The Effect of Moral Judgment on Bystander Cooperation Behavior: The Role of Personal Force

Background: While extensive research has examined the antecedents of utilitarian moral judgment, its subsequent social consequences remain less explored. Drawing on the moral reciprocal partner selection model and the moral intuition modular myopia hypothesis, this study investigates the impact of utilitarian moral judgment on bystander cooperation behavior and the moderating role of personal force. Objectives: This research aims to determine whether utilitarian moral judgments, compared to non-utilitarian ones, decrease bystander cooperation (Hypothesis 1), and whether this effect is more pronounced when the utilitarian judgment involves personal force (Hypothesis 2). Methods: Two progressive between-subjects experiments were conducted. Experiment 1 (N = 159) employed a single-factor design (utilitarian vs. non-utilitarian judgment) using a footbridge dilemma scenario and a trust task to measure cooperation. Experiment 2 (N = 346) utilized a 2 (judgment: utilitarian vs. non-utilitarian) × 2 (personal force: personal force vs. no personal force) factorial design, employing the same trust task. Results: In Experiment 1, bystanders invested significantly fewer tokens in the trust task after observing a utilitarian judgment compared to a non-utilitarian one. Experiment 2 revealed a significant main effect of moral judgment and a significant interaction between moral judgment and personal force. Simple effects analysis confirmed that the negative effect of utilitarian judgments on cooperation was stronger when personal force was involved. Conclusions: Utilitarian moral judgments reduce bystander cooperation compared to non-utilitarian judgments, and this reduction is more substantial when the judgment involves personal force. These findings highlight the interpersonal costs of utilitarian decision-making and underscore the importance of contextual features like personal force in understanding its social reception.