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That basically summarizes coverage of a recent study on songbirds' "artificial grammar system". More on that later. First, a summary of the study:
An influential hypothesis, put forward by Noam Chomsky and colleagues, is that one ability - recursion - enables language, and that humans are alone in having this capacity. Two Japanese researchers (Abe and Watanabe) found a trace of this ability in a songbird species, thereby adding fuel to the debate about the uniqueness of humans. They found that songbirds could, using artificial grammar rules, recognize an ‘ungrammatical' sequence from a mix of birdsongs. The researchers also identify a specific brain pathway for this ability, providing new impetus for research into the biological origins of linguistic aptitude.
Unfortunately, the press' reaction to the study (such as this New Scientist article, which doesn't even mention the term recursion) entirely misses the point: the focus is on the fact that 'grammar' was learned, but not on the nature of the grammar learned. Grammar (loosely defined) is commonplace, recursion is not - any demonstration that non-human animals have innate recursive ability would revolutionize biolinguistics.
So what is recursion? It's a (rather elegant) mathematical concept applied to language. Like all science, the definition is contested. But here's a working definition handed down to me by a mathematical biolinguist: Because clauses (e.g. "Holmes studied the footprint") can always be embedded in the next clause (e.g. "Watson said that Holmes studies the footprint") which can then be returned for the next combination (e.g. "I read that Watson said that Holmes studied the footprint"), the set of sentences and clauses that can be generated is technically infinite. Recursion, in sum, allows language to become an infinite system.
Abe and Watanabe's study shows that songbirds are able to process a recursive grammar - this is perhaps the most significant aspect of their paper. It therefore questions the 'uniqueness' of our species and shows that, to some extent, the characteristics of human language are more deeply shared than previously thought. It similarly has substantial implicaitons. First, it establishes (or at least invigorates) a line of research into the neurological origins of syntax. In particular, it points to the basal ganglia as influential in the evolution of syntax. Second, it goes some way towards unravelling the processes behind formal grammar acquisition, possibly adding to language learning models in children.
But this shouldn't be overstated - an essential part of Chomsky's argument is that recursion is innate. Abe and Watanabe have simply demonstrated that recursion may be learned. So biolinguistics has yet to be revolutionized. But this also makes these small advances exciting, important and befitting of more nuanced presentation.
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Hauser, Chomsky and Fitch. The faculty of language: what is it, who has it, and how did it evolve? Science 2002.
Abe and Watanabe. Songbirds possess the spontaneous ability to discriminate syntactic rules. Nature Neuroscience 2011.
