Alessandro Ispano, Université de Cergy-Pontoise

"A model of interrogations"

Abstract

We provide a model of interrogations in which both the suspect and the police have private information. The suspect's type determines his status as innocent or guilty as well as the strength of the evidence the police is likely to hold against him. The police's evidence provides information about the suspect's type directly and also makes the suspect's claims, if any, partially verifiable. Equilibrium communication exhibits several natural features: sufficiently unsuspicious guilty types lie; lying is costly due to the chance of being disproved; bigger lies are more likely to be disproved but also more credible when not disproved. We use the model to study if, how and when the police should reveal her private information to the suspect to maximize the probability of (honest) admission of guilt. One-shot partial revelation is typically beneficial and implementable by means of simple laws already in place in many legal systems. It may be further improved upon by gradual information revelation if leniency can depend on the time of confession. Our results offer new insights on widely adopted legal institutions such as requirements for questioning, disclosure duties, the right to silence and adversarial inferences.

(Joint work with Peter Vida)

Contact person: Egor Starkov