Anthropological Wokeism tries to stymie research

July 19, 2022 • 1:15 pm

This article about conflicts in anthropology involving gender and ethnicity comes from the website of Jonathan Turley, whose name I’d heard before but whose work and politics I didn’t know. His Wikipedia bio doesn’t give much clue into his politics (to be truthful, I didn’t look hard for it, since it seemed irrelevant to the story), I wondered simply because he cites a right-wing website below.

But Turley is no weirdo: here’s one bit from his Wikipedia bio:

Turley holds the Shapiro Chair for Public Interest Law at The George Washington University Law School, where he teaches torts, criminal procedure, and constitutional law. He is the youngest person to receive an academic chair in the school’s history. He runs the Project for Older Prisoners (POP), the Environmental Law Clinic, and the Environmental Legislation Project.

I am assuming, then, that what he describes and quotes is accurate, and will give my views accordingly.  Here’s the article at hand, which relates to the last article we had about ethnicity (which, of course, reflects ancestry). Click screenshot to read:

I’ll be brief: there is a cadre of anthropologists who want to stop their colleagues from classifying skeletons by sex and by trying to find out their ancestry. The reason? Because it doesn’t comport with today’s “progressive” Leftist views. I’ll quote Turley:

There is an interesting controversy brewing in anthropology departments where professors have called for researchers to stop identifying ancient human remains by biological gender because they cannot gauge how a person identified at that the time. Other scholars are calling for researchers to stop identifying race as a practice because it fuels white supremacy.  One of the academics objecting to this effort to stop gender identifications, San Jose State archaeology Professor Elizabeth Weiss, is currently suing her school. Weiss maintains that she was barred from access to the human remains collection due to her opposition to the repatriation of human remains. The school objected that she posted a picture holding a skull from the collection on social media, expressing how she was “so happy to be back with some old friends.”

The conservative site College Fix quotes various academics in challenging the identification of gender and notes the campaign of the Trans Doe Task Force to “explore ways in which current standards in forensic human identification do a disservice to people who do not clearly fit the gender binary.”

Let’s take sex and ancestry separately. Turley’s prose is indented.

On gender and sex:

University of Kansas Associate Professor Jennifer Raff argued in a paper, “Origin: A Genetic History of the Americas,”  that there are “no neat divisions between physically or genetically ‘male’ or ‘female’ individuals.”  Her best selling book has been featured on various news outlets like MSNBC.

. . . However, Raff is not alone. Graduate students like Emma Palladino have objected  that “the archaeologists who find your bones one day will assign you the same gender as you had at birth, so regardless of whether you transition, you can’t escape your assigned sex.”

Well, given that sex is pretty close to a complete binary in humans, and is reflected and diagnosable in our bones bones—hence “Lucy“, A. afarensis, was female and “Turkana Boy“, H. ergaster was male—you determine biological sex from skeletons, not gender.

Is that a problem? I don’t see how. Even if our hominin relatives or ancestors did have concepts of gender beyond male and female, there are genuine scientific questions to be answered by studying biological sex from ancient remains.  What was the ratio of males to females in various places, and if it differed much from 50:50, why? If someone’s remains are associated with items, like Ötzi the hunter (actually a mummy), one can conclude something about ancient cultures and the possibility of differential sex roles. Is it important for scientists to debate whether Ötzi identified himself as a “they/them” given that we’ll never know the answer? Or are we forbidden to inspect the genitals? (He was a biological male).

Now it is of sociological value to determine whether our ancestors identified as “men and women” and saw only two genders, but if we can’t do that, it’s ludicrous to say that we shouldn’t identify remains on the basis of biological sex—a lot easier to do! I won’t give a list of scientific questions that can be addressed by knowing the sex of a fossil hominin, but there are lots, and yet some anthropologists want to stop all such research because hominins may not have had gender roles that matched their biological sex.

On ancestry and ethnicity:

Likewise for ancestry. It’s sometimes possible to guess one’s ethnicity from skeletal morphology, but it’s much more accurate to do DNA sequencing. (Sequencing of fossil DNA can tell us both biological sex and which group of either ancient or modern humans you most resemble genetically.) Yet some anthropologists want to stop that research, too. Turley:

Professors Elizabeth DiGangi of Binghamton University and Jonathan Bethard of the University of South Florida have also challenged the use of racial classifications in a study, objecting that “[a]ncestry estimation contributes to white supremacy.”  The authors write that “we use critical race theory to interrogate the approaches utilized to estimate ancestry to include a critique of the continued use of morphoscopic traits, and we assert that the practice of ancestry estimation contributes to white supremacy.”

The professors refer to the practice as “dangerous” and wrote in a letter to the editor that such practices must be changed in light of recent racial justice concerns.

“Between the devastating COVID-19 pandemic and the homicides of numerous Black Americans at the hands of law enforcement officials, we have all been reminded about the fragility of life, and the failures of our society to live up to the ideals enshrined in the foundational documents which established the United States of America over two centuries ago. Tackling these failures seems overwhelming at times; however, changes can be enacted with candid and reflexive discussions about the status quo. In writing this letter, we direct our comments to the forensic anthropology community in the United States in hopes of sparking a discussion about the long-standing practice of ancestry estimation and changes that are frankly long overdue.”

Once again, research is supposed to be squelched for ideological reasons. Yet estimating ancestry of remains can answer lots of interesting questions.  One, for example involves DNA sequencing of Neanderthals and modern humans. I would consider these to be different, long-diverged ethnic groups of a single species, not different species, for they could interbreed where they lived in the same area and also produce fertile hybrids.

That’s just a guess, but without sequencing their DNA, we wouldn’t know not only that they hybridized, but also that many of us still carry some ancient DNA from Neanderthals.  Where did the Denisovans belong? (We don’t know whether they were a different species of hominin from modern humans or simply an “ethnic group.”) What about H. erectus? Did they die out without issue, or are they related to any modern populations?  Do any of their genes still hang around in H. sapiens? (I don’t think we’ll answer these questions.)

