Friday, March 15, 2013

Introducing Archaeology

I haven't taught Intro to Archaeology in five years. Confession time: I don't like the class. It's so hard to make it interesting and relevant, even for someone (like me) who loves archaeology!

In Intro to Biological Anthropology, I tackle fundamental questions of what makes us human and what is determined by our biology, and take down myths of race and gender. In Intro to Cultural Anthropology, too, I can challenge students' perceptions of the world, exposing them to a whole range of ideas and behaviors that contextualize their daily lives. It's interesting. It's exciting. It's big-picture.

But I've never seen an Intro to Archaeology class taught that way. The focus is either on methods (relevant only to majors), or on cramming in lots of facts about individual cultures (this gets boring, even to me). It's illustrative to look how Intro to Archaeology textbooks are structured, in contrast to Intro to Cultural Anthropology or Biological Anthropology. While Cultural and Biological textbooks tend to have chapters focused on big themes or questions (race! religion! human adaptation!) the Archaeology textbooks are organized along geographic and temporal lines (Pleistocene hunter-gatherers. Neolithic farmers of southwest Asia. The Empire of...zzzz.)

I'm not sure I agree with "Archaeology is Anthropology, or it's nothing", but Archaeology is a hell of a lot more interesting if it's anthropological. Archaeologists can speak to big-picture questions, so why the hell don't we in introductory classes? Where is the archaeological textbook with thematic chapters dealing with the important questions that Archaeology is best equipped to answer, those questions whose answers require long-term observation of human populations all over the globe?: Why does inequality develop? How do we define sustainability, and how have people attained (or failed to attain) it in the past? What causes culture change? And why can't we explore these questions with examples from all over the time-space continuum?

I think we fear to introduce the examples we need to explore these questions without first introducing students to the cultures in question (which requires the geographic-temporal approach). Yet, Intro to Cultural Anthropology textbooks do it all time, spending only a paragraph on a culture, and explaining how it illustrates the point, without getting bogged down in the details of how many post-holes are found in the village's community house.

The closest thing I've seen to a thematically-organized Intro to Archaeology textbook is the old Out of the Past book, with its coordinating movies. That was published in 1992. Can someone please tell me that there's another diamond out there that I just haven't discovered?

Update: I did find this book, What Happened in Prehistory? by Peter Peregrine. It's a short e-book, and only $2.99. It's not really a textbook, but it's a nice overview written for a popular audience, and at least looks at the big picture. I wonder if I could use it, supplemented with other materials.

Monday, March 11, 2013

Look what the economists do with human diversity data

A colleague in Economics sent me this article:

Ashraf, Quamrul and Oded Galor. 2013. The 'Out of Africa' Hypothesis, Human Genetic Diversity, and Comparative Economic Development. American Economic Review 103:1-46.

Here's the abstract. It gives the jist of the article, if you can't get access:

This research advances and empirically establishes the hypothesis that, in the course of the prehistoric exodus of Homo sapiens out of Africa, variation in migratory distance to various settlements across the globe affected genetic diversity and has had a persistent hump-shaped effect on comparative economic development, reflecting the trade-off between the beneficial and the detrimental effects of diversity on productivity. While the low diversity of Native American populations and the high diversity of African populations have been detrimental for the development of these regions, the intermediate levels of diversity associated with European and Asian populations have been conducive for development. 
Anthropologists recognize this argument: yet another a pseudo-evolutionary craptasmagoria that purports to explain why European and Euro-American populations are inherently superior to African and Native American populations, thereby justifying global inequalities in economic/political power and negating any guilt that dominant societies may have about the legacy of colonialism and genocide. These arguments are always flawed, but it doesn't stop them from cropping up again and again. Or, to quote my new-favorite Jonathan Marks blog post"We have been here before; douchebags are always recruiting Darwin to their stupid views about human society."

The fundamental flaw in the argument is that there is no reasonable mechanism by which diversity affects productivity. Ashraf and Galor claim that some diversity is necessary for economic innovation, because a population's ability to create culturally innovative ideas is tied to its genetic diversity. I would argue our genetically-created ability for flexible behavior, which is shared by all humans, allows for innovation, but in this paper, fewer different alleles = fewer different ideas. Or something. 

Their argument against "too much" diversity is that highly genetically diverse populations are economically inefficient because people who are physically different aren't as willing to cooperate with each other.  (Kin selection was invoked in this context, including the foraging efficiency of groups of closely related spiders vs. spiders who are not related. It made my head hurt.) Of course, anthropologists understand that that physical variation is culturally categorized, as is our understanding of kinship, so genetic diversity and biological relatedness may have nothing to do with how different or similar you consider others in your community.

