Asking 'why?' enhances theory of mind when evaluating harm but not purity violations

Recent work in psychology and neuroscience has revealed important differences in the cognitive processes underlying judgments of harm and purity violations. In particular, research has demonstrated that whether a violation was committed intentionally vs accidentally has a larger impact on moral judgments of harm violations (e.g. assault) than purity violations (e.g. incest). Here, we manipulate the instructions provided to participants for a moral judgment task to further probe the boundary conditions of this intent effect. Specifically, we instructed participants undergoing functional magnetic resonance imaging to attend to either a violator's mental states (why they acted that way) or their low-level behavior (how they acted) before delivering moral judgments. Results revealed that task instructions enhanced rather than diminished differences between how harm and purity violations are processed in brain regions for mental state reasoning or theory of mind. In particular, activity in the right temporoparietal junction increased when participants were instructed to attend to why vs how a violator acted to a greater extent for harm than for purity violations. This result constrains the potential accounts of why intentions matter less for purity violations compared to harm violations and provide further insight into the differences between distinct moral norms.