The Politics of Pigmentation

In the sixth essay of the Legacies of Eugenics series, Suman Seth explores the anti-history of the evolution of whiteness.

By Suman SethNovember 29, 2024

• Science & Technology

• History

This is the sixth installment in the Legacies of Eugenics series, which features essays by leading thinkers devoted to exploring the history of eugenics and the ways it shapes our present. The series is organized by Osagie K. Obasogie in collaboration with the Los Angeles Review of Books, and supported by the Center for Genetics and Society, the Othering & Belonging Institute, and Berkeley Public Health.

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ABOUT 100 YEARS separates the publication of Charles Darwin’s On the Origin of Species (1859) and Mary Leakey’s discovery of an extinct human ancestor at Olduvai Gorge in Tanzania. Across that century, debates raged over when and where our species first crossed the line from animals to Homo and then on to Homo sapiens. While a European origin seemed to fit with the discovery of Neanderthal fossils in Germany, other finds in Java and China appeared to point to an Asian source. Remarkably consistent across this same period, however, was the assumption that early humans were of an intermediate physical hue. In his enormously popular book Up from the Ape, first published in 1931 (with a second edition in 1946), Harvard professor of anthropology Earnest Albert Hooton insisted that a “generalized White race was the earliest form of Homo sapiens.” “Everyone agrees,” he added, “that early generalized and prototypical Whites must have had light brown skins, dark hair, and dark eyes.” Mutations and natural selection then led to variations in either direction, with blondness and albinism “discriminated against least in cool, temperate regions” and dark skin being selected for in the tropics.

Popular culture echoed the same themes. In H. G. Wells’s 1921 short story “The Grisly Folk,” the author imagined an encounter between “our ancestors”—whom he calls “true men”—and Neanderthals, depicting the latter as “perhaps bristly or hairy in some queer inhuman fashion like the hairy elephant and the woolly rhinoceros who were his contemporaries.” The first true men, by contrast, “would be a brownish brown-eyed people with wavy dark hair; the fairness of the European and the straight blue-black hair of the Chinaman had still to be evolved in the world.” Readers of a certain age will likely remember devouring the novels of Jean M. Auel, beginning with The Clan of the Cave Bear (1980), in which short, stocky, brown-haired and brown-eyed Neanderthals adopt a pale, blue-eyed Homo sapiens girl with “hair that had once been nearly white.”

Auel’s series may have been the last blockbuster to portray our closest ancestors as blonds. On January 1, 1987, Nature published a paper arguing that all current human mitochondrial DNA derived from a single population in Africa between 100,000 and 200,000 years ago. The press ran with stories of a “mitochondrial Eve” who was the mother of us all, while Newsweek famously produced a cover story depicting a dark-skinned Adam and Eve in a luscious Garden of Eden. The “Out of Africa” hypothesis has by now become firmly rooted.

When trying to establish whether an event occurred or a practice was common, historians love to quote an old adage: absence of evidence is not evidence of absence. It’s a good point. There are lots of reasons why the historical record might be spotty, untrustworthy, or even silent. That observation, however, should not make us overlook fairly straightforward cases where a question went largely unasked because other questions seemed much more reasonable or appropriate.

The set of ideas about temperate originality that I analyze here profoundly shaped the eugenics movement and lasted well past its ostensible end. Indeed, for about 97 percent of the last 2,500 years, it was taken as a given that the people of temperate climates were either made in the image of God(s) or else that they had evolved separately from their darker or lighter brothers and sisters. Only in the last roughly three percent of that time has it become standard to assume that humans were originally black-skinned and that middling hues were a late addition to the human fold. That we were so oblivious to an idea we now consider so obvious may be the most basic evidence we have for the existence and persistence of Eurocentrism and racism in science.

