How pathological is the Nariokotome Boy?

Regula Schiess and Martin Haeusler (2013) recently published a paper in the American Journal of Physical Anthropology that critically examines the issue of pathology for KNM-WT 15000 (the "Nariokotome Boy"). This analysis comes on the heels of other recent re-examinations of this important 1.5 million year old skeleton. For example, it was thought by many that the Nariokotome Boy, who died between the ages of 8-11 (based on tooth eruption and microanatomy) and 12-15 (based on bone development), would have attained an adult stature of perhaps 6'1" (185 cm). This suggested to many that a linear, heat-adapted physique was characteristic of Homo erectus. Graves and colleagues (2010) questioned this reconstruction, arguing that the individual would have largely finished growing, and that an adult stature of about 5'4" (163 cm) was closer to the mark (John Hawks, on his weblog, provides additional commentary here).

Several authors have suggested that Nariokotome suffered from growth pathologies that, if corroborated, would preclude the use of this particular skeleton as a reference for Homo erectus skeletal biology (things like maturation rate or stature). Schiess and Haeusler (2013) set out to test whether the skeleton possesses evidence for:

• Unusually small, platyspondylic (that is, flattened) vertebrae.
• Spina bifida, which refers to a series of conditions characterized by the failure of one or more neural arches to close and thus fully encircle the spinal cord.
• Condylus tertius, which is an additional condyle found on the anterior margin of the foramen magnum, right between the two occipital condyles.
• Particularly small spinal canals (spinal stenosis).

If present, this complex of symptoms could be linked to a rare growth anomaly that goes by the fun name of spondyloepiphyseal dysplasia tarda. To carry out the analysis, they compare KNM-WT 15000 to a reference sample of 63 modern humans of various ages (I suspect that since these are archaeological specimens, their ages were estimated, rather than known. The researchers get around this by lumping their sample into broad categories, juveniles, adolescents, and adults, rather than specific ages). So, they found that:

• KNM-WT 15000's vertebral heights are more-or-less what you'd expect for his age group (i.e., they are not pathologically flattened relative to modern adolescent humans).
• The skeleton's vertebrae (as measured by superior surface area) do in fact appear to be small.
• The non-sacral neural arches that are preserved show no evidence for non-fusion. The 3rd through 5th sacral elements are unfused (see below).

Sacral elements of KNM-WT 15000. From Schiess and Haeusler (2013: Figure 4).

• A condylus tertius is definitely present.
• KNM-WT-15000's spinal canals are very small compared to the modern reference sample.

Schiess and Haeusler (2013: 372) therefore conclude:

[T]he apparent flatness of the vertebrae is typical for the immature age of the Nariokotome boy. There is no indication for spina bifida sensu stricto. An extension of the sacral hiatus from S5 up to S3 is normal in humans of the same age as the Nariokotome boy. The condylus tertius is a developmental anomaly that is relatively common in the normal population unaffected by spondyloepiphyseal dysplasia tarda. It has no clinical relevance. Both the relative smallness of the vertebral bodies and a narrow spinal canal are not classic features of spondyloepiphyseal dyspasia tarda. The criteria for spinal stenosis are met in the cervical, but not in the thoracolumbar region. Moreover, pedicle and canal shape are not typical of congenital spinal stenosis. Rather, a comparison with other fossils suggests that a narrow spinal canal and small vertebrae might be specific to early hominins.

It would have been nice to have included individuals with these skeletal abnormalities in the reference sample; surely there is variation in how these conditions manifest (I'm not sure how difficult it is to get a hold of such specimens). Overall, however, they make a convincing case. All of this is not to say that the Nariokotome Boy was perfectly healthy. Schiess and Haeusler do note that the last two lumbar vertebrae are asymmetrical, likely the result of a severely herniated disc, which in turn probably caused a significant limp. Nevertheless, these findings show that the incongruities of the skeletal and dental age-at-death estimates are not the result of a developmental disorder and, further, that this wonderfully complete skeleton can still serve as a useful reference for Homo erectus skeletal biology.

