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Sunday, May 09, 2010

Neanderthal Science

Are you part Neanderthal? The answer isn't as clear as you may have been led to believe, and this illustrates a problem I see in economics as well. There is often a large difference in the way academic results are reported in the news and what the underlying academic research actually says (this happens frequently, especially with working papers that have not yet been through the refereeing process). The academic work is often much more qualified and tentative than the way it is presented in the media. The problem is that even when subsequent research calls into question or overturns the original work, many of these "facts" live on:

All in the (human) family?, by Rosemary Joyce: Big news in anthropology this past week:... we are all 1% to 4% Neanderthal– or rather, humans of non-African ancestry are. Or maybe not.
As Serge Bloch of the New York Times framed the story, there are “cavemen among us” because “the species most likely had a dalliance or two in the Middle East 60,000 to 100,000 years ago”.
Nicholas Wade’s science story for the Times played it somewhat straighter, but still went for the sex angle with the headline “Signs of Neanderthals Mating with Humans”.
The distance from the more clinical “mating” to Bloch’s cartoon of a Neanderthal man holding a club offering flowers to a woman in a dainty skirt may seem like the span from science to popular imagination. But as UCSC Professor of Anthropology Diane Gifford-Gonzalez, Berkeley Anthropology Professor Margaret Conkey, and University of Southampton Professor Stephanie Moser have all shown in different ways, the science of human origins is drenched in the same images as the popular press.
So I have to ask: why is the man in Serge Bloch’s cross-species couple the Neanderthal? Shades of Clan of the Cave Bear! Apparently, in the popular imagination it takes a more evolved woman to make a husband out of a man…
The researchers sequencing Neanderthal DNA from three fragments of bone recovered from a Croatian cave have reportedly completed 60% of the Neanderthal genome. And while other researchers applaud the technical work done at the Max Planck Institute for Evolutionary Anthropology in Germany, they are cautious about the interpretation of the data.
The problems start with the proposed time and place for Neanderthal-human romance: not in the Europe of 40,000 to 30,000 years ago imagined in Clan of the Cave Bear, but in the Middle East, and at least 20,000 years earlier, maybe as much as 60,000 years before the period when we know Neanderthal and early modern humans co-existed in Europe. To quote the Times again, “There is much less archaeological evidence for an overlap between modern humans and Neanderthals at this time and place.”
The times draws the line of disagreement along disciplinary lines:
Geneticists have been making increasingly valuable contributions to human prehistory, but their work depends heavily on complex mathematical statistics that make their arguments hard to follow. And the statistical insights, however informative, do not have the solidity of an archaeological fact.
Archaeologists do have well-developed models for recognizing human and Neanderthal populations in Europe during their period of overlap through different stone tools and other cultural features. It is the lack of such well-defined models for the Middle East of 100,000 to 60,000 years ago that gives archaeologists pause.
As an archaeologist, I found the idea that archaeological “facts” have solidity interesting for other reasons entirely. Like the image of the club-toting Neanderthal with stubble on his chin, it is a commonplace of everyday understanding of my discipline. And it is not quite true, or not true in the way that writers think it is.
The image of “solid” archaeological facts stems from the idea that our discipline studies hard, visible things that everyone can agree about. And there are lots of things involved in every archaeological analysis. But we quarrel all the time about what exactly they mean; how best to measure them and quantify them; and how the solid things in archaeology relate to the not-so-solid theories we develop.
And increasingly, our studies are not limited to, or even dominated by, the “solid facts” of popular imagination of archaeology. Instead, archaeologists today may study microscopic grains of starch invisible to the naked eye, or the traces of past human actions like sweeping a dirt floor visible under a microscope, or simply the chemical traces left behind when people sit in one place or do some everyday task in a particular location.
So, are we “part caveman”? the question is meaningless. If the findings of the Neanderthal genome sequencing hold up, they will tell us that the history of humans and our closest relatives was even more intimate than many had thought.
But the popular image of the crude Neanderthal should long ago have been set aside, replaced by our understanding of this human species as a cold-adapted contemporary of early modern humans. The visible differences in Neanderthal stature and facial shape would not necessarily have given a contemporary human pause. Those humans occupied the caves of Europe that gave us the scene for our cave man image as much as Neanderthals did.
As Stephanie Moser has shown us, we have populated those caves in our professional and popular imagination... Less reflections of what the “solid facts” of archaeology tell us than mirrors reflecting our own vision of our past, the cavemen are us.

    Posted by on Sunday, May 9, 2010 at 10:08 AM in Economics, Science | Permalink  Comments (9)


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