Archive for December 23, 2014

WGF in the News: Grantee Habiba Chirchir Leads Important Study

Habiba Chirchir is a biological anthropologist and currently postdoctoral researcher at the Smithsonian Institution’s National Museum of Natural History. A native of Kenya, Dr. Chirchir received the Wadsworth Fellowship which enabled her to complete her graduate education at New York University and George Washington University’s Center for the Advanced Study of Hominid Paleobiology. A specialist in human bone density and skeletal anatomy, Chirchir is the lead researcher in this newly-published study tracing shifts in bone density in human populations and their relation to parallel changes in lifeways.

Lightweight Skeletons of Modern Humans Have Recent Origin

Decrease of “Spongy” Bone Related to Adoption of Sedentary Lifestyle

New research shows that modern human skeletons evolved into their lightly built form only relatively recently—after the start of the Holocene about 12,000 years ago and even more recently in some human populations. The work, based on high-resolution imaging of bone joints from modern humans and chimpanzees as well as from fossils of extinct human species shows that for millions of years extinct humans had high bone density until a dramatic decrease in recent modern humans. Published this week in the Proceedings of the National Academy of Sciences, the findings reveal a higher decrease in the density of lower limbs than in that of the upper limbs, suggesting that the transformation may be linked to humans’ shift from a foraging lifestyle to a more sedentary agricultural one.

“Despite centuries of research on the human skeleton, this is the first study to show that human skeletons have substantially lower density in joints throughout the skeleton, even in ancient farmers who actively worked the land,” said Brian Richmond, an author of the study and curator in the American Museum of Natural History’s Division of Anthropology.

Modern people (right) have unusually low density in bones throughout the skeleton, including the hand bone joints (metacarpal heads) shown here. This study shows that bone joint density remained high throughout human evolution spanning millions of years, until it decreased significantly in recent modern humans, probably as a result of an increasingly sedentary lifestyle. From left to right: modern chimpanzee, Australopithecus, Neanderthal, and modern human. (© AMNH/J. Steffey, courtesy of Brian Richmond)

Compared to our closest living relatives—chimpanzees—as well as to our extinct human ancestors, humans are unique in having an enlarged body size and lower-limb joint surfaces in combination with a relatively lightweight skeleton. But until now, scientists did not know that human bone joints are significantly less dense compared with those of other animals, or when during human evolution this unique characteristic first appeared.

“Our study shows that modern humans have less bone density than seen in related species, and it doesn’t matter if we look at bones from people who lived in an industrial society or agriculturalist populations that had a more active life. They both have much less bone density,” said Habiba Chirchir, lead author of the paper and a postdoctoral researcher at the Smithsonian Institution’s National Museum of Natural History. “What we want to know now is whether this is an early human characteristic that defines our species.”

To explore this question, Chirchir, Richmond, and an international team of researchers used high-resolution computed tomography and microtomography to measure trabecular, or spongy, bone of the limb joints in modern humans and chimpanzees, as well as in fossil hominins attributed to Australopithecus africanus, Paranthropus robustus, Homo neanderthalensis, and early Homo sapiens. Their results show that only recent modern humans have low trabecular density throughout limb joints, and that the decrease is especially pronounced in the lower joints—those in the hip, knee, and ankle—rather than the upper joints in the shoulder, elbow, and hand. The appearance of this anatomical change late in our evolutionary history may have been a result of the transition from a nomadic to a more settled lifestyle.

“Much to our surprise, throughout our deep past, we see that our human ancestors and relatives, who lived in natural settings, had very dense bone. And even early members of our species, going back 20,000 years or so, had bone that was about as dense as seen in other modern species,” Richmond said. “But this density drastically drops off in more recent times, when we started to use agricultural tools to grow food and settle in one place.”

This research provides an anthropological context to modern bone conditions like osteoporosis, a bone-weakening disorder that may be more prevalent in contemporary populations due partly to low levels of walking activity.

“Over the vast majority of human prehistory, our ancestors engaged in far more activity over longer distances than we do today,” Richmond. “We cannot fully understand human health today without knowing how our bodies evolved to work in the past, so it is important to understand how our skeletons evolved within the context of those high levels of activity.”

In future studies, the researchers will explore the ways in which the bones are less dense than those of our evolutionary relatives.

This work was supported by the Wenner-Gren Foundation Wadsworth Fellowship, The Leakey Foundation Baldwin Fellowship, Smithsonian’s Peter Buck Postdoctoral Fellowship, and the National Science Foundation grant #s BCS-0521835 and DGE-0801634.

WGF Symposium #150: “Integrating Anthropology: Niche Construction, Cultural Institutions, and History”

Front: Leslie Aiello, Cristina Moya, Doug Bird, Ashley Grimes, Kathryn Coe, Mary Shenk, Maurice Bloch, Polly Wiessner, Beverly Strassmann, Laurie Obbink. - Back: Agustín Fuentes, Greg Downey, Pierre Lienard, Ben Purzycki, Alan Barnard, Lee Gettler, Barry Hewlett, Scott Atran

Wenner-Gren Symposium #150, “Integrating Anthropology:  Niche Construction, Cultural Institutions, and History” was held this past October 17-23 in Sintra, Portugal. Like all of our symposia, the work presented here will be featured in a future special open-access issue of Current Anthropology!

All anthropologists, no matter their subdiscipline or field, are interested in why humans do what they do.  In past decades, anthropologists, and particularly those in North America, worked across disciplines drawing on many applications of evolutionary, economic, and cultural theory.

In the 1980s and 1990s a broad diversity of new theoretical approaches emerged.  More humanistically oriented anthropologists, rejecting metanarratives, focused on how humans create complex cultural meanings and realities. Scientifically oriented anthropologists focused on evolutionary and biological influences. Hostilities grew and even in North America, where the Boasian tradition of broad-based anthropology was the norm, some departments split and the discipline divided.

