Race

I

Introduction

Race, term historically used to describe a human population distinguishable from others based on shared biological traits. All living human beings belong to one species, Homo sapiens. The concept of race stems from the idea that the human species can be naturally subdivided into biologically distinct groups. In practice, however, scientists have found it impossible to separate humans into clearly defined races. Most scientists today reject the concept of biological race and instead see human biological variation as falling along a continuum. Nevertheless, race persists as a powerful social and cultural concept used to categorize people based on perceived differences in physical appearance and behavior.

Interest in defining races came from the recognition of easily visible differences among human groups. Around the world, human populations differ in their skin color, eye color and shape, hair color and texture, body shape, stature, limb proportions, and other physical characteristics. However, most anthropologists and biologists regard these differences between populations as largely superficial, resulting from adaptations to local climatic conditions during the most recent period of human evolution. Genetic analysis, which provides a deeper and more reliable measure of biological differences between people, reveals that overall, people are remarkably similar in their genetic makeup. Of the genetic differences that do exist, more variation occurs within so-called racial groups than between them. That is, two people from the same “race” are, on average, almost as biologically different from each other as any two people in the world chosen at random. This high degree of genetic diversity exists within populations because individuals from different populations have always intermingled and mated with each other. Given that populations have interbred for most of human history, most anthropologists reject the idea that “pure” races existed at some time in the distant past. Today, genetic analysis has replaced earlier methods of comparing color, shape, and size to establish degrees of relationship or common ancestry among human populations.

The term race is often misunderstood and misused. It is often confused with ethnicity, an ambiguous term that refers mostly, though not exclusively, to cultural (non-biological) differences between groups. An ethnic group derives its identity from its distinctive customs, language, ancestry, place of origin, or style of dress. For example, the Hispanic ethnic group comprises people who trace their ancestry to Spanish-speaking countries in the Western Hemisphere. Although some people assume Hispanics have a common genetic heritage, in reality they share only a language. Members of an ethnic group with a common geographic origin often do share similar physical features. But people of the same ethnic group may also have very different physical appearances, and conversely, people of different ethnic groups may look quite similar. People may also mistakenly use the term race to refer to a religion, culture, or nationality—as in the “Jewish race” or the “Italian race”—whose members may or may not share a common ancestry. The term race is also sometimes used to refer to the entire human species, as in the “human race.” In everyday language, the distinction between race and ethnicity has become blurred, and many people use the terms to mean the same thing.

Many people believe, falsely, that differences in physical appearance have something to do with differences in the behavior, attitude, intelligence, or intrinsic worth of people. These beliefs promote racism, prejudice or animosity against people perceived to belong to other races. At its worst, racism has inspired the abuse and extermination of enormous numbers of people. Recent historical examples included the near-extermination of Native Americans by European settlers of the Americas between the 16th and 20th centuries, the capture and export of Africans for use as slaves in the Americas from the early 17th to the mid-19th century, the extermination of Jews in Europe by German Nazis during World War II (1939-1945), and the system of apartheid perpetrated by Afrikaners against all nonwhite peoples in South Africa.

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This article examines the concept of human races and explains why most scientists have discredited race as a biological concept. It also traces the history of attempts to classify people into races, from ancient times to the present. Finally, the article describes the principles of human biological variation and discusses race as a sociological concept.

II

Problems in Defining Races

Around the world, human populations differ in their skin color, eye color and shape, hair color and texture, body shape, height, limb proportions, nose and lip size and shape, and other physical characteristics. For example, peoples of the Arctic, such as the Inuit, differ significantly in body form and skin color from Aboriginal Australians. Likewise, Norwegians appear quite different from Nigerians in their skin color and hair color and texture. These easily visible differences between peoples led early scientists to attempt to define races based on outward physical appearance. Such observable traits make up a person’s phenotype. In more recent times, scientists have tried to define races based on genotype, the genetic makeup of individuals. Both methods have shortcomings that illustrate the fundamental problems of racial classification.

A

Based on Physical Appearance

Interest in classifying races flourished in the 19th century and continued in the 20th century. But every anthropologist proposed a different list of races, with numbers varying from as few as 2 to as many as 60 or more. Racial taxonomists usually divided into two opposing camps: “lumpers,” who minimized the number of races; and “splitters,” who divided humans into many small, local races. Early racial classification schemes were based primarily on skin color. For example, many scholars once believed all people could be classified into one of three main races: (1) Caucasoid, or “white”; (2) Negroid, or “black”; and (3) Mongoloid, or “yellow.” These races corresponded roughly to the geographic areas of Europe, sub-Saharan Africa, and Asia, respectively.

