Some links relevant to the role of the humanities.
Ben Lillie, director of The Story Collider, writes about how the gurus of science communication advice have ignored knowledge in the humanities: "The humanities of science communication".
This is shocking. Not the conclusion, which is clearly correct. The problem is that the conclusion has been known to comedians for at least the last several thousand years. When I trained in improv comedy the third class was on callbacks, the jargon term for that technique. The entire structure of an improv comedy set is based around variations on the idea that things are funnier if they’re repeated. And yet to the authors it was “common knowledge” that this will spoil a joke. There is a long tradition of people who know, from experience, how this works, and yet the idea of asking them is not evident anywhere in the paper. This is the problem — the sense that the only valid answers come from inside science and the research world.
And that’s the same problem I see in most discussions of how scientists should communicate. The universe of ideas is restricted to those that originated in the sciences.
Creativity works. As Lillie points out, creative solutions can depend on using an effective formula -- and winning formulas already have millions of dollars of Hollywood money invested in them precisely because they work. Molière knew this, as have most serious writers and playwrights over the centuries.
One problem is that the humanities today don't teach this stuff to their students. The practical skills may be known among those who work in writing and entertainment, but they aren't known among those who study such things. Nor are they conveyed to science students in their humanities elective courses. Academic humanities have been far more about sociopolitics than skills.
That perspective dominates a recent piece by Simon During: Stop Defending the Humanities".
The humanities join the wider world in other ways. They belong to an economy of prestige that helps prop up class and ethnic hierarchies. Forty or so years ago, Pierre Bourdieu presented a complex, evidence-based theory of how this economy then worked in France. His findings may now be partly out of date, but surveys since have routinely found that those who study the academic humanities disproportionately belong to the white upper-middle class, i.e., those with significant inherited cultural and economic capital. In this situation, those humanities disciplines that have emerged in relation to newer technologies and social movements tend to have less status, and to be taught in different kinds of institutions and through different methods and theories, than the core humanities, part of whose purpose remains to reproduce certain bourgeois sensibilities and cultural capital.
Reading this essay about the academic humanities, you will wonder how any students learn how to write by taking courses in these fields. The answer is that they don't -- in fact, at my university most science students learn their writing in science courses.
In During's description, the humanities for better or worse are like "a world alongside similar worlds", a way of seeing (and reading) things that necessarily entails a frame of reference, a perspective -- he doesn't say this, but a theory in the modern sense used in humanistic writing.
Under this "world apart" definition, what the academic humanities may not be doing is teaching students how to communicate, how to frame arguments, how to be informed citizens or to be self-critical about their construction of knowledge. This is another case of academics thinking that the facts known inside academia are the only ones relevant to a problem.
David Balding and Mark Thomas, two professors at University College London, have been the objects of a series of legal threats from the company BritainsDNA. They have maintained a journal of their activities in this case, which is online at the UCL website: "A tale of misleading claims and legal threats".
The threatened legal action came in response to written questions that Balding and Thomas posed to representatives of BritainsDNA. The precipitating event was a July 2012 BBC interview with Alistair Moffat, a principal in BritainsDNA, in which Moffat claimed various things about DNA in human ancestry. Balding and Thomas wrote emails to Moffat and other scientists associated with BritainsDNA criticizing several statements that were wrong according to currently accepted science. The resulting email exchanges resulted in a series of legal demands by lawyers representing BritainsDNA. The entire saga should be read and examined closely by those working in anthropological and human genetics.
The linked page contains the current status of the story:
There has been a limited retraction of some of the false statements in the radio interview. In particular, the claim that the BritainsDNA service is "massively subsidised" was eventually admitted to be false, after many months and repeated requests for clarification, but only on the Genomes Unzipped website and not on the BritainsDNA website, which is where listeners who heard the false claims were directed. While making some welcome corrections on Genomes Unzipped, Jim Wilson introduced new falsehoods that have not been retracted. The legal threat and its untrue claims made by BritainsDNA against DJB and MGT have not been retracted. The misleading claims in BritainsDNA press releases have not been rectified. While complaints have been upheld against Mr Moffat by St Andrew's University and, eventually, the BBC, he seems to have done little to redress the problems that caused the complaints.On the positive side, the flow of exaggerated claims and media manipulation from BritainsDNA seems to have moderated: there seem to be fewer outlandish claims about being related to famous historical figures or descended from slaves, chiefs, queens, warriors, etc. (But it has not ceased, there was more nonsense in the Daily Mail in February 2014.) Whether the moderation is in response to criticism or because the BritainsDNA PR goals have been achieved remains unclear. According to Debbie Kennett the new tests offered by BritainsDNA are better, and the interpretations of the results may have also improved.
This is an important case for those of us who write about genetic testing and the claims of genetic genealogy services. The threat of being drawn into costly legal proceedings is real, and inhibits many honest commentators from investigating the services being advertised by such companies.
Anyone interested in the field of genetic genealogy should read through Balding and Thomas' experiences.
While BritainsDNA must bear responsibility for their actions, the role of their lawyers in exacerbating the problem should not be overlooked. DJB and MGT have been informally advised by those familiar with libel threats that the letter they received (see 3/9/12 on the timeline page) was among the worst, and represented low professional standards. It was foreseeable that making legal threats against academic colleagues to try to silence their criticisms would create considerable damage to the reputation of BritainsDNA. No reasonable person could have expected the threatening letter to achieve its stated objectives, and the risks to the company from its provocative language and unreasonable demands must have been obvious.
Through my website, I have heard from more than a hundred customers of genetic genealogy services during the last year, most of whom had received misleading information, or information at variance with the current scientific publications on their specific questions. (None of these have asked questions about BritainsDNA, which is trying to serve a particular niche that I don't cover).
In my experience none of the companies reporting genetic genealogy information currently do a good enough job of it. Many reports are misleading, especially given the level of previous education among customers.
The geneticists who have gone into consultancy with private companies have a wide range of different experiences and perspectives. Their experience and ability to accurately describe results varies widely.
This paragraph from Balding and Thomas' letter to Moffat is worth quoting in full, I endorse it completely:
The public has a great appetite for stories about its ancestry from DNA data, and this provides a very strong commercial incentive to cut corners, exaggerate beyond the evidence, and ignore uncertainty. Such misleading practices are aided by the fact that, since there is very little that can be proven about an individual's ancestry from, say, mtDNA or Y polymorphism data, it is equally difficult to prove that any specific claim is false. However, we have had direct experience of disappointed customers who, once it is explained to them that the genetic ancestry results for which they have paid a substantial sum cannot be confirmed scientifically, become disillusioned with science more generally; they previously believed that scientists could be trusted.
Chris Mooney reviews the book, Our Political Nature: The Evolutionary Origins of What Divides Us by Avi Tuschman, in an article in Washington Monthly: "The Origin of Ideology".
Some writers seem highly invested in the idea that political beliefs are affected by genetics. I am very skeptical of this genetic determinism. Usually an appeal to genetics serves as a convenient way to demonize critics.
At any rate, I point to the review because it enlists the Neandertals as pawns in the grand scheme of the evolutionary history of political nature:
The more you think about it, the more mind-boggling it is that this cross-species mating actually occurred. Imagine how strange it must have been, as a member of Homo sapiens, to encounter another being so closely related to us (much more closely than chimpanzees), and yet still so different. J. R. R. Tolkien buffs can probably visualize it the best, because it would indeed have been something like humans encountering dwarves. Neanderthals were shorter and stronger, with outjutting brows. There is some evidence suggesting that they had high-pitched voices and red hair.
Knowing how prevalent racism and xenophobia are today among members of the same human species, we can assume that many of our ancestors would have behaved even worse toward Neanderthals. And yet some Homo sapiens bred with them, produced offspring with them, and (presumably) cared for those offspring. Which ones were the lovers, not the haters?
The answer, hints Tuschman in Our Political Nature, is that it may have been the liberals.
That's right. Lyndon Johnson of the Pleistocene, sexing it up with thick-browed women.
Then there's Bill Clinton...well let's let him speak for himself:
“We learned in the last few months, because of the Human Genome Project, which I spent a lot of your tax money on to finish, that . . . between 1 and 4 percent of your genome comes from our pre-human ancestors the Neanderthals. Now it didn’t surprise my wife and daughter to learn that I was part Neanderthal.”
Oh, Bill, you ain't nothing but a hound dog. It's a good think Hillary's politics allowed her to mate outside her group!
Jean Combier and Guy Jouve report in L'Anthropologie that the art of Chauvet Cave has been misdated: "New investigations into the cultural and stylistic identity of the Chauvet cave and its radiocarbon dating". The paper is in French, but here is the English abstract:
The discovery of Chauvet cave, at Vallon-Pont-d’Arc (Ardèche), in 1994, was an important event for our knowledge of palaeolithic parietal art as a whole. Its painted and engraved figures, thanks to their number (425 graphic units), and their excellent state of preservation, provide a documentary thesaurus comparable to that of the greatest sites known, and far beyond what had already been found in the group of Rhône valley caves (Ardèche and Gard). But its study – when one places it in its natural regional, cultural and thematic framework – makes it impossible to see it as an isolated entity of astonishing precocity. This needs to be reconsidered, and the affinities that our research has brought to light are clearly incompatible with the very early age which has been attributed to it. And if one extends this examination to the whole of the Franco-Cantabrian domain, the conclusion is inescapable: although Chauvet cave displays some unique characteristics (like every decorated cave), it belongs to an evolved phase of parietal art that is far removed from the motifs of its origins (known from art on blocks and on shelter walls dated by stratigraphy to the Aurignacian, in France and Cantabrian Spain). The majority of its works are therefore to be placed, quite normally, within the framework of the well-defined artistic creations of the Gravettian and Solutrean. Moreover, this phase of the Middle Upper Palaeolithic (26,000–18,000) coincides with a particularly intensive and diversified local human occupation, unknown in earlier periods and far less dense afterwards in the Magdalenian. A detailed critique of the treatment of the samples subjected to AMS radiocarbon dating makes it impossible to retain the very early age (36,000 cal BP) attributed by some authors to the painted and engraved figures of Chauvet cave.
By far the largest proportion of art in caves of France and Northern Spain is relatively late in time, dating to Magdalenian peoples after 18,000 years ago. But caves were not closed systems, and a number of them have art pieces that date into earlier Solutrean or even Gravettian times.
Every expert agrees that the extensive panels of art in Chauvet are extraordinary. Some believe that they reflect a stylistic tradition of much later people, sharing with caves like Lascaux, Altamira and Font de Gaume. Others have been more willing to accept that the artistic tradition at Chauvet was developed largely independently from the traditions recorded in later caves. These have argued that it is the oldest instance of cave art (called parietal art) in the world.
They have been supported by radiocarbon dating. The dates for charcoal in the Chauvet paintings are more than 30,000 years ago, with four different paintings generating radiocarbon ages between 30,000 and 33,000 years BP. But dating of paintings is a specialized affair. Charcoal is not the best material for dating to begin with, the presence of very thin layers of charcoal in association with damp cave walls, mixed with other pigments, makes matters worse. Combier and Jouve note that some charcoal drawings have given substantially more recent dates than the paintings.
Combier and Jouve favor resolving the discrepancy between these dates by accepting that the paintings involve carbon from charcoal mixed with substances that include carbon from older sources, such as minerals. They base their strongest argument on the similar case of Candamo cave in Spain, where the stable isotope ratio of carbon-13 to carbon-12 in the paintings varies substantially from that expected from wood charcoal. In that case, there is a similar divergence of dates from different figures. The figures with older dates apparently had a diagenesis in which bacteria incorporated older carbon from the cave walls into the pigment samples. Although such an analysis has not been done for Chauvet, the authors advocate examining the radiocarbon samples again with this possibility in mind.
Ultimately, Combier and Jouve reject the stylistic arguments for an Aurignacian age of the Chauvet paintings. They conclude:
We have examined rationally all the statistics that have been presented to justify an Aurignacian age for the Chauvet art, that have hoped to show it as the oldest parietal art in the world, but we found no scientific evidence to justify dates older than the Gravettian, and these relate exclusively to identified charcoal ensuring their reliability. We note that proving a Gravettian age for some drawings still places the Chauvet art as among the oldest in the world, but it is not Aurignacian.
They additionally note that there is widespread evidence for human occupation in the region in Gravettian and later times, but much less evidence for Aurignacian-era occupation. That circumstantial evidence is less persuasive, but it does adjust the prior probability on the calculation as to whether people were more likely to use the cave earlier or later in time.
The paper presents a solid case for skepticism about the age of the Chauvet paintings.
