Head Shape Variation & Plasticity

Human Skulls

While individuals differ, biological differences between races are small. There is no reason to believe that one race is by nature so much more intelligent, endowed with great will power, or emotionally more stable than another, that the difference would materially influence its culture.
–Franz Boas, Race and Progress (1931:6; See endnote #1)

As discussed in the previous section on Biological Anthropology and Racism, the issue of race is a core part of the history of anthropology. Anthropologists studied human nature and human difference, born as a scientific study of Savages and Human Nature. However, over a century ago, Franz Boas began championing an anti-racist position as he became a prominent founder of academic anthropology. Boasian Anthropology should have won the battle on race by the 1930s.[See endnote #2]

Boas’s research disproved deterministic connections between biology and behavior. Far ahead of his time, Boas revealed how motor movements–ways of walking, dancing, posing, smiling–are part of our learned behavior. They are learned so intimately and thoroughly that they feel natural. Since we learn motor movements, people of different physical appearance can learn them. The Boasian approach became a bestseller for Ruth Benedict’s 1934 Patterns of Culture.

Franz Boas, Measuring Bodies & Heads

In addition to exploding the supposed connection between race and culture, Boas measured the head shape of immigrants and their children in New York City. This work on human skulls challenged the physical basis of human racial categorization. Measuring heads of people from central and southern Europe, Boas determined that within one generation of arrival there were already measurable changes in human skulls and body form. Environmental factors like nutrition and hygiene played a larger role than anyone had realized. Contrary to popular belief, this was not always a change in a positive direction. Sicilians became more physically stunted in the new environment. Boas was himself an immigrant. His work also helped shape later anthropological statements on immigration.

Many people found Boas’s study outrageous, dismissing it from the beginning. In the early 2000s, some anthropologists returned to the data on human skulls and claimed Boas got it wrong. Another group of anthropologists re-examined the data and said Boas got it mostly right:

As Boas hypothesized, our results show that children born in the U.S. environment are markedly less similar to their parents in terms of head form than foreign-born children are to theirs. . . . This finding thus corroborates Boas’s overarching conclusion that the cephalic index is sensitive to environmental influences and, therefore, does not serve as a valid marker of racial phylogeny. (Gravlee, Bernard, and Leonard 2003:135; also see Gravlee’s Franz Boas’s Immigrant Study Bibliography, with references through 2004).

Others say there is some room for variation based on nutrition and climate, but cranial form can still be used for exploring genetic questions (Relethford 2004). For more extensive discussion, especially about the use of computer programs in classification, see On the misclassification of human crania (Hubbe and Neves 2007).

Apart from the back-and-forth within the number-crunching community, the larger picture is clear:

Human head shape is considerably plastic.

Environment and cultural practices play an enormous role in shaping our heads. Certainly genes regulate the unfolding process of development and growth of human skulls. And those skilled in the use of calipers can use particular features of human skulls as a proxy for understanding ancestry and inherited genes. However, genes do not determine the shape of human skulls. That shape is the dynamic result of developmental systems.

Three Cases of Variation in Human Skulls

  1. Many ancient societies practiced rather severe forms of cranial manipulation, mostly absent from contemporary societies. So much for ancient societies as a natural baseline! Interestingly, neurosurgeons report “there does not seem to be any obvious evidence of negative [cognitive] effect on the societies that have practiced even very severe forms of intentional cranial deformation” (Lekovic et al. 2007:1137).
  2. In contemporary societies with cribs and back-to-sleep campaigns, infants may need to get “helmet treatment” to keep their head shape round. Excessive use of cribs, bouncy chairs, and car seats can result in flat-headed folk. We now have to educate parents to teach their infants how to turn their heads. In other words, infants allowed to follow their natural path can end up with quite unnatural head shape.[See endnote #3]
  3. Researchers have determined that deliberate infant head molding, although not practiced in its extreme form, is still widespread:

    Our data lead us to question the validity of using skull shape for racial or ethnic classifications or both. Historically and currently, the ubiquitousness of infant head molding that resulted in various head shapes, even those that might not necessarily be identified as deformed, suggests that labeling crania as typical or atypical for certain groups is incorrect. Further, we suspect that, in many instances, the genetic traits so often described by physical anthropologists . . . may well be the unrecognized result of manual manipulation of the infants’ cranial bones. (Infant head molding: a cultural practice, FitzSimmons et al. 1998:90)

Another surprise is that Richard Jantz, one of the original re-examiners of the Boas data who again reappraised the findings:

Change in Hebrew cranial indices resulted from abandoning the practice of cradling infants in America. U.S.-born Sicilian children experienced an environment worse than the one in Europe, and consequently experienced impaired growth. We conclude that the changes Boas observed resulted from specific behavioral and economic conditions unique to each group. (Jantz and Logan 2010:702)

To be sure, Jantz and Logan still write that “re-examination of Boas’s immigrant data has shown that Boas overstated the magnitude of the changes, which were actually small compared to variation among ethnic groups” (2010:703). Nevertheless, in 2012, Jantz is again at the forefront of discovering recent changes in head form: Americans’ Heads Getting Bigger.