It is the sequencing of DNA of people from different geographic areas (“races” if you will, but call them whatever you want) that has helped us unravel the story of human migration, how many times we left Africa and when, and when different groups established themselves in places like Australia and Polynesia, or crossed the Bering Strait into North America. DNA and estimation of ancestry has immensely enriched the story of human evolution and migration. That’s all from “ancestry estimation”, and you don’t even need a concept of “race” to answer these questions—only a concept of “ancestry” and “relatedness”. Nor does this research contribute to white supremacy, though of course some racists may coopt it.

In the interests of woke ideology, in other words, some anthropologists want to shut down two promising lines of research. I call that misguided and, indeed, crazy. If you despise white supremacy like most of us do, you don’t get rid of it it by banning anthropological genetics. If you want sympathy for people whose gender doesn’t match their biological sex, you don’t get it by stopping researchers from determining the biological sex of ancient human remains.

As the Wicked Witch of the West said, “Oh, what a world! What a world!”

Two questions about human history

December 26, 2021 • 9:30 am

I’m sure that historians have pondered the first question at length, but I haven’t read their lucubrations. According to Wikipedia, the first definitive use of the wheel on transportation was in Mesopotamia around 3500 B.C. We don’t know how many times it was invented independently, but probably more than once (see below):

So, my first question is this: Why was the wheel not devised in the New World? The Americas had plenty of civilizations, including many Native American groups, and the Aztecs, Incas, and Maya as well as many other groups, but none of them had the wheel, with one exception (see below). Why? Further, the Diquis culture had stone spheres beginning about 300 A.D., so they certainly knew that something round could roll. But this wasn’t adapted for carts or other rolling entities. Yet the Incas are said to have used wooden rollers to roll large stones for their walls and cities. Why no wheels, then?

According to The Straight Dope (I just looked this up), there was one exception:

The wheel evidently was familiar to the ancient Mexicans, the only known instance of its having been invented independently of the Sumerian version. Unfortunately, it apparently never occurred to anyone at the time that wheels had any practical application, and their use was confined to little clay gadgets that are thought to be either toys or cult objects.

That link also gives you an explanation that Cecil Adams considers definitive, but I don’t know. See for yourself.  I am guessing that Jared Diamond pondered this question in Guns, Germs, and Steel but I read it so long ago I can’t recall. Go to the link, read “the” answer to my question above, and see if you agree with Cecil.

My second question is this:  How did our ancestors keep their fingernails and toenails at reasonable length?

I thought of this question while clipping my nails the other day, and thought, “Scissors and nail clippers, and even steel knives were not invented in fairly late in human history. But yet our ancestors did without them for millions of years.  How did they keep their nails short?

Now you might say, “They didn’t need to: their nails wore down from hunting, gathering, and walking barefoot.” But I am not sure this is the case. How would walking barefoot wear down your toenails? And we know that, at least in modern society, if you don’t trim your fingernails and toenails, they get ungodly long (see below).  Did the ancients use flint? And what did they do before they had flint implements? Or did they bite their fingernails?

Now we could surely answer this question by observing what hunter-gatherers do, if anything, to keep their nails short. But I am not going to look it up; I’d rather have readers speculate or, if they know the answer, tell me.

Below: a video showing what happens if you don’t trim your nails: here’s a man who didn’t trim the nails on one hand for 66 years. (He explains why.) He has, on that hand, the longest known fingernails in history.

Of course he had to cut his nails on his right hand so he could do stuff (and I’m betting he’s a rightie). Nobody would marry him, and you can imagine the trouble he had just living from day to day. It’s all in the video

At the end they cut his nails:


Fire use by hominins: an example of rapid cultural evolution?

July 26, 2021 • 9:15 am

Yesterday we discussed the possibility of cultural evolution (dissemination of a behavior or skill through imitation and learning) in cockatoos, which attracted a lot of attention, probably because of its parallel with human cultural evolution. (The cockatoos seem to have learned to open garbage bins by watching each other.) And in our species there are a gazillion examples, especially since transportation allowed innovations to be spread quickly and widely. You can think of lots of cases: blue jeans, cuisines from other places, music, and, earlier than that, printing, the wheel (some cultures never got it) and even religion.

The new paper in Proc. Nat. Acad. Sci. below, however, suggests what may have been the very first behavior that spread though species of Homo (not only H. sapiens, but perhaps Neanderthals, which some consider a different species) through movement of individuals: the use of fire.  Click on the screenshot to read the article (free) below, or get the pdf here. The reference is at the bottom.

Fire, of course, has many uses: besides cooking meat and tubers, it can be used to harden wood to make spear points, change the quality of stone to make it easier to flake, and to keep yourself warm. Other uses are given in the Wikipedia article “Control of fire by early humans.”

The MacDonald et al. paper collects evidence of fire use from species of Homo, concluding that it got started about 400,000 to 350,000 years ago and then spread rapidly throughout the species. The rapidity of spread then led them to propose what kind of social structure was present in humans at that time.  This contradicts speculations H. erectus controlled the use of fire about 1.5 million years ago; the authors find that evidence unconvincing.

The problem is to distinguish anthropogenic (“human caused”) fire from natural wildfires. But there are ways of doing this, as the article summarizes. Hearths and charred animal bones are one way. Here’s another bit of evidence: a fire-hardened wooden spear from, coincidentally, about 380,000-400,000 years old, part of a group of artifacts found in Germany:

I can’t evaluate the quality of the evidence, but the authors summarize a lot of data to conclude that regular fire use began about 400,000 years ago, and spread quickly throughout the Old World, with evidence coming from Portugal, Spain, France, Israel, and Morocco. Two quotes:

. . . a review by Roebroeks and Villa identified a clear pattern for Europe: there the record strongly suggests that anthropogenic fire use was very rare to nonexistent during the first half of the Middle Pleistocene, as exemplified by the absence—bar a few dispersed charcoal particles—of fire proxies in deeply stratified archaeological karstic sequences, such as the Atapuerca site complex in Spain or the Caune de l’Arago at Tautavel (France), as well as from such prolific open-air sites as Boxgrove in the United Kingdom. In contrast, the record from 400 ka onward is characterized by an increasing number of sites with multiple fire proxies (e.g., charcoal, heated lithics, charred bone, heat-altered sediments) within a primary archaeological context.