Combier, J and G. Jouve. 2014. Nouvelles recherches sur l’identité culturelle et stylistique de la grotte Chauvet et sur sa datation par la méthode du 14C. L'Anthropologie (in press) doi:10.1016/j.anthro.2013.12.001
Colleen Morgan has a new post at Middle Savagery that may serve as an intervention to those who claim that archaeology isn't a romantic field: "Stop saying 'Archaeology is actually boring'".
As more and more archaeologists become involved in science communication, whether by blogging, or television, or public lectures we cannot have the same failures over and over (and over) again. By calling archaeology boring you are not serving an important function in rectifying pop-culture. You are not imbuing your work with some kind of scientific importance. You are not showing a reaction against positivism with your post-modern indifference. You are stealing the limelight from the parts of your research that are absolutely fascinating. You are diminishing the reasons you became an archaeologist, and the reasons that you are compelled to tell people the story of your research.
I agree. I mean, what do teachers think they are doing when they say this stuff? Are they afraid that people will think archaeology is just like it looks in the movies?
News flash: Your students already know that movies are not reality.
And if they do think movies are reality, they probably think you are the pompous literature professor from Back to School. I mean, do economics teachers need to tell their students that economics is actually boring? "It's not all like The Wolf of Wall Street, you know!"
I have had a wonderful experience seeing students in my massive open course react to our student field journals. The graduate students have some outstanding videos that they edited, showing their experiences working in the field last summer at Swartkrans, South Africa and Olduvai Gorge, Tanzania. They show the reality of fieldwork, from the painstaking excavation process to the realities of life in camp. Many of the worldwide students have been fascinated to see this work behind the scenes. A few have been amazed at how little return there is to these field operations, very small moments of discovery within a long, tedious period of working. Only a handful of students have said that fieldwork is boring. And that's because it isn't -- it's work, not boring work!
In an open access article in PLoS ONE, Ruggero D'Anastasio and colleagues take a closer look at the internal structure of the hyoid bone from the Kebara 2 Neandertal skeleton. The abstract is very straightforward:
The description of a Neanderthal hyoid from Kebara Cave (Israel) in 1989 fuelled scientific debate on the evolution of speech and complex language. Gross anatomy of the Kebara 2 hyoid differs little from that of modern humans. However, whether Homo neanderthalensis could use speech or complex language remains controversial. Similarity in overall shape does not necessarily demonstrate that the Kebara 2 hyoid was used in the same way as that of Homo sapiens. The mechanical performance of whole bones is partly controlled by internal trabecular geometries, regulated by bone-remodelling in response to the forces applied. Here we show that the Neanderthal and modern human hyoids also present very similar internal architectures and micro-biomechanical behaviours. Our study incorporates detailed analysis of histology, meticulous reconstruction of musculature, and computational biomechanical analysis with models incorporating internal micro-geometry. Because internal architecture reflects the loadings to which a bone is routinely subjected, our findings are consistent with a capacity for speech in the Neanderthals.
Those of us who remember the 1990s will remember the silly arguments that arose about whether the morphology of the Kebara hyoid was really humanlike, or whether anyone could even tell humanlike from apelike morphology. One specialist shamefully reported that pig hyoids resemble humans moreso than the Kebara 2 hyoid does.
Thank goodness those dark days have passed and everyone now acknowledges the behavioral sophistication of the Neandertals!
I'm far more likely to be critical of a different issue: the identification of the Kebara 2 skeleton as a Neandertal.
Sure it is robust in its upper limb morphology; it has a long pubic ramus, and it has a mandible with no distinct chin and a retromolar space. Those are all similarities with European Neandertals. But are those features enough to diagnose it as a Neandertal?
Many other specimens from Israel have been called Neandertals, such as the Tabun 1 and Amud 1 skeletons, but they don't have the same combination of features as European Neandertals. Amud 1 in particular shares only a relative handful of characteristics with Neandertals, meanwhile it has a chin and limbs that make it taller than any other Neandertal skeleton. The Kebara skeleton is a striking specimen, but it actually presents less evidence for Neandertal affinities than these other specimens. It is missing its cranium and lower limbs, leaving mainly the mandible and thorax as evidence for Neandertal similarity.
Initially, physical anthropologists considered the Levantine samples of ancient humans to represent a mixture of Neandertal and modern traits. The interpretation of this mixture has changed over time. McCown and Keith suggested that the population was one "in the throes of evolution" from a more modern-like form to a more specialized, Neandertal-like form. Dobzhansky argued that the population was a hybrid mixture of Neandertal and modern ancestors. Later, Howell argued that the Skhul sample were possible ancestors for the early Upper Paleolithic people of Europe, "proto-Cro-Magnons". This latter characterization is the one that has been repeated most widely, but not without dissenters.
We now know from genetics that the population we have been calling "Neandertals" across western Eurasia was much more genetically diverse than has often been assumed. At least one Neandertal population mixed into the ancestral population of present-day Eurasians and North Africans. Other apparent Neandertal populations were at least as different from each other as any of today's Eurasian populations are from each other. We have no ancient DNA evidence at all from Israel, either from specimens widely considered "anatomically modern" or from those considered to be Neandertals.
Maybe that Levantine fossil sample represents a very different population from European or Central Asian Neandertals. Or a substantially mixed population. Or a population with North African roots that bears similarities with modern humans because of ancient gene flow within Middle Stone Age Africans. Or...
...or any number of things. I suggest that dichotomizing this fossil sample into Neandertal and modern moieties is oversimplifying matters. The fossils stretch for more than 40,000 years, maybe more than 60,000 years, from the Tabun skeleton, through Skhul and Qafzeh up to Kebara and Amud. The genetics now suggest that Europe, Central Asia, and South Asia saw multiple complex dispersals of people across much less time than this. Why would we assume that the crossroads of African and Eurasian peoples was like slow-motion trench warfare for 60,000 years?
The hyoid at least is clear. This skeleton belonged to an individual who used his throat in ways that involved similar forces on the hyoid as exerted by modern language speakers.
Arensburg, B., Tillier, A. M., Vandermeersch, B., Duday, H., Schepartz, L. A., & Rak, Y. (1989). A Middle Palaeolithic human hyoid bone. Nature, 338(6218), 758-760.
