FBI identifies fugitives by photographs, physical features, occupation, nationality, and race. From left to right, the FBI identifies the above as belonging to the following races: White, Black, White (Hispanic), Asian. Top row males, bottom row females.
The term race is used in a wide variety of contexts, with related but often distinct meanings. Its use is often controversial, largely because of the political and sociological implications of different definitions, but also because of disagreements over such issues as whether humans can be meaningfully divided into multiple races.
In biology, some people use race to mean a division within a species. Thus, in certain fields it is used as a synonym for subspecies or, in botany, variety. In the case of honeybees, for instance, it stands as a synonym for subspecies. In this usage, race serves to group members of a species that have, for a period of time, become geographically or genetically isolated from other members of that species, and as a result have diverged genetically and developed certain shared characteristics that differentiate them from the others. Although these characteristics rarely appear in all members of the group, they are more marked in or appear more frequently than in the others.
The analyses of most social scientists conclude that the common social notions of race are social constructs. These defintions of race are derived from custom, vary between cultures, and are described as imprecise and fluid. Often these definitions rely on phenotypic characteristics or inferred ancestry. The analysis of human genetic variation also provides insight into human population history and structure. The recent spread of humans from Africa has created a situation where the majority of human genetic variation is found within each human population. However, as a result of physical and cultural isolation of human groups, a significant subset of genetic variation is found between human groups. This variation is highly structured and therefore useful for distingushing groups and placing individual into groups. Admixture and clinal variation between groups can be confounding to this kind of analysis of human variation. The relationship between social and genetic definitions of race is complex. Phenotypic racial classifications do not necessarily correspond with genotypical groups; some more than others. To the extent that ancestry corresponds to social definitions of race, groups identified by genetics will also correspond with these notions. Whether human population structure warrants the distinction of human 'races' is a matter of debate, with majority opinions varying between disciplines. Some biologists prefer the term population to race. Similar reasoning has lead some to describe races as (inbred) extended families.
The remainder of this article reviews debates over the scientific validity of the concept of race in human beings; the historical construction, social functions, and cultural meanings of racial schemata; and the ethics and politics of the term.
Some people believe that certain characteristics of the species Homo sapiens justify classification of humans into various races. Such characteristics include physical characteristics, culture, geography, religion, language, nationality, etc., but do not include contingent factors such as a common history of disease. The practice of dividing humans into races emerged during the Enlightenment as a way of justifying the enslavement and oppression of others who were deemed to be of "inferior" non-white races, and therefore supposedly best fitted for lives of toil under white supervision; to the extent that it made the distance between races seem nearly as broad and insurmountable as that between species, it helped ease unsettling questions about the appropriateness of treating other human beings as if they were mere pack animals. The practice was at that time generally accepted by both the scientific and lay communities.
In the early-to-mid 20th century, many scientists began questioning previously accepted causal relationships between biological and cultural attributes. Some scientists also began questioning the taxonomic validity of race attribution, especially in the decades immediately after the Second World War (in the course of which racialist theories served to justify enormous genocidal crimes; see eugenics and the Holocaust). This questioning gained particular momentum in the 1960s, in the context of the U.S. civil-rights struggle and the emergence of numerous anti-colonial movements worldwide. As new data began to emerge in the 1960s indicating that most human genetic variation was actually within races rather than between them, many scientists came to reject the concept of race as a biological fact altogether, at least as it applies to humans. Nevertheless, the belief that human races exist remains almost universal amongst lay audiences, and like any belief held by a large number of people, is significant in itself regardless of its scientific validity. The concept of race continues to impact people through its effects on social behaviour (see communal reinforcement).
In biology, a race was defined as a recognisable group forming all or part of a monotypic or polytypic species. A monotypic species has no races (this can also be expressed: "a monotypic species has only one race"). Monotypic species can occur in several ways:
A polytypic species thus has two or more races (or, in current parlance, two or more "sub-types"). These are separate groups that are clearly distinct from one another and do not generally interbreed (although there may be a relatively narrow hybridization zone), but which would interbreed freely if given the chance to do so. Note that groups which would not interbreed freely, even if brought together such that they had the opportunity to do so, are not races: they are separate species.
