Propositional reasoning by mental models? Simple to refute in principle and in practice.

Two experiments compared the predictions of mental-models theory with a mental-logic theory. Results show that people do not make fallacious inferences predicted by mental-models theory but not predicted by mental-logic theory and that people routinely make many valid inferences predicted by mental-logic theory that should be too difficult on mental-models theory. Thus, the mental-logic theory accounts better for the data. A difference between the two theories concerning predictions about the order in which inferences are made was also investigated. The data clearly favor the mental-logic theory. It is argued that the mental-logic theory provides the more plausible description of the actual psychological processes in propositional reasoning.