|Born||Charles Edward Spearman
10 September 1863
London, United Kingdom
|Died||17 September 1945
London, United Kingdom
|Institutions||University College London|
|Alma mater||University of Leipzig, Germany|
|Notable students||Raymond Cattell, John C. Raven, David Wechsler|
|Known for||g factor, Spearman's rank correlation coefficient, factor analysis|
|Influences||Francis Galton, Wilhelm Wundt|
|Influenced||Hans Eysenck, Philip E. Vernon, Cyril Burt, Arthur Jensen|
|Notable awards||Fellow of the Royal Society|
Charles Edward Spearman, FRS (10 September 1863 – 17 September 1945) was an English psychologist known for work in statistics, as a pioneer of factor analysis, and for Spearman's rank correlation coefficient. He also did seminal work on models for human intelligence, including his theory that disparate cognitive test scores reflect a single General intelligence factor and coining the term g factor.
Spearman had an unusual background for a psychologist. In his childhood he was ambitious to follow an academic career. He first joined the army as a regular officer of engineers in the British Army. After 15 years he resigned to study for a PhD in experimental psychology. In Britain, psychology was generally seen as a branch of philosophy and Spearman chose to study in Leipzig under Wilhelm Wundt, because Spearman had no conventional qualifications and Leipzig had liberal entrance requirements. There he met Krueger and Wirth, both of whom he really admired. He started in 1897, and after some interruption (he was recalled to the army during the South African War) he obtained his degree in 1906. He had already published his seminal paper on the factor analysis of intelligence (1904). Spearman met and impressed the psychologist William McDougall who arranged for Spearman to replace him when he left his position at University College London. Spearman stayed at University College until he retired in 1931. Initially he was Reader and head of the small psychological laboratory. In 1911 he was promoted to the Grote professorship of the Philosophy of Mind and Logic. His title changed to Professor of Psychology in 1928 when a separate Department of Psychology was created.
When Spearman was elected to the Royal Society in 1924  the citation read "Dr. Spearman has made many researches in experimental psychology. His many published papers cover a wide field, but he is especially distinguished by his pioneer work in the application of mathematical methods to the analysis of the human mind, and his original studies of correlation in this sphere. He has inspired and directed research work by many pupils." Chief amongst these achievements was the discovery of the general factor in human intelligence,  and his subsequent development of a theory of "g"  and synthesis of empirical work on ability.
In statistics, Spearman developed rank correlation (1904), a non-parametric version of the conventional Pearson correlation, as well as both the widely used correction for attenuation (1907), and the earliest version of a 'factor analysis' (Lovie & Lovie, 1996, p. 81) . His statistical work was not appreciated by his University College colleague Karl Pearson and there was a long feud between them.
Although Spearman achieved most recognition in his day for his statistical work, he regarded this work as subordinate to his quest for the fundamental laws of psychology, and he is now similarly renowned for both.
Charles Spearman always insisted that his work be should be applied in psychiatry and urged so in his Maudsley lecture to the Royal Medico-Psychological Association. While some work has been made on these lines by pupils and associates of his, the development of factor analysis as a tool of psychiatry followed a different path than he had intended. Regardless his indirect contributions towards psychiatry were considerable.
Spearman's life both began and ended in the city of London. He had three daughters along with one son, who died early on in 1941 in Crete.
Theory of intelligence 
Here, Spearman gives a compact summary of his findings and theory of g:
- When asked what G is, one has to distinguish between the meanings of terms and the facts about things. G means a particular quantity derived from statistical operations. Under certain conditions the score of a person at a mental test can be divided into two factors, one of which is always the same in all tests, whereas the other varies from one test to another; the former is called the general factor or G, while the other is called the speciﬁc factor. This then is what the G term means, a score-factor and nothing more. But this meaning is sufﬁcient to render the term well deﬁned so that the underlying thing is susceptible to scientiﬁc investigation; we can proceed to ﬁnd out facts about this score-factor, or G. We can ascertain the kind of mental operations in which it plays a dominant part as compared with the other or speciﬁc factor. And so the discovery has been made that G is dominant in such operations as reasoning, or learning Latin; whereas it plays a very small part indeed in such operation (sic) as distinguishing one tone from another. . . G tends to dominate according as the performance involves the perceiving of relations, or as it requires that relations seen in one situation should be transferred to another. . . . On weighing the evidence, many of us used to say that this G appears to measure some form of mental energy. But in the ﬁrst place, such a suggestion is apt to invite needless controversy. This can be avoided by saying more cautiously that G behaves as if it measured an energy. In the second place, however, there seems to be good reason for changing the concept of energy to that of "power" (which, of course, is energy or work divided by time). In this way, one can talk about mind power in much the same manner as about horse power. . . . . . .G is in the normal course of events determined innately; a person can no more be trained to have it in higher degree than he can be trained to be taller. (pp. 156 –157).
There was also another co-factor as proposed by Spearman that was special intelligence. The special intelligence was for individuals who accomplished high success results in the some tests. However, later Spearman introduced group factor that was particular to those correlations that were not a result of factor g or s. His ideas were in 1938 criticized on paper by Louis L. Thurstone a psychologist saying that his experiments show that the correlation of intelligence can be categorized in seven primary categories. These categories were numerical, reasoning, spatial, perceptual, memory, verbal fluency and verbal comprehension. However Raymond B. Cattell in 1963 agreed with the concept theorized by Spearman but put forth his findings about intelligence analyses. His analyses were that intelligence is further subdivided in two divisions known as fluid and crystallized intelligence.
