Jensen was born August 24, 1923, to a father of Danish ancestry and a mother who was half Polish Jewish and half German. He studied at University of California, Berkeley (B.A. 1945), San Diego State College (M.A., 1952) and Columbia University (Ph.D., 1956), and did his doctoral thesis on the Thematic Apperception Test. From 1956 through 1958, he did his postdoctoral research at the University of London, Institute of Psychiatry.

Upon returning to the United States, he became a researcher and professor at the University of California, Berkeley, where he focused on individual differences in learning, especially the influences of culture, development, and genetics on intelligence and learning. He received tenure at Berkeley in 1962 and was given his first sabbatical in 1964. He has concentrated much of his work on the learning difficulties of culturally disadvantaged students. In 2003, he was awarded the Kistler Prize for original contributions to the understanding of the connection between the human genome and human society.

Jensen has had a lifelong interest in classical music and was, early in his life, attracted by the idea of becoming a conductor himself. At fourteen, he conducted a band that won a nationwide contest held in San Francisco. Later, he conducted orchestras and attended a seminar given by Nikolai Sokoloff. Soon after graduating from Berkeley, he moved to New York, mainly to be near the conductor Arturo Toscanini. He was also deeply interested in the life and example of Gandhi, producing an unpublished book-length manuscript on his life. During Jensen's period in San Diego he spent time working as a social worker with the San Diego Department of Public Welfare.

Jensen's interest in learning differences directed him to the extensive testing of black, Mexican-American, and other minority-group school children. The results led him to distinguish between two separate types of learning ability. Level I, or associative learning, may be defined as retention of input and rote memorization of simple facts and skills. Level II, or conceptual learning, is roughly equivalent to the ability to manipulate and transform inputs, that is, the ability to solve problems. Statistical analysis of his findings led Jensen to conclude that Level I abilities were distributed equally among members of all races, but that Level II occurred with significantly greater frequency among whites and Asian-Americans than among African-Americans and Mexican-Americans.

Later, Jensen was an important advocate in the mainstream acceptance of general intelligence factor, a concept which was essentially synonymous with his Level II conceptual learning. General intelligence factor, or g, is an abstraction that stems from the observation that scores on all forms of cognitive tests correlate positively with one another.

Jensen claimed, on the basis of his research, that general cognitive ability is essentially an inherited trait, determined predominantly by genetic factors rather than by environmental conditions. He also contended that while associative learning, or memorizing ability, is equally distributed among the races, conceptual learning, or synthesizing ability, occurs with significantly greater frequency in Asians than in whites. He suggested that from the data one might conclude that, on average, Asian Americans are more intelligent than white Americans.

Jensen's most controversial work, published in February 1969 in the Harvard Educational Review, was titled "How Much Can We Boost IQ 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, heritability of IQ was over 0.7 of the within-race IQ variability, and the 0.3 left over was due to non-shared environmental influences.

The work became one of...if not the most...cited papers in the history of psychological testing and intelligence research. It sparked a huge academic controversy. Although his paper was widely cited, a random selection of 60 of these citations revealed that 29 of the papers were direct rebuttals or criticisms of Jensen's arguments, 8 cited the paper as an "example of controversy," 8 used it as a background reference. Only 15 citations of Jensen's paper were in any way supportive of his theories, and 7 of these 15 were only in relation to minor points.

After the paper was released, students and faculty staged large protests outside Jensen's U.C. Berkeley office. Jensen was denied reprints of his work by his publisher and was not permitted to reply in response to letters of criticism...both extremely unusual 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).

Thomas Sowell wrote:

Professor Jensen pointed out back in 1969 that black children's IQ scores rose by 8 to 10 points after he met with them informally in a play room and then tested them again after they were more relaxed around him. He did this because "I felt these children were really brighter than their IQ would indicate." What a shame that others seem to have less confidence in black children than Professor Jensen has had.