Indeed, when we think about “race” in science, we think of acts of commission: what people do to other people because of something dubbed “race.” Less horrific perhaps but no less consequential are acts of omission: questions that go unasked, in part because of racialist assumptions. In this essay, I track an absence—a largely unasked question—that prevailed for two and a half millennia: why did the inhabitants of temperate Europe, Central Asia, and the Middle East have the middling skin color they did? As noted, for most of Western history, it was assumed that such people were made in the image of God(s), and so this color was a divinely ordained base color, the original from which other skin tones were at best deviations and at worst degenerations.

Now, however, it seems obvious that we need to ask what biological advantage lighter skin, which developed over time, may have conferred in the struggle for survival. The very obviousness of the question makes the obliviousness of our forebears stand out. As we grapple with the legacies of racism today, their obliviousness should compel us to ask what other fundamental questions we’re omitting.

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The August 15, 1959, issue of Nature contained a worldview-altering article with a generic title. In “A New Fossil Skull from Olduvai,” archaeologist and anthropologist Louis Leakey announced that his wife Mary had found a fossil hominid skull at the site, which he described as representing “one of the earliest Hominidae, with the Olduvai skull as the oldest yet discovered maker of stone tools.” A headline in The Times from early September trumpeted the “claim that 600,000-year-old skull is ‘Missing Link.’” What made the find so inordinately newsworthy were its age and location: the Leakeys had found it on the “wrong” continent; it was evidence that the earliest Homo sapiens had inhabited Africa, not Europe or Asia.

The find was met with skepticism in some quarters. In 1962, Carleton Coon—professor of anthropology at the University of Pennsylvania—published The Origin of Races, which laid out his theory that the five races of men had evolved separately. Homo erectus, he argued, “evolved into Homo sapiens not once but five times, as each subspecies, living in its own territory, passed a critical threshold from a more brutal to a more sapient state.” By Coon’s account, the Caucasoid or white race had evolved 200,000 years earlier—and hence had been evolving “upward” for much longer—than the Congoid or Black race.

His arguments—developed in part through many conversations with his cousin, the dedicated racist and segregationist Carleton Putnam—were adopted with alacrity by segregationists in the South: they were delighted to find “scientific evidence” for their cause in the midst of the Civil Rights Movement. Coon insisted that a “true” Homo sapiens had not really been discovered in Africa. The skull, he rationalized, was just a “very primitive form” of the species, and thus of lesser consequence. And “if Africa was the cradle of mankind,” he wrote, “it was only an indifferent kindergarten. Europe and Asia,” he concluded, “were our principal schools.”

The politically progressive wing of American anthropology, which was dominant by the mid-1960s, had the opposite response: it embraced the Leakeys’ logic with pleasure. One of its members, University of Michigan professor of anthropology C. Loring Brace, wrote a popular essay in 1970 postulating an “African origin for all mankind.” He went on to note in the essay that the “Middle Pleistocene ancestors of all modern men were probably what in America today is called black,” and then explained that the use of clothing in colder climates eventually reduced the significance of pigmentation as protection from the sun and “produced the phenomenon that is euphemistically called white.”

In a 1972 review of the extant literature, two dermatologists and an anthropologist joined the fray. They landed squarely on the progressive side, posing the unasked question at issue here: “[T]he usual question is, Why is the Negro black? It is equally important to ask, Why does the Caucasoid branch of Homo sapiens include men with the lightest skin, hair, and eye color?” One explanation, which had been percolating in the literature for a while, involved vitamin D—isolated in 1922, with its deficiency identified as the cause of rickets. A particularly observant physician in Iowa named Frederick G. Murray seized on a subsequent string of remarkable studies detailing three cures for rickets: cod liver oil (rich in the vitamin), exposure to sunlight, and exposure to ultraviolet waves produced by a mercury-vapor quartz lamp. This was relatively uncontroversial. Murray—far more controversially—connected this information with a fact that he claimed had “long been recognized”—namely that “infants of the colored race in the United States are more predisposed to rickets than are the white babies.” Dark skin, he surmised in 1934, offered additional resistance to the UV rays that produced vitamin D. And in the deep past, those with heavily pigmented skin would have been selected against in regions with low levels of sunlight.