. . . The spatiotemporal pattern of the appearance in the archaeological record of an innovation provides evidence relevant for identifying how the innovation came to be widely distributed: that is, through independent innovation, demic processes, cultural diffusion, or genetic processes. The fact that regular fire use appeared relatively quickly across the Old World and in different hominin subpopulations strongly suggests that the behavior diffused or spread from a point of origin rather than that it was repeatedly and independently invented.

Since fire appeared in both warm and cold places around the same time, the authors suggest that its inception was not correlated with “environmental pressures” (e.g., cold). And because the spread was so rapid, the authors claim, correctly, that the spread throughout the Old World was very unlikely to have been caused by the diffusion of genes producing the tendency to create fire, which would spread only very slowly. Likewise, the near-simultaneity makes it seems unlikely that the use of fire was invented independently by several groups.

If fire use did spread through imitation and learning, then, what does that say about the social structure of early humans? If we were divided up into groups of xenophobic hunter-gatherers who didn’t interact, that would not facilitate the spread of fire. Why would a group give the skill to a competitor group? There are two alternatives.

The first, “demic diffusion,” is that a “deme” (a cohesive populations of hominins) spread rapidly, taking with it the fire use they invented. This seems unlikely given that the spread was more rapid than one could imagine a single population could migrate.

The alternative comprises groups that tolerated each other, and were at least somewhat friendly. As the authors suggest, there was a more “fluid social structure with multiple levels of clustering in social networks”. In other words, perhaps hominims were more interactive than we thought.

Well, we have no direct evidence for that, and it would be hard to come by. And I’ll let other physical anthropologists judge the “simultaneous spread” hypothesis. But I wanted to bring this up because the scenario is at least plausible, and it may be the first evidence for cultural evolution in our genus.

There’s one other trait they add in to the mix as another behavior that spread by cultural evolution: the “Levallois technology” for knapping stone (striking flakes off a stone like flint to make weapons and other implements). This, say the authors, can be learned only through “close and prolonged observation combined with active instruction.” Here’s the Levallois method, which involves producing a flint core in such a way that sharp flakes, useful for tools, can be easily struck off:

The authors posit that this technology also originated in one place, but about 100,000 years later than fire (and surely in a different place), and then spread rapidly among groups in a similar way: non-hostile group interactions in a multi-level social network.

I’ll close with the authors’ final paragraph, summarizing their views:

We hypothesize that around 400 ka, cultural processes supported change in technology across wide areas. This indicates, at a minimum, a degree of social tolerance for individuals from different groups, and suggests the less minimal but still plausible hypothesis that more intensive cooperative interactions within larger-scale networks were already in place, occasionally crossing the boundaries between what we usually infer to have been different biological populations within the wider hominin metapopulation. [JAC: I think they’re referring to movement between “modern H. sapiens and Neanderthals. After all, these groups did mate with each other] We conclude that the spatial and temporal pattern of the appearance of regular Middle Pleistocene fire use documented in the archaeological record signals more than the advent of an important tool in the hominin toolbox: the presence of cultural behavior more like that of humans today than of our great ape relatives. We suggest that long before the cultural florescence associated with the late MSA/Middle Pleistocene and to a greater extent LSA/Upper Paleolithic periods, hominins were beginning to develop the capacities for complexity, variability, and widespread diffusion of technology and behavior that we tend to associate only with H. sapiens.


MacDonald, K., F. Scherjon, E. van Veen, K. Vaesen, and W. Roebroeks. 2021. Middle Pleistocene fire use: The first signal of widespread cultural diffusion in human evolution. Proceedings of the National Academy of Sciences 118:e2101108118.

Faith versus fact: the problem of Native American creationism and paleoanthropology in North America

June 14, 2021 • 9:30 am

This article in Quillette caught my eye because it was about science—paleoanthropology—and its conflict with faith. The authors are a pair of anthropologists who have written a book about the topic, which is the perennial conflict between scientists on the one hand and Native Americans claiming ancient human remains that, they say, are their ancestors.

Click on the screenshot to read:

The title refers to a meeting of the SAA in April when Weiss gave a talk about the obstructionism of Native American creation myths as they affect paleoanthropology in North America. Although the talk is certainly germane, and provides food for thought (see below), it was in effect “erased” by the SAA, who refused to post it despite their pledge to do so. It was the only talk that wasn’t posted. The reason is clear: going up against the claims of Native Americans, even if those claims can’t be supported, is a no-win situation. As Weiss writes:

The new SAA president, Deborah Nichols, subsequently contacted me to let me know that the video of our live talk would not be posted by the SAA for others to view, due to reports of hurt feelings. (We had previously relied on the SAA’s emailed assurance to presenters that “sessions will be available for viewing on demand within 24–36 hours after their original broadcast, until July 17, 2021.”) Furthermore, we learned, the SAA would not even provide us with the video. (And so we re-recorded the talk, which you can find here.) Another SAA statement was then put out to inform readers that “the SAA board finds the presentation does not align with SAA’s values,” and mentioned that “the board categorically rejects the Weiss-Springer position.”

Here’s the 13-minute talk that Weiss re-recorded after the SAA refused to post it:

There was substantial other pushback on both professional and social media. Here’s an example of a reaction by an “indigenous archeologist” to Weiss’s abstract of the talk: archaeologist.”

Hurt feelings again!

Well, we all know about these conflicts, and it’s conceivable that for some of them the Native Americans have a right to the bones and artifacts found by archaeologists, who of course lose the chance to study them.  But in most cases that “right” is dubious, for the genetic connection between those claiming the bones and the person whose bones are claimed is tenuous at best. Often it rests solely on creation myths: many Native Americans claim that despite scientific evidence that the Americas were populated by “modern” H. sapiens who crossed the Bering Strait from Asia about 15,000 years ago, their ancestors have lived in America forever. Further, to establish that the bones belong to a specific tribe is almost impossible, because bones from people of multiple “tribes” have been found in one locality, and there was considerable migration within North and South America.

Genetic analysis could conceivably settle the question, but without the bones you don’t have the DNA, and even so it’s hard to narrow down ancient DNA to a specific existing group of Native Americans, who are fairly closely related to each other. It’s even worse because the U.S. government passed laws saying that establishing ancestral (i.e., genetic) affinity isn’t necessary: “cultural evidence”, like oral traditions and creation myths, is sufficient. That immediately puts science at loggerheads with superstitions, superstitions that can be demonstrably incorrect.

