We investigate how learning that an established type-level causal relationship is implemented by human agency affects people’s conceptualization of this relationship. In particular, we ask under what conditions subjects continue to perceive the original root cause as appropriate explanation for the resulting effect, and under what conditions they perceive the mediating intentional action as alternative explanation instead. Using a new experimental paradigm, we demonstrate that mechanisms involving intentional action lead to intuitions of causal intransitivity, but only when these actions are norm-violating. Potential generalizations and implications for scientific theory construction are discussed.

When A causes B and B causes C, under what conditions isA a good explanation for the occurrence of C? We proposethat distal causes are only perceived to be explanatory if thecausal mechanism is insensitive to inessential variations ofboundary conditions. In two experiments, subjects first ob-served deterministic A → B → C relationships in a single ex-emplar of an unknown kind. They judged A to be crucial forC by default. However, when they subsequently learned thatthe causal mechanism fails to generate the A → C dependencyin other exemplars of the same kind, subjects devalued A asa crucial explanation for C even within the first exemplar. Werelate these findings to the idea that good explanations pick outportable dependency relations, and that sensitive causes fail tomeet this requirement.