Arensburg, B., Schepartz, L. A., Tillier, A. M., Vandermeersch, B., & Rak, Y. (1990). A reappraisal of the anatomical basis for speech in Middle Palaeolithic hominids. American Journal of Physical Anthropology, 83(2), 137-146.
D’Anastasio, R., Wroe, S., Tuniz, C., Mancini, L., Cesana, D. T., Dreossi, D., ... & Capasso, L. (2013). Micro-Biomechanics of the Kebara 2 Hyoid and Its Implications for Speech in Neanderthals. PloS one, 8(12), e82261.
Leakey, Tobias and Napier (1964) defined the species, Homo habilis. A simple species diagnosis was not enough: Leakey and colleagues had to argue for an expanded definition of our genus Homo that could accommodate the set of very primitive skeletal remains from Bed I and Bed II of Olduvai Gorge.
It has long been recognized that as more and more discoveries were made, it would become necessary to revise the diagnosis of the genus Homo. In particular, it has become clear that it is impossible to rely on only one or two characters, such as the cranial capacity or an erect posture, as the necessary criteria for membership of the genus. Instead, the total picture presented by the material available for investigation must be taken into account.
This paper was the first and last formal attempt to expand our genus based on morphological considerations. That makes it a very important document in considering how we currently apply the genus concept to human evolution.
Consider the famous simplification of hominin taxonomy proposed by Ernst Mayr. Mayr argued that Homo should be expanded in usage to encompass the entire hominin fossil record -- from "Homo africanus" to Homo erectus to Homo sapiens. That taxonomic simplification in the heyday of the Modern Synthesis was in fact what gave us Homo erectus in the place of Pithecanthropus and Sinanthropus. That is, Mayr really did expand the genus Homo beyond its earlier and traditional usage. He did not do so by mounting a morphological argument but instead a phyletic one -- Homo in his conception was simply a name that encompasses the human lineage. Later, Morris Goodman would go further based on analogy with the level of genetic divergence found in genera of mammals more generally, urging that chimpanzees and bonobos be admitted to Homo as well. These arguments both are fundamentally cladistic, but not specifically diagnostic. In both cases, the solution for Homo is simply to eliminate Australopithecus and every other genus of hominins.
Leakey and colleagues faced the more difficult task of outlining a principled way to separate Homo from Australopithecus based on morphology.
The Olduvai sample gave them two big challenges. First, the brain sizes represented by OH 7, OH 13 and OH 16 are substantially smaller than those known at the time for Homo erectus. Further, the endocranial volume of the robust OH 5 craninum approaches these Homo-like specimens. Brain size no longer seemed a suitable criterion, at least not by itself. With any closely related taxa, it is inevitable that most characteristics will overlap in range, probably extensively. If we attempt to separate early Homo from other hominins based on brain size only, we will have to exclude small specimens (like KNM-ER 1813) or include large australopithecines (like OH 5). Although it is conceivable for a character to have a truly disjoint distribution (like tiger stripes versus lion manes), we should not expect to find such a character in a limited sample of fossil evidence.
Second, the sample included skeletal parts -- notably the hand and foot -- that were not previously well represented in fossil Homo or Australopithecus. Leakey, Tobias and Napier had the luxury of looking beyond the skull and teeth, for the first time incorporating them into the morphological diagnosis of our genus. But they had no way to ascertain whether these features were really diagnostic beyond their Olduvai sample.
In other words, they were forced to abandon the one traditional feature of Homo erectus relative to Australopithecus, the brain. They had the opportunity to add features that had not previously been important in the definition of Homo species, in particular the hand and foot. But those features were not at the time well evidenced in early hominins. So they proposed a combination of features as the essential qualities of our genus.
Reading through their paper today, it is striking how the fossil record has changed. I thought it would be useful to annotate their definition from 1964 with notes about how today's fossil record has (mostly) made it obsolete.
In some cases I've drawn from descriptions of later specimens, especially those carried out by Wood (1991). Wood would later (Wood and Collard 1999) mount an argument that none of the fossils attributed to Homo habilis or Homo rudolfensis should really be placed in Homo, but should instead be assigned to Australopithecus. I'll return to that argument later, but for the moment am just using the best descriptions of these Koobi Fora specimens to focus on how their anatomy contributes to an understanding of Leakey, Tobias and Napier's definition of Homo.
Revised diagnosis of the genus Homo. A genus of the Hominidae with the following characters: the structure of the pelvic girdle and of the hind-limb skeleton is adapted to habitual erect posture and bipedal gait;
We now know that this criterion does not separate Homo from earlier hominins.
the fore-limb is shorter than the hind-limb;
the pollex is well developed and fully opposable and the hand is capable not only of a power grip but of, at the least, a simple and usually well developed precision grip;
The Hadar hand remains are capable of a simple precision grip, and the Malapa MH 2 hand remains are certainly capable of a well developed precision grip. Indeed, MH 2 has a more human-like wrist morphology in some respects than does the OH 7 hand. So as we know it today, the hand of Australopithecus would qualify as Homo under this definition.
the cranial capacity is very variable but is, in the average, larger than the range of the capacities of members of the genus Australopithecus, although the lower part of the range of capacities in the genus Homo overlaps with the upper part of the range in Australopithecus; the capacity is (on the average) large relative to body-size and ranges from about 600 c.c. in earlier forms to more than 1,600 c.c.;
Cranial capacity is still the definition of Homo in practical terms. Most of the debate about whether early specimens can be attributed to Homo has revolved around what we know (or don't know) about the size of their brains.
But things have changed to some extent since 1964. The Dmanisi sample of Homo erectus includes three specimens with cranial capacities that are 600 ml or less, including the robust D4500 skull with a volume of around 550 ml. Since 1964, a broader sample of hominin fossils from East Africa have been referred to Homo habilis by one or another anthropologists. These include KNM-ER 1813, with a volume of only slightly more than 500 ml.
the muscular ridges on the cranium range from very strongly marked to virtually imperceptible, but the temporal crests or lines never reach the midline;
This is basically saying that some skulls of Homo are very robust in muscle markings and attachment and others are not, with the exception that there should never be a sagittal crest. We can set aside as exceptions a very small fraction of modern human skulls in which the temporal lines do meet at the midline. The main effect of this restriction in the definition is to exclude KNM-ER 1805, a skull that has some Homo-like features and that Bernard Wood (1991) assigned to the genus Homo, but that has a clear sagittal crest.
the frontal region of the cranium is without undue post-orbital construction (such as is common in members of the genus Australopithecus);
Together with the insistence on temporal lines that do not meet, this emphasizes a relation in which the brain is relatively large and the jaw muscles relatively small in proportion to each other. That is a tricky one only at the boundary of small brain size; however in reality the postorbital constriction present in specimens like MH 1 or even Sts 5 is not too extreme to fit into Homo, at least as represented by KNM-ER 1813 -- or even the much larger but similarly shaped OH 9 cranium.
the supra-orbital region of the frontal bone is very variable, ranging from a massive and very salient supra-orbital torus to a complete lack of any supra-orbital projection and a smooth brow region;
That's our second "very variable" qualifier. This is a problem character. Obviously a supraorbital torus is rare in living humans, but has been nearly universal in many ancient populations of Homo, including some that are uncontroversially recognized as Homo sapiens. So the trait has to be variable.
