CHARLES SPEARMAN: BIOGRAPHY, THEORIES - PSYCHOLOGY - 2025

Charles Spearman (1863-1945) was a London psychologist known for formulating the bifactorial theory, which consists of affirming that intelligence is composed of two elements: the general factor (G), which refers to hereditary traits; and the special factor (S), related to the specific abilities of each subject.

Spearman assured that intelligence is constituted by a strong hereditary component (G factor), however, the training that an individual receives during his life also exerts a notable influence on intelligence; here the S factor is introduced, which encompasses all the experiences and skills developed by man in the course of his existence.

Charles Spearman. Source: Eugène Pirou

In order to corroborate his theory, Spearman developed a statistical technique he called 'factor analysis', which worked as a complement to his approach. Factor analysis was one of the most important contributions made by the author, since it implied great advances in the disciplines of statistics and psychology.

Another compelling contribution of Spearman was the creation of the concept of 'ordinal correlation coefficient', which allows relating two variables through ranges instead of calculating the performance of each one separately.

This correlation coefficient was dubbed Spearman's Rho, after the researcher. According to the author Enrique Cabrera, in his text Spearman's rank correlation coefficient (2009), the Rho measures the degree of association that exists between two elements, however, it does not calculate the levels of concordance.

Therefore, it is recommended to use it only when extreme values ​​or abnormal distributions occur in the data.

Biography

- Birth and studies

Charles Edward Spearman was born in London, England, on September 10, 1863. He studied at several prestigious institutions in Europe, such as Leipzig and Würzburg (Germany) and Gottingen (Great Britain) universities, where he trained in the discipline of psychology.

Between 1907 and 1931, he taught at the University of London, where he also carried out his research and wrote his most important works, among which are The Abilities of Man (1927) and The Creative Mind (1930).

Other important works by Chales Spearman were Psychology in the Ages (1937), The Nature of Intelligence and the Principles of Cognition (1923), and The Proof and Measure of the Association Between Two Things (1904).

- Main works

The skills of man

In the first part of this text, Spearman presented the various doctrines of intelligence, which were grouped by the author into three main groups: "monarchical", "oligarchic" and "anarchic".

Then, the psychologist extensively explained his hypothesis about the existence of two factors that influence the mental energy of man, where he mentioned the G factor and the S factor.

In the second part of the book, Spearman compiled and described a series of fundamental facts based on the experiments carried out in his own laboratory and elsewhere, where he applied the criterion of tetrad differences - group of four chromatid structures - in the tables of correlations.

Creative mind

In this work, the author covered everything concerning the mental creation of man, approaching it from the different spheres of activity.

Likewise, he mentioned two important aspects that condition creation: the emotional impulse -related to the subjective part of the individual- and the mechanisms -the techniques that allow creation to be carried out.

One of the peculiarities of this text is that it has a remarkable visual support, since Spearman selected several works and paintings by notable artists. For this reason, The Creative Mind is not a book reviewed only by psychologists, but also by art students.

"The Creative Mind" was one of Spearman's most acclaimed books. Source: pixabay.com

- Death and other data of the author

Charles Spearman passed away on September 17, 1945 at the age of 82 in his native London, after having made a fruitful career in psychological discipline. During his academic and research development, the author belonged to the German Academy of Natural Sciences Leopoldina and was also a member of the Royal Society.

Theories

The two-factor theory

Spearman's bifactorial theory is based on the creation of a system governed by two factors: the special factor (S) and the general factor (G). This theory was published in 1923, after Spearman verified that the student performance of a group of students was related to the result obtained from sensory tests conducted by the same psychologist.

Thanks to this experiment, the author was able to verify that general intelligence could be calculated through the 'sensory discrimination capacity', which consists of the way in which individuals - in this case, students - perceive or capture information through the senses.

Regarding general intelligence, the London psychologist defined it as the ability to infer relationships and provide correlates. Likewise, he affirmed that this intelligence has the ability to intervene in many activities, however, it is not specifically dedicated to any of them, on the contrary to the S factor.

On the other hand, the special factor -also known as a specific factor- is one that corresponds to different human abilities, such as verbal, numerical, spatial, mechanical activities, among others.

The rank correlation coefficient

Spearman's coefficient, also known as Spearman's Rho, is a type of measure that uses ranges and works by linear association. The objective of the Rho is to calculate the ranges of two elements determined simultaneously, without having to deduce the ranges separately.

In order to interpret the statistical tests using Spearman's correlation, the object of the investigation must be taken into account, which is defined before starting the analysis. In addition, the relevance of the relationships to be calculated within the phenomenon under study must also be determined.

Therefore, the researcher should not base his foundations only on the mathematical figures obtained, but should be based on scientific experiences related to the investigated topic; this in order to avoid the interference of chance.

This is because the Spearman correlation is a purely mathematical measure, so it is free from any implication of cause and effect.

References

1. Bonastre, R. (2004) General intelligence (g), neural efficiency and nerve conduction velocity index. Retrieved on October 14, 2019 from TDX: tdx.cat
2. Cabrera, E. (2009) The correlation coefficient of Spearman's ranks. Retrieved on October 14, 2019 from Scielo: scielo.sld.cu
3. Pérez, A. (2013) Contemporary theories of intelligence. Retrieved on October 14, 2019 from Redalyc: Redalyc.org
4. Santiago, C. (2019) Spearman's bifactorial theory of intelligence. Retrieved on October 14, 2019 from The mind is wonderful: lamenteesmaravillosa.com
5. Spearman, C. (1907) Demostration of formulae for true measurement of corelation. Retrieved on October 15, 2019 from Jstor: jstor.org
6. Spearman, C. (1961) The proof and measurement of association between two things. Retrieved on October 14, 2019 from Psycnet: psycnet.apa.org
7. Williams, R. (2003) Charles Spearman: British behavioral scientist. Retrieved on October 14, 2019 from Human Nature Review: citeseerx.ist.psu.edu