A comparison of sentencing decisions and their justification between professional judges and laypeople in Japan

Few experimental attempts have been reported comparing the sentencing decisions of professional judges and that of laypeople using the same criminal case. This study examined the sentencing justifications (retribution, incapacitation, general deterrence, and rehabilitation) and the resulting imprisonment sentencing differences between Japanese judges and laypeople. The online quasi-experiment comprised 48 judges and 199 laypeople. Participants read a fictional murder case, and they were asked to respond on two types of justification scales and enter the number of years of imprisonment for the offender. Both the judges and laypeople placed the highest importance on retribution in the numerical input scale, which failed to detect the difference. The Likert scale revealed that judges add less weight to rehabilitation, incapacitation, or general deterrence, than laypeople. As predicted, the number of imprisonment years chosen by judges was significantly shorter than that of laypeople. The differences in justification can cause disagreements between judges and laypeople. This study suggests that judges do not give much consideration to justifications and decide on sentencing based on different criteria than laypeople. Differences from previous studies related to the judges’ emphasis on justification and the disparity of sentences are also discussed.