References:

Graves, RR, Lupo, AC, McCarthy, RC, Wescott, DJ, Cunningham, DL (2010). Just how strapping was KNM-WT 15000? Journal of Human Evolution 59, 542-554.

Schiess, R, Haeusler, M (2013). No skeletal dysplasia in the Nariokotome Boy KNM-WT 15000 (Homo erectus) - A reassessment of congential pathologies of the vertebral column. American Journal of Physical Anthropology 150, 367-374.

Cultural misunderstandings: a case study from the British settlement of North America

I'm in the middle of reading Bernard Bailyn's latest book, The Barbarous Years: The Peopling of British North America: The Conflict of Civilizations 1600-1675, and I came across a very interesting example of two cultures talking past one another. A little background: the colony at Jamestown was founded in 1607, and over the next few years, colonists, including the now famous John Smith, undertook expeditions to map the area and to collect (or steal) provisions from the Indians (the colonists were in bad shape almost constantly during the first decades). As might be expected, both cultures were feeling each other out in order to maximize their respective advantages. On the one hand, while the Indians were interested in European trade goods, they wanted to constrain the colonists within small, coastal settlements focused on trade (rather than permanent homesteads). The Europeans were also looking to trade but, for myriad reasons, many where also looking to stay and settle permanently on land occupied by various tribes. Ok, I'll have Bailyn (2012: 57-58) pick it up at the point where he describes a cultural misunderstanding relating to power relationships (note the olde English spelling in the quotes):

In three days of elaborate ceremony and elusive conversation, fending off Powhatan's [a local chief] question of the colonists' purpose in settling, [John] Smith was urged, on behalf of his people, to acknowledge Powhatan 'as their lord' and to accept for himself the role of a subordinate chief. This, of course, to the extent that he understood the proposal, he ignored, but in the end, symbolically at least, he had no choice. After being feasted 'in their best barbarous manner' and treated like a defeated enemy about to be slain, he was brought to what appeared to be an execution block, surrounded by warriors 'ready with clubs to beate out his braines.' Then at the final moment he was suddenly released, adopted as a subordinate werowance, and by extension his people were symbolically enclosed within the constraints of Powhatan's regime. Never, of course, experiencing these events as acts of subordination, and declining the benefits offered, Smith recorded the story of his captivity at first briefly and with little drama (he 'procured his owne liberty'), then elaborated it in retelling, finally embellished it as an elaborate ceremony on the tale of how Pocahontas 'the King's dearest daughter' (who was eleven at the time) 'got his head in her armes, and laid her own upon his to save him from death.'

The parallel effort to subordinate and control barbarous and threatening people, at least symbolically, was played out reciprocally by the English the next year. Smith and Newport [describe him], on order from London, led a troop of musketeers to present Powhatan with a plethora of gifts, inlcuding copper objects, a bedstead and bedclothes  a red coat, and a copper crown, the last a gift heavily freighted with symbolism from the great King James. When with difficulty they managed to place the crown on Powhatan's forcibly bowed head, the ceremonial reduction of the chief of chiefs to the status of a vassal or local lord of King James was complete, symbolically confined within England's sovereign power.

In other words, both cultures carried out elaborate ceremonies that, while meant to subordinate each other, were perceived as meaningless rites because neither culture recognized them for what they were intended to be. The same thing happens all the time with modern cultures; sometimes these interactions can be humorous, but many times they can have serious, even tragic, consequences. For those who say that understanding other cultures is a waste of time, proceed at your own peril...

UPDATE 4.28.13

I've just finished the book, and it was a fascinating read. What struck me most was how heterogeneous the colonizing populations from Europe really were. Recent histories of colonial America have stressed, and correctly so, that Native Americans were not a single, monolithic unit but rather a diverse collection of rich cultures. So too for the incoming Europeans, whose various nationalities, religious views, and socio-economic circumstances determined to a great extent how they interacted with both native cultures and each other.

My Human Biological Variation class was recently engaged in a discussion about the biological reality of race among modern humans and, and it often does, the point that the concept's definition differs from place to place was raised. One student, originally from England, was surprised at how obsessed Americans seemed to be with their origins: people identify as African-American, German, Irish, Native American, and so on, while it is very rare for an English citizen to identify as, say, German-English or African-English. I bring this up because I came across a passage in the book that was particularly salient within this context. In his description of the complex socio-ethnic conditions of a Manhattan recently conquered by the English, Bailyn (2012: 516) outlines the response of the newly incorporated citizenry:

In the late 1660s and 1670s the new English province of New York was far different from its neighboring New England  It was a world in flux, its people caught up in complex ethnic tensions, its economy growing but shifting in organization  it government newly established and weakly related to the society it ruled. The great majority of New Yorkers in Manhattan (an estimated 76 percent of a significant sample) were Dutch, as were the settlers sin what were now called Albany and Schenectady, and they expected to remain Dutch under the English regime. In fact, their "Dutchness" was becoming more prominent  as a process of what Joyce Goodfriend has called the "crystallization" of ethnic groups set in. The various groups, she explains, now in a more open society became more self-aware and felt the need to define themselves in institutional form and to preserve their distinctive characteristics  So the Dutch, despite the differences among them, began to "coalesce"-to consciously value their distinct common ground  in the language, religion, customs  and values. So too other groups sought their own places in this province of tolerated diversity.

I'm not sure how "tolerated" all that diversity really was, but this "crystallization" really does seem to be a common response among peoples within multi-ethnic communities, and it may may go some way in explaining the desire of Americans to be so self-aware of their ancestry.

References:

Bailyn, B (2012). The barbarous years: The peopling of British North America: the conflict of civilizations 1600-1675. Alfred E. Knopf, New York.

Goodfriend, JD (1992). Before the melting pot: society and culture in colonial New York City, 1664-1730. Princeton University Press, Princeton.

Bead-making in the early Upper Paleolithic

Mary Stiner and her colleagues (2013) recently published a really fun analysis of shell beads from the Paleolithic site of Üçağızlı Cave I in Turkey. The levels at the site date to the early Upper Paleolithic, between about 41,000 and 29,000 radiocarbon years ago (calibrated dates place the occupations between about 45,000 and 35,000 years ago).

Examples of perforated shells from Üçağızlı Cave I. From Stiner et al. (2013: Figure 5). 

After demonstrating (convincingly) that the modified shells are, in fact, artificially punctured beads, Stiner et al. (2013) show that the types of shells brought back to the cave, and the types that were chosen as beads, change over time. They provide four hypotheses to explain the change in shell type frequencies: (1) environmental changes determined what sorts of shelled animals were living near the cave, and thus what was available for bead exploitation; (2) the distance from raw materials (mediated by sea level fluctuation) changed over time, in which case people would accumulate more "junk" when raw materials were close and/or convenient and be very selective (i.e., only take the best stuff) when raw materials were distant and/or inconvenient; (3) the diversity of shell types is a function of the number and heterogeneity of shell collectors and users (that is, the more folks, and the more types of folks, exploiting shells will result in greater shell diversity); (4) cultural "conformism," where norms determine the types of shells used during any one time period.

The first hypothesis was not supported, as habitats don't appear to have changed significantly over time. The second hypothesis found some support in the fact that the diversity of ornament shells increased in those levels with evidence of frequent shellfish consumption. The latter would, theoretically, signal that the coast, and thus the raw materials for beads, were relatively close by and people became less picky about what they brought back to the cave for ornamental use. However, Stiner et al. (2013) question whether the distances to, and the weight of, the shells would have played much of a role in mediating what was, or was not, transported to the cave.