But even if you accept the mechanisms proposed by the authors, or consider them worth testing, the anthropological data that Ashraf and Galor use to show a hump-shaped relationship between genetic diversity and economic productivity do no such thing. The analysis is extremely problematic, both in the way it measures diversity and in the way it measures economic productivity.

The paper has two arguments, one related to modern economic productivity, and the other related to pre-industrial productivity. I'm only going to discuss the pre-industrial argument here because it's the topic I'm best qualified to tackle. The argument goes like this: prior to the industrial revolution, economic productivity is best measured by population density. These pre-modern economies were agriculturally-based, and surplus tended to be put into population growth. (The authors call this the "Malthusian epoch", a phrase I'm totally stealing.) Of course, in reality, surplus is put into many things, like building pyramids, or irrigation systems, or waging war. But I won't quibble on that point.

Ashraf and Galor set out to prove that the relationship between population density and genetic diversity is hump-shaped, suggesting that moderate amounts of diversity are ideal for population density (their proxy for economic development). This is shown in Figure 3 (p. 22), reproduced below. But before we accept this relationship, we have to ask two questions: Does this graph accurately reflect the diversity of the continents in 1500CE? And, does this graph accurately reflect the economic development of those continents?

Does this graph accurately show the diversity of Europeans, Africans, Asians, and Americans in 1500CE? 

Yes, and no. Ashref and Galor label the dots in Figure 3 with names of modern states. But the genetic data they are using is not generally representative of the people who lived within those borders. The data on genetic homogeneity (a measure of diversity) comes from the HGDP-CEPH Human Genome Diversity Cell Line Panel, as published by Ramachandran et al. (2005). Ramachandran et al., to simplify, showed that genetic diversity is highest in Africa and gets lower the farther you go from the origins of our species. This is clearly true. But Ramachandran and colleagues focused on genetic diversity in isolated communities, because they were interested in the earliest people to enter these regions. But precisely because these samples were picked from isolated communities, they don't say much about diversity in those nations overall at 1500 CE. 

For example, the UK is represented in this sample by one ethnic group: Orcadian Islanders. Now, the Orkney Islands are not without their history of migration and admixture - they've been passed between Scotland and Norway a few times - but this one small population at the upper ends of nowhere can hardly be considered representative of the genetic diversity of the United Kingdom as a whole in 1500 CE, with its history of Roman, Anglo-Saxon, Viking, and Norman influx. Similarly, the nation of Zaire, which today has some 250 ethnic groups, is represented in this data by a single community of Mbuti Pygmies. Most problematic, the entirety of the Americas is represented by only four data points, and the far-right anchor comes from the Karitiana people of Brazil, an indigenous group with only 350 members!

By 1500 CE, there had been a number of major migrations that spread genes across the most populous (that is, least isolated) areas of the world. An estimated 8% of men in Asia carry a Y chromosome believed to come from Ghengis Khan (Zerjal et al. 2003). Cosmopolitan cities existed on all four continents, and the genetic diversity in those cities would have been higher than that in the isolated societies sampled for Ramachandran et al.'s analysis. The city of Teotihuacan in central Mexico, for example, had one neighborhood consisting of Oaxacan merchants. The Crusades led to frequent trade between Europe, North Africa, and western Asia.

By using the genetic diversity of isolated populations to represent the genetic diversity of large states, Ashref and Galor are failing to consider the genetic diversity of the people who were most involved in highly-developed economic systems.

Does this graph accurately show the economic development of Africa, Asia, Europe, and the Americas in 1500CE?

This answer is easier: no. 

First, as mentioned above, the genetic samples tell us about the diversity of small isolated populations, not the diversity of those states as a whole at 1500 CE (or of the people within the modern borders of those states). But the population density estimates (which come from McEvedy and Jones, 1978) are for the states as a whole. To test Ashref and Galor's hypothesis, the genetic diversity of the population should be compared to the estimated population density of those communities (Orcadian genetic diversity compared to the population density of the Orkney Islands, for example). This would be difficult, but not impossible, with archaeological data. It would also utterly destroy the pattern in Figure 3, since the genetic samples from all four continents include some societies that were highly mobile with low population densities (the San, the Bedouin, etc.) and others that were highly sedentary and lived in cities (Japanese, Mayan etc.). 