These divisions are devastating to anthropology’s ability to confront the many critical problems in the world today.  There are pressing issues that demand generous engagement between ethnography, social theory, evolutionary theory, biology and socioecology.  These include globalization, environmental degradation, growing inequalities, the impacts of new technologies, and social strife.

The many methodologies and theoretical investments of our diverse practitioners have led to rich understandings of human beings and being human, but at different explanatory scales. To integrate these perspectives we need a starting point. The goal of this conference, and the special symposium issue of Current Anthropology to follow, is to assemble researchers working across sub-fields and theoretical orientations and invite them to collaborate on developing ideas for integrating anthropology that run deeper than many current “biocultural approaches,” and realize these ideas via concrete case studies and innovative methodologies.

The framework we are seeking to build will include evolutionary influences, ethnographic realities, ecological niches, technologies, and cultural institutions. We need to explain gene-culture interactions as well as the sources of enormous cultural diversity in human societies. Research strategies to address the big questions require theoretical plurality and diverse methodologies. This mode of integrating approaches in anthropology will have much to offer the discipline, the academy, and society.

 

Engaged Anthropology Grant: Matthew Walls

A screenshot from Adobe Premiere of a young kayaker learning to throw a harpoon.

Matthew Walls is SSHRC Postdoctoral Fellow in Arctic Archaeology at the University of Oxford’s Institute of Archaeology, and a recipient of the Engaged Anthropology Grant. In 2011, while a doctoral student at the University of Toronto, he received a Dissertation Fieldwork Grant to aid research on “Frozen Landscapes, Fluid Technologies: Inuit Kayak Hunting and the Perception of the Environment in Greenland,” supervised by Dr. Max Friesen.

“To me, it makes sense, and the meaning is there” one participant tells me, after reviewing a sequence of footage we have been working on (above). The scene we were watching is from 2010, and it shows him teaching harpoon throwing. This was is a typical moment in my engagement project, this summer, and we were in the final stage of editing a documentary film on Inuit kayaking. Using video clips from my doctoral project, the idea is to adapt my research and co-produce something of value to the community. It has been in production since 2011, and the Engaged Anthropology Grant allowed me to return to the towns of Ilulissat and Sisimiut in order to ensure that participants can hear their own voices in the final cut by opening the editing process to them.

The community I worked with, from 2009-2011, build kayaks and practice traditional skills as a way of exploring Inuit heritage. Specifically, they find meaning in the persistence of kayaking because the physicality of the skill involves forms of cultural and environmental knowledge that can exist only through practice. As an archaeologist, I was interested in the theoretical implications this idea has for understanding the relationship between people and materials through time. I conducted three seasons of ethnoarchaeological fieldwork which documented the process through which Inuit become skilled kayakers. In my dissertation, I argued that understanding how sensorimotor knowledge is constructed between generations allows for archaeological narratives that better emphasize the agency of skilled practice through time.

Co-editing the arrangement of a sequence.

As a partnership project, it was important for the community to have a voice in interpretation, and to produce materials they find meaningful and accessible. The film was one of several initiatives[i] to accomplish this, and the idea was originally proposed by an Elder as a way of creating something that would be valuable to future generations. Visual media was a prominent part of the research methodology, and this resulted in many hours of footage from interviews, community events, kayak construction, and training which could be used with informed consent. However, as I discovered, editing a film is a matter of weaving image and sound to create a narrative that smoothly conveys an intelligible message to the viewer. A challenge in assembling the film from excerpts was to ensure this process of selection and arrangement did not change the context of what participants had said or demonstrated. To navigate this, the film has been in a process of community review – as sections of the film were edited and sequenced, I showed them to participants via online streaming, which gave them the opportunity to comment and make suggestions for how it should be adjusted. This was a very slow but tremendously useful process, and over distance, it was possible to create a rough cut of the film.

So the Engaged Anthropology Grant gave me the opportunity to complete this process of co-production in person. Returning to Greenland this summer allowed me to show participants an assembled rough cut, to open the editing process to them by demonstrating how the software works, and to make changes together. This resulted in a number of significant developments in the film, ranging from small matters of arrangement to selecting new scenes of kayaking practices to match narration. In one case, a participant opted to re-record an interview to better capture his meaning. Language is a very important feature of the film – it will be in Kalaallisut (Greenlandic) with English subtitles – and during the visit, I reviewed the translations with participants who speak English, who helped me to refine them.

Opening the editing process to the community was also a chance to help develop their capacity to produce their own films. Through participating in the project, several community members became interested in the process of filmmaking and the possibilities it offers them for exploring and preserving kayaking heritage. For example, two participants are now making a film that documents different construction techniques, and another wants to make his own instructional videos about emergency rolls. During the visit, I spent some time helping them to get started with learning Lightworks – an open source video editing program. Returning to Greenland was also an opportunity to archive project materials in local museums, renew personal ties, and discuss possibilities for future research projects.

There are now some small edits and formatting necessary to complete the film[ii]; when it is finished, the community will be able to stream it in Kalaallisut online, and copies will be given to the kayak clubs and local museums.  I think that the finished film will achieve the goal of co-producing something with the community that will have value for future generations in Greenland. In reflecting on the project, it is interesting to see how important the film became as a way of doing the research. The collaboration and refinement it entailed was an important part of co-constructing an understanding of the knowledge involved in the skill. It was my first experience in creating a film, and I’m very excited to include it as a feature of future collaborations.



[i] Other initiatives included a new media project website in Kalaallisut and English (www.qajaq.utoronto.ca).

[ii] Sample scenes from the film can be viewed on the project website: http://www.qajaq.utoronto.ca/english_site/film_trailer/film_trailer.html