Race - Fact Or Fiction?

The excellent Mixing Memory recently had a post commenting, prompted by some comments from Fido the Yak, on MIT cognitive psychologist and best-selling author Steven Pinker’s remarks about group differences in his answer to the Edge Annual question. It’s a little old now, but I thought the questions they raised about Pinker’s comments, and the notion of race, provided reason enough to say a little these ideas, and to clear up some confusion.

Fido says, “I believe [Pinker’s] a sexist, a racist and willfully ignorant of certain facts of evolutionary science” (these are serious charges that warrant careful substantiation); Mixing Memory adds, “First of all, Fido gets Pinker exactly right. As I've said many times, Pinker has a nasty habit of speaking authoratatively about topics on which he is anything but an authority (like, say, gender differences in mathematical ability)… Like Pinker, I'm not an expert in genomics, or anything remotely related to genetics, but unlike Pinker, I'm not going to comment on the issues discussed in the forum as though I am an expert.” Both Mixing Memory and Fido mention a recent forum on race, where the experts set the record straight on race, supposedly. When Fido says, “when I want to learn about population genetics, I consult a population geneticist, Luigi Luca Cavalli-Sforza, for instance, who would give me plenty of reasons to doubt that what Pinker says approximates anything I should pay attention to”, he gives the impression that the weight of expert opinion refutes Pinker. But it doesn’t take much searching to challenge this idea (and NOT [D.J. important corrective word added] through selective picking of contrarian, fringe experts), and in this post I’ll let the experts speak for themselves.

In 2002, Daedalus published two essays, one by Ernst Mayr, the other by James Crow, both on race.

Mayr was until his death the doyen of American evolutionary biology, and one of the architects of the evolutionary synthesis. This doesn’t make him infallible, but he’s not a crank either. Here’s some selected quotes from his essay:

“There is a widespread feeling that the word “race” indicates something undesirable and that it should be left out of all discussions. This leads to such statements as “there are no human races”. Those who subscribe to this opinion are obviously ignorant of modern biology. Races are not something specifically human; races occur in a large percentage of species of animals … The terms “subspecies” and “geographic races” are used interchangeably in [the] taxonomic literature.”

James Crow is a distinguished and widely respected population geneticist; here’s some more extensive quotes from his essay:

“If we randomly choose a pair of bases from corresponding sites in two persons, 99.9 percent of the time they will be the same. This percentage depends only slightly on whether the two people are from the same or from different continents, from the same or from different population groups … Analysis of DNA allows us to measure with some precision the genetic distance between different populations of human beings. By this criterion, Caucasians and Asians are relatively similar, whereas Asians and Africans are somewhat more different. The differences between the groups are small–but they are real … Just as there are great differences among individuals, there are average differences, usually much smaller, between groups. Italians and Swedes differ in hair color. Sometimes the differences are more conspicuous, such as the contrasting skin color and hair shape of Africans and Europeans. But, for the most part, group differences are small and largely overshadowed by individual differences. Biologists think of races of animals as groups that started as one, but later split and became separated, usually by a geographical barrier. As the two groups evolve independently, they gradually diverge genetically. The divergences will occur more quickly if the separate environments differ, but they will occur in any case since different mutations will inevitably occur in the two populations, and some of them will persist… In much of the animal world, however, and also in the human species, complete isolation is very rare. The genetic uniformity of geographical groups is constantly being destroyed by migration between them. In particular, the major geographical groups – African, European, and Asian – are mixed, and this is especially true in the United States, which is something of a melting pot. Because of this mixing, many anthropologists argue, quite reasonably, that there is no scientific justification for applying the word “race” to populations of human beings. But the concept itself is unambiguous, and I believe that the word has a clear meaning to most people. The difficulty is not with the concept, but with the realization that major human races are not pure races. Unlike those anthropologists who deny the usefulness of the term, I believe that the word “race” can be meaningfully applied to groups that are partially mixed. Different diseases are demonstrably characteristic of different racial and ethnic groups. Sickle cell anemia, for example, is far more prevalent among people of African descent than among Europeans. Obesity is especially common in Pima Indians, the result of the sudden acquisition of a high-calorie diet to which Europeans have had enough time to adjust. Tay-Sachs disease is much more common in the Jewish population. There are other examples, and new ones are being discovered constantly. The evidence indicating that some diseases disproportionately afflict specific ethnic and racial groups does not ordinarily provoke controversy. Far more contentious is the evidence that some skills and behavioral properties are differentially distributed among different racial groups. There is strong evidence that such racial differences are partly genetic, but the evidence is more indirect and has not been convincing to everyone.”