Humans clearly vary considerably – enough to have made early scientists accept the correctness of Carolus Linnaeus' view that humans should be divided into several sub-species. By far the greater part of human genetic variation, however, occurs within "racial" groups and the variation between racial groups accounts for between 5-7% of the total.² Nevertheless, although the difference between races is less than 10% of the difference within any particular race, this does not in itself invalidate the suggestion that there might be different races of Homo sapiens sapiens. Indeed, the genetic variation between races is highly structured, so that when many points of variation are considered it is possible to distinguish groups and allocate individuals into groups. Moreover, the rules of biological classification do not set any 'smallest allowable difference' between taxa: any distinct difference is sufficient.
However, a distinct difference is only one of the two conditions that must be satisfied before a different form can be classified as a sub-species or even a race; the second is the lack of significant gene flow between populations. In the case of human "races", although there has historically been little or no direct gene flow between distantly separated populations such as the aboriginal Australians and black Africans, it is nonetheless incorrect to assume that there has been little gene flow between the various races, as all that is required for it to occur is that locally adjacent populations interbreed, as has typically been the case. In fact, enough such gene flow has occurred throughout human history that the most recent common ancestor of all humans alive today has been estimated as living as recently as 3,500 years ago  (http://www.sciencedaily.com/releases/2004/09/040930122428.htm), although this does not necessarily constitute significant gene flow.
In recent centuries there has been a dramatic increase in the amount of gene-flow occurring even between geographically very distant human populations. People began engaging in intercontinentel travel on an ever more regular basis, and today such travel is widespread. As such, interbreeding between previously separated peoples is now not only possible but widespread. Given this change, the lines between races are fading, and have perhaps already been totally removed in some regions, particularly in Latin America and parts of Southern Africa.
Given the way that different human races fade gradually from one to another in many parts of the world, the overwhelming majority of the current generation of cultural anthropologists draw the conclusion that human racial variation is in fact clinal, and that the human species is monotypic. However, this is also true for differences between sub-species, and even species, in other animal populations. Generally, an amount of change sufficient to label two different animal populations as different sub-species is often no longer considered enough to label two different human populations as being of different races.
Of course, the delicacy of this definition has left the issue much in debate, especially among physical anthropologists, for if "clines" lead to large areas of separate near-homogeneity, as they seem to do in places like Kenya, Sweden and China, then the people in these areas seem marked off by delimiters resembling nothing so much as the traditional physiological touchstones of "race". A counter-argument is that what often seems to the naked eye to be a "near-homogenous" population is often nothing of the sort, and indeed, recent evidence indicates that genetic variation occurs in a smoothly gradient fashion even in such regions, with the apparent gaps previously noted turning out to have been merely artifacts of sampling techniques that implicitly presumed the existence of near-homogenous and genetically distinct populations.
Scientists who maintain race as an important biological concept point out that in determining overall relatedness the entire genetic cohorts of groups must be compared, and that when this is done, it is possible to recover the traditional racial groupings, provided one uses enough of the right markers. The caveat to this finding is that one must decide how finely one chooses to distinguish between groups, such that one can determine two "races" (Africans vs. non-Africans), three, four or more. Thus, the number of races discovered by these methods will be arbitrary. Moreover, some of the groups which emerge as "races" under closer scrutiny would hardly be recognized as such in the conventional sense. It is important to keep in mind that it is not necessarily the case that any two given individuals of the same race will be genetically closer than will two people of different races.
Some biologists believe that the tendency to view races as a social construct, or as not biologically significant, is incorrect, and is influenced not by science but by racial politics and political correctness. They claim that researchers on racial differences are often attacked as racists, even if said researchers espouse liberal sociopolitical views and claim to be against racism. A number of books and articles in recent years attempt to rebut what the authors see as biased science. Vincent Sarich and Frank Miele, in Race: The Reality of Human Differences, claim that "racial differences in humans exceed the differences that separate subspecies or even species in such other primates as gorillas and chimpanzees" and hold that "race is a biologically real phenomenon with important consequences". A number of scientists have supported this currently controversial view, including Ralph L. Holloway, Professor of Anthropology, Columbia University; Arthur Jensen, University of California-Berkeley; Joseph Carroll, University of Missouri-St. Louis; and Thomas J. Bouchard, Jr., Prof. of Psychology, University of Minnesota.
