Category-based induction: an effect of conclusion typicality.

Category-based induction involves the willingness of a thinker to project some newly learned property of one or more classes of objects to another class on the basis of their shared membership in a common superordinate category. Previous research has established that the perceived strength of arguments of the form "Class A has Property P; therefore, Class B has Property P" is influenced by the similarity of A to B and by the typicality or representativeness of A in a shared category, superordinate to both A and B. (The nature of P is also crucial, but we do not examine it in this study.) There is, however, no prior evidence that the relation between B and the category is influential. Three experiments were designed to test whether the typicality of B in the superordinate category also has an effect on inductive argument strength. By using multiple regression (Experiment 1) and an experimental design (Experiment 3), an effect of conclusion typicality was found, so that people are more willing to project properties to more typical conclusions. Experiment 2 ruled out conclusion familiarity as a potential confounding variable. The results are interpreted in the light of current models of category-based induction.