Carrolls Three Stratum Model

Aside from the specification of the 9 to 10 broad ability Cattell-Horn model, the most important influence in applied intelligence testing during the past decade has been Carroll's (1993) meta-analysis integration of the extant psychometric factor-analytic research (see Figure 14.1). Briefly, Carroll retrieved, sampled, and then factor-analyzed (via exploratory "let the data speak for themselves" methods) the reported correlation coefficients or raw data from 461 post-1925 data sets, including four sets drawn from the 1977 WJ norming sample. Carroll (1993, 1997) articulated a hierarchical three-stratum theory. Sixty-nine specific, or narrow, abilities were identified and classified as Stratum I abilities. The narrow abilities were subsumed under broad categories of cognitive ability (Stratum II), which he labeled 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). At the apex of his model (Stratum III), Carroll identified a higher-order factor above the broad factors, which he interpreted as General Intelligence, or g.

Notwithstanding the differences between the Cattell-Horn and Carroll models, the two models are very similar. Carroll (1993) reached the same conclusion when, after reviewing all the major theories of intelligence, he described the Gf-Gc model as the best available model of the structure of human intellect:

The Cattell-Horn model, as summarized by Horn

(1985, 1988), is a true hierarchical model covering all major domains of intellectual functioning. Numerous

Structural, developmental, genetic, outcome, and neurocognitive evidence led to and supports...

Carroll's (1993) synthesis of the extant factor analysis research on cognitive abilities led to.

Understanding And Treating Autism

Understanding And Treating Autism

Whenever a doctor informs the parents that their child is suffering with Autism, the first & foremost question that is thrown over him is - How did it happen? How did my child get this disease? Well, there is no definite answer to what are the exact causes of Autism.

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