Breaking news: do human races exist after all?

January 23, 2010 at 10:27 pm (thinking) (, , , , , , )

With the recent focus on the problems of racism, discussing whether races exist has become something of a dangerous game.  Because we don’t believe that people should be discriminated against on the basis of race, it has been pushed that races don’t really exist – that it is a social construct.  This idea has been reproached by Nevin Sesardic in a peer-reviewed paper titled “Race: A Social Destruction of a Biological Concept“, where he argues that races do exist, but that the biological concept has been usurped by people trying to justify racism.  If only we went back to the biological concept, he argues that we would find races are real.

Now I know a fair bit about genetics, and particularly human genetics, so I’m going to chip in with my own opinion, and leave the reader to examine whether it fits with the race concept proposed in the above paper.  I’ll start by stating some general facts:

  • There is significant genetic variation in people.
  • This variation is not “discrete” (i.e. caucasian and negro) but a continuous change between people.  For example, skin tone varies continuously across the world with every shade appearing somewhere.
  • There are real physical differences in people that are caused by these differences in genetics.  As an addendum: mental and emotional abilities are physically determined and so can be strongly influenced by genetics, too.
  • All of this variation is carried on genes which can be transferred to children regardless of the parents “race class”.

What all this means is that yes, differences between people exist; and yes, they can be important.  But there are no boundaries between people; if a good trait is found, it can and will spread to everyone eventually (and already has several times).  Additionally, complex behaviours such as intelligence are determined by so many factors – a good proportion of which are not genetic – that any difference in ability has to be slight, and will be rectified by interbreeding in any case.  There is no evidence that such factors exist, because the variation within a “race” is so much greater than the variation between different each “race”.  And because of the continuous transfer of genes that has been going on, there is no reason to believe that any difference would exist anyway.

Sesardic argues that although differences between races are small, they are measurable, and they do tell you things about the genetics of a person (in a weak statistical sense). So basically, from knowing someone’s genotype you can guess correctly which race they are.  He argues that this makes the “variation between” and “variation within” argument superfluous because the difference is still measurable.

My recent research is relevant here.  I have been taking genetic data, and trying to figure out which people are similar to which other people.  With current statistical technology based on looking at the proportion of our genomes we share with other people, we can tell the difference between French and Italians, between north Chinese and south, and between people from different Polynesian islands.  We can certainly tell an African American from a European American.  Interestingly, we can’t tell apart several Indian castes with distinct labels.  We can even build a “tree” of how different populations are from each other, with the continents coming out quite clearly, and Africa being the most diverse continent (supporting the “out of Africa” theory).

So this means Sesardic is right that measurable differences exist (we knew this).  You can call different “branches of the tree” races, if you want to.  But where is the correct place to “chop the branches off”?  Is it at “white vs black”?  How about the people with moderate pigmentation, e.g. Latinos, Asians, etc?  There are only two points on the tree that mean anything: the populations, i.e. people who are genetically equivalent (from a statistical point of view) such as French, Italian, etc. (actually, we can often find multiple groups within a nation; e.g. there are 3 main groups of French people found by our current analysis).  The other is to group all people together.  Everything else is introducing arbitrary distinctions;  you can just choose whether two populations should be grouped or split.

So do races exist?  I think it’s a silly question.  Populations exist.  Differences exist, which just means that our human population is not all the same (a good thing!).  What value is there to placing any other distinction between groups of people?  It doesn’t tell you anything useful about them; knowing someone is “black” only tells you about their skin colour and some weak (useless) statistical relation in their genetics.  We would need a label for every valid combination of people; a single Frenchman would be all of Northern French, French, Northern European, European, North Eastern Eurasian, Second Migration from Africa, etc. Which one is his “race”?

Knowing someone’s culture is a different matter of course.  Because we typically associate with people who are similar to us, knowing that someone is white tells lets you guess their culture and hence what opinions and background they might have.  But that is no better than knowing they are from Cornwall – it is just that people with similar childhood experiences and friendship groups are similar.  It is not race, but the culture that a person feels affinity for that determine the important things about him.  A person of Asian descent brought up to be “British” is a lot more similar in attitude and culture to a person of Saxon descent who is “British”, than to someone of Asian descent living in India (even their 3rd cousin).

