Charles Spearman

Born: September 10, 1863
Died: September 17, 1945

     Charles Edward Spearman was born in London and lived a full 82 years until his death in 1945. During those years Charles Spearman became one of the most influential figures that the field of psychology had seen. Despite his genuine interest however, he began not in psychology, but in philosophy. However, Spearman soon learned that he was not impressed by what philosophy had to offer him or by his own works in the faculty, it was for that reason that he had decided to join the army.

Spearman and the Army

     Spearman was not the type of person that enjoyed the military, yet he spent almost a quarter of his life in the British Army. This had been much longer than he had intended, however his reasoning was that he had wanted to take a job in which he could spend more time in his studies.
     During the Burmese War, Spearman received a medal and two clasps for his duties, but more importantly it was during this time that he discovered that, for him, the solutions to life's problems were in psychology. 
     This, however, was not the end of the military service for Spearman. On two other occasions he responded to the army's needs. First as Deputy Assistant Adjutant-General in Guernsey during the Boer War and again, during World War I, serving on the general staff of Tyne defences. It was after the first World War that his fame began to spread.

Educational and Professional Background

     Spearman was educated in Germany. He completed his Ph.D. under Wilhelm Wundt, but was also influenced during his studies by the works of Francis Galton and his case for the importance of intelligence testing. After studying at Leipzig, Wurzburg and Gottingen, Charles Spearman received his doctorate from Leipzig in 1904. With degree in hand, Spearman's professional career soared as he crossed the English Channel. In 1907, at University College; London, he took over the department of experimental psychology only to become Grote Professor of Mind and Logic in 1911. He continued to work at University College until 1931 when he then retired and became Emeritus Professor. Playing an active role in psychology, Spearman began to spend more and more time in North America teaching at Colombia University, the Catholic University of America and in Chicago where he played a crucial role in the designing of an experiment on "unitary differential traits." Spearman's work also took him to places such as Egypt where he pursued his teaching at the University of Cairo.
     With a strong statistical background, Spearman set out to estimate the intelligence of twenty-four children in the village school. In the course of his study, he realized that any empirically observed correlation between two variables will underestimate the "true" degree of relationship, to the extent that there is inaccuracy or unreliability in the measurement of those two variables. Further, if the amount of unreliability is precisely known, it is possible to "correct" the attenuated observed correlation according to the formula (where r stands for the correlation coefficient): r (true) = r (observed)  * sq. root of (reliability of variable 1 * reliability of variable 2). Using his correction formula, Spearman found "perfect" relationships and inferred that "General Intelligence" or "g" was in fact something real, and not merely an arbitrary mathematical abstraction. He then discovered yet another marvelous coincidence, the correlations were positive and hierarchal. These discoveries lead Spearman to the eventual development of a two-factor theory of intelligence.
     According to the two-factor theory of intelligence, the performance of any intellectual act requires some combination of "g", which is available to the same individual to the same degree for all intellectual acts, and of "specific factors" or "s" which are specific to that act and which varies in strength from one act to another. If one knows how a person performs on one task that is highly saturated with "g", one can safely predict a similar level of performance for a another highly "g" saturated task. Prediction of performance on tasks with high "s" factors are less accurate. Nevertheless, since "g" pervades all tasks, prediction will be significantly better than chance. Thus, the most important information to have about a person's intellectual ability is an estimate of their "g."
     Throughout his career Spearman had received many awards and honours for science. For instance, he was a Fellow of Royal Society, an Honorary L.L.D. of Wittenberg, a member of the Deutsche Akackmie der Naturforscher and a Foreign Associate of National Academy of Sciences of the U.S.A. Charles Spearman also became an Honorary Member of the British Psychological Society after a three year term as second President.

Contributions to the Testing Enterprise

     Charles Spearman contributed many theories and discoveries to the world of psychological testing. In one article entitled, "General Intelligence Objectivity Determined and Measured," Spearman set forth four discoveries: 

  • The first was that two measures which begin to have more variation cause the correlation to move towards zero (i.e. the value would have little meaning). 
  • The second was that one was able to use raw scores to compute true values, provided that the two measures are available. 
  • Thirdly, was that the equations used in the second law could be used to determine if the causes between two sets of measures have something in common with two other sets of measure. 
  • The fourth as stated by Spearman, "the common and essential element in the intelligences wholly coincides with the common and essential element in the Sensory Functions." 
     This fourth issue became a topic of controversy for Spearman, one which he would then learn to accept. 

     Spearman himself chose six events that he considered to be significant, these were:

  • Through the use of "g," there was now theoretical basis for Binet's way of designing tests. Spearman felt that there needed to be a clear relationship between theory and practice in order to get into the heart of 'mental test'.
  • Spearman brought the two ideas of general psychology and the psychology of individual differences together as one discipline. 
  • His development of the 'two-factor' theory of intelligence. This consisted of 'g' being general intelligence and 's' being task specific intelligence. This theory was further studied as Spearman came to realize the importance of 'broad factors'. 
  • Spearman's idea of 'g' was further supported by Karl Lashley's experiments with rats. The loss of cerebral tissue would cause rats to hinder specific functions, this supported Spearman's theory. 
  • The idea that 'g' and 's' compliment each other was an important discovery as was the results of experiments in formal training. Research shows that 'g' could not be improved through extensive use and that the outcome of training became habit. Furthermore, it was reported that these habits coincided with the idea of 's'. 
  • Spearman found that, 'considered qualitatively, 'g' manifested itself only in the noegenetic processes (but at the same time equally in all of them, in so far at least as they fell into the categories of relation and correlate eduction), and that therefore the 'g' saturation of any test or task was directly proportional to the extent that it demanded noegeneses (as distinct for instance from retentivity or from sensory or motor capacity).
     Of course Charles Spearman was founder of many more theories, but it was these six that he found great pride.

     One of Spearman's major applied achievements was that his theories were used to develop and support a system of examinations in England. These tests, the Plus-Elevens, were administered to British youngsters at age 11 and decisions about whether they attended university- or technical-oriented schools based upon these.

Published Works

     Throughout his many years of research and experiments Spearman published a number of articles and books. Included are: General Intelligence Objectivity Determined and Measured in 1904 considered a great landmark in the history of psychology. In 1927 came The Abilities of Man, then The Nature of Intelligence and the Principles of Cognition (1923) and Creative Mind (1931). Psychology Down the Ages (1937) was the final piece, in it was a complete account of main psychological theories from the beginning of time to his day.