Research

If individuals tend to behave like their reference group, is it because of peer effects, self-selection, or both? Using a peer effect model allowing for conformity and link formation, we designed a real-effort laboratory experiment in which individuals could misreport their performance and select their peers. Our results reveal both a preference for conformity and homophilous link formation, but only among individuals cheating in isolation. This suggests that such link formation was not motivated by a taste for similarity but by acquiring self-serving information.

How should a Designer protect a network that will be attacked by an Adversary? To answer this question, we introduce a strategic model where the Designer aims to build a cost-effective network with both protected and non-protected links, while the Adversary seeks to disrupt it. Our findings highlight that the Designer chooses either a minimal 1-link-connected network with protected links, or a (k + 1)-link-connected network with non-protected links, or a combination of one protected link and a specific number of non-protected links. We also explore scenarios with limited protection and imperfect defense, shedding light on preserving network integrity under challenging conditions.

Exploring network formation models, the Center-Sponsored Star (CSS) equilibrium, where one player connects to all others, faces challenges due to coordination failure and fairness concerns in real-life experiments. To address this, we introduced a sequential linking process and participant heterogeneity to examine its impact on network structures. The results revealed that sequential decision-making fosters fair and efficient networks, while the CSS equilibrium remains elusive. Additionally, the influence of heterogeneity varies; participants with higher values attract more links, resulting in increased network asymmetry, whereas non-monetary heterogeneity has no significant effect on linking decisions.

Quels processus de décision se cachent derrière les réalités sociales qui déterminent le fonctionnement de l’économie ? Comment définir les coûts et les bénéfices entre lesquels nous devons arbitrer ? Pourquoi même l’absence de choix est-elle une forme de décision ? Comment les décisions individuelles se combinent-elles avec les décisions collectives ? Quelle est la palette d’outils permettant d’orienter les comportements ?

L’économie comportementale apporte des réponses à ces questions en étudiant les décisions économiques à travers le prisme de facteurs rationnels, la comparaison des coûts et des bénéfices, mais aussi psychologiques, tels que les ressources cognitives, le contexte et le comportement des pairs.

Investigating decision-making rules for committees, simple majority rule is often considered optimal for handling numerous binary decisions, assuming sincere voting. However, our proposed algorithms reveal that logrolling agreements can impact this rule's effectiveness. Through experimental analysis, we find that logrolling improves unanimity rule's performance but may complicate matters for majority rule, raising questions about its superiority in the presence of logrolling. 

Rumors are opinions with unsure veracity that are spread in social networks, even by individuals who would prefer to only spread the truth. The presence of biased agents − who want to diffuse one particular opinion, true or not − influences the beliefs of unbiased agents. Thanks to an experiment, we investigate the effect of the structure of the network, the distribution of biased/unbiased agents, and the position in the network, on the diffusion of rumors. Our results show that unbiased participants have a tendency to transfer too many rumors, even in a very abstract setting.