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A fascinating paper in Science Advances today looks at the way that a small platyrrhine monkey species conveys information about predators in its vocal communication system: “Titi monkeys combine alarm calls to create probabilistic meaning”.

The titi monkeys have two kinds of alarm calls, which they can combine together in complex sequences. The research by Mélissa Berthet and coworkers shows that the sequences carry information about not only the type of predator but also the location of the predator. Unlike human sentences, which are comprised of words that have distinct meanings, these titi monkey call sequences are probabilistic, that is, it is not the precise order or number of calls, but their quantity in combination that predict to a feature of the environment.

A couple of paragraphs from the discussion of the paper are enlightening:

Human and nonhuman animals (hereafter referred to as animals) live in environments where most stimuli appear in a continuous form, but perception is often categorical (9). For example, although rainbows consist of continuously changing wavelengths, they are perceived by humans as color bands. Similar effects are found in communication systems, including human speech. Acoustically, the human vocal tract can gradually alter the second formant of the syllable from the sound “b” (as in “beer”) to “d” (as in “deer”) and then to “g” (as in “gear”), although they are perceived in sharply categorical ways by listeners (10). Another example comes from the American Sign Language, where the hand configuration gradually differs between the words “please” (the thumb and all the fingers are selected) and “sorry” (only the thumb is selected) but is perceived categorically by deaf signers (11).

Linguists have focused quite extensively on the categorical encoding of human language. In looking for precursors or analogues of human communication in other animal communication systems, linguists and animal behaviorists have often paid attention to such categorical systems – for example, the alarm calls of vervet monkeys, which seem to form clear categories relating to predator types.

Yet maybe there is more to be seen in the simple call systems of non-human primates than correspondences between calls and features of the environment:

Although the notion of categorical meaning is intuitively compelling, it is not necessarily the default mode of animal perception. Categorical perception has been a major theoretical pillar in animal communication research, particularly because of its intuitive link to linguistic theory. For example, Macedonia and Evans [(16), p. 179] presupposed that external events are processed in categorical terms (“…all eliciting stimuli must belong to a common category”). Although this approach has been fruitful and productive, it has also generated enigmas suggesting that the underlying theory may have to be revised. For example, in a seminal paper, Cheney and Seyfarth (17) were puzzled by the fact that animals appeared to have very few categorical semantic labels, mostly limited to predator classes and a few social events. One possibility is that graded meanings are the default way of animal communication [e.g., (18)], although this hypothesis has been much ignored and considered as less interesting than categorical perception (16). Our study suggests that explaining animal communication on categorical terms alone may be too restrictive and anthropocentric and may explain the struggle to extract meaning from some animal communication systems.

I think this is cool. It suggests that natural language learning systems, which include strongly probabilistic features, might make some headway with animal communication systems.

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There is much that could be said about Charles Darwin’s discussion of human races in Descent of Man. In Chapter 7 he embarked on a long discussion of whether races of humans should be considered as different species. Throughout, he argues that they should not, but Darwin presented and weighed the best arguments he can find on either score.

As I read the following quote, I wanted to tweet it, but it’s too long:

Every naturalist who has had the misfortune to undertake the description of a group of highly varying organisms, has encountered cases (I speak after experience) precisely like that of man; and if of a cautious disposition, he will end by uniting all the forms which graduate into each other, under a single species; for he will say to himself that he has no right to give names to objects which he cannot define.

I think that’s a wonderful precept. If every scientist refrained from “giving names to objects” without a clear definition, it would save marvelous confusion.

The immediate context of this sentence is Darwin’s discussion of what he describes as “the most weighty of all the arguments against treating the races of man as distinct species”, namely, that human races grade continuously into each other. As a consequence, he notes:

Man has been studied more carefully than any other animal, and yet there is the greatest possible diversity amongst capable judges whether he should be classed as a single species or race, or as two (Virey), as three (Jacquinot), as four (Kant), five (Blumenbach), six (Buffon), seven (Hunter), eight (Agassiz), eleven (Pickering), fifteen (Bory St. Vincent), sixteen (Desmoulins), twenty-two (Morton), sixty (Crawfurd), or as sixty- three, according to Burke. (18. See a good discussion on this subject in Waitz, 'Introduction to Anthropology,' Eng. translat., 1863, pp. 198-208, 227. I have taken some of the above statements from H. Tuttle's 'Origin and Antiquity of Physical Man,' Boston, 1866, p. 35.) This diversity of judgment does not prove that the races ought not to be ranked as species, but it shews that they graduate into each other, and that it is hardly possible to discover clear distinctive characters between them.

