Race Definitions in Anthropology: Key Concepts by Dobzhansky, Hulse, Garn, Hooton, Brue and Mayr

Ask five anthropologists to define “race” and you may get five different answers. That is not a sign of academic confusion. It reflects how differently scientists have approached the same puzzle: why do human populations look and vary the way they do, and where should we draw the lines between groups, if at all? Over the twentieth century, biologists and physical anthropologists proposed several competing definitions of race, each shaped by the science of its time. Understanding these definitions, from Dobzhansky’s genetic framing to Mayr’s subspecies model, helps explain why “race” remains one of the most debated concepts in the discipline.

Why anthropology needed a working definition of race 🔗

Early attempts to classify humans relied heavily on visible traits such as skin colour, hair texture, and skull shape. By the mid-1900s, advances in genetics forced anthropologists to reconsider these older, purely descriptive categories. Theodosius Dobzhansky, one of the architects of the modern evolutionary synthesis, is a good example of this shift. His own definition of race changed considerably between the 1930s and 1950s, moving from loosely described “clusters” of physical types to precise, genetically distinct populations, showing how the very concept was still being worked out in real time.

Dobzhansky’s genetic definition of race 🔗

In 1944, Dobzhansky proposed that races were populations that differed in the incidence of certain genes while still being able to exchange, or potentially exchange, genes across whatever geographic boundaries separated them. This was a significant departure from earlier typological thinking. Instead of treating races as fixed, unchanging “types,” Dobzhansky treated them as dynamic, interbreeding populations connected by gene flow.

Two implications followed directly from this framing. First, racial differences were treated as objectively measurable biological facts rather than subjective impressions. Second, and just as important, the number of races anthropologists chose to recognise was described as a matter of scientific convenience rather than a fixed natural number. Because no two human populations share identical gene frequencies, this definition blurs into the broader concept of a population itself, which is part of why later scientists found it both useful and frustratingly elastic.

Hulse and Garn: race as a breeding population 🔗

A related but distinct line of thinking came from Frederick Hulse and Stanley Garn, who anchored race more firmly in reproductive patterns rather than gene frequency alone.

Hulse’s genetic distinguishability 🔗

Hulse, writing in 1963, argued that races were populations that could be readily told apart from one another purely on genetic grounds. This kept the emphasis on measurable biological difference, but shifted the practical test from “do gene frequencies differ” to “can we reliably distinguish these groups genetically.”

Garn’s reproductive isolation angle 🔗

Garn’s 1960 definition added a crucial mechanism: a race, in his view, was a breeding population that was largely, though not always completely, reproductively isolated from other breeding populations. He was careful to note that this isolation usually arose from geography but was not limited to it; social, cultural, or linguistic barriers could produce similar effects. This is a point that resonates strongly in the Indian context, where endogamy and caste-based marriage practices have historically functioned as non-geographic barriers to gene flow, shaping the genetic structure of populations quite apart from physical distance.

Hooton’s morphological and metrical features definition 🔗

Earnest A. Hooton took a different route in 1926, well before population genetics reshaped the field. He described race as a great division of mankind whose members, despite individual variation, could be grouped by a shared combination of morphological and metrical features. Crucially, Hooton specified that these features were principally non-adaptive, meaning they were not necessarily the product of environmental pressure but were instead inherited from common ancestry.

This distinction between adaptive and non-adaptive traits mattered a great deal to Hooton’s methodology. Skin colour, for instance, is strongly shaped by exposure to ultraviolet radiation and therefore adaptive. Features like certain nose shapes or cranial proportions were, in his view, less tied to immediate survival advantage and more useful as markers of shared descent. Hooton’s approach relied heavily on physical measurement, particularly of the skull and face, to sort populations into broad categories such as Caucasoid, Mongoloid, and Negroid, along with numerous composite subgroups.

Brues’ hereditary traits and geographic association 🔗

Alice Brues offered a somewhat more flexible definition in 1977. She described race as a division of a species that differs from other divisions in the frequency with which certain hereditary traits appear, including features of external appearance that allow visual recognition of group membership. Members of a given race, in her framing, share ancestry with one another to a greater degree than with members of other races, and are usually, though not always, associated with a particular geographic region.

