Spearman’s two-factor theory of intelligence

Spearman’s approach represented a revolution, making us begin to question intelligence as a single and indivisible factor.

When talking about intelligence and its scientific study, we cannot omit, among others, the name of Charles Spearman. His studies provided a wealth of information and ideas for future thinkers. Why was Spearman’s two-factor theory so important to the study of intelligence and psychometric testing?

Intelligence has been studied and conceptualized scientifically by different thinkers. Among them Charles Spearman, who coined the term general intelligence in 1904 based on Galton’s studies.

Charles Spearman (1863 – 1945) was a psychologist born in London, a disciple of the father of experimental psychology, Wilhelm Wundt (1832 – 1920) and influenced by the work of Francis Galton (1822 – 1911). He was the founder of the London School of Psychology at University College London (UCL)where, together with many of his students, he put experimental psychology into practice during the first decades of the 20th century.

Spearman’s two-factor theory

Spearman stated in 1923, in his book two-factor theory of intelligence, that the academic performance of some school-age children was correlated with the result they obtained in sensory tests that he himself chose and applied to them. Thus, he concluded that General intelligence could be measured with the capacity for sensory discrimination, as Galton previously proposed.

Spearman’s two-factor theory proposes a system where intelligence is broken down into factors, the general factor (g) and the specific factor(s).

Within the scientific study of intelligence today, it is difficult to address the topic without talking about Spearman’s two-factor theory. This has remained the paradigm that He laid the foundations for a new stage of the study of intelligence.

General intelligence or G factor

Spearman defined general intelligence as “the ability to infer relationships and from them adduce correlates“. Likewise, he spoke of a “neural phenomenon g”, which is considered in his thesis as a potential energy available throughout the brain. Spearman postulates that this energy differs quantitatively between individuals and would be genetically determined.

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That is, it tells us about a part of the intelligence involved in many activities, however, does not specialize in any of them. Unlike specific actors or “factors”, that yes they do.

Specific factors or S factors

Also known as factors, are those that would correspond to different abilities such as mechanical, verbal, numerical, spatial activities, among others. So, Spearman’s two-factor theory tells us that if a school-age minor has good scores in one of the subjects, he will be more likely to also obtain good scores in the rest of them, since general intelligence or “general intelligence” intervenes in these evaluations. g.”

However, this does not guarantee that the minor will excel in any specific skill, discipline or area in the future, since for that it is necessary that the factors s.

Contributions to the study of intelligence

From Spearman’s two-factor theory and the different criticisms it received, other ideas emerged to try to scientifically understand the phenomenon of intelligence. Some of these criticisms were related to cultural bias, economic position, the geographical location of the subject’s home or their academic level.

Since Spearman’s two-factor theory does not take these factors into account and genetics cannot explain everything, new proposals and models emerged. Some of them are summarized in the following section.

Other definitions

There are many thinkers who followed Spearman’s line to develop theories based on the criticisms that arose. Here are some other definitions that have seemed relevant over time:

Hebb DO (1949 in The organization of the behavior), who states that ““Intelligence is the potential of an animal organism to learn and adapt to its environment.”Stemberg (1985 in Beyod IQ: A triarchic theory of human intelligence), who defines intelligence in the following way: “Intelligence explains the differences we observe between people in solving problemsGottfredson LS (1997 in Why g matters: The complexity of everyday life), who states that intelligence “It is a very general mental faculty which, among other things, involves the ability to react, plan, solve problems, think abstractly, understand complex ideas, learn quickly and learn from experience.”Howard Gardner (1999 in The prefrontal cortex: Executive and cognitive functions) who recognizes intelligence as “a biopsychological information processing potential to solve problems or create valuable products for a given culture or community.”

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These are some of the most important contributions about intelligence, and as we can see, are related to conflict resolution and environmental adaptation. Which indicates that they no longer only take into account the genetic conditions of the subjects.

Applications in psychology

In psychology, there are psychometric tests for almost all the dimensions that have aroused interest. Spearman’s two-factor theory, although not valued as much by some, is of great relevance. From these studies, others emerged that gave shape to different psychometric intelligence tests that we use today.

Psychometric tests based on Spearman’s two-factor theory are still administered today. For example, him Raven’s Progressive Matrices Test, Domino Test D-48 and the Cattell g factor test.

However, intelligence models in psychology are becoming increasingly complex as knowledge about the human mind increases. Therefore, Spearman should be taken as a basis for the current and not as a model in use. His contribution will always be inscribed in the chronology of this science of human behavior.