But at the earliest end of the fossil sample attributed to Homo, we also have that variation. KNM-ER 1470 has no supraorbital torus. KNM-ER 1813 does have a clearly marked one with a supratoral sulcus above it, one of Wood's (1991) strongest arguments placing it into Homo instead of Australopithecus. The supraorbital torus of MH 1 contributes to its Homo-like appearance and is a derived similarity with Homo in the comparisons carried out by Berger and colleagues (2010).
the facial skeleton varies from moderately prognathous to orthognathous, but it is not concave (or dished) as is common in members of the Australopithecinae;
Together with the supraorbital region and the occipital region, the face bears a great deal of weight in assignment of fossils to Homo. Leakey, Tobias and Napier adopt a conservative definition here. Homo does not have a dish-shaped or concave face. That excludes most of the australopithecines that were then known. But none of the Olduvai sample that Leakey, Tobias and Napier considered in this 1964 paper had enough facial skeleton to assess these aspects of their shape. OH 13 has maxillary remains but none of the upper face or nasal region.
Ironically, a specimen found later at Olduvai and assigned to Homo habilis after its discovery, OH 24, has a face with a concave profile -- although in reconstruction, the face is not concave transversely (side-to-side), but only sagittally, with a flat or slightly concave nasal region and moderate subnasal prognathism.
the anterior symphyseal contour varies from a marked retreat to a forward slope, while the bony chin may be entirely lacking, or may vary from a slight to a very strongly developed mental trigone;
This isn't very helpful; not clear that Sts 52 or even Early Pliocene mandibles like KNM-KP 29281 would be excluded from Homo by this definition. It is only expressing that Homo is variable. This definition is no help at all for contentious cases like KNM-ER 1802, or Omo 75-14, or the Uraha mandible.
It might be more helpful to consider the exact angle of the symphysis or its curvature, or to add that Homo lacks some degree of posterior buttressing of the symphysis present in many mandibles of Australopithecus. But the practical problem is differentiating early Homo from robust mandibles on the one hand -- which are more vertical in symphyseal profile and have a thick, tall corpus -- from earlier hominins on the other hand, which have a sloping symphyseal profile and often match OH 7 in corpus dimensions.
Leakey, Tobias and Napier concentrated most closely on the dentition, which would become crucial to understanding OH 7. The dentition is the clearest anatomical region in which these authors expanded the definition of Homo in order to accommodate their concept of Homo habilis.
the dental arcade is evenly rounded with no diastema in most members of the genus; the first lower premolar is clearly bicuspid with a variably developed lingual cusp;
This corresponds to the full loss of a canine-P3 honing complex and the shift to a molar-like function for the P3. But already in 1964, that was already known to be true of mandibles assigned to A. africanus such as Sts 52 or MLD 2. And of course it would include A. boisei and A. robustus. From today's point of view, this form excludes some of the Hadar mandibles, which have strongly unicuspid and rotated P3s.
the molar teeth are variable in size, but in general are small relative to the size of the teeth in the genus Australopithecus; the size of the last upper molar is highly variable, but it is generally smaller than the second upper molar and commonly also smaller than the first upper molar; the lower third molar is sometimes appreciably larger than the second;
Much had been made of the taxonomic relevance of the size proportions of the molars. Generally in Homo erectus, the third molars were smaller than the second molars. The Olduvai adult dentitions, OH 13 and OH 16, had larger third molars on the bottom -- and in OH 13 these were markedly elongated. The type specimen of Homo habilis, OH 7, was a juvenile and did not have third molars. The upper dentition of OH 13 has smaller third molars than second molars and even first molars -- as stated here. But the OH 16 upper dentition has larger third molars; they are the broadest of the upper teeth and may be the largest (the first molars are more elongated but narrower).
Australopithecine dentitions almost universally have their third molars as the largest upper and lower teeth, and second molars as the next largest. In other words, the molars get larger further back in the dentition. As defined by Leakey, Tobias and Napier, Homo disrupts this relation.
in relation to the position seen in the Hominoidea as a whole, the canines are small, with little or no overlapping after the initial stages of wear, but when compared with those of members of the genus Australopithecus, the incisors and canines are not very small relative to the molars and premolars; the teeth in general, and particularly the molars and premolars, are not enlarged bucco-lingually as they are in the genus Australopithecus; the first deciduous lower molar shows a variable degree of molarization.
Of these, the most important is the buccolingual expansion of australopithecine molars and premolars relative to those in Homo. The Olduvai sample of Homo habilis has elongated molars mediodistally, enhancing this contrast with australopithecines, despite the overall similarity in size between the Olduvai teeth and A. africanus. In their definition of the species Homo habilis, Leakey, Tobias and Napier further note that the dimensions of the molars in Homo habilis fall within the ranges of both Australopithecus and Homo erectus.
What to make of this definition?
Later workers have largely been more restrictive rather than more expansive. Wood (1991) applied a more restrictive set of features as important to assigning Koobi Fora cranial specimens to Homo, emphasizing the basicranium, frontal and occiput. No one has made use of a more expansive definition based on postcranial evidence. Wood and Collard (1999) and Wolpoff (1999) both concluded that a principled division between Australopithecus and Homo could be defended on adaptive grounds only if "Homo habilis" and "Homo rudolfensis" were included in Australopithecus instead of Homo. That distinction in both cases did use postcranial features in addition to cranial features, which tended to restrict Homo to a smaller set rather than expand it to a broader one.
