A Four-Letter Word Called "Race"

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October/November 2000

Originally prepared for:

Race and Other Miscalculations, and Mismeasures:

Papers in Honor of Ashley Montagu

L. J. Reynolds and L. Lieberman (eds.)

General Hall, Publishers

Dix Hills, N.Y.

Prologue

The very genesis of the field of biological anthropology was rooted in the assumption that there are valid biological entities that can be called “races,” and that these then are legitimate targets of anthropological study. Biological anthropologists have often been somewhat slower than others to realize that those “entities” do not have coherent biological reality. This has been particularly true in America where the concept of “race” was more an ancillary result of the circumstances of the human settlement of the hemisphere and how this affected the way people think about things than a consequence of the study of the real nature and dimensions of human biological variation.

The first biological anthropologist in America to bring this to the attention of the reading public was a transplanted Englishman, Ashley Montagu, who settled in the United States in 1930, the very year that I was born, and has remained here ever since (Brace, 1997). Montagu’s most influential work, Man’s Most Dangerous Myth: The Fallacy of Race (Montagu, 1942), has had a turbulent history. In the past, much of biological anthropology tended to treat it as though it were a manifestation of what we now refer to as P.C. -- political correctness -- in this case a kind of ‘feel-good’ manifestation of liberal wishful thinking (for example, Shipman, 1994; but see the critique of that by Brace, 1995).

The approach may indeed be compatible with liberal social thought, but it is actually based on a solid grasp of the biological nature of human variation. As the synthetic theory of evolution began to have its impact on some parts of biological anthropology in the decade after the end of World War II, there were some who realized that we could only make real biological sense out of the nature of human variation after the concept of “race” was junked and we started over from scratch. I was one of the people who came to that realization when I started teaching at the Santa Barbara campus of the University of California. I had been able to get Ashley Montagu to speak to our undergraduate anthropology club there, and I was successful in getting him brought to the campus in 1963 as Regent’s Lecturer for our winter term. In turn he invited me to contribute a chapter for the volume, The Concept of Race, that he was editing to appear in 1964 (Brace, 1964). In that chapter, I tried to show how to handle the study of the nature of human biological variation after the “race” concept had been dispensed with.

That was a third of a century ago, however, and there has been more than a bit of back-sliding in the world of biological anthropology. With that in mind, Larry Reynolds and Leonard Lieberman, of Central Michigan University, prepared a volume of essays in honor of Ashley Montagu’s ninetieth year, and, to my great pleasure, they invited me to be one of the contributors. This gave me the opportunity to completely revamp and update the approach I had taken in 1964 with the addition of the quantities of information and insight that have accumulated since that time. Actually since so many biological anthropologists still have not gotten much beyond the point of trying to justify the application of “racial” names to human individuals and groups, the information relating to the distribution of the separate aspects of human adaptation has not accumulated as rapidly as it could have. Hope springs eternal, and, this time around, just maybe the idea will take root and a new generation will actually go and get the information we need to document the picture of which I present here in outline form (Brace, 1996).

When I presented a version of this to the Canadian Association of Physical Anthropologists in Windsor, Ontario, on October 28, 1994, I was able to get the assistance of Humbert O. Echo, another member of that extraordinary faculty in the Department of Homopathic Anthropopoetics at the University of Southern North Dakota at Hoople. Echo had previously been of assistance by rendering some of the gambits I have essayed in versified form, and he had allowed me to use that particular piece as an addendum to a comment, “What shall we call ‘Them’?” that I published in 1996 (Echo, 1996). This is attached here:

The Name of a Race

When we ponder on the contours in the features of a face

That resembles all the others which are from a given place;

What potential harm would follow if we use a single name,

To denote a group of people when we think they look the same?

But there are no implications that a common shape will bear,

Beyond the clear reminder of the kinship that they share;

For selection’s not delimited by groups of kin alone,

Or confined within the boundaries of a continental zone.

Pigment in the skin will give protection from the sun,

But it doesn’t give a clue to how another trait will run;

But the desert and the artic take the moisture from the air,

And people from both places have a nose of length to spare.

Features cannot tell us who is mad and who is sane,

Or nuance of the forehead say a thing about the brain.

Each trait that is adaptive will pursue a separate course,

Determined by the nature of its own selective force

Which crosses all the others in a fashion that defines

A pattern without meaning made of independent clines.

Since each selected feature has a different place of birth,

The mix within a region can have no collective worth.

When thoughtlessly we verbalize without the proper care,

Our words can make an entity that isn’t really there;

How much pigment or how little will suffice to give the right

To warrant the conferral of the label “Black” or “White”?

And beware the added meaning in the tag we lightly give;

For it oftentimes determines who may have the right to live.

Acceptance of the concept, and all that it can mean,

Gives credence to an image that could best be called obscene;

To use the very word is to be captured by its spell:

That which we call a “race,” by any other name would smell…

Sources Cited

Brace, C. Loring, 1964. A Non-Racial Approach Towards the Understanding of Human Diversity. In Ashley Montagu (ed.), The Concept of Race. The Free Press of Glencoe, New York. pp. 103-152.

Brace, C. Loring, 1995. Review of The Evolution of Racism: Human Differences and the Use and Abuse of Science, by Pat Shipman. American Journal of Physical Anthropology 96(2):204-210.

Brace, C. Loring, 1996. A Four-Letter Word Called Race. In Larry T. Reynolds and Leonard Lieberman (eds.), Race and Other Misadventures: Essays in Honor of Ashley Montagu in His Ninetieth Year. General Hall, Publishers, Dix Hills, New York. pp. 106-141.

