Although he vacillated early in his career, Morton soon became a leader among the American polygenists. He wrote several articles to defend the status of human races as separate, created species. He took on the strongest claim of opponents—the interfertility of all human races—by arguing from both sides. He relied on travelers’ reports to claim that some human races—Australian aborigines and Caucasians in particular—very rarely produce fertile offspring (Morton, 1851). He attributed this failure to “a disparity of primordial organization.” But, he continued, Buffon’s criterion of interfertility must be abandoned in any case, for hybridization is common in nature, even between species belonging to different genera (Morton, 1847, 1850). Species must be redefined as “a primordial organic form” (1850, p. 82). “Bravo, my dear Sir,” wrote Agassiz in a letter, “you have at last furnished science with a true philosophical definition of species” (in Stanton, 1960, p. 141). But how to recognize a primordial form? Morton replied: “If certain existing organic types can be traced back into the ‘night of time,’ as dissimilar as we see them now, is it not more reasonable to regard them as aboriginal, than to suppose them the mere and accidental derivations of an isolated patriarchal stem of which we know nothing?” (1850, p. 82). Thus, Morton regarded several breeds of dogs as separate species because their skeletons resided in the Egyptian catacombs, as recognizable and distinct from other breeds as they are now. The tombs also contained blacks and Caucasians. Morton dated the beaching of Noah’s Ark on Ararat at 4,179 years before his time, and the Egyptian tombs at just 1,000 years after that—clearly not enough time for the sons of Noah to differentiate into races. (How, he asks, can we believe that races changed so rapidly for 1,000 years, and not at all for 3,000 years since then?) Human races must have been separate from the start (Morton, 1839, p. 88).
But separate, as the Supreme Court once said, need not mean unequal. Morton therefore set out to establish relative rank on “objective” grounds. He surveyed the drawings of ancient Egypt and found that blacks are invariably depicted as menials—a sure sign that they have always played their appropriate biological role: “Negroes were numerous in Egypt, but their social position in ancient times was the same that it is now, that of servants and slaves” (Morton, 1844, p. 158). (A curious argument, to be sure, for these blacks had been captured in warfare; sub-Saharan societies depicted blacks as rulers.)
But Morton’s fame as a scientist rested upon his collection of skulls and their role in racial ranking. Since the cranial cavity of a human skull provides a faithful measure of the brain it once contained, Morton set out to rank races by the average sizes of their brains. He filled the cranial cavity with sifted white mustard seed, poured the seed back into a graduated cylinder and read the skull’s volume in cubic inches. Later on, he became dissatisfied with mustard seed because he could not obtain consistent results. The seeds did not pack well, for they were too light and still varied too much in size, despite sieving. Remeasurements of single skulls might differ by more than 5 percent, or 4 cubic inches in skulls with an average capacity near 80 cubic inches. Consequently, he switched to one-eighth-inch-diameter lead shot “of the size called BB” and achieved consistent results that never varied by more than a single cubic inch for the same skull.
Morton published three major works on the sizes of human skulls—his lavish, beautifully illustrated volume on American Indians, the Crania Americana of 1839; his studies on skulls from the Egyptian tombs, the Crania Aegyptiaca of 1844; and the epitome of his entire collection in 1849. Each contained a table, summarizing his results on average skull volumes arranged by race. I have reproduced all three tables here (Tables 2.1 to 2.3). They represent the major contribution of American polygeny to debates about racial ranking. They outlived the theory of separate creations and were reprinted repeatedly during the nineteenth century as irrefutable, “hard” data on the mental worth of human races (see p.i 16). Needless to say, they matched every good Yankee’s prejudice—whites on top, Indians in the middle, and blacks on the bottom; and, among whites, Teutons and Anglo-Saxons on top, Jews in the middle, and Hindus on the bottom. Moreover, the pattern had been stable throughout recorded history, for whites had the same advantage over blacks in ancient Egypt. Status and access to power in Morton’s America faithfully reflected biological merit. How could sentimentalists and egalitarians stand against the dictates of nature? Morton had provided clean, objective data based on the largest collection of skulls in the world.