Second, the population density estimates are problematic. I haven't gotten a copy of McEvedy and Jones (1978) yet, but looking at the data used by Ashref and Galor, the population estimates for the Americas, at a minimum, are too low. There is a long history of underestimating the indigenous population of the Americas, partly because early European records justified colonization efforts on the basis of "empty" land for the taking, and partly because accurate estimates of population at Contact would show such high death rates for the indigenous population that many Euro-descended researchers have shied away from suggesting or accepting them. The data from Brazil is pulling the curve in Figure 3 downward on the right side, a major determinant of its shape. Since McEvedy and Jones's publication in 1978, our understanding of pre-Contact Brazilian history has changed radically. We now know the population density of the Amazon region was far higher than previously thought (for example, Heckenberger et al. 2003). Moving the American data points upward would radically change the shape of the curve. I can't speak to the African population density data, but any errors in the estimates for South Africa (another area where European colonists denied the existence of previous occupants) would also flatten the curve.

A major problem with using population densities as a proxy for economic development, is that by using the population densities within modern national borders, Ashref and Galor are significantly underestimating pre-modern population density in highly-developed areas by lumping them with low-productivity areas. This is less of a problem in Europe, where modern nations tend to be smaller (although it explains Russia's very low density relative to other European nations, or China's relative to Japan), but is more problematic in the New World. Mexico, for example, includes not just the highly populous regions of the Valley of Mexico, but also the low-density regions of the Sonoran and Chihuahuan Deserts, and the Sierra Madres. A more reasonable comparison would be the population density of the UK vs. that of the Aztec Empire, or of the Mali Empire.

Why do we care?

Ashref and Galor argue that biological traits of populations determine (or at least affect) their level of economic prosperity. In doing so, they add their work to the long history of attempts to prove inherent racial differences lead to inequality, rather than inequality being the result of systemic attempts to deny opportunity to others. And they did so in one of the most prestigious journals in their field.

I've never met Ashref or Galor, and I know nothing about them. I have no idea if they harbor personal biases toward any group of people. They may both be saints, dedicating their life to social justice and the pursuit of equality. It doesn't matter. Given the salience of race in Western society, any argument for biological determinism must be held to a high standard of evidence, and the authors must accept responsibility for the political and social implications of their work. They cannot pretend it doesn't matter, or that they're not making an inherently political argument. 

 They walked into a crowded theater and yelled "Fire!" They are responsible for the consequences, whether they did so with malicious intent or not. To yell "Fire!" on the basis of  a manufactured hint of smoke is irresponsible at best, at worst, it is criminal.

I'll leave you with a final quote, this one from Charles Darwin, whose intellectual legacy was so poorly used by Ashref and Galor: “If the misery of the poor be caused not by the laws of nature, but by our institutions, great is our sin.” 

Admitting sin is hard, but blaming the victim is unconscionable


Heckenberger, Michael J., Afukaka Kulkuro, Urissapa Tabata Kulkuro, J. Christian Russell, Morgan Schmidt, Carlos Fausto, Bruna Franchetto. 2003. Amazonia 1492: Pristine Forest of Cultural Parkland? Science 301: 1710-1713.

McEvedy, Colin, and Richard Jones. 1978. Atlas of World Population History. New York: Penguin Books.

Ramachandran, Sohini, Omkar Deshpande, Charles C. Roseman, Noah A. Rosenberg, Marcus W. Feldman, and L. Lucas Cavalli-Sforza. 
2005. Support from the Relationship of Genetic and Geographic Distance in Human Populations for a Serial Founder Effect Originating in Africa. PNAS 102 (44): 15942-15947.

Zerjal, Tatiana et al. 
2003. The Genetic Legacy of the Mongols. American Journal of Human Genetics 72:717-721.

Update: Turns out the anthropologists at Harvard are on this! Check out this open-access article in Current Anthropology reviewing the article.

Guedes, Jade d’Alpoim and others. 
2013  Is Poverty in Our Genes? A Critique of Ashraf and Galor, “The ‘Out of Africa’ Hypothesis, Human Genetic Diversity, and Comparative Economic Development,” American Economic Review (Forthcoming). Current Anthropology 54: 

Saturday, March 2, 2013

Diet is More than Food: It's Also a Study in Privilege and Gender

This isn't the usual beat for this blog, but I ran across this blog post on eating healthy using the Whole9 approach by The Minimalist Mom. I used to be a devoted reader of "Mommy Blogs"*, but I stopped reading them because they made me feel so needlessly inadequate. (Seriously, if you're an academic mother, one of the first steps toward work/life balance is to stop reading those damn blogs.) I really enjoy(ed) The Minimalist Mom, and I wholeheartedly agree with her approach to minimizing her consumption, debt, and time sinks. I also have a lot of respect for Whole9 and their approach to healthy eating. I don't agree with everything they recommend, but I'm not unsympathetic to their cause.

Nonetheless, The Minimalist Mom's post on her family's Whole9 diet had me fuming.

