The meaning of conversion in syllogistic reasoning

Abstract

While the construct of illicit conversion has been incorporated into most contemporary models of syllogistic reasoning, there has been some confusion in the literature as to the precise meaning of conversion. Two quite distinct formulations have appeared that can be characterized as conversion by addition and conversion by substitution. The present paper clarifies the differences between these two formulations and identifies specific syllogisms for which the two formulations generate different predictions. Data are presented that strongly support the conversion-by-addition formulation. © 1981, The psychonomic Society, Inc.. All rights reserved.