Society Versus Jury: A Case for Limiting Behavior

We model a simple justice system in which a jury is mandated by society to assess the guilt and the punishment of an accused. Jurors are assumed to be almost perfect representatives of society, but they ignore the cost to society of implementing the sentence. As a result the jury is shown to condemn more often and to higher penalties than society would find it optimal. We show that imposing upper and lower limits to penalties helps to align the jury's objective with society's.