Historians, anthropologists and social scientists today are apt to describe the notion of race as it applies to human beings as a "social construct", preferring instead to use the concept of "population," which can be given a clear operational definition. The concept of biological race, however, has proved resilient and is still used in day-to-day speech even among those who, when questioned, reject the formal existence of race. This may be a matter of semantics, in that such scientists and laypeople use the word race to mean population, or it may be an effect of the underlying cultural power of the concept of race in racist societies. Whether it be race, population, or some other appellation, a working concept of sub-specific clustering can still be useful, because in the absence of cheap and widespread genetic tests, various gene mutations that have been historically strongly linked to membership of certain human subgroups (see Cystic fibrosis, Lactose intolerance, Tay-Sachs Disease and Sickle cell anemia) are difficult to address without recourse to a category higher than "individual" and lower than "species". Nonetheless, as direct genetic tests for various conditions become ever cheaper, and as detailed haplotype maps and SNP databases become available, there should be an ever-diminishing need to seek recourse in race as a stand-in for the desired information. This is just as well, as the current rate of heightened inter-group mating is steadily reducing the predictive power of race; a telling statistic is that, stereotypes notwithstanding, an overwhelming percentage of babies born with Tay-Sachs in North America nowadays are not from families identifying themselves as Jewish.
History of the term
The historical definition of race, before the development of evolutionary biology, was that of common lineage, a vague concept interchangeable with species, breed, cultural origin, or national character ("The whole race of mankind." – Shakespeare; "From whence the race of Alban fathers come" – Dryden).
The word race, interpreted to mean common descent, was introduced into English in about 1580, from the Old French "rasse" (1512), from Italian razza, which may have been derived from the Latin word generatio (a begetting).
This late origin for the English and French terms is consistent with the thesis that the concept of "race" as defining a very small number of groups of human beings based on lineage dates from the time of Columbus. Older concepts that were also at least partly based on common descent, such as nation and tribe, entail a much larger number of groupings.
The first published classification of humans into distinct races seems to have been François Bernier's (1620–1688) Nouvelle division de la terre par les différents espèces ou races qui l'habitent ("New division of Earth by the different species or races which inhabit it"), published in 1684. Bernier (1625–1688) distinguished four "races":
The 19th century concept of race was based primarily on morphological and cosmetic characteristics such as skin color, facial type, cranial profile and amount, texture and color of hair. Though such characteristics have since been declared by many experts to have a minimal relationship with any other heritable characteristics, they retain some persuasive force because it is easy to immediately distinguish people based on physical appearance.
Because people of different races can interbreed, this method of classification is "weak" in the sense that it can be difficult to determine to which categories some borderline individuals belong. (Contrast the difficulty of determining to which group a child of mixed parentage belongs with the much more clear-cut decisions involved in determining membership in species). In other words, racial purity does not have a clear biological meaning. On the other hand, it is clear that for an extended period of time after Homo sapiens' first migrations from Africa (probably around 80,000 BCE) and before the rise of wheeled and seagoing transportation (around 3,000 BCE), geographically isolated groups of people underwent some degree of divergent evolution. Whether that degree was high enough to merit strict taxa beneath the species level is the primary question that has roiled the generations of human biologists since the 1800s. It is a complicated issue full of semantic and emotional pitfalls, with much at stake on the consensus, for educators, physicians, political officeholders, judges, law enforcement officers and many others look upon scientific findings as the bedrock authority for their curricula, diagnostic methods, budget expenditures, case law and criminal suspect profiling.
Among the 19th-century naturalists who defined the field were Georges Cuvier, James Cowles Pritchard, Louis Agassiz, Charles Pickering (Races of Man and Their Geographical Distribution, 1848), and Johann Friedrich Blumenbach. Cuvier enumerated three races, Pritchard seven, Agassiz eight, and Pickering eleven. Blumenbach's classification was widely adopted:
Researchers in the decades following Blumenbach classified the Malay and American races as branches of the Mongolian, leaving only the Caucasian, Mongolian, and Ethiopian races. Further explication in the early and mid twentieth century, notably by American anthropologist Carleton S. Coon, arrived at three primary races (Negroid, Caucasoid, Sinoid) with a small number of less widespread races (especially "Australoid").