Brace. C. Loring, 1997. Montagu, Ashley (1905- ). In Frank Spencer (ed.), History of Physical Anthropology: An Encyclopedia. Garland, New York. pp. 683-685.

Montagu, Ashley, 1942. Man’s Most Dangerous Myth: The Fallacy of Race. Columbia University Press, New York. 216 pp.

Shipman, Pat, 1994. The Evolution of Racism: Human Differences and the Use and Abuse of Science. Simon & Schuster, New York. 318 pp.

Abstract

Human biological variation is real, and its study is a most interesting subject. However, we can make no sense of it if we start with "racial" categories as entities for comparison. Traits that are of importance for human survival are distributed in clinal fashion according to the distribution of the selective forces that govern their expression. Those selective forces, in turn, are not constrained by human population boundaries and cannot be perceived or understood if such boundaries are assumed as the starting points for analysis.

There are traits that are constrained by human population boundaries, and it is these that allow us to recognize the part of the world from which their possessors originally came. Those traits, however, simply constitute 'family resemblance writ large' end have no adaptive significance. Population samples will cluster with their nearest neighbors because they share the genetic background for such adaptively unimportant traits. The best way to refer to people who display the configuration characteristic of the clusters of population samples that come from the same region is to use geographical designations. Thus people can be identified as African, or Australian, or European and the like. More precise localization can be achieved by using modifiers such as West African, Eastern European, and Southeast Asian among any others.

Data relating to the distribution of Hemoglobin S, skin color and tooth size are presented to show how each responds to the varying intensity of the particular selective force controlling its manifestation. The independence of the clines associated with each one demonstrates the futility of trying to use a concept such as "race" to understand adaptively important human biological characteristics. Finally, the case of intelligence is considered, and it is noted that, while no human population today is living under the circumstances that shaped the common human condition during the Pleistocene, it is still largely true that it takes at least as much intelligence to survive and contribute to the next generation in one part of the world as it does in another. Since the conditions governing the emergence of our extraordinary human brain power were essentially everywhere the same during the long period of time when human intelligence was evolving, it follows that the intellectual capabilities of the various living human populations in the world are now also everywhere the same. Those who continue to advocate the value of investigating "racial" difference in intelligence, then, are evidently driven by a subjective desire to demonstrate that difference is to be expected. At bottom, that expectation is simply a manifestation of racism.

Introduction

All good people agree,

And all good people say,

All nice people, like us, are We

And everyone else is they.

Rudyard Kipling, We and They

The issues dealt with here are so important that they should transcend the involvement and pronouncements of any single individual or school of thought. If there is a possible exception to that generalization, it would have to be illustrated by the life and work of Ashley Montagu For more than half a century now, he has stood for the view that "race" is not only a "myth," but that it is our "Most Dangerous Myth," to quote from the title of one of his most influential books first written in 1942. The insights in that seminal work remain as true today as when he first phrased them, and they can serve as a solid point of departure for my own efforts in this paper written to celebrate the career and accomplishments of the author of that signal contribution. This gives me the opportunity to update my own first attempt (Brace 1964) to deal with the question of "race" written some thirty years ago at the specific request of the very person in whose honor I am writing now -- Ashley Montagu.

I am going to begin with the conclusion: "race" is a social construct derived mainly from perceptions conditioned by the events of recorded history, and it has no basic biological reality. Quite simply, there is no useful entity that corresponds to what is popularly intended by the term "race." This was explicitly noted in regard to the case of Americans of African ancestry by no less a figure than the late Gunnar Myrdal — that extraordinary Swedish economist and author of one of the most perceptive books ever written about the way things are in the United States, An American Dilemma (1944:115). To much of the reading public, this will seem like a complete absurdity. The average literate citizen of the western world reacts with frank disbelief when told that there is no such thing as “race.” “Why, it's as plain as the nose on your face!” is one of the partially facetious reactions. When the anthropologist continues to insist that there is no human biological category that can be called "race," the skeptical layman will shake his head and just regard this as further evidence of the innate silliness of those who call themselves intellectuals.

This feeling has been seconded by some biological anthropologists who have gone so far as to say that denials of the biological reality of "race" are simply the products of their well-meaning colleagues' abhorrence of the ills and injustices that have arisen in its name. In this view, the denial that "race" has a biological reality is itself the result of socially conditioned perceptions. Myrdal, for instance, was a social scientist and not recognized as an authority on biological matters. However well-intentioned they may be, then, such denials themselves presumably have no biological justification and therefore lack validity. The cry of both professional and non-professional skeptics goes like this: ‘If there are no “races,” how come people are so good at identifying them?’ (and see how that rhetorical question is asked -- and answered! -- in Sauer 1992).

But what is this "them" that we are so good at recognizing? It is true that people are reasonably good at being able to tell what part of the world someone comes from in a general kind of way. Unless a person has parents from very different parts of the world, it is not hard to tell whether a person's family roots were in eastern Asia, western Europe, or southern India. In addition, most Americans would feel confident that they could detect the presence of African ancestry, although in fact they are quite unable to tell whether a person comes from West Africa or the eastern end of New Guinea. There are reasons for that particular confusion which will be treated later, but, although it introduces a touch of uncertainty, it does not really blunt the general conviction that it is not all that difficult to tell at a glance the part of the world from which a person's ancestors originally came.

Traditional "Races"

So far, however, I have said nothing about "race" — I have just mentioned the characteristic appearance associated with geographic areas. Well, you may ask, why isn't that recognizable appearance an indicator of the presence of something legitimately called "race"? To answer that, we have to come to grips with what it is that produces those configurations that we can associate with given areas, and we have to consider the biological significance of each such configuration.

