Friday, April 22, 2016

Paleoanthropology Society meetings 2016

I recently returned from Atlanta, which hosted the 2016 meeting of the Paleoanthropology Society. As usual, there were some really interesting talks, one of which (I hope) was a presentation I gave on behalf of my colleagues with some data we collected on stone raw materials in the Olduvai Basin. Here are my favorite talks as recorded in my notes:
  • The meeting's first presentation was by Catalina Villamil, a graduate student at NYU, who examined variability in the orientation of the foramen magnum across several groups of primates and marsupials. Basically, her analyses found that among primates a more anteriorly oriented foramen magnum tends to be associated with orthograde postures (that is, postures that involve a vertically oriented trunk) rather than bipedal locomotion. This is important since, as she and others point out, paleoanthropologists often look for an anteriorly oriented foramen magnum to identify bipedalism and, thus, a fossil's identification as a hominin. It appears, then, that this is not necessarily a very good indicator. This calls into question inferences for bipedal locomotion for fossils like Sahelanthropus, whose purported hominin status rests partly on foramen magnum location.
  • Michael Pante and his colleagues presented data from high-resolution 3D scans of experimentally produced stone tool cutmarks, carnivore tooth marks, and crocodile tooth marks. This is really important, as there has been a good deal of disagreement over the identification of surface modifications on fossil bones, largely because of a lack of consistency and precision among analysts in the definition of features used to differentiate marks created by various agents. Intriguingly, they suggest that some ancient marks that are thought to have been created by stone knives show similarities with crocodile marks. Theoretically, one could scan an unknown mark, compare it to the 3D structure of marks of known origin, and determine the "fit" of the two in order to make a probabilistic assessment. The only drawback, as Pante stated, is the time it takes to adequately scan the marks (24 hours in some cases). So, this method cannot yet be applied to whole assemblages. Regardless, I am in total agreement that this is the direction bone surface modification studies should be going and, at the very least, we should subject questionable marks (or extremely important ones−Dikika anyone?) to this sort of analysis. In a similar vein, J.A. Harris et al. reported on a Bayesian approach to identifying surface marks, which also produces a probability that a mark belongs in a specific category.
  • Several talks touched on stone tool production and/or use among modern humans and chimpanzees and their implications for understanding Paleolithic technologies. Susanna Carvalho summarized her team's work in Guinea on wild chimpanzee stone tool use. She reported, really interestingly, that young chimps start to learn nut-cracking by observing close kin (this makes sense as these are the individuals with whom they grow up), while older chimps slowly shift their observations to more skilled individuals. She also provided what I thought was a cool quote: [Chimpanzee] "tools are not modified prior to use, but by use." David Braun piggybacked nicely on this talk when he reported some fun experiments conducted with these same chimps. Some background: Dave has previously demonstrated that hominins at the ca. two-million-year-old site of Kanjera South (Kenya) were pretty "choosey" when it came to the types of rocks they used for stone tools. Specifically, it appears as if these hominins intentionally selected rocks for their durability (i.e., their ability to hold a sharp edge over time). Dietz Stout has documented a similar level of selectivity (in this case, for stone with little or no impurities) at the 2.6-million-year-old site of Gona (Ethiopia). While this implied some level of cognitive sophistication, Dave related to us that he was often asked how these hominins could have possibly known about such physical properties of stone; where they, in fact, the first engineers? To explore this further, he designed an elegant experiment in which he transported the same rock types being used by the Kanjera hominins a few thousand kilometers west for use by the chimps living at Carvalho et al.'s open-air laboratory in Guinea. They laid the stones on the ground and recorded the frequency with which they were chosen by the chimps for nut-cracking. They found that the chimps selected harder rocks for hammers (not too surprising) and a soft, chalk-like rock for anvils. This latter observation was mystifying at first−after all, wouldn't you want a hard rock on the bottom, too?−until it was realized that successive nut-cracking events with these more malleable stones eventually resulted in the production of a deep impression that prevented the nut from slipping out from under the hammer upon impact. Pretty cool. They also witnessed how juveniles tended to "recycle" tool sets from older, more experienced individuals (that is, they passively took control of hammers and anvils after they were abandoned by those who knew what they were doing), which essentially provided a mechanism for how knowledge of raw material characteristics could be transmitted within a group. The two major take-home messages here were: (1) the properties that we, as modern humans, think are relevant when selecting a rock for use as a potential tool are different than those identified by chimps (and presumably, ancient hominins), and (2) an awareness of raw material characteristics (hardness, durability, what have you) does not necessarily require extensive knowledge of stone engineering and/or geology, and this information can be transferred in an entirely passive manner. This runs counter to interpretations that consider selectivity and multi-stage reduction sequences among Oldowan hominins as evidence for sophisticated cognition and/or complex modes of learning (however, see here for an example of recent work indicating that active teaching was probably not necessary to transmit knapping skills). The last lithic paper I'll mention came from Nada Khreisheh, who reported that an individual's skill with handaxe production correlated best with psychometric tests that involve planning.
  • David Patterson, a graduate student at George Washington University and the person largely responsible for manning the laptop to ensure that everyone's PowerPoints loaded properly, produced some fascinating data on stable isotopes across the ancient landscapes of Koobi Fora (Kenya) between 2 and 1.4 million years ago. Tons of data here, but what I found to be most interesting was the observation that one of the only taxa in the Turkana Basin with a pattern of C4 enrichment was fossils of the genus Homo, which suggests that something special was going on with this bipedal ape over this time span: more C4 plants, or the consumption of C4-eating animals? This theme also appeared in a paper from Kay Behrensmeyer et al. who, in their analysis of the paleoecology and paleogeography of a slice within Koobi Fora's Okote Member (ca. 1.51-1.53 million years ago), found that hominins were so-called "transient" species−that is, they appear and then disappear within the sedimentary sequence. This could indicate that they utilized a greater diversity of habitats than other animals.
  • The last talk before lunch on the first day was given by Yohannes Haile-Selassie, who reported on a new species of australopithecine, Australopithecus deyiremeda and its implications for diversity within the hominin family tree during the Middle Pliocene. Full disclosure here: even though this species was announced over a year ago, I had never heard of it. This just goes to show how difficult it is to keep up with the literature with a heavy teaching load and (most importantly) a toddler. In fact, I have so little time to go through the newest primary literature that I depend on conferences like this and Texas A&M's fantastic Anthropology in the News feed for the latest in paleoanthropology. Anyway, Haile-Selassie suggests that the hominin phylogeny may be as diverse prior to three million years ago as it appears to have been after three million years ago.   
  • Behrensmeyer's presentation also criticized the use of the term "mosaic" in paleoecological reconstructions, mainly because it is so imprecise. Many of the reconstructions, including those from Amy Rector and colleagues for Cooper's D and Kay Reed et al. for the lower Awash valley, tend to converge on some sort of "mixed" habitat (usually between forest and bushland, or bushland and grassland). In these cases, though, the imprecision reflects the type of data (in this case, mammal fossil assemblages).
  • Darryl de Ruiter presented on the new Homo naledi assemblage on behalf of the Rising Star team. As in their recent publications, de Ruiter maintains that the most likely explanation is that the bodies were deposited intentionally by members of the group using the cave system as a grave site of some sort. John Shea suggested that the assemblage could represent young, adventurous males that became stuck within the depths of the cave. An interesting hypothesis, although de Ruiter pointed out that it appears as if the assemblage includes individuals of both sexes and all ages. No news on the age of the assemblage...this is going to be very intriguing for some time.
  • Because of my work in Armenia, my ears perked up during Simonyan et al.'s presentation (given by Miriam Belmaker) on test excavations in southern Armenia. They reported the recovery of a large assemblage of obsidian artifacts that show techno-typological affinities to the late Lower and Middle Paleolithic. Obsidan hydration dates (which, as Belmaker acknowledged, can be pretty temperamental) indicate at least two separate occupations, one at ~120,000 and the other >200,000 years ago. I look forward to hearing more about this as research progresses.   
  • My team, including my friends and colleagues Cynthia FademRyan Byerly, and Audax Mabulla and UNCG undergraduate researcher Curran Fitzgerald, presented on our recent work with lithic raw materials in the Olduvai Basin. Building on the work of folks like Dave Braun, we reported on data we collected with a Proceq Schmidt Rock Hammer, which, by measuring rock hardness, provides an objective and quantitative proxy for raw material "quality." These sorts of data are critical if we want to start understanding why hominins chose the rocks they did for tool manufacture. We also collected a ton of additional samples to determine if the handful of macroscopically similar, but spatially discrete, quartzite outcrops in the basin could be distinguished based on their elemental composition. Encouragingly, this does appear to be the case, which means that determining the source of the quartzite artifacts from the Olduvai archaeological sites is a real possibility.    
  • The most thought-provoking paper was given by Stanley Ambrose and his colleague Jibril Hibro. They argued that Neandertal-modern human admixture should not yet be viewed as a given. The weakest link in these studies is that African genetic diversity was woefully underrepresented, which means that genetic variants identified as deriving from Neandertals (or other archaic populations) could, in fact, have already been present (but unsampled) among African populations. So, the question that has not yet been adequately addressed is, as their paper's title suggests, Is Neandertal-human genetic admixture in Eurasians actually African ancestry? This paper certainly reminded me to be cautious in our interpretation of the genetic data.
  • The last paper I'll comment on was the very last of the conference, given by Randolf Donahue and colleagues. They introduced, which allows anyone to examine high resolution photos taken by drones around Lake Turkana for fossils and other items of paleoanthropological interest. This forms part of the "Citizen Science" movement, which attempts to harness the public to essentially crowd source the collection of data. I have looked at some of the photos myself and, even at relatively high resolution, it is not easy to pick out materials. Nevertheless, I am anxious to see how this project progresses...
Lots of other great papers, just not enough energy to write about them all. First trip to Atlanta, too...seems like it has a lot going for it.

Wednesday, March 9, 2016

Giving a talk at the Virginia Museum of Natural History

I am travelling to Martinsville, VA, tomorrow to deliver a talk at the Virginia Museum of Natural History. I was contacted a few months ago by the museum's executive director, Dr. Joe Keiper, to participate in their 2nd Thursday Science Talks program. This year's theme is "From Cosmology to Conservation: Your World and Your Place in It." In the spirit of that theme, I will be discussing what I think Neandertals can teach us about the concept of "Race" among modern humans. Here are the talk's particulars:
A Neandertal's Perspective on the Existence of "Races" Among Modern Humans
For many years, anthropologists have grappled with the central paradox of "Race". On the one hand, the nature of human variation seriously undermines the biological reality of racial categories. On the other hand, it is evident that one's race, as a marker of status, identity, or heritage, is real and, thus, really matters. In this presentation, we will step back nearly 35,000 years, when the last Neandertals roamed Ice Age Eurasia, to explore what these extinct humans can teach us about race and, ultimately, what it means to be human in today's world.
Looking forward to it! 

Friday, November 6, 2015

Paleolithic research in the Armenian Highlands and Anatolia

I returned safe and sound from Anakara a couple of weeks ago (an unexpected overnight stay in Terminal 5 at JFK not withstanding) and am happy to report that the trip was well worth it. It was an intimate event, with 14 papers and perhaps 20-30 audience members. Some highlights:
  • The first paper was by Amilié Vialet and her colleague M. Cihat Alçiçek, who discussed the Kocabaş skullcap. I was particularly interested to hear this talk, as I knew next to nothing about this important hominin fossil. The remains consist of the frontal and parietal of a hominin that were recovered in 2002 during quarrying activities in the travertines of the famous Pammukale (Turkish: "Cotton Castle") hot springs (and UNESCO World Heritage Site) in western Turkey. (I actually visited this area, which also includes impressive ruins from Greek and Roman times, on a vacation way back in 2001.) The top of the skullcap was literally shaved off by heavy equipment (unfortunately, the rest of the skull, nor any other part of the skeleton, have ever been recovered) but, thankfully, the recovered bones were brought to the attention of Alçiçek, who recognized their importance. John Kappelman and his colleagues had previously published on the remains and suggested that (1) they dated to ~500,000 years ago, (2) provisionally, they represented H. erectus; and (3) the individual suffered from the earliest known case of tuberculosis. Vialet (who, apart from being a world-class paleoanthropologist, is a genuinely nice person) summarized more recent work on the fossil. Perhaps most importantly, they push back the age of the remains using a variety of dating techniques to ~1.4 million years ago, which makes them among the oldest in all of Eurasia. An audience member asked Vialet about tuberculosis, and she vacillated, saying that a confident diagnosis from their team would need to await further analyses. Their 3D reconstruction of the cranium, however, suggested a closer affinity of Kocabaş to Homo ergaster fossils from Africa rather than early Homo (including the crania from Dmanisi) fossils or later, classic Homo erectus populations from Asia. Vialet suggested, then, that Kocabaş represents an "expansion [from Africa that is] different from that represented by the Dmanisi fossils". It is becoming increasingly clear that the movement out of Africa by hominins ca. 2 million years ago was a complex series of events (emphasis on the plural) that involved many populations, some of which were able to establish long-term occupations and others that quickly went extinct. The new information from Kocabaş certainly reinforces this idea.
  • What followed was a series of papers by our Turkish colleagues that summarized the Lower and Middle Paleolithic of Anatolia. What struck me is that apart from a few notable exceptions (Kaletepe Deresi 3, Karaïn Cave, Yarımburgaz Cave, and Üçazğlı Cave), much of what is known is based almost exclusively on surface assemblages that lack key contextual information (chronometric dates, paleoenvironmental reconstructions, etc.). For example, Kadriye Özçelik reported on surface surveys that documented for the first time the presence of Paleolithic material in the Denizli Basin of southwestern Anatolia (this is the same region in which the Kocabaş fossil was uncovered). It is quite amazing, if you think about it, that it took until 2014 to officially recognize the presence of Paleolithic tools in this region, especially since, as I later learned, handaxes have been known in Turkey since 1896. While those of us working in Armenia faced a similar situation−that is, a dependence largely on surface finds−a great deal of progress has been made on this front in the last 10 years, due largely, I think, to the support of the Armenian Academy of Sciences, which has done much to nurture Paleolithic research in Armenia. My conversations with Turkish researchers revealed that it is extremely difficult to acquire permits to even examine and collect surface assemblages in Turkey, much less excavate stratified sites. Until that changes, I fear that our knowledge of Paleolithic settlement in modern Turkey will continue to lag behind that of other nearby countries.
  • Our paper summarized work on Bagratashen 1, and we officially announced OSL dates from the Middle Paleolithic horizon of around 35,000 years ago. While Middle Paleolithic sites of this age are not unusual, the types of stone tools uncovered from the deposit look like artifacts from other parts of the southern Caucasus and the Levant that are much older, somewhere around 150,000 to 200,000 years ago (see my previous post on Bagratashen 1 here). So, either our dates are way out of whack (which is possible), or we have an example of technological convergence where culturally and temporally unrelated hominin groups independently converged on similar tool types. There is a long history in archaeology of viewing stone tools to track human populations. That is, particular cultures made particular types of tools, so if you find similar tools, you have the same people. However, folks have long pointed out that, as complex a technology that lithic manufacture can be, there are only so many ways that one can reduce a chunk of rock into different shapes. Dan Adler and his colleagues made precisely this point in their paper about their excavations at Nor Geghi 1 in Armenia. What they found is that at about 330,000 years ago, folks in Armenia were creating both bifacial artifacts typically associated with the Acheulean and Middle Paleolithic Levallois products at the same time. This shows definitively that, at least at Nor Geghi 1, making Acheulean bifaces has little to do with being part of an Acheulean "culture" that represents a particular group or species of hominins. Likewise, it seems that the appearance of Levallois technology, again at least in Armenia, need not necessarily represent a new group or species of hominin. Perhaps it is time, as Dan simulated with a humorous slide, to flush many of these stone tool "cultures" down the toilet.
I should also point out that Phil was able to bring together Turkish and Armenian researchers to discuss Paleolithic archaeology. This shows the power of science in general, and archaeology in particular, to transcend political and ethnic enmity and bring together people with common goals. I was honored to be part of such a momentous event.