Table 2.1 Morton's summary table of cranial capacity by race
Table 2.2 Cranial capacities for skulls from Egyptian tombs
During the summer of 1977 I spent several weeks reanalyzing Morton’s data. (Morton, the self-styled objectivist, published all his raw information. We can infer with little doubt how he moved from raw measurements to summary tables.) In short, and to put it bluntly, Morton’s summaries are a patchwork of fudging and finagling in the clear interest of controlling a priori convictions. Yet—and this is the most intriguing aspect of the case—I find no evidence of conscious fraud; indeed, had Morton been a conscious fudger, he would not have published his data so openly.
Conscious fraud is probably rare in science. It is also not very interesting, for it tells us little about the nature of scientific activity. Liars, if discovered, are excommunicated; scientists declare that their profession has properly policed itself, and they return to work, mythology unimpaired, and objectively vindicated. The prevalence of unconscious finagling, on the other hand, suggests a general conclusion about the social context of science. For if scientists can be honestly self-deluded to Morton’s extent, then prior prejudice may be found anywhere, even in the basics of measuring bones and toting sums.
Table 2.3 Morton’s final summary of cranial capacity by race
The case of Indian inferiority: Crania Americana*
Morton began his first and largest work, the Crania Americana of 1839, with a discourse on the essential character of human races. His statements immediately expose his prejudices. Of the “Greenland esquimaux,” he wrote: “They are crafty, sensual, ungrateful, obstinate and unfeeling, and much of their affection for their children may be traced to purely selfish motives. They devour the most disgusting aliments uncooked and uncleaned, and seem to have no ideas beyond providing for the present moment.… Their mental faculties, from infancy to old age, present a continued childhood.… In gluttony, selfishness and ingratitude, they are perhaps unequalled by any other nation of people” (1839, p. 54). Morton thought little better of other Mongolians, for he wrote of the Chinese (p. 50): “So versatile are their feelings and actions, that they have been compared to the monkey race, whose attention is perpetually changing from one object to another.” The Hottentots, he claimed (p. 90), are “the nearest approximation to the lower animals.… Their complexion is a yellowish brown, compared by travellers to the peculiar hue of Europeans in the last stages of jaundice.… The women are represented as even more repulsive in appearance than the men.” Yet, when Morton had to describe one Caucasian tribe as a “mere horde of rapacious banditti” (p. 9), he quickly added that “their moral perceptions, under the influence of an equitable government, would no doubt assume a much more favorable aspect.”
Morton’s summary chart (Table 2.1) presents the “hard” argument of the Crania Americana. He had measured the capacity of 144 Indian skulls and calculated a mean of 82 cubic inches, a full 5 cubic inches below the Caucasian norm (Figs. 2.4 and 2.5). In addition, Morton appended a table of phrenological measurements indicating a deficiency of “higher” mental powers among Indians. “The benevolent mind,” Morton concluded (p. 82), “may regret the inaptitude of the Indian for civilization,” but sentimentality must yield to fact. “The structure of his mind appears to be different from that of the white man, nor can the two harmonize in the social relations except on the most limited scale.” Indians “are not only averse to the restraints of education, but for the most part are incapable of a continued process of reasoning
on abstract subjects” (p. 81).
Since Crania Americana is primarily a treatise on the inferior quality of Indian intellect, I note first of all that Morton’s cited average of 82 cubic inches for Indian skulls is incorrect. He separated Indians into two groups, “Toltecans” from Mexico and South America, and “Barbarous Tribes” from North America. Eighty-two is the average for Barbarous skulls; the total sample of 144 yields a mean of 80.2 cubic inches, or a gap of almost 7 cubic inches between Indian and Caucasian averages. (I do not know how Morton made this elementary error. It did permit him, in any case, to retain the conventional chain of being with whites on top, Indians in the middle, and blacks on the bottom.)
