According to some big names in linguistics and evolutionary biology (Hauser, Lewontin, Chomsky, etc.) not very much.
Two things to talk about here:
1. The claims of the article, which I find very well argued for, but not (at least to me) very surprising.
2. Is it surprising to anyone that Mark Hauser is collaborating in a such a prominent piece of research?
Re. 2: Yes! And I’m not sure how we, as readers, should respond. Clearly, this is a high-profile attempt to wield influence and set a research agenda. In some ways, these authors are well qualified to write such an article. But can we take it seriously, if Hauser is first author? Does it deserve to be taken seriously?
Re. the claims of the article: I think it’s easy to be sceptical about virtually any hypothesis regarding human evolution. Reconstructing what happened to a single lineage after its divergence from other extant lineages is a hard problem. When that lineage happens to be our own lineage (i.e. one in which evolution has produced a number of unique cognitive, behavioural and social capacities) we have a very hard problem. And when we’re talking about a capacity that may well have evolved after our divergence from all other hominin lineages, as in the case of modern human language, we have a problem that is harder still. Even so, hypotheses are constrained by evidence in all sorts of ways. While there are usually various competing hypotheses regarding the evolution of any human trait, including language, it is in no way a trivial exercise to come up with a hypothesis that is empirically and theoretically credible. Archaeology, anthropology, psychology and economics are all sources of constraint, even though the evidence is inconclusive.
The following recent paper by Sterelny is, in my view, an excellent example of how relevant evidence can be brought to bear in the case of language:
http://rstb.royalsocietypublishing.org/content/367/1599/2141.short
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The authors are right, I think, to be a bit sceptical but the paper has some problems. It’s right to focus on what evolved; the central claim is that what evolved is some “recursive” ability but the word “recursive” is highly ambiguous, and the authors never make clear what they mean by this problematic term.
Does it just mean the ability to form “discrete infinity”; or does it mean “recursion” in the sense of Turing computable?
There are some good papers by Marcus Tomalin on this issue.
These are two completely different hypotheses, and neither of them seem to support the inferences that the authors draw from them. e.g. “From these formal systems it is possible to deduce linguistic universals as consequences, thereby generating empirical predictions.”
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There is a growing body of research on the FOXP2 gene. It is involved with other abilities besides language, but this would only be surprising or relevant if you’d already drunk the Chomskyan cool-aid. More generally, if you make it a matter of definition that language is this magical thing, then it’s not surprising you won’t get much understanding from neuro-science or evolutionary theory. That is, I very much doubt any natural being could evolve language as Chomsky describes it, but this just provides more evidence for competing frameworks.
Since 2003 there has been interesting work on brain structure and predicate-argument structure (http://www.lel.ed.ac.uk/~jim/newro.htm) which strongly suggest how modern languages could have developed out of non-linguistic mental abilities. Of course nobody is anywhere near explaining exactly how such a development might work (and a lot is going to depend upon how central you think predicate argument structure is to natural language syntax), but it doesn’t seem to require anything particularly mysterious unless you start with a syntactic theory that is unconstrained (to the extent that it is provably recursively enumerable).
Note: I haven’t read the article yet. But I’d be very surprised if this isn’t what’s going on, because this is what’s always going on when Chomsky takes on evolutionary theory.
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I agree with Jon (and maybe this is lurking in Alex’s worries about ‘recursion’ too) that there is a danger of assuming that human linguistic abilities are magical and then finding it forever hopeless that we find an evolutionary account of it. I’m not sure the article leans that heavily on that part of the argument, however.
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A view from a linguist: I think the biggest problem that many linguists will have with this paper is that it implies that the study of language evolution must be limited to the study of discrete infinity. Assuming this, it’s an obvious point that a lot more needs to be learned before we can describe the evolution of this trait (although banishing fields from the study of language evolution is a bit over the top).
However, there are many other contenders for what the object of study should be, and a big debate about whether linguistics should focus on aspects of competence or aspects of performance. For example, others take evolutionary approaches to predicate argument structure (mentioned above), the capacity for massive storage, joint attention, social structure or universals of conversational infrastructure. Interestingly, I get the impression that people focussing on these topics work together, while the Hauser paper is very hostile to any other possibilities.
It would be very nice to know more about discrete infinity, and the overall message of the paper for other fields seems to be “carry on doing what you were already doing (but keep off our turf)”. However, even if we understood everything about the process that lead from genes to neural structures that implement recursive operations, for me this would only be a small part of the explanation of why we communicate the way we do. Even for Hauser et al., I suspect that an explanation of why the trait evolved would need to incorporate other perspectives.
I’ve written a more detailed response (as well as some criticisms of the general argumentation) here:
http://www.replicatedtypo.com/the-mystery-of-language-evolution
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