The Half-Full glass

The g Factor: the Science of Mental Abilities, Arthur R. Jensen, Westport, CN: Praeger, 1998, 648 p.p., $39.95

reviewed by Steve Sailer

This was written at the request of National Review, but then they turned it down. 
For scientists working in the paradoxical discipline of individual differences in mental abilities, these are the best of times. They've confirmed that performances on all mental tests are positively correlated: If Al outscores Bert on the first assignment (say, vocabulary or reaction-times), bet on Al in the next test, no matter how dissimilar (e.g., math, paper-folding, or distinguishing musical pitches). This pervasive correlation is why a crude one-number IQ score is so implausibly useful, rivaling a "conscientiousness" rating as the best single predictor of a host of real world consequences. Lurking behind IQ is a "general factor" or "g" that plays a role (of varying magnitudes) in the accomplishment of any and every mental task, from taking a test to making a living.

Even more strikingly, these "differential" psychologists have finally pushed beyond the social sciences and into the medical laboratory. PET scans and EEG's, which can now roughly estimate IQ's (and thus g's), show that high-g brains work more quickly, economically, and consistently, like well-greased engines. In fact, this analogy could be almost literally true, if Edward M. Miller's hypothesis pans out that one determinant of general mental ability is the thickness of the fatty myelin coating neurons. These physiological studies suggest methods to raise IQ's, such as breastfeeding, the source of the ideal fats for infants' brains. Eventually, this kind of research may lead to higher IQ's through genetic engineering.

Already, better nutrition, better health care, less in-breeding, and other blessings enjoyed by recent generations have helped raise average g's. (For many of the same reasons, average heights have risen comparably.) Sadly, the white-black gap in average IQ's, which has stubbornly hovered around 15 points throughout the last 80 years of extraordinary change, seems likely to linger for at least decades more. Thus, these are the worst of times for g-men to go public with their discoveries. The fulminations against The Bell Curve have given way to a quieter, more effective clampdown, which has left missing in action two recent books with the identical title The g Factor. In 1996 Chris Brand, an Edinburgh U. psychologist, saw his own publisher yank back the unsold copies of his new book after reporters asked him about the IQ gap. Edinburgh later fired Brand, despite his 27 years of tenure, for expressing "disgraceful" opinions.

Arthur Jensen of Berkeley, the dean of psychometricians with 400 scientific papers published in refereed journals, struggled merely to find a publisher for his version of The g Factor, this heroically comprehensive summing up of his life's work. Finally, the small mail order imprint Praeger released Jensen's magnum opus … to shameful neglect. Even today, the only sure source for this fascinating (if dauntingly rigorous) landmark in the science of human nature remains the publisher (203-226-3571). [Since then, it's become reliably available through]

Stephen Jay Gould's The Mismeasure of Man, a 1981 book that continues to shape the non-scientific intelligentsia's feelings about IQ, demonized g as the "rotten core" of Prof. Jensen's 1969 article documenting the white-black IQ gap. The g Factor's overwhelming vindication of g, drawing on 15 years of new research, might seem likely to end the debate. It won't, of course, for reasons good and bad. The book sheds light on crucial new issues beyond the narrow scope of g (such as racial differences in nerdishness). More depressingly, few will grasp either its strengths or its limitations due to fundamental confusions rampant among American intellectuals about how to think about humanity.

For example, nobody noticed that Gould's assertion that human equality is a factual (rather than a moral, legal, or spiritual) reality centered on denouncing g; yet, g is the only concept that could conceivably make sense of his claim. Ironically, the g-ocentrists are among the last students of human nature making important discoveries within the egalitarian world-view. The one technique capable of uncovering mental equality is Jensen's: minimize the number of data points by measuring only the single most important factor (g) across only a few vast groups. Thus, Jensen, the Great Satan to egalitarian fundamentalists, delivers in Chapter 13 the most important pro-equality finding in recent decades: Men and women really do possess the same average g. Their equal average IQ's scores aren't just an artifact of IQ tests being rigged to produce this result. Jensen's finding is hugely important in itself: it's the best explanation of the splendid performance of women in many white-collar jobs.

Still, this example also shows that g, like any successful reductionist theory, has its limits. Males and females, while similar on mean g (but not on the standard deviation of g: guys predominate among both eggheads and knuckleheads), differ on several specific cognitive talents. Men, Jensen reports in passing, tend to be better at visual-spatial skills (especially at mentally rotating 3-d objects) and at mathematical reasoning. Women are generally superior at short-term memory, perceptual speed, and verbal fluency. Since the male sex is stronger at logically manipulating objects, while the female sex prevails at social awareness, that explains why most nerds are male, while most "berms" (anti-nerds adept at interpersonal skills and fashion) are female. Beyond cognition, there are other profound sex dissimilarities in personality, motivation, and physiology. All this helps explain the sexes' different patterns in career choices.