The definition proposed by Leakey, Tobias and Napier in 1964 is obviously unworkable today. Arguably, some of the ambiguity of the definition of Homo can be resolved by studying their definition of the species Homo habilis that directly follows. After all, they clearly believed it defensible to place the Olduvai fossils in Homo despite the problems that they note at the outset.
But really the problem is a phylogenetic one. There is no feature listed in their diagnosis of the genus Homo that is a shared derived feature of all the samples attributed to Homo, that is not also found in some samples attributed to Australopithecus or other genera. The example of MH 1 is instructive -- setting aside the cranial capacity of the specimen, its other features nearly all align with those ascribed to Homo by Leakey, Tobias and Napier. It is very difficult to include a specimen like KNM-ER 1813 without bringing in many other specimens of A. africanus by the same argument.
Leakey, L. S., Tobias, P. V., & Napier, J. R. (1964). A new species of the genus Homo from Olduvai Gorge. Nature, 202(4927), 7-9.
Wood, B. A. (1991). Hominid cranial remains. Koobi Fora research project, Vol. 4. Clarendon, Oxford.
Wood, B., & Collard, M. (1999). The human genus. Science, 284(5411), 65-71.
Wolpoff, M. H. (1999). Paleoanthropology. New York: McGraw-Hill.
Berger, L. R., de Ruiter, D. J., Churchill, S. E., Schmid, P., Carlson, K. J., Dirks, P. H., & Kibii, J. M. (2010). Australopithecus sediba: A new species of Homo-like australopith from South Africa. Science, 328(5975), 195-204.
Smithsonian is running a retrospective on the career of Carl Sagan, by writer Joel Achenbach ("Why Carl Sagan is truly irreplaceable"). The occasion is the upcoming premiere of the remake of Cosmos, the 1970's documentary series that made Sagan a household name.
He led a feverish existence, with multiple careers tumbling over one another, as if he knew he wouldn’t live to an old age. Among other things, he served as an astronomy professor at Cornell, wrote more than a dozen books, worked on NASA robotic missions, edited the scientific journal Icarus and somehow found time to park himself, repeatedly, arguably compulsively, in front of TV cameras. He was the house astronomer, basically, on Johnny Carson’s “Tonight Show.” Then, in an astonishing burst of energy in his mid-40s, he co-created and hosted a 13-part PBS television series, “Cosmos.” It aired in the fall of 1980 and ultimately reached hundreds of millions of people worldwide. Sagan was the most famous scientist in America—the face of science itself.
Now “Cosmos” is back, thanks largely to Seth MacFarlane, creator of TV’s “Family Guy” and a space buff since he was a kid, and Ann Druyan, Sagan’s widow. They’re collaborating on a new version premiering on the Fox Network on Sunday March 9. MacFarlane believes that much of what is on television, even on fact-based channels purporting to discuss science, is “fluff.” He says, “That is a symptom of the bizarre fear of science that’s taken hold.”
I think MacFarlane has it right. Very little science programming on television is either daring or inspiring.
It will be interesting to see how the new Cosmos does.
I imagine my static website for the past three weeks left many people wondering if the Science Cafe led to my untimely demise. "Who Sciences Harder" indeed!
After that event I left for Johannesburg, South Africa, where I was working at the University of the Witwatersrand on the fossil collection. I've been too busy to blog for two weeks.
Or, well, that's not precisely correct. I did post last week at the National Geographic Rising Star Expedition blog, describing our foray back into the cave system to investigate a second hominin-bearing locality: "Scientists Return to Explore a Second Fossil Chamber".
Most everyone following paleoanthropology by now knows about the chamber that produced more than 1200 numbered specimens. That chamber, inaccessible except through a very narrow 12-meter chute, was the focus of our expedition in November. Since then, a team of scientists from Wits University — including me for the last two weeks — has been working on those bones. Every site represented in the Wits collection has a number; for example, Malapa is site 88. Every specimen plotted by the advance team during our November expedition was tagged in the cave, and given a number beginning with UW-101, for University of the Witwatersrand, site 101.
Every specimen, that is, except for four.
In the final days of the expedition, Rick [Hunter] and Steve Tucker had gone looking through the cave system for more fossils. They found a second area with bones, which we designated site 102. On the last day of our November run, this became the second hominin-bearing locality in the system when Marina Elliott and Becca Peixotto brought out four bone fragments that we could diagnose as hominin.
Lee Berger and Alia Gurtov are really the heroes of this story from last week, which you'll read in that post. For me, I'm still taking baby steps at caving.
In the laboratory I'm a little more useful. It has been remarkable for me to work with the Rising Star material over the last two weeks. As the material came out of the ground last November we were naturally preoccupied by the work at hand, receiving and cataloging specimens, and doing basic osteology to identify them. What we did not get in the field was a good comparative overview of the collection.
That picture is only just beginning to emerge now. We still don't know what this is. And that is pretty awesome.
We have only been doing preparatory work for the May workshop, which will carry out the initial description of the collection. Planning for the workshop to describe the fossils is going quickly now and I'll describe some of that later.
In the meantime, I have been working over the last day or two to catch up with my ongoing massive course, Human Evolution: Past and Future. The course is now on week 5, reviewing the cultural development of Middle Pleistocene humans, the genetics of modern human origins and the mystery of the Denisovans. We have shown more than 240,000 videos, and have had nearly 30,000 posts and comments in the class forum. I have a lot of work to catch up on this week, but so far things seem to be going very well.
I'll be participating in a fun science outreach event this Tuesday, the Science Cafe at the Wisconsin Institutes for Discovery:
Everyone is welcome!
As 2013 slipped beneath the waves, The Guardian ran a long excerpt of a TEDGlobal talk by Benjamin Bratton: "We need to talk about TED". Bratton is a sociologist and design theorist at the University of California, San Diego. His talk was devoted to one central message: TED is itself "a recipe for civilizational disaster".
That seemed a bit extreme to me.
Still when I thought about it, the TED conference, its spin-off TEDx conferences, and the resulting series of short video lectures have not been especially kind to the science of human evolution.
I've had my own complaints about TED in the past, especially their promotion of pseudoscience ("Pseudoscience and TED"). Human evolution in particular has been poorly treated by the TED series. The top hits for "TED human evolution" are:
- A lecture by Juan Enriquez ("Will our kids be a different species?"). According to his Big Think page, Enriquez is currently managing director of Excel Venture Management, and "is recognized as one of the world's leading authorities on the economic and political impacts of life sciences." An excerpt:
Do we have any evidence that that is happening? Well let's take a look at something like autism incidence per thousand. Here's what it looks like in 2000. Here's what it looks like in 2002, 2006, 2008. Here's the increase in less than a decade. And we still don't know why this is happening. What we do know is, potentially, the brain is reacting in a hyperactive, hyper-plastic way, and creating individuals that are like this.
