Honoring an IQ Iconoclast
The Scientific Study of General Intelligence
Tribute to Arthur R. Jensen
(Ed.) Helmuth Nyborg
New York: Pergamon, 2003
Reviewed by Kevin Lamb
Scan the shelves in the psychology section of Borders, Barnes and Noble, or any major retail bookseller and one will find scores of titles by Jung, Freud, Robert Sternberg, Howard Gardner, Steven Pinker, Daniel Goleman, Anthony Robbins, Jerome Kagan, John Gray, James Hillman, Dr. Phil, and Laura Schlesinger. Â Itâ€™s not unusual to find a well-stocked psychology section in a quality bookstore; what is unusual is finding quality amidst this quantity: substantially solid books that challenge politically correct orthodoxy.Â From the serious to the sublime, a reader can find books on psychoanalysis, addictions, relationships, personality theory, educational psychology, testing, and history of psychology, not to mention the more voluminous pop-psych and self-help themes.
The Bell Curve was a departure from this literary sub-cultureâ€”a rarity that maintains a lasting market value given its steady appeal as a runaway controversial bestseller. The hostile reception that the bookâ€™s high-profile launch received upon publication generated widespread interest, especially after hostile reviewers unleashed a barrage of scathing critiques and ad hominem attacks on the bookâ€™s authors, Richard Herrnstein and Charles Murray. (The Bell Curve is still available in quality paperback on retail bookstore shelves nearly a decade after the publication of its first-edition hardcover.) However, the bulk of psychology titles that major retail bookstores stock and promote are dominated by a politically correct uniformity that either avoids such â€œdivisiveâ€ issues as racial differences in IQ (pretending that these differences are merely cosmetic) or bolsters racial egalitarianism by attributing these differences to environmental (non-biological) causes.Â Scholarly books that deviate from this politically correct genre are usually published by vanity mail-order publishers and therefore ignored by the major book reviewer periodicals, such as the New York Review of Books, New Yorker, or Times Literary Supplement.Â Try finding a copy of Arthur Jensenâ€™s The g Factor or Richard Lynn and Tatu Vanhanenâ€™s IQ and the Wealth of Nations in a retail bookstore.
Helmuth Nyborgâ€™s The Scientific Study of General Intelligence, an edited collection of tributes to the work of Arthur R. Jensen, is the most recent work of substance to fail the big chainsâ€™ litmus test of political correctness. Students of IQ will either have to order it directly from the publisher, Elsevier-Pergamon, or from amazon.com. Although the price is quite steep, the book is well worth the investment. Nyborg brings together a treasure trove of contemporary research findings from leading experts on a range of issues that emphasize the importance of general intelligence, including the views of a few skeptics of Jensenâ€™s work. The contributors to this festschrift span the full range of Jensenâ€™s research interests and experiences as a pioneer in differential psychologyâ€”primarily behavioral geneticists who examine the interface between nature and nurture on a variety of physical and behavioral traits. In essence, differential psychologists who analyze the heritability of traits in populations.
When one considers the full scope and magnitude of Jensenâ€™s scholarship, including the quality of his work over a remarkable and tumultuous career, it isnâ€™t too surprising to find that his own colleaguesâ€”fellow academics who know him quite well, including respectable critics who disagree with Jensenâ€”hold him in high esteem.Â In a survey of 1,725 members of the American Psychological Society that solicited the top 100 psychologists of the twentieth century (published in the July/August 2002 Review of General Psychology), Jensen ranked no. 47.Â This evaluation is at odds with the portrayal that Jensenâ€™s detractors have successfully cultivated in the mass media over the years.Â Consider the following headline of a Daily Mail article from September 17, 1999, that covered Jensenâ€™s visit to London: â€œIs This Man Truly the Worldâ€™s Most Loathsome Scientist?â€ The article went on to identify Jensen as â€œthe worldâ€™s most demonized scientistâ€: a typical example of the sort of press coverage Jensen has received over the years.
