Anthropology.net and New Scientist have recently reported on a couple of developments in the Neanderthal language debate.
Firstly, a new paper is in the works that will cast doubt upon the conclusions of the now famous Neanderthal FOXP2 paper from last year. Krause et al found the same adaptive variation of the language-implicated FOXP2 gene as is found in humans in Neanderthal DNA sequences, and claimed that the this was evidence for FOXP2 as a homologous trait that was present in our common ancestor. Cue endless headlines about how this finding is proof that Neanderthals had language.
Thanks to a talk by D’Errico at Evolang (post upcoming) I do believe that Neanderthals had some sort of fairly sophisticated vocal communication, but this based on the archeological record rather than the presence/absence of FOXP2. As many commentators noted at the time, the presence of FOXP2 is not proof of language. Firstly, FOXP2 is by no means the sole gene responsible for language. Secondly, the role of FOXP2 in producing language is far from clear, another paper last year found similar adaptive variation in echolocating bats and suggested it might more likely be a gene for co-ordinating orofacial movement. Certainly FOXP2 is a gene whose main role is the activation/deactivation of other genes.
Well an as yet unpublished paper is apparently going to take issue with one of the main claims of the original study, namely that this finding was consistent with a homologous adaptation in the common ancestor of humans and neanderthals. Here’s the abstract:
Krause et al. (2007) recently examined patterns of genetic variation at FOXP2 in two Neandertals. This gene is of particular interest because it is involved in speech and language and was previously shown to harbor the signature of recent positive selection. The authors found the same two amino-acid substitutions in Neandertals as in modern humans. Assuming that these sites were the targets of selection and no interbreeding between the two groups, they concluded that selection at FOXP2 occurred before the populations split, over 300Kya. Here, we show that the data are unlikely under this scenario but may instead be consistent with low rates of gene flow between modern humans and Neandertals. We also collect additional data and introduce a modeling framework to estimate levels of modern human contamination of the Neandertal samples. We find that, depending on the assumptions, additional control experiments may be needed to rule out contamination at FOXP2.
A very simple explanation for the presence of FOXP2 in neanderthals would be that there was some sort of interbreeding between the species. The original paper made the broad assumption that interbreeding did not take place between humans and neanderthals on the basis of the fact that other randomly selected genes were undisturbed and the selective sweep for the FOXP2 gene came after our common ancestor. At the time people like John Hawks expressed a cynicism about the strength of this assumption. The writers of this new paper argue that the evidence presented in the original paper does not imply a homologous adaptation in a common ancestor. They argue that it is consistent with low level interbreeding, but the lack of definition means that we cannot also rule out the possibility that it got there from human contamination. An interesting prospect.
On a similar note Robert McCarthy, an anthropologist at Florida Atlantic University, has used models of the Neanderthal vocal tract to try and simulate what Neanderthals sounded like. He has even made a ‘recording’ of a neanderthal pronouncing a vowel sound. McCarthy argues that neanderthals lacked the capacity to produce the basic human quantal vowels, thus seriously impeding their ability to use language.
In contrast to a modern human “E”, the Neanderthal version doesn’t have a quantal hallmark, which helps a listener distinguish the word “beat” from “bit,” for instance. Though subtle, the linguistic difference would have limited Neanderthal speech, McCarthy says.
I’m very dubious that this proves anything about neanderthal language. Firstly, who says it evolved in the same way as humans? Secondly it is based on a fairly narrow set of evidence, expanding upon the work of Lieberman, who argued that neanderthals had impaired language ability. It might add some weight to the idea of a limited langauge faculty, but I don’t think it can really be used to argue that this rules out language in neanderthals.