He also came across a tramp and a woman, both of whom repelled him by their half-witted insensibility and seeming cruelty, but even in them he failed to see the criminal type as described in the Italian school of criminology: he saw in them only people who were repulsive to him personally, like others were whom he met outside prison walls—in swallowtail coats, wearing epaulets or bedecked with lace.…
At first he had hoped to find the answer in books, and bought everything he could find on the subject. He bought the works of Lombroso and Garofalo [an Italian baron and disciple of Lombroso], Ferri, Liszt, Maudsley and Tarde, and read them carefully. But as he read, he became more and more disappointed.… Science answered thousands of very subtle and ingenious questions touching criminal law, but certainly not the one he was trying to solve. He was asking a very simple thing: Why and by what right does one class of people lock up, torture, exile, flog, and kill other people, when they themselves are no better than those whom they torture, flog and kill? And for answers he got arguments as to whether human beings were possessed of free will or not. Could criminal propensities be detected by measuring the skull, and so on? What part does heredity play in crime? Is there such a thing as congenital depravity? (Resurrection, 1899, 1966 edition translated by R. Edmonds, pp. 402–403.)
Epilogue
We live in a more subtle century, but the basic arguments never seem to change. The crudities of the cranial index have given way to the complexity of intelligence testing. The signs of innate criminality are no longer sought in stigmata of gross anatomy, but in twentieth-century criteria: genes and fine structure of the brain.
In the mid-1960s, papers began to appear linking a chromosomal anomaly in males known as XYY with violent and criminal behavior. (Normal males receive a single X chromosome from their mothers and a Y from their fathers; normal females receive a single X from each of their parents. Occasionally, a child will receive two Y’s from his father. XYY males look like normal males, but tend to be a little above average in height, have poor skin and may tend, on average—though this is disputed—to be somewhat deficient in performance on intelligence tests.) Based on limited observation and anecdotal accounts of a few XYY individuals, and on a high frequency of XYY’s in mental-penal institutions for the criminally insane, a tale about criminal chromosomes originated. The story exploded into public consciousness when attorneys for Richard Speck, murderer of eight student nurses in Chicago, sought to mitigate his punishment with a claim that he was XYY. (In fact, he is a normal XY male.) Newsweek published an article entitled “Congenital criminals,” and the press churned out innumerable reports about this latest reincarnation of Lombroso and his stigmata. Meanwhile, scholarly study picked up, and hundreds of papers have now been written on the behavioral consequences of being XYY. A well-intentioned but, in my opinion, naïve group of Boston doctors began an extensive screening program upon newborn boys. They hoped that by monitoring the development of a large sample of XYY boys, they might establish whether any link existed with aggressive behavior. But what of the self-fulfilling prophesy? for parents were told, and no amount of scholarly tentativeness can overcome both press reports and inferences made by worried parents from the aggressive behavior manifested from time to time by all children. And what of the anguish suffered by parents, especially if the connection be a false one—as it almost surely is.
In theory, the link between XYY and aggressive criminality never had much going for it beyond the singularly simplistic notion that since males are more aggressive than females and possess a Y that females lack, Y must be the seat of aggression and a double dose spells double-trouble. One group of researchers proclaimed in 1973 (Jarvik et al., pp. 679–680): “The Y chromosome is the male-determining chromosome; therefore, it should come as no surprise that an extra Y chromosome can produce an individual with heightened masculinity, evinced by characteristics such as unusual tallness, increased fertility … and powerful aggressive tendencies.”
The tale of XYY as a criminal stigma has now been widely exposed as a myth (Borgaonkar and Shah, 1974; Pyeritz et al., 1977). Both these studies expose the elementary flaws of method in most literature claiming a link between XYY and criminality. XYY males do seem to be represented disproportionately in mental-penal institutions, but there is no good evidence for high frequencies in ordinary jails. A maximum of 1 percent of XYY males in America may spend part of their lives in mental-penal institutions (Pyeritz et al., 1977, p. 92). Adding to this the number that may be incarcerated in ordinary jails at the same frequency as normal XY males, Chorover (1979) estimates that 96 percent of XYY males will lead ordinary lives and never come to the attention of penal authorities. Quite a criminal chromosome! Moreover, we have no evidence that the relatively high proportion of XYY’s in mental-penal institutions has anything to do with high levels of innate aggressivity.
Other scientists have looked to malfunction in specific areas of the brain as a cause of criminal behavior. After extensive ghetto riots during the summer of 1967, three doctors wrote a letter to the prestigious Journal of the American Medical Association (cited in Chorover, 1979):
It is important to realize that only a small number of the millions of slum dwellers have taken part in the riots, and that only a subfraction of these rioters have indulged in arson, sniping and assault. Yet, if slum conditions alone determined and initiated riots, why are the vast majority of slum dwellers able to resist the temptations of unrestrained violence? Is there something peculiar about the violent slum dweller that differentiates him from his peaceful neighbors?
