The Mismeasure of Man
Stephen Jay Gould
Acknowledgments
Page 14
ENES MAY BE SELFISH in a limited metaphorical sense, but there can be no gene for selfishness when I have so many friends and colleagues willing to offer their aid
The frame of The Mismeasure of Man
Page 16
Great Is Our Sin—from Darwin’s line, cited as an epigraph on my title page: “If the misery of our poor be caused not by the laws of nature, but by our institutions, great is our sin.”
Page 18
You have to sneak up on generalities, not assault them head-on
Why revise The Mismeasure of Man after fifteen years?
Page 38
When causative factors (more than two, by the way) interact so complexly, and throughout growth, to produce an intricate adult being, we cannot, in principle, parse that being’s behavior into quantitative percentages of remote root causes.
Page 38
The truly salient issues are malleability and flexibility, not fallacious parsing by percentages. A trait may be 90 percent heritable, yet entirely malleable. A twenty-dollar pair of eyeglasses from the local pharmacy may fully correct a defect of vision that is 100 percent heritable. A “60 percent” biodeterminist is not a subtle interactionist, but a determinist on the “little bit pregnant” model.
Page 41
If good arguments cannot transcend time, then we might as well throw out our libraries.
Reasons, history and revision of The Mismeasure of Man
Page 41
It is dangerous for a scholar even to imagine that he might attain complete neutrality, for then one stops being vigilant about personal preferences and their influences—and then one truly falls victim to the dictates of prejudice.
Page 42
The best form of objectivity lies in explicitly identifying preferences so that their influence can be recognized and countermanded.
Page 54
I was proud when Mismeasure won the National Book Critics Circle award in nonfiction,
Note: todo: read the list, looking for interesting books to read
1. Introduction
Page 68
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.
Page 70
But science’s potential as an instrument for identifying the cultural constraints upon it cannot be fully realized until scientists give up the twin myths of objectivity and inexorable march toward truth. One must, indeed, locate the beam in one’s own eye before interpreting correctly the pervasive motes in everybody else’s. The beams can then become facilitators, rather than impediments.
Page 71
We therefore give the word “intelligence” to this wondrously complex and multifaceted set of human capabilities. This shorthand symbol is then reified and intelligence achieves its dubious status as a unitary thing.
Preevolutionary styles of scientific racism: monogenism and polygenism
Page 91
Buffon himself, the greatest naturalist of eighteenth-century France, was a strong abolitionist and exponent of improvement for inferior races in appropriate environments. But he never doubted the inherent validity of a white standard: The most temperate climate lies between the 40th and 50th degree of latitude, and it produces the most handsome and beautiful men. It is from this climate that the ideas of the genuine color of mankind, and of the various degrees of beauty ought to be derived.
Introduction
Page 136
Science is rooted in creative interpretation. Numbers suggest, constrain, and refute; they do not, by themselves, specify the content of scientific theories. Theories are built upon the interpretation of numbers, and interpreters are often trapped by their own rhetoric. They believe in their own objectivity, and fail to discern the prejudice that leads them to one interpretation among many consistent with their numbers.
Page 136
Paul Broca is now distant enough. We can stand back and show that he used numbers not to generate new theories but to illustrate a priori conclusions.
The dismantling of Binet’s intentions in America
Page 243
But variation among individuals within a group and differences in mean values between groups are entirely separate phenomena. One item provides no license for speculation about the other. A hypothetical and noncontroversial example will suffice. Human height has a higher heritability than any value ever proposed for IQ. Take two separate groups of males. The first, with an average height of 5 feet 10 inches, live in a prosperous American town. The second, with an average height of 5 feet 6 inches, are starving in a third-world village. Heritability is 95 percent or so in each place—meaning only that relatively tall fathers tend to have tall sons and relatively short fathers short sons. This high within-group heritability argues neither for nor against the possibility that better nutrition in the next generation might raise the average height of third-world villagers above that of prosperous Americans. Likewise, IQ could be highly heritable within groups, and the average difference between whites and blacks in America might still only record the environmental disadvantages of blacks.
CAN DEMOCRACY SURVIVE AN AVERAGE MENTAL AGE OF THIRTEEN?
Page 334
“We cannot conceive of any worse form of chaos than a real democracy in a population of average intelligence of a little over 13 years.”
Note: this is eerily prescient: idiocracy!
The case of Sir Cyril Burt
Page 356
The principal error, in fact, has involved a major theme of this book: reification—in this case, the notion that such a nebulous, socially defined concept as intelligence might be identified as a “thing” with a locus in the brain and a definite degree of heritability—and that it might be measured as a single number, thus permitting a unilinear ranking of people according to the amount of it they possess.
