The three-stratum theory of cognitive abilities: Test of the structure of intelligence across the life span
Recently a three-stratum theory of intelligence that combines the major aspects of Spearman's (1927) theory of general intelligence (g) and Horn and Cattell's (1966) theory of crystallized and fluid intelligence (Gf-Gc) has been proposed (Carroll, 1993a). The purpose of this study was to test the three-stratum theory using hierarchical confirmatory factor analysis with the LISREL computer program. Developmental changes in the structure of intelligence were also investigated. Results provided support for the three-stratum theory and suggested the possibility of intermediate factors between the second and third strata but did not support developmental changes in the organization of cognitive abilities over the life span.