A biological concept of “race” might or might not be of some scientific use, but it doesn’t have any place outside of academia, so why not use a different word?  In the meantime, we know people are influenced by language, so lets continue to remove the race barrier and let people be people.  As long as people are allowed to be different.

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8 Comments

  1. JL said,

    This idea has been reproached by Nevin Sesardic in a peer-reviewed paper titled “Race: A Social Destruction of a Biological Concept“, where he argues that races do exist

    Sesardic does not argue that races exist. He simply demonstrates that the arguments used to claim that races do not exist are fallacious and unsupported by data. He seems to be agnostic about the existence of races.

    complex behaviours such as intelligence are determined by so many factors – a good proportion of which are not genetic – that any difference in ability has to be slight, and will be rectified by interbreeding in any case. There is no evidence that such factors exist, because the variation within a “race” is so much greater than the variation between different each “race”. And because of the continuous transfer of genes that has been going on, there is no reason to believe that any difference would exist anyway.

    The idea that there cannot be complex genetic differences between traditional racial categories because there’s more genetic variation within them than between them is known as Lewontin’s Fallacy. If you try to group individuals from different populations by looking at a single genetic locus, you won’t be very successful, but if you examine a large number of loci, there’s no chance of misclassification if the populations in question have been more or less separated from each other for millennia. This is because there are many sets of alleles that are common in one population and rare in another. Variation in a large number of genetic loci may also result in complex heritable behavioral differences. (More on Lewontin’s Fallacy here: http://www.goodrumj.com/Edwards.pdf.)

    There are differences in average IQ between different self-identified racial groups, and at least in America social race corresponds well to different genetic clusters. Considering that IQ is highly heritable (within a population), and that all the testing says that there are average differences between races, the null hypothesis should be that the differences are at least partly genetic.

    There is no evidence of any “continuous transfer of genes” between distant populations. It would not be so easy to classify populations into ancestral categories if there had been constant gene flow. In contemporary America not more than a couple of percent of marriages are interracial, so interbreeding will not wipe out genetic differences between populations in the foreseeable future.

  2. thinkingdan said,

    Thanks! These are really interesting points. I’ll try to address them in the context of my argument.

    Firstly, I think you are right that Sesardic was merely opening the debate about races, rather than claiming that they exist. Scientifically, I think he is correct to do so. My points are about what this means in a society context.

    My point relating to Lewontin’s Fallacy is that there are measurable differences between populations, sub-populations and so on down to the family level. I don’t find it clear that what we call “race” has any special value compared to the other levels that we could consider differences at; race, nationality, cultural identity, language etc. all tell you similar information about genes – differences exist, in a weak statistical sense, between all of them. The question is whether a label at a given level helps us scientifically or socially.

    IQ is a particularly difficult metric because it is hugely dependent on upbringing, and it isn’t clear what it really measures. Neverless, it has the strongest social implications for racism. I agree that scientifically we should consider it possible that real differences exist, but extreme care is needed in disseminating any results on this: it is known that the perception of IQ determines IQ to a strong degree. We can’t separate such social feedback from the scientific process. So the correct null hypothesis might be that no real difference exists, because assuming a difference can induce a difference. (This feedback process is actually the most important part of my point, and I hadn’t realised that before).

    Finally, there is “continuous transfer of genes” – although it isn’t at all uniform. A few percent interbreeding is more than sufficient to maintain gene flow under most genetic models (e.g. it prevents speciation), and if there is selection involved then good genes can transfer extremely quickly and effectively. It is true that genetic differences will still persist in the presence of such gene flow, but my argument is that “races” are not the natural description of these differences, “populations” are.

    • S Blumenthal said,

      ***IQ is a particularly difficult metric because it is hugely dependent on upbringing, and it isn’t clear what it really measures.***

      Surprisingly, behavioural genetics studies show the shared environment appears to have fairly limited influence on intelligence as measured in adulthood (see studies by Robert Plomin, David C Rowe & Judith Rich Harris).

      In terms of what it measures, neuroscientists like UCLA’s Paul Thompson are making progress on this.