It comes back to a central idea about human nature:

There is no such thing as a natural--or genetically determined--head shape.Click To Tweet
Of course, to echo Tim Ingold’s words about human nature–see Human Nature and Anthropology–human head shape is not anything we please. But we cannot describe our heads outside of the particular historical and environmental circumstances in which we grow.

Human Skulls: Measuring what we expect to see

In a fascinating 2016 research article, The vanishing Black Indian: Revisiting craniometry and historic collections, Pamela Geller and Christopher Stojanowksi show how much our measurements are influenced by what we think we’ll find. Or what we imagine race was like in the past.

Recent articles discussing the merits and weaknesses of comparative craniometry focus on methodological issues. In our biohistoric approach, we use the patterning of craniometric allocations across databases as a platform for discussing social race and its development during the 19th century, a process known as racialization. Here we propose that differences in repeatability for the Seminoles and Euro-American soldiers reflect this process and transformation of racialized identities during 19th century U.S. nation-building. In particular, notions of whiteness were and remain tightly controlled, while other racial categorizations were affected by legal, social, and political contexts that resulted in hybridity in lieu of boundedness.

Which is a great way to begin the next section on the Race Revival. Put differently, the acknowledgement of hybridity and diversity that was well underway in anthropology got interrupted and challenged by a racist renaissance.

Next: 1.5 – Race Revival
Previous: 1.3 – Biological Anthropology and Racism

Endnotes (click note number to return to text)

Note #1. To discuss these issues for Introduction to Anthropology, I use Our Babies, Ourselves by Meredith Small. In Cultural Anthropology, I have used an excellent two-page overview Franz Boas and Anti-Racist Education (Burkholder 2006). The 1980 PBS Odyssey film simply titled Franz Boas is also interesting. The PBS film attempted “to cut the often esoteric ice of anthropology.” For contemporary viewers the film is itself often like esoteric ice.

Note #2. Eugenia Shanklin’s article The Profession of the Color Blind: Sociocultural Anthropology and Racism in the 21st Century urged anthropologists to become more active on the question of race. For Shanklin, the Boas victory only meant “American anthropology won the battle and lost the war” (1998:670). Shanklin took her own message to heart, publishing an undergraduate textbook titled Anthropology and Race: The Explanation of Differences. We sadly lost Eugenia Shanklin in 2007. Her textbook deserves to be updated.

Note #3. See Tummy Time is Important (Graham 2006) or Tummy Time: Why babies need more of it than they’re getting (Mossop 2010). With pediatricians saying “atypical skull shapes occur in as many as 20% of infants” (Cunningham and Heike 2007:645) it leads to questions of how the typical skull shape became normalized. Some pediatricians are calling attention to contemporary changes, going so far as to consider “that the percentile growth curves used for plotting head circumference may not be reliable for this new back sleeping population” (Pomatto et al. 2006:62).

To cite: Antrosio, Jason, 2011. “Human Skulls: Anthropology on Head Shape Variation and Plasticity.” Living Anthropologically website, https://www.livinganthropologically.com/biological-anthropology/human-skulls-boas-head-shape/. First posted 6 June 2011. Revised 6 October 2017.

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  • Jon Marks

    Do you think there is something vaguely Oedipal about people who want to kill and replace Boas as the father of American academic anthropology?

  • Jamie Jensen

    “Boas worked to sever a deterministic connection between biology and behavior”

    There you have it folks. Political motivation masquerading as “science” to arive at his conclusions apriori. More like scientology, this Boaz was jewish and had an agenda against European anthropology which relied on true scientific methods with often politically incorrect results.

    • I probably should have worded it more like this: Boas used scientific evidence to demonstrate that there was no deterministic connection between biology and behavior. Amazing that after 100 years, Boas-on-race still makes people angry, although see this recent re-assessment of Boas on race and racism for more on what Boas and his students:

      As Lee Baker has shown, Boas had some serious limitations in his own era, and they loom even larger in today’s context. In their own time Boasians ignored the political economy of race and the sociocultural organization of African American communities. Political and economic oppression of black Americans was the “self-evident” confirmation of white supremacy. With 20-20 hindsight it’s easy to see how big that omission was. Nevertheless, the political economy of American racism was very much part of the analysis of progressive scholarship in Boas’ time. W.E.B. DuBois, whom Boas knew and worked with, and anthropologists like Alison Davis, St. Clair Drake and Horace Cayton, contemporaries of Boas’ students, were publishing politically and economically-informed analyses of Black America and of African American cultural communities. (Karen Brodkin, via interview by Ryan Anderson)

      • meliorist

        The idea of genetic determinism is a straw man. You’d struggle to find any scientist who believes that genes strictly determine quantitative phenotypic traits.

