This study investigated the effect of moral foundation and feeling of disgust toward a
criminal case on non-professional legal decisions. Three hundred and sixty participants
were asked to read a fictional story about a murder attempt case and rated a possi-
bility that a defendant, who had denied all charges against the case, would be judged
as guilty. Participants were also rated a degree of regrets about their decision if the
truth would be either guilty or not guilty. The degree of physical injury of a victim was
varied in accordance with three conditions (i.e., minor, heavy, and permanent damage).
The analysis revealed that participants who put much value on not harming others felt
disgust toward the criminal case, and that resulted in higher ratings of possibility that
the defendant would be judged as guilty. In addition to that, as the degree of physi-
cal injury of the victim got severer, the ratings of the possibility also got higher, and
participants felt less regrets of their decision even if the defendant was actually not
a real perpetrator and thus they made Type II error. We discussed characteristics of
non-professional legal decisions from both theoretical and practical perspectives.