2019 年 17 巻 2 号 p. 147-152
The present study examined whether people's beliefs in free will affect their moral and judicial judgment. Specifically, using a survey method, we examined the mediation by moral judgment which has been theoretically discussed and illustrated in a previous research. In addition, this study focused on the role of explicit motives toward retribution and incapacitation and examined the hypothesis that people whose beliefs in free will were low would focus on incapacitation. An online survey was conducted, and 232 participants were analyzed (96 females, M age = 20.75, SD = 2.46). Participants answered their own free will belief and then read a fictitious scenario about manslaughter case. They answered to what extent they were motivated toward retribution and incapacitation and made moral judgment and judgment of sentencing. A mediational analysis revealed that the process was significant (β = .18, 95 % CI = [.11, .25]). However, no correlations between free will belief and explicit motives were observed (rs = –.11 and .01). Also, retributive motive had no correlation with moral judgment and sentencing (rs = –.08 and .01), while the motive toward incapacitation correlated with both (rs = .26 and .21). Two statistical models explaining how free will belief and the motive toward incapacitation affect sentencing were constructed. One supposed moral judgment mediated the effects of free will belief and incapacitation (i.e., full-mediation model). The other model supposed another direct path from incapacitation to sentencing (i.e., partial-mediation model). As a result, full-mediation model was adopted in terms of model fit (BIC = –10.91 vs. –8.52) and coefficients of determination (R2 = .20 vs .21). The importance of free will belief in people’s daily lives and future directions of researches were discussed.