During the ensuing decades, the vitamin D hypothesis was merely one explanation among many others—e.g., dark skin’s protection against skin diseases, its role as camouflage or in providing thermoregulation, its sensitivity to frostbite, and so on. A 1982 paper showed that six times as much UV radiation was required for a “Negro” patient to achieve vitamin D levels comparable to a “Caucasian” one. And yet the skepticism continued. A decade later, in 1991, Ashley Robins of the University of Cape Town Medical School claimed that, yes, the vitamin D hypothesis was “now widely embraced in evolutionary thinking,” but, no, it “does not survive critical scrutiny” because the body can store vitamin D in summer months to survive winter ones. Rickets, Robins argued, was not a disease that would have emerged during the “open-air, hunter-gatherer lifestyle of naked or semi-naked Homo on the Eurasian and North American landscapes during the Pleistocene.”

Robins is worth mentioning because he alluded to one more piece of evidence, albeit only in passing, that ended up proving crucial. This was the folate theory. Folate, very sensitive to UV radiation, is understood to have negative impacts on survival and reproduction, which the other explanations, vitamin D included, failed to account for.

It’s at this point that Nina Jablonski enters the picture, with a new interpretation of both the scientific and the social data on skin color. An anthropologist who had focused on nonhuman primates early in her career, she moved over to studying humans in the 1990s, during which decade she published a paper on the evolution of menopause, another on the origin of hominid bipedalism, and a third—most crucially for her eventual research—on the relationship between UV radiation, skin color, and neural tube defects (NTDs, birth defects of the brain and spinal cord). Ultraviolet light, she argued, caused folate depletion in pregnant women, leading to birth defects such as spina bifida. In 1997, she put forward her version of the folate thesis. “From an evolutionary point of view,” she wrote, “melanized skin pigment in humans and other vertebrates may now be traced to its photoprotective role in reducing ultraviolet-light induced photolysis of folate and NTDs resulting from severe folate depletion.” A paper published the following year, which pointed to experimental evidence that UV irradiation of amphibian larvae led to developmental defects, once again stressed the value of dark skin for human evolution.

In 2000, Jablonski and her husband and collaborator, George Chaplin, published a paper that theorized a series of processes by which first dark and then light human skin had evolved. The first process involved our species losing the body hair characteristic of our closest primate ancestors. For Darwin, hair loss had been another characteristic, like skin color, that natural selection could not explain. “No one supposes,” he had written in 1871, “that the nakedness of the skin is of any direct advantage to man, so that his body cannot have been divested of hair through natural selection.” It is now believed, however, that hair loss was coupled with ever-denser sweat glands, which meant that the human body became vastly better at evaporative cooling. Indeed, humans possess “the most effective body cooling system of any mammal.” That newly denuded or partly denuded skin, however, now needed protection from full-on exposure to sunlight.

This leads to the second process: darkly pigmented integuments must have evolved in tandem to protect exposed skin from ultraviolet-induced photolysis of folate. Then, there was a third evolutionary process: when humans left Africa and journeyed into Northern Europe, Murray’s mechanism kicked in, and members of the population with lighter skin were selected for on the basis that they produced greater amounts of vitamin D in cloudy and low UV radiation conditions.

In varied genres and forms, Jablonski and Chaplin have been arguing for their new pigmentation paradigm for a quarter of a century. Jablonski in particular has been making the case for an understanding of skin color that rejects colorism. Like many of those anthropologists who made up the progressivist wing of the field in the 1950s and ’60s, she is aware that race and racism are hard to tease apart. More significant than any genetic effects on human health, she and Chaplin noted in 2017, “are the problems of social segregation and behavioural bias that are rooted in cultural constructions of skin colour-based race categories.” The “sepia rainbow of human skin colours,” she insists, should unite rather than divide us.