Many of today’s issues in biology were already known to Darwin. It is easy to forget how much his presentation of such issues shaped the way later authors would present them. He sometimes packaged the ideas of others, but the fact that Darwin promoted and gathered such ideas together tended to place them into the biological canon.

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The New York Times Magazine today has a long-read article about Cayo Santiago, the island just off Puerto Rico where a large colony of rhesus macaques was introduced back in the 1930s to supply the medical research trade. The island became a laboratory where researchers could study every aspect of the free-ranging macaques’ lives.

In 2017, Puerto Rico was hit hard by Hurricane Maria, with enormous effects on the people of the island. Cayo Santiago was also hit, stripping much of its forest. The macaques weathered the storm relatively well, but researchers have found longer-term effects. The article explores these effects on the macaques, explains the research and its history, and highlights the struggles of the people of Puerto Rico: “Primal Fear: Can Monkeys Help Unlock the Secrets of Trauma?”

In October 2018, Lauren Brent began analyzing some of the preliminary poststorm observational data and began to notice unexpected patterns. There seemed to be two things going on. One, the monkeys seemed to be expanding their social networks, increasing the number of individuals that they had meaningful relationships with. Two, the monkeys appeared to become more tolerant of one another. They were living under radically diminished circumstances, competing for resources that had never been in such short supply, like edible leaves and the temperature-reducing shade that those leaves produced, but the amount of inter- and intratroop violence had seemed to taper off significantly. It was as if the hurricane had bonded even former foes against a common enemy and made the monkeys much more tolerant of life’s everyday frustrations, at least in the early days.

I’ve chosen to quote a passage that is monkey-centric, but the article really is about the human stories – researchers, local research assistants, and other people caught in an extraordinary and often tragic set of circumstances.

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In The Conversation this week, archaeologist Amanuel Beyin and his colleagues Ahmed Hamid Nassr and Parth Chauhan describe their work surveying the Red Sea coast of Sudan for early archaeological sites: “Red Sea stone tool find hints at hominins’ possible route out of Africa”.

This is valuable work and I’m happy to see the authors sharing it. They are exploring for evidence of ancient hominin activity in a place where hominins should logically have been abundant in the Pleistocene, and they’re finding sites:

Recently we led a research team to fill the existing evidence gap about our ancestors’ route out of Africa. Our focus was on the western periphery of the Red Sea. This area links the fossil-rich Horn of Africa and the Sinai Peninsula, which is the only land bridge that could have facilitated direct hominin movement between Africa and Eurasia in the past two million years.
We found evidence of hominin settlement in the area in the form of stone artifacts that suggests this region was a key early dispersal corridor – and possibly the first. That evidence includes stone tools, colloquially referred to as handaxes or bifaces. These were associated initially with the first fully bipedal (upright walker) hominin species, Homo erectus, and subsequently with other species.

Handaxes are highly recognizable evidence because they were not commonly produced in Africa after 150,000 years ago. For the archaeologist, they give a rapid indicator that sites of Early or Middle Pleistocene antiquity are present—although handaxes can erode out of older sites and lie on the surface for a very long time. In any event, the presence of a network of ancient populations on the Red Sea coast is a logical prediction and great to find. This may be a region that was important to the repeated connections between African and Eurasian populations during the Middle Pleistocene.

I’m skeptical about the concept of “dispersal corridors” for hominins. I’ll reflect on that idea at greater length some other time, I don’t want to detract from the value of these authors sharing their work. All I’ll say is that I was worried when I saw the headline of this piece pointing to the “possible route out of Africa” that the work would have a lot of the usual nonsense about “southern route” and “northern route” possibilities for modern humans. So I was very pleasantly surprised that the authors were taking a broader view and filling in some important unknowns with respect to much earlier archaeological material.

