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7.5: Race

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  • All the categories of human variation in this section (age, sex, disease, race) have some basis in biology, but this last one is the most arbitrary out of all of them. The decision to group people based on superficial visual characteristics is not founded in absolute biological difference, but in a long history of cultural difference. Race is culture, not biology. We have a cultural tendency to cram human variation into racial categories.

    We are stuck with lots of baggage from scientists who got it wrong.


    Figure \(\PageIndex{1}\) - Linnaeus on human races

    In this schema Linnaeus sets up categories based on geography and cultural stereotypes, and mixes them in with biological taxonomy. This error of conflating culture and biology has been repeated for centuries, and continues to this day.

    Physical anthropology is great at explaining why biological divisions between human races don't exist, but we can also suggest how we got into this mess in the first place, and why humans might be predisposed to getting it wrong. Race is an optical illusion, and our dependence on creating the world based on what we see can be explained in terms of the evolution of primates and our shift in sensory priorities from olfaction to vision. Compared to most mammals primates see better than they smell. The visual predation hypothesis suggests how the forward facing eyes of small carnivores predisposed them towards the binocular vision required by life in the trees. The consequences of failing to predict the correct distance of a branch can be deadly, and genes for visual acuity tend to get passed on to the next generation. Millions of years adapting to life in the trees led to primates generalized diet, including fruits. Color distinctions, especially in diurnal primates, are useful to discern whether fruit is ripe from a long distance. As we came down from the trees, the neocortex used in vision was re-purposed for increased cultural complexity such as social structure and tool use, and although encephalization has tripled the sized of our brains, we retain the vestigial primate emphasis on vision over smell. We emphasize the visually apparent differences between people because that's what our species is biologically set up to do. Dogs judge other dogs by their smell. Whales judge other whales by their songs. Bats judge other bats through echolocation. Spiders judge other spiders by their vibrations. Duck-billed platypuses judge others by their electromagnetic radiation. Trees judge other trees through mycelial networks. We look at skin color, body type, and facial features. These visual markers may seem critical to us, but they don't represent enough biological difference to separate people into significant groups.


    Racism is the belief that there are discrete racial groups that can be ranked from good to bad. I have a pure-bred dog with an AKA pedigree and all, and it kind of creeps me out a little to see how seriously some of these dog breeders take their work, it reminds of the eugenics movement. Eugenics is the application of racial ideas to public policy. We blame Hitler for the most horrible atrocity in history while striving to create the master race, but many of his ideas came from the eugenics movement in the United States.


    • Article about California's role in the eugenics movement
    • It was also popular in Latin America, here's an example of eugenics in Veracruz, Mexico
    • Update on Racial profiling in NYPD stop and frisk policy
    • Traffic enforcement in San Diego, California An analysis of SDPD vehicle stops in 2014 and 2015
    • Op Ed about Census racial categories

    Eugenics and Donald Trump

    Race Without Racism?

    I don't think it's possible to study race without taking sides, either for or against racism, but the study of human variation does lead to some "neutral" generalizable rules about the visual characteristics we use to determine race. Most forensic anthropologists argue that they can empirically determine the race of a bone, and they get it right about 2/3 of the time.

    Exercise \(\PageIndex{1}\)

    • Review Dennis O'Neil on Non random mating, an argument against people tending to choose mates from within their own race is the research on HLA and the immune system
    • Distribution of Y chromosomes among Native North Americans: A study of Athapaskan population history Question: Why does Y chromosome analysis reveal a greater admixture with Europeans than MtDNA analysis?
    • Red hair is a good example of convergent evolution, people in many different regions around the world have different kinds of red hair, and our culture deals with it in radically different ways. Read Wikipedia on red hair
    • Genetic diversity in Latinos enables chromosome mapping

    Gloger's Rule

    Mammals tend to have darker skin towards the equator and lighter skin towards the poles.

    Exercise \(\PageIndex{2}\)


    Read Peter Elias' research on filaggrin mutations, another protein like melanin that helps protect the skin.

    Remember, the fact that we can study skin color scientifically doesn't mean that races are scientifically valid categories. Races are cultural defined, not biologically. Humans, as primates, tend to be visually oriented, so it makes sense how we might create folk taxonomies based on colors.

    • Article on different genes that cause skin color


    Other visual ways of categorizing humans is by body types and features, and many variations can be explained through natural selection. Allometry is the change in body shape when a population gets bigger or smaller depending on environmental condition. We've already had a great example in paleoanthropology of Homo floresiensis, the "Hobbit", a small hominin found on a small island in Indonesia. We attribute the small size to insular dwarfism, a principle seen in other island species; the limited island resources select for small body size.

    Exercise \(\PageIndex{3}\)

    Read more about allometry

    Bergman's Rule

    To understand Bergman's rule think of the best and worst radiator design, and ways to maximize and minimize the surface area to mass ratio which allows heat to dissipate or be conserved. Natural selection tends to make humans that way too. If you live in hot place and need to dissipate heat, you tend to have more surface area and less mass; you're gracile. If you live in a cold place and need to conserve heat, you tend to have more mass and less surface area; you're robust. This is the best explanation for the robusticity of Neandertals: they evolved during the ice ages. The principle also explains some differences between modern regional populations.


    Figure \(\PageIndex{2}\) - A car radiator

    Allen's Rule

    The radiator analogy works for Allen's rule too, the longer the appendages the better they work to release heat, and the shorter the appendages, the more heat is conserved. So people who live in cold climates for long periods of time, tend to have shorter arms and legs than people who live in hot climates.

    These rules apply to most animal. Bears are great example: compare the long-legged tropical Sun Bear to the short-legged Polar bear. Human populations tend to follow this, for example the arctic Inuit tend to be stocky with short arms and legs compared to the Woodabe of sub-Saharan Africa who tend to be tall and thin. But there are some counter examples as well, the Aka live fairly close to the Woodabe, but they tend to be short. This counter example is probably best explained as part of the amazing human diversity on the African continent, where human evolution has occurred for the longest.

    Exercise \(\PageIndex{1}\): Imagination Actions

    Take this quiz about the history of slavery in the US, and write about what you learned.


    • allometry
    • Allen's rule
    • Bergman's rule
    • blood types
    • cline
    • endogamy
    • essentialism
    • exogamy
    • eugenics
    • Gloger's rule
    • haplogroup
    • race
    • racism
    • Y chromosome