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With our contemporary view established, we can now turn to the past. Skin color was one of many features that ancient Greeks and Romans believed was shaped by both environment and diet. To the fifth-century BC Hippocratic author of “On Airs, Waters, and Places,” these aspects of one’s home molded the body, mind, and political system. The original color of humans was left unremarked, although from the etymology of the word “Ethiopian” (from the Greek for “burnt face”), we can deduce the basic assumption. Those with dark skin, then, were essentially those of middling hues who had been transformed by bright African sunlight. In the first century AD, Pliny the Elder made clear the moral and physical superiority of those who occupied the Mediterranean (i.e., the middle of the world):

It is not in doubt that the Ethiopians are burned by the heat of the sun, which is nearer to them, and are born like burned people with their beards and hair frazzled. On the opposite and icy side of the world there are peoples with white skin and light-colored hair. The latter races are wild because of the cold, the former lackluster because of the weather’s fickleness. […]

But in the middle of the world there is a healthy mixture of hot and cold. The lands are fertile for all things, and the people’s bodies appear moderate in size and color because of this proper mixture.

Within Christendom, this climatic logic was coupled with an Old Testament narrative that had all people descending from Adam and Eve, and then dispersing throughout the world after the Fall. A first dispersion was followed by a second, when humans were punished for their sins with a flood that killed all but Noah and his family. From Noah’s three sons (Ham, Shem, and Japheth) were assumed to flow all current peoples—our term “Semitic” derives from the name of one of Noah’s progeny. Precisely where Eden or Mount Ararat (where Noah’s ship eventually alighted) were to be found was, of course, a contested question, but there was general agreement that it was not in sub-Saharan Africa, East Asia, or parts of the world north of the Arctic Circle. Dwellers in those regions, then, had acquired their physical features over several millennia.

The European “discovery” of the Americas did not change this fundamental logic. Precisely how Noah’s descendants had populated these lands was a puzzle for several Renaissance scholars. The Dutch humanist Hugo Grotius, for example, proposed that northern Native Americans had descended from Germans, most South Americans from Southeast Asians, Peruvians from Chinese, and those from the Yucatan Peninsula from Ethiopians. The notion that emigration might have gone the other way was not, so far as I am aware, ever raised. Amerindian physical features, on the other hand, required no great intellectual complexities. According to Jean de Léry, for example, who spent time in the late 16th century with the Tupinambá in Brazil, the people around him were “not particularly dark” given the climate of their home. They were, he observed, “of a tawny shade, like the Spanish or Provençals.”

By the late 16th century, the French historian Jean Bodin could offer a numerically precise latitudinal map of skin coloration. “Under the Tropics,” he wrote, “[people] are unusually black; under the pole, for the opposite reason, they are tawny in colour.” Here, the word “unusually” signaled that neither of these shades are to be taken as original. “[D]own to the sixtieth parallel,” he continued, “they become ruddy; thence to the forty-fifth they are white […] to the thirtieth they become yellow.”

The climatic theory remained the dominant paradigm for explaining racial difference until well into the 19th century. Anomalies had, however, emerged much earlier, inspired by data gleaned from further exploration as well as observations made on the millions of enslaved peoples forced into bondage through the transatlantic trade. On one hand, the mapping between latitude and color was inconsistent: people occupying roughly the same bands of the earth were not the same shade, and people of the same color could be found in dramatically different locations. The forced migrations due to the slave trade, meanwhile, drew into question the climate theory’s transformational assumptions. If one took the Bible literally—and most did—Noah’s Ark had set down roughly 4,000 years earlier. In the subsequent time, the progeny of three brothers needed to have traveled the earth and become modified by their new homes. Skin color, by this logic, changed very quickly. And it was assumed that it could drift in either direction. Light people in hot climates would darken and those of blacker hues would become pale.