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I’ve been reading a new open access book by the anthropologist Rob Borofsky: An Anthropology of Anthropology: Time to Shift Paradigms?. The book is available for free download.

Borofsky has become well known as an advocate for “public anthropology”, the idea that anthropology should interact with a broader public, and be of service to the public.

I may point to a number of passages in the book as I read it. There is a great paragraph on page 23 that I want to highlight. Borofsky looked at several journals including the American Anthropologist and others to assess how many articles involve more than a single subfield – that is, when the research question actually requires core concepts and original data from two or more different kinds of anthropology.

The lack of subfield integration in times past is readily apparent when you read through old issues of the American Anthropologist. So why would anthropologists affirm something about the past—that the subfields previously collaborated in significant ways—that is clearly at variance with established fact? The myth of an earlier “golden age” of disciplinary integration constitutes a “social charter” for today’s departmental structure: It holds up an ideal. Disciplinary integration is imposed on the past—an “invention of tradition,” to quote Eric Hobsbawm and Terence Ranger. But it also does more. It implicitly represents a call for more disciplinary integration to resolve the current problem of departmental fragmentation. The myth allows anthropologists to address a problem of social structure—intellectual fragmentation within a department—without the pain of anyone actually having to change. It allows them to pretend that they all once worked together as a team.
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Science magazine has a recent online article by journalist Lizzie Wade looking at the growing influence of ancient aliens and other pseudoarchaeological nonsense in the United States: “Believe in Atlantis? These archaeologists want to win you back to science”.

I’ve selected a passage in the middle of the article to quote:

Adding to archaeologists’ sense of responsibility is that “many of these ideas started within mainstream archaeology,” says Jeb Card, an archaeologist at Miami University in Oxford, Ohio. “We have to own these stories.”
For example, white settlers and early archaeologists in 19th century North America excavated elaborate pre-Columbian burial mounds—but ascribed them to a lost “moundbuilder race” that was killed by the ancestors of Native Americans. Former President Andrew Jackson used those ideas to justify displacing Native Americans from their lands.
Today, white nationalists make similar claims. To argue for Europeans’ deep roots in the Americas, they have latched onto Vinland, a short-lived medieval Viking settlement in eastern Canada, and the “Solutrean hypothesis,” which argues that the Americas were first peopled by arrivals from Western Europe. Neither claim started as pseudoarchaeology—Vinland was real, and the Solutrean hypothesis was proposed by mainstream archaeologists, then tested and ruled out—but they have been twisted for ideological ends. A white supremacist accused of murdering two people on a train in Portland, Oregon, in 2017 included the words “Hail Vinland!!!” in a Facebook post less than a month before the attack.

When it comes to mainstream media figures who are promoting pseudoarchaeology, I think we need to focus on the money. Pseudoarchaeology is a business. The media organizations, actors, and authors who are promoting this nonsense are profiting enormously from it. They’re quacks.

That money is coming, directly and indirectly, from people who often have a genuine and deep interest in knowing about the human past. Pseudoarchaeology is stealing their money and betraying their real quest for knowledge by feeding people nonsense.

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The current issue of American Anthropologist has a series of short essays by biological anthropologists, featured as a “Vital Topics Forum” in the journal. The essays come from anthropologists of a diversity of backgrounds and training, including many groups that have been historically underrepresented in this field of science. According to the journal, these are open access, and I may feature several of these essays over coming weeks.

Today I read the essay by Milena Shattuck, “Research in a Non‐Research Position”. One of the ongoing realities of academic institutions in the U.S. and internationally is a shift toward contingent (adjunct and other non-tenure-track) faculty for many teaching and service roles. As PhD scientists finish their degrees and proceed through their early career, they are increasingly finding that research is not part of the jobs they are getting. That reality has important implications for how we train and mentor PhD students, and also for how we conceive of research.