But the “correct” value of 80.2 is far too low, for it is the result of an improper procedure. Morton’s 144 skulls belong to many different groups of Indians; these groups differ significantly among themselves in cranial capacity. Each group should be weighted equally, lest the final average be biased by unequal size of subsamples. Suppose, for example, that we tried to estimate average human height from a sample of two jockeys, the author of this book (strictly middling stature), and all the players in the National Basketball Association. The hundreds of Jabbars would swamp the remaining three and give an average in excess of six and a half feet. If, however, we averaged the averages of the three groups (jockeys, me, and the basketball players), then our figure would lie closer to the true value. Morton’s sample is strongly biased by a major overrepresentation of an extreme group—the small-brained Inca Peruvians. (They have a mean cranial capacity of 74.36 cubic inches and provide 25 percent of the entire sample). Large-brained Iroquois, on the other hand, contribute only 3 skulls to the total sample (2 percent). If, by the accidents of collecting, Morton’s sample had included 25 percent Iroquois and just a few Incas, his average would have risen substantially. Consequently, I corrected this bias as best I could by averaging the mean values for all tribes represented by 4 or more skulls. The Indian average now rises to 83.79 cubic inches.
2.4 The skull of an Araucanian Indian. The lithographs of this and the next figure were done by John Collins, a great scientific artist unfortunately unrecognized today. They appeared in Morton’s Crania Americana of 1839.
2.5 The skull of a Huron Indian. Lithograph by John Collins from Morton’s Crania Americana, 1839.
This revised value is still more than 3 cubic inches from the Caucasian average. Yet, when we examine Morton’s procedure for computing the Caucasian mean, we uncover an astounding inconsistency. Since statistical reasoning is largely a product of the last one hundred years, I might have excused Morton’s error for the Indian mean by arguing that he did not recognize the biases produced by unequal sizes among subsamples. But now we discover that he understood this bias perfectly well—for Morton calculated his high Caucasian mean by consciously eliminating small-brained Hindus from his sample. He writes (p. 261): “It is proper, however, to mention that but 3 Hindoos are admitted in the whole number, because the skulls of these people are probably smaller than those of any other existing nation. For example, 17 Hindoo heads give a mean of but 75 cubic inches; and the three received into the table are taken at that average.” Thus, Morton included a large subsample of small-brained people (Inca Peruvians) to pull down the Indian average, but excluded just as many small Caucasian skulls to raise the mean of his own group. Since he tells us what he did so baldly, we must assume that Morton did not deem his procedure improper. But by what rationale did he keep Incas and exclude Hindus, unless it were the a priori assumption of a truly higher Caucasian mean? For one might then throw out the Hindu sample as truly anomalous, but retain the Inca sample (with the same mean as the Hindus, by the way) as the lower end of normality for its disadvantaged larger group.
I restored the Hindu skulls to Morton’s sample, using the same procedure of equal weighting for all groups. Morton’s Caucasian sample, by his reckoning, contains skulls from four subgroups, so Hindus should contribute one-fourth of all skulls to the sample. If we restore all seventeen of Morton’s Hindu skulls, they form 26 percent of the total sample of sixty-six. The Caucasian mean now drops to 84.45 cubic inches, for no difference worth mentioning between Indians and Caucasians. (Eskimos, despite Morton’s low opinion of them, yield a mean of 86.8, hidden by amalgamation with other subgroups in the Mongol grand mean of 83). So much for Indian inferiority.
The case of the Egyptian catacombs: Crania Aegyptiaca
Morton’s friend and fellow polygenist George Gliddon was United States consul for the city of Cairo. He dispatched to Philadelphia more than one hundred skulls from tombs of ancient Egypt, and Morton responded with his second major treatise, the Crania Aegyptiaca of 1844. Morton had shown, or so he thought, that whites surpassed Indians in mental endowment. Now he would crown his story by demonstrating that the discrepancy between whites and blacks was even greater, and that this difference had been stable for more than three thousand years.