There's a reoccurring problem with both the minimalist movement and whole foods movement (and this includes a whole bunch of popular blogs and books, from Radical Homemakers to The Omnivore's Dilemma): they consistently ignore issues of gender and privilege. This most recent blog post is not the worst of the offenders, but it caught my attention, so cue the rant:


All it takes, we are told, to live a "good" life, is a little time and effort on our part. And just a little sacrifice. Eating healthy doesn't require you to be rich, it just means giving up some unnecessary extravagances. The Minimalist Mom mentioned several items that could be easily given up or changed in order to afford higher-quality food:

iPhone - An estimated 55% of Americans own a Smartphone. That leaves 45% of the country who can't afford one. Personally, I have a cheap pre-paid cell phone.

cable plan - Most Americans have cable. They probably could give it up. I don't own a television.

drive a second-hand car instead of a new one - I've never bought a new car in my life. I can't remember anyone in my family ever buying a new car. We are not the only ones who usually buy used. We currently drive a 10-year old minivan that we bought with 100,000 miles on it. We consider it new. 

sell your car - Our nation is built for cars. Many people can't get to work or the grocery store without one. To find housing that is both affordable and safe, many people have to live far from their place of employment. I am lucky enough to live in a very small town where I can walk almost everywhere, but even I need a car, unless I want to carry an infant on the 25-min walk to daycare through -35 windchills.

vacation closer to home - Vacation? Since when has a vacation been anything but a privilege? I'm very lucky to be able to visit family in different parts of the country, and to get money from work to attend conferences or do research all over the world. Most people don't take "vacations" in the sense of a yearly trip away from their home to Vail or Cancun.

get a job closer to home - We currently have 8% unemployment. That number is far higher for individuals without a college degree and for people of color. It's not that easy to find a job, and, as discussed above, it's not that easy to move close to your place of employment.

So, other than giving up cable, most of the items on The Minimalist Mom's list are items of privilege. In other words, only well-off people can afford this diet. And even if a person can afford it, it's not necessarily easy to follow. For example, I live in a rural area. Although we have a farmer's market, a food co-op, and some local organic farms, access to affordable organic food is difficult. It requires driving around the countryside to collect the food, access to storage (like a large freezer), and paying even higher prices than in cities, since shipping costs are high. And some organic fruits and vegetables are just not available, period.

I'm a very privileged person. I have a great job. I've never gone hungry. I've never faced racial discrimination. I have access to affordable health care through a wonderful insurance plan. I can afford high-quality daycare with excellent teachers. We can even afford to send our daughter to our parish school (luckily, much cheaper than private schools in cities). But even I'm not privileged enough to follow this diet. How can a family living in poverty, or a family who is one paycheck away from poverty, possibly manage? Yet, the message behind The Minimalist Mom's blog post (and many, many similar books and blogs) is that we are selfish for not providing our family with adequate nutrition, and it would be so simple for us to do so!


It takes more time to buy, process, and serve healthy foods. Who does most of this work? Mom, of course! Men are more likely to do housework and childcare now than in the past, but women in the U.S. still are overwhelmingly responsible for cooking, cleaning, and caring for the kids. And, of course, 35% of children live in single-parent homes, mostly headed by women. If we want to follow Michael Pollan's advice "don't eat anything your great-great-grandmother wouldn’t recognize as food", does that include a return to gender roles our great-great-grandmothers would recognize, as well? 

Not necessarily, of course. The "green" movement, the "whole foods" movement, the "minimizing" movement could focus on the importance of equal responsibilities within the family. But, by and large, they don't. Just as the issue of privilege tends to be ignored or minimized ("gee, it only takes a little sacrifice"), the gender problem tends to be ignored or minimized ("one partner can stay home", as if that "one partner" wasn't the woman in a heterosexual relationship, 95% of the time). 

Don't get me wrong. If I had more hours in the day, more energy, more money, I would put them into better health for my family. But, at the moment, I can barely keep the dirty clothes from building up on the floor, the dishes from piling up in the sink, or my job (and my husband's job is dependent on mine, so I can't just stay home). In other words, if there's a hierarchy of needs for the family, then I'm well above "basic subsistence", but not yet to "home-canning tomatoes", even though I'd like to be. And I'm not alone. Our food industry, food distribution system, employment and gender structures make it very difficult for poor families and two-income families to provide healthy food for their children. By ignoring issues of privilege and gender, we're suggesting cures that put more pressure on individuals ("can't you just make those little necessary sacrifices?") rather than dealing with the underlying structural problems. We're creating a situation where only the privileged are given access to health, and where traditional gender roles are imposed in order to provide it. Maybe that's what we want as a society, but that should be the discussion, not whether or not it's worthwhile to "give up" an iPhone in order to eat well.

*Am I the only person who dislikes this term because it seems dismissive and condescending?