Intelligence Types and Theories

Charles Spearman, in 1904 made the first factor analysis of correlations between the tests. Spearman observed that children's performance ratings across unrelated school subjects were positively correlated. He suggested that these correlations were the result of an underlying general mental ability that influenced all kinds of mental tests. Spearman proposed that an individual's mental performance is the result of a single general ability factor, which he called g, and many narrow special ability factors.

The g factor (or general intelligence or general intelligence factor) is a psychometric construct that governs all cognitive tasks and abilities. G factor is a variable that summarizes positive correlations among different cognitive tasks and mental tests. One's performance on one kind of cognitive task tends to be comparable to the same person's performance on other kinds of cognitive tasks. IQ, g factor, general intelligence, general cognitive ability, and simply intelligence are terms used interchangeably to refer to what cognitive tests try to measure.

Charles Spearman developed the two-factor theory of intelligence using factor analysis, which includes the g factor of general intelligence, and the s factor of specific cognitive abilities (verbal, spatial, numerical, and mechanical). Spearman developed a procedure named factor analysis, in which related variables are tested for correlation to each other, and then the correlation of the related items is evaluated to find groups of the variables. He tested how well people performed on different mental tasks, such as distinguishing pitch, perceiving weight and colors, directions, and mathematics. When analyzing the data he collected, he noticed that an individual's performance on one kind of cognitive task tends to be comparable to the same person's performance on other kinds of cognitive tasks. Spearman concluded that there is one g factor that influences all cognitive abilities, but also the s factor of specific intellectual abilities (verbal, spatial, numerical, and mechanical).

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 cognitive ability to solve novel problems (like number series and shape 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.

Robert Sternberg theorized the Triarchic Theory of Intelligence and challenged the concept of g-factor, and took a more cognitive approach, and it’s categorized as a cognitive-contextual theory. The three components are called triarchic components. Sternberg associated the processes of the mind with a series of cognitive components, which he called: meta-components, performance components, and knowledgeacquisition components. Sternberg proposed that the basic information processing components underlying the three parts of his triarchic theory are the same; different contexts and different tasks require different kinds of intelligence.

Sternberg separated his theory into the following three sub-theories: the contextual sub-theory, which says that intelligence is based on how the individual interacts with their environment, the experiential sub-theory, which says that there is a continuous sequence of experience from novel to automation to which human intelligence can be applied; and the componential sub-theory, which outlines the various mechanisms that result in intelligence. Sternberg suggested that intelligence is comprised of three parts: practical intelligence (contextual sub-theory), creative intelligence (experiential sub-theory), and analytical intelligence (componential sub-theory).

Practical intelligence is related to finding solutions that work in your everyday life by applying prior knowledge, experience, and common sense. Analytical intelligence is related to academic problem solving, and it’s demonstrated by an ability to analyze, evaluate, judge, compare, and contrast. Creative intelligence is related to imagining a solution to a problem or situation, finding a novel solution to an unexpected problem, or creating a beautiful work of art or well-developed literature.

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 9 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.

Louis Leon Thurstone challenged the concept of a g-factor and developed a model of intelligence centered on "Primary Mental Abilities." After analyzing data from tests of mental abilities, he identified several primary mental abilities that constitute intelligence, as opposed to one general factor of intelligence. The seven primary mental abilities in Thurstone's model are verbal comprehension, verbal fluency, number facility, spatial visualization, perceptual speed, associative memory, and inductive reasoning.

Verbal comprehension is the cognitive ability to understand the meaning of words, concepts, and ideas. Verbal fluency is the ability to use words quickly and fluency in performing rhyming, solving anagrams, and doing crossword puzzles. Number facility is the ability to use numbers to quickly computer answers to problems. Spatial visualization is the cognitive capacity to visualize and manipulate patterns, objects, and forms in space. Perceptual speed is the mental ability to grasp perceptual details quickly and accurately and to determine similarities and differences between stimuli. Associative memory is the ability to recall information such as lists of words, arithmetic and mathematical formulas, and definitions of concepts. Inductive reasoning is the cognitive ability to produce general rules and principles from the presented information.

Howard Gardner introduced nine types of intelligence: verbal-linguistic, logicalmathematical, visual-spatial, bodily-kinesthetic, musical-rhythmic, interpersonal, intrapersonal, naturalistic, and existential.

Verbal-linguistic intelligence is the mental ability to analyze information, solve problems using language-based reasoning, use words and combinations effectively in communication, think in words, and use language to express and manipulate complex meanings. It is the individual’s fundamental ability to use written and verbal language to achieve their goals.

Logical-mathematical intelligence is the mental ability to calculate, quantify, manipulate numerical symbols, carry out numerical and mathematical operations, solve numerical problems regularly, make decisions based on numerical information, consider propositions, use abstract and symbolic thought, sequential reasoning, inductive and deductive thinking patterns, critical thinking, analyze problems, identify solutions, use abstractions, recognize patterns, detect connections, and conduct scientific research.

Visual-spatial intelligence is the cognitive ability to think in three dimensions, solve spatial problems of navigation, visualize objects from different angles and space, recognize faces or scenes, notice fine details, manipulate mental images, and do graphic and artistic work. It is the individual’s ability that helps them identify and manipulate visual and spatial patterns and orient in their environment.

Bodily-kinesthetic intelligence is the cognitive ability to manipulate objects and use a variety of physical skills, involves a sense of timing and a clear sense of the goal of physical activity, as demonstrated by athletes, dancers, surgeons, and craftspeople.

Musical-rhythmic intelligence is the mental capacity to discern pitch, rhythm, timbre, and tone and to recognize, create, reproduce music, as demonstrated by composers, conductors, musicians, vocalists, and sensitive listeners.

Interpersonal intelligence is the cognitive ability to understand and interact effectively with other people and be sensitive to other people’s moods, feelings, temperaments, motivations, cooperate as part of a group, and have the capacity to note distinctions among others and entertain multiple perspectives.

Intrapersonal intelligence is the mental capacity to have introspection and selfreflection, understand oneself, one’s thoughts and feelings, strengths and weaknesses, and use such knowledge in planning one’s life.

Naturalistic intelligence is the cognitive ability to discriminate among living things and other features and objects of the natural world, recognize flora and fauna, make a variety of consequential distinctions in the natural world, and use this ability productively.

Existential intelligence is the mental capacity to answer philosophical questions about human existence, such as the meaning of human life, why we die, and how did we get into this world.