And yet, the children of people of African descent who now lived in cold climates did not seem to be lightening. In the words of the English polymath Thomas Browne in 1646, “Negroes transplanted, although into cold and flegmatick habitations, continue their hue both in themselves, and also their generations; except they mix with different complexions.” Or, as Isaac Newton’s contemporary Robert Boyle put it in 1664, “good authors inform us, that the offspring of Negroes transplanted out of Africa, above a hundred years ago, retain still the complexion of their progenitors.”

For a small minority of thinkers, these and other problems with the climate theory were enough to overthrow biblical orthodoxy entirely. Perhaps, they mused, turning an old heresy to new purpose, all men were not derived from the same original pair. Perhaps there were men before Adam, or at least multiple special creations, with each race made de novo, looking as they did today in the regions in which they were currently found? The iconoclastic French philosophe Voltaire, for example, declared in 1734 that “none but the blind can doubt that the Whites, the Negroes, the Albinos, the Hottentots, the Laplanders, the Chinese, and the Americans, are races entirely different” and that “the same providence which placed men in Norway, also fixed some in America and in the southern polar circle; in the same manner as it has planted trees and shrubs, and causes the grass to grow there.” Few were willing to follow Voltaire down this heterodox path. In 1775, Johann Friedrich Blumenbach, a German physician and naturalist, described his French colleague as “witty” but “badly instructed in physiology.”

A dedicated proponent of the climate theory, Blumenbach is responsible for the word “Caucasian.” One of the five fundamental races of humankind that he eventually proposed, Caucasians were, he was sure, the race or type most likely to represent the original, of which the others were deviations. The point is worth emphasizing. While the classical world had taken temperate climates and middling tones as the likely first origin and color of mankind, scholars and naturalists of the European Enlightenment shifted this origin north. The region around Mount Caucasus in Eastern Europe, Blumenbach insisted, produced “the most beautiful race of men,” those who had degenerated least from an Edenic original. The skull of a Georgian woman was the loveliest he possessed, “from which, as from a mean and primeval type, the others diverge by most easy gradations on both sides to the two ultimate extremes (that is, on the one side the Mongolian, on the other the Ethiopian).”

What was true of the internal structure was also true of the external. White skin, Blumenbach argued, was “the primitive colour of mankind, since […] it is very easy for that to degenerate into brown, but very much more difficult for dark to become white.” Immanuel Kant, who offered his own theory in 1775, was less convinced that the climate alone could produce racial diversity. He believed, like Voltaire, that the races were not interconvertible, and yet he disdained the possibility of discarding human unity. Instead, he imagined that all humans had been created once upon a time with the capacity to take on different forms. Starting in the same place, they spread across the globe until they reached the four corners of the earth. At that point, the seeds they carried within came to fruition, and they became the four races—noble blond, copper red, black, and olive yellow—that populate the planet today. From that point, no further drastic modifications were possible: each race was now fixed. The original human variety, meanwhile—which Kant took to be “White of brownish color”—was now forever lost.

How deeply this assumption of an original whiteness or temperate lightness was ingrained in Western thought can be illustrated through two examples from this period. In 1799, Benjamin Rush, Philadelphia’s most famous physician and a signer of the Declaration of Independence, attempted to derive black skin color from a form of congenital leprosy. Although he knew that ancient sources had associated leprosy with “preternatural whiteness,” Rush took the writings of a single Spanish author as decisive in showing that one variety of the dread disease produced skin that was “black, thick, and greasey.” For Rush, this unsavory origin demanded paternalistic benevolence: “If the color of the negroes be the effect of a disease,” he insisted, “instead of inviting us to tyrannise over them, it should entitle them to a double portion of our humanity, for disease all over the world has always been the signal for immediate and universal compassion.”