Yet compare the manufactured image of Jensen the academic â€œracistâ€ with the regard in which the Berkeley psychologist is held by many of those who studied under him.Â Philip A. Vernon, professor of psychology at the University of Western Ontario, writes about the influences that Jensen had in shaping his graduate work:
As a research advisor, Arthur was the perfect model. His own research is methodologically rigorous and is incredibly productive. He allowed me (and the other students working with him at that time) considerable freedom in choosing research topics, but he was also always available for consultation and advice when needed. Through his own example, I know that he brought out the best in me, and I have continued to value his comments and suggestions on work-in-progress ever since. I also valued Arthurâ€™s willingness to tackle topics that, due to their controversial nature, often led to his being criticized, and sometimes demonstrated against and even physically attacked. He was a staunch believer that knowledge is always preferable to ignoranceâ€”no matter what the topicâ€”and he never allowed the opinions of others to stop him from doing what he believed in: this was a lesson well worth learning.
Another former graduate student, Steven M. Paul, a faculty member at the University of Californiaâ€“San Francisco, recalls his experiences with Professor Jensen:
Honesty, integrity, and accuracy, these are the words that first come to mind when I reflect on my impressions of Dr. Arthur Jensenâ€¦. I was lucky enough to serve as his research assistant for many years. I learned more from our private conversations and work together than from the many formal courses I have taken over the yearsâ€¦. Although his academic standards and accomplishments are perhaps the first things that come to mind, I also remember how impressed I was with his humanity and nonacademic pursuits.Â Arthur Jensen is a true man of the world. His interests, skills, and passions are astounding.
Several other testimonials by former graduate students offer a more complete picture of Jensen as a first-rate instructor, mentor, and advisor. The fact that he has managed to persevere in the face of death threats, classroom brawls, on-campus police escorts, cancelled lectures, stringent peer-review standards, and unexplained book cancellations by publishers attests to Jensenâ€™s stamina and resilience in his quest to resolve unanswered difficult questions that most would otherwise avoid. The average scholar would have been driven into more vocationally acceptable avenues of research that would have guaranteed a smoother career path. Â Jensenâ€™s diligence, exemplified in his 1969 Harvard Educational Review article, â€œHow Much Can We Boost IQ and Scholastic Achievement?â€ would have been a steppingstone to fame and prominence if the topic had been anything other than racial and genetic differences in intelligence. The fact that it triggered a cascade of death threats, protests, postponed lectures, and negative publicity that continues to this day speaks volumes about the issue of media bias and managed news. Do we really value a society that fosters ideological myths (human equality) at the expense of empirically corroborated truths (human differences)? Are college-educated adults simply incapable of assessing or uninterested in deciphering the empirical realities about the genetic and racial correlates of intelligence?
John Carroll, professor emeritus at the University of North Carolina, Chapel Hill, perhaps the foremost authority on factor analytic studies of cognitive abilities, explores the evidence for the general or g factor in a definitive chapter on the nature of g and its relationship with lower-level cognitive abilities. The debate among IQ authorities that has consumed much time and energy since Charles Spearmanâ€™s pioneering 1904 paper on general intelligence is whether the concept of intelligence is a single unified factor, a nexus of broad specialized abilities, or whether the term represents an uncorrelated composite of smaller, independent abilities.
To the layman this may seem to be the latter-day equivalent of determining how many angels actually dance on the head of a pin, but to scores of researchers over the years this question has shifted from one position to the next, depending, as Carroll points out, on how the analysis of the research has been conducted. His own research, published in a landmark 1993 study, Human Cognitive Abilities, accepts what he refers to as the â€œstandard multifactorial view.â€ It recognizes â€œthe existence of a general factor and of a series of non-general â€˜broadâ€™ factorsâ€ in a hierarchical three-level stratum.Â Some researchers reject the idea that a general factor can be extracted from a lower stratum of cognitive abilities, but as Carroll explains, the evidence to date from known datasets of empirical studies points to the existence of a general factor, although he adds that the jury is still out in terms of reaching a definitive conclusion because, in his own view, there isnâ€™t enough objective evidence to settle this dispute once and for all. Â Jensenâ€™s monumental 1998 study The g Factor has decisively tipped the scales toward the conventional psychometric view.