In Blumenbach's day, physical characteristics like skin color, cranial profile, etc., went hand in hand with declarations of group moral character, intellectual capacity, and other aptitudes. The "fairness" and relatively high brows of "Caucasians" were held to be apt physical expressions of a loftier mentality and a more generous spirit. The epicanthic folds around the eyes of "Mongolians" and their slightly sallow outer epidermal layer bespoke their supposedly crafty, literal-minded nature. The dark skin and relatively sloping craniums of "Ethiopians" were taken as wholesale proof of a closer genetic proximity to the other great apes, despite the fact that the skin of chimpanzees and gorillas beneath the hair is whiter than the average "Caucasian" skin, in the face of the reality that the thin lips characteristic of "Caucasians" are actually shared by all the other hominids, despite the fact that sloping foreheads are about as common amongst Englishman and Germans as amongst "Ethiopians" (with "primitive" brow ridges even more common amongst "Caucasians"), and even though the straight and relatively profuse body hair of Europeans is most akin to the original hominid condition. By Coon's day, group physical characteristics were, for the most part, unhitched from assessments of group character and aptitude.
Modern criticism of the biological significance of race can be dated to the publication in 1935 of a book by Julian Huxley and A.C. Haddon: We Europeans: a survey of "racial" problems (London: Jonathan Cape, 1935).
In everyday speech, race is often used to describe populations that are better defined as ethnic groups. This often leads to discrepancies between "scientific" views on race and popular usage to the term. For instance in many parts of the United States, categories such as Hispanic or Latino are used to define race in much the same way as terms such as white and black have been traditionally used, though Hispanics constitute a linguistic and cultural grouping that may come from a wide variety of backgrounds. It is also true that in the United States, thanks to the one-drop rule, the term "black" subsumes people with an extremely broad range of features and ancestry under a single label, even though many of those who are termed "black" would be more accurately described as "white" under any objective terminology. In much of Europe groups such as Roma, Turks, and Arabs are commonly defined as racially distinct from "white" Europeans, though all of these groups are considered to be "Caucasian" in traditional physical anthropology.
Politics of race
The concept of race was applied at the time of Blumenbach by political theorists such as Johann Gottfried von Herder to nationalist theory in order to develop a militant ethnic nationalism. They posited the historical existence of "races" such as the German and French race, branching from basal races supposed to have existed for millennia, such as the "Aryan" race, and believed political boundaries should mirror these racial boundaries. Later, one of Hitler's favorite sayings was "Politics is applied biology". Hitler's ideas of racial purity led to atrocities on an unprecedented scale, and "racial cleansing" or "ethnic cleansing" as a sociopolitical motivation or justification has reared its head several times since Hitler (particularly in Cambodia, the Balkans and East Africa). In one sense, such "cleansing" is merely another name for the tribal warfare and mass murder that has afflicted human society from time out of mind. But these crimes seem to gain an extra intensity and thoroughness when the perpetrators believe their acts are sanctioned on scientific grounds.
Inequalities based on presumed racial differences have been a concern of United States politicians and legislators since the country's founding. In the 19th century most "white" Americans (including abolitionists) explained racial inequality as an inevitable consequence of biological differences. In the second half of the 20th century, political and civic leaders as well as scientists debated whether racial inequality is biological or cultural in origin. On one end of the political spectrum, some argued that current inequalities between blacks and whites are primarily cultural and historical, the result of such historical wrongs as slavery and segregation, and could be redressed through such programs as "affirmative action" and "Head Start." On the other end of the spectrum, a movement to redirect tax money away from remedial programs for minority phenotypes was based on interpretations of aptitude test data which, according to advocates, showed that race-linked differences in basic ability are biological in origin and cannot be leveled even by intensive educational efforts. In electoral politics, many more members of racial and ethnic minorities have won important offices in western nations compared to earlier times, although the very highest offices tend to remain in the hands of racial/ethnic majorities.
Religious leaders active in the United States began to decry segregation and discrimination based on race in the latter half of the 20th century. The Rev. Dr. Martin Luther King famously requested people to form a society where people were judged "on the content of their character, not the color of their skin."