We can at least conclude from these comments that the concept of race is not dismissed by all serious biologists; for sure, scientists such as Richard Lewontin and others reject the usefulness of the concept of race, but that view doesn’t win by default. Straight off we should be suspicious of the quick dismissal of the concept of race, and also the charge that Pinker is being ignorant, willfully or not, of evolutionary science. He might not agree with Lewontin and company, but that doesn’t automatically make him wrong.

However, without some clarification and qualification the claims of Mayr and Crow might be objected to (even with the clarifications and qualifications the claims might still be objectionable to some – reasonable people can disagree!). Here’s how Steve Olson and Michael Bamshad begin an article entitled ‘Does Race Exist?’ in Scientific American:

“Look around on the streets of any major city, and you will see a sampling of the outward variety of humanity: skin tones ranging from milk-white to dark brown; hair textures running the gamut from fine and stick-straight to thick and wiry. People often use physical characteristics such as these-along with area of geographic origin and shared culture--to group themselves and others into "races." But how valid is the concept of race from a biological standpoint? Do physical features reliably say anything informative about a person's genetic makeup beyond indicating that the individual has genes for blue eyes or curly hair?
The problem is hard in part because the implicit definition of what makes a person a member of a particular race differs from region to region across the globe. Someone classified as "black" in the U.S., for instance, might be considered "white" in Brazil and "colored" (a category distinguished from both "black" and "white") in South Africa.

Yet common definitions of race do sometimes work well to divide groups according to genetically determined propensities for certain diseases. Sickle cell disease is usually found among people of largely African or Mediterranean descent, for instance, whereas cystic fibrosis is far more common among those of European ancestry. In addition, although the results have been controversial, a handful of studies have suggested that African-Americans are more likely to respond poorly to some drugs for cardiac disease than are members of other groups.

Over the past few years, scientists have collected data about the genetic constitution of populations around the world in an effort to probe the link between ancestry and patterns of disease. These data are now providing answers to several highly emotional and contentious questions: Can genetic information be used to distinguish human groups having a common heritage and to assign individuals to particular ones? Do such groups correspond well to predefined descriptions now widely used to specify race? And, more practically, does dividing people by familiar racial definitions or by genetic similarities say anything useful about how members of those groups experience disease or respond to drug treatment?

In general, we would answer the first question yes, the second no, and offer a qualified yes to the third.”

The authors then go on to discuss some specific studies:

“One of us (Bamshad), working with University of Utah scientists Lynn B. Jorde, Stephen Wooding and W. Scott Watkins and with Mark A. Batzer of Louisiana State University, examined 100 different Alu polymorphisms in 565 people born in sub-Saharan Africa, Asia and Europe. First we determined the presence or absence of the 100 Alus in each of the 565 people. Next we removed all the identifying labels (such as place of origin and ethnic group) from the data and sorted the people into groups using only their genetic information.

Our analysis yielded four different groups. When we added the labels back to see whether each individual's group assignment correlated to common, predefined labels for race or ethnicity, we saw that two of the groups consisted only of individuals from sub-Saharan Africa, with one of those two made up almost entirely of Mbuti Pygmies. The other two groups consisted only of individuals from Europe and East Asia, respectively. We found that we needed 60 Alu polymorphisms to assign individuals to their continent of origin with 90 percent accuracy. To achieve nearly 100 percent accuracy, however, we needed to use about 100 Alus.

Other studies have produced comparable results. Noah A. Rosenberg and Jonathan K. Pritchard, geneticists formerly in the laboratory of Marcus W. Feldman of Stanford University, assayed approximately 375 polymorphisms called short tandem repeats in more than 1,000 people from 52 ethnic groups in Africa, Asia, Europe and the Americas. By looking at the varying frequencies of these polymorphisms, they were able to distinguish five different groups of people whose ancestors were typically isolated by oceans, deserts or mountains: sub-Saharan Africans; Europeans and Asians west of the Himalayas; East Asians; inhabitants of New Guinea and Melanesia; and Native Americans. They were also able to identify subgroups within each region that usually corresponded with each member's self-reported ethnicity.

The results of these studies indicate that genetic analyses can distinguish groups of people according to their geographic origin. But caution is warranted. The groups easiest to resolve were those that were widely separated from one another geographically. Such samples maximize the genetic variation among groups. When Bamshad and his co-workers used their 100 Alu polymorphisms to try to classify a sample of individuals from southern India into a separate group, the Indians instead had more in common with either Europeans or Asians. In other words, because India has been subject to many genetic influences from Europe and Asia, people on the subcontinent did not group into a unique cluster. We concluded that many hundreds--or perhaps thousands--of polymorphisms might have to be examined to distinguish between groups whose ancestors have historically interbred with multiple populations.

