Abstract

This study employed a 2×2×2 factorial design experiment, manipulating three factors to two levels each: the type of crime, the victim’s role, and the defendant’s likelihood of guilt. The study aimed to explore whether the lay person’s verdict and sentencing of a defendant, as well as their rating of the victim’s responsibility, are affected by legal factors. Data were obtained from 135 juror-eligible adults who voluntarily participated in the experiment, and were analyzed. The results showed that lay verdicts and sentencing decisions varied according to the defendant’s likelihood of guilt, and that confidence in the verdict was higher in sexual assault cases than in murder cases. Participants in sexual assault conditions tended to choose a higher sentence than those in murder conditions. In murder cases, the higher the defendant’s likelihood of guilt, the stronger the sentencing decision made by lay people. In contrast to the no-victim’s role conditions, the likelihood of the defendant’s guilt did not affect the victim’s responsibility rating in murder cases with a victim’s role, whereas a negative relationship between the two variables was found in sexual assault cases. The results suggested that lay people’s legal decisions are not aligned with the established legal framework. The authors discussed ways to improve the likelihood of jurors making reasonable legal decisions, as well as the necessity of refining the related system.