Roughly a dozen years later, James Cowles Prichard—who would become the leading light of British ethnology—proposed an equally audacious and nonclimatic explanation for the color of African skin. Perhaps, he suggested, skin lightened with increasing levels of civilization? The theory tracked with the arrogance of an imperial age, but it also carried with it a radical corollary: the first humans—who, for the orthodox Prichard, could only have been Adam and Eve—were, by this logic, Black. Prichard did not have the courage of his convictions. Faced with a barrage of criticisms, later editions of his text walked back this assumption, restoring humanity’s parents to their paler state.

Of course, the debate around the puzzle of human beginnings changed dramatically after Charles Darwin’s publication of On the Origin of Species and especially The Descent of Man, and Selection in Relation to Sex (1871). The latter contains the oft-quoted claim that “man is descended from a hairy quadruped, furnished with a tail and pointed ears, probably arboreal in its habits, and an inhabitant of the Old World.” While this might suggest that our closest animal forebears were to be found in Africa, the enormous length of time that separated the emergence of humans from our simian ancestors left open the problem of where on the globe this may have first happened. As for the conundrum of human skin coloration, Darwin himself rejected natural selection as an explanation, something that isn’t acknowledged nearly enough. Indeed, as he phrased it, “not one of the external differences between the races of man are of any direct or special service to him.” Hence, none could be selected in the struggle for survival.

That climate could not explain skin color, claimed Darwin, had first been established in the late 18th century, and “almost all anthropologists” of his time had accepted the point. The arguments were the ones we have seen already: racial distributions did not accord with climatic variations, and colors seemed not to change even over the span of centuries. Early in his career, Darwin had believed that darker skin might be correlated with immunity to certain diseases. “Assume that a dusky individual best escapes miasma,” he wrote to Alfred Russel Wallace in 1864, “and you will readily see what I mean.” By 1871, however, his attempts to find evidence for this supposition had proven fruitless, and so, instead, he proposed sexual selection as the mechanism through which racial differences had first emerged. Differences in skin color, or amounts of bodily hair, in other words, were a matter of sexual preference and helped determine mate choice. In Darwin’s words, “the colour of the skin is regarded by […] all races as a highly important element in their beauty; so that it is a character which would be likely to be modified through selection.”

As in the earlier theory regarding disease immunity, Darwin seemed to believe that here, too, the question to be answered involved only the origins of dark skin. “It seems at first sight a monstrous supposition,” he wrote with striking Eurocentrism, “that the jet blackness of the negro has been gained [my emphasis] through sexual selection; but this view is supported by various analogies, and we know that negroes admire their own blackness.” Even so radical a thinker as Darwin, in other words, appeared to struggle to imagine that the causes of his own skin tone might need explanation or justification.

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When I was growing up as a child of Indian parents in Australia, I was often told that racism was about ignorance. As an adult who has now worked on the history of race for more than two decades, I’ve come to find that claim less and less reasonable—and even, I think, wrong and condescending. The idea that racists could be convinced of their errors if only we could sit them down and show them tables and statistics, literature and data, is risible. Racisms are not absences of evidence but rather “presences” of information that we need to refute; they are made up of layers and layers of often mutually reinforcing assumptions and claims, experiences and narratives. We need to treat racist claims as arguments in their own right and combat them as we would any other arguments.

But that combat cannot be done only with scientific information. For when we think about the scientific arguments against racism—and there are many—we too often fall into the trap of assuming that the issue is one of data alone. As I have shown in this essay, however, better answers to extant questions are not the only things we need. It has become common to belittle the humanities for their irrelevance to the modern world, and in particular to mock the value of humanities-derived tools such as “critical thinking.” Yet perhaps the most important part of our method is not only to argue for better answers but also to ask whether our questions are in fact the right ones. With the benefit of hindsight, we can now see that racial and ethnocentric assumptions blinded us for two millennia to what we now think of as the correct question concerning pigmentation. Moving forward, we need to think—ever more carefully and critically—about other questions we’ve left unchallenged for far too long.

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Featured image: Cover of Newsweek, January 11, 1988. Image has been cropped.