Recursion in vocalization not unique to humans

Several years ago Marc Hauser, Noam Chomsky and Tecumseh Fitch published an influential paper that speculated that recursion, or self embedding, might be the one aspect of language that is clearly unique to humans. Gentner et al have now shown that the European starling can be trained to recognize complex recursive grammars. A review by Marcus suggest that "the abstract computational capacity of language may consist not so much of a single innovation as a novel evolutionary reconfiguration of many.. ancestral cognitive components, genetically rejigged into a new whole. Contemporary research suