The following is a guest post by Ruben Lopez, school psychologist with the Moreno Valley Unified School District, CA and member of the IQs Corner Virtual Community of Scholars.Ruben reviewed the following article and has provided his comments below.
- 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. History of Psychology, 11(2), 122-142 (click here to view)
After his retirement and late in life at age 68, what did Charles E. Spearman, discoverer of the general factor of human intelligence (symbolized as g), really think about general factor g? A recent article in the journal History of Psychology (complete citation above) addresses this question and concludes that Spearman’s long-standing adversaries Godfrey Thomson and Edward Thorndike proposed an incipient version of the CHC broad factors known as fluid (Gf) and crystallized (Gc). If Thomson and Thorndike indeed proposed an incipient non-hierarchical Gf-Gc versus Spearman’s hierarchical g, they began a debate which would continue more than 70 years later between CHC luminaries John Carroll (in support of hierarchical g) against John Horn (in support of non-hierarchical Gf-Gc)—a debate they waged until fairly recently to the end of both of their lives.
In their article, Deary, Lawn, and Bartholomew analyze word for word transcriptions of the contributions Spearman, Thomson, and Thorndike made to the theory and practice of testing intelligence at three meetings in 1931, 1935, and 1938 to which Spearman had been invited by Thorndike. Yet Deary, et al. report that Thorndike and Thomson found their interaction with Spearman to be negative and Spearman felt the same. Moreover, it seems to me that Deary, et al. clearly favored Thomson and Thorndike over Spearman’s contributions and personal style. Deary, et al., for example, describe Thomson as practical and winning, while Spearman in contrast is described as mechanically theoretical and a “contrarian”, waiting only to challenge and correct the theoretical views of the other participants.
Deary, et al. cite statements by Spearman that appear to indicate that he was uncertain or even disbelieved that g exists beyond being nothing more than a statistical phenomenon, as many anti-g proponents wish to communicate when they say that Spearman believed that g was just a “positive manifold.” Deary, et al., for example, suggest that supporters of g should know that at these meetings Spearman said about g, “There is no such thing, but only a general factor in intelligence.” (p. 126)
Yet at the same meeting Spearman said, “This than 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.” (p. 126) This says to me that Spearman as an objective researcher admitted that g was at least a psychometric fact but at the time was a phenomenon that was not understood in psychological or biological terms.
Therefore, this article convinced me that even as an old man, likely battle worn by younger adversaries like Thorndike and Thomson, Spearman did not appear to have abandoned g. In fact, one year after the last meeting with Spearmen at a symposium of the British Psychological Society in 1939, Godfrey Thomson is quoted in the article as saying, “I myself lean at the moment more toward Spearman’s g and his later group factors than I do to Thurstone’s….” (p. 129) Also, 69 years ago, Thomson conceded at the symposium, “Surely the real defense of g is simply that it has proved useful.” (p. 129)
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