We all tend to generalize from our own areas of expertise. These doctors are psychosurgeons. But why should the violent behavior of some desperate and discouraged people point to a specific disorder of their brain while the corruption and violence of some congressmen and presidents provokes no similar theory? Human populations are highly variable for all behaviors; the simple fact that some do and some don’t provides no evidence for a specific pathology mapped upon the brain of doers. Shall we concentrate upon an unfounded speculation for the violence of some—one that follows the determinist philosophy of blaming the victim—or shall we try to eliminate the oppression that builds ghettos and saps the spirit of their unemployed in the first place?
FIVE
The Hereditarian Theory of IQ
An American Invention
Alfred Binet and the original purposes of the Binet scale
Binet flirts with craniometry
When Alfred Binet (1857–1911), director of the psychology laboratory at the Sorbonne, first decided to study the measurement of intelligence, he turned naturally to the favored method of a waning century and to the work of his great countryman Paul Broca. He set out, in short, to measure skulls, never doubting at first the basic conclusion of Broca’s school:
The relationship between the intelligence of subjects and the volume of their head … is very real and has been confirmed by all methodical investigators, without exception.… As these works include observations on several hundred subjects, we conclude that the preceding proposition [of correlation between head size and intelligence] must be considered as incontestable (Binet, 1898, pp. 294–295).
During the next three years, Binet published nine papers on craniometry in L’Année psychologique, the journal he had founded in 1895. By the end of this effort, he was no longer so sure. Five studies on the heads of school children had destroyed his original faith.
Binet went to various schools, making Broca’s recommended measurements on the heads of pupils designated by teachers as their smartest and stupidest. In several studies, he increased his sample from 62 to 230 subjects. “I began,” he wrote, “with the idea, impressed upon me by the studies of so many other scientists, that intellectual superiority is tied to superiority of cerebral volume” (1900, p. 427).
Binet found his differences, but they were much too small to matter and might only record the greater average height of better pupils (1.401 vs. 1.378 meters). Most measures
did favor the better students, but the average difference between good and poor amounted to a mere millimeter—“extrêmement petite” as Binet wrote. Binet did not observe larger differences in the anterior region of the skull, where the seat of higher intelligence supposedly lay, and where Broca had always found greatest disparity between superior and less fortunate people. To make matters worse, some measures usually judged crucial in the assessment of mental worth favored the poorer pupils—for anteroposterior diameter of the skull, poorer students exceeded their smarter colleagues by 3.0 mm. Even if most results tended to run in the “right” direction, the method was surely useless for assessing individuals. The differences were too small, and Binet also found that poor students varied more than their smarter counterparts. Thus, although the smallest value usually belonged to a poor pupil, the highest often did as well.
Binet also fueled his own doubts with an extraordinary study of his own suggestibility, an experiment in the primary theme of this book—the tenacity of unconscious bias and the surprising malleability of “objective,” quantitative data in the interest of a preconceived idea. “I feared,” Binet wrote (1900, p. 323), “that in making measurements on heads with the intention of finding a difference in volume between an intelligent and a less intelligent head, I would be led to increase, unconsciously and in good faith, the cephalic volume of intelligent heads and to decrease that of unintelligent heads.” He recognized the greater danger lurking when biases are submerged and a scientist believes in his own objectivity (1900, p. 324): “Suggestibility … works less on an act of which we have full consciousness, than on a half-conscious act—and this is precisely its danger.”
How much better off we would be if all scientists submitted themselves to self-scrutiny in so forthright a fashion: “I want to state very explicitly,” Binet wrote (1900, p. 324), “what I have observed about myself. The details that follow are those that the majority of authors do not publish; one does not want to let them be known.” Both Binet and his student Simon had measured the same heads of “idiots and imbeciles” at a hospital where Simon was in intern. Binet noted that, for one crucial measurement, Simon’s values were consistently less than his. Binet therefore returned to measure the subjects a second time. The first time, Binet admits, “I took my measures mechanically, without any other preconception than to remain faithful to my methods.” But the second time “I had a different preconception.… I was bothered by the difference” between Simon and myself. “I wanted to reduce it to its true value.… This is self-suggestion. Now, capital fact, the measures taken during the second experiment, under the expectation of a diminution, are indeed smaller than the measures taken [on the same heads] during the first experiment.” In fact, all but one head had “shrunk” between the two experiments and the average diminution was 3 mm—a good deal more than the average difference between skulls of bright and poor students in his previous work.
Binet spoke graphically of his discouragement:
I was persuaded that I had attacked an intractable problem. The measures had required travelling, and tiring procedures of all sorts; and they ended with the discouraging conclusion that there was often not a millimeter of difference between the cephalic measures of intelligent and less intelligent students. The idea of measuring intelligence by measuring heads seemed ridiculous.… I was on the point of abandoning this work, and I didn’t want to publish a single line of it (1900, p. 403).
At the end, Binet snatched a weak and dubious victory from the jaws of defeat. He looked at his entire sample again, separated out the five top and bottom pupils from each group, and eliminated all those in the middle. The differences between extremes were greater and more consistent—3 to 4 mm on average. But even this difference did not exceed the average potential bias due to suggestibility. Craniometry, the jewel of nineteenth-century objectivity, was not destined for continued celebration.