Robert Plomin, a leading behavioral geneticist with the Institute of Psychiatry in London, highlights the genetics of intelligence in a chapter that explains Jensenâ€™s contributions to this field, the important discoveries that are currently coming to the fore, and the pitfalls that Plomin and others have encountered at the molecular research level.Â Developing technologies that augment this later area of genetic research are making it easier to identify and scan DNA markers.Â As to Jensenâ€™s contributions to this area of study, Plomin explains that:
Although a review of behavioral genetic research on g was published in Science in 1963 (Erlenmeyer-Kimling & Jarvik 1963), it was Arthur Jensenâ€™s Harvard Educational Review monograph (Jensen 1969) that made it no longer possible to avoid the issue in the social and behavioral sciences. He clearly and carefully described quantitative genetic theory with a minimum of jargon, reviewed the data, and concluded that individual differences in IQ scores are substantially due to genetic differences. The section of the monograph entitled â€œThe inheritance of Intelligenceâ€ (pp. 28-59) is still one of the best introductions to the genetics of g.
Contributors Richard Lynn and J. Philippe Rushton scrutinize the evidence for racial differences in g.Â Lynn considers the geographic and racial parallels to regional IQ patterns in populations around the world. He notes that â€œ[T]his association between intelligence and race is sufficiently close for it to be possible to predict the approximate IQs of nations and of sub-populations within nations from their racial identity.â€ Lynn explains the significance of these global IQ data:
The studies surveyed in this chapter show that the IQs of the worldâ€™s populations vary consistently with their race.Â There is no environmental theory that can explain this.Â The only conclusion that can be drawn from this association is that race is the most important determinant of the IQs of populationsâ€¦.
With regard to the intelligence differences between blacks and whites in the United States, the consistency of the black-white differences worldwide corroborates the thesis that genetic factors are largely responsible for the difference in the United States.Â We have seen that whites from North West Europe, which is where the ancestors of most American whites came from, almost invariably have IQs close to 100, whether they are in Europe, Canada, Australia, New Zealand, or South Africa, while blacks in sub-Saharan Africa invariably obtain IQs in the range of 62-78.Â The IQ of blacks in the United States is around 85 and hence substantially higher than the IQs of blacks in sub-Saharan Africa.Â There are two explanations for this.Â The first is that American blacks are a hybrid population with about 25% of white ancestry (Reed 1969; Chakraborty et al. 1992).Â According to genetic theory this would raise their IQs above the level of blacks in Africa.Â The second is that American blacks live in a society run by whites and enjoy much higher standards of living, nutrition, education and health care than they have in societies run by blacks.Â This enriched environment can be expected to have some advantageous impact on their IQ. When we look at the IQs of blacks in Africa we have to conclude that living in a white society has raised rather than lowered the IQs of American blacks.
