Monday, 9 November 2015
The Wissler Controversy
And don't we all like a bit of scandal? What was this about?
Clark Wissler (1870-1947) is best known today as an influential American anthropologist, but his early training was in psychology. His 1901 doctoral dissertation created an academic uproar by purportedly debunking some of the most influential intelligence theories of the time. The controversy was made scandalous by the fact that Wissler's findings discredited the research of his mentor, James McKeen Cattell. (Fancher, 1985, p. 48-49) To appreciate the iconoclastic nature of the Wissler controversy, it is necessary to understand the importance of the research of two notable men who proceeded him: Francis Galton and James McKeen Cattell. Francis Galton (1822-1911) was a believer in the hereditary basis of intelligence, and is credited with popularizing the phrase "nature and nurture." He originated and named the eugenics movement, in service of which he created the basic idea of the intelligence test. (It is important to note however, that the term "intelligence test" did not come into being until later.) (Fancher, 1985) Galton believed that intelligence was a matter of neurological efficiency. Therefore, he theorized that it could be tested by measuring reaction time and sensory acuity. In the mid 1880s he established an anthropometric laboratory at London's South Kensington Museum, cleverly enticing visitors to spend three pence apiece to enjoy the novelty of undergoing a variety of psychophysical tests. Besides providing amusement for the museum's patrons, this unusual laboratory provided a vast amount of research data. (Fancher, 1985, pp. 36-37; Sternberg, 1990, p. 70-71) At about the same time, an American doctoral student, James McKeen Cattell (1860-1944) was conducting a series of reaction time experiments in Germany. When he became aware of Galton's anthropometric laboratory, he began to correspond with him, and designed a series of 50 psychophysical tests based on Galton's earlier work. He established his own anthropometric laboratory at Cambridge University, and became a successful international advocate of the psychophysical approach to mental testing. (Fancher, 1985, pp. 45-47) The work of these two men was of pivotal importance to the field of experimental psychology. Psychophysical testing had great popular appeal, and was being enthusiastically embraced by researchers from many different countries. (Fancher, 1985, pp. 47-48)
It is rare for a graduate student to single-handedly crush the morale of the professional establishment, but that is exactly what Clark Wissler did. At the time of his doctoral dissertation, Wissler was one of Cattell's graduate students at Columbia University. He obtained the psychophysical test scores from several hundred Columbia University and Barnard College students who had been Cattell's research subjects. He then used the newly perfected Pearson correlation coefficient to examine the relationship between each student's score on each of the tests and their undergraduate academic grades. The surprising result was that there was virtually no correlation between scores on Cattell's tests and academic achievement. Perhaps equally surprising was the fact that scores on Cattell's tests did not even appear to correlate with each other. Since the tests didn't agree among themselves, and they didn't correlate with independent measures of mental ability (undergraduate academic grades), it did not seem possible that they could be valid measures of intelligence. (Fancher, 1985, pp. 48-49; Sternberg, 1990, pp. 72-73)
Impact of Wissler's Dissertation
At the time of Wissler's dissertation, psychophysical measurement was the primary research paradigm for intelligence testing. The eugenics movement was gaining momentum, and the majority of the psychological community was thoroughly invested in the findings of Galton and Cattell. After Wissler's results became known, psychology gradually lost interest in psychophysical testing. Although Cattell remained a psychologist, he also became disenchanted with psychophysical testing, and spent the remainder of his career in relative obscurity. (Fancher, 1985, p. 49) Galton continued to be interested in eugenics and hereditary theory until he died in 1911. (Fancher, 1985, p. 82) Many critics have pointed out that Wissler's research was flawed. When Charles Spearman first heard of the dissertation, he was disheartened. However, he soon realized that there was a degree of unreliability in Cattell's sensory discrimination scores. Therefore, Wissler's correlation coefficients would have underestimated the degree of the relationships between variables. Spearman believed that applying a correction formula to the original data would allow the true degree of relationships to be assessed. (Fancher, 1985, pp. 88-89) Other critics have argued that even if Wissler's correlations were correct, the inferences based on his results were not. Wissler's research subjects were members of a very homogeneous group, i.e., undergraduate students from prestigious universities. Since these students were relatively similar to one another, correlations would be expected to be lower than those obtained from a more heterogeneous group. (Sternberg, 1990, pp. 73-74)
Later Career of Wissler
Almost immediately after his iconoclastic upheaval (and perhaps in part because of it) Wissler abruptly changed fields. (Fancher, 1985, pp. 48-49) Although he always maintained an avuncular interest in psychology, most of what is written about him today refers to his long and prolific career in anthropology. In 1902 he became an assistant in Ethnology at the American Museum of Natural History in New York--a position that eventually spawned his appointment as Curator. During this period he became enthusiastically involved in anthropological fieldwork, focusing his energies on the culture and customs of Native Americans. He lectured at Columbia and Yale, wrote dozens of books and articles, and contributed a sizable amount of ethnographic data to the field of anthropology. (Freed & Freed, 1993) Although Clark Wissler left the field of psychology behind a century ago, psychology has not left him behind. His doctoral dissertation permanently changed the dominant research paradigm for intelligence testing. (Fancher, 1985, p. 49) Although advances in neurophysiology may eventually impact intelligence testing, anthropometric testing (as it was conceived by Galton, Cattell, Wissler and others) is rarely used today.
Fancher, R.E. (1985). The intelligence men: Makers of the IQ controversy. New York: W.W. Norton & Company.
Freed, S.A., & Freed, R.S. (1992). Clark Wissler. In P.H. Raven (Ed.), National Academy of Sciences of the United States of America Biographical Memoirs, 61, 468-497. Washington D.C.: National Academy Press.
Sternberg, R.J. (1990). Metaphors of mind: Conceptions of the nature of intelligence. Cambridge: Cambridge University Press.