However, Jensen's 1998 The Science of Mental Ability gives his position suggesting a genetic component is implicated in the white-black difference in IQ. 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.

In 1994 he was one of 52 signatories on "Mainstream Science on Intelligence," an editorial written by Linda Gottfredson and published in the Wall Street Journal, which declared the consensus of the signing scholars on the meaning and significance of IQ following the publication of the book The Bell Curve.

In 2005, Jensen's article, co-written with J. Philippe Rushton, named "Thirty Years of Research on Race Differences in Cognitive Ability", was published in the APA journal Psychology, Public Policy and Law. They present ten categories of evidence in support of the notion that IQ differences between whites and blacks are partly genetic in origin.

Melvin Konner wrote in the notes to his book The Tangled Wing: Biological Constraints on the Human Spirit:

Statements made by Arthur Jensen, William Shockley, and other investigators in the late 1960s and early 1970s about race and IQ or social class and IQ rapidly passed into currency in policy discussions. Many of these statements were proved wrong, but they had already influenced some policymakers, and that influence is very difficult to recant.

Many studies that purport to be both science-based and attempt to influence public policy have been accused of scientific racism. Konner wrote:

What of the latest currents of thought? Are they likely to lead to, or at least encourage, further distortions of social policy? The indications are not all encouraging. Richard Herrnstein and Charles Murray published a book in 1994 clearly directed at policy, just as Jensen and others had in the 1960s and 1970s. The Bell Curve: Intelligence and Class Structure in American Life (New York: Free Press, 1994) teamed a psychologist with a conservative policy advocate to try to prove that both the class structure and the racial divide in the United States result from genetically determined differences in intelligence and ability.

Their general assertions about genes and IQ were not very controversial, but their speculations on race were something else again.

Lisa Suzuki and Joshua Aronson of New York University wrote in 2005 that Jensen has largely ignored evidence that fails to support his position that IQ test score gaps represent a genetic racial hierarchy unwaveringly for over 30 years. During this time, Jensen has received more than one million dollars from the sometimes controversial Pioneer fund.

Paleontologist and evolutionary biologist Stephen Jay Gould, attacked Jensen's work in his 1981 book The Mismeasure of Man. Gould writes that Jensen misapplies the concept of "heritability", which is defined as a measure of the variation of a trait due to inheritance within a population (Gould 1981: 127; 156-157). According to Gould, Jensen uses heritability to measure differences between populations. Gould also 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 Charles Spearman. According to Gould, Jensen misunderstood the research of L. L. Thurstone to ultimately support this claim; Gould, however, argues that Thurstone's factor analysis of intelligence revealed g to be an illusion (1981: 159; 13-314). Gould criticizes Jensen's sources including his use of Catharine Cox's 1926 Genetic Studies of Genius, which examines historiometrically the IQs of historic intellectuals after their deaths (Gould 1981: 153-154).

In 1980 Jensen published a detailed book in defense of the tests used to measure mental abilities, entitled Bias in Mental Testing, in which he dropped the argument based on heritability. Reviewing this book, psychologist Kenneth Kaye endorsed Jensen's distinction between bias and discrimination. The purpose of tests is to discriminate (that is, reveal actual differences) on the basis of ability; bias constitutes error. Jensen defined any test as biased for a particular group if that group differs significantly from the majority group in the slopes, intercepts, or standard error of the estimates of their regression lines. Most studies found no difference in the regression lines between black and white groups, but those differences that had been found to be biased had overpredicted rather than underpredicted the minority group's performance (for example, grades in Officer Candidate courses). Jensen's conclusion:

Until we find out what the relevant psychological predictors are for which racial classification per se is merely a 'stand-in' variable, we have no choice but to include race (or other group membership) as a predictive variable along with the test scores or other predictive measures. On the other hand, if the overprediction of the minority group's criterion performance is not too extreme, it may seem reasonable to many to leave it uncorrected, thereby giving the benefit of the slight predictive bias to the presumably disadvantaged group.

