Raymond Cattell, in 1963 introduced two types of cognitive abilities in a revision of
Spearman's G factor concept of general intelligence: fluid intelligence (Gf) and
crystallized intelligence (Gc). Fluid intelligence is the mental ability to solve novel
problems (like number series and figure classifications) by using abstract reasoning
and flexible thinking and depends minimally on prior learning and education.
Crystallized intelligence (Gc) is the ability to solve problems (like word analogies and
word similarities) by using learned methods and knowledge and depends strongly on
prior learning, experience, knowledge, and education. The concepts of Gf and Gc were
later further developed by Cattell and his former student John Horn.
John Carroll, in 1993 proposed the three-stratum theory, which is a hierarchical model with three layers (strata). The bottom level consists of narrow abilities that are taskspecific (e.g., induction, spelling ability), a few broad factors at the intermediate level, which are fluid intelligence (Gf), crystallized intelligence (Gc), general memory and learning (Gy), broad visual perception (Gv), broad auditory perception (Gu), broad retrieval ability (Gr), broad cognitive speediness (Gs), and processing speed (Gt), and at the top a single factor, the g factor, which accounts for the correlations among all cognitive tasks. The three-stratum theory is an expansion of Spearman's model of general intelligence and Horn and Cattell’s model of fluid and crystallized intelligence.
John Carroll, in 1993 proposed the three-stratum theory, which is a hierarchical model with three layers (strata). The bottom level consists of narrow abilities that are taskspecific (e.g., induction, spelling ability), a few broad factors at the intermediate level, which are fluid intelligence (Gf), crystallized intelligence (Gc), general memory and learning (Gy), broad visual perception (Gv), broad auditory perception (Gu), broad retrieval ability (Gr), broad cognitive speediness (Gs), and processing speed (Gt), and at the top a single factor, the g factor, which accounts for the correlations among all cognitive tasks. The three-stratum theory is an expansion of Spearman's model of general intelligence and Horn and Cattell’s model of fluid and crystallized intelligence.
The Cattell–Horn–Carroll theory integrates the Gf-Gc model of fluid and crystallized
intelligence with John Carroll’s three-stratum intelligence model. Due to similarities
with the latter, the two theories were merged to form the CHC model. The broad
abilities of the Cattell–Horn–Carroll theory are fluid reasoning (Gf), comprehensionknowledge (Gc), quantitative knowledge (Gq), reading and writing abilities (Grw),
short-term memory (Gsm), long-term storage and retrieval (Glr), visual processing
(Gv), auditory processing (Ga), processing speed (Gs), decision/reaction time/speed
(Gt), General (Domain-Specific) Knowledge (Gkn), Psychomotor abilities (Gp),
Psychomotor speed (Gps), Tactile Abilities (Gh), Kinesthetic Abilities (Gk), and
Olfactory Abilities (Go). The Cattell-Horn-Carroll (CHC) theory of cognitive abilities is
considered by modern psychometricians as the most comprehensive and empirically
supported psychometric theory of the structure of cognitive abilities.