Anthropological and genetic studies of race
In the 19th century many natural scientists made three claims about race: first, that races are objective, naturally occurring things; second, that there is a strong relationship between biological races and other human phenomena (such as social behavior and culture, and by extension the relative material success of cultures); third, that race is therefore a valid scientific category that can be used to explain and predict individual and group behavior. In the 20th century, mainstream anthropologists and others rejected each of these claims, while continuing to study between-group genotypic and phenotypic variations. By the end of the 20th century, most social and many natural scientists turned to the "population" concept to talk about these variations, arguing that accounts of "race" (within both the popular and scientific literatures) are socially constructed. Some social and natural scientists, however, argue that new studies in molecular genetics support a nomenclature strongly reminiscent of traditional racial and ethnic terminology.
Since human beings are among the most complex entities we know of, and as ethical considerations preclude much of the kind of experimentation routinely carried out on other animals, the empirical study of man is in many ways the most difficult of all. It is no surprise that fields like anthropology, human genetics and psychology are in flux, and the state of these fields may change radically during this century as advances in the more elementary sciences are synthesized into increasingly objective definitions of "human nature". Recognition of sub-specific group traits may find a place in these definitions, probably without, however, the valuations of overall superiority and inferiority formerly attached to them.
A rejection of 19th century assumptions was initiated by Franz Boas, the founder of American academic anthropology. In the first decades of the 20th century he studied the relationship between race and height in New York City, discovering that the children of immigrants were taller than their parents. Although height is clearly primarily a biological phenomenon, he concluded that an individual's height was determined not only by inheritance but by environment as well (in this case, better pre- and neo-natal care, especially nutrition). Boas's conclusion has been confirmed many times since, for example by the remarkable gain in the average height of Japanese people since the dietary changes that followed the end of World War II. But it was counter-intuitive, because in typical populations under relatively stable environmental conditions, about 80% of the variation in individual height is due to genetic variations, and at any point in time, human subgroups tend to have different average heights. As a result, many of Boas's students continued to accept the existence of race as a biological fact. But they concluded that there was no relationship between biological race and other human phenomena (such as social behavior, culture, intelligence and morality).
By the 1950s most anthropologists had come to question the very existence of race as a biological phenomenon. This rejection was based on three facts. First, they pointed out that the preponderance of evidence suggests that all human beings are descended from a common ancestor (although this fact alone has little bearing on the subsequent formation or non-formation of new subgroups). Second, they observed that there are many biological differences between people that are not taken into account by race (for example, blood type). Finally, they pointed out that oftentimes the genetic differences between members of the same race are greater than the average genetic difference between races. For example, the variation in blood types within specific groups is 85%, but the total variation between groups is only 15% (see the American Anthropological Association's Statement on Race  (http://www.aaanet.org/stmts/racepp.htm)).
These developments had important consequences. For example, some scientists developed the notion of "population" to take the place of race. This substitution is not simply a matter of exchanging one word for another. Populations are, in a sense, simply statistical clusters that emerge from the choice of variables of interest; there is no preferred set of variables.
The "populationist" view does not deny that there are physical differences among peoples; it simply claims that the historical conceptions of "race" are not particularly useful in accounting for these differences scientifically. In particular, populationists claim that:
Since the 1960s, some anthropologists and teachers of anthropology have re-conceived "race" as a cultural category or social construct, in other words, as a particular way that some people have of talking about themselves and others. As such it cannot be a useful analytical concept; rather, the use of the term "race" itself must be analyzed. Moreover, they argue that biology will not explain why or how people use the idea of race: history and social relationships will.
