Probability, measurement mismatches, and sacrificial moral decision-making

Despite the importance of uncertainty in decision-making, few published studies have examined how individuals make moral judgments under uncertainty. Across four experiments (N = 445), we examined whether a relatively small shift in probability affected participants' judgments of both moral acceptability and choice. Overall, reading dilemmas where the characters were either certain or likely to die, the probability of the sacrificed individual and the group at risk dying both had independent effects on participants' responses. That is, participants were more accepting of sacrificing the individual if they were not certain to die, but less accepting if the group was only likely to die when the individual was not sacrificed. Furthermore, a number of participants made acceptability ratings that did not match the action they endorsed, either finding the sacrificial decision more acceptable but refusing to make it, or choosing the sacrificial decision while viewing it as less acceptable. Many participants also stated that this was because they recognised a crucial difference between what they viewed as morally acceptable in a dilemma and what they were actually willing to do. Such mismatches may reflect the sensitivity and complexity of the moral principles that individuals employ during their moral decision-making.