Charles Spearman
Charles Edward Spearman ( born September 10, 1863 in London, † September 17, 1945 in London) was a British psychologist who was known among other things for his 1904 published two factor theory of intelligence.
Biography
Charles Spearman in 1897 took his degree in psychology with Wilhelm Wundt in Leipzig without any formal qualifications. Previously, he had been for 15 years an officer in the British Army in various colonial wars. His studies were interrupted by a convocation in the Boer War. In 1904 he received his doctorate in Wundt with a study on the perception of space and then went to further studies of the physiology, psychology and philosophy continue to Würzburg to Oswald Külpe, then to Göttingen and Berlin.
Through his exchange with the psychologist William McDougall, he was able to contact the University College London and in 1907 was McDougall's successor as lecturer with a small psychological laboratory. In 1911 he became a professor of the philosophy of mind and logic. With the creation of a separate Department of Psychology 1928, he received until his retirement in 1931 the title of " Professor of Psychology ". He was succeeded by Cyril Burt. After his retirement he wrote a comprehensive history of psychology and taught still in Chicago and Cairo.
His statistical work has been heavily criticized by his colleague, the biostatistician Karl Pearson at the same university and it developed a long feud between the two.
In 1924 he was elected a Fellow of the Royal Society.
Among his pupils were Raymond Bernard Cattell and David Wechsler.
Mathematical Psychology
Charles Spearman led - inspired by Francis Galton - many statistical methods in psychology and was a key developer of the " Classical Test Theory." He set out overall considerations for the correlation measurement to the measurement errors and the reliability (reliability ) psychological measurement. In his famous study of the intelligence of 24 village school children, he pointed to the limitation of correlation by the reliability of the individual tests. For a known reliability of individual tests can be expected out of this influence.
- Spearman's rho ( Spearman's rank correlation coefficient ): A distribution-free (non- parametric ) correlation for data on rank scale level. This also allows the correlation of data from rankings are calculated together. It is based on the Pearson product-moment correlation coefficient, are used in the rankings. It can not be used for bound ranks sensible, but only halfway same or randomly distributed rank intervals.
- Spearman - Brown formula ( Spearman - Brown prophecy -formula ): In the examination of the reliability (reliability ) of psychological measurements using the Spearman - Brown formula today: In order to check the internal consistency of a test using the split-half method ( test halves must be parallel to ) the individual test tasks (items ) are alternately assigned to two groups, which are then correlated with each other. However, this correlation underestimates the internal consistency because the real test is indeed twice as long. On this basis, but the reliability of the overall test can be estimated with the Spearman - Brown formula. General can be estimated with this formula, the effects of shortening or lengthening the test on its reliability. Similarly, the formula is used in the investigation of the judgments interrater agreement.
In his study of 1904, he first put coherently the concept of factor analysis is, even if Karl Pearson had already developed basic ideas. His method is called that of the tetradic differences. These ideas were further driven in 1909 by Cyril Burt. Louis Leon Thurstone in 1931 practiced basic criticism of Spearman's intelligence theory and method, and developed a Multiple Factor Analysis ( Zentroidmethode ), with which he came to a different conclusion.
Intelligence research
Spearman compared the performance of people in various performance tests and found that those who were good in a test tends performed well in other tests. Therefore, he adopted a uniform ability of intelligence that underlies all intellectual performance based. She squeezed in a general factor (called " general factor " or "g - factor " ) of which should be a measure of general and innate " spiritual energy ". In the processing of the various tests in addition come each specific independent skills at work: the s- factors (eg, verbal skills, spatial imagination). This two-factor theory of intelligence, he underscored by the results of factor analyzes. However, in follow-up studies could not confirm the alleged independence of the s- factors. Therefore Spearman spoke later of group factors that several benefits are together as the basis - without abandoning the basic statements of his intelligence theory.
Louis Leon Thurstone criticized this theory as an artifact of the methodology and isolated with its test and its factor analysis, seven relatively independent factors of mental skills (primary mental abilities ).
Raymond Bernard Cattell tried the Spearman model in a hierarchical model of intelligence to preserve by identified two second order factors. Fluid intelligence here refers to the current ability to quickly and efficiently deal with new challenges and crystallized intelligence more strategic knowledge and experience component intelligent action.
To date, however, the discussion of these basic concepts of intelligence to (Intelligence Quotient ) holds.