Action-Inaction Asymmetries in Moral Scenarios: Replication of the Omission Bias Examining Morality and Blame With Extensions Linking to Causality, Intent, and Regret

Omission bias is the preference for harm caused through omissions over harm caused through commissions. In a pre-registered experiment (N = 313), we successfully replicated an experiment from Spranca, Minsk, and Baron (1991), considered a classic demonstration of the omission bias, examining generalizability to a between-subject design with extensions examining causality, intent, and regret. Participants in the harm through commission condition(s) rated harm as more immoral and attributed higher responsibility compared to participants in the harm through omission condition (d = 0.45 to 0.47 and d = 0.40 to 0.53). An omission-commission asymmetry was also found for perceptions of causality and intent, in that commissions were attributed stronger action-outcome links and higher intentionality (d = 0.21 to 0.58). The effect for regret was opposite from the classic findings on the action-effect, with higher regret for inaction over action (d = −0.26 to −0.19). Overall, higher perceived causality and intent were associated with higher attributed immorality and responsibility, and with lower perceived regret.