Proceedings of the Annual Meeting of the Cognitive Science Society

A causal illusion occurs when people perceive a causal relationship between two events that are not contingent on each other. This experiment explored how this illusion varies when people reason diagnostically (i.e., in an effect-to-cause direction). Participants learnt about an illusory cause-effect relationship in which the probability of the cause and the probability of the effect were orthogonally manipulated to be either high or low. Participants learnt either predictively (i.e., cause-to-effect) or diagnostically, and at test had to make two causal judgements that encouraged either predictive (cause-to-effect) or diagnostic (effect-to-cause) reasoning. Diagnostic reasoning at test increased the strength of the cause density bias and decreased the strength of the effect density bias. It also decreased causal ratings, but only after predictive learning. Explaining these results requires an understanding of how the process of causal learning can impact later reasoning; something the current literature is yet to provide.