Because Jensen's simple, single-factor model can detect intellectual equality between men and women, it can also detect intellectual inequality between whites and blacks, if that's what the facts are. Although most responses to Jensen's equality/inequality model haven't risen above name-calling, obfuscation, guilt-by-association, and professional cowardice, there is a logical, fruitful alternative: develop a complex, multi-factor "diversity" model that rather than concentrating upon one difference among a very few groups, focuses on the many differences visible among many groups. Emphasizing the trade-offs necessary for achieving different goals, it makes toting up an overall winner look a little pointless.

The diversity perspective has much to offer, but only when it's thoroughly understood that it's inherently less empirically egalitarian than Jensenism. The diversity model's current popularity, however, stems from the wishful thinking that it discredits racial differences, on the assumption that since Diversity and Equality are both Good Things, they must be synonyms rather than antonyms. One particularly fashionable defense of empirical equality is to combine the doctrine that there "are no such things as races" (just swarms of little ethnic groups) with Harvard professor Howard Gardner's speculations about seven "multiple intelligences." Ergo, all groups must be equal, QED.

Let's do the math: assume, say, 100 ethnic groups and seven "intelligences." That's 700 data points. No way, no how could they all be equal -- our universe doesn't work like that. The more complex your model, the less equality and the more diversity you'll perceive in the world.

These kind of wooly-headed delusions that infest contemporary social thought stem fundamentally from the taboo against learning about humanity the way we'd learn about anything else: by noticing similarities and differences, which are the raw materials, the warp and woof, of information. The faster and more accurately a computer modem can discriminate the squawks coming down the phone line into 0's and 1's, the more information it can receive. Conversely, the more patterns it can discover among the data it's transmitting, the more it can compress the bits into similar groups, and thus the more information it can send. Disdaining to notice human contrasts isn't Respectable Science; it's intentional ignorance.

Even the 100 ethnic groups / seven intelligences model contains some useful truths. First, in the study of human biodiversity, as in any other science, there is a constructive tension, ultimately amounting to a symbiosis, between encyclopedically tabulating all genetic differences and devising parsimonious theories to cluster people according to their genetic similarities. The encyclopedist's glass is half full of fascinating ethnic anomalies that don't fit broad-brush racial theories. For example, the average Jewish IQ seems to surpass the average overall white IQ by as much as 17 points. Simultaneously, the theorist can half-fill his glass with sweeping racial patterns. For instance, he can frugally sum up much of the biodiversity that's blatantly obvious in America with Rushton's Rule: On most physical, cognitive, and behavioral dimensions, the West African and Northeast Asian averages lie at opposite extremes, with the white average in the mediocre middle.

Those who deny the reality of the races rightly point out that nobody agrees exactly on their number, names, or constituents. This is a valid point, but the identical criticism could be made of the reality of "extended families" … precisely because races are extremely extended families. Races differ qualitatively from extended families only in being more coherent and longer lasting, due to greater in-breeding.

Second, are there are lots of mental abilities? Sure. I could rattle off many more than Gardner's seven that I, personally, lack. Like races, nobody can quite agree on precisely what they are. Do we need scores of different cerebral skills, or can we get by with Gardner's seven intelligences. Or is Jensen's g good enough? Since most of the literati still think in terms of Platonic essences, this multiplicity of approaches strikes many as a conceptual scandal, but it's a practical boon: you can pick the optimal trade-off between comprehensiveness and ease-of-use for your particular task.

Isn't there something unscientific about ignoring outlying data that doesn't fit the theory? Interestingly, Jensen and Gardner, despite being so often portrayed as mortal enemies (actually, they are mildly admiring of each other's work), are both reductionists. The highest scientific honors have always gone to the theorists like Newton or Darwin rather than the cataloguers like Tyco Brahe or Linnaeus, because there is simply too much raw data for us to handle. Without scientific hypotheses, rules-of-thumb, prejudices, and gut instincts, we'd be as immobilized as Funes, the Jorge Luis Borges character cursed with infinite powers of perceptual discrimination that cost him his ability to synthesize and abstract meaning out of his oppressively detailed memory-dump.

The narrower the field, the better that simple models like g forecast success. For example, if you look only at major team sports, African-Americans are on average genetically superior at "general athleticism." Thus, race proves useful in predicting success … until you contemplate a broader variety of sports. Then, the greater average muscularity that helps make men of West African descent the kings of football and basketball tends to cause them in, say, marathon-running, dogsled-racing, and English Channel-swimming to (respectively) overheat, freeze, and sink.

Ironically, while diversity models are now popular in the abstract, it's nearly a hanging offense in the current mainstream media climate to actually mention particular talents in which minorities are superior to whites. (Today, "celebrating diversity" is automatically assumed to mean "insisting upon uniformity.") Gardner, for instance, coyly refuses to discuss the obvious racial and sexual disparities implicit in his seven factor model.

