Previous studies have found that the proportions of people who endorsed utilitarian decisions varied across different variants of the trolley dilemma. In this paper, we explored whether moral choices were associated with beliefs about outcome probabilities in different moral dilemmas. Results of two experiments showed that participants’ perceptions of outcome probabilities were different between two dilemmas that were similar to the classical switch case and footbridge case. Participants’ judgments of the outcome probabilities were associated with their moral choices. The results suggested that participants might not accept task instructions and thus did not perceive the outcomes in the dilemmas as certain. We argued that researchers who endorse descriptive tasks in moral reasoning research should be cautious about the findings and should take participants’ beliefs in the outcomes into account.
