviors across treatments, we examine the role of social norms and individual behavior as mechanisms moderating our experimental condition.

Increasing group size negatively impacts transitions through two converging mechanisms. First, it inhibits the early emergence of shared norms, thereby weakening initial group coordination, which restricts transitions. Second, it exerts an additional direct negative effect on transitions. Modifying the payoff structure toward pairwise coordination negatively impacts transitions through two diverging mechanisms. First, it alters individual coordination behavior, thereby enhancing initial coordination, which facilitates transitions. However, a second direct negative impact on transitions counteracts this effect. Finally, combining the two conditions produces an additional direct positive effect on transitions, without altering the abovementioned mechanisms. Our study highlights the pivotal influence of interaction and community characteristics on transition dynamics, offering insights into environmental policies.

Social Tipping Interventions on Coordination Games

Berger J., Tavoni A., Wieczorek B. 

Sharing Energy Resources

Llerena D., Roussillon B., Rouchouze O., Pizziol V., Wieczorek B., Fadhuile A., et al.

Complementarity and Agency in Shaping Environmental Action

Pizziol V., Wieczorek B.