Correlation and cause
Page 357
Much of the fascination of statistics lies embedded in our gut feeling—and never trust a gut feeling—that abstract measures summarizing large tables of data must express something more real and fundamental than the data themselves.
Page 358
The standard measure of correlation is called Pearson’s product moment correlation coefficient or, for short, simply the correlation coefficient, symbolized as r. The correlation coefficient ranges from +1 for perfect positive correlation, to 0 for no correlation, to -1 for perfect negative correlation* In rough terms, r measures the shape of an ellipse of plotted points (see Fig. 6.1). Very skinny ellipses represent high correlations—the skinniest of all, a straight line, reflects an r of 1.0. Fat ellipses represent lower correlations, and the fattest of all, a circle, reflects zero correlation (increase in one measure permits no prediction about whether the other will increase, decrease, or remain the same).
Page 361
In summary, most correlations are noncausal; when correlations are causal, the fact and strength of the correlation rarely specifies the nature of the cause.
The error of reification
Page 370
Causal reasons lie behind the positive correlations of most mental tests. But what reasons? We cannot infer the reasons from a strong first principal component any more than we can induce the cause of a single correlation coefficient from its magnitude. We cannot reify g as a “thing” unless we have convincing, independent information beyond the fact of correlation itself.
Page 370
Spearman’s g is particularly subject to ambiguity in interpretation, if only because the two most contradictory causal hypotheses are both fully consistent with it: 1) that it reflects an inherited level of mental acuity (some people do well on most tests because they are born smarter); or 2) that it records environmental advantages and deficits (some people do well on most tests because they are well schooled, grew up with enough to eat, books in the home, and loving parents). If the simple existence of g can be theoretically interpreted in either a purely hereditarian or purely environmentalist way, then its mere presence—even its reasonable strength—cannot justly lead to any reification at all. The temptation to reify is powerful. The idea that we have detected something “underlying” the externalities of a large set of correlation coefficients, something perhaps more real than the superficial measurements themselves, can be intoxicating. It is Plato’s essence, the abstract, eternal reality underlying superficial appearances. But it is a temptation that we must resist, for it reflects an ancient prejudice of thought, not a truth of nature.
Rotation and the nonnecessity of principal components
Page 373
In short, factor analysis simplifies large sets of data by reducing dimensionality and trading some loss of information for the recognition of ordered structure in fewer dimensions. As a tool for simplification, it has proved its great value in many disciplines. But many factorists have gone beyond simplification, and tried to define factors as causal entities. This error of reification has plagued the technique since its inception. It was “present at the creation” since Spearman invented factor analysis to study the correlation matrix of mental tests and then reified his principal component asg- or innate, general intelligence. Factor analysis may help us to understand causes by directing us to information beyond the mathematics of correlation. But factors, by themselves, are neither things nor causes; they are mathematical abstractions.
Spearman’s reification o/g
Page 393
My complaint lies with the practice of assuming that the mere existence of a factor, in itself, provides a license for causal speculation. Factorists have consistently warned against such an assumption, but our Platonic urges to discover underlying essences continue to prevail over proper caution
Page 393
Automatic reification is invalid for two major reasons. First, as I discussed briefly on pp. 282–285 and will treat in full on pp. 326–347, no set of factors has any claim to exclusive concordance with the real world. Any matrix of positive correlation coefficients can be factored, as Spearman did, in to g and a set of subsidiary factors or, as Thurstone did, into a set of “simple structure” factors that usually lack a single dominant direction. Since either solution resolves the same amount of information, they are equivalent in mathematical terms. Yet they lead to contrary psychological interpretations. How can we claim that one, or either, is a mirror of reality? Second, any single set of factors can be interpreted in a variety of ways. Spearman read his strong g as evidence for a single reality underlying all cognitive mental activity, a general energy within the brain. Yet Spearman’s most celebrated English colleague in factor analysis, Sir Godfrey Thomson, accepted Spearman’s mathematical results but consistently chose to interpret them in an opposite manner. Spearman argued that the brain could be divided into a set of specific engines, fueled by a general energy. Thomson, using the same data, inferred that the brain has hardly any specialized structure at all. Nerve cells, he argued, either fire completely or not at all—they are either off or on, with no intermediary state
Page 394
If the same mathematical pattern can yield such disparate interpretations, what claim can either have upon reality?