The human race
Given that people can be sorted broadly into groups using genetic data, do common notions of race correspond to underlying genetic differences among populations? In some cases they do, but often they do not. For instance, skin color or facial features--traits influenced by natural selection--are routinely used to divide people into races. But groups with similar physical characteristics as a result of selection can be quite different genetically. Individuals from sub-Saharan Africa and Australian Aborigines might have similar skin pigmentation (because of adapting to strong sun), but genetically they are quite dissimilar.”

Studying race isn’t just of mere intellectual interest – it can also prove useful in biomedicine:

“But the importance of group membership as it relates to health care has been especially controversial in recent years. Last January the U.S. Food and Drug Administration issued guidelines advocating the collection of race and ethnicity data in all clinical trials. Some investigators contend that the differences between groups are so small and the historical abuses associated with categorizing people by race so extreme that group membership should play little if any role in genetic and medical studies. They assert that the FDA should abandon its recommendation and instead ask researchers conducting clinical trials to collect genomic data on each individual. Others suggest that only by using group membership, including common definitions of race based on skin color, can we understand how genetic and environmental differences among groups contribute to disease. This debate will be settled only by further research on the validity of race as a scientific variable.

A set of articles in the March 20 issue of the New England Journal of Medicine debated both sides of the medical implications of race. The authors of one article--Richard S. Cooper of the Loyola Stritch School of Medicine, Jay S. Kaufman of the University of North Carolina at Chapel Hill and Ryk Ward of the University of Oxford--argued that race is not an adequate criterion for physicians to use in choosing a particular drug for a given patient. They pointed out two findings of racial differences that are both now considered questionable: that a combination of certain blood vessel-dilating drugs was more effective in treating heart failure in people of African ancestry and that specific enzyme inhibitors (angiotensin converting enzyme, or ACE, inhibitors) have little efficacy in such individuals. In the second article, a group led by Neil Risch of Stanford University countered that racial or ethnic groups can differ from one another genetically and that the differences can have medical importance. They cited a study showing that the rate of complications from type 2 diabetes varies according to race, even after adjusting for such factors as disparities in education and income.

The intensity of these arguments reflects both scientific and social factors. Many biomedical studies have not rigorously defined group membership, relying instead on inferred relationships based on racial categories. The dispute over the importance of group membership also illustrates how strongly the perception of race is shaped by different social and political perspectives.

In cases where membership in a geographically or culturally defined group has been correlated with health-related genetic traits, knowing something about an individual's group membership could be important for a physician. And to the extent that human groups live in different environments or have different experiences that affect health, group membership could also reflect nongenetic factors that are medically relevant.”

In June 2005, the United States Food & Drug Administration approved NitroMed’s BiDil for the treatment for heart failure in African-Americans only. This was based on data showing greater benefit in self-identified black patients. Let’s assume that there is a genetic component this difference (it’s common for genetic profiles to affect the effects of drugs, as revealed by pharmacogenetics, although it could be an environmental factor). The enhanced effect in black compared with white patients is not the result of the fact that all black individuals have one version of a given gene and all white individuals have a different one – there aren’t these discrete genetic groups. It’s just that being black, by virtue of ancestry, means that you’re more likely to possess this given genetic variant, which is the view of race validated by Olson and Bamshad. Race here is just functioning as a proxy measure of genetic identity, but it’s just one of many possible levels of resolution for looking at humanity. Taking what we might call the Gray’s Anatomy approach, we might treat all humans as the same, so when they get condition X they receive drug Y. But the facts of human variation make a nonsense of this approach, and we have the tools to take a more fine-grained approach to matching drugs with genetic profiles. At the other extreme, the finest resolution we could achieve would be the complete genome sequence of every individual along with knowledge of it varies from every other genome. This is currently unfeasible. But there are intermediate levels of resolution, and race seems to be one. Of course, it would be best to identify the genetic underpinnings of the differential response to BiDil among blacks and whites, and to then test heart failure patients for the presence of these genes, prescribing BiDil to only those with the ‘right’ combination. If this could be achieved, the efficacy of BiDil would increase even further in this tightly defined group. But in the meantime, the facts of ancestry mean that the increased statistical likelihood that black individuals will carry genes that enhance response to BiDil can be used to bring benefit to heart failure patients or at least one race.

It’s time to summarise the case for race. Races are genetically distinct groups: there aren’t such groups to even begin to correspond to standard racial classifications. However, “be used to distinguish human groups having a common heritage and to assign individuals to particular ones”; “Given that people can be sorted broadly into groups using genetic data, do common notions of race correspond to underlying genetic differences among populations? In some cases they do, but often they do not.”. And race has apparent worth in medicine, as the DiBil case demonstrates.

Now, if you can accept the above, and then go back to what Pinker wrote, and what Armand Leroi wrote (on Edge and in the NYT), then I think it will seem a lot more reasonable, a lot less racists, and something worthy of at least thinking – not rejecting out of hand – even if you end up disagreeing on some or all points.

Thinking about race
Whatever your take on all this is, race is clearly an emotive, hot-button topic, and views on race are susceptible to ideological influence in a number of ways. Indeed, Lewontin’s ideological commitments have long been highlighted as colouring his scientific view of the world (a compliment he has returned to his critics). I’ll lay my cards on the table and say that I think that Lewontin is unduly ideological in his writings, and his views on some scientific topics are more motivated by a sincerely held concern for social justice than scientific truth (maybe some would see this as a good compromise, but here I’m assessing a scientific argument free from ideological commitments – but I suppose some will be imputed to me anyway by association with the views above). Jonathan Marks, who was on in the panel on race linked to above, has responded to evolutionary psychology with “Boy, this shit ticks me off” (a sentiment that Lewontin would echo), and this suggests an attitude that would also want to reject the idea of race (I realise this isn’t an argument, more a sociological observation). Interestingly, Mixing Memory also doesn’t like evolutionary psychology, or Steve Pinker in particular. I suspect that the same sort of general outlook motivates both the rejection of ev. psych. and the idea of race (“Yes”, will be the response: “They’re both a load of rubbish!”).

Responding to criticisms of the notion of race doesn’t require this sort of line of enquiry, but I think it’s important to identify why people might be driven by perhaps non-scientific reasons to reject certain findings or ideas (Pinker’s The Blank Slate is an extended attempt at just such an exercise, and also serves as a corrective to some of the misplaced fears surrounding the idea of human nature and the ideas of ev. psych. in particular; I have to say that I think Pinker is spot on here, but again that doesn’t really have anything to do with whether the argument about race is good or not). As I say, I’m trying to understand why people are so keen to reject certain ideas, even those they perhaps do not understand very well.

In the case of Mixing Memory one doesn’t have to look far. An earlier post on MM was entitled ‘I’m a racist: one cognitive scientist’s thoughts on racism part 1’. I’m really not trying to take a cheap shot here by merely putting the title in – the post is not a proud announcement of racist views, but a soul-searching examination of the pernicious effects of growing up in a racist climate even when you explicitly reject the racism you are surrounded by. It’s all commendable stuff. But it does provide a clue as to why MM is so sensitive about issues of race.

I didn’t grow up in an overtly racist environment, attended a mixed school, had and have black and Asian friends (I’m not saying, “See, I couldn’t be racist!”, just pointing out that mixing with people of different ethnicities to me was and is common), and now happen to have a Chinese girlfriend (well, British born, but of Chinese ethnicity). I’m concerned about racism and racial attitudes, but am relaxed about my racial attitudes, in that I really don’t think I have any racial hang-ups or latent racism (I know this could all be self-serving delusion, but I have no evidence that I’m racists and plenty of clues that I’m not!). Perhaps if I was writing from the deep South 40 years ago I would much more sensitive to talking about race, and might want to be able to comfortably ignore the findings of race being produced by science (imagine the science of today was available then). But this doesn’t make the science wrong. As understandable as it is that you don’t want racial differences to be highlighted and magnified because of the potentially harmful uses to which such ideas can be put is not an argument against the validity of the science of race. In any case, the ideas discussed above don’t justify racism at all, and in fact, as Pinker points out, it’s a pretty weak idea of racial equality that depends of the fact of genetic similarity (see Crow on related points) – we shouldn’t treat people well because they share the same genes us as, but because they’re humans and are deserving of the same treatment as ourselves regardless of how similar or different they are from us. And it’s always wrong to treat an individual as if they were an abstract average of the group you or they decide they belong to (whether that be based on race, sex, sexuality and so on).

Perhaps when we’re being listened to by racists we might want to avoid using the phrase ‘racial differences’, but among reasonable people we should be able to discuss the science of race sensibly, without racist connotations, and such discussions might have important health consequences, as the BiDil story illustrates.