Language change, diffusion, and more early dates from South America

I've read a melange of interesting articles in the last couple of days instead of reading the term papers I'm supposed to be grading. Actually, I've been doing both, in between meetings of various kinds.

This first article may seem a little off-topic, but I think it is directly relevant to prehistory.

Dunn, Michael, Simon J. Greenhill, Stephen C. Levinson, and Russell D. Gray (2011). Evolved Structure of Language Shows Lineage-specific Trends in Word-order Universals. Nature 473, 79-82.

Published yesterday, this article tests hypotheses, originally posed by Chomsky and Greenberg, about the innate structures of language by studying how languages have changed through descent within language families. The authors studied four of the larger language families, Austronesian, Indo-European, Bantu, and Uto-Aztecan, to see if certain kinds of changes co-occurred, which would imply that those characteristics were cognitively or neurologically linked. Interesting, the authors found little evidence for either Chomsky's or Greenberg's hypotheses, and conclude that "[l]inguistic diversity does not seem to be tightly constrained by universal cognitive factors specialized for language. Instead, it is the product of cultural evolution, canalized by the systems that have evolved during diversification, so that future states lie in an evolutionary landscape with channels and basins of attraction that are specific to linguistic lineages." (p. 82). This seems to me to be an eminently sensible conclusion that harmonizes with my own knowledge and experience of language and historical linguistics. In individual cases, it is easy to see how specific changes to languages are strongly constrained and conditioned by their linguistic and cultural contexts, so the results of the analysis are not surprising. As an aside, I think that Otomanguean would have been a better choice than Uto-Aztecan for this study because the former is larger (in terms of numbers of daughter languages) and its evolution is less confounded by the effects of later migrations.

Since we're talking about linguistics, I want to mention an article by the famous linguist William Labov (Labov, William 2003. Pursuing the cascade model. In D. Britain and J. Cheshire (eds). Social Dialectology: In Honor of Peter Trudgill. Amsterdam: John Benjamins. Pp. 9-22). Very interesting! He assembles evidence that lexical diffusion tends to jump from larger cities to smaller ones in rank order, rather than diffusing outwards like waves from centers of innovation. This is modeled using the gravity model from geography, which has also been applied in archaeology. I had no idea that the gravity model had been applied in this manner. This also has implications for models of diffusion in archaeology.

Finally, a bit of pure archaeology:

Jolie, Edward A., Thomas F. Lynch, Phil R. Geib, J. M. Adovasio (2011). Cordage, Textiles, and the Late Pleistocene Peopling of the Andes. Current Anthropology, Vol. 52, No. 2, pp. 285-296.

They directly dated textiles and cordage from Guitarrero Cave in Peru to ~12,000 cal yr B.P. "Direct dating" in archaeology means they actually dated the artifact in question, rather than an associated object, such as a lump of charcoal in the same feature or stratum. Guitarrero Cave is a pretty well-known site that had previously produced some unusually early--pre-Clovis--radiocarbon dates. The site is located in an intermontane valley in the Andes and is known for its Archaic/Paleoindian (?) occupation. The new dates as well as corrections applied to older ones suggest the earliest occupation dates from 12,100-11-800 cal yr B.P. This is not as early as Monte Verde, Chile, but it is still pretty early.