As time progressed, Spearman increasingly argued that g was not, from a psychological point of view, a single ability but composed of two very different abilities which normally worked closely together. These he called "eductive" ability and "reproductive" ability. The former term comes from the Latin root "educere" - which means to "draw out" and thus refers to the ability to make meaning out of confusion. He claimed that to understand these different abilities "in their trenchent contrast, their ubiquitous cooperation, and their genetic interlinkage" would, for the study of "individual differences - and even cognition itself" - be "the very beginning of wisdom.".
Despite Spearman arguing that g was what emerged from a large battery of tests, i.e., that it was not measured perfectly by any single test, the fact that g-theory suggested that much of ability could be captured in a single factor, and his suggestion that "the eduction of relations and correlates" underlay this general factor led to the quest for tests of this general ability. Raven's Progressive Matrices might be regarded as one of these although Raven himself clearly stated that his tests should not be regarded as "intelligence" tests.
While arguing consistently that g accounted for much of individual differences in "ability" (as measured by tests which had "no place in schools"), Spearman also acknowledged that "Every normal man, woman, and child is … a genius at something … It remains to discover at what …" He thought that detecting these areas of genius required procedures very different from "any of the testing procedures at present in current usage", though he felt these to be capable of "vast improvement".
While, like Arthur Jensen after him, Spearman felt that though g could be detected in any broad set of cognitive measures, he felt that the tests from which his g had emerged "had no place in schools" because they "deflected" teachers', pupils', parents' and politicians' attention from the business of education which, as the Latin root of the word implies, should be concerned with "drawing out" whatever talents a student may have .
Spearman's model was influential, but was also critiqued by many authors, such as, for instance Godfrey Thomson. In particular the move from a psychological g to a biological g – that is a unitary biological mechanism or mechanisms has remained a matter of active research.
Factor analysis 
Factor analysis is a statistical test that is used to find relationships between multiple correlated measures and Spearman played a clear part in its development. Spearman coined the term factor analysis and used it extensively in analyzing multiple measures of cognitive performance. It was factor analytic data which lead Spearman to postulate his original general and specific factor models of ability. Spearman applied mathematical procedures to psychological phenomena, and molded the outcome of his analysis into a theory - which has greatly influenced modern psychology.  Factor analysis and its modern relations confirmatory factor analysis and structural equation modelling underlie much of modern behaviour research.
- Thomson, Godfrey (1947). "Charles Spearman. 1863-1945". Obituary Notices of Fellows of the Royal Society 5 (15): 373. doi:10.1098/rsbm.1947.0006.
- Lovie, P.; Lovie, A. D. (1996). "Charles Edward Spearman, F.R.S. (1863-1945)". Notes and Records of the Royal Society 50: 75. doi:10.1098/rsnr.1996.0007.
- Spearman, C. (1904). ""General Intelligence," Objectively Determined and Measured". The American Journal of Psychology 15 (2): 201–292. doi:10.2307/1412107.
- Lovie, Pat (2005). "Spearman, Charles Edward". Encyclopedia of Statistics in Behavioral Science. doi:10.1002/0470013192.bsa634. ISBN 0470860804.
- Thomson, Godfrey (1947). "Charles Spearman". The Royal Society. pp. 373–385.
- Ogden, R. M.; Spearman, C. (1925). "The Nature of 'Intelligence' and the Principles of Cognition, 1923". The American Journal of Psychology 36 (1): 140–145. doi:10.2307/1413513.
- Spearman, Charles B. (2005). The Abilities of Man: Their Nature and Measurement. The Blackburn Press. ISBN 1-932846-10-7.
- "The Lancet" A Chair of Anatomy. October 1945. pg. 440
- Deary, I. J.; Lawn, M.; Bartholomew, D. J. (2008). ""A conversation between Charles Spearman, Godfrey Thomson, and Edward L. Thorndike: The International Examinations Inquiry Meetings 1931-1938": Correction to Deary, Lawn, and Bartholomew (2008)". History of Psychology 11 (3): 163. doi:10.1037/1093-4510.11.3.163.
- Edward Roy; Bernstein, Douglas A.; Penner, Louis A.; Clarke-Stewart, Alison (2007). Psychology. Boston: Houghton Mifflin. ISBN 0-618-87407-0.
- Spearman, C. (1925). "Some Issues in the Theory of "g" (including the Law of Diminishing Returns)". Nature 116 (2916): 436. doi:10.1038/116436a0.
- Williams, R. H., Zimmerman, D. W., Zumbo, B. D. & Ross, D. (2003). Charles Spearman: British Behavioral Scientist. Human Nature Review. 3: 114-118
- Spearman, C. (1950). Human Ability, Macmillan, London.
- "The Chair of Anatomy". The Lancet 246 (6371): 440–440. October 1945. doi:10.1016/S0140-6736(45)91700-4.
Further reading 
- Spearman, C. (1987). "The proof and measurement of association between two things. By C. Spearman, 1904". The American journal of psychology 100 (3–4): 441–471. PMID 3322052.
- Spearman, C. (2010). "The proof and measurement of association between two things". International Journal of Epidemiology 39 (5): 1137–1150. doi:10.1093/ije/dyq191. PMID 21051364.
- Spearman, C. (1907). "Demonstration of Formulæ for True Measurement of Correlation". The American Journal of Psychology 18 (2): 161–169. doi:10.2307/1412408.
- Gregory, Robert J. (2011). Psychological Testing: History, Principles, and Applications (Sixth ed.). Boston: Allyn & Bacon. ISBN 978-0-205-78214-7. Lay summary (7 November 2010).
- Mackintosh, N. J. (1998). IQ and Human Intelligence. Oxford: Oxford University Press. ISBN 978-0-19-852367-3. Lay summary (9 August 2010).
- Charles Spearman at Human Intelligence
There is a photograph of Spearman at