- A lecture by the late Elaine Morgan ("I believe we evolved from aquatic apes"). An excerpt:
I don't know quite where this diktat comes from. Somebody up there is issuing the commandment, "Thou shalt not believe in the aquatic theory. And if you hope to make progress in this profession, and you do believe it, you'd better keep it to yourself, because it will get in your way."
- A lecture by Harvey Fineberg, a medical ethicist ("Are we ready for neo-evolution?". An excerpt:
Who doesn't want healthier children? And then, that same analytic technology, that same engine of science that can produce the changes to prevent disease, will also enable us to adopt super-attributes, hyper-capacities -- that better memory. Why not have the quick wit of a Ken Jennings, especially if you can augment it with the next generation of the Watson machine? Why not have the quick twitch muscle that will enable you to run faster and longer? Why not live longer? These will be irresistible.
The fourth hit is for a TEDx talk by Graham Hancock, which has been removed by TED from its central YouTube channel. This was one of the targets of those who were agitated by the TED inclusion of pseudoscience content. TED opened a forum that allowed the public to weigh in with opinions about this talk and its removal: "The debate about Graham Hancock's talk".
It is not until the fifth video that we get a talk by an actual evolutionary biologist. This one is by Mark Pagel, who has done work on the evolution of languages and whether they follow similar patterns to evolution of populations: "How language transformed humanity".
This array is frankly depressing. No actual paleoanthropologists appear in the Google results in the first five pages. Five pages of TED paleoanthropology results, and no paleoanthropology!
Despite first appearances, TED has featured some very good paleoanthropology talks over the past few years. Louise Leakey gave a TED talk, as did Zeresenay Alemseged. David Lordkipanidze and Svante Pääbo gave talks at TED-affiliated events. Some of these can be found in the first couple of pages of search results for "human evolution" at TED.com, although none are in the Google results. Louise Leakey's talk is the first result on a YouTube search.
They're not hidden. They're just not well curated. TED is not directing people to good science content.
The TED phenomenon has had an interesting effect on the communication of science concepts to the public. Selected TED talks have been shown on television's Science Channel, and on commercial airline flights. They are ubiquitous on YouTube, and used in science classes around the world.
But TED videos have been accumulating now for years, and they're just piling up. Rarely does TED revisit the videos, update classics, add new content or context to the old ones. It's a catch-and-release program for 18-minute talks. Catch them on film, and release them to the wild.
Over time the talks have been skewed toward questionable subjects. Registration for the main TED conference itself is several thousand dollars, and the conference thereby selects an audience of people with several thousand dollars of disposable income, with a skew toward Silicon Valley (the T in TED is for Technology). Meanwhile, the TEDx spinoff conferences depend on the enthusiasm of their organizers, some of whom have selected "outside the mainstream" topics and quacks. Bratton summarizes this tendency:
Recently there was a bit of a dust up when TEDGlobal sent out a note to TEDx organisers asking them not to not book speakers whose work spans the paranormal, the conspiratorial, new age "quantum neuroenergy", etc: what is called woo. Instead of these placebos, TEDx should instead curate talks that are imaginative but grounded in reality. In fairness, they took some heat, so their gesture should be acknowledged. A lot of people take TED very seriously, and might lend credence to specious ideas if stamped with TED credentials. "No" to placebo science and medicine.
I don't agree with simply deleting talks from TED's stream. That doesn't do anything, really, since those talks are available from alternative sites. Blocking them does nothing but reinforce the "lone genius against the scientific establishment" myth. Curators of art museums don't throw fake artworks in the garbage, they use their collections to show fakes for what they are. Blocking the Graham Hancock talk did not reduce its influence.
TED finds itself in the uncomfortable position that some of its "ideas worth spreading" are bad ideas. Those bad ideas should be confronted with facts, immediately, so people who see the bad ideas can see the facts, too. Sometimes that will mean adding more commentary, more video, juxtaposing different speakers. Sometimes that will mean adding a "pop-up video" track pointing to relevant facts.
Obviously people who agree to give a TED talk don't expect their video to be presented five years later alongside all the facts that show they're wrong. Expecting that high standard would make it harder to recruit speakers. But the resulting talks would be a lot more accurate and representative of reality.
We should hear from more great paleoanthropologists. And TED should do much more to feature the great scientific talks they already have. Every talk should have more context alongside it. Have its ideas stood the test of time, or have they already been rejected or shown to be exaggerated? Let's learn from the exaggerations and distortions in some past talks, not sweep them under the rug.
Nautilus interviewed archaeologist Meg Conkey about her work, including the "Between the Caves" survey project in France, to establish the pattern of open-air occupation sites in regions mostly known for the ancient remains in caves: "The caveman's home was not a cave".
She describes the systematic survey of plowed fields in search of flint artifacts, and notes the rarity of discovery of actual occupation sites:
Then we discovered what we think is an open-air habitation site in Peyre Blanque, also in the Ariège region, on a ridge that’s never been plowed. We found artifacts eroding out of a muddy horseback-riding trail in the woods. The horses had stirred up the mud, and exposed some stone tools; now the site has yielded hundreds of them. We started excavating and found stone slabs, which we believe is a habitation structure in the open-air, probably from the Upper Paleolithic, about 17,000 years ago. We also found yellow, black, and red pigments, meaning ochre—powdered hydrated iron oxide—that early humans used for art and body art.
The interview gives some interesting perspective on what Paleolithic archaeologists mean when they use the term, "home", and how discoveries in caves have biased our intuition about the ancient landscape.
Another beautiful view from last week's travel in Ethiopia:
This explains a lot. Nobody likes lumpers:
Probably some large fraction of "splitter" is referring to lumberjacks.
In this week's Nature, Francis Collins and Lawrence Tabak have written a policy statement about the problem of biomedical research results that cannot be replicated by independent studies. Collins is the director of the U.S. National Institutes of Health, and the essay is an official statement of how the agency is attempting to reduce the incidence of sensationalized findings that do not have real clinical validity.
