Learning by doing… or watching doing. How do criminals learn the criminal law?

How does punishments affect offenders’ understanding of criminal law? This paper uses a natural experiment in France in which sentences were increased by 3.5 months of prison (+67%) and 4 months of probation (+285%) for a specific type of recidivism: new crimes similar to previous ones. Using a difference in difference setting, it shows that offenders convicted under the new law committed slightly fewer crimes in the 6 years after the trial. This general effect hides a strategic reaction. Even if all offenders could be harshly sentenced under the law, those who experienced it significantly decreased their probability of committing a new crime similar to previous ones – the behavior that is targeted by the law – but did not change their probability of committing other crimes. This difference between similar and different new crimes is only observed among offenders who attend their trial and get their sentence explained. These results are consistent with a strategic reaction to the reform based on a better understanding of criminal law. This better understanding of the criminal law spread to targeted offenders’ criminal partners. Offenders who did not experienced the reform but saw it applied to peers tend to strategically react to it.