Other anthropologists and human geneticists argue that race is indeed a valid and valuable concept and that those holding the opposite view allow their social consciences (laudable per se) to confuse and delay accurate interpretations and applications of empirical data. They are not convinced by the substitution of the term population for the term race, because it leads to a potentially harmful imprecision in communication (for example, when one could simply say "caucasian" one is instead compelled to say something like "an individual of the western Eurasian population", and when that individual doesn't happen to currently reside in western Eurasia one must say "an individual whose ancestors were of the western Eurasian population"). Recent studies by population genetics researchers indicate that the small portion of human genetic which occurs along the the traditional conceptual lines of race does so in a clinal fashion, which is to say that it can be mapped out along smoothly varying gradients in a manner analogous to that used employed in topographical maps. At no location in the world is there a sharp genetic discontinuity between races, and the use of racial markers in medical genetics is only justifiable where the various racial groups hail from regions that are geographically very distinct. This is still true for the most part in the United States, whose constituent population is drawn mostly from Western Europe, coastal West Africa and East Asia (though as intermarriage rates continue to increase, it cannot be expected to be indefinitely true), but it is extremely unlikely to hold in places like Russia, where racial variation occurs in a smooth continuum from west to east, in Latin America, where admixture is almost everywhere the norm, or in a Western Europe increasingly settled by people from the Middle East and North Africa. Racial DNA markers of the sort employed by American police officers are effective in that country largely because "whiteness" has historically been defined as the complete absence of black ancestry, not because the phenotypical distinctions between "white" and "black" looking Americans are so easily distinguished using genetics. In Brazil and Cuba, where interracial admixture has not been burdened by a "white" vs. "less than white" dichotomy, racial DNA markers are often utterly uninformative about a person's physical appearance.
Example: United States
In the United States in the 19th century, African-Americans, Native Americans, and European-Americans were each classified as different races. But the criteria for membership in these races were radically different. The government considered anyone with "one drop" of Black blood to be Black. In contrast, Indians were defined by a certain percentage of "Indian blood". And to be White one had to have "pure" White ancestry. These differing criteria for membership in particular races has little to do with biology and much to do with political relations between Blacks and Indians on the one hand, and Whites on the other.
By these criteria, it was very easy for a child to be categorized as Black. This likely reflects the requirements of the slave-economy of the U.S. South, for the vast majority of slaves were classified as Black. Even the child of an enslaved African woman and a White master was considered Black, or "of African descent." More importantly, such a child would be a slave. In comparison, it was harder for a child to be classified as Indian. After a few generations of inter-racial marriages, a child might not be considered Indian at all. This likely reflects the requirements of the U.S. economy during the period of westward expansion, although the greater outward similarity of "Whites" and "Indians" surely came into it. Indians had treaty rights to land, but if an individual with one Indian great-grandparent was no longer classified as Indian, they would lose special rights to land. At a time when Whites ruled both Blacks and Indians, it is no coincidence that the hardest race to prove membership in was White.
Even the so-called politically correct terms used in the United States of African-American, or Hispano-American keeps this logic, where descendancy is more important than skin color.
Compared to 19th century United States, 20th century Brazil was characterized by a relative absence of sharply defined racial groups. This pattern reflects a different history and different social relations. Basically, race in Brazil was biologized, but in a way that recognized the difference between ancestry (which determines genotype) and phenotypic differences. There, racial identity was not governed by a rigid descent rule. A Brazilian child was never automatically identified with the racial type of one or both parents, nor were there only two categories to chose from. Over a dozen racial categories would be recognized in conformity with the combinations of hair color, hair texture, eye color, and skin color. These types grade into each other like the colors of the spectrum and no one category stands significantly isolated from the rest. That is, race referred to appearance, not heredity.
One of the most striking consequences of the Brazilian system of racial identification was that parents and children and even brothers and sisters were frequently accepted as representatives of opposite racial types. In a fishing village in the state of Bahia an investigator showed 100 people pictures of three sisters and were asked to identify the races of each. In only six responses were the sisters identified by the same racial term. Fourteen responses used a different term for each sister. In another experiment nine portraits were shown to a hundred people. Forty different racial types were elicited. It was found, in addition, that a given Brazilian might be called by as many as thirteen different terms by other members of the community. These terms are spread out across practically the entire spectrum of theoretical racial types. A further consequence of the absence of a descent rule was that Brazilians apparently not only disagreed about the racial identity of specific individuals, but they also seemed to be in disagreement about the abstract meaning of the racial terms as defined by words and phrases. For example, 40% of a sample ranked moreno claro as a lighter type than mulato claro, while 60% reversed this order. A further note of confusion is that one person might employ different racial terms for another person over a short time. The use of term varies with the personal relationship and mood. The brazilian census admits one's race by the title the person gives to her or himself, and as a consequence hundreds of races appeared in the research, varying from blue (which is blacker than usual black) and green (which is whiter than usual white).