Saturday, October 17, 2015

Off to Turkey!

I am leaving tomorrow for Ankara, Turkey, where my colleague Phil Glauberman has organized a workshop entitled "Palaeolithic Research in the Armenian Highlands and Anatolia". I am honored to be included in this event, which will bring together an international contingent of researchers that work on the Lower and Middle Paleolithic in a very under-appreciated and understudied region. I'll be presenting on our recent work at Bagratashen 1. It's been 15 years since my last visit to Turkey, so I'm looking forward to the trip. Check back soon for a post that summarizes the event...  

Tuesday, July 21, 2015

Society for American Archaeology meetings 2015

I attended the 2015 meetings of the Society for American Archaeology in San Francisco this past April (yes, again I am behind in my posts). Although I wasn't able to stay for the whole event, I did get a chance to see some really great talks. We presented a couple of posters on our recent work at Olduvai Gorge as well. As usual, I'll present the highlights from my notes:
  • Paul Goldberg and his colleagues provided some new geoarchaeological results from the important Paleolithic site of La Ferrasie (Dordogne, France). The Middle Paleolithic deposits at La Ferrasie, which date to between 90,000 and 45,000 years ago, represent one of the most important, and continuous, MP sequences in western Europe. Even more critically, several partial Neandertal skeletons were recovered from the site, most of them in 1909. One thing that I learned is that the cave is actually made up of two distinct areas, an eastern and western, both of which, as Goldberg and his colleagues showed, with different formational histories. What is more, the artifacts found within the cave's sediments were likely originally discarded somewhere else and only later washed in to their final location. Goldberg also talked a bit about La Ferassie 2, which is the partial skeleton of an adult whose exact provenience and age was still poorly understood. Although they were unable to relocate the exact find spot for this individual, they sampled some sediments from the original foot (currently housed in the Musée de l'Homme) and were able to match them to the sediments from their Layers 4-5, which are dated to around 45,000-50,000 years ago.
  • Probably the most fascinating talk that I saw was given by Thomas Morgan and his colleagues entitled "The social transmission of Oldowan lithic technology." They conducted an elegant experiment in which novice knappers were permitted to learn Oldowan lithic technology in one of four ways: (1) through reverse engineering (that is, by looking at finished products); (2) observation only (that is, by watching someone else create flakes without the benefit of active teaching); (3) simple, "ape like" teaching; (4) gestural teaching only (that is, being taught by an expert with gestures but no words); and (5) with fully verbal teaching. The results showed that novices created more, and more useful, flakes with the benefits of teaching, particularly verbal teaching. What intrigued me was that there was no evidence that observational learning was any better than reverse engineering. So, apparently, watching someone is no better than simply looking at finished products.
  • I attended a really fun session in honor of the 20th anniversary of the publication of Robert Kelly's "The Foraging Spectrum", which is a landmark book in the study of hunter-gatherers. Nick Conard and Britt Starkovich humorously critiqued the behavioral ecological approach championed by Kelly through, among others things, references to Jerry Garcia (you had to be there). Raven Garvey and Robert Bettinger presented a fascinating case study of two hunter-gatherer groups that, despite living in very similar environments (the subarctic and subantarctic), exhibited very different levels of technological complexity. They argued that culture, and the density of social networks in particular, encouraged (or discouraged) the invention, adoption, and spread of ideas. Thus, for them, ecological and adaptive factors can only go so far in explaining hunter-gatherer diversity. Mike Cannon and David Meltzer offered a mathematical model to explore foraging options when resources become limited. They asked, essentially, when, and under what circumstances, will a group of hunter-gatherers either (1) move on to use familiar resources elsewhere or (2) stay put and learn how to exploit new resources. The highlight of the session was, of course, Bob Kelly's reflections on writing the book. His story about the genesis of the title was especially interesting: he had decided on a title (I can't remember what he said it was now) but the Smithsonian Press had asked him to change it to something more catchy. He told this to his wife, who was flipping through a magazine at the time, and she came back with "Why don't you call it the 'Foraging Spectrum'"? The rest is, as they say, history!
  • Mathieu Lejay and his colleagues presented some data on Aurignacian-aged fireplaces from France. What I found interesting (and it makes sense once you think about it) was that their experimental work showed that bone-fed fires tend to be more bioturbated than wood-fed fires because of the increased organic content.
Overall, a really enjoyable meeting...

