Monday, November 24, 2008

That Time of Year...

It's late November here at McGill, which means two things: snow is coming (in fact, it's coming down right now! argh!), and soon-to-graduate undegraduate students will soon be sending off grad school applications. When my students ask for advice about graduate school in archaeology, I usually refer them to this excellent overview about applying to grad school to do archaeology written by Keith Kintigh, of my old department (ahem, I mean school) at Arizona State University.

Now, I will certainly also be pointing them out to this 'disclaimer' found on the web site of Sönke Johnsen's lab.

Hat tip: Coturnix.

Friday, November 21, 2008

Empirical Insights into Prehistoric Social Organization

So, by now, you've probably heard more than you care to hear about the discovery of the oldest nuclear family in one of a series of multiple burials discovered at the Neolithic Corded Ware Culture site of Eulau, which dates to about 4,600BP (Haak et al. 2008). Most of the media hoopla surrounding the publication of this discovery has centered on the notion of 'nuclear family.' Fair enough, it's something that most denizens on the web and most newspaper readers will readily relate to, which - especially for the 'traditional family values' crowd - is a good way to pitch a legitimate and relatively groundbreaking scientific discovery. In my view, however, this frenzy over the identification of a nuclear family organization has drowned a much more important and far-ranging conclusion of this paper...

As luck would have it, I was introducing my 'Archaeological Methods' students this week to the wonders of cognitive archaeology, whereby archaeologists attempt to understand the motivations and social organization of long-lost groups and individuals. The paper by Haak et al. (2008) featured extensively in the lecture - indeed, I may have overenthusiastically declared that I was "in love" with this paper. The reason I was so enthused about this paper is encapsulated in this figure (Haak et al. 2008: Figure 5) of the paper, which summarizes the results of the strontium isotope analysis.

In a nutshell, the male symbols indicate the strontium signature of adult males, circles indicate those of children, while female symbols indicate those of females. By way of background, strontium isotopes derive from the soils of a region and are stored in teeth during childhood as resources collected from that soil were consumed. Because of that they are different between individuals or groups of individuals that come from areas with distinct geological substrates. In this case,there is a clear separation between the females' overall signature and that of the other individuals, which indicates that males and children have signatures similar to that of the geological substrate of Eulau, while the females display a signature more concordant with that of Paleozoic deposits found in the Harz Mountains, about 60km distant from Eulau. That may not seem like a huge distance, but for relatively sedentary folks like the Neolithic agriculturalists of Eulau, this means that they probably grew up as members of other social groups located near the Harz Mountains.

Why is this significant? Because it provides some empirical evidence for the fact that the Neolithic people of Eulau had an exogamous, patrilocal system in place whereby women from a distant area would come live with men who lived their whole life in the Eulau region, where they would raise the children they had with them (as demonstrated by the DNA analyses that form the basis of the 'nuclear family' claim). So these groups were exogamous, in that they selected mates/married outside their group, and they were patrilocal, in that the basic reproductive unit/family lived in the vicinity of where the males had grown up. To me, this is incredibly fascinating in that it allows archaeologists to make empirically grounded inferences about domains of Neolithic life that are usually thought not to be accessible to prehistorians. Indeed, this allows us to talk objectively about aspects of prehistoric social behavior, which is tricky indeed to speculate about in most cases. We may yet be getting to the point where we can show that archaeology is anthropology.... Binford would be proud!


Haak, W., G. Brandt, H.N. de Jong, C. Meyer, R. Ganslmeier, V. Heyd, C. Hawkesworth, A.W.G. Pike, H. Meller, and K.W. Alt. 2008. Ancient DNA, Strontium isotopes, and osteological analyses shed light on social and kinship organization of the Later Stone Age. PNAS 105:18226-18231. doi: 10.1073/pnas.0807592105

Thursday, November 20, 2008

Cannibalism at Zafarraya?

The site of Zafarraya (or in full Cueva del Boquete de Zafarraya), in southern Spain, is most famous for having yielded the most recent radiometrically dated Neanderthal remains known to date (Hublin et al. 1995, Barroso Ruiz and De Lumley 2006). This is in contrast to Gorham's Cave, Gibraltar, which has been claimed to contain the most recent Mousterian assemblages known to date (Finlayson et al. 2006; cf. Zilhao and Pettitt 2006).

Cecilio Barroso Ruiz, one of the investigators who excavated Zafarraya, has given a short interview about some of the material that has been found at the site. He interprets the lithic and faunal material as suggesting that the site was occupied between 30-27,000 BP as a camp from which Neanderthals would hunt mountain goats. Barroso Ruiz also suggests that climate should be ruled out as the main cause of the disappearance of the Neanderthals since Mediterranean conditions would have prevailed around the site throughout that period.

One of the more provocative interpretations he proposes, however, is that the site has yielded "indisputable" evidence of Neanderthal cannibalism:

During the excavation, that took place in two stages - between 1981-1983 and between 1990-1994 - two femora and a tibia belonging to a female and a small male mandible were recovered, all of which bear "irrefutable" traces of cannibalism. "They would begin by taking the body apart, removing the meat, and after having eaten it, they would throw the bones in the fire where they would burst" explains Barroso. During analysis (that involved the participation of 90 specialists), the bones were pieced back together, bringing to light the cut marks of cannibalistic practices. "It has been said that Neanderthals buried their young, but we have shown that this wasn't the case here, since they appear to have been used as food following their death" concludes the archaeologist. (my translation)

In light of a recent study that argues against the case for cannibalism at Krapina, Croatia, such claims from Zafarraya take on a new importance. Interestingly, if the case for cannibalism at El Sidron (Rosas et al. 2006) is eventually demonstrated unambiguously, it might suggest that cannibalism might have been somewhat more common than elsewhere in the Iberian peninsula towards the end of the periods during which recognizably Neanderthal remains are documented in the fossil record.