What makes Brues’ definition notable is its acknowledgment of degree rather than absolute boundaries. She did not claim that racial groups were perfectly isolated or perfectly distinct. Instead, she framed race as a matter of relative frequency and relative shared ancestry, a more statistical and less rigid way of thinking about human variation compared to Hooton’s earlier typological model.

Mayr’s subspecies classification 🔗

Ernst Mayr, a leading evolutionary biologist, approached the question from taxonomy rather than anthropology proper. He proposed that the major divisions of humankind be treated as subspecies: aggregations of local populations inhabiting a particular geographic subdivision of a species’ range, differing taxonomically from other populations of that same species. Mayr described a subspecies, or geographic race, as a group of similar populations occupying a distinct part of a species’ range and sufficiently different to warrant a separate name.

Mayr’s contribution went beyond simply relabelling races as subspecies. He explicitly argued that the factors responsible for differentiating human ethnic groups were both biological and cultural, insisting that humans needed to be studied as bio-social creatures rather than through biology alone. This was an unusually integrative position for its time, acknowledging that language, custom, and social organisation could shape human population structure just as much as genetics or geography.

Where these definitions agree, and where they break down 🔗

Despite their differences, these six definitions share a common thread: each treats race as a population-level phenomenon rather than a fixed set of individual “types.” Dobzhansky, Hulse, and Garn lean on genetics and breeding patterns. Hooton leans on measurable physical form. Brues blends physical appearance with degree of shared ancestry. Mayr borrows the language of taxonomy to place humans alongside other species that show geographic variation.

The trouble is that none of these frameworks map neatly onto how human genetic variation actually behaves. Later research in population genetics showed that most human traits vary gradually across geography rather than in sharp, bounded clusters, a pattern known as clinal variation. Populations living closer together tend to be more closely related than those living farther apart, with no natural line separating one group from the next. This is precisely why later scholars, working from the same body of Mendelian population thinking that Dobzhansky helped establish, gradually shifted anthropology’s vocabulary away from “race” toward “population” and “ancestry,” terms that better capture gradual, overlapping variation rather than discrete categories.

This does not mean human biological variation is imaginary. Skin pigmentation, disease resistance, and other traits genuinely differ in frequency across populations, and studying these patterns remains central to biological anthropology. Even Dobzhansky’s own definitions shifted repeatedly over two decades as he tried to reconcile the biological reality of population difference with the difficulty of drawing firm boundaries between groups. What has changed is the recognition that the boundaries between “races” are drawn by convention and convenience, exactly as Dobzhansky himself acknowledged, rather than discovered as fixed features of nature.

Why these definitions still matter for students of anthropology 🔗

Studying these six definitions is not just a historical exercise. Each one represents a distinct methodological approach: genetic frequency, breeding isolation, physical measurement, hereditary trait clustering, and taxonomic subspecies classification. Recognising these approaches helps students critically evaluate how racial categories have been used, and sometimes misused, in scientific, social, and administrative contexts, including within India’s own complex history of caste, tribe, and ethnic classification during and after the colonial period.

What do you think? If human genetic variation is largely clinal rather than clustered into distinct groups, what practical value, if any, do you think definitions like Garn’s or Mayr’s still hold for anthropologists today? And considering India’s own patterns of endogamy and regional isolation, does Garn’s idea of reproductive isolation without geographic separation change how you’d think about population structure closer home?

References

1. https://www.nature.com/articles/424374a
2. https://egyankosh.ac.in/bitstream/123456789/90333/1/Unit-13.pdf
3. https://egyankosh.ac.in/bitstream/123456789/73689/1/Unit-7.pdf
4. https://www.amacad.org/publication/daedalus/biology-race
5. https://skepticalinquirer.org/2016/05/biological-race-and-the-problem-of-human-diversity/
6. https://pubmed.ncbi.nlm.nih.gov/23706915/