As an example, Weiss and Springer discuss the famous Kennewick Man, 8,400- year-old remains of a man found in 1996 in Kennewick, Washington. It’s one of the most complete ancient North American skeletons ever found (see photos at bottom), and dates pretty close to the time when Asians began populating the Americas. But the remains were claimed by several tribes of Native Americans, although, according to the authors “the oldest known American tribe, the Hopi, reliably dates its history to only about 2,000 years ago.”

This started a decade-long court case between Native Americans, scientists, and the U.S. Army Corps of Engineers.  The case wasn’t resolved until 2004, and in favor of the scientists, though the remains have since been returned to a “coalition of Pacific Basin tribes” for reburial.

In the meantime, scientific studies of the skeleton, including use of DNA, showed that it was actually more closely related to “modern American Indian populations of Central and South America who are not ‘Native American'” by the U.S. government’s regulations. Using ancestry rather than creation myths, those other populations would have a stronger claim to the bones than would North American tribes.

In the meantime, scientists were able to find out a great deal of information from the skeleton. As the article states,

The greatly delayed scientific study was finally carried out, and the result was a magnificent peer-reviewed 2014 volume, edited by Jantz and Douglas Owsley of the Smithsonian Institution, titled: Kennewick Man: The Scientific Investigation of an Ancient American Skeleton. The studies revealed Kennewick Man’s age, sex, bone morphology, and bone chemistry, as well as modifications to the skeleton incurred during his life. This information, in turn, allowed inferences as to his food intake, food production, and other physical activities, and diseases and injuries he’d endured.

His affinities with other prehistoric and modern populations and individuals were also revealed by these studies. Kennewick Man’s dietary reconstruction from nitrogen isotopes (elements found in a variety of food sources that settle in bones and teeth, and which can be used to reconstruct eating and weaning patterns) revealed a diet composed mainly of marine foods. This differed from the previous view of Paleoindians as big game hunters. Kennewick Man also had bony growths in his ear canals called external auditory exostoses, which some have argued may have impacted his hearing and were related to chronic ear infections.

Kennewick Man had multiple injuries—including a projectile point (a spear head) in his pelvic bone. Chatters argued that this injury never healed properly and likely caused lifelong pain. Anthropologist Della Cook, on the other hand, suggested that the lack of reactive bone (which is evidence of bone healing from injury or infection) in the CT-scans suggests that Kennewick Man’s injury healed quickly. Interestingly, these two perspectives were both published in this 2014 book—an example of the open-minded manner in which science should be conducted and evaluated.

All of this information would have been lost had the repatriationists been successful. No other Paleoindian is as well studied as Kennewick Man, and many were reburied with just a simple osteological report. Such reports may include only the remains’ antiquity, sex, estimated age, and other basic information; and often are written up by undertrained students and marginal scholars who are not subject to peer review, and who do not report their findings in a way that contemporaries can validate. . .

Weiss and Springer describe other cases in which cultural tradition blocked scientific study, as well as scientific study that did succeed in finding out stuff about early Native Americans.

So what should the rule be? Of course, as a scientist who values scientific fact over creation myths or oral tradition, I’m biased in favor of empirical study. But if remains can be traced to a specific tribe or group of tribes, showing the bones to be more closely related to that group than to other tribes, one might consider tribal claims to be valid.  Even so, perhaps there should be an allowed period of scientific study, say two years, before the remains are returned to present-day tribes for reburial or various rites. After all, it’s not as if these bones belong to a present family of Native Americans, like the remains of someone’s son recovered and returned after a battle.

But I don’t think that claims based only on “oral tradition” or “creation myths,” should be honored at all. In such a case, the remains should then be available to scientists. After all, if we honor such superstitious claims, we are also tacitly honoring the creation myths of anybody, including Christians, Scientologists, and Muslims, each of which has its own creation story. That is government entanglement with religion.

And it’s a double entanglement: one with the myths of Native American groups, and the other with the religion of Wokeism, which makes the SAA into an organization that renders decisions based not on empirical considerations, but on ideology and identity politics.

Here’s the skeleton and skull of Kennewick Man:


World’s oldest representational art: an Indonesian warty pig from 45,000 years ago

January 23, 2021 • 1:45 pm

Here from Science Advances via National Geographic, is the painting of a wild pig from the Indonesian island of Sulawesi. AT 45,000 years old, it’s world’s oldest cave art, and in fact the oldest known representational art of any sort.


Here’s the paper reporting it (click on screenshot), and a free pdf is here:

The very oldest art comes not from Europe or Africa, but from Indonesia; but surely there was much earlier representational art. The subject is presumably a Celebes warty pig (Sus celebensis), a species still with us, and the artist presumably an anatomically modern human (H. sapiens sapiens).

Here’s the subject. Not a bad representation, eh?

From Wild Pig, Peccary & Hippo Specialist Groups.

And a few words from the authors (“AMH” means “anatomically modern humans”)

On the basis of the presently available evidence, we are unable to definitively conclude that the dated figurative rock art depiction from Leang Tedongnge is the handiwork of cognitively “modern” members of our species. However, this seems to be the most likely explanation given the sophistication of this early representational artwork and the fact that figurative depiction has so far only been attributed to AMH everywhere else in the world.

If so, the dated pig image from Leang Tedongnge would appear to provide some of the earliest evidence, if not the earliest, for the presence of our species in Wallacea. The minimum age of this artwork is compatible with the earliest established indications of AMH from excavated deposits in the Lesser Sunda islands, which formerly provided the oldest archaeological evidence for H. sapiens in Wallacea (~44.6 ka cal BP). Hence, dating results for the Leang Tedongnge painting underline the view that representational art, including figurative animal art and depictions of narrative scenes, was a key part of the cultural repertoire of the first AMH populations to cross from Sunda into Wallacea—the gateway to the continent of Australia.

Are human facial expressions universal in which emotions they express?

August 24, 2020 • 1:00 pm

The latest issue of Science Advances has a provocative and clever piece of research aimed at answering a long-standing question—one considered by Charles Darwin himself: are the facial expressions associated with human emotions universal across all cultures? And, if so, is that the result of evolution? The paper suggests that, at least for a limited set of emotions, the answer is yes to both questions. You can read the paper by clicking the screenshot below, or reading the pdf here. The full reference is at the bottom.

Cowen and Keltner note that there have been a fair number of attempts to answer this question, all involving going to remote areas where there is little contact with Westerners, and seeing if people in those areas match photos of Western expressive signals (joy, anger, sympathy) with similar words in their native language. The results have been mixed. That, one would think, already suggests that perhaps facial expressions aren’t universal. (Cultural similarities could be due to either cross-cultural transmission of expressivity, or to a common evolutionary heritage, but dissimilarities among different populations already suggest that culture can’t cause similarities.)

However, the authors suggest these tests are not dispositive, and suggest a better way to see if expressions are universal. What they did was to look at ancient Mesoamerican artworks that depict facial expressions associated with different situations, isolated the facial expressions, got modern observers to guess the emotions depicted, and then asked whether Westerners would judge those expressions to be ones appropriate to the situation depicted by the artwork.  If there was a correlation between the judgements of which emotions were shown on faces, and those that other people guessed would appear in the situations depicted in the sculptures, this would suggest (but not prove) that expressions are not only universal, but perhaps universal because evolution made them universal.

The authors examined tens of thousands of Mesoamerican artifacts (going back to 1500 B.C.) archived by museums, and found 63 pieces of art that met their three criteria for this study:

  1. subjects were portrayed “within one of eight identifiable contexts” (torture, being held captive, carrying a heavy object, embracing another person, holding a baby, in fighting position, playing a ball sport, and playing music).  Examples of each of these are given in the figure below.
  2. The facial expressions could be clearly visible.
  3. The artworks (sculptures and vessels) were deemed authentic by authorities.

Here are examples of the eight contexts for emotion; see the caption for details:

(From paper): Fig. 1 Ancient American sculptures with discernible faces and contexts. (A) Captive from Tonina archeological site (Mexico, 690–700 CE). Photo credit: Mauricio Marat, Instituto Nacional de Antropología e Historia. (1 July 2019). (B) Tortured, scalped prisoner from Campeche (Mexico, 700–900 CE). Baltimore Museum of Art, Kerr Portfolio 2868, photo by J. Kerr. (C) Maya man carrying large stone (Mexico, 600–1200 CE). Kerr Portfolio 8237, photo by J. Kerr. (D) Joined couple (Mexico, 200–500 CE). Los Angeles County Museum of Art (LACMA) AC1996.146.21, gift of C. M. Fearing. (E) Maya woman holding child (600–800 CE). Princeton University Art Museum 2003-26, gift of G. G. Griffin. (F) Kneeling Maya warrior with facial tattoos and shield (Mexico, 600–800 CE), detail. Earthenware and pigment, 15.9 cm by 10.8 cm. Fine Arts Museums of San Francisco 2009.38.2, gift of G. Merriam and J. A. Merriam. (G) Maya ballplayer (Mexico, 700–900 CE). University of Maine HM646, William P. Palmer Collection. (H) Colima drummer (Mexico, 200 BCE–500 CE). LACMA, Proctor Stafford Collection, purchased with funds provided by Mr. and Mrs. Allan C. Balch.

They then isolated the faces from the contexts so that the modern subjects could just look at the faces but not see what the subject was experiencing in the artwork. The 325 subjects were asked them to describe the facial expressions using 30 categories of emotion (e.g., “awe”, “anger”, “shame”, “fear”, and so on and 13 “affective features” like “arousal” and “dominance” (see categories in figure below).

Independently, they asked 114 different subjects, also modern Westerners, to judge what emotions they would expect someone to show in each of the eight situations above. These people were not shown the artworks but simply given the eight situations verbally and asked what emotions you’d expect people to evince.  They then correlated the first subjects’ judgments on what emotions were portrayed by the faces with the expectation of what emotions should be shown from the eight situations, described in words, chosen for analysis.

Here are the correlations between the “read” of subjects from looking just at the faces with the emotions expected judged from subjects looking at the context described in words.

(from paper): Fig. 2 Accordance between emotions perceived in sculptures’ isolated face depictions and Western expectations for the emotions that unfold in eight portrayed contexts. To calculate the accordance between sculptures’ expressions and Westerners’ expectations, we correlated the participants’ average judgments of the emotions and affective features associated with each isolated face and each context across the eight contexts and divided by the maximum attainable correlation given sampling error (see Materials and Methods). Correlations are generally positive, indicating that facial muscle configurations portrayed in ancient American sculptures align, in terms of the emotions they communicate to Westerners, with Western participants’ expectations for the emotions that unfold in different contexts. Error bars represent SEs. Here, we excluded 10 emotions and 1 affective feature used seldom enough that <1/3 of the covariance in judgments was explainable, as a result of which SEs were very large.

Correlations above zero are positive; that is, the expectations of what you’d feel aligned with the subjects’ “read” of the artworks’ faces. As you see, of the 32 emotion categories assessed, 27 had correlations above zero, which alone says something (if there were no correlation, roughly half of the values would be above zero and half below). More important, only six of the 27 positive correlations had standard errors that overlapped zero, or “no correlation”; the rest were statistically significant.

This shows that, in general, the emotions expected by people hearing about the eight contexts for the artwork were those actually discerned by people who looked at the faces of the artwork. And that means that the emotions we expect to see in a modern situation were those that people read from artwork of ancient civilizations. This is turn suggests that at least some facial expressions are “universal”, and people can read them fairly accurately, even in sculptures, as reflecting what people are feeling in a situation. Because these cultures were far removed from ours, this also suggests that the facial expressions weren’t culturally inherited across the ages—that is, we don’t learn the expressions to show determination or distress or the other emotions from others, but express them innately.

One could, I suppose, argue that the Incas and Mayans simply passed on their facial expressions culturally to us as their descendants, but that’s a big stretch since the route for that kind of cultural transmission is dubious: we’re not the descendants of these Mesoamericans. Alternatively, the expressions could have been culturally inherited from our mutual ancestor who lived at least 60,000 years ago when H. sapiens left Africa to populate the world.  If you’re a blank-slater, that’s the argument you’d make.

But it seems more plausible to me that smiling and scowling and showing distress and pain are innate features of our behavior, though I can’t adduce hard evidence for it except that a). babies who haven’t been socialized to show facial expressions of joy or distress still show easily interpretable expressions, presumably before they’re socialized; b). other primates have readable facial expressions without our kind of culture; and c.) one can make a plausible evolutionary hypothesis that humans might have evolved to show expressions that other humans could read: “honest signals.” None of this adds up to a strong evolutionary-psychology argument, but one can agree, from the results above, that there is some universality across millennia in how humans show emotions on their faces.

Finally, the authors used a method called “principal preserved components analysis” to gather in one basket the main “dimensions” (combinations of emotions) that best explain the correlations shown above. From this they determined that three combinations of factors combine to explain at least five types of facial expressions on sculptures. Those expressions, the ones most easily seen as “universal, are these:

  1. “pain”, often in the context of torture
  2. “determination”/”strain”, in sculptures showing heavy lifting
  3. “anger”, usually in sculptures depicting combat
  4. “elation”, seen in “contexts of familial or social touch”, and
  5. “sadness”, as in being held captive after defeat.

The paper has other analyses, but these are the main conclusion. The authors also give several caveats, and you can have a look at those.

The tentative takeaway lesson is that, even after millennia, we can pretty accurately read the facial expressions of people from different cultures.  That is, there are some universals, at least between ourselves and Mesoamericans, in the expression of emotions. Whether that be the result of cultural inheritance or a universal code for expression that resides in our DNA (or a combination of these factors) can’t yet be discerned, but I’m betting on a largely biological-determinism explanation. And so are the authors, at least judging from their final paragraph:

The present results thus provide support for the universality of at least five kinds of facial expression: those associated with pain, anger, determination/strain, elation, and sadness. These findings support the notion that we are biologically prepared to express certain emotional states with particular behaviors, shedding light on the nature of our responses to experiences thought to bring meaning to our lives.

Here are a few more faces and the contexts in which they appear (see paper for explanation), but I think you can guess pretty well.

h/t: cesar

Cowen, A. S. and D. Keltner. 2020. Universal facial expressions uncovered in art of the ancient Americas: A computational approach. Science Advances 6:eabb1005.

A very old tool

October 16, 2018 • 2:00 pm

Here’s my hand holding a 130,000 year old flint spearhead created by a Neanderthal living near what is now Krapina, Croatia. It’s a beautiful point, and amazing to think that this was chipped by a hominin so long ago.

I learned a ton today at the Croatia Natural History Museum, as we had a special visit to the Neanderthal collection and got a close-up view of the stunning bones and artifacts. This required special permission, and I am most grateful to the curator, Dr. Davorka Radovčić, for taking the time to show us the specimens and give us detailed explanations.

I will do a whole post on our visit, with lots of cool photos, but here’s a teaser:

Okay, one more. This is a very special skull (all bone, no reconstruction), but I’ll tell you about it later:


Did modern Homo sapiens evolve in different parts of Africa?

July 15, 2018 • 9:30 am

The general view of human evolution among both scientists and laypeople is that “modern” Homo sapiens emerged from one single area in East Africa: perhaps from just a single population. That population supposedly evolved from an earlier ancestor of unknown identity—perhaps Homo erectus—underwent the transformation into the group of characters that identify our species, and then spread throughout the world. (This is independent of the evolution of what I consider other extinct subspecies of H. sapiens, like Neanderthals and Denisovans, which may have originated from single populations.)

A new paper by Eleanor Scerri and many colleagues, however, questions this conventional wisdom. The paper, an opinion piece rather than a scientific paper, appears in Trends in Ecology and Evolution (click on screenshot to see it, free with UnPaywall; the reference is at bottom, and a free pdf is here), limns what is known as the “multiregional hypothesis” for modern H. sapiens. This is the view that there were many semi-isolated populations of our ancestor scattered throughout Africa, and that each evolved quasi-independently because there were geographic and climatic barriers that reduced gene flow between the groups.

Each population then evolved different traits—of behavior, morphology, and mentation—that eventually combined through more extensive migration into one species that then spread throughout Africa and then the world. It is as if a group of tailors were to craft a garment, each responding to local tastes and materials, and then those garments were combined into one garment that became the “standard and universal” one.

“Anatomically modern humans” date from about 315,000 years ago, with the first finds being in Moroccan caves at Jebel Irhoud. These finds contravened the idea that the earliest humans evolved in East Africa, and suggest that already at that time modern H. sapiens was widely distributed throughout Africa. However, the Jebel Irhoud skulls, while having most of the features of modern human skulls, were relatively elongated. Here’s the earliest find (left) compared with a more recent (95,000 years old) modern H. sapiens skull. The elongation of the earlier one is evident.

Multiregional evolution is supported by the authors’ contention that human populations were structured morphologically as late as 15,000 years ago, with some retaining more ancestral skeletons and others being more advanced—but all considered by anthropologists to be part of the single species H. sapiens sapiens (“modern” Homo sapiens).

Likewise, different populations of H. sapiens sapiens had different stone tools at about the same time, with some being more advanced than others, and this regional differentiation also held for other cultural artifacts like bone tools and shell beads. This too suggests a subdivided species, perhaps with different populations having different degrees of mental/neurological evolution.

What caused this differentiation? The authors aren’t sure, but say a likely cause was different environments that not only isolated populations from each other, but imposed different selection pressures on them. Climate is an obvious difference, with the figure below showing big differences in precipitation among parts of Africa that housed different populations of H. sapiens sapiens (areas within colored squares). Note the variation among localities even at the same time. These would cause obvious barriers as dry places would impede migration between wet places (the Sahara region, with less precipitation, is an obvious barrier).

(from paper): Middle and Late Pleistocene African Environmental Variability in Space and Time. (Left) Map of Africa with key archaeological and fossil sites discussed in the text. Colored boxes indicate averaged regions for simulated precipitation changes from the transient glacial/interglacial LOVECLIM climate model experiment [81]. (Right) Precipitation changes (%) relative to the long-term 784 thousand year mean in the key regions highlighted in left panel, as simulated by transient 784 thousand year-long LOVECLIM climate model simulation [81]. From top to bottom the regions are eastern equatorial Africa, southern Africa, northwestern Africa, and the central Sahara region.
Precipitation would affect the vegetable and animal food available, and hence the means of foraging and food preparation, and that would affect selection for tool usage and for forming different kinds of tools. Those pressures, in turn, could affect social evolution and the structure of our brains. Further, random differences in the frequencies of genes arising by genetic drift could act as different beginning substrates for natural selection, as the course of natural selection depends on its genetic and morphological starting points.

