John B. Carroll’s Three Layers of Intelligence Theory proposes that the factor structure of human cognitive skills be composed of a general intellectual capacity (the g factor), a set of 8 general skills, such as speed of mental processing or memory, and a third layer which would include more specific intellectual skills and depend on one of the above.
In this article, we will analyze Carroll’s model, which today is often studied and applied in conjunction with the theory of fluid and crystallized intelligences proposed by Cattell and Horn. We will focus particularly on the analysis of each of the layers of intelligence that have been described by this author.
John Carroll’s theory of intelligence
The American psychologist John Bissell Carroll (1916-2003) is best known for his contributions in the field of psychometry around the measurement of phenomena such as intelligence, language skills or academic performance. On the other hand, his theoretical approaches to cognition and language are also very relevant.
Of particular note is his theory of three strata, 1 model based on the results of hundreds of factor analyzes on numerical data samples that can serve as predictors of intelligence, such as IQ tests or marks obtained in academic assessment tests.
Carroll presented the results of his studies as well as his theory of intelligence in the work entitled “Human Cognitive Abilities: An Investigation of Analytical-Factorial Studies”, which was published in 1993. In this book, he highlighted the distinction between skills related to individual differences. and those arising from the quality of education.
Currently, Carroll’s theory of the three strata is considered to be complementary to the model of Raymond B. Cattell and John L. Horn (Focused on the division between fluid and crystallized intelligence), which Carroll himself had championed before creating his own. The assimilation of the two perspectives into one can be attributed to Kevin McGrew (2012).
The three layers of cognitive form
Carroll’s theoretical proposition can be included in the category of hierarchical models of intelligence, as it describes three strata ranging from the most specific samples of cognitive ability to its general appearance, which is specified in the construct “g-factor”. These skills would have a stable character, according to the author.
Carroll said that these abilities can probably be attributed to variables of a physiological type. In this regard, it should be mentioned that authors such as Philip Vernon (who developed his own theory on the structure of intelligence) and Hans Eysenck have linked cognitive skills to the efficiency and quality of intelligence. neuronal transmission.
1. First layer: primary mental skills
According to Carroll, the lower layer of the intelligence structure is formed by primary mental abilities, which include a large number of cognitive abilities: quantitative reasoning, spelling, visualization, Ability for foreign languages, discrimination of speech sounds, mastery of ideas, reaction time, etc.
The results of factor analyzes carried out by Carroll and other later authors reveal that each of these skills, which have a high degree of specificity, they weigh on one of the complex factors of the second stratum depending on the characteristics of the stimulating material and the overall capacity on which they depend.
2. Second level: complex factors
At this level we find a wide range of cognitive skills. Carroll initially proposed the presence of 10 factors in the second stratum, although later research reduced the number to 8:
- Fluid intelligence: the ability to reason and solve problems using new information.
- Crystallized intelligence: refers to the depth and amount of verbal knowledge acquired and the processing of this data.
- General memory and learning: the ability to learn in general with specific skills such as information retention or short-term retrieval.
- Extensive Research Ability: Includes the ability to fluently manage ideas and associations, both verbally and in pictures.
- Visual processing: the ability to perceive, analyze, remember and function with visual stimulation.
- Auditory processing: the ability to discriminate and process sounds, including those associated with speech and those associated with music.
- Broad cognitive speed: refers to the speed at which stimuli are manipulated during tests (e.g. numbers) and completed.
- Processing speed: Ability to perform automatic cognitive processes, especially maintaining selective attention.
Each of these factors includes several lower order factors corresponding to the first stratum. So, for example, crystallized intelligence includes reading comprehension, spelling, and foreign language proficiency, while extended research ability is derived from tests of creativity and mastery of different types of material.
3. Third layer: general intelligence or g-factor
The third layer of the structure defined by Carroll it is made up of the general intelligence factor, A construct known as the “g-factor” and which is used by a large number of psychologists. This higher-order aptitude would influence all the aptitudes included in the second stratum, and therefore also those of the third indirectly.
- Carroll, JB (1993). Human cognitive skills: a survey of studies of analytical factors. New York: Cambridge University Press.
- Hogan, TP (2004). Psychological tests: a practical introduction. Buenos Aires: modern manual.
- Horn, J. and Cattell, R. (1966). Refinement and proof of the theory of fluid and crystallized general intelligences. Journal of Educational Psychology, 57: 253-70.
- McGrew, K. (2012). Cognitive skills. In DP Flanagan and PL Harrison (Eds.), “Contemporary Intellectual Evaluation: Theories, Evidence, and Questions”. New York: Guilford Press.