The "equal punishment for the same crime" principle is generally agreed upon--yet its implementation differs radically depending on whether the punishment is measured purely in nominal terms or whether the subjective perspective of the punishee is accounted for. This is simply because different people may experience the same punishment with differing intensity.

Legal scholars have recently proposed that improvements in scientific knowledge and advancements in technologies (such as Functional magnetic resonance imaging), which allow us to measure subjective perceptions and feelings, need to be and should be incorporated in our penal systems. This would facilitate calibrating the punishment not only to the crime but also to the offender's persona, so that different people experience equally tough punishment for the same crime.

However, such a substantial change in criminal law and policy necessitates a certain amount of public legitimacy and understanding among constituents. We ran a simple experiment in order to learn how people understand punishment and to ascertain whether such legitimacy exists.

We find such a legitimacy may exist in the case of pecuniary punishments. With regard to incarceration policies, however, the likelihood of popular acceptance ofproposed innovations is rather remote. Our findings therefore point out a serious challenge for the scholarship favoring the subjective approach to punishment and may complicate the implementation of suggested reforms, even if legal scholars find them worthwhile.