Rushton traces Jensenâ€™s methodology in reevaluating the essence of the 15-18 point black-white IQ difference. Jensenâ€™s theoretical concept of intelligence shifted from his Level I-Level II abilities to Spearmanâ€™s general factor of intelligence after re-reading Spearmanâ€™s work, especially his 1927 classic The Abilities of Man.Â Conceptually the g factor provided a better, more comprehensive explanation for the racial differences in intelligence. In 1985, Jensen published an influential paper in Behavioral and Brain Sciences, which reviewed the data from major comparative studies on the black-white IQ gap. His analysis shifted to Spearmanâ€™s g factor as an explanation for this well-established IQ differential. Jensen found that the black-white intelligence difference was more pronounced on IQ tests that had a greater g-loading across the mental tasks on various tests. Rushton elaborates on the evolution of his own research, taking up the gauntlet and discovering additional physical and behavioral correlates that further confirm the genetic hypothesis of the black-white gap. In an impressive summary of the evidence to date, Rushton believes that researchers are gradually accepting Jensenâ€™s â€œdefault hypothesisâ€ as an explanation for racial differences in g primarily because â€œJensen has gone beyond proving the statistical reality and predictive validity of the general factor.â€
Aside from the more personal aspects of Jensenâ€™s own struggles against the forces of political correctness, the balance of the festschrift addresses the societal consequences that the g factor can exert in a variety of applied circumstances. Linda Gottfredson, a psychologist at the University of Delaware, reviews the literature on the importance of g in the workplace. The g factor remains the single best predictor of job performance in the workplace and offers a useful tool for human resource and personnel departments in making decisions over hiring and promotions.Â She extrapolates the mounting data in personnel psychology and applies the lessons to situations in everyday life. Another chapter by Anthony Walsh and Less Ellis describes the shift in thinking among criminologists to recognize the predictive validity of IQ in criminality.Â This is another area in which early psychological pioneers, such as H. H. Goddard, reviewed the evidence and found a strong correlation between low average intelligence levels and recidivist criminal conduct.
One of the more interesting chapters assesses the practical and legal implications of rival concepts of intelligence for employee selection. Despite the media fascination with relatively untested theories such as Golemanâ€™s â€œemotional intelligence,â€ Howard Gardnerâ€™s â€œmultiple intelligences,â€ and Sternbergâ€™s â€œpractical intelligence,â€ the empirical void that these theories have failed to fill and the lack of credible solid evidence to substantiate these largely unproven assumptions, the authors conclude, would not hold up in court when challenged in an adverse-impact discrimination law suit.Â The court has established what are known as the â€œDaubert Standardsâ€ for granting the admissibility of scientific evidence. The criteria were set forth in Daubert v. Merrell Dow Pharmaceuticals (1993):
The authors demonstrate the legal hurdles that these rival intelligence theories must cross if their widespread use is deemed to be useful in selecting qualified personnel while simultaneously minimizing adverse impact toward minority applicants.Â Even though a combination of personality tests and non-conventional IQ tests may theoretically lower the degree of adverse impact and increase the validity of the combined screening measures, the applied experience has led to mixed resultsâ€”lower adverse impact in some cases and higher in others. The problem still remains: the track record has yet to produce a valid alternative to established general ability or IQ tests, which would be equally valid as a reliable measure of intelligence and, in their widespread use, reduce adverse impact in employment selection.
Over the years, Jensenâ€™s critics, especially in the media, have dismissed his research findings, to put it more charitably, as those of an eccentric crank with a social-policy ax to grind.Â Such a simplistic and erroneous view overlooks not only his own record of maintaining a straightforward adherence to objective scientific analysis, and a meticulous degree of thoroughness in carrying out his responsibilities as a researcher, but also fails to apply the same standards of skepticism and scrutiny to critics of g who are pushing their own egalitarian social agenda. Â Recently I picked up, second-hand, one of the more â€œscholarlyâ€ critiques of The Bell Curve, a book co-authored by six faculty members in the sociology department at the University of California-Berkeley and published by Princeton University Press in 1996, titled Inequality By Design: Cracking the Bell Curve Myth.Â It received some reviews in the popular press at the time of its publication, including a glowing account of the authors in the San Francisco Chronicle that lauded Inequality By Design for â€œattack[ing] The Bell Curve authorsâ€™ data analysis, not just their motives or conclusions.â€Â I couldnâ€™t help but notice the inscription on the front flyleaf by one of the bookâ€™s co-authors: â€œMay these words aid you in the struggle for social justiceâ€”Samuel R. Lucas.â€ Nothing like objectivity!
The author is the editor of The Occidental Quarterly and Race, Genetics & Society: Glayde Whitney on the Scientific and Social Policy Implications of Racial Differences (Scott-Townsend).