In the most publicized recent attempt to honestly flesh out a diversity model, the Reverend Reggie White of the Green Bay Packers asked the Wisconsin legislature, "Why did God make us so different?" He then listed what he saw as the different strengths of America's races, and concluded, "When you put all of that together … it forms a complete image of God." Despite being black, a football hero, an outstanding citizen, obviously well-intended, and in at least some of his examples undeniably right (e.g., Asians are gifted at invention, "they can turn a TV into a watch"), the Rev. White was pilloried by the press: "Stereotypes!"

Of course, none of the tut-tutters asked: Is a diversity model needed to describe specific black mental advantages overlooked by g? As a Reggieist (i.e., one who considers human biodiversity both a reality and a net blessing), I'm pleased to point out that IQ tests can't accurately measure at least one mental faculty in which blacks tend to outperform whites and Asians in real life. Despite lower mean IQ's, African-Americans are not a race of talentless dullards, but are instead the most charismatic contributors to 20th Century popular culture. What mental factor underlies the black revolutions in music, sport, oratory, dance, and slang? Subjective, improvisatory creativity.

For example, like a lot of NBA stars, Scottie Pippen's below-market contract, ill-timed trade demands, team-damaging pouts, and numerous child-support obligations imply that when given time to think, he often chooses unwisely. Yet, in the flow of the game, he's a Talleyrand at real-time decision-making. Leading a fast break, there are no permanent right answers. Even "Pass the ball to Michael Jordan" gets old fast as defenses habituate. Similarly, the NFL running back, the jazz soloist, the preacher, and the rapping DJ all must heed others' expectations and instantly respond with something a little unexpected. IQ tests -- by necessity objective and standardized -- can never measure this adequately.

Further, despite his data's inevitable shortcomings in this regard, Jensen does report that blacks possess particular mental weaknesses and strengths. Among individuals with equal g's, whites and Asians (like males) are typically stronger in those visual-spatial skills so useful in engineering and many skilled trades. In contrast, blacks (like females) often enjoy better short-term memories and thus can mentally juggle more balls in social situations. (This probably contributes to the black advantage in improvisation). Jensen's findings confirm my intuition (NR, 4/6/98) that while whites and Asians tend to be less masculine than blacks in physique and personality, they are typically more masculine than blacks in mental abilities. Put bluntly, whites and Asians tend to be nerdier than blacks. How many blacks would sincerely disagree?

Thus, the IQ disparity is less apocalyptic than is generally assumed. In fact, it's not all that unique -- diversity is among the oldest and most pervasive problems / opportunities inherent in the human condition. Because everybody is less innately talented than somebody else at something, the human race has worked out some pragmatic ways to deal with this.

Since Adam Smith and David Ricardo, economic theory has recommended specializing in whatever's your greatest comparative advantage. The peculiar problem facing blacks, though, is their specific talents are most valuable in winner-take-all professions like entertainment and sports. Still, the masculine bermishness common among blacks should also be helpful in more broadly remunerative occupations like sales.

Even if blacks had no special skills, just a deficiency of g, methods used by white and Mexican athletes to deal with black superiority in team sports might offer blacks practical hints in partially mitigating the g-gap. Specialization, for instance, is still valuable. (As illustrated by their most famous star Fernando Valenzuela, Mexicans don't tend to be endowed with ideal, Ken Griffey Jr.-style bodies for baseball. Yet, through an intense focus on the game they've built a critical mass of baseball expertise.) Avoid affirmative action programs that prevent critical masses from emerging. Look for fields where the inherent demands are less (e.g., golf rather than football) or competition is lighter (e.g., volleyball instead of basketball).


Work harder than your more gifted rivals. Master the fundamentals. Nail the easy stuff. (E.g., the only category in which whites are over-represented among NBA leaders is free-throw shooting). Don't improvise: listen to your coach's wisdom. (E.g., the decline of traditional sexual morality has not lead to a high pregnancy rate among coldly logical Dutch teens. For African-American teens, though, the rise of do-it-yourself morality in the 1960's was a disaster.) Challenge yourself, but realistically. (E.g., I need to get in shape, but an affirmative action program for Sedentary-Americans that sets-aside for me an opening in Evander Holyfield next heavyweight title bout might not be in my best interest. The same goes for racial quotas at elite colleges.)

Finally, the U.S. Army offers the bracing example of an institution that has elicited a high level of black achievement, in part by demanding that those with high-IQ's search out what Richard Epstein calls simple rules for a complex world. In dismal contrast, research universities fail blacks because the publish-or-perish system encourages the high-IQ to wallow in abstruseness. Denouncing Jensen proclaims one's faith in empirical egalitarianism, which serves as the perfect excuse for ignoring the irksome demands of moral egalitarianism. By declaring that everyone could Be Like Me (if only they were properly socialized), the clever can, with clear conscience, continue to surreptitiously wage class war against the clueless.

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