One of the most enduring schemes of "racial" designation divides the peoples of the world into three large categories crudely conceptualized as "black," "white," and "yellow;" or in more orotund and polysyllabic form, "Negroid," "Caucasoid," and "Mongoloid." Early in the 19th century, this scheme was advocated by Georges Cuvier (1769-1832), one of the most influential figures in the history of French science, although it was neither original with him nor was it offered in anything more than the most casual of terms (Cuvier 1817:1:94; 1829:1:80). Some of Cuvier's readers interpreted these three "races" as the respective descendants of the three sons of the Biblical Noah — Ham, Shem, and Japheth (Murray 1834:255; Morton 1839:2).

For many of the beneficiaries of the traditions of "western civilization," this formulation was eminently satisfying because it drew strength from its apparent roots in the Bible, the most honored written work in existence in the minds of the Christian faithful who made up the overwhelming majority of the representatives of that "western civilization." In addition, it evoked the sanctity of what westerners regarded as that most mystically sacred of quantities, the number three — also long associated with the Christian "Trinity" even though that baffling concept can only be vaguely and somewhat tortuously squeezed out of the actual phraseology of the Bible.

Now let us take a closer look at what it is that makes us think that we can understand something about human variation if we divide the world up into those three categories. Are they really comparable in the sense of being equally distinctive? And is there something about each that justifies its identification as a category, and what is the biological significance of that "something" if indeed it exists?

Negroid

The very name "Negroid" derives from the Latin word for black — niger — and the word used to denote that color in modern Italian, Spanish and Portuguese is negro. Because southern Europe is closer to Africa than the other European countries, it was inevitable that contacts between the peoples of southern Europe and Africa began earlier and were carried on more continuously than was true between Africans and more northerly European nations. Eventually when northern Europeans extended their contacts towards the south, they tended to adopt the terms already in use by their Mediterranean neighbors. Early in the history of English involvement in the growing trade of enslaved Africans, and long before there were any English-speaking settlers in the western Hemisphere, the term "Negro" entered the English language to mean a native inhabitant of the African continent south of the Sahara (Pope-Hennessy 1968:46). The identification of native Africans as "Negroes" served to focus the attention of would-be categorizers on a single descriptive attribute — skin color. The presence of sufficient melanin in the skin to warrant using a term such as "Negro" or "Black," however, is not restricted to the people of Africa alone. The native inhabitants of southern India, New Guinea and adjacent islands, and northern Australia all possess equivalent amounts of melanin in their skins. If a word meaning "Black" is warranted as a description for people of African origin, then it is also equally appropriate for those others.

The use of the term "Negroid" obviously cannot distinguish between the long-term equatorial inhabitants from one end of the Old World to the other. In fact, melanin in the skin is an adaptation that shields the possessor from the damaging effects of the ultraviolet component of sunlight, and all human populations whose immediate ancestors had been continuous dwellers of the tropics for 100,000 years or more possess that adaptation to an equal extent even if they are only remotely related to each other. As Darwin explicitly realized, any trait that is under the control of selective forces is "almost valueless" for purposes of tracing population relationships (Darwin 1859:427). Obviously a classification based on a trait whose manifestation is under the control of selection will tell us much about the distribution of the relevant selective force, but it will tell us little about the degree of relationship of those populations that display similar degrees of development of the trait in question.

Traditionalists unwilling to give up so soon may raise points concerning the presence of other traits visible in people with elevated levels of melanin in the skin, and suggest that these hang together to indicate the presence of some kind of fundamental underlying entity. Dark skin tends to be associated with tightly curled hair, for example, and dark-skinned people often have large jaws and teeth. However, hair form is the product of the same kinds of selective forces that are associated with skin color. Jaws and teeth, on the other hand, vary according to quite different rules as we shall see later. For the dark-skinned people of New Guinea and Australia, for example, jaw and tooth size actually increases as the intensity of skin pigmentation decreases grading from the North of Australia down to its southern edge (Brace 1980; Brace et al. 1991). Clearly the idea of a "Negroid race" has so many flaws that it is best simply to drop it and start on another tack. More of that later.

Caucasoid

All right, you may say with some reluctance, if an essentially descriptive word does not work to categorize human populations, how about a word that is relatively abstract — "Caucasoid" for example? What could be wrong with using that presumably innocuous term to stand for the people in the northwestern quadrant of human habitation? The history of the application and use of the term "Caucasoid," however, introduces still further problems. The word derives from the Caucasus, that isthmus of land that separates the Black and the Caspian Seas and joins Russia and the Middle East. Its use to denote human physical appearance dates from the "racial" scheme offered by the German physician, Johann Friedrich Blumenbach (1752-1840), in his doctoral dissertation of 1775, De Generis Humani Varietate Nativa (On the Natural Varieties of Mankind) best known from the revised and enlarged third edition of 1795 (translated and edited by Thomas Bendyshe in 1865 and republished in 1969).

The initial reason for the focus on that part of the world was the assumption that, as the Biblical flood subsided, Noah's Ark landed at Mount Ararat in the mountains of the Caucasus. Although the idea was not original with him, Blumenbach claimed that the living people of that region comprise "the most beautiful race of men" with "the most beautiful form of the skull, from which, as from a mean and primeval type, the others diverge by most easy gradations on both sides" (Blumenbach in Bendyshe [ed.] 1865:269). Adding to this assumption of pristine beauty, Blumenbach went on to claim that "white . . . we may fairly assume to have been the primitive colour of mankind" (idem.).