A final thought
Page 465
The tendency has always been strong to believe that whatever received a name must be an entity or being, having an independent existence of its own. And if no real entity answering to the name could be found, men did not for that reason suppose that none existed, but imagined that it was something peculiarly abstruse and mysterious. JOHN STUART MILL
7. A Positive Conclusion
Page 466
I do not regard this book as a negative exercise in debunking, offering nothing in return once the errors of biological determinism are exposed as social prejudice. I believe that we have much to learn about ourselves from the undeniable fact that we are evolved animals. This understanding cannot permeate through entrenched habits of thought that lead us to reify and rank—habits that arise within social contexts and support them in return. My message, as I hope to convey it at least, is strongly positive for three major reasons
Debunking as positive science
Page 466
Debunking as positive science
Page 466
The idea of unilinear progress not only lies behind the racial rankings that I have criticized as social prejudice throughout this book; it also suggests a false concept of how science develops. In this view, any science begins in the nothingness of ignorance and moves toward truth by gathering more and more information, constructing theories as facts accumulate. In such a world, debunking would be primarily negative, for it would only shuck some rotten apples from the barrel of accumulating knowledge. But the barrel of theory is always full; sciences work with elaborated contexts for explaining facts from the very outset. Creationist biology was dead wrong about the origin of species, but Cuvier’s brand of creationism was not an emptier or less-developed world view than Darwin’s. Science advances primarily by replacement, not by addition. If the barrel is always full, then the rotten applies must be discarded before better ones can be added. Scientists do not debunk only to cleanse and purge. They refute older ideas in the light of a different view about the nature of things.
Learning by Debunking
Page 467
Learning by debunking
Page 469
if the holocaust comes and a small tribe deep in the New Guinea forests are the only survivors, almost all the genetic variation now expressed among the innumerable groups of our five billion people will be preserved.
Page 469
This information about limited genetic differences among human groups is useful as well as interesting, often in the deepest sense—for saving lives. When American eugenicists attributed diseases of poverty to the inferior genetic construction of poor people, they could propose no systematic remedy other than sterilization. When Joseph Goldberger proved that pellagra was not a genetic disorder, but a result of vitamin deficiency among the poor, he could cure it.
Biology and human nature
Page 470
Biology and human nature
Page 470
The impact of human uniqueness upon the world has been enormous because it has established a new kind of evolution to support the transmission across generations of learned knowledge and behavior. Human uniqueness resides primarily in our brains. It is expressed in the culture built upon our intelligence and the power it gives us to manipulate the world. Human societies change by cultural evolution, not as a result of biological alteration. We have no evidence for biological change in brain size or structure since Homo sapiens appeared in the fossil record some fifty thousand years ago.
Page 472
We now believe that different attitudes and styles of thought among human groups are usually the nongenetic products of cultural evolution. In short, the biological basis of human uniqueness leads us to reject biological determinism. Our large brain is the biological foundation of intelligence; intelligence is the ground of culture; and cultural transmission builds a new mode of evolution more effective than Darwinian processes in its limited realm—the “inheritance” and modification of learned behavior. As philosopher Stephen Toulmin stated (1977, p. 4): “Culture has the power to impose itself on nature from within.”
Page 480
Human uniqueness lies in the flexibility of what our brain can do. What is intelligence, if not the ability to face problems in an unprogramed (or, as we often say, creative) manner?
Disingenuousness of program
Page 504
I closed Chapter 7 in The Mismeasure of Man on the unreality of g and the fallacy of regarding intelligence as a single innate thing-in-the-head (rather than a rough vernacular term for a wondrous panoply of largely independent abilities) with a marvelous quote from John Stuart Mill, well worth repeating to debunk this generation’s recycling of biological determinism for the genetics of intelligence: The tendency has always been strong to believe that whatever received a name must be an entity or being, having an independent existence of its own. And if no real entity answering to the name could be found, men did not for that reason suppose that none existed, but imagined that it was something particularly abstruse and mysterious.
Ghosts of Bell Curves past
Page 513
The “Gobinist” version of mental testing—using the enterprise to argue for innate and ineradicable differences in general intelligence among human groups—relies upon four sequential and interrelated premises; each must be true individually (and all the linkages must hold as well), or else the entire edifice collapses:
- The wonderfully multifarious and multidimensional set of human attributes that we call “intelligence” in the vernacular must all rest upon a single, overarching (or undergirding) factor of general intellectual capacity, usually called g, or the general factor of intelligence (see my critique of this notion and its mathematical basis in Chapter 7 of the main text).
Page 513
- The general “amount” of intelligence in each person must be measurable as a single number (usually called “IQ”); a linear ranking of people by IQ must therefore establish a hierarchy of differential intelligence; and, finally (for the social factor in the argument), people’s achievements in life, and their social ranks in hierarchies of worth and wealth, must be strongly correlated with their IQ scores.
Page 514
- This single number must measure an inborn quality of genetic constitution, highly heritable across generations.
