Arthur Jensen is an American educational psychologist, born August 24, 1923 and educated at the University of California, Berkeley (B.A. 1945), San Diego State College (M.A., 1952) and Columbia University (Ph.D., 1956). Jensen was a major practitioner of individual differences psychology with a special interest in intelligence and the nature versus nurture debate, and argued strongly that intelligence is partially heritable (see g theory).

Controversial work

Jensen's most controversial work, published in February 1969 in the Harvard Educational Review, was titled "How Much Can We Boost I.Q. and Scholastic Achievement?" It concluded, among other things, that "head start" programs designed to boost African-American IQ scores had failed, and that this was likely never to be remedied, largely because, in Jensen's estimation, over 70% of the within race IQ variability was due to genetic factors, and the 30% left over was due to non-shared environmental influences (e.g., prenatal drug exposure, placental nutrient competition when there are multiple births).

When the work was initially published, students and faculty staged large, loud protests outside his University of California, Berkeley office, and he received multiple death threats. He was even denied reprints of his work by his publisher and was not permitted to reply in response to letters of critism -- both extremely unusual and exceptional policies for their day. Many colleagues at the time felt that even if Jensen's work contained no scientific merit, his treatment was itself against the spirit of science and the free exchange of ideas.

In a later article, Jensen argued that his claims had been misunderstood:

...nowhere have I "claimed" an "innate deficiency" of intelligence in blacks. My position on this question is clearly spelled out in my most recent book: "The plain fact is that at present there exists no scientifically satisfactory explanation for the differences between the IQ distributions in the black and white populations. The only genuine consensus among well-informed scientists on this topic is that the cause of the difference remains an open question" (Jensen, 1981a, p. 213).

Nevertheless, eugenicists and others point to passages such as the following (from his book The g Factor: The Science of Mental Ability) to support their claim that Jensen has proven that differences in IQ scores between races are mostly genetic:

In Chapter 12: Population Differences in g: Causal Hypotheses, Jensen writes: "The relationship of the g factor to a number of biological variables and its relationship to the size of the white-black differences on various cognitive tests (i.e., Spearman's hypothesis) suggests that the average white-black difference in g has a biological component. Human races are viewed not as discrete, or Platonic, categories, but rather as breeding populations that, as a result of natural selection, have come to differ statistically in the relative frequencies of many polymorphic genes. The genetic distances between various populations form a continuous variable that can be measured in terms of differences in gene frequencies. Racial populations differ in many genetic characteristics, some of which, such as brain size, have behavioral and psychometric correlates, particularly g."

Paleontologist Stephen Jay Gould, known for his popularizations of science in mass market books and magazines, attacked Jensen's work in his 1981 book The Mismeasure of Man.

Gould makes three criticisms. The first is the criticism most commonly leveled against Jensen by other anthropologists and biologists: that Jensen misunderstands the concept of "heritability." Heritability measures the percentage of variation of a trait due to inheritance, within a population. Jensen, however, has used the concept of heritability to measure differences in inheritance between populations (Gould 1981: 127; 156-156).

The second criticism is relatively minor: Gould disagrees with Jensen's support of the attempts of others to calculate the IQ of dead people (such as the famous Polish astronomer and Prussian monetary theorist Copernicus) (1981: 153-154).

The third criticism is significant: Gould disagrees with Jensen's belief that IQ tests measure a real variable, g, or "the general factor common to a large number of cognitive abilities" which can be measured along a unilinear scale. This is a claim most closely identified with Cyril Burt and Charles Spearman. According to Gould, Jensen misunderstood the research of L. L. Thurstone to ultimately support this claim; Gould however argues that Thurstone's factoral analysis of intelligence revealed g to be an illusion (1981: 159; 13-314).

In a 1982 review of Gould's book Jensen gives point by point rebuttals to Gould's characterizations of his work, including Gould's treatment of heritability, the "reification" of g and the use of Thurstone's analysis (see [1] (http://www.wcotc.com/euvolution/articles/gould01.html) or [2] (http://www.debunker.com/texts/jensen.html)). Gould's responses can be found in the latest edition of The Mismeasure of Man (1996).

See also: the discussion of race and intelligence.

Further Reading

Interviews

Beaujean, A. A. (2002, July). SASP Interviews: Arthur R. Jensen. SASP News, 2 (4). (pdf (http://www.missouri.edu/~aab2b3/SASP-Su2002.pdf))

A Conversation With Arthur Jensen (Part 1). (1992). American Renaissance, 3(8). (http (http://www.amren.com/928issue/928issue.html))

A Conversation With Arthur Jensen (Part 2). (1992). American Renaissance, 3(9). (http (http://www.amren.com/929issue/9209issue.html))

Selected Articles & Book Chapters

Rushton, J. P., & Jensen, A. R.. (in press). Thirty years of research on Black-White differences in cognitive ability. Psychology, Public Policy, & the Law.

Jensen, A. R. (2002). Galton's legacy to research on intelligence. Journal of Biosocial Science, 34, 145-172.

Jensen, A. R. (2002). Psychometric g: Definition and substantiation. In R. J. Sternberg, & E. L. Grigorenko (Eds.). The general factor of intelligence: How general is it? (pp. 39-53). Mahwah, NJ, US: Lawrence Erlbaum.

Jensen, A. R. (2000). Testing: The dilemma of group differences. Psychology, Public Policy, & Law, 6, 121-128.

Jensen, A. R. (1998) The g factor and the design of education. In R. J. Sternberg & W. M. Williams (Eds.), Intelligence, instruction, and assessment: Theory into practice. (pp. 111-131). Mahwah, NJ: Lawrence Erlbaum.

Jensen, A. R. (1996). Giftedness and genius: Crucial differences. In C. P. Benbow, & D. J. Lubinski (Eds), Intellectual talent: Psychometric and social issues (pp. 393-411). Baltimore: Johns Hopkins University.

Jensen, A. R. (1995). Psychological research on race differences. American Psychologist, 50, 41-42.

Jensen, A. R. (1993). Spearman's g: Links between psychometrics and biology. In F. M. Crinella, & J. Yu (Eds.), Brain mechanisms: Papers in memory of Robert Thompson (pp. 103-129). New York: Annals of the New York Academy of Sciences.

Jensen, A. R. (1993). Why is reaction time correlated with psychometric g? Current Directions in Psychological Science, 2, 53-56.

Jensen, A. R. (1989). The relationship between learning and intelligence. Learning and Individual Differences, 1, 37-62.

Kranzler, J. H., & Jensen, A. R.(1989). Inspection time and intelligence: A meta-analysis. Intelligence, 13, 329-347.

Jensen, A. R. (1974). Ethnicity and scholastic achievement. Psychological Reports, 34, 659-668.

Jensen, A. R. (1974). Kinship correlations reported by Sir Cyril Burt. Behavior Genetics, 4, 1-28.

External links

• The London School of Differential Psychology: Arthur R. Jensen (http://www.individualdifferences.info/LondonJensen.htm)
• Powerpoint presentation of Jensen's biography (http://www.missouri.edu/~aab2b3/JensenPresentation.ppt)