Blumenbach evidently assumed that "Caucasoids" were the least modified descendants of the people who allegedly got off the Ark at Mount Ararat and therefore the best representatives of what God intended when He created human beings in the first place. Other "races" were said to have departed from the form of God's original intent by a process of "degeneration" in proportion to their geographical distance from the mountains of the Caucasus and the differences in the circumstances under which they now find themselves.

I have actually written an overly simplistic synopsis of Blumenbach's thoughtful treatise, and I have left out many of the positive things that it contained. My purpose is not to fault Blumenbach but to highlight the absurdity of the term "Caucasoid." One could go even further by noting that Mount Ararat is actually in Turkish Armenia, and, if there were any justification in using point geographic designations to refer to broadly related human populations, it could be argued that the term "Armenoid" should be preferable to the term "Caucasoid." Of course, the designation "Armenoid" was used for somewhat different purposes in other "racial" classifications a couple of generations ago (Coon 1939:628-629), and this makes it as tainted as "Caucasoid." Again, the best thing to do is to abandon the use of any narrow regional designation as a means of encompassing the perceived similarities of human groups distributed across widespread geographic expanses. The related morphological pattern that we can see running from Scandinavia to the Middle East is poorly served by trying to indicate this by using a narrowly local term, whether that be "Armenoid," "Norwegioid," or "Caucasoid."

Mongoloid

All right, so descriptive terms and narrow regional designations fail to serve our purposes, but what about names derived from human groups? What could be wrong with the use of the term "Mongoloids" to refer to all the related people of eastern Asia? In fact, it has all of the flaws present in narrow regional designations plus some others as well. Just as the Norse or Armenians are inappropriate to use as representatives of all of the people who extend between Norway and Armenia, the Mongols are inappropriate to stand for all of the people who extend from Mongolia to Indonesia.

Adding further less-than-positive connotations to the term "Mongoloid" is the long-time usage of that term to refer to the visible features associated with an inherited syndrome that occurs as a result of irregularities in the transmission of chromosome 21. The first full description was published in 1866 by the English physician, John Langdon Down (Patterson 1987).

When the syndrome recognized by Dr. Down was first described, it was noted that the English children in whom it was observed were afflicted with developmental defects that influenced a series of systems. These included the growth and ossification of the interorbital portion of the face as well as the normally expected path of intellectual maturation. Affected children are also observed to display an alteration in the expected course of pigment production giving a slightly yellowish cast to their appearance. In the European mind, all of these manifestations reminded them of their stereotypic picture of the inhabitants of eastern Asia — flattish of face, yellowish in color and mentally dull and lethargic. The inherited interference with development observed by Dr. Down then was duly labeled "Mongolism" or, in more pejorative fashion, "Mongoloid idiocy." Implicit in this was the feeling that the genetic defect which caused the syndrome was related to the hereditary reasons why the people of eastern Asia differ in general appearance from the people of western Europe. Subsequent generations of geneticists and physicians have recognized the blatant racism behind such attitudes and have sought to correct this by eliminating the term "Mongoloid" from the description of that suite of inherited developmental defects and describing it simply as "Down's syndrome." More recently, the possessive has been eliminated, and it has come to be called "Down syndrome" or "Down disease," and no mention is made of the supposed similarity in appearance between those who are afflicted and the inhabitants of Asia. The memory lingers on in a large segment of the public in the western world, and, if for no other reason, this alone would make the use of the term "Mongoloid" an unfortunate choice of words to describe the population of a major segment of the earth.

However, there is more than just the taint of that racism in the terms of yesteryear to illustrate the fact that the designation "Mongoloid" is misleading at best when used in descriptive fashion. The Mongols, as it happens, display systematic morphological differences from the rest of the people in Asia to such a degree that they could be regarded as the most untypical of that whole set of related populations (Li et al. 1991:278). This is not just an offhanded judgment. A standard set of two dozen craniofacial measurements (the measurements and the techniques used are described at much greater length in Chapters 19 and 20) was made on samples chosen from all the available localities in eastern Asia. These were used to construct a tree diagram — the "dendrogram" shown in Figure 1 — where the length of the stem of each twig is proportional to the morphological relationship with the other twigs to which it is connected. A short stem running from a named twig to the next connecting link means a close relationship. The longer the stem on the twig, the more remote the relationship.

In Figure I, the twig connecting the Mongols to the rest of the samples from eastern Asia is the longest unlinked branch in the entire dendrogram. Other studies using slightly different techniques have come to the same conclusions (Pietrusewsky 1992:42; Pietrusewsky et al. 1992:552). Mongols, then, are as morphologically remote from the other inhabitants of eastern Asia as it is possible to be and yet still count as related (Brace and Tracer 1992:459). To use the Mongols as though they could stand for something essential to all of the related populations of eastern Asia is to run the risk of serious misrepresentation at best. Of course, the assumption that there is some sort of "essence" that we should be looking for is itself fundamentally misguided.

Clines

A generation ago, Frank Livingstone produced the aphorism, "There are no races, there are only clines" (Livingstone 1962:279). This fit in nicely with the assumptions of the neo-Darwinian or synthetic theory of evolution that characterized much of the outlook of the biological sciences that arose in the middle third of the twentieth century. One of the most important figures in that synthesis was the late Sir Ronald A. Fisher (1890-1962), an English biological statistician whose quirky genius occasionally led him into positions of dogmatic intransigence (Box 1978). His long-running feud with the American geneticist, Sewall Wright (1889-1998), was a case in point.

