Understanding Race: Definitions and Common Threads from Hooton to Mayr

Say the word race to ten different anthropologists and you might get ten different definitions. That is not because scientists were being sloppy. Between the 1920s and the 1960s, physical anthropologists and geneticists tried hard to pin down what race actually meant in biological terms, and each attempt reveals something about how the science of human variation was changing at the time.

Why anthropologists went looking for a working definition 🔗

In the early twentieth century, race was mostly described through visible traits: skull shape, skin colour, hair texture. But as genetics matured as a field, anthropologists realised that physical appearance alone told an incomplete story. Two people could look similar and still carry very different genes, or look different and share a recent common ancestor. This pushed scholars like Earnest Hooton, Theodosius Dobzhansky, William Boyd, Ernst Mayr, and Paul Baker to reframe race around descent, breeding populations, and gene flow rather than surface features alone.

Hooton and the idea of common descent 🔗

Earnest Hooton, writing in 1926 and refining his ideas through the 1940s, defined race as a group whose members share “individually identical combinations of specific physical characters” that they owe to a shared ancestry. In other words, race here is fundamentally about inheritance: a set of traits passed down through generations within a breeding population, later obscured by ordinary individual variation.

Hooton’s approach was still heavily morphological, focused on measurable physical traits rather than genes. It reflected the physical anthropology of his era, which relied on anthropometry and comparative anatomy. That approach came with serious baggage. Hooton’s own work was later criticised for reinforcing racial hierarchies and stereotypes rather than dismantling them, a reminder that even well-credentialed science of the period was shaped by the social prejudices of its time.

Dobzhansky and Boyd: race as gene frequencies 🔗

Theodosius Dobzhansky, a geneticist central to the modern evolutionary synthesis, pushed the definition in a very different direction. Rather than fixed types, he described races as populations differing in the incidence of certain genes, populations that were still capable of exchanging genes wherever their geographic boundaries met. This was a genuinely important shift: race stopped being a rigid box and became a statistical pattern, a difference in how often certain gene variants show up in one group compared to another. Dobzhansky was also clear that where exactly to draw lines between populations was a matter of convenience for researchers, not an objective fact about nature.

William Boyd, working with blood group genetics in 1950, arrived at a similar place from a different angle. He defined race as a population that differs meaningfully from other human populations in the frequency of one or more of the genes it possesses. Boyd’s work on ABO and other blood group systems gave this genetic view real empirical backing, since blood type frequencies could actually be measured and compared across populations without relying on subjective visual judgement.

Why the shift to genetics mattered 🔗

Moving from visible traits to gene frequencies changed what counted as evidence. A researcher no longer needed to measure skulls or classify skin tones by eye. Instead, they could compare allele frequencies between groups, a method far less vulnerable to the observer’s own biases, even if it still carried the risk of drawing arbitrary boundaries around continuous human variation.

Mayr’s subspecies model and Baker’s genetic distance 🔗

Ernst Mayr, one of the towering figures of twentieth-century evolutionary biology, approached race through the lens of taxonomy. He linked race to the concept of subspecies, describing it as an aggregate of phenotypically similar populations of a species occupying a particular geographic slice of that species’ overall range. This borrowed directly from how biologists classify subspecies in other animals, treating human races as one example of a broader biological pattern rather than something uniquely human.

Paul Baker took a more practical, operational route in 1967. He proposed that race be understood simply as a rough measure of genetic distance in human populations. This definition treated race less as a real, discoverable category and more as a convenient tool: a way of summarising how genetically similar or different two populations happen to be, useful for research purposes without claiming to capture some deeper biological truth.

What ties these definitions together 🔗

Despite coming from morphology, genetics, and taxonomy respectively, these definitions share two recurring threads. The first is geography. Every one of these scholars linked race to populations occupying particular regions, whether through Hooton’s common descent, Mayr’s geographic subdivisions, or Dobzhansky’s boundaries separating gene pools. The second is shared ancestry expressed through genes or traits passed down within a population.

Breeding populations, not fixed boxes 🔗

None of these definitions describe races as sealed, unchanging categories. Dobzhansky was explicit that populations were potentially able to exchange genes across whatever boundaries separated them, and Mayr’s subspecies model assumes ongoing gene flow between neighbouring groups. This is a crucial point that often gets lost in everyday usage of the word race: scientifically, these were always meant to describe dynamic, interbreeding populations, not permanent, closed-off human types.

The word race carries a heavier history 🔗

It helps to remember that race was never a neutral scientific term waiting to be discovered. The concept, as used in the way we recognise it today, took shape in eighteenth-century Western science and colonial societies, where it was used to sort and rank people rather than simply describe biological variation. Naturalists of the period built taxonomies that placed European populations at the top of an imagined hierarchy, a framework that then travelled with colonial expansion and the transatlantic slave trade to justify conquest and forced labour.

This history matters for understanding why the mid-twentieth century definitions from Hooton to Baker read the way they do. Scholars of that era were working to make race a more rigorous, measurable scientific category, partly in reaction to the crude typological racism of earlier centuries. As the Open Encyclopedia of Anthropology notes, the concept of race functioned as something of a master idea in anthropology for centuries, one that grew directly out of colonialism and continued shaping the field long after.

Where the science stands today 🔗

Modern biological anthropology has moved past treating race as a valid biological classification for humans. The 2019 statement from the American Association of Biological Anthropologists concludes that race does not accurately represent human biological variation, noting that humans share the overwhelming majority of their DNA and that genetic variation tends to change gradually across geography rather than falling into distinct, separate clusters. This is often called clinal variation, and it explains why any line drawn between one race and the next always ends up somewhat arbitrary, no matter which of the mid-century definitions you apply.

None of this erases the earlier debates covered here. Hooton, Dobzhansky, Boyd, Mayr, and Baker were each grappling seriously with a genuine scientific puzzle: how to describe human biological diversity in a rigorous way. Their disagreements, and the eventual move away from race as a biological category altogether, trace the actual path anthropology took from typology to population genetics to the more nuanced view of human variation held today. Understanding this history also makes it easier to separate the scientific study of human biological variation from race as a social category, which continues to shape lived experience even though it lacks a stable biological foundation, as documented by resources like Race: The Power of an Illusion.

What do you think? Given that Dobzhansky and Mayr both described races as populations still capable of exchanging genes across boundaries, why do you think the idea of race as fixed, separate categories persisted so strongly in public thinking? And does knowing the colonial origins of the term change how you read these mid-century scientific definitions?

References

1. https://egyankosh.ac.in/bitstream/123456789/41420/1/Unit-4.pdf
2. https://www.sciencedirect.com/science/article/abs/pii/S0306987709005374
3. https://onlinelibrary.wiley.com/doi/10.1002/ajpa.23882
4. https://www.britannica.com/topic/race-human/The-history-of-the-idea-of-race
5. https://www.anthroencyclopedia.com/entry/race-and-racism
6. https://www.racepowerofanillusion.org/articles/origin-idea-race/