- A person’s IQ score must be stable and permanent—subject to little change (but only minor and temporary tinkering) by any program of social and educational intervention.
Page 514
In other words, to characterize each of the four arguments in a word or two, human intelligence must be abstractable (as a single number), rankable, highly heritable, and effectively immutable
Page 514
If any of these assumptions fails, the entire argument and associated political agenda go belly up. For example, if only the fourth premise of immutability is false, then social programs of intense educational remediation may well boost, substantially and permanently, an innate and highly heritable disadvantage in IQ—just as I may purchase a pair of eyeglasses to correct an entirely inborn and fully heritable defect of vision. (The false equation of “heritable” with “permanent” or “unchangeable” has long acted as a cardinal misconception in this debate.)
Page 516
Binet explicitly denied that his test—later called an intelligence quotient (or IQ) when the German psychologist W. Stern scored the results by dividing “mental age” (as ascertained on the test) by chronological age—could be measuring an internal biological property worthy of the name “general intelligence.”
Page 516
First of all, Binet believed that the complex and multifarious property called intelligence could not, in principle, be captured by a single number capable of ranking children in a linear hierarchy. He wrote in 1905: 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.
Page 516
Moreover, Binet feared that if teachers read the IQ number as an inflexible inborn quality, rather than (as he intended) a guide for identifying students in need of help, they would use the scores as a cynical excuse for expunging, rather than aiding, troublesome students. Binet wrote of such teachers: “They seem to reason in the following way: ‘Here is an excellent opportunity for getting rid of all the children who trouble us,’ and without the true critical spirit, they designate all who are unruly, or disinterested in the school.”
Page 517
Binet also feared the powerful bias that has since been labeled “self-fulfilling prophecy” or the Pygmalion effect: if teachers are told that a student is inherently uneducable based on misinterpretation of low IQ scores, they will treat the student as unable, thereby encouraging poor performance by their inadequate nurture, rather than the student’s inherent nature. Invoking the case then racking France, Binet wrote: It is really too easy to discover signs of backwardness in an individual when one is forewarned. This would be to operate as the graphologists did who, when Dreyfus was believed to be guilty, discovered in his handwriting signs of a traitor or a spy.
Page 518
Binet avoided any claim about inborn biological limits because he knew that an innatist interpretation (which the test scores didn’t warrant in any case) would perversely destroy his aim of helping children with educational problems.
Page 518
Binet took pleasure in the successes of teachers who did use his tests to identify students and provide needed help. He defended remedial programs and insisted that gains so recorded must be read as genuine increases in intelligence: It is in this practical sense, the only one accessible to us., that we say that the intelligence of these children has been increased. We have increased what constitutes the intelligence of a pupil: the capacity to learn and to assimilate instruction
Note: I was tested when i was about 9 years old. Because of my good results i was supposed to go to a higher grade classroom for English and Math. But this attenpt to help me backfired because I would leave my normal classroom and stay in the schoolyard instead of going to the higher grade classroom.
My grandfather was tested when he came to Los Angeles as a teenager. He told the teacher: I am not dumb. The test is just asking the wrong questions!
Page 520
Intelligence, Binet told us, cannot be abstracted as a single number. IQ is a helpful device for identifying children in need of aid, not a dictate of inevitable biology. Such aid can be effective, for the human mind is, above all, flexible. We are not all equal in endowment, and we do not enter the world as blank slates, but most deficiencies can be mediated to a considerable degree, and the palling effect of biological determinism defines its greatest tragedy—for if we give up (because we accept the doctrine of immutable inborn limits), but could have helped, then we have committed the most grievous error of chaining the human spirit. Why must we follow the fallacious and dichotomous model of pitting a supposedly fixed and inborn biology against the flexibility of training—or nature vs. nurture in the mellifluous pairing of words that so fixes this false opposition in the public mind? Biology is not inevitable destiny; education is not an assault upon biological limits. Rather, our extensive capacity for educational improvement records a genetic uniqueness vouchsafed only to humans among animals.
Page 522
Biology is not the enemy of human flexibility, but the source and potentiator (while genetic determinism represents a false theory of biology). Darwinism is not a statement about fixed differences, but the central theory for a discipline—evolutionary biology—that has discovered the sources of human unity in minimal genetic distances among our races and in the geological yesterday of our common origin.
The moral state of Tahiti—and of Darwin
Page 571
Finally, think about one more Darwinian line—perhaps the greatest—from the slavery chapter in the Voyage of the Beagle. We learn about diversity in order to understand, not simply to accept: If the misery of our poor be caused not by the laws of nature, but by our institutions, great is our sin.