Moral Reasoning as Probability Reasoning

Previous studies found that the likelihood of subjects to choose a deontological judgment (e.g., allowing harm) or a consequentialist judgment (e.g., doing harm) varied across different moral dilemmas. The present paper explored if the variation can be explained by the differentiation of the perceived outcome probabilities. We generated moral dilemmas that were similar to the classical trolley and footbridge dilemmas, and investigated the extent to which subjects were sensitive to the outcome probabilities. Results indicated that the majority of subjects, including both those who initially chose a deontological decision and those who initially chose a consequentialist decision could be sensitive to outcome probabilities. The likelihood of being sensitive to the probabilities was invariant across different dilemmas. The variation of the choice behaviors across different dilemmas might be associated with the variation of the estimated outcome probabilities.