Wright had entertained the possibility that biological evolution could be conditioned by a number of different factors including chance alone — especially when population size is small (Wright 1931). Fisher simply refused to acknowledge the actual mechanisms Wright proposed (Fisher and Ford 1950; Wright 1951). Their argument narrowed down to whether genetic drift could or could not play a role in addition to the effects of natural selection. Fisher had taken the view that selection is all (Fisher 1930), and that in those instances where we could not see how it had its effect, the fault was in our finite and limited powers of observation and understanding. Biologists who accepted this conclusion were put in the position of assuming that all discernible inherited traits and configurations owed their various manifestations to the controlling effects of selection. Our duty, then, was to determine the nature of the selective forces involved and to demonstrate just how these work to control variation in the particular traits that respond to changes in the intensity of their operation. If all traits respond to the graded influence of their particular selective forces, the intersection of their various manifestations to make identifiable configurations in given individuals or populations has no intrinsic significance. This in brief is the intellectual background behind the phrase "there are no races, there are only clines." Whenever separate adaptively significant traits are controlled by separate and unrelated selective forces, this still remains true.

Hemoglobin S

Let me give a concrete example using variation in human populations. Before Livingstone coined that portentous phrase, he had shown that the frequency of the gene for hemoglobin S — the source of human sickle-cell anemia — is controlled by the intensity of infestation with falciparum malaria (Livingstone 1958). Populations in the malarial areas of tropical Africa, the Middle East, and on into India all show high percentages of hemoglobin S even though a certain number of S genes are taken out of circulation each generation because of deaths due to sickle cell anemia.

The distribution of hemoglobin S, then, is unrelated to human population boundaries. It is not an automatic marker for African ancestry as has often been assumed, although many of the Americans who possess it did inherit it from African ancestors. Africa itself probably received hemoglobin S from the Middle East via Arab trade routes across the Sahara, up the Nile, and down the east coast (Livingstone 1989b). The circumstances that led to the infestation by Plasmodium falciparum, the mosquito-transmitted microbe that causes falciparum malaria, are associated with the increase in human population size and the environmental modifications produced by successful agricultural practices in areas where that malaria-producing parasite can flourish. Those areas originally included the tropical, subtropical and temperate parts of the Old World with enough water to allow propagation of the mosquito vector and where the winter was not so severe that they could not survive from one season to the next.

Figure 2 shows the distribution of hemoglobin S in the Old World. In its areas of highest frequency, falciparum malaria also reaches high levels of intensity. If falciparum malaria is the reason for the high frequency of hemoglobin S, one might expect that there would be a one-to-one correlation between malaria intensity and hemoglobin S, but this is not exactly the case. In Southeast Asia, for example, falciparum malaria constitutes a very serious health problem, but hemoglobin S fades out and disappears. The reason for this is the presence of another abnormal hemoglobin — hemoglobin E — which, as it happens, also enables its possessors to cope with malarial infestation but which does not have quite such serious consequences in its homozygous — EE — state (Livingstone 18998a).

Skin color

The abnormal hemoglobins, then, are distributed among the world's populations strictly in accordance with the history of their involvement with malaria of various kinds and without reference to any other manifestations such as geographical, cultural, or political boundaries or anything like face form or pigmentation (Livingstone 1967, 1985). In fact, this is the classic pattern for the distribution of any trait under selective force control. And when we turn to a consideration of pigment, that too shows a pattern of gradation which is independent of the distribution of any other trait not directly related to the intensity of solar radiation. Figure 3 shows the distribution of skin color in the human populations of the world.

Melanin in the skin exists for one purpose only, and that is to prevent the penetration of the ultraviolet component in sunlight. Attempts to suggest that melanin has any relation to mental function — pro or con — are nothing less than unwarranted manifestations of racism (Ortiz de Montellano 1991, 1992). However, it is the 290 to 320 millimicron ultraviolet range, "mid-UV," "middlewave UV" or "UV-B" —.either alone or, as is usually the case, in conjunction with UV-A — that causes the most trouble (Potter 1985; Kligman 1986). The "trouble" caused by UV-B is cancer. Particularly affected are the cells at the bottom of the epidermis at the interface between this layer and the underlying dermis itself. These cells give rise to the outermost portion of the skin in a continued process of renewal that has a three- to-four week turnover (Daniels et al. 1968). UV-B can cause damage that leads to cancer in the basal cells and the derived overlying squamous cells that form the surface of the skin.

In the United States alone in the late 1970's, European Americans contracted over 400,000 cases of basal cell skin cancer which amounted to an incidence of over 232 cases per every 100,000 people. At the same time, less than three-and-one-half cases per 100,000 occurred among Americans of African origin (Ackerman and del Regato 1985:180). At that time, the average number of Americans who died per year from the effects of skin cancer was some 5,000 (interview with Dr. Tim Johnson on ABC television, April 10, 1978).

Carefully designed and controlled laboratory tests have clearly demonstrated the role played by UV-B in leading to skin cancer and have shown that the effects are augmented when both UV-A and UV-B are involved, which of course they are in the case of people and animals exposed to natural sunlight. It has also long been known that "white" skin will allow the penetration of ultraviolet radiation right down through the epidermis to the underlying dermis (Daniels 1969; Kligman 1969; Pathak and Stratton 1969), but that the skin of well-tanned or naturally pigmented individuals will block up to 95% of the penetration of UV-B (Daniels et al. 1968:41; Holick 1987:1879). And in the occasional person of African ancestry in whom a mutation has occurred that blocks the formation of skin pigment — a condition known as albinism — the skin will allow the penetration of ultraviolet radiation in the same manner as in "whites." African albinos are susceptible to skin cancer in the same manner as Europeans (Blum 1959; Friedman et al. 1991:10). From the accumulation of the experimental and clinical evidence, it is impossible to avoid the conclusion that the sole function of melanin in the skin is as the first line of defense against the possible cancer-producing effects of ultraviolet radiation from the sun.

