Arthur R(obert) Jensen was born August 24, 1923, in San Diego, and died on October 22, 2012, in his home in Kelseyville in northern California at the age of 89. At the time of his death he was Professor Emeritus of the University of California (Berkeley), in whose Department of Educational Psychology he had served since his initial academic appointment in 1958.
Three events shaped his intellectual career. In 1956, after receiving a PhD from Columbia University (his dissertation was on the ineffectiveness of a particular projective test in predicting aggression), Jensen spent two postdoctoral years in H. J. Eysenck's laboratory in London, where he was exposed to the psychometric, genetic, and individual difference traditions stemming from Galton, Pearson, and Spearman. Spearman's notion of g, the common factor in performance on diverse cognitive tasks, became in particular a lifelong guiding interest of Jensen's. The second critical event was a year at the Center for Advanced Study in the Behavioral Sciences in Palo Alto, California, in 1966–67, where discussions with a geneticist steered Jensen into the behavior genetics literature.
The third critical event was the publication in the Harvard Educational Review in 1969 of his famous (or infamous) 123-page article entitled ‘How much can we boost IQ and scholastic achievement?’ Jensen concluded that it is not easy to boost them much: his opening sentence was: ‘Compensatory education has been tried and it apparently has failed’ (p. 2). This was bad enough, but what really put the fat in the fire was Jensen's raising the possibility that the persistent deficit of US blacks in performance in the classroom and on IQ tests might have a genetic component. After mentioning various lines of evidence, Jensen called it a ‘not unreasonable hypothesis that genetic factors are strongly implicated in the average Negro-white intelligence difference’, although he hastened to add that this ‘does not exclude the influence of the environment or its interaction with genetic factors’ (p. 82). He was also careful to label this not as a proven fact, but as a hypothesis worthy of further investigation. ‘The fact that a reasonable hypothesis has not been rigorously proved does not mean that it should be summarily dismissed. It only means that we need more research for putting it to the test’ (p. 82).
Jensen's views received wide publicity and were anathema in many intellectual circles. Radical groups disrupted his public lectures. Students chanted outside his classroom: Dr. Jensen is inside. He is teaching genocide. His car tires were slashed. He received death threats against himself and his family. For a period, the university provided him with a pair of bodyguards when he moved about campus, and the police X-rayed his mail before he was permitted to open it. The London Daily Mail once labeled him ‘The world's most loathsome scientist’. (The history of this period is recounted in interviews by Miele, Reference Miele2002 and Robinson & Wainer, Reference Robinson and Wainer2006; in the preface to Jensen, 1972; and in Pearson's Race, Intelligence and Bias in Academe, Reference Pearson1991).
All this began with a boyhood in San Diego, in which young Jensen's chief hobbies were collecting snakes and playing the clarinet. He was exceptionally gifted at the latter, playing second clarinet with the San Diego symphony for a year when he was 17, and at one point contemplated a career as an orchestra conductor. He decided instead on the academic life, but retained a lifelong fondness for classical music. After receiving his BA from Berkeley in psychology, and while pursuing his MA at San Diego State College, his experience was broadened by various jobs: work in the family lumber business; stints as a lab technician, a social worker, and a high school orchestra conductor and biology teacher (Miele, Reference Miele2002).
After his London postdoctoral years, his academic life at Berkeley started quietly with a series of studies on the serial position effect in rote learning, although even here he was beginning to explore such matters as individual and group differences in the skewness of the serial position curve. Then came the Harvard Educational Review paper. In addition to the brief discussion of race differences, the paper emphasized the ubiquity of individual differences in learning and the importance of devising an educational system responsive to the different ways in which different individuals learn; the centrality of g; its large genetic loading; and the substantial role of biological factors in the environmental influences upon intelligence.
Although Jensen's list of publications includes many items devoted to setting one critic or another straight, he also produced a very substantial body of empirical work on individual and group differences. For example, he did a number of studies with reaction times and other elementary cognitive tasks, showing average group differences in performance (more rapid in the order of blacks, whites, Asian Americans) and a relationship of performance to g within and between groups. He also did interesting work with IQ tests. For instance, he showed that the difference in performance between black and white children strongly resembled an age difference as opposed to a cultural difference. That is, older black children's responses tended to resemble younger white children's responses with respect to which items were easier or harder, the kinds of errors made, and so on.
Jensen's work became the subject of a number of books and special journal issues. For example, The Harvard Educational Review published an issue (Spring, Reference Jensen and Jensen1969) in which a number of individuals from different disciplines commented on Jensen's article and he responded. S. Modgil and C. Modgil edited a volume, Arthur Jensen: Consensus and Controversy (Reference Modgil and Modgil1987), in which a variety of different points of view, some favorable, some hostile, were expressed. A special issue of the journal Intelligence (Detterman, Reference Detterman1998) was entitled ‘A king among men: Arthur Jensen’ and provided mostly laudatory comments from a number of distinguished intelligence researchers and behavior geneticists. A variety of (mostly positive) sentiments and a 438-item bibliography of Jensen's publications to date appeared in The Scientific Study of General Intelligence: Tribute to Arthur R. Jensen (Nyborg, Reference Nyborg2003).
Jensen himself was the author of a number of books, including Educability and Group Differences (Reference Jensen1973), a follow-up to the Harvard Educational Review article; Bias in Mental Testing (Reference Jensen1980), discussing the psychometric issues and concluding that IQ tests predict with equal accuracy for US whites and blacks; The g Factor: The Science of Mental Ability (Reference Jensen1998), a scholarly 648-page discussion of the topic; and Clocking the Mind: Mental Chronometry and Individual Differences (Reference Jensen2006), describing his early work with reaction times and later work by himself and others using various elementary cognitive tasks to address issues in the study of intelligence.
And what did Jensen have to say about his own life? In a late interview (Robinson & Wainer, Reference Robinson and Wainer2006, p. 337) he said: ‘. . . as far as I can tell, my motivation and pleasure have been simply doing what I can for the scientific advancement of differential psychology. That's about it, along with a little good music.’