        On the other hand, Boas seems to have been an environmental determinist – that is to say, he appears to have argued, or at least sought to suggest, that all variance among human beings (between groups, at any rate) is due to environmental factors, and none at all can possibly be due to genetic factors. It’s an implausible position, given that genes affect pretty much everything in all organisms, and proving that environmental factors affect skull dimensions is not the same thing as proving that genetic factors don’t.

        • No, I believe you are the one superficially reading Boas and creating the straw man of environmental determinism.

          • Hobbesian Meliorist

            Environmental determinism is very far from being a straw man. Consider “Not in Our Genes”, 1985, co-authored by Steven Rose, Leon J. Kamin and R.C.Lewontin (all avowed Marxists), in which they argued that genes have zero to negligible effect on human individual or group differences in psychological traits, ergo, all differences are determined entirely by environmental factors. Richard Dawkins famously reviewed the book as “silly, pretentious, obscurantist and mendacious”.

            Consider “Behaviorism”, by John B. Watson, in which he proclaimed boldly that, given any child in infancy, he could mold that child into any kind of adult, using the methods of behavioural conditioning. This was explicit environmental determinism, and it was highly influential. The term “conditioning” is still constantly used to imply an environmental determinist position. For instance, feminists claim that differences between the sexes are entirely caused by conditioning. (The phrases “environmental conditioning” and “social conditioning” are both used.) In this, they echo not just J. B. Watson, but Mary Wollstonecraft, who, influenced by Locke’s associationist ideas that were popular in the 18th century, made a similar claim in her “Vindication of the Rights of Woman.”

            Consider that Stalin promoted Lysenko to the top of the Soviet Union’s agricultural research body and enabled Lysenko to fire all the geneticists and send them into internal exile. Why did this happen? Because Lysenko’s crackpot environmentalist ideas (essentially Lamarckism) were politically correct, whereas the ideas of the geneticists were “bourgeois”. Particularly abhorrent to Stalin was the idea that some people might have better character or more intelligence than others due to their genetic inheritance.

            Since most Leftist parties around the world took orders at the time, directly or indirectly, from the Soviet Union’s Politburo, they all fell in line. In Britain, even J B S Haldane, the eminent geneticist, who was a Marxist in his spare time, fell in line, and published a defense of Lysenko. He didn’t go quite so far as to say plainly that Lysenko was correct, but he didn’t need to, since George Bernard Shaw, prominent Fabian Socialist and world-famous, Nobel-prize-winning playwright and essayist, published an essay in a Labour Party journal saying outright that not only was Lysenko right, but Darwin was wrong, and August Weisman’s ideas (which, along with Mendel’s, are foundational ideas of modern genetics) were pseudoscience. The left has traditionally been committed to environmentalism.

            On YouTube, you can find a debate between James R. Flynn and Charles Murray concerning racial IQ differences. I think it’s about an hour or ninety minutes, but they argue each other to a standstill. Murray admits that he can’t prove conclusively that the differences are to some extent genetic, though he thinks the evidence points that way, but says that, regardless of whether they’re genetic or not, they are persistent and pervasive, and seem to be very difficult to change. Flynn admits that he can’t prove that the differences are all environmental, but he continues to think that he continues to think so. Flynn’s position for decades has been that group differences in intelligence are environmental, and the part played by genes in group (but not necessarily individual) differences, is negligible.

            On top of all that, there are countless sociological works which implicitly assume that environment is the sole determining factor in differences in personality, ability, etc. You must have seen studies in which things along the following lines, for instance, are said: “children do well in school who have parents who read to them in bed, have books in the house, and take them to museums… we conclude that these parental behaviors cause to children doing well in school, and if only we could change the domestic environment of the other children, they too would do well in school.” Such studies tacitly assume that genetic factors are not relevant, since no attempt is made to empirically rule out the possibility that the environmental variable is confounded by a genetic factor.

          • weknow

            yes. the idea that genetics plays no role in our behavior is just pure pseudoscience.

      • Hobbesian Meliorist

        There’s another giveaway in your article, down in the footnotes, where you write that ‘Eugenia Shanklin’s article The Profession of the Color Blind: Sociocultural Anthropology and Racism in the 21st Century
        urged anthropologists to become much more active on the question of
        race, since the Boas victory only meant “American anthropology won the
        battle and lost the war” (1998:670).’

        If anthropologists see themselves as being engaged in a “war” against racism, then it is likely that they will not look at possible evidence of racial differences with scientific detachment and impartiality.

    • Die kil Sergeant

      Thank you Jamie Jensen! You are the living proof of the incompetentness some so called white supremacy have by only acknowledging the technological development of the world through historical changes and even there the asians overclass the whites even as we refer to the classical cranial studies. When you look at the social development, the many limited thinking white people like yourself are founding yourself at the bottom while the Rest of the world ( your forefathers ( black people)) are at the top of this social development. So while you try to convince yourself that Boas had a hidden agenda maybe you find your own if the social area in your own cranial allows you to.

  • Anonymous

    There are no non-aboriginal skulls that look like the left. It doesn’t look like that because it’s malformed. You are an idiot.