Consequently, people change their racial identity over their lifetimes. This is not the same as "passing" in the USA. It does not require secrecy and the agonizing withdrawal from friends and family that are necessary in the United States and among Indians of highland Latin America. In Brazil passing from one race to another occurs with changes in education and economic status. A light skinned person of low status is considered darker than a dark skinned person of high status.
So, although the identification of a person by race is far more fluid and flexible in Brazil than in the USA, there still are racial stereotypes and prejudices. African features were considered less desirable; blacks were considered inferior, and whites superior. These racist stereotypes are obvious relics of the slave-based plantation system. The complexity of racial classifications in Brazil is reflective of the extent of miscegenation in Brazilian society, which remains, highly, but not strictly, stratified along color lines.
Race and intelligence
Main article: Race and intelligence
Some researchers have proposed and studied possible relationships between race and intelligence. They argue that the average intelligence of racial populations differ. Such proposals have a long history, but many contemporary experts argue that they have always been wrong; see the American Anthropological Association's Statement on Race and Intelligence (http://new.aaanet.org/stmts/race.htm). One of the best known dissents to this opinion can be found in the works of Arthur Jensen, a controversial Professor of Educational Psychology at the University of California, Berkeley. Jensen claims his primary research in the field has found a high heritability of "the intelligence factor" with statistically significant genotype-based variation between populations. In 1974, an English biologist named John Randal Baker presented a lengthy argument in favor of innate racial differences in intelligence in a massive volume titled "Race" (Oxford University Press,1974), in which he claimed that there had been a systematic, politically-motivated suppression of classical biological anthropology outside Germany since the 1930s, and went on to attempt to demonstrate a relation between five historical civilizations (Sumerian, Egyptian, Indus valley, Helladic-Minoan and Sinic) and the supposed biological dispositions of their creators. Many arguments against the sorts of claims made by the likes of Jensen and Baker have also been made, perhaps the best known of which was presented in The Mismeasure of Man by Stephen Jay Gould, Professor of Zoology at Harvard University.
Although Gould's counter-arguments are themselves controversial, there are others which are far less so; a powerful and still valid criticism of the claims made by Jensen and his followers is that in drawing the conclusions they do, they confuse the meaning of the term heritability, which has a technical meaning in genetics whose implications often run counter to our intuitions. In particular, Jensen and company not only try to draw conclusions about between-group heritability from studies on within-group heritability, but they also assume that heritability is a fixed quantity even for one group, and to round it all off, they draw the conclusion that a trait with a high heritability will be relatively unresponsive to intervention; in fact, none of these inferences are valid.
For instance, height is estimated in most populations to have a heritability of 0.9, which is about as extreme as a trait which varies within a population can get, and yet it has risen dramatically in most populations across the globe in the space of a few generations; all its high heritability tells us is that if people within a particular group have children, the rank ordering of the heights of their children will be extremely similar to that of the parents, not that height could not increase in the space of a generation by as much as a foot or more. In the same vein, given any particular group of individuals, the more similar their environments, the higher the heritability of a particular trait will be, as heritability is defined simply as the ratio of genetic to environmental variation; this is why it is invalid to attempt to generalize from heritability studies on white middle-class Americans to draw conclusions about the "innate" capabilities of white and black people, when the latter group not only have many cultural traits which set them off from the white majority, but are also disproportionately encumbered by material hardships of all kinds maybe partly being a result of their supposed incapability.
phylogenetic tree like this one is usually derived from DNA or protein sequences from human populations. Indivduals from the various continental groups tend to be more similar to one another than to people from other continents. The tree is rooted in the common ancestor of chimps and humans, which is believed to have originated in Africa. Note: vertical distances are not meaningful; double dashed lines indicate segments that are not to scale.
Some people define their ideas of race in terms of the genetic similarities of groups of individuals that have formed when the human species migrated across the globe and subsequently adapted to new environments or was otherwise changed genetically.