Back from the Gorge...

I returned from Tanzania last Thursday. We had another successful field season and another great group of students for the field school. Updates to come...

Tuesday, May 5, 2015

American archaeology in the 21st century

Every year we  present the Distinguished Alumni Award (DAA) to recognize graduates of the Department of Anthropology at UNCG. This year's winner was Lea Abbott, who is currently the Assistant State Archaeologist for North Carolina. Lea graduated from UNCG in the late 1970s, and his primary research interest is lithic technology. Our DAA committee, however, asked Lea to focus on the role of archaeology in the 21st century and the career prospects for our students, and he delivered with a great talk.

First, he summarized wonderfully the place that archaeology occupies in the broader context of humanity. Archaeology, according to Lea, is important because (1) it helps to round out history (he used the example of the Confederate surrender at Appomattox, as his talk was given on the anniversary, April 9th, of that seminal event in American history) and (2) it is the major venue by which the world's historic and prehistoric heritage is preserved (he mentioned the recent destruction of archaeological sites associated with unrest in the Middle East).

The students at the presentation were, unsurprisingly, also interested in jobs. Lea pointed out the intimate relationship between archaeology and development in the United States. Federally funded development projects require an assessment of the archaeological (or cultural) resources that may be impacted by the work, and there are many, many contract companies that provide this service. One only needs to drive down I-40 in North Carolina, Lea commented, to see new solar energy farms popping up, all of which required archaeological assessments prior to construction. This amount of work in cultural resource management rises and falls with the broader economy: lots of development, lots of archaeological jobs. Lea seemed to think that with the economy in an upswing the number of archaeology jobs for anthropology and archaeology graduates will be on the rise.

Lea also outlined some of the biggest issues that will confront the next generation of archaeologists. One of the most urgent is related to rising sea levels. There are, in North Carolina alone, ~5,800 archaeological sites that lie at or <30 feet above current sea level, and they are being eroded away at an alarming rate.

He concluded by offering some advice to students, particularly those who wish to pursue graduate studies. First, and most importantly, people who make a career of archaeology have to feel it not only "up here" (he pointed to his head), but "in here" (he pointed to his heart). If that doesn't apply to you, then archaeology is probably not a great career choice. Get engaged immediately, he also said, as professors have a lot going on, and students that are engaged tend to get great dissertation projects. He also recommended that students have a back-up. Take courses that will provide you with skills that can get you a job outside of archaeology.