The Mismeasure of Man

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by Stephen Jay Gould


  The history of mental testing in the twentieth century has two major strands: scaling and ranking by mental age as represented by IQ testing, and analysis of correlations among mental tests as manifested in factor analysis. Effectively every popular work on mental testing explains the IQ thread in detail and virtually ignores factor analysis. This strategy is followed for an obvious and understandable reason: the IQ story is easy to explain and comprehend; factor analysis, and multivariate thinking in general, are enormously difficult for most people and hard to express without considerable mathematics.

  But such conventional works cannot adequately present the history of the hereditarian theory of unitary intelligence—for this notion relies so crucially on both parts. We must understand why people ever thought that a unilinear ranking could order people by mental worth—the IQ thread, usually well treated. But we cannot grasp or interpret the theory of unitary intelligence until we know the basis for the prior claim that intelligence can be interpreted as a single entity (that might then be measured by a single number like IQ). This rationale derives from factor analysis and its supposed validation of Spearman’s g—the unitary thing in the head. But factor analysis has usually been ignored, thus precluding all possibility of real understanding.

  I resolved that I would treat factor analysis head-on—and I have never struggled so hard to render material in a manner accessible to general readers. I kept failing because I could not translate the mathematics into understandable prose. Then I finally realized, in one of those “aha” insights, that I could use Thurstone’s alternative geometrical representation of tests and axes as vectors (arrows) radiating from a common point, rather than the usual algebraic formulations. This approach solved my problem because most people grasp pictures better than numbers. The resulting Chapter 7 is by no means easy. It will never rank high in public acclaim, but I have never been so proud of anything else I ever wrote for popular audiences. I think I found the key for presenting factor analysis, and one of the most important scientific issues of the twentieth century cannot be understood without treating this subject. Nothing has ever gratified me more than numerous unsolicited comments from professional statisticians over the years, thanking me for this chapter and affirming that I had indeed succeeded in conveying factor analysis, and that I had done so accurately and understandably. I am not nearly ready, but I will eventually chant my Nunc dimittis in peace.

  One final and peripheral point about factor analysis and Cyril Burt: My chapter on factor analysis bears the title “The Real Error of Cyril Burt: Factor Analysis and the Reification of Intelligence.” Burt had been charged with overt fraud in making up data for his studies, done at the end of a long career, on identical twins separated early in life and reared in different social circumstances. Inevitably, I suppose, some recent commentators have tried to rehabilitate Burt and to cast doubt upon the charges. I regard these attempts as weak and doomed to failure, for the evidence of Burt’s fraud seems conclusive and overwhelming to me. But I wish to emphasize that I regard the subject as unfortunate, diversionary, and unimportant—and the title of my chapter tried to express this view, though perhaps in a pun too opaque. Whatever Burt did or did not do as a pitiful old man (and I ended up feeling quite sympathetic toward him, not gloating over his exposure, but understanding the sources of his action in personal pain and possible mental illness), this late work had no enduring significance in the history of mental testing. Burt’s earlier, deep, and honest error embodies the fascinating and portentous influence of his career. For Burt was the most important of post-Spearmanian factor analysts (he inherited Spearman’s academic post)—and the key error of factor analysis lies in reification, or the conversion of abstractions into putative real entities. Factor analysis in the hereditarian mode, not later studies of twins, represented Burt’s “real” error—for reification comes from the Latin for res, or real thing.

  Inevitably, as for all active subjects, much has changed, sometimes to my benefit and sometimes to my deficit, since the book first appeared in 1981. But I have chosen to leave the main text essentially “as is” because the basic form of the argument for unitary, rankable, heritable, and largely unchangeable intelligence has never varied much, and the critiques are similarly stable and devastating. As noted before, I have deleted a few references topical to 1981, changed a few minor errors of typography and fact, and inserted a few footnotes to create a bit of dialogue between me in 1981 and me now. Otherwise, you read my original book in this revised edition.

  The major novelty of this revision lies in the two slices of bread that surround the meat of my original text—this prefatory statement in front and the concluding section of essays at the end. I have included five essays in two groups for this closing slice. The first group of two reproduces my two very different reviews of The Bell Curve. The first appeared in The New Yorker for November 28, 1994. I was particularly pleased because Mr. Murray became so apoplectic about this article, and because so many people felt that I had provided a comprehensive and fair (if sharp) commentary by critiquing both the illogic of The Bell Curve’s quadripartite general argument, and the inadequacies of the book’s empirical claims (largely exposed by showing how the authors buried conclusively contrary data in an appendix while celebrating their potential support in the main text). I felt grateful that this review was the first major comment to appear based on a complete reading and critique of the book’s actual text (others had written cogent commentaries on The Bell Curve’s politics, but had disclaimed on the text, pleading inability to comprehend the mathematics!). The second represents my attempts to provide a more philosophical context for The Bell Curve’s fallacy by considering its consonance with other arguments from the history of biodeterminism. This essay, published in Natural History in February 1995, repeats some material from The Mismeasure of Man in the section on Binet and the origin of the IQ test—but I left the redundancy alone since I thought that this different context for citing Binet might strike readers as interesting. The first section on Gobineau, the granddaddy of modern scientific racism, represents material that I probably should have originally placed, but did not, in The Mismeasure of Man.

