Sébastien Massoni, Professeur d'Economie, Université de Lorraine

Le séminaire de recherche du jeudi 12 novembre 2026 est animé par Sébastien Massoni, Professeur d'Economie à l'Université de Lorraine et Chercheur au Bureau d’Economie Théorique et Appliquée, BETA.
 

Ses thèmes de recherche :

• Experimental and Behavioral Economics,

• Cognitive Science,

• Decision Theory,

• Law and Economics,

• Applied Public Economics,

• Clustering and Classification.

Titre de sa présentation : Guilty Beyond Reasonable Doubt? Measuring How Jurors Translate Uncertainty into Verdicts

Résumé : How do jurors translate uncertain evidence into conviction beyond reasonable doubt? We study this question in a two-stage online experiment designed to separate wrongdoing from evidence evaluation. In Stage 1, participants earn income and may steal from a matched victim; a loss may also occur mechanically, creating uncertainty about whether the defendant is truly guilty. In Stage 2, independent jurors observe informative but imperfect signals with known precision and decide whether to convict. We elicit prior beliefs, posterior beliefs, and verdicts, and use switching behavior across different levels of evidence to identify individual conviction thresholds as a behavioral measure of reasonable doubt. We also elicit willingness to pay to correct wrongful verdicts and to implement justice-consistent outcomes from a status quo. Our results show that jurors respond strongly to the precision of incriminating evidence, while prior beliefs also influence conviction decisions. Willingness-to-pay measures reveal significant asymmetries: participants are willing to pay more to correct wrongful acquittals than wrongful convictions, and to convict guilty defendants than to acquit innocent ones from a neutral status quo. Our findings illustrate how reasonable doubt can be measured through incentivized decisions and reveal that substantial heterogeneity in conviction thresholds remains largely unexplained by elicited preferences and individual characteristics.

 
Le séminaire a lieu à 11h15, au GAEL