by Morton Hunt
The Army Testing Program, however, had far greater impact outside the military than within it. It made America more conscious than ever of the practical applications of psychology, specifically those derived from mental measurement. (James McKeen Cattell said that the war had put psychology “on the map,” and G. Stanley Hall that it had given psychology an invaluable redirection toward the practical rather than the “pure.”)
The Alpha, in particular, led to an explosive expansion of intelligence testing, which rapidly became a multimillion-dollar industry. Within a few years of the war’s end, a number of Alpha-type paper-and-pencil intelligence tests were being marketed to school administrators throughout the country. One of the most successful, appearing in 1923, was put together by Terman, Yerkes, and three co-workers, under the auspices of the National Research Council, which advertised it as “the direct result of the application of the army testing methods to school needs.” By the end of the decade it had been given to seven million American school-children.52 Another major success was the Scholastic Aptitude Test, developed by Carl C. Brigham, a colleague of Yerkes’, from Army models. Testing became prevalent in schools, colleges, the military services, institutions of all sorts, and various segments of industry.
The widespread use of intelligence testing was given further impetus by statistical evidence that the tests measured not just a series of separate mental aptitudes but an innate core of mental ability or “general intelligence.” Charles Spearman, an English psychologist and statistician, had shown that many mental abilities are correlated. (A person who does well in vocabulary, for instance, is likely to do well in arithmetic and other subtests.) He took this to indicate that an inherent general intelligence, which he called g, underlay all the specific abilities. Even if intelligence tests relied in part on learning, the correlations implied the existence of an innate ability to learn.
This provided additional justification for intelligence testing in the schools, which by the 1930s, both in the United States and in Great Britain, were classifying pupils early in the educational process and assigning them to broad programs preparatory for higher education or to narrow “vocational” or “technical” programs readying them for blue-collar jobs. In America this was called “tracking” and in Great Britain “streaming.”53
The growth of testing was not limited to the measurement of intelligence. During the 1920s and 1930s many other scales were developed to measure musical, mechanical, figural, verbal, mathematical, and other abilities, and a number of vocational aptitudes. Even though intelligence testing itself came under attack as early as the 1920s, Binet’s approach to mental testing had opened up a vast new area of psychological research, and the Army Alpha had transformed his cumbersome and costly procedure into one that was easy and inexpensive enough to be the psychological equivalent of the assembly line.
The IQ Controversy
Intelligence testing did not long maintain its unquestioned status. From 1921 on, when Yerkes edited a massive report of the findings of the Army Testing Program, intelligence testing came under attack by various advocates and spokespersons of the underprivileged, who claimed that it measured not innate intelligence but acquired knowledge and cultural values and therefore was biased in favor of the dominant white middle class and against the lower classes and immigrants.
The Alpha, they charged, measured not native intelligence but the kinds of knowledge possessed by men with schooling and a degree of sophistication. Here, for instance, is a typical example of the culturally biased kind of question:
The Knight engine is used in the
—Packard,
—Stearns,
—Lozier,
—Pierce Arrow.
The Beta was similarly far from impartial: in it, illiterates had to complete certain pictures such as a face without a mouth—fair enough—but others, such as a lightbulb without a filament or a tennis court without a net, made many lower-class men and immigrants seem stupid.54
The same criticism was made, and rightly so, as far as the Stanford-Binet scale was concerned. Many or most of the items in it measure a combination of inherent ability and acquired information or skills, but a person who has had little chance to acquire the information or skills will do poorly with the questions, no matter what his or her inherent mental power.
At the twelve-year-old level, for instance, the Stanford-Binet asked for definitions of “charity” and “justice.” If a Mexican-American child from a rural southwestern shanty town gave inadequate answers, did that indicate a lack of innate intelligence or the child’s failure to learn the meanings of those concepts in white, middle-class America? Again, at the eight-year-old level Stanford-Binet asked, “What’s the thing for you to do when you have broken something which belongs to someone else?” If the eight-year-old lived in a city slum where children struggled to survive, was his or her answer a gauge of innate intelligence or of the mores and folkways of the slum subculture?