In the end, they feel that group size and composition and conformist behavior best explain the patterning in shell usage at the site. This is based on two observations. First, an inverse relationship exists between the diversity of species brought back to the site and the frequency of shells that were actually perforated for use as beads. That is, during time periods where many different types of shell were collected, only a few of those types appear to have been utilized for bead use. In the earliest levels, on the other hand, people transported only a few types of shells back to the cave, but most of them were subsequently perforated. Second, the size and shape of perforated specimens is relatively consistent regardless of time period. Stiner et al. (2013: 396) therefore conclude that:

Several factors contributed to the variation in the UcI ornament assemblages. Sample size effects were addressed early in the analysis and do not explain the patterns that concern us. The taxonomic diversity of the assemblages as a whole stems first from the natural biotic diversity of the marine environment. However, changes in littoral habitats to not seem to account for the differences between assemblages or changes over time. Many other aspects of the variation developed as the material was filtered by human choices. The narrow range of shapes and shell sizes is clearly attributable to human preferences, as are the bias toward whole specimens and the methods of modifying the shells for suspension. The extent of 'noise' or variance in the ornament assemblages is a product of the relationship between raw material collection activities and ornament manufacture and use. 

The fact that the taxonomic diversity of the UcI shell ornaments increased with time while the percentage of holed specimens decreased demonstrates that variation in the assemblages must be considered according to two distinct technological stages: raw material collection and artifact manufacture. The more playful and less constrained stage of artifact life history is raw material collection. Variation in overall raw material diversity among the assemblages related in part to how convenient access was to the shoreline and/or the overall importance of marine foraging from UcI. Variation in raw material also correlates with increasing occupation intensity and dietary breadth; the least variable assemblages formed during the lightest occupations. Changes in the size and complexity of the social groups that occupied UcI therefore may have played a role in shaping variation in the ornament assemblages. Unfortunately, the predictions for neutral social effects (more people on site or present for longer periods) and high-grading effects (raw material access) are difficult to distinguish in this particular case. What we can be certain about is that more 'junk' found its way into the shell raw material brought to the site at some intervals and that very different criteria took over at the manufacture stage. As the times collected were streamed into more formal uses, their characteristics narrowed, and many of the shells initially collected were rejected before further modification. It is for these reasons that we conclude that post-manufacture characteristics of the ornament assemblages most clearly reflect the influence of shared esthetic and visual norms. 

I actually ran into this article while I was mining the latest publications on modern human origins, which we are currently covering in my Paleolithic Archaeology class. One of the traits that many archaeologists associate with "modern" behavior is the use of personal adornment, since it is extremely likely that these items were used by ancient people as symbols to transmit information about themselves (just as jewelry does today). Stiner and her colleagues do not involve themselves in the modern human origins debate (as they note, the beads are not among the oldest in the world, or even in the Levant), but there analysis got me thinking about the importance of group size and complexity in the production of symbols. There is, in fact, quite a bit of recent work in Paleolithic archaeology that invokes the importance of demographic factors (mainly population size and density), rather than cognitive factors, to explain the appearance (and disappearance) of symbolic objects among pre-Upper Paleolithic cultures. Think about it: if you interacted with other groups only very rarely, or you ran into the same groups over and over again, there is very little incentive, even if you were cognitively able, to create a ton information transmitters (i.e., symbols) of any kind, much less those that would preserve in the archaeological record.

References:

Stiner, MC, Kuhn, SL, Güleç, E (2013). Early Upper Paleolithic shell beads at Üçağızlı Cave I (Turkey): Technology and the socioeconomic context of ornament life-histories. Journal of Human Evolution 64, 380-398.

Problem-based learning and STEM education

I am part of a network at UNCG called RISE (Research and Instruction in STEM Education), which is a collection of faculty and staff interested in promoting science education. From the network's website:

The goal of the RISE Network is to enhance and expand the already strong partnership between researchers, educators, and science, mathematics, and technology educators in the community and at UNCG. This will be accomplished by developing a network of interested partners to better coordinate STEM education and research across campus. This network will enhance UNCG's ability to broaden access to STEM fields by:

Creating a more coordinated web of opportunities for undergraduate and graduate students to engage in inquiry-based STEM experiences