Pointing out that "many of Jensen's opponents allowed their scientific conclusions to be far more biased by their political views than he did, Kaye quoted 18th-century David Hume: "There is no Method of Reasoning more Common, and yet none more blameable, than in philosophical Debates, to endeavor the Refutation of any Hypothesis, by a Pretext of its dangerous Consequences to Religion and Morality."

In a 1982 review of The Mismeasure of Man, Jensen gives point-by-point rebuttals to much of Gould's critique, including Gould's treatment of heritability, the "reification" of g, and the use of Thurstone's analysis. Gould responded to Jensen's rebuttals in a revised edition of the book, published in 1996.

In Arthur Jensen's response to Gould's criticisms, in the paper titled The Debunking of Scientific Fossils and Straw Persons., Jensen begins his paper with this observation

Stephen Jay Gould is a paleontologist at Harvard's Museum of Comparative Zoology and offers a course at Harvard entitled, "Biology as a Social Weapon." Apparently the course covers much the same content as does the present book. Having had some personal cause for interest in ideologically motivated attacks on biologically oriented behavioral scientists, I first took notice of Gould when he played a prominent role in a group called Science for the People and in that group's attack on the theories of Harvard zoologist Edward O. Wilson, a leader in the development of sociobiology...

While Jensen recognizes the validity of some of Gould's claims, in many places, he criticizes Gould's general approach

This charge of a social, value-laden science undoubtedly contains an element of truth. In recent years, however, we recognize this charge as the keystone of the Marxist interpretation of the history of science.

Jensen adds that Gould made a number of misrepresentations, whether intentional or unintentional, while purporting to present Jensen's own positions

In his references to my own work, Gould includes at least nine citations that involve more than just an expression of Gould's opinion; in these citations Gould purportedly paraphrases my views. Yet in eight of the nine cases, Gould's representation of these views is false, misleading, or grossly caricatured. Nonspecialists could have no way of knowing any of this without reading the cited sources. While an author can occasionally make an inadvertent mistake in paraphrasing another, it appears Gould's paraphrases are consistently slanted to serve his own message.

The g Factor

The g Factor: The Science of Mental Ability (1998) is considered by supporters to be Jensen's magnum opus on the general intelligence factor (g). The book deals with the intellectual history of g and various models of how to conceptualize intelligence, and with the biological correlates of g, its heritability, and its practical predictive power.

Clocking the Mind

Clocking the Mind : Mental Chronometry and Individual Differences (2006) deals with mental chronometry (MC), and covers a variety of techniques for measuring the speed with which the brain processes information. Whereas IQ merely represents an interval (ranking) scale and thus possesses no true ratio scale properties, Jensen argues mental chronometry represents a true natural science of mental ability.

Interviews

• SASP Interviews: Arthur R. Jensen. Beaujean, A. A. (2002, July). SASP News, 2 (4). (pdf)
• "A Conversation With Arthur Jensen (Part 1)". (1992). American Renaissance, 3(8).
• "A Conversation With Arthur Jensen (Part 2". (1992). American Renaissance, 3(9).
• Intelligence, Race, and Genetics: Conversations with Arthur R. Jensen. (2002) Frank Miele (of Skeptic Magazine). Westview Press. ISBN 0-8133-4008-X

Selected articles, books, and book chapters

• Rushton, J. P., & Jensen, A. R.. (2005). Thirty years of research on Black-White differences in cognitive ability. Psychology, Public Policy, & the Law, 11, 235-294. ( pdf)
• Rushton, J. P., & Jensen, A. R. (2005). Wanted: More race-realism, less moralistic fallacy. Psychology, Public Policy, and Law, 11, 328-336. ( pdf)
• Rushton, J. P., & Jensen, A. R. (2003). African-White IQ differences from Zimbabwe on the Wechsler Intelligence Scale for Children-Revised are mainly on the g factor. Personality and Individual Differences, 34, 177-183. ( pdf)
• 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.