Binet’s scale and the birth of IQ
When Binet returned to the measurement of intelligence in 1904, he remembered his previous frustration and switched to other techniques. He abandoned what he called the “medical” approaches of craniometry and the search for Lombroso’s anatomical stigmata, and decided instead on “psychological” methods. The literature on mental testing, at the time, was relatively small and decidedly inconclusive. Galton, without notable success, had experimented with a series of measurements, mostly records of physiology and reaction time, rather than tests of reasoning. Binet decided to construct a set of tasks that might assess various aspects of reasoning more directly.
In 1904 Binet was commissioned by the minister of public education to perform a study for a specific, practical purpose: to develop techniques for identifying those children whose lack of success in normal classrooms suggested the need for some form of special education. Binet chose a purely pragmatic course. He decided to bring together a large series of short tasks, related to everyday problems of life (counting coins, or assessing which face is “prettier,” for example), but supposedly involving such basic processes of reasoning as “direction (ordering), comprehension, invention and censure (correction)” (Binet, 1909). Learned skills like reading would not be treated explicitly. The tests were administered individually by trained examiners who led subjects through the series of tasks, graded in their order of difficulty. Unlike previous tests designed to measure specific and independent “faculties” of mind, Binet’s scale was a hodgepodge of diverse activities. He hoped that by mixing together enough tests of different abilities he would be able to abstract a child’s general potential with a single score. Binet emphasized the empirical nature of his work with a famous dictum (1911, p. 329): “One might almost say, ‘It matters very little what the tests are so long as they are numerous.”
Binet published three versions of the scale before his death in 1911. The original 1905 edition simply arranged the tasks in an ascending order of difficulty. The 1908 version established the criterion used in measuring the so-called IQ ever since. Binet decided to assign an age level to each task, defined as the youngest age at which a child of normal intelligence should be able to complete the task successfully. A child began the Binet test with tasks for the youngest age and proceeded in sequence until he could no longer complete the tasks. The age associated with the last tasks he could perform became his “mental age,” and his general intellectual level was calculated by subtracting this mental age from his true chronological age. Children whose mental ages were sufficiently behind their chronological ages could then be identified for special educational programs, thus fulfilling Binet’s charge from the ministry. In 1912 the German psychologist W. Stern argued that mental age should be divided by chronological age, not subtracted from it,* and the intelligence quotient, or IQ, was born.
IQ testing has had momentous consequences in our century. In this light, we should investigate Binet’s motives, if only to appreciate how the tragedies of misuse might have been avoided if its founder had lived and his concerns been heeded.
In contrast with Binet’s general intellectual approach, the most curious aspect of his scale is its practical, empirical focus. Many scientists work this way by deep conviction or explicit inclination. They believe that theoretical speculation is vain and that true science progresses by induction from simple experiments pursued to gather basic facts, not to test elaborate theories. But Binet was primarily a theoretician. He asked big questions and participated with enthusiasm in the major philosophical debates of his profession. He had a long-standing interest in theories of intelligence. He published his first book on the “Psychology of Reasoning” in 1886, and followed in 1903 with his famous “Experimental Study of Intelligence,” in which he abjured previous commitments and developed a new structure for analyzing human thinking. Yet Binet explicitly declined to award any theoretical interpretation to his scale of intelligence, the most extensive and important work he had done in his favorite subject. Why should a great theoretician have acted in such a curious and apparently contradic
tory way?
Binet did seek “to separate natural intelligence and instruction” (1905, p. 42) in his scale: “It is the intelligence alone that we seek to measure, by disregarding in so far as possible, the degree of instruction which the child possesses.… We give him nothing to read, nothing to write, and submit him to no test in which he might succeed by means of rote learning” (1905, p. 42). “It is a specially interesting feature of these tests that they permit us, when necessary, to free a beautiful native intelligence from the trammels of the school” (1908, p. 259).
Yet, beyond this obvious desire to remove the superficial effects of clearly acquired knowledge, Binet declined to define and speculate upon the meaning of the score he assigned to each child. Intelligence, Binet proclaimed, is too complex to capture with a single number. This number, later called IQ, is only a rough, empirical guide constructed for a limited, practical purpose:
The scale, properly speaking, does not permit the measure of the intelligence, because intellectual qualities are not superposable, and therefore cannot be measured as linear surfaces are measured (1905, p. 40).
Moreover, the number is only an average of many performances, not an entity unto itself. Intelligence, Binet reminds us, is not a single, scalable thing like height. “We feel it necessary to insist on this fact,” Binet (1911) cautions, “because later, for the sake of simplicity of statement, we will speak of a child of 8 years having the intelligence of a child of 7 or 9 years; these expressions, if accepted arbitrarily, may give place to illusions.” Binet was too good a theoretician to fall into the logical error that John Stuart Mill had identified—“to believe that whatever received a name must be an entity or being, having an independent existence of its own.”
The Mismeasure of Man Page 18