That being the case, the distribution of human skin pigmentation in the world should correspond to the distribution of the intensity of ultraviolet radiation, or, roughly speaking, to latitude: i.e. dark skin color should be concentrated in the tropics where it is adaptively advantageous. From Figure 3, it is clear that the dark- skinned populations of the world are all located in the tropics. However, it is also clear that not all tropic dwellers are dark skinned. The people of mainland Southeast Asia and most of island Indonesia plus the remote islands of Oceania are nowhere near so heavily pigmented as the indigenous populations of tropical Africa, southern India, New Guinea or northern Australia. And finally, there were no indigenous dark-skinned people in the tropics of the western hemisphere.

The obvious reason for this apparent discrepancy is that the relatively light-skinned inhabitants now in those tropical regions must be comparatively recent arrivals. This suspicion is amply confirmed by the evidence available from history, linguistics and archaeology (Benedict 1942; Barth 1952; Bellwood 1979, 1986, 1991; Solheim 1981; Bulbeck 1982). Historical records, for example, show that there has been a continuing movement of peoples southward from the older centers of settled agriculture in China to what had been uncut forest lands in Southeast Asia. Even where there are no written records, the oral traditions of a northern origin and the trail of related languages all tend to confirm this general picture. The web of what is obviously recent linguistic divergence extends all the way out into the islands of the Pacific where archaeology tells us that settlers had reached the Philippines 5,000 year ago but had not gotten as far as Easter Island and Hawaii in Remote Oceania until about 1,500 years ago (Bellwood 1986:107 ff., 1991; Pawley and Green 1973; Tuggle 1979:189).

As for the western hemisphere, although the crucial events occurred long before writing was thought of, and so far back that linguistic evidence is equivocal at best (Nichols 1990:513; Greenberg and Ruhlen 1992:94), archaeology tells us that the first inhabitants came over from the northeast edge of Asia by the end of the Pleistocene almost 12,000 years ago (Haynes 1982:383; Hoffecker et al. 1993:51). The possibility still exists that people may have reached the New World somewhat earlier, but the signs are all tenuous and equivocal. From 11,500 years ago on, however, the evidence is clear and widespread, and it leaves most professional students of the matter with the reasonably comfortable feeling that the ancestors of the "Native Americans" did not arrive in the western hemisphere much before 12,000.

The ancestors of the modern inhabitants of the tropics in Southeast Asia, Polynesia and South America all came from the non-tropical portions of eastern Asia no earlier than the latter part of the Pleistocene. We can assume, then, that the skin color of those ancestors was not significantly different from that of the inhabitants of the temperate parts of eastern Asia today. The reason why they should have been characterized by that particular hue is a different matter that will be considered shortly. For the moment, however, what this tells us is that it takes a lot longer than 10,000 years for the selective effects of UV-B in tropical sunshine to produce the intensity of pigmentation seen in the skin of such modern people as the inhabitants of New Guinea or tropical Africa.

The related question is why people who live in the northern portions of the world have as little skin pigment as they do. All the available fossil and archaeological evidence indicates that ultimate human origins were in the tropics of Africa, and that even after spreading out from that base at the end of the lower Pleistocene a million years ago, humans remained tropic dwellers with only temporary northward forays for much of the rest of their existence (Brace 1991b, and in press). Humans still have the basic physiological characteristics and responses of tropical mammals, and we can guess that the common tropic-dwelling human ancestor of half a million years ago had a degree of skin pigmentation fully comparable to that found today among the inhabitants of equatorial Africa, India and New Guinea. This brings us back to the question of why some modern people are less heavily pigmented than others.

Since all of the long-term inhabitants of the north temperate zone are markedly less pigmented than long-term tropic dwellers, and since we can assume that the common human ancestor was dark, it follows that there must be something about living north of the tropics that leads to a reduction in skin pigment. There are in fact two possible explanations. One suggests that a lessening in the amount of pigment is adaptively advantageous in the north, and the other argues that depigmentation is simply the result of a reduction in the intensity of selection for the maintenance of epidermal melanin.

Those who prefer to see pigment reduction as the result of the positive action of selection point to the evidence indicating that heavily pigmented people are more likely to suffer the effects of vitamin D deficiency in the north temperate zone than is true for people with lesser amounts of skin pigment (Holick 1987). As it happens, those very UV-B wave lengths that lead to skin cancer after prolonged doses are also an essential part of the process that leads to the synthesis of vitamin D. The absorption and incorporation of calcium necessary for proper bone growth is mediated by vitamin D, and a lack of that crucial substance will result in abnormalities and stunting of skeletal development known as rickets.

Rickets, however, is a distinct rarity among the cats, dogs, cows, horses, sheep, rodents, birds and others of the animal world that were native inhabitants of the north temperate zone in spite of the fact that few if any indulged themselves with codfish livers and that the skin in all of these creatures is well protected from any possible ultraviolet penetration by virtue of being thoroughly covered by fur or feathers. There is one more oddity about this whole picture, and this is the fact that there is no pigment in the skin of those thoroughly protected creatures. And finally, it only requires a brief exposure to generate all the vitamin D one needs, and summer sunshine in the north temperate zone is more than adequate even for heavily pigmented skin to provide a supply of Vitamin D that can be stored up in fat and muscle tissue in sufficient quantities to last the rest of the year (Robins 1991:203,205,208).