Recent genetic analyses have enabled the concept of race to be represented in somewhat cladistic terms. These studies have indicated that, as already known, Africa was the ancestral source of all people. Australian aborigines were found to be an early out-group that remained isolated. All other groups, including Europians, Asians, and Native Americans, were found to be a single related (monophyletic) group resulting from a later out-migration from Africa, which could reasonably be divided into more or less the equivalents of West and East Eurasian groups, although of course recognizing that there are many intermediates. Here the problem arises of distinguishing black Africans as a racial group; it doesn't work because it is a paraphyletic classification. In other words, under a phylogenetic classification, considering black Africans as a single racial group would require one to include every living person on Earth within that single African "race", because the genetic variation of the rest of the world represents essentially a single subtree within that of Africa. Also, it has long been known that groups such as the Khoisan were as different from other sub-Saharan groups as are Europeans and Asians (though even with the Khoisan the distinction is no longer so clearcut, as a large amount of intermarriage with both Europeans and Bantu-language speakers has occurred over the last three centuries).
Race in biomedicine
There is an active debate among biomedical researchers about the meaning and importance of race to their research.
Several questions are being considered:
The primary impetus for considering race in biomedical research is the possibility of improving the prevention and treatment of diseases. Many previous studies have observed that disease susceptibility and environmental responses vary by race. Thus, some researchers believe that race may be an informative category for biomedical research. Others fear that the use of racial categories in research may cause social harm.
In biomedical research, the 2000 US census definition of race is often applied. This grouping recognizes five races: black or African American, white, Asian, native Hawaiian or other Pacific Islander, and American Indian or Alaska native. However, this definition is inconsistently applied between studies.
From the perspective of genetics, human population structure is the result of patterns of mating. Historically, the greatest influence on mating patterns is geography. Genetic research has shown that the greatest genetic differentiation among humans corresponds with continental groupings. To the extent that racial labels correspond with continental groups, some argue that they are informative for biomedical research.
In multiracial societies such as the United States, racial groups also differ by social and cultural correlates such as economic status and access to healthcare. These factors are believed to explain some of the differential health care outcome between races. An open area of investigation is whether racial differences persist in studies where social and cultural correlates are taken into account.
The existence of genetic differences among races is well accepted. In general, genetic clusters exist which correspond tightly to the census definition of race and to self-identified ancestry. One large exception to this correspondence is that South, Central, and West Asians (e.g. Asian Indians) cluster with Europeans and are separate from East Asians. The association between race and genetics also breaks down for groups such as Hispanics, which exhibit a pattern of geographical stratification of ancestry. The biomedical relevance of genetic differences among races is a matter of debate. Some researchers argue that the available evidence supports the notion that some of the genetic differences between races has biomedical significance, and thus should be studied.
An alternative view argues that the underlying genetic-cluster categories can be used in lieu of racial labels for biomedical purposes. Proponents of this view argue that by directly examining the genotype, the problem of using racial labels can be avoided. Moreover, they argue that genotyping is more reliable than using self-identified race as a proxy for ancestry. Some fear that the use of racial labels in biomedical research runs the risk of unintentionally exasperating health disparities.
Proponents of using race in biomedical research argue that ignoring race will be detrimental to the health of minority groups. They argue that disease risk factors differ substantially between racial groups, that relying only on genotypical classes ignores non-genetic factors that impact health, and that minorities would be poorly represented in clinical trials if race were ignored.
Because individual geography, culture, religion, political association and, above all, heredity can change, racial purity, the concept that wholly distinct racial groupings exist, has little meaning from the perspective of evolutionary biology.
Indeed, it is preferable when considering biological relations to think in terms of populations, and when considering cultural relations to think in terms of ethnicity, rather than of race. Instead of classing people into one "group", say "Caucasians" or Europeans you have Britons, Frenchmen, Germans, Nords, western Slavs and Celts rather than having a term implying a ("possible") ancestor group in the Caucasus that is too distant for consideration and moreover reaching to groups including eastern Slavs, Roma,Persians and Indians, and others that differ notably, both culturally and to a lesser yet still noteworthy extent physically, from the aforementioned ethnic groups There can be as much difference between two ethnicities grouped into a "race" as between either of those and an ethnic group grouped (often arbitrarily) into another "race."
da:Race de:Rasse fr:Race lt:Rasė nl:Ras (mensheid) ja:人種 pl:Rasa fi:Rotu sv:Ras zh:种族