[G]iven the constraints that most people in our field face, it may be time to rethink our idea of who belongs at the table. For starters, given that teaching responsibilities are increasingly shifted onto NTT faculty, we need to acknowledge their importance in training the next generation of scientists. However, we also need to consider their potential role in research. High‐budget projects that produce large datasets are absolutely necessary to advance our field. But we must not conflate the research with the researcher, and those who manage to produce knowledge despite limited means should be valued too. Rather than be sidelined, NTT faculty should be actively sought out for collaborations. Ignoring 70 percent of academics can only harm science.

I would add, at the same time that universities are creating more non-research positions, they are also expecting more and more undergraduate research experience for students who apply to pursue higher degrees. This is a contradiction. I agree that research experience is valuable for students, and to provide it we must value and provide more support for the research roles of many instructors, even those in primarily teaching positions.

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John Hawks by John Hawks - 1M ago

The Age has an article describing the work of two anatomists who want to bring new high-fidelity plastic models into medical anatomy training: “Buster, the perfect human made of plastic, is the future of anatomy”.

There are VR simulators and screens that can slice a virtual human body in two with the swipe of a finger. But the secret real secret here is a machine, pioneered by Professor McMenamin, that can print out plastic human bodies. No one else in the world can do this.
First, a high-accuracy CT scan of a donor body is obtained. Then, about half-a-million dollars’ worth of cutting-edge 3D printers build a copy out of soft plastic.
They are so accurate, calling them models does not do them justice. Professor McMenamin prefers “replica”.

I know many anatomy professors very well. All of them attest that the experience of learning anatomy with donor cadavers cannot be matched by any artificial model. The gift that donors give when they will their bodies to medical education is precious and irreplaceable. The linked article shares the Australian professors’ view, which is aligned with mine.

But even though there is no replacement for experience with real human cadavers, I see great promise in 3D models to broaden anatomy education. In undergraduate courses, we cannot match the experience of gross anatomy training in the medical school context. Having high-resolution models like these from real individuals would enable us to bring human variation into a much broader sample of courses. That would be helpful for health sciences training by giving pre-med and pre-nursing students more repetitions with better materials. It would also broaden knowledge and training in human anatomy outside of the health professions.

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Forensic genealogy is now mainstream. From Bloomberg Businessweek, a report by Kristen Brown: “A Researcher Needed Three Hours to Identify Me From My DNA”.

It wasn’t hard. I’d previously sent a DNA sample to the genetic testing company 23andMe Inc. and then uploaded my data anonymously to a genealogy website. Researcher Michelle Trostler was able to access my data from that site and spent an afternoon looking for connections that would help her put a name to my data. The task was so easy that in the meantime she rewatched a season of Game of Thrones.

Seems to me that we are only a few steps in synthetic biology away from people being able to conceive “three-parent” children, where some of the DNA is modeled on the publicly available sequence of someone off the internet.

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The online journal Sapiens invited me to write up my thoughts about the announcement of Homo luzonensis yesterday. I do have more to say about this cool discovery, but I wanted to share that article here also, for readers who might not have seen it:

This week, anthropologists working in the Philippines unveil new fossils that they say belong to a previously undiscovered species of human relatives. The fossils come from Callao Cave, on the northern island of Luzon, and are at least 50,000 years old.

The team, led by Florent Détroit of the National Museum of Natural History in Paris, have named the new species Homo luzonensis after the island where it lived.

Teeth from the Callao Cave individual that serves as the holotype for Homo luzonensis, CCH6.

With only seven teeth, three foot bones, two finger bones, and a fragment of thigh, the set of Callao fossils doesn’t give much to go on. Their small size is reminiscent of Homo floresiensis, the tiny-bodied species discovered in 2003 on the island of Flores, Indonesia, that lived around the same time. But there aren’t enough remains here to say just how tall Homo luzonensis was. And, unfortunately, the team was unsuccessful in attempts to find DNA. Many people will wonder, on such slim evidence, if the declaration of a new species is warranted.

I was fortunate to be a part of the team that discovered the new hominin species Homo naledi, which lived in South Africa around 250,000 years ago. That work was published in 2015. Such discoveries seemed almost unimaginable 20 years ago, when I was finishing my Ph.D. At that time, some of the most respected anthropologists actually suggested that the hunt for hominin fossils was almost over. Funding agencies directed their efforts away from exploring for new fossils and toward new technologies to wring more precious data from fossils discovered in the past.

