Charles Edward Spearman (born September 10, 1863 in London ; † September 17, 1945 ibid) was a British psychologist who became known, among other things, for his two-factor theory of intelligence , published in 1904 .
Charles Spearman began studying psychology with Wilhelm Wundt in Leipzig in 1897 without formal qualifications. Previously, he had been an officer in the British Army in various colonial wars for 15 years . His studies were interrupted by a draft into the Boer War. In 1904 he did his doctorate with Wundt with an investigation into spatial perception and then went on to further studies in physiology, psychology and philosophy to Würzburg to Oswald Külpe , then to Göttingen and Berlin.
Through his exchange with the psychologist William McDougall , he got in touch with University College London and in 1907 he was McDougall's successor as a lecturer with a small psychological laboratory. In 1911 he became professor there for the philosophy of mind and logic. With the creation of his own department for psychology in 1928, he received the title of Professor of Psychology until he left in 1931 . He was succeeded by Cyril Burt . After his departure, he wrote an extensive history of psychology and still taught in Chicago and Cairo .
His statistical work was heavily criticized by his colleague, biometrician Karl Pearson at the same university, and a long feud developed between the two.
Spearman was heavily influenced by Francis Galton. Galton was known for his pioneering work in psychology and developmental correlations, which Spearman mainly used as a tool.
Charles Spearman - encouraged by Francis Galton - introduced many statistical methods into psychology and was a major developer of the " classical test theory ". He made fundamental considerations on correlation measurement, measurement errors and the reliability ( reliability ) of psychological measurement. In his famous study of the intelligence of 24 village school children, he showed that the correlation was limited by the reliability of the individual tests. If the reliability of the individual tests is known, this influence can be calculated.
- Spearmans Rho (Spearman's Rank Correlation Coefficient ): A non-parametric correlation measure for data at the rank scale level. This also enables the relationship between data to be calculated from rankings. The basis is Pearson's product-moment correlation coefficient, in which the rankings are used. It cannot be used meaningfully in the case of bound ranks, but only in the case of halfway equal or randomly distributed rank differences.
- Spearman-Brown- Prophecy -Formula : In the investigation of the reliability ( reliability ) of psychological measurements, the Spearman-Brown formula is still used today: In order to check the internal consistency of a test, after the split Half method (test halves must be parallel) the individual test items (items) are alternately assigned to two groups, which are then correlated with each other. However, this correlation underestimates the internal consistency, since the real test is twice as long. On this basis, however, the Spearman-Brown formula can be used to estimate the reliability of the overall test. More generally, this formula can be used to estimate what effect shortening or lengthening the test will have on its reliability. The formula is also used in the investigation of judgment agreement.
In his study of 1904 he presented the concept of factor analysis for the first time in a coherent manner, even though Karl Pearson had already developed basic ideas for it. His method is called that of tetradic differences. Cyril Burt took these ideas further in 1909 . Louis Leon Thurstone made fundamental criticism of Spearman's intelligence theory and method in 1931 and developed a multiple factor analysis (centroid method) with which he came to different conclusions.
Spearman compared people's performance on different proficiency tests and found that those who did well on one test tended to do well on other tests as well. Therefore he assumed a 'unified ability' of intelligence that underlies all intellectual performance. It was expressed in a general factor (called the " general factor " or "g-factor"), which should be a measure of the general and innate "mental energy". When processing the various tests, specific, independent skills also come into play: the s-factors (e.g. verbal skills, spatial imagination). He supported this two-factor theory of intelligence with the results of his factor analyzes. However, the claimed independence of the s-factors could not be confirmed in subsequent investigations. That is why Spearman later also spoke of group factors that underlie several achievements in common - without giving up the basic statements of his intelligence theory.
Louis Leon Thurstone criticized this theory as an artifact of the underlying method and isolated with his tests and factor analysis seven relatively independent factors of mental abilities (primary mental abilities).
Raymond Bernard Cattell tried to preserve the Spearman model in a hierarchical model of intelligence by determining two factors of the second order. Fluid intelligence describes the current ability to deal quickly and efficiently with new challenges and crystalline intelligence more the strategic knowledge and experience component of intelligent action.
To this day, however, the discussion about these basic concepts of intelligence ( intelligence quotient ) continues.
- 1904a: The proof and measurement of association between two things , American Journal of Psychology 15, 72-101
- 1904b: 'General intelligence' objectively determined and measured , American Journal of Psychology 15, 201–293 
- 1907: Demonstration of formulas for true measurement of correlation , American Journal of Psychology
- 1910: Correlation calculated from faulty data , British Journal of Psychology, 3, 271-295.
- 1914: The theory of two factors , Psychological Review, 21, 101-115
- 1923: The nature of intelligence and the principles of cognition , (1922?)
- 1927: The abilities of man, their nature and measurement
- 1930: G and after - a school to end schools
- 1930: Creative mind
- 1930: Autobiography in: Murchinson, C. (Ed.): A history of psychology in autobiography . Vol. 1 Worcester (Mass.), 1930, 299-333
- 1937: Psychology down the ages , (2 vol.)
- 1951: Human abilities , (co-author LW Jones)
- Williams, RH, Zimmerman, DW, Zumbo, BD & Ross, D. (2003). Charles Spearman: British Behavioral Scientist. Human Nature Review. 3: 114–118  (PDF; 218 kB) -
|ALTERNATIVE NAMES||Spearman, Charles Edward (full name)|
|BRIEF DESCRIPTION||British psychologist|
|DATE OF BIRTH||September 10, 1863|
|PLACE OF BIRTH||London|
|DATE OF DEATH||September 17, 1945|
|Place of death||London|