From my perspective, it would seem that the reason for the absence of pigment in the skin of most furred and feathered creatures is because of the absence of selection for its presence. And I would argue that the same thing may well be true for the human inhabitants of the north temperate zone. Since there is just not enough intensity of UV-B to generate cancers that would shorten possible life spans, there was nothing that would maintain skin pigment at the level which had characterized the tropical forebears of the long-term human inhabitants of the north. A generation ago, I argued that when selection is reduced or suspended, any trait that had been maintained by a formerly active selective force should undergo reduction in proportion to the length of time that selection had been held in abeyance. Under such conditions, the reductions would be the results of mutations alone — a process I referred to as "The Probable Mutation Effect" (Brace 1963).

A more detailed defense of the "PME" is presented elsewhere (Brace et al. 1991 :41-46, and included here as Chapter 10). Here we need only note that those areas where the archaeological evidence indicates that human habitation of the north temperate zone has been continuous for the longest periods of time are also just those areas where modern human populations display the least amount of pigment in the skin. In a zone running from the Middle East to the Atlantic Ocean in northwest Europe, there is reason to believe that human habitation has been continuous for the last 250,000 years (Straus 1989; Mercier et al. 1992). It is in just that stretch where the living inhabitants include people with the least amount of pigmentation among the living populations of the world.

At comparable latitudes in the northeast end of human occupation in the Old World, the continuous archaeological record is only about half as old. From this, it would follow that relaxation of selective pressures to maintain skin pigmentation at fully tropical levels has been in effect only half as long, and depigmentation should not have proceeded to the same extent as in the comparable latitudes in the west. Indeed, the modern inhabitants of Northeast Asia are notably less pigmented than the populations who have continued to live in the tropics without break, but pigment reduction has not proceeded to quite the same extent as that visible at the northwestern edge of the human range. And finally, it only requires a brief exposure to generate all the vitamin D one needs, and summer sunshine in the north temperate zone is more than adequate even for a heavily pigmented skin to provide a supply of Vitamin D that can be stored up in fat and muscle tissue in sufficient quantities to last the rest of the year (Robins 1991:203, 205, 208).

Actually, it does not matter which attempt at explanation is correct since both propose reasons why pigment reduction should occur in areas where ultraviolet radiation is markedly reduced from the levels of its intensity in the tropics. Either would account for the existence and extent of depigmentation in the north temperate zones both east and west in the Old World, and both offer reasons why the relatively recent movement of people from the latitude of China south into Southeast Asia and equatorial Indonesia introduced people with lesser amounts of skin pigmentation than one would otherwise expect to find for people living in the tropics.

At the same time, the movement of agriculturally based populations out of the Middle East during the Neolithic and Bronze Age was predominantly an East-to-West phenomenon rather than a North-to-South one (Brace and Tracer 1992). The result was that the North-to-South gradation or cline in skin color was not disrupted. To this day, skin color grades by imperceptible means from Europe southwards around the eastern end of the Mediterranean and up the Nile into Africa. From one end of this range to the other, there is no hint of a skin color boundary, and yet the spectrum runs from the lightest in the world at the northern edge to as dark as it is possible for humans to be at the equator.

South of the equator, the cline reverses, and skin color becomes lighter away from the tropics towards the south. In Africa, this lightening is more pronounced than the comparable case in Australia, and the aboriginal inhabitants of the southern tip of Africa — the San people once called by the derogatory term "Bushmen" — are no darker than the people by the shores of the Mediterranean who are about the same distance north of the equator as the San are south of it. Skin pigment also lightens towards the south in Australia, but not quite to the same extent as in the African example. Australia, however, has only been occupied for the last 50,000 years (Roberts et al. 1990), and evidently the process of pigment reduction has not had time enough to proceed to the extent evident at the comparable latitudes in Africa.

From all of this, it can be seen that human skin pigmentation is distributed in clinal fashion among those people who have remained in the latitudes where they are found for a period of time on the order of 50,000 years or more. Where skin pigmentation is at variance with our expectations of clinal variation such as Southeast Asia and the New World, we have reason to suspect that such anomalies in human appearance are due to population movements within the last 20,000 years or so. So far, all such suspected instances are confirmed by the available archaeological evidence.

Finally, it is clear that the distributions shown in Figures 2 and 3 are following different sets of rules. Evidently neither one can be understood if one uses the old- fashioned concept of "race" as a starting point, and yet both display vital but unrelated aspects of human biological variation. Each evidently is clinal in nature, but the clines have little to do with each other. Each can be readily understood when studied separately, but the pattern made by the intersection between these two has no "meaning" in and of itself. And when one adds a third trait or a fourth or more, the configurations that emerge tell us nothing whatsoever about the nature and significance of human biological variation.

Tooth Size

The third trait that I am going to deal with is tooth size. It is neither more instructive nor in other ways "better" than any other trait one could use, but it serves the purpose, and I can use the information that I have been collecting myself for the past several decades to demonstrate the nature of modern human tooth size differences.

There has long been a vague kind of perception on the part of European observers that "other races" had larger jaws and teeth than those found in Europe. Along with this perception of greater size in jaw and tooth was a related assumption of smaller size of head and brain. These were interpreted in a hierarchical fashion which assumed European superiority as a given, and the mere presence of a large dentition automatically led to the conclusion that the associated brain was therefore smaller and that the position of the possessor in the world was consequently "lower." None other than the eminent 19th century biologist and defender of Darwin, Thomas Henry Huxley, declared that "no rational man . . . believes that the average negro is the equal, still less the superior, of the average white man." He went on to say that "it is simply incredible that . . . our prognathous relative . . . will be able to compete successfully with his bigger-brained and smaller-jawed rival, in a contest which is to be carried on by thoughts and not by bites" (Huxley 1865:561).