So there is some evidence for the authors’ multiregional hypothesis, which, as Ed Yong characterizes in an article in The Atlantic like this:

The best metaphor for this [the authors’ “multiregionalism” hypothesis] isn’t a tree. It’s a braided river—a group of streams that are all part of the same system, but that weave into and out of each other.

These streams eventually merge into the same big channel, but it takes time—hundreds of thousands of years. For most of our history, any one group of Homo sapiens had just some of the full constellation of features that we use to define ourselves. “People back then looked more different to each other than any populations do today,” says Scerri, “and it’s very hard to answer what an early Homo sapiens looked like. But there was then a continent-wide trend to the modern human form.” Indeed, the first people who had the complete set probably appeared between 40,000 and 100,000 years ago.

But there’s evidence against the hypothesis as well, the most telling being genetic analyses suggesting that different populations of humans in Africa didn’t diverge from each other 300,000 years or so ago, but between 100,000 and 150,000 years ago, suggesting a genetic and populational uniformity before that.

So we have a conflict between what the genetic data tell us and what morphology and tool use tell us.  This may not be a problem since the genetic data is not yet rock-solid. Nevertheless, we should take the paper as tentative but suggestive, which is why it’s an “opinion” piece rather than a regular scientific article.

The implications aren’t that important for non-paleobiologists. Although the multiregional theory suggests that our species emerged in a patchwork fashion, like Yong’s braided rivers, we know that as that species spread throughout the world in perhaps several egresses from Africa, those spreads did not emanate from many different places in Africa. And they don’t overturn the indubitable fact that humans are, in essence, complex African apes.


Scerri, E. M. L. et al. 2018. Did Our Species Evolve in Subdivided Populations across Africa, and Why Does It Matter? Trends Ecol Evol., online publication,  DOI:

Finally: a sensible discussion of “race”

March 23, 2018 • 11:15 am

And by “sensible,” of course, I mean a discussion that aligns with my own views. I’ve often written that while there are no finite and strongly genetically demarcated human “races”, there are meaningful and statistically diagnostic differences between populations, ethnic groups, or whatever you want to call them. This is in opposition to the common Left-wing view that races are purely “social constructs” having no biological reality.

Well, there aren’t a finite number of groups whose members are 100% genetically differentiated from other groups. But when you take all genes together, there are sufficient average frequency differences that one can discern statistical clusters that, in turn, allow you to use lots of genes to pretty much diagnose where somebody’s from and who their ancestors were. These “statistical clusters” are real, not social constructs, for they fall out regardless of the politics or biases of the investigator.

Recognizing their existence by no means justifies bigotry or stereotyping, but we shouldn’t dismiss the existence of those clusters simply because, in the past, people with an incorrect idea of “race” have used differences to justify segregation and prejudice. Yet all too often, as with genetic differences among ethnic groups, behavioral differences between the sexes, and evolutionary psychology, those on the Left simply dismiss entire fields because of a fear that scientific research will justify discrimination. And in theory it could, as it did in the past, but it’s better to know the facts and at the same time absorb the idea that the moral and legal equality of all humans, and the equality of opportunity they deserve, does not depend on evolutionary or genetic details. For if it did, then scientific findings could be used to justify prejudice—something that all humanists reject. Asserting that entire fields, like genetic analysis of human ethnic groups, are simply parsing “social constructs” is a form of anti-intellectualism that will stifle scientific progress. If some Leftists had their way, for instance, there would be no evolutionary psychology, no attempt to understand the evolutionary roots of modern human behavior. Do we really want to impose a moratorium on such work?

The recognition of genetic clusters as meaningful entities is the point that David Reich makes in the article given below. Reich, as you may know, is an accomplished professor of genetics at Harvard who’s done a lot of work on DNA-based human and primate phylogenies, human disease genes, interbreeding among ancient lineages of hominins (e.g., Denisovans, Neanderthals, etc.), and mapping human ancestry by looking at statistical grouping. (There’s a big NYT article about his work here.)

I highly recommend you read his essay in the New York Times‘s Sunday Review (click on screenshot):

I’ll give just two quotes from Reich: one about the scientific data and the other about its moral implications—or lack thereof. But read the article!

The data:

[After the 1972 paper of my advisor Dick Lewontin], a consensus was established that among human populations there are no differences large enough to support the concept of “biological race.” Instead, it was argued, race is a “social construct,” a way of categorizing people that changes over time and across countries.

It is true that race is a social construct. It is also true, as Dr. Lewontin wrote, that human populations “are remarkably similar to each other” from a genetic point of view.

But over the years this consensus has morphed, seemingly without questioning, into an orthodoxy. The orthodoxy maintains that the average genetic differences among people grouped according to today’s racial terms are so trivial when it comes to any meaningful biological traits that those differences can be ignored.

The orthodoxy goes further, holding that we should be anxious about any research into genetic differences among populations. The concern is that such research, no matter how well-intentioned, is located on a slippery slope that leads to the kinds of pseudoscientific arguments about biological difference that were used in the past to try to justify the slave trade, the eugenics movement and the Nazis’ murder of six million Jews.

I have deep sympathy for the concern that genetic discoveries could be misused to justify racism. But as a geneticist I also know that it is simply no longer possible to ignore average genetic differences among “races.”

Groundbreaking advances in DNA sequencing technology have been made over the last two decades. These advances enable us to measure with exquisite accuracy what fraction of an individual’s genetic ancestry traces back to, say, West Africa 500 years ago — before the mixing in the Americas of the West African and European gene pools that were almost completely isolated for the last 70,000 years. With the help of these tools, we are learning that while race may be a social construct, differences in genetic ancestry that happen to correlate to many of today’s racial constructs are real.

Recent genetic studies have demonstrated differences across populations not just in the genetic determinants of simple traits such as skin color, but also in more complex traits like bodily dimensions and susceptibility to diseases. For example, we now know that genetic factors help explain why northern Europeans are taller on average than southern Europeans, why multiple sclerosis is more common in European-Americans than in African-Americans, and why the reverse is true for end-stage kidney disease.