Binet had left moot the extent to which mental development, measured by his scale, was due to heredity and to experience. But the tenor of Terman’s comments in The Measurement of Intelligence (the Stanford-Binet instruction manual), despite the disclaimer quoted above, was that intelligence is largely hereditary and that poor scores reveal mental deficiency—which, he said, was a genetic and a racial trait:
[Low intelligence] is very, very common among Spanish-Indian and Mexican families of the Southwest and also among negroes. Their dullness seems to be racial, or at least inherent in the family stocks from which they come… The writer predicts that… there will be discovered enormously significant racial differences in general intelligence, differences which cannot be wiped out by any scheme of mental culture.55
In 1922, the respected columnist and pundit Walter Lippmann launched a critical attack in The New Republic on Terman, Yerkes, and others who claimed that intelligence testing measured innate mental ability. Lippmann sounded the theme, repeated from that time until now, that such testing stamped a permanent label of inferiority on children, especially the underprivileged, and served the purposes of the prejudiced and the powerful.56
He and others who shared his views had even stronger grounds for objecting to the Army Alpha and Beta than to the Stanford-Binet, and for disputing Yerkes’ claim that tests modeled on the Alpha “measure native intellectual ability.” The answers to many Alpha questions clearly required learned information rather that intelligence, as Stephen Jay Gould later made plain in his polemical study, The Mismeasure of Man, in which he cited these examples:57
Washington is to Adams as first is to…
Crisco is a: patent medicine, disinfectant, toothpaste, food product.
The number of a Kaffir’s legs is: 2, 4, 6, 8.
Christy Mathewson is famous as a: writer, artist, baseball player, comedian.
Beta, for illiterate subjects, in the choice of pictures to be completed was similarly unfair, as already mentioned.
The result was to give a distorted assessment of the population and the effects on it of immigration. The Army Testing Program, as presented by Yerkes in his 1921 report, portrayed a society whose population was being degraded by increases in poor genetic stock. According to the Alpha and Beta, the average mental age of white American males was only thirteen, just above the level of moronity, although Terman had previously put the figure at sixteen. Gould said that this shocking datum lent power to xenophobic, racist, and elitist elements in America:
The new figure became a rallying point for eugenicists who predicted doom and lamented our declining intelligence, caused by the unconstrained breeding of the poor and feeble-minded, the spread of Negro blood through miscegenation, and the swamping of an intelligent native stock by the immigrating dregs of southern and eastern Europe.58
Yerkes also lent support to Goddard’s Ellis Island data by reporting that the Alpha and Beta showed the peoples of southern Europe and the Slavs of eastern Europe to be less intelligent than the peoples of northern and w
estern Europe; these “findings” helped bring about the 1924 immigration law.
As the IQ controversy grew more heated, however, intelligence testing began to lose favor among psychologists during the 1930s and still more in the 1940s. By then, too, the belief in general intelligence had waned; new research using advanced statistical methods had found all sorts of “factors” or clusters of special correlations among the traits and cast doubts on the meaningfulness or usefulness of Spearman’s g. Still, tests measuring a number of mental abilities and yielding a composite score, called intelligence, continued to be used by educators, business heads, and others.
By the 1960s, however, with protest movements of the disenfranchised and the discriminated-against gaining power, a protracted IQ war got under way. According to a study the author of this book made in 1999:
Militant minority groups and their white sympathizers [in the civil rights movement] succeeded in getting the boards of education in several major cities to stop IQ testing in the public schools. Public demonstrations and mass protests by activist groups died down by the late 1970s, but efforts to stop IQ testing continued by means of court cases and pressures on state legislators.
And with considerable success. By the 1990s, in schools throughout California, and in many school systems in other states, laws had been passed that forbade giving standardized tests of intelligence and academic aptitude to minority black and Hispanic children who had scholastic problems. In other cases school administrators who were not legally forbidden to do such testing avoided it in response to the wishes of parents… Nationally, between a third and a half of all public school districts administered no group intelligence or aptitude tests K to 12, and of those that did, according to a survey of eastern states, about half made little or no use of the results to tailor programs to students’ abilities.59
Some psychologists went so far as to deny that there was such a thing as intelligence. Professor Martin Deutsch of New York University asserted, “It’s a convenient label for certain kinds of behavior, but I suspect that, in actual fact, the thing itself doesn’t really exist.” Other psychologists and educators preferred to state, as Boring had done earlier, that one cannot say what intelligence is but only that it is what intelligence tests measure.
To meet the criticisms of existing IQ tests, in 1958 the psychologist David Wechsler developed two new ones, the Wechsler Intelligence Scale for Children (known as WISC) and the Wechsler Adult Intelligence Scale (WAIS). WISC and WAIS have two major parts: a verbal subtest assesses vocabulary, comprehension, and other aspects of verbal ability, and a performance subtest is made up of nonverbal tasks such as arranging pictures in an order that tells a story, or spotting the missing elements in a picture. Over the years intelligence researchers have modified and improved them as well as the Stanford-Binet Intelligence Scale to better measure the abilities of test takers from diverse cultural and linguistic backgrounds, and have developed more sophisticated and fairer ways of administering and interpreting the tests.60
Accordingly, despite the long history of opposition to intelligence tests, WISC and WAIS have continued to be widely used in their latest versions (WISC III and WAIS III), and for good reason.
For one thing, in those school systems that use them they predict rather well how children will perform in school and which children should be given special attention or be enrolled in enrichment programs.