Before I go on to deal with tooth size and the circumstances that relate to size differences between human populations, I should first dispel the idea that large teeth entail small brains. There is absolutely no relationship between brain size and tooth size (Brace et al. 1991:37). As with other traits of adaptive value, the selective forces appropriate to the control of one are completely unrelated to the forces responsible for the control of the other. People do not chew with their brains or think with their teeth. Consequently, variation in one trait is completely unrelated to variation in the other. Second, there is absolutely nothing to sustain the idea that "other" people have smaller brains than Europeans. When brain size is corrected for body size, there is no demonstrable difference between any of the populations of the world (Jensen 1984:54-55; Brace et al. 1991:37).

If Huxley was wrong in his assumption that the African brain is significantly smaller than the European brain, he was quite correct in his recognition of the fact that Europeans have smaller jaws and teeth. Oddly enough, that "fact" had not been demonstrated by any systematic quantitative study before he produced his declaration, and very little attention has been devoted to the matter since that time. As it happens, the issue of tooth-size differences between human populations past and present has been largely ignored by the dental and anthropological sciences.

No living human population has teeth that are as large on the average as their predecessors in the Middle Pleistocene, so it is evident that dental reduction has taken place over the last 100,000 years or more in the lines that have led to all of the regional human inhabitants of the world. Reduction has amounted to at least 40-45% in those who live in the north temperate zone between Europe and the Middle East. This is the maximum amount of dental reduction visible in modern Homo sapiens, although it is equaled in spots in eastern Asia such as Hong Kong and the northern island of Hokkaido in Japan. The least amount of reduction is evident in Australia where it runs between 10 to 15% (Brace 1980). In sub-Saharan Africa, the amount of reduction in the groups in the Congo Basin and in West Africa with the largest jaws and teeth is around 25%, but it runs up to 40% in the Horn of East Africa.

The documented reductions in the dentition have all taken place as "archaic" human form — what I would call regional representatives of the Neanderthal Stage — becomes transformed into "modern" Homo sapiens (Brace l991b:170, 1994). We are not accustomed to thinking of the Neanderthals as cultural innovators, but the very real possibility exists that they may have been "the ones who pioneered the use of cooking as a regular means of preparing food" (Brace l991b:155). Survival in the north during the onset of glacial conditions depended on the control of fire. Among other things, there would have been no point in going to the trouble of bringing down a large Pleistocene prey animal if the thing would become unusable within a day or so by virtue of having frozen solid. "Obligatory cooking" (Brace 1994a,b), then, was a part of the cultural traditions of those who survived through the last two glacial maxima along the northwestern edge of human habitation in the Old World, and it has been suggested that the extensive hearth residues that characterized the Mousterian sites occupied by the Neanderthals were actually the remains of earth ovens in which they regularly thawed the products of the chase simply in order to make them edible (Brace and Montagu 1977:335-336; Brace 1978:214, 1979:545-546, 1992:16-17; Brace et al. 1987:713-714, 1991:46-51).

Cooking not only made it possible to eat what previously had been frozen, but it reduced the amount of chewing necessary to get anything so treated into swallowable consistency. The regular use of cooking, then, reduced the amount of mandatory chewing. A reduction in the amount of tooth use over a lifetime meant that teeth did not wear out quite so fast, and also that a person did not need quite such a large dentition to be able to survive for the otherwise expectable human span. Under such conditions, mutations affecting tooth size could accumulate without being automatically weeded out by selection, and, since most such mutations produce a reduction in size, the predictable long-term results would be dental diminution. Today, the largest number of the people with the smallest teeth in the world are those who live in that stretch that runs from the Middle East through to the Atlantic Coast of Western Europe — just that area where the cooking of food has been in continuous use for the longest period of time.

Figure 4 shows a crude picture of relative tooth size among the modern populations of the Old World. The reader will remember that it was in just that stretch running from the Middle East to the west and north that pigment reduction began earliest and has gone to its greatest extent. Pigment, however, is related to the intensity of ultraviolet radiation, and teeth are only related to the nature of the tasks required to process food. Of course, food is more likely to freeze in areas of limited solar radiation, so there is a degree to which the value of maintaining skin pigmentation and the value of maintaining a dentition that could cope with uncooked food covary to a certain extent. Some of this is apparent when Figure 4 is compared with Figure 3, but it is also apparent that there are areas where the traits are completely uncorrelated.

The evident value of cooking at northern latitudes meant that it spread into the northeastern areas more readily than it did to the south. Dental reduction then followed suit, and tooth size in Eastern Asia followed the same track that it had taken starting somewhat earlier in the northwestern parts of the Old World. Eventually, of course, it spread south because, although it was not necessary to thaw food in the tropics, the repeated application of heat to the ripening results of a previous kill could partially delay and counteract the noxious effects of the various micro-organisms that would otherwise render the decaying products of earlier hunting activities unfit for human consumption.

Cooking was adopted last in Australia, and dental reduction is least evident among the aborigines who were encountered by the Europeans who settled there over the last two centuries. Earth oven cookery had spread to Australia perhaps before the end of the Pleistocene, but, in any case, the kind of reduction in chewing stress that it represented got into Australia later than anywhere else in the world. Not only that, but it spread slowly south in the continent and never did get to Tasmania before the terminal Pleistocene rise in sea level turned it into an island. As a consequence, there is a tooth-size gradient in Australia running from the north down to the south where people had the largest-sized teeth of any living human beings. Even so, tooth size had begun to reduce from the Middle Pleistocene-sized levels that were displayed only 10,000 years ago (Br