Logical Necessity in Class Inclusion Development and the Ability to Process Transformations

Abstract

The use of Markman’s modification task in the study of class inclusion development revealed a developmental gap between the ability to compare the extensions of classes and subclasses and the understanding that the superiority of the class extension is a logical necessity. Barrouillet and Poirier (1997) have proposed that the main difficulty in Markman’s task lies in its demand for the processing of transformations. Indeed, necessity arises from the impossibility of transforming facts. The present study explores this hypothesis by comparing children’s performances on a task of logical necessity and a task that requires them to process transformations of class extension. The results, consistent with Barrouillet and Poirier’s view, are discussed with reference to Piaget’s morphism theory and Halford’s relational complexity theory.