Integrating concepts and tests of intelligence from the differential and developmental traditions

This study aimed to test a possible convergence in the structure of cognitive abilities as specified by classic psychometric theory and two neo-Piagetian theories of cognitive development, namely the theories of Case and Demetriou. A large test battery was constructed which contained items from the WISC-Rc, from Case's and from Demetriou's previous research. The battery comprised five subscales that were intended to assess spatial, quantitative, verbal/propositional, qualitative/analytic (categorical), and causal thought. It was given to 120 7- to 10-year-old children. Exploratory factor analysis uncovered five factors, which were interpreted as representing spatial, quantitative, social/verbal, logical/analytic, and causal thought. These same five factors emerged when the analysis was rerun on the age-partialled correlation matrix. Confirmatory factor analysis validated this structure and also indicated that a general factor was needed to account for performance on the battery as a whole. The relative contribution of the general and specific factors for each task was determined using the Schmid-Leiman method of orthogonalization for hierarchical factors. The results were interpreted to suggest that Demetriou's theory of specialized capacity spheres, Case's theory of central conceptual structures (CCSs), and the classic psychometric notion of hierarchically nested general and specific abilities can be integrated into a comprehensive system. A brief outline of such a system was presented, and its possible merits outlined. (C) 2001 Elsevier Science Inc. All rights reserved.