Hat tip: Martin Cagliani.


Barroso Ruiz, C., and H. de Lumley (eds.). 2006. La Grotte du Boquete de Zafarraya (Malaga, Andalousie) vol. 3, Junta de Andalucía, Consejería de Cultura, Sevilla.

Finlayson, C, Giles Pacheco, F, Rodríguez-Vidal, J, Fa, DA, Guiterrez López, JM, Santiago Pérez, A, Finlayson, G, Allue, E., Baena Preysler, J, Cáceres, I, Carrión,
JS, Fernaández- Jalvo, Y, Gleed-Owen, CP, Jimenez Espejo, FJ, López, P, López Sáez, JA, Riquelme Cantal, JA, Sánchez Marco, A, Giles Guzman, F, Brown, K, Fuentez, N, Valarino, CA, Villalpando, A, Stringer, CB, Martinez Ruiz, F & Sakamoto, T 2006.
Late survival of Neanderthals at the southernmost extreme of Europe. Nature 443:850-853.

Hublin J.J., Barroso Ruiz C., Medina Lara P., Fontugne M., Reyss J.-L., 1995 - The Mousterian site of Zafarraya (Granada, Spain): dating and implications on the palaeolithic peopling processes of Western Europe. C. R. Acad. Sc. Paris. 321 (IIa): 931-937

Rosas A, Martínez-Maza C, Bastir M, García-Tabernero A, Lalueza-Fox C, Huguet R, Ortiz JE, Julià R, Soler V, de Torres T, Martínez E, Cañaveras JC, Sánchez-Moral S, Cuezva S, Lario J, Santamaría D, de la Rasilla M, and Fortea J.2006. Paleobiology and comparative morphology of a late Neandertal sample from El Sidron, Asturias, Spain. PNAS 103:19266-19271.

Zilhão, J., and P. Pettitt. 2006. On the new dates for Gorham's Cave and the late survival of Iberian Neanderthals. Before Farming 2006/3:3.

Thursday, November 06, 2008

Blogging for Science

Here's my quote of the day, courtesy of PZ Myers:
Peer review is only a first, preliminary hurdle for a paper to cross; passing peer review and getting published does not mean that your work is right. Some incredibly awful papers get through the review process, somehow. Getting published only means that now your paper is going to be opened up to wider criticism. Don't take the attitude that publication means vindication; I know reviewers, and I've reviewed papers, and I know that reviewers are sometimes lazy, sometimes susceptible to croneyism, and always overworked, and that publication doesn't mean you are right. (my emphasis).
Boy, don't I know it! Publishing paleoanthropologically-themed research can sometimes feel like you're entering the Thunderdome, a lesson I learned first-hand in my very first peer-reviewed publication! And Myers makes a good point: when something gets published, it only means that it's serious enough that other experts in the field recognize it's worth discussing, that other professionals can now have a go at it, if you will. Actually you should read the whole post, which is about how people think of blogs, comments on blogs, and the contribution this can make to scientific discourse. It's a thoughtful piece, and one in which PZ - whose writing style can occasionally be, errr, fiery - cogently lays out the case for the usefulness of blogging to make scientific research and its conclusions accessible to a wider audience.

And as for the writing style of blog posts, I also especially liked this quote (which came in second place for quote of the day): "Explain your answers as you would to an undergrad or bright high school student. If you can't, it implies that you aren't looking for an equal opportunity, you are looking for a way to avoid probing questions." Now, that doesn't mean you need to 'dumb it down' or that everybody needs to do this. In my view, it highlights how the web can be used to democratize and favor the diffusion of science. After all, in a time when funding for scientific research increasingly comes from public agencies, it is important to present our work in a manner that is accessible to a well-educated public. This is part of why I have this humble little blog here.

And because common ideas seem to strike different people at the same time, check out John Hawks' recent post on the issue. His take? "I wanted to point to Orac's post, since it is what the blogosphere is the best for: clear, factual critiques that focus on methods." And it's fitting that I mention Hawks here, since he was one of the parties in one of the best 'real-time' virtual debates on Early Upper Paleolithic chronology, a topic near and dear to my heart. On January 12, 2007, John blogged about a new Science paper on the EUP chronology of Kostenki, Russia, criticizing some aspects of the paper's conclusions. Four days later, on January 16, 2007, one of that study's authors, John Hoffecker wrote a reply to Hawks' post, posting it on Kris Hirst's Archaeology Blog, addressing in a detailed manner some of John's critiques. And two days later, on January 18, you guessed it, Hawks had also posted a lengthy reply to some of the points raised in Hoffecker's guest post, situating the debate in a broader context to highlight the significance of the paper he originally blogged about.

OK, lengthy summary to basically highlight that, in the span of just over one week (literally, a blink of an eye in 'journal time'), you had a serious, thought-provoking and scholarly back-and-forth debate on a paper that had just been published. If this had taken place in Science itself, it would have probably taken at least 6 months to get published, far after the paper had faded from public consciousness. Now, this would be all and well for the paleoanthropological community, but for the public at large who might have been interested in the issue, it probably provided a rarely seen instance of how scientists can disagree on details (the specifics of the chronology of the 'transition') while nonetheless agreeing on fundamental issues (that the transition was an important process in recent human evolution). So, yes, blogging can and does serve a very useful purpose in the discourse of science.