Comparison Then Computation: A Model of Independent Causal Efficacy

This paper introduces the Comparison Then Computation (CTC) model, which describes how individuals assess the causal efficacy of a target event when simultaneously learning of multiple potential causes of the same outcome. The CTC is a two step model that entails an initial comparison between the probability of an outcome given the target alone and that given the joint occurrence of the target and other explicitly represented alternatives. The first step determines the computation to be performed in the second step. This computation heavily weights sufficiency information over necessity information. Two experiments testing novel predictions of the CTC model favored that model over causal power (Cheng, 1997) and weighted averaging (White, 2008). Strengths and weaknesses of the CTC model will be discussed.