Science has long been regarded as 'self-correcting', given that it is founded on the replication of earlier work. Over the long term, that principle remains true. In the shorter term, however, the checks and balances that once ensured scientific fidelity have been hobbled. This has compromised the ability of today's researchers to reproduce others' findings.
Although Collins and Tabak do not cite his work, their essay is a response to the findings of John Ioannidis, who has famously claimed that most published research findings are false. The basic reason is statistics. In many fields, studies are published when the results accord with a statistical threshold (often a 1 in 20 chance of being produced by chance). But across a whole field, everyone is selecting just these results for publication while discarding results that do not meet this threshold. Consider two studies of exactly the same phenomenon. One reaches the 1-in-20 threshold and is published. The other fails to reach the threshold -- maybe the result could be obtained once in every two trials -- and is not published. If both results could be compiled together, the phenomenon would fail to meet the test. But only one of the studies is published; the other falls into obscurity. It may never leave the pages of the lab notebook. Indeed, the results may never really be compiled when it is clear they will be non-significant.
What happens with replication studies is that research groups suddenly have an incentive to publish negative results. They might have obtained negative results on many, many different phenomena, but those would not be interesting enough to publish. We wouldn't probably be too concerned about any single case. But across many, many different areas of science, it appears that replication studies are consistently failing to reproduce the effects claimed by prior research. That failure reflects a systemic bias in favor of publishing "statistically significant" results. "Significance" presupposes that the studies are independent, when in fact publication of studies across a field is highly non-independent.
The Economist published an informative article about Ioannidis' work last year, which is cited by Collins and Tabak: "Trouble at the lab".
The pitfalls Dr Stodden points to get deeper as research increasingly involves sifting through untold quantities of data. Take subatomic physics, where data are churned out by the petabyte. It uses notoriously exacting methodological standards, setting an acceptable false-positive rate of one in 3.5m (known as the five-sigma standard). But maximising a single figure of merit, such as statistical significance, is never enough: witness the “pentaquark” saga. Quarks are normally seen only two or three at a time, but in the mid-2000s various labs found evidence of bizarre five-quark composites. The analyses met the five-sigma test. But the data were not “blinded” properly; the analysts knew a lot about where the numbers were coming from. When an experiment is not blinded, the chances that the experimenters will see what they “should” see rise. This is why people analysing clinical-trials data should be blinded to whether data come from the “study group” or the control group. When looked for with proper blinding, the previously ubiquitous pentaquarks disappeared.Other data-heavy disciplines face similar challenges. Models which can be “tuned” in many different ways give researchers more scope to perceive a pattern where none exists. According to some estimates, three-quarters of published scientific papers in the field of machine learning are bunk because of this “overfitting”, says Sandy Pentland, a computer scientist at the Massachusetts Institute of Technology.
I worry about paleoanthropology. Traditionally, the field has been data-poor. There are only a handful of fossils that represent any particular anatomical detail in any particular ancient species of hominins. That makes for small samples. But because the field is of very high interest, many paleoanthropological papers can report negative results and still be publishable in relatively high-profile journals. Indeed, several of my own papers have been essentially based on negative results -- failure to disprove a null hypothesis, or failure to show significant change over time. Those results are interesting when we are trying to test the pattern of our evolution.
Today, ancient DNA has begun to provide vastly more data about some parts of our evolution. But comparing an ancient genome to the genomes of hundreds or thousands of living people is not straightforward. We require fairly sophisticated models to understand the evolutionary changes in these samples.
Models introduce the problem of overfitting. And models require assumptions, which are often hidden away in the supplementary information of high-impact papers. As we've seen recently, many of the initial conclusions about ancient genomes, made in the wake of the Neandertal and Denisovan discoveries in 2010, were overhyped. Along with some other anthropologists, I raised concerns about these at the time, pointing out which conclusions were very solid, and which other ones we should treat more cautiously. And I'll continue to do that. But many people who are applying sophisticated models to ancient DNA data are not quite so cautious -- they are looking for their publishable results. Negative results are, at the moment, less interesting or publishable in this field. I worry that the level of scrutiny at top journals may be relaxing.
Collins and Tabak are not concerned with paleoanthropology, they are interested in biomedical research. But many areas of human genetics face the same challenges as paleoanthropology -- a sea of new data, with new methods of analysis, and high-profile papers being published that heavily depend on models. They point out some of the problems of this environment:
Factors include poor training of researchers in experimental design; increased emphasis on making provocative statements rather than presenting technical details; and publications that do not report basic elements of experimental design. Crucial experimental design elements that are all too frequently ignored include blinding, randomization, replication, sample-size calculation and the effect of sex differences. And some scientists reputedly use a 'secret sauce' to make their experiments work — and withhold details from publication or describe them only vaguely to retain a competitive edge. What hope is there that other scientists will be able to build on such work to further biomedical progress?
I wish I had a "secret sauce"! In any event, the NIH has adopted a radical solution: Alter the format of the biosketch.
Perhaps the most vexed issue is the academic incentive system. It currently over-emphasizes publishing in high-profile journals. No doubt worsened by current budgetary woes, this encourages rapid submission of research findings to the detriment of careful replication. To address this, the NIH is contemplating modifying the format of its 'biographical sketch' form, which grant applicants are required to complete, to emphasize the significance of advances resulting from work in which the applicant participated, and to delineate the part played by the applicant. Other organizations such as the Howard Hughes Medical Institute have used this format and found it more revealing of actual contributions to science than the traditional list of unannotated publications. The NIH is also considering providing greater stability for investigators at certain, discrete career stages, utilizing grant mechanisms that allow more flexibility and a longer period than the current average of approximately four years of support per project.
I read that and said aloud, "What?" Talk about a toothless policy.
I don't understand why people who apply for federal research money don't have their funding revoked when they don't follow agency policies. If a lab publishes hyped research, the principal investigator should be downgraded for future funding decisions. If the lab doesn't archive data and make it available for replication, the lab should be downgraded for future funding decisions.
And if intervention at the level of the lab is not sufficient -- as for advanced PIs who may be on their last funding cycle -- then the university or research organization should be downgraded. Simple as that.
Fortunately, we don't have too many data sharing problems in paleoanthropology.
Collins, FS and Tabak, LA. 2014. Policy: NIH plans to enhance reproducibility. Nature 505, 612–613. doi:10.1038/505612a URL: http://www.nature.com/news/policy-nih-plans-to-enhance-reproducibility-1.14586