I am worried that well-meaning people who deny the possibility of substantial biological differences among human populations are digging themselves into an indefensible position, one that will not survive the onslaught of science. I am also worried that whatever discoveries are made — and we truly have no idea yet what they will be — will be cited as “scientific proof” that racist prejudices and agendas have been correct all along, and that those well-meaning people will not understand the science well enough to push back against these claims.

And how we should handle the future discoveries of genetics:

For me, a natural response to the challenge is to learn from the example of the biological differences that exist between males and females. The differences between the sexes are far more profound than those that exist among human populations, reflecting more than 100 million years of evolution and adaptation. Males and females differ by huge tracts of genetic material — a Y chromosome that males have and that females don’t, and a second X chromosome that females have and males don’t. [JAC: I find this statement somewhat misleading, because he’s talking about “biological” differences, not differences in genetic content, and the Y chromosome doesn’t have many genes.]

Most everyone accepts that the biological differences between males and females are profound [JAC: Again, it’s not clear what he means by “profound,” but I’d agree that they are there and that they do explain differences between the sexes in both morphology and behavior.] In addition to anatomical differences, men and women exhibit average differences in size and physical strength. (There are also average differences in temperament and behavior, though there are important unresolved questions about the extent to which these differences are influenced by social expectations and upbringing.)

How do we accommodate the biological differences between men and women? I think the answer is obvious: We should both recognize that genetic differences between males and females exist and we should accord each sex the same freedoms and opportunities regardless of those differences.

It is clear from the inequities that persist between women and men in our society that fulfilling these aspirations in practice is a challenge. Yet conceptually it is straightforward. And if this is the case with men and women, then it is surely the case with whatever differences we may find among human populations, the great majority of which will be far less profound.

An abiding challenge for our civilization is to treat each human being as an individual and to empower all people, regardless of what hand they are dealt from the deck of life. Compared with the enormous differences that exist among individuals, differences among populations are on average many times smaller, so it should be only a modest challenge to accommodate a reality in which the average genetic contributions to human traits differ.

It is important to face whatever science will reveal without prejudging the outcome and with the confidence that we can be mature enough to handle any findings. Arguing that no substantial differences among human populations are possible will only invite the racist misuse of genetics that we wish to avoid.

Between the unwarranted pseudoscientific statements of Nicholas Wade and James Watson on one hand (both criticized in Reich’s article) and the genetic blank-slateism of various ideologically-biased scientists and cultural anthropologists (who don’t act like scientists) on the other, lies the reasonable position—the one limned by Reich.

Greg’s Take on Reich’s Article

by Greg Mayer

I also like Reich’s article, but if he hopes to be able to talk about genetic differentiation, he’s going to have to stop accepting the “race is a social construction” fallacy, because that means everyone who thinks race is a social construction, or been convinced it is because they keep getting told it is, will ignore everything else he says. As he points out, there is measurable genetic variation; that that variation can be important (clinically, cognitively, etc.); and that that variation allows the identification of the geographic origin of individuals– and the latter is what race means. (As always, I use the zoological definition of a geographic race or subspecies. Subspecies may be described when it is the case that if you show me a specimen I can tell you where it is from, and, conversely, if you tell me where it is from I can tell you what it looks like.) The mass of genetic data on humans now allows us to divide indigenous populations  (i.e. pre-Columbian) into so many races that fit the zoological definition of a race that one of the chief arguments against recognizing races is that there are too many recognizable races– 23 and Me is selling microracial identification on television! Very fine scale genetic data make recognition of geographic groupings so easy that the problem with subspecies isn’t that you can’t tell them apart, but rather you can tell everything apart, even local populations.  Nomenclaturally, subspecies are optional, and there could be reasons, both practical and social, not to name them.

Reich cites Dick Lewontin‘s 1972 apportionment of diversity finding (which, of course, is true), but then doesn’t mention (or perhaps even realize) that that finding  says nothing about whether there are recognizable races. What Reich does do, although more indirectly than I would, is to argue that human moral equality must not rest upon an empirical finding of no genetic differences, because then the finding of genetic differences will undermine the argument for moral equality. I 100% endorse him on the principle that human moral equality should NOT depend on an empirical argument about genetic differentiation. The problem with basing human moral and civil equality on empirical claims about human biological similarity is that such claims may prove to be mistaken. Tony Edwards, in his commentary on Dick’s 1972 paper, says it quite nicely:

“But it is a dangerous mistake to premise the moral equality of human beings on biological similarity because dissimilarity, once revealed, then becomes an argument for moral inequality.”

[Also, Reich seems terribly naive if he thinks “Most everyone accepts that the biological differences between males and females are profound.” I predict he will be assailed from the left on this point. And, Jerry and I wrote our commentaries independently of one another.]

h/t: Rodney, Greg

Readers’ fieldwork pictures

January 15, 2018 • 8:45 am

I’ve put up posts before from Dorsa Amir, a graduate student in biological anthropology at Yale. Here’s her latest contribution: a set of photos from her fieldwork (more photos here). Dorsa’s notes are indented:

As an anthropologist, one of my goals is to explore human behavioral variation across diverse contexts. In conjunction with the larger Shuar Health & Life History project, I have had the amazing opportunity to work with the Shuar, a population indigenous to the Ecuadorian Amazon. The Shuar are forager-horticulturalists who still hunt, fish, and cultivate crops for most of their subsistence, and largely function as small-scale societies. Working with communities of people still living in many ways like their ancestors has been an eye-opening experience when pondering human evolution and culture change. One of the most salient differences between their way of life and ours, in my experience, has been the resilience and independence of Shuar children, who furnish many of their own calories, care for their siblings, and live a much more independent life than their Western counterparts. (I’ve written a bit more about this in a piece for Nautilus). Below are some photos from several summer fieldwork trips.

Note the tamarin:

In the spirit of wildlife photos, here’s Shuar woman with her pet kinkajou [Potos flavus]:

Dorsa had an orange and white cat named Emerson, but wants us to know she’s expanded the felid family to include Hamilton (“Hammy”), named after the late evolutionary biologist W. D. Hamilton. Here’s the happy couple: