Book Review : Author Votes for Nature Over Nurture

Why Humans Vary in Intelligence by Seymour W. Itzkoff (Paideia Publishers, P.O. Box 343, Ashfield, Mass. 01330, $18, 382 pages)

Today we take up a book that asserts flatly and unflinchingly that intelligence is hereditary and that significant differences in native intelligence exist and can be measured between the sexes and between the races. It further says that these biological differences in intelligence are completely explainable by mankind’s evolutionary history.

The author, Seymour W. Itzkoff of Smith College, argues that the perennial question of nature vs. nurture “has been resolved . . . on the side of nature,” and he supplies much evidence in support of that view.

What’s more, he says, social niceties and political necessities make it impossible for society to face these facts. Instead, reformers invent “an endless progression of ‘bourgeois,’ ‘racist,’ ‘sexist’ demons that ostensibly stand in the way of their ever-receding Utopia.”

Itzkoff knows that readers will be tempted to dismiss his book as sexist and racist nonsense, an echo of obnoxious master-race theories of earlier times. We are rightly uncomfortable with assertions of one groups’ inherent superiority over another. But he repeatedly urges readers to be patient and insists that he is exploring the truth where it leads him regardless of its clash with conventional political wisdom.

Challenging Ideas

He begs forebearance for his views, and the result is a fascinating book that challenges accepted ideas. In the end, he hasn’t proved the case that the nature-nurture argument is settled, but he’s taken a good shot at it. In the process, “Why Humans Vary in Intelligence” says as much about intelligence as it does about human variation in intelligence, and it discusses intelligence provocatively and well.

As with the nature-nurture argument, Itzkoff declares certain basic arguments about intelligence to have been settled when in fact they have not been. Scholars continue to debate what, if anything, IQ tests measure and whether intelligence is one trait or many. Not Itzkoff. “IQ is in some measure predictive of intellectual achievement in school and in life,” he said, “and IQ variance between one person and another is about 70% heredity and 30% environment.”

Nor does he have any doubt that there is a male intelligence and a female intelligence and that the reason that men do much better than women in activities like mathematics and chess is that men have a “spatial/visual gene” that women do not. He dismisses the explanation that women from birth are socialized away from these activities, and he recounts experimental evidence to support his claim that there is a basic biological trait at work, independent of what girls are taught.

“What we see in the male superiority in math and chess is the most explicit and public intellectual manifestation of what tests and even social/historical experience have revealed about knowledge,” he said.

Big Brain Advantage

According to Itzkoff, a large brain and concomitant high intelligence gave humans an evolutionary advantage over mammals and other animals whose behavior was more rigidly controlled by instinct.

“For the infant,” he said, “the die was cast that a large brain accompanied increasingly helplessness. . . . Thus evolved the specialization of the female to secure the hearth and nurture her young.”

“Male ferocity,” on the other hand, “and aggression linked with raw intelligence, with no instinctive censors, created conditions for war and genocide many millions of years ago.”

The key event in the eventual success of Homo sapiens, he says, was the development of a large brain which, in addition to bestowing intelligence, also made men aggressive and predatory with an instinct to subjugate and control.

The fact that women do well in tasks that require fine small motor visual and manipulating skills, such as sewing, typing and putting together tiny computer elements shows, Itzkoff said “that women are more placid, patient and careful, whereas males, often more impatient and irritable, can be corralled less easily into this kind of careful, precise, mostly monotonous labor.”

Here again it seems, Itzkoff assumes the conclusion, which he then claims to have proved. Women taking sewing and typing can be explained as easily by culture as by heredity.

The same criticism applies to Itzkoff’s discussion of race. He asserts that whites as a group outperform blacks as a group in every intellectual task, but he gives short shrift to the response that this is the result of centuries of enslavement and discrimination.

Hereditary Factors

When he does respond to that argument, he says that Asian countries have propelled themselves into 20th-Century prosperity while African countries remain mired in poverty. But is this not also explainable by historical and cultural as well as by hereditary factors?

Itzkoff said his conclusions represent the consensus of knowledgeable researchers, that the debate is over and that these findings “have punctured the hopes of those who dreamed that an egalitarian world of uniformly intelligent and cultured persons could be created by waving a magic wand of philanthropic social, economic and educational policies.”

Not so fast. The other side isn’t willing to give up yet.