However, some people did not fit neatly into any of these races. For example, the Aboriginal people of Australia have dark skin similar to tropical Africans. But some Aboriginal people have blond hair, unlike most Africans. Were they Negroid or Caucasoid? Some scholars added a new race, Australian, to avoid the problem. The peoples of southern India and Sri Lanka, who have dark skin like tropical Africans but facial features and hair like Europeans, posed a similar classification problem. Again, some scientists added an Indian race. One trait thought to be unique to Mongoloids was the epicanthic fold, a fold of skin across the inner part of the eye. But anthropologists soon discovered that certain African and Native American groups also have epicanthic folds. Should they also be classified as Mongoloid?

These examples show the difficulty in classifying races based primarily on a single physical trait: Populations that share the trait are subjectively lumped into the same race, without any scientific evidence that they are more closely related to each other than to other groups. In addition, the choice of trait is completely arbitrary. One could just as logically choose to classify races by nose shape as by skin color.

An alternative approach might classify races on the basis of particular combinations or clusters of external traits, rather than a single trait. But this approach reveals other problems. Traits that may seem uniform within a population actually vary widely between individuals, making it difficult to classify individuals into racial groups. Furthermore, physical traits are inherited independently of one another. For example, stature in a population may vary from very small to very tall and shows no relation to skin color. Each trait has a unique pattern of geographic distribution that may be unrelated to those of other traits.

Perhaps the greatest problem in racial classification involves determining the boundaries of the races. Populations from different continents or climates may differ profoundly in physical appearance, suggesting that the differences between peoples are sharp and discrete. But scientists now recognize that most human physical characteristics vary gradually and smoothly over large geographic areas. Anthropologists refer to this gradient of variation as a cline. For example, skin color is distributed as a cline, generally varying along a north-south line. Skin color is lightest in northern Europeans, especially in those who live around the Baltic Sea, and becomes gradually darker as one moves toward southern Europe, the Mediterranean, the Middle East, and into northern Africa and northern subtropical Africa. Skin is darkest in people who live in the tropical regions of Africa. The lack of clear-cut discontinuities makes any racial boundary based on skin color totally arbitrary. Similar continuity exists for most other physical traits. (For more information about skin color as an environmental adaptation, see the Variation and Environmental Adaptation section of this article.)

Racial classification has generally relied on the premise that each race can be defined by a certain set of physical features that are inherited and unchangeable. But scientists now know that a population’s phenotype (visible physical characteristics) can change without genetic change. For example, the average height of adult males in Japan increased an estimated 10 cm (4 in) in the span of only a few decades after 1950. This time span is too short to permit major genetic changes; changes in the Japanese diet account for the height increase. Given how rapidly some phenotypic traits can change in response to environmental conditions, they form a poor basis for defining fixed, biological races.

Race mixing highlights another problem in defining races. In the United States, the child of a white parent and a black parent is usually defined as black, because American society traditionally has not recognized intermediate racial categories. In biological terms, however, the child shares in each parent’s genetic heritage equally. Until the mid-20th century, many states defined a person as black if he or she had even a small fraction of black ancestry. Most state laws specified the fraction of black ancestry that made someone black as one-fourth or one-eighth. Thus, having one black great-grandparent was sufficient to define a person as black, but having seven white great-grandparents was insufficient to define the person as white. A Virginia law (overturned in 1967) went even further, defining as black “every person in whom there is ascertainable any Negro blood”—the so-called one-drop rule. These definitions were created as part of laws against miscegenation, which were designed to prohibit interracial marriage. Anthropologists today recognize that race is also culturally relative. A light-skinned African American considered black in the United States would be considered white by many dark-skinned populations of Africa. These examples show that race is socially and culturally constructed, not determined by biology.

