The role of mental simulation in judgments of likelihood

This research examined how people simulate causal scenarios. Several factors affect the perceived likelihood of a given causal scenario. In particular, generating one, several, or multiple causal scenarios affects the perceived probability of the focal causal scenario. In experiment 1, the perceived likelihood of the focal causal scenario was affected by the number of causal scenarios the participant constructed. Experiment 2 manipulated the likelihood of the scenarios the participants constructed; the judged probability of the focal causal scenario was affected by the likelihood of the scenarios constructed by the participants. The results of both experiments suggest that participants use several scenario-evaluation mechanisms to ''prune'' the set of causal scenarios under consideration. These mechanisms involve consistency checking and searching for leading contenders. (C) 1997 Academic Press.