Morton felt that he could identify both races and subgroups among races from features of the skull (most anthropologists today would deny that such assignments can be made unambiguously). He divided his Caucasian skulls into Pelasgics (Hellenes, or ancient Greek forebears), Jews, and Egyptians—in that order, again confirming Anglo-Saxon preferences (Table 2.2). Non-Caucasian skulls he identified either as “negroid” (hybrids of Negro and Caucasian with more black than white) or as pure Negro.
Morton’s subjective division of Caucasian skulls is clearly unwarranted, for he simply assigned the most bulbous crania to his favored Pelasgic group and the most flattened to Egyptians; he mentions no other criteria of subdivision. If we ignore his threefold separation and amalgamate all sixty-five Caucasian skulls into a single sample, we obtain an average capacity of 82.15 cubic inches.(If we give Morton the benefit of all doubt and rank his dubious sub-samples equally—as we did in computing Indian and Caucasian means for the Crania Americana—we obtain an average of 83.3 cubic inches.)
Either of these values still exceeds the negroid and Negro averages substantially. Morton assumed that he had measured an innate difference in intelligence. He never considered any other proposal for the disparity in average cranial capacity—though another simple and obvious explanation lay before him.
Sizes of brains are related to the sizes of bodies that carry them: big people tend to have larger brains than small people. This fact does not imply that big people are smarter—any more than elephants should be judged more intelligent than humans because their brains are larger. Appropriate corrections must be made for differences in body size. Men tend to be larger than women; consequently, their brains are bigger. When corrections for body size are applied, men and women have brains of approximately equal size. Morton not only failed to correct for differences in sex or body size; he did not even recognize the relationship, though his data proclaimed it loud and clear. (I can only conjecture that Morton never separated his skulls by sex or stature—though his tables record these data—because he wanted so much to read differences in brain size directly as differences in intelligence.)
Many of the Egyptian skulls came with mummified remains of their possessors (Fig. 2.6), and Morton could record their sex unambiguously. If we use Morton’s own designations and compute separate averages for males and females (as Morton never did), we obtain the following remarkable result. Mean capacity for twenty-four male Caucasian skulls is 86.5 cubic inches; twenty-two female skulls average 77.2 (the remaining nineteen skulls could not be identified by sex). Of the six negroid skulls, Morton identified two as female (at 71 and 77 cubic inches) and could not allocate the other four (at 77, 77, 87, and 88).* If we make the reasonable conjecture that the two smaller skulls (77 and 77) are female, and the two larger male (87 and 88), we obtain a male negroid average of 87.5, slightly above the Caucasian male mean of 86.5, and a female negroid average of 75.5, slightly below the Caucasian value of 77.2. The apparent difference of 4 cubic inches between Morton’s Caucasian and negroid samples may only record the fact t
hat about half his Caucasian sample is male, while only one-third the negroid sample may be male. (The apparent difference is magnified by Morton’s incorrect rounding of the negroid average down to 79 rather than up to 80. As we shall see again, all of Morton’s minor numerical errors favor his prejudices.) Differences in average brain size between Caucasians and negroids in the Egyptian tombs only record differences in stature due to sex, not variation in “intelligence.” You will not be surprised to learn that the single pure Negro skull (73 cubic inches) is a female.
2.6 Skulls from the Egyptian catacombs. From Morton’s Crania Aegyptiaca of 1844.
Table 2.4 Cranial capacity of Indian groups ordered by Morton’s assessment of body stature
The correlation of brain and body also resolves a question left hanging in our previous discussion of the Crania Americana: What is the basis for differences in average brain size among Indian peoples? (These differences bothered Morton considerably, for he could not understand how small-brained Incas had built such an elaborate civilization, though he consoled himself with the fact of their rapid conquest by the conquistadores). Again, the answer lay before him, but Morton never saw it. Morton presents subjective data on bodily statures in his descriptions of the various tribes, and I present these assessments along with average brain sizes in Table 2.4. The correlation of brain and body size is affirmed without exception. The low Hindu mean among Caucasians also records a difference in stature, not another case of dumb Indians.
The Mismeasure of Man Page 9