A final argument against basing races on phenotype is that relatively few genes determine surface characteristics, such as skin color, hair color, and facial features. For example, fewer than ten genes determine skin color. Considered against the estimated 30,000 genes that make up the entire human genome (the total of all human genes), skin color and other external features represent a trivial source of biological variation. There are many other sources of human biological variation that we cannot see, such as variations in blood type and susceptibility to certain diseases. It is of course inevitable to be influenced by what we see, and this helps to explain why people attribute so much more importance to visible physical traits.

B

Based on Genetic Makeup

As scientists in the 20th century became aware of the many problems in defining races based on physical appearance, some turned to the field of genetics in an effort to define races more scientifically. Genetic analysis allows scientists to learn about differences between people at the level of the genotype—the structure of the molecular genetic material, deoxyribonucleic acid (DNA). Genes are segments of DNA that determine the inheritance of certain traits, or groups of traits. Genetic research provides much more consistent and verifiable information about human variation than do phenotypic studies, primarily because genes are much less susceptible to rapid changes produced by the environment. In addition, genetic studies can examine a much wider range of variable traits—including those not visible to the naked eye.

Scientists first learned about the human genotype through research on proteins—substances fundamental to the function and structure of the body. Proteins indirectly provide information about gene structure because they are the main product of genes. The human body contains tens of thousands of different proteins, most of which vary in form from person to person. Protein research has focused on variation in blood groups, hemoglobin (the protein that carries oxygen in red blood cells), red blood cell enzymes, blood-serum proteins, and human lymphocyte antigens (HLA) that affect individuals’ resistance to organ transplants.

The first attempts to classify races by genetic traits used the ABO system of blood groups. Blood groups determine whether any two people can successfully exchange blood through medical transfusion. All people belong to one of four blood groups (A, B, AB, or O), depending on which alleles (forms) of the ABO gene they inherited. The three major alleles of this gene, A, B, and O, are present in almost all populations of the world, but in different proportions. For example, the O allele reaches its maximum frequency among Native Americans, so much so that in South America almost all individuals have type O blood. In central Canada, type A blood is unusually frequent, type O somewhat less frequent, and types B and AB are rare or absent. On other continents one finds all blood groups, with some local variation. But the ABO blood group system lends itself very poorly as a way to distinguish races. Two populations that are remote both geographically and biologically (based on almost all other criteria), such as Germans and New Guineans, often show very similar ABO allele frequencies.

When scientists examine a large number of different genes, some distinctions between groups begin to appear more clearly. For example, one can usually find some degree of genetic differentiation between populations separated by geographic barriers, such as seas, mountains, and rivers. This occurs because geographic barriers tend to isolate populations from each other, although no barrier seems to completely prevent interbreeding of populations. The genetic differentiation observed between such populations is always extremely modest and not discernible without a thorough analysis. In most areas of the world, genetic traits, like phenotypic (external) traits, are distributed clinally—that is, they vary in a smooth, gradual pattern across geographic areas. For example, in Central Asia the transition from a European type to an East Asian type (as defined by gene frequencies) is almost continuous, making the task of drawing a boundary between “European” and “Asian” races impossible. Around the world, abrupt changes in gene frequencies are unusual between neighboring populations. The reason is that human groups, throughout history, have generally mixed and mated with one other, guaranteeing a constant flow of genes between populations.

By analyzing the data from a sufficiently large number of genes, one could identify hundreds of thousands of local populations at a minimum, each with a slightly different profile of gene frequencies. But this analysis would not answer the question of how many basic races there are. No reasonable multiplication of the list of races could cope with the observed continuity and complexity of genetic variation. Thus, most scientists have given up racial classification as a futile exercise.

The direct analysis of DNA, which became possible in the 1980s, has revolutionized the study of human variation. DNA research has shown that similarities among all people far outweigh any differences. On average, two randomly chosen individuals have 99.9 percent of their genetic material in common. Of the 0.1 percent variation that does exist, 85 percent exists within populations; only 15 percent exists between populations. In other words, almost all the genetic differences between any two people are due simply to the fact that they are different individuals. In comparison with the genetic variation observed among individuals, that between human groups, however defined, is almost negligible.

The human species has less genetic variability than many other animal species, including chimpanzees, the closest living relatives of humans. The reason is that the differentiation among humans living today probably began in the recent evolutionary past. Genetic studies suggest that all people alive today are descended from a relatively small group of humans in eastern Africa who began migrating out of Africa as recently as 50,000 years ago. For more information, see the Human Origins section of this article.

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