Cognitive Ability: Multiple Cognitive Abilities

Introduction

There are some theories supporting the view of intelligence as a collection of separate cognitive abilities (Gardner, 1993; Guilford and Hoepfner, 1971). Those theories follow the often-called ‘Thurstone tradition’ (Gustafsson, 1984). Guilford's Structure-of-Intellect (SOI) model postulates 180 separate abilities resulting from the combination of three cognitive facets: operations, contents, and products. Cattell's Gf-Gc theory distinguishes culture-reduced (Gf) and culture-specific (Gc) abilities (Cattell, 1987). Horn expanded Gf-Gc theory to include other abilities [Page 215]like Gv (visualization capacity), Gps (general perceptual speed), Gm (general memory capacity), and Gr (general retrieval capacity) (Horn, 1994). Although the Gf-Gc theory can be considered as a hierarchical model covering many domains of intelligence, it does not provide a higher order factor (g) to account for correlations among the identified (second-order) general cognitive abilities. Gardner's theory postulates several independent intelligences (spatial, musical, verbal, and so forth) (Gardner, 1993). Sternberg's triarchic theory distinguishes analytic, practical, and creative intelligence (Sternberg, 1985). What all these theories have in common is that group abilities are thought to be more prominent than the g factor.

However, it must be said at the outset that there is no conflict between group or specific cognitive abilities and g (Brody, 1992; Carroll, 1993; Jensen, 1998). Thurstone recognized that his primary cognitive abilities were correlated, admitting the possible existence of Spearman's general factor (g) at the second order of analysis. The Thurstone model is not really different from the Spearman model: there are group factors and a general cognitive ability (g). Guilford SOI abilities are in fact correlated: the near-zero correlations he found in his data were the result of sampling error, restriction of range, measurement error, and the inclusion of tests of divergent production (Carroll, 1993). When proper corrections are made for restriction of range and attenuation, all the correlations are above zero, with a mean of 0.45. Therefore, there is no empirical evidence in the SOI model that contradicts a hierarchical picture of intelligence with g at the apex: all cognitive tests are positively correlated (Colom & Andres-Pueyo, 2000; Jensen, 1998). Gustafsson suggested an expansion of Gf-Gc theory: the HILI model (Hierarchical Lisrel). The HILI model proposes that the g factor subsumes Gf, Gc and Gv. Moreover, g is supposed to be identical to Gf. Therefore, there is no contradiction between the Gf-Gc view of intelligence and g (Gustafsson, 1984).

Sternberg and Gardner cannot be included within this framework so easily, because they both go far beyond. This is what they usually claim, although one can have some reasonable reservations. First, the specific measurements of analytical, practical and creative abilities taken through the Sternberg Triarchic Abilities Test (STAT) correlate higher than 0.6. Correlations of this magnitude are telling a familiar story within the abilities domain: the positive manifold of the currently known measures. Second, there are some sample problems: university undergraduates or creative people are not the best samples to test the likelihood of the g factor (in addition to the non-questioned specific cognitive abilities). These samples represent the top 10% of the intelligence distribution in the entire population, and, therefore, there is a considerable restriction of range. Third, practical and creative intelligences in Sternberg's theory can be viewed as achievement variables reflecting how g is invested in activities as affected by opportunities, motivation, personality, and interests. The triarchic theory ‘itself is not the opposite of g, although separate abilities are considered more prominent in Sternberg's view of intelligence. Finally, Gardner's taxonomy is arbitrary and without empirical foundation. His view can have some interest in contexts like education, but there is nothing in the literature that gives an empirical foundation for Gardner's theory contradicting a hierarchical picture of intelligence with g at the apex.

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