For another, a number of recent, statistically sophisticated studies of fraternal twins and identical twins, particularly pairs who were separated shortly after birth and reared in dissimilar homes, have established, far better than Galton could, that mental abilities are in considerable part due to genetic makeup, and therefore that intelligence testing does indeed test innate ability as well as acquired knowledge.61
This graph clearly shows the two influences of genetics and environment on IQ.
FIGURE 1
IQ and genetic relationship
Each bar shows how closely the IQ scores of the individuals listed are related. For instance, the top bar indicates that if identical twins are reared together—genetics and environment being the same—their IQs will have a greater than 0.8 correlation (or in informal terms, are very likely to be the same or nearly so.) In contrast, the bar for siblings reared apart—with only half the same genes and different environments— shows that their IQs are likely to be rather different.
(Data of this kind are often mislabeled “heritability,” which is a quite different matter. Heritability refers to how much of the range of differences in a given trait, within a group of people, results from genetics. If the heritability of intelligence were found to be zero, no part of the range from nearly zero to 200 would be of genetic origin; if it were 100 percent, all of the variance would be of genetic origin. Recent reviews of a variety of studies of heritability of IQ conclude that roughly half of the variance in IQ scores is due to genetic makeup.62 But how genetic makeup interacts with culture and which contributes how much of the result in any individual is a complex issue, only now being studied in new and illuminating ways—an area of contemporary psychology that we will see more of later in this history.)
One reason test designers have had to keep tinkering with the IQ tests is bizarre: in Western society, IQ scores have risen about three points every decade. The average IQ today would be 115 if the tests were scored as they were 50 years ago. To correct for this, scoring methods are periodically adjusted to keep the mean at 100.63 Several explanations of the improving average scores have been offered: one, that daily life has become more challenging and thereby increased people’s coping ability; two, that nutrition is better and has increased height—and, possibly, brain functioning; and three, that perhaps there has been no real increase in IQ but only in the kind of reasoning ability that is useful in test taking. At present, the definite explanation for rising IQ scores is not known.64
A more serious challenge to the status of IQ tests is the development of more complex portrayals of intelligence. Rather than the summary entity g, a number of theories have been offered in recent years that distinguish among kinds of intelligence. The two that currently command the most attention are those of Robert Sternberg of Yale and Howard Gardner of Harvard. Sternberg distinguishes between analytical intelligence (such as one uses in solving anagrams), creative intelligence (called upon in problem solving), and practical intelligence (used in the management of everyday affairs).65 Gardner’s view is more complex: He identifies (and offers evidence for) eight intelligences, some of which are promoted by Western society, others by other societies.66 Here—and we will spare ourselves the details—are his eight:
—Logical-mathematical
—Linguistic
—Naturalist
—Musical
—Spatial
—Bodily kinesthetic
—Interpersonal
—Intrapersonal
His evidence is persuasive—and indeed nearly everyone has known people who are particularly gifted in one or more of these areas but all too average, or even deficient, in some of the others.
Yet despite these and other challenges and oppositions to standard IQ testing, it continues to be “one of psychology’s greatest successes,” writes Etienne Benson, a staff member of Monitor on Psychology, an online publication of the American Psychological Association. “It is certainly one of the field’s most persistent and widely used inventions.”67 Many of the biases identified by critics of intelligence testing have been reduced, she says, and since the 1970s the field has acquired more sophisticated methods of interpretation, more advanced statistics, and new, methodologically more sophisticated, tests.68
In addition to all the uses made of IQ testing, it also is an essential tool for various kind of neurological research. Psychologists have long wondered whether the brains of highly intelligent people differ, physically, from those of average people. A new study initiated by the National Institute of Mental Health, relying on brain scans by magnetic resonance im
aging over a period of seventeen years, has shown that the cortex— the outer sheet of neurons covering the brain that is the seat of many higher mental processes—grows thicker than average in highly intelligent children as they age and then thins out later, ending up even thinner than average. “This is the first time that anyone has shown that the brain grows differently in extremely intelligent children,” says Paul M. Thompson, a brain-imaging expert at the University of California at Los Angeles. Apparently, the brains of the highly intelligent children are rewiring themselves, developing fruitful connections among the neurons and later pruning out redundant ones, thus operating more effectively during childhood and remaining more effective in adulthood. And here’s the point: All the data on the different growth of these children’s brains would tell us nothing about intelligence were it not for the IQ tests and scores taken along with the scans.69
The IQ controversy has raged, died down, and raged again; politics beclouds science, and science is used for political ends. The struggle continues and shows no signs of ending, but lineal descendants of the early intelligence tests, now greatly modified and more nearly “culture-fair” than the early tests, are widely used in schools, institutions, the military, industry, and elsewhere.