Proceedings of the Annual Meeting of the Cognitive Science Society

The physical behavior of moving fluids is highly complex, yetpeople are able to interact with them in their everyday liveswith relative ease. To investigate how humans achieve thisremarkable ability, the present study extended the classicalwater-pouring problem (Schwartz & Black, 1999) to examinehow humans take into consideration physical properties of flu-ids (e.g., viscosity) and perceptual variables (e.g., volume) ina reasoning task. We found that humans do not rely on simplequalitative heuristics to reason about fluid dynamics. Instead,they rely on the perceived viscosity and fluid volume to makequantitative judgments. Computational results from a prob-abilistic simulation model can account for human sensitivityto hidden attributes, such as viscosity, and their performanceon the water-pouring task. In contrast, non-simulation mod-els based on statistical learning fail to fit human performance.The results in the present paper provide converging evidencesupporting mental simulation in physical reasoning, in addi-tion to developing a set of experimental conditions that rectifythe dissociation between explicit prediction and tacit judgmentthrough the use of mental simulation strategies.