Archive | November, 2012

It’s About Animal Bones!

28 Nov

Einstein was right.

In addition to his staggering theoretical contributions, Einstein believed in the possibility of making science more accessible.  He challenged: “If you can’t explain it more simply, you don’t understand it well enough.”

 

Image source: img.ly/iamc

 

Einstein’s quote popped into my head recently when an article I co-authored was published online in the Journal of Archaeological Method and Theory (JAMT).  Despite my fervent belief in popularizing anthropology, I found myself preemptively warning friends and family that “it’s really dense and technical, so don’t feel obligated to read it.”  And, it’s true, “The Taphonomy of Resource Intensification: Zooarchaeological Implications of Resource Scarcity among Bofi and Aka Forest Foragers” is not leisurely beach reading.  It’s written for a narrow audience of specialists who are familiar with such jargon and the ideas behind it.

Researchers are often notoriously bad at explaining their own work in plain English.  I’m still frozen by what should be the simplest question: “What is your article about?”  Obviously, I know the material inside out and backwards, and that’s part of the problem “experts” in every field face; we know our subjects so well and have been working with them for so long that we forget how to translate them into everyday language!  If we take Einstein’s quote to heart, then a true master of anthropology (or any particular area of expertise) should be able to simply explain their research to a wider audience of non-specialists.

 

In that spirit, our article is about animal bones.  (See, I almost wrote “faunal remains” out of habit, but “animal bones” is simpler and works just as well, doesn’t it?)  We worked with modern day Bofi and Aka hunter-gatherers (so-called “pygmies”) in Central Africa to better understand how prehistoric hunter-gatherers might have hunted, shared meat, and butchered animal carcasses.  This type of research is called ethnoarchaeology, the study of animal bones from archaeological sites is called zooarchaeology, and exploring the processes that affect these animal bones is taphonomy.

For my Ph.D. dissertation, I analyzed the food bones that Bofi and Aka families threw away after their evening meals (years in a laboratory looking at garbage…).  In this JAMT paper, we compared bones from two Central African villages; one where animal prey were relatively abundant (Ndele), and another where they were more scarce (Grima).

We based our analysis on some theoretical models of foraging behavior.  These models predict how we expect a hypothetical optimal forager to behave in different situations.  One basic prediction is that foragers in “depressed” environments, where highly-prized (usually larger) animals are rare, will expand their diet to include a range of smaller animals.  For example, if deer are rare, you might focus on rabbits and birds – but it takes a lot of rabbits and birds to equal the meat weight of just one deer.  Another prediction is that foragers in depressed environments will butcher the animals they’re lucky enough to kill more intensively.  Using the previous example, if deer meat is a rare treat, you’re more likely to cut every last morsel of meat from the bone, letting nothing go to waste.

These theoretical predictions often match what we see in the real world pretty well – and, if we do things right, we can use them to explain the behavior of ancient humans.  So we applied foraging theory to our two Central African villages.  When comparing the Ndele and Grima bone collections, we expected Grima – where bigger animals were scarce – to feature 1) bones from more, and smaller, animal species and 2) bones that were more intensively butchered, as measured by cut marks and fracturing.  Pretty simple things to test, right?

 

Results of Test 1: Sure enough, the Ndele bone collections were dominated by the largest locally-available prey, duikers.  The Grima collections included much greater proportions of smaller species like porcupines, rats, and mice – a broader diet to compensate for the relative scarcity of duikers.

Results of Test 2: Just when everything seemed to be matching foraging theory predictions so perfectly…  Most measures we used showed that Grima bones were not more cut (from intensive butchery) or more fractured (from intensive marrow processing).  We discuss several reasons why this might be the case.  A major reason is that processing intensity has mostly been investigated on the bones of large mammals, like caribou and moose.  Most animals hunted by forest foragers weigh less than 25 kilograms (about 55 lbs.).  Large mammals must be intensively filleted, cutting meat from bone.  The blue duikers, so highly prized by forest foragers, are quickly chopped up with machetes and boiled in pots – no fillet marks necessary.  This technique also releases marrow, in the form of soup broth, without intensive fracturing of bones.

These results remind us that foraging models are simple guides; they generate hypotheses that we can then test against actual human behavior.  In this case, theoretical expectations based on large Arctic mammals don’t work very well when applied to the smaller rain forest species hunted by the Bofi and Aka.  We are challenged to better understand these processes before using them to interpret behavior from archaeological animal bones.  And an optimistic conclusion: “…additional taphonomic data on prey processing from ethnoarchaeological contexts will doubtless afford some fruitful insights.”

 

That’s “The Taphonomy of Resource Intensification” in a very small nutshell (condensed from a 23-page article).  It’s about animal bones!  Hopefully, I explained it clearly and simply enough that Einstein would approve.  Of course, the stuff he was working with makes zooarchaeology look very, very simple in comparison.

 

Understanding Evolution

16 Nov

Last year I wrote a post for anthropology.net called “I Believe in Evolution.”  The title was meant to be an attention-getter, but most readers understand that evolution is not a “belief” in the same sense as political or cultural beliefs.

Scientific theories are evidence-based and must be overwhelmingly supported by the evidence to be generally accepted in the scientific community.  Evolution is one of the most well-supported theories in all of science, withstanding over 150 years of intensive inquiry in fields from Anthropology to Zoology, Geology to Genetics.  No serious or informed person doubts that Homo sapiens evolved from earlier, more “ape-like” hominins.  In contrast, beliefs can be based on absolutely anything (with or without evidence), or nothing at all.  (Whether belief in empirical evidence is itself “just another belief” is an endless philosophical argument that I don’t want to get into here).

So, despite the title that I chose for that post, evolution is more a matter of understanding the evidence for it than believing in it.  Jerry Coyne, author of the highly recommended book Why Evolution Is True, posted a picture (from The Skeptical Avenger) on his website yesterday that makes the distinction between belief and evidence-based understanding very nicely – along with an array of hominin skulls to illustrate the point.

“Humans” @ Science News

13 Nov

What is anthropology?  The American Anthropological Association describes it as:

“…the study of humans, past and present. To understand the full sweep and complexity of cultures across all of human history, anthropology draws and builds upon knowledge from the social and biological sciences as well as the humanities and physical sciences. A central concern of anthropologists is the application of knowledge to the solution of human problems. Historically, anthropologists in the United States have been trained in one of four areas: sociocultural anthropology, biological/physical anthropology, archaeology, and linguistics. Anthropologists often integrate the perspectives of several of these areas into their research, teaching, and professional lives.”

Like all definitions of anthropology, this one makes reference to humans – like most, it makes explicit reference to science.  Whenever I need a brief phrase to describe anthropology (e.g., to clarify that anthro isn’t about bugs or dinosaurs), I call it “the science of all aspects of humanity: biology, culture, language.”  That works, and it points to my broader interest in science as a whole (including bugs and dinosaurs!).

As an all-around science geek, I love to read widely about scientific research, often at the boundaries of anthropology – and beyond! (as Buzz Lightyear says).  Science News is a great magazine for people with broad scientific interests, a group that probably includes YOU, since you’re reading this.  It’s published by the nonprofit Society for Science & the Public, and recognizes that even smart, scientifically-literate people can’t be experts in everything.  They print brief articles on a wide array of topics geared toward interested non-specialists.  For example, I have no background in physics or chemistry, but can comprehend and enjoy Science News articles about these topics.  I highly recommend checking out their online articles, especially the “Humans” section, which includes anthropology, archaeology, behavior, and psychology subheadings.  Happy reading!