Refusal of Killing a Stranger to Save Five Brothers: How Are Others’ Judgments Anticipated and Favored in a Moral Dilemma Situation?

Abstract

One evolutionary theory of morality, examined here, is based on theories of kin selection while another has proposed that moral judgment is based on a Kantian rule-based system. Using the Trolley Problem, Kurzban et al. (2012) asked subjects to decide whether they would kill one person to save five others, varying the relationship of the subject with the others involved. They revealed that nearly half of the subjects reported that they would be unwilling to push one stranger to his/her death to save five brothers in a footbridge version of the Trolley Problem. In the present study, I tried to replicate this somewhat surprising result in Japanese participants, to investigate the robustness of the finding. I also examined how participants anticipated and favored the moral judgment of other people. If a Kantian decision was made according to the coordination system suggested by Kurzban et al. (2012), a Kantian decision, rather than a Hamiltonian decision, would be anticipated and favored as the decision of people generally. The results seem to support the discussion of Kurzban et al. (2012), that the computational system that delivers Kantian moral judgment functions to coordinate condemnation decisions.