Carroll’s Three-Layered Theory of Intelligence

This theory proposes that human intelligence can be divided into three levels of complexity.

John B. Carroll's three strata theory of intelligence proposes that the factor structure of human cognitive skills is composed of a general intellectual capacity (the g factor), a set of 8 broad skills, such as mental processing speed or memory, and a third stratum that would include more specific intellectual skills dependent on one of the previous ones.

In this article we will analyze Carroll's model, which today is usually studied and applied in conjunction with the theory of fluid and crystallized intelligences proposed by Cattell and Horn. We will focus in particular on the analysis of each of the layers of intelligence described by this author.

John Carroll's theory of intelligence

The American psychologist John Bissell Carroll (1916-2003) is known mainly for his contributions in the field of psychometrics on 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.

In particular, his three-strata theory, a model based on the results of hundreds of based on the results of hundreds of factor analyses on samples of numerical data that can be on samples of numerical data that can serve as predictor variables of intelligence, such as IQ tests or the scores obtained in academic assessment tests.

Carroll presented the results of his studies together with his theory of intelligence in the work entitled "Human Cognitive Abilities: An Investigation of Factor-Analytic Studies", which was published in 1993. In this book he emphasized the distinction between aptitudes related to individual differences and those derived from the quality of education.

Today, Carroll's theory of the three strata is considered complementary to Raymond Raymond's model. is considered to be complementary to the model of Raymond B. Cattell and John L. Horn (centered on the division between fluid and crystallized intelligence), which Carroll himself had defended before creating his own. The assimilation of both perspectives into one can be attributed to Kevin McGrew (2012).

The three layers of cognitive aptitude.

Carroll's theoretical proposal can be included in the category of hierarchical models of intelligence, since it describes three strata that go from the most specific samples of cognitive aptitude to its general aspect, which is concretized in the construct "g-factor". These aptitudes would have a stable character, according to the author.

Carroll stated that these aptitudes can probably be attributed to physiological variables.. In this sense, it is worth mentioning that authors such as Philip Vernon (who developed his own theory on the structure of intelligence) and Hans Eysenck have related cognitive aptitudes to the efficiency and quality of neuronal transmission.

1. First stratum: primary mental aptitudes.

According to Carroll the lower stratum of the structure of intelligence is formed by the primary mental aptitudes, which include a large number of cognitive abilities: quantitative reasoning, spelling, visualization, aptitude for foreign languages, discrimination of speech sounds.The results of the factorial analyses used in this study are based on the results of the factorial analysis of the results of the study.

The results of the factor analyses carried out by Carroll and later authors reveal that each of these skills, which have a high degree of specificity, are weighted in one of the complex factors, weight in one of the complex factors of the second stratum, depending on the depending on the characteristics of the material to be stimulated and the global ability on which they depend.

2. Second layer: complex factors

At this level we find a set of broad cognitive skills. Carroll originally proposed the presence of 10 factors in the second layer, although later research reduced the number to 8:

• Fluid intelligence: aptitude for reasoning and problem solving using novel information.
• Crystallized intelligence: referred to the depth and quantity of verbal knowledge acquired and the handling of this type of data. and the handling of this type of data.
• General memory and learning: ability to learn in general along with specific skills such as retaining information or retrieving it in the short term.
• Broad retrieval capacity: includes the ability to fluently handle ideas and associations, both verbally and in images.
• Visual processing: ability to perceive, analyze, recall and operate with visual stimulation.
• Auditory processing: ability to discriminate and process sounds, including those associated with speech and music.
• Broad cognitive speed: refers to the speed to handle stimuli during tests (e.g., numbers) and to complete them.
• Processing speedThe ability to execute automatic cognitive processes, particularly while maintaining selective attention.

Each of these factors encompasses several lower-order factors corresponding to the first stratum. Thus, for example, crystallized intelligence includes reading comprehension, spelling and foreign language ability, while broad retrieval ability is derived from tests of creativity and fluency with different types of material.

3. Third layer: general intelligence or g-factor

The third stratum of the structure defined by Carroll is constituted by the general intelligence factora 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 stratum indirectly.