A three-factor model of syllogistic reasoning: The study of isolable stages

Computer models of the syllogistic reasoning process are constructed. The models are used to determine the influence of three factors—the misinterpretation of the premises, the limited capacity of working memory, and the operation of the deductive strategy—on subjects’ behavior. Evidence from Experiments 1, 2, and 3 suggests that all three factors play important roles in the production of errors when “possibly true” and “necessarily false” are the two response categories. This conclusion does not agree with earlier analyses that had singled out one particular factor as crucial. Evidence from Experiment 4 suggests that the influence of the first two factors remains strong when “necessarily true” is used as an additional response category. However, the third factor appears to interact with task demands. Some concluding analyses suggest that the models offer alternative explanations for certain well established results.