Supporting curriculum development through revising STEM courses in order to offer an inquiry-based collaborative method of instruction designed to foster skills in critical thinking, quantitative reasoning, and communication, with the goal of promoting the STEM literacy of our graduates

Enhancing the extent to which UNCG supports high-quality STEM education in pre-K–12 classrooms by designing research-based projects that generate and disseminate knowledge about STEM content and pedagogy and are responsive to student, teacher, and district needs

Facilitating collaboration between local community and business leaders and UNCG concerning scientific literacy skills, skills needed for the next generation of the (local) workforce, and instructional policies and programs to meet these needs 

Providing support for faculty and staff who seek external funding to support the above efforts

I attended the latest event this past Monday, which was a workshop entitled, "Is it Really Teaching if Learning Doesn't Happen?" The network brought in Dr. Ann Lambros, who is Assistant Dean of Medical Education and Assistant Professor of Social Sciences and Health Policy at the Wake Forest School of Medicine, to talk about problem-based learning strategies. "Problem-based learning," along with other buzzwords (or buzz phrases, perhaps?) like "high-impact learning," has garnered quite a bit of recent attention from education policy makers. Although I had heard the term before, I have to admit that I really didn't have a concrete sense of what problem-based learning (or PBL) was.

Essentially, PBL begins with a problem, and learning is achieved as students gather information and test hypotheses to solve the problem. We were provided with a really nice review article on the approach by John R. Savery (2006: 12-15), who, after mining the literature, identified several key components of PBL:

• Students must have the responsibility for their own learning
• The problem simulations used in problem-based learning must be ill-structured and allow for free inquiry
• Learning should be integrated from a wide range of disciplines or subjects
• Collaboration is essential
• What students learn during their self-directed learning must be applied back to the problem with reanalysis and resolution
• A closing analysis of what has been learned from working with the problem and a discussion of what concepts and principles have been learned are essential
• Self and peer assessment should be carried out at the completion of each problem and at the end of every curricular unit
• The activities carried out in problem-based learning must be those valued in the real world
• Student examinations must measure student progress towards the goals of problem-based learning

In her introduction, Dr. Lambros related why Wake Med made the switch to PBL. Studies had shown that med students were struggling to (1) solve problems, (2) stay engaged, and (3) make connections between various concepts. So, they were looking for a new way of doings things; after all, Dr. Lambros said, and I liked the analogy that was made, memorizing a maze was easy enough to do, but the learning becomes useless if the exit is moved.

The attendees went through a PBL exercise, and it works more-or-less like this: First, a real-world problem is presented that requires both some prior knowledge and the acquisition of new knowledge. The group must lay out the facts that are known, decide what sorts of assumptions can or cannot be made, and relate the problem to existing knowledge. Second, students need to identify what additional information is required and, through self-directed learning and open inquiry, will procure this information and formulate hypotheses. Finally, students are asked to present and defend their hypotheses...and the process starts again with the newly gained knowledge serving as the existing knowledge for the next round.

PBL learning model. From the University of Queensland.

I think any teacher will tell you that one of the biggest obstacles to learning is motivation. While grades are meant to fill this role, students become invested in the grade rather than learning. One of the things I like about the PBL approach is that in the process of exploring a problem and eventually being forced to defend hypotheses based on information they themselves gathered, students are invested in the accuracy of their findings and, in the end, feel a sense of ownership. The other major roadblock to learning is relevance: Students must see that what they are learning is going to be relevant in some concrete way. PBL also addresses this by focusing on real-world problems.

There is, however, one glaring issue here: research has failed to show that PBL actually results in systematically better performance relative to more traditional approaches. The major advantage, it seems, is that students report a preference for PBL. The other problem is that PBL only seems to work well when it is implemented at all levels of a curriculum, and this of course requires that faculty and staff buy in to the approach (something that is MUCH easier said than done). The debate will no doubt go on, but I can see myself designing and implementing PBL lessons to see how it works.

References:

Savery, JR (2006). Overview of problem-based learning: definitions and distinctions. Interdisciplinary Journal of Problem-based Learning 1, 9-20.