  The second group includes three historical essays on key figures from the seventeenth, eighteenth, and nineteenth centuries respectively. We first meet Sir Thomas Browne and his seventeenth-century refutation of the canard “that Jews stink.” But I valued Browne’s argument primarily for following the cogent form that has opposed biodeterminism ever since—so his old refutation has enduring worth. This essay ends with a summary of the startling revision that modern genetic and evolutionary data about human origins must impose upon our notion of races and their meaning.

  The second essay analyzes the founding document of modern racial classification, the fivefold system devised in the late eighteenth century by the genially liberal German anthropologist Blumenbach. I use this essay to show how theory and unconscious presupposition always influence our analysis and organization of presumably objective data. Blumenbach meant well, but ended up affirming racial hierarchy by way of geometry and aesthetics, not by any overt viciousness. If you ever wondered why white folks are named Caucasians in honor of a small region in Russia, you will find the answer in this essay and in Blumenbach’s definitions. The last article summarizes Darwin’s sometimes conventional, sometimes courageous views on racial differences and ends with a plea for understanding historical figures in the context of their own times, and not in anachronistic reference to ours.

  I did not want to end with stale bread, and therefore sought to build this closing section from essays not previously anthologized. Of the five, only one has appeared before in my own collections—the last piece on Darwin from Eight Little Piggies. But I could not bear to expunge my personal hero, while concluding with this essay grants me symmetry by allowing the book to close with the same wonderful line from Darwin that both begins this essay on the opening slice of bread and serves as the epigraphic quote for the meat of
this book, the text of The Mismeasure of Man. One other essay—The New Yorker review of The Bell Curve—has been reprinted, in collections quickly published in response to Murray and Herrnstein’s book. The other essays have never been anthologized before, and I purposely left them out of my next collection to appear, Dinosaur in a Haystack.

  This subject of biodeterminism has a long, complex, and contentious history. We can easily get lost in the minutiae of abstract academic arguments. But we must never forget the human meaning of lives diminished by these false arguments—and we must, primarily for this reason, never flag in our resolve to expose the fallacies of science misused for alien social purposes. So let me close with the operative paragraph of The Mismeasure of Man: “We pass through this world but once. Few tragedies can be more extensive than the stunting of life, few injustices deeper than the denial of an opportunity to strive or even to hope, by a limit imposed from without, but falsely identified as lying within.”

  ONE

  Introduction

  CITIZENS OF THE REPUBLIC, Socrates advised, should be educated and assigned by merit to three classes: rulers, auxiliaries, and craftsmen. A stable society demands that these ranks be honored and that citizens accept the status conferred upon them. But how can this acquiescence be secured? Socrates, unable to devise a logical argument, fabricates a myth. With some embarrassment, he tells Glaucon:

  I will speak, although I really know not how to look you in the face, or in what words to utter the audacious fiction.… They [the citizens] are to be told that their youth was a dream, and the education and training which they received from us, an appearance only; in reality during all that time they were being formed and fed in the womb of the earth.…

  Glaucon, overwhelmed, exclaims: “You had good reason to be ashamed of the lie which you were going to tell.” “True,” replied Socrates, “but there is more coming; I have only told you half.”

  Citizens, we shall say to them in our tale, you are brothers, yet God has framed you differently. Some of you have the power of command, and in the composition of these he has mingled gold, wherefore also they have the greatest honor; others he has made of silver, to be auxiliaries; others again who are to be husbandmen and craftsmen he has composed of brass and iron; and the species will generally be preserved in the children.… An oracle says that when a man of brass or iron guards the State, it will be destroyed. Such is the tale; is there any possibility of making our citizens believe in it?

  Glaucon replies: “Not in the present generation; there is no way of accomplishing this; but their sons may be made to believe in the tale, and their son’s sons, and posterity after them.”

  Glaucon had uttered a prophesy. The same tale, in different versions, has been promulgated and believed ever since. The justification for ranking groups by inborn worth has varied with the tides of Western history. Plato relied upon dialectic, the Church upon dogma. For the past two centuries, scientific claims have become the primary agent for validating Plato’s myth.

  This book is about the scientific version of Plato’s tale. The general argument may be called biological determinism. It holds that shared behavioral norms, and the social and economic differences between human groups—primarily races, classes, and sexes—arise from inherited, inborn distinctions and that society, in this sense, is an accurate reflection of biology. This book discusses, in historical perspective, a principal theme within biological determinism: the claim that worth can be assigned to individuals and groups by measuring intelligence as a single quantity. Two major sources of data have supported this theme: craniometry (or measurement of the skull) and certain styles of psychological testing.