Yet the last 20 years have seen an unprecedented burst of new discoveries. Some, like H. naledi and H. floresiensis, represent branches of the human family tree that separated from the modern human line quite early and yet survived until a surprisingly recent time.

Was H. luzonensis another such population? To establish that these fragmentary fossils justify recognition as a new species, a key first step is to exclude their membership to modern humans. Living people of the Philippines include some very small-bodied groups. Small size alone is not enough to place the Callao fossil teeth outside the range of modern people.

To go further, Détroit and colleagues studied the details of the bones and teeth. Together, they represent a mash of features that are confusingly reminiscent of a huge range of other hominins, and together make for something new and hard to classify. The molars, for example, are small compared to every other known species, while the adjacent premolars, bizarrely, are not so small. The molar crowns have a simple, humanlike pattern, but the premolars bear resemblance to the larger teeth more typical in older species, including H. floresiensis and some early specimens of Homo erectus. Some premolars have three roots, as sometimes found in H. erectus and more distant human relatives. The toe and finger bones also seem different from modern humans: One finger bone is curved, and the toe doesn’t seem to have been able to bend upward at the ball of the foot as much as ours. In some ways, these bones resemble hominins that lived more than 2 million years ago, such as Lucy’s species, Australopithecus afarensis. No other known species shares the whole set of features found at Callao.

So, what does this discovery mean? To me, it solidifies the case that ancient human relatives were a lot smarter and more adaptable than we used to give them credit for.

The low sea level stand of the last glaciation is just below 120 m, indicated here on the map. Flores, Sulawesi, and Luzon all have archaeological remains that predate any evidence of modern human presence in the region.

Flores lies about 2,000 miles to the south of Luzon, but both islands share a peculiar geography: Land bridges never connected these islands to the Asian continent. Another large, disconnected island in the region is Sulawesi. There, stone tools from a site called Talepu were made by hominins more than 118,000 years ago, though no fossils have been found yet to indicate who was making them. Some anthropologists have thought that the colonization of such islands over water was due to luck. Maybe ancient storms or tsunamis washed a few unsuspecting survivors onto ancient beaches. But where one strange event might be attributed to luck, three are much more interesting.

The evidence for life on these islands goes back a long way. Some hominins were making stone tools on Flores more than a million years ago, and the oldest hominin fossil on that island is around 700,000 years old. Last year, paleoarchaeologist Thomas Ingicco, from the National Museum of Natural History in Paris, and colleagues reported on work at the site of Kalinga, Luzon. There, they found stone tools and butchered rhinoceros bones, also around 700,000 years old. Very early forms of Homo must have surpassed barriers and found new ways of life in places with very different climates and plant and animal communities than their African ancestors. Meanwhile, within Africa, a diversity of hominin species continued to exist throughout most of the last million years.

It’s too early for us to say whether the earliest inhabitants of Flores and Luzon gave rise to H. floresiensis and H. luzonensis. I wouldn’t bet on it. Many new arrivals may have come between the first occupations and the later appearance of modern people in the region. One such arrival may have been the Denisovans, a mysterious group known from DNA evidence. Today’s people of the Philippines bear genetic traces of Denisovan ancestry, and new analyses of Denisovan genetic contribution in New Guinea suggest deep roots for this ancient group. Could the Denisovans have existed on Flores, Sulawesi, or the Philippines?

To answer such questions, we must reinvest in exploration. The new discoveries of the past decade or so have transformed the field of human origins. New methods of exploration, and more intensive exploration of underrepresented regions, have introduced a new paradigm. Ancient groups of human relatives were varied and adaptable. They sometimes mixed with one another, and that mixing gave rise to new evolutionary solutions. Our species today is the lone survivor of this complicated history. We have replaced or absorbed every other branch of our family tree.

Many more of these branches are surely waiting for us to find them.

This work first appeared on SAPIENS under a CC BY-ND 4.0 license. Read the original here.

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