Apps for education

I'm part of a Learning Community at UNCG called Technological Tools for Teaching, and the group sponsored an App Fair highlighting apps that others had found useful in an educational setting. So, I thought I'd share some of the more interesting, and potentially most useful, apps:

• If your school is a subscriber, Browzine (pronounced "browsing," in the library sense) is a cool app that allows you to browse, read, and monitor academic journals. New issues are automatically displayed on your bookshelf, and they can be synced up with things like Zotero and Dropbox.
• GoSoapbox is an instant polling app (kind of like the clickers some universities utilize) that students can access and use with their smart devices (they all have them, and use them in class, anyway, so why not for education?!). Use this access code to play around with it: 403-011-389. There is a 30-day free trial, and then a $10/year fee for instructors.
• Feedly is a cool app that allows instructors to organize multimedia materials for teaching and students to designing assignments. It allows aggregation of web pages and other materials that are not easily captured via traditional programs (e.g., word processors, presentation software). Many have found this to be a good replacement for Google Reader.  

Reconstructing subsistence during the Plio-Pleistocene

I just finished going through an interesting analysis by Michael Pante of the large mammal faunal assemblage from the site of JK2, which is in Bed III of Olduvai Gorge and dates to approximately 1.0 million years ago. The study in important for a number of reasons, not the least of which is the fact that we have so few decently preserved faunal assemblages that date to this time period. What is more, JK2 preserves butchery marks, another rarity among sites of this age, which show definitely that hominins (in this case, probably Homo erectus) were cutting flesh from carcasses and breaking open bones for marrow.

Ultimately, Pante uses the frequency and anatomical placement of the butchery marks and the carnivore tooth marks to argue that Homo erectus was gaining early access to carcasses (that is, before other carnivores had a chance to consume the carcass). This is potentially important, because there has been a lot of discussion about the importance of meat in the diets of early hominins. If meat was a staple of the diet, it is possible that it partly drove other evolutionary changes such as increased brain size (meat is easy to digest, so if you could free up energy that is usually channeled to the guts to process food, it can be diverted to other important organs, namely the brain). Pante compares the frequencies of butchery and tooth marks in the fossil assemblage to experimental assemblages of bones exposed to various processes:

• Hammerstone-only, in which humans cut the flesh from bones and then broke them open with stones to access the marrow
• Carnivore-only, in which carnivores (mainly hyenas) consumed carcasses
• Hammerstone-to-carnivore, in which humans cut the flesh from bones, broke them open for the marrow and, afterwards, carnivores scavenged the remains
• Whole bone-to-carnivore, in which humans cut the flesh from the bones but left everything else (flesh scraps and marrow) for carnivores to scavenge
• Vulture-to-hominin-to-carnivore, in which vultures ate some of the flesh, humans broke open the bones for marrow, and then carnivores scavenged the leftovers

The important observation here is that each of these experimental scenarios results in different frequencies and locations of butchery and tooth marks. For example, when humans remove the flesh and the marrow, there are very few tooth marks, since carnivores have little reason to gnaw on bones that are devoid of edible tissue.

While I agree that Homo erectus probably gained early access to carcasses, what struck me is the fact that the JK2 assemblage really does not match up very well with any of the experiments. I have run across this myself in analyses of other assemblages, and I can't help but wonder that the experimental scenarios that we've come up with so far, while extremely useful, simply are not comprehensive enough to model the complexities we're seeing at these Plio-Pleistocene sites, a point that Pante concedes in the paper. Regardless, this paper provides additional data on a critical, and currently poorly sampled, time period.

In my mind, two of the most important things that Plio-Pleistocene taphonomists need to work out are (1) reaching consensus on exactly how we identify marks on bones and (2) producing experimental bone assemblages that can test a wider variety of potential behavioral scenarios.

References:

Pante, MC (2013). The larger mammal fossil assemblage from JK2, Bed III, Olduvai Gorge, Tanzania: implications for the feeding behavior of Homo erectus. Journal of Human Evolution 64, 68-82.