  Metals have ceded to genes (though we retain an etymological vestige of Plato’s tale in speaking of people’s worthiness as their “mettle”). But the basic argument has not changed: that social and economic roles accurately reflect the innate construction of people. One aspect of the intellectual strategy has altered, however. Socrates knew that he was telling a lie.

  Determinists have often invoked the traditional prestige of science as objective knowledge, free from social and political taint. They portray themselves as purveyors of harsh truth and their opponents as sentimentalists, ideologues, and wishful thinkers. Louis Agassiz (1850, p. 111), defending his assignment of blacks to a separate species, wrote: “Naturalists have a right to consider the questions growing out of men’s physical relations as merely scientific questions, and to investigate them without reference to either politics or religion.” Carl C. Brigham (1923), arguing for the exclusion of southern and eastern European immigrants who had scored poorly on supposed tests of innate intelligence stated: “The steps that should be taken to preserve or increase our present intellectual capacity must of course be dictated by science and not by political expediency.” And Cyril Burt, invoking faked data compiled by the nonexistent Ms. Conway, complained that doubts about the genetic foundation of IQ “appear to be based rather on the social ideals or the subjective preferences of the critics than on any first-hand examination of the evidence supporting the opposite view” (in Conway, 1959, p. 15).

  Since biological determinism possesses such evident utility for groups in power, one might be excused for suspecting that it also arises in a political context, despite the denials quoted above. After all, if the status quo is an extension of nature, then any major change, if possible at all, must inflict an enormous cost—psychological for individuals, or economic for society—in forcing people into unnatural arrangements. In his epochal book, An American Dilemma (1944), Swedish sociologist Gunnar Myrdal discussed the thrust of biological and medical arguments about human nature: “They have been associated in America, as in the rest of the world, with conservative and even reactionary ideologies. Under their long hegemony, there has been a tendency to assume biological causation without question, and to accept social explanations only under the duress of a siege of irresistible evidence. In political questions, this tendency favored a do-nothing policy.” Or, as Condorcet said more succinctly a long time ago: they “make nature herself an accomplice in the crime of political inequality.”

  This book seeks to demonstrate both the scientific weaknesses and political contexts of determinist arguments. Even so, I do not intend to contrast evil determinists who stray from the path of scientific objectivity with enlightened antideterminists who approach data with an open mind and therefore see truth. Rather, I criticize the myth that science itself is an objective enterprise, done properly only when scientists can shuck the constraints of their culture and view the world as it really is.

  Among scientists, few conscious ideologues have entered these debates on either side. Scientists needn’t become explicit apologists for their class or culture in order to reflect these pervasive aspects of life. My message is not that biological determinists were bad scientists or even that they were always wrong. Rather, I believe that science must be understood as a social phenomenon, a gutsy, human enterprise, not the work of robots programed to collect pure information. I also present this view as an upbeat for science, not as a gloomy epitaph for a noble hope sacrificed on the altar of human limitations.

  Science, since people must do it, is a socially embedded activity. It progresses by hunch, vision, and intuition. Much of its change through time does not record a closer approach to absolute truth, but the alteration of cultural contexts that influence it so strongly. Facts are not pure and unsullied bits of information; culture also influences what we see and how we see it. Theories, moreover, are not inexorable inductions from facts. The most creative theories are often imaginative visions imposed upon facts; the source of imagination is also strongly cultural.

  This argument, although still anathema to many practicing scientists, would, I think, be accepted by nearly every historian of science. In advancing it, however, I do not ally myself with an overextension now popular in some historical circles: the purely relativistic claim that scientific change only reflects the modification of social contex
ts, that truth is a meaningless notion outside cultural assumptions, and that science can therefore provide no enduring answers. As a practicing scientist, I share the credo of my colleagues: I believe that a factual reality exists and that science, though often in an obtuse and erratic manner, can learn about it. Galileo was not shown the instruments of torture in an abstract debate about lunar motion. He had threatened the Church’s conventional argument for social and doctrinal stability: the static world order with planets circling about a central earth, priests subordinate to the Pope and serfs to their lord. But the Church soon made its peace with Galileo’s cosmology. They had no choice; the earth really does revolve about the sun.

  Yet the history of many scientific subjects is virtually free from such constraints of fact for two major reasons. First, some topics are invested with enormous social importance but blessed with very little reliable information. When the ratio of data to social impact is so low, a history of scientific attitudes may be little more than an oblique record of social change. The history of scientific views on race, for example, serves as a mirror of social movements (Provine, 1973). This mirror reflects in good times and bad, in periods of belief in equality and in eras of rampant racism. The death knell of the old eugenics in America was sounded more by Hitler’s particular use of once-favored arguments for sterilization and racial purification than by advances in genetic knowledge.

  Second, many questions are formulated by scientists in such a restricted way that any legitimate answer can only validate a social preference. Much of the debate on racial differences in mental worth, for example, proceeded upon the assumption that intelligence is a thing in the head. Until this notion was swept aside, no amount of data could dislodge a strong Western tradition for ordering related items into a progressive chain of being.

 

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