      “The UCLA researchers took the study a step further by comparing the white matter architecture of identical twins, who share almost all their DNA, and fraternal twins, who share only half. Results showed that the quality of the white matter is highly genetically determined, although the influence of genetics varies by brain area. According to the findings, about 85 percent of the variation in white matter in the parietal lobe, which is involved in mathematics, logic, and visual-spatial skills, can be attributed to genetics. But only about 45 percent of the variation in the temporal lobe, which plays a central role in learning and memory, appears to be inherited.

      Thompson and his collaborators also analyzed the twins’ DNA, and they are now looking for specific genetic variations that are linked to the quality of the brain’s white matter. The researchers have already found a candidate–the gene for a protein called BDNF, which promotes cell growth. “People with one variation have more intact fibers,” says Thompson.”

      http://www.technologyreview.com/biomedicine/22333/page2/

      See also, NEUROBIOLOGY OF INTELLIGENCE: SCIENCE AND ETHICS Nature Reviews Neuroscience 5, 471-482 (June 2004)

      http://www.yale.edu/scan/GT_2004_NRN.pdf

      ***but extreme care is needed in disseminating any results on this: it is known that the perception of IQ determines IQ to a strong degree.***

      A recent meta analysis by Wicherts & de Haan found there is little support for the stereotype threat theory. Further, of the 55 published and unpublished studies reviewed, the authors found clear signs of publication bias (studies showing no stereotype threat were less likely to be published). They commented:

      ““The effect varies widely across studies, and is generally small. Although elite university undergraduates may underperform on cognitive tests due to stereotype threat, this effect does not generalize to non-adapted standardized tests, high-stakes settings, and less academically gifted test-takers.”

      http://www.isironline.org/meeting/pdfs/program2009.pdf#page=68

      ***The question is whether a label at a given level helps us scientifically or socially.***

      It probably doesn’t, but policy makers tend to analyse data in these terms and politicians look for signs of inequality. Because it is assumed there are no group differences, inequality tends to be atttribtued to unfairness.

      http://www.boston.com/news/local/breaking_news/2010/01/mit_lags_in_hir.html

      However, as Professor Steve Hsu notes here, while there is significant overlap between populations, average differences lead to large discrepancies at the tail of the distribution.

      “On the other hand, for most phenotypes (examples: height or IQ, which are both fairly heritable, except in cases of extreme environmental deprivation), there is significant overlap between different population distributions. That is, Swedes might be taller than Vietnamese on average, but the range of heights within each group is larger than the difference in the averages. Nevertheless, at the tails of the distribution one would find very large discrepancies: for example the percentage of the Swedish population that is over 2 meters tall (6″7) might be 5 or 10 times as large as the percentage of the Vietnamese population. If two groups differed by, say, 10 points in average IQ (2/3 of a standard deviation), the respective distributions would overlap quite a bit (more in-group than between-group variation), but the fraction of people with IQ above some threshold (e.g., >140) would be radically different.”

      http://infoproc.blogspot.com/2008/01/no-scientific-basis-for-race.html

      • thinkingdan said,

        Thankyou for the very informative and level comment. I replied to your other comment with a response to that part: https://thinkingdan.wordpress.com/2010/02/13/social-feedback-an-iq/#comment-102 . I’ll respond to the remaining parts here. I should make it clear that I’m not sure that I disagree, but that it is worth playing Devil’s advocate.

        Regarding what IQ is, thanks for the links. It is plainly obvious that some inherited factors affect IQ, and that IQ will be selected for in some environments more than others. So we would expect differences. IQ is still fuzzy, of course, although I’m impressed at the attempts to figure out “how” fuzzy it really is.

        I responded to the Wicherts and de Haan study in the other comment; my basic ponit is that I can still find uncertainty there.

        Steve Hsu’s point is essentially the same as mine: clearly populations are different, which means races are also different. However, we see races and therefore discrimination is easy. We don’t really see populations. I would argue that we should move away from race-based measures and focus on population based analysis, which would have smaller differences that we might have some hope of untangling.

        I like your point about labels being important to society because they are important to policy makers. That is indeed a social aspect that needs further study, and I can imagine a counter-argument to my “null hypothesis of equality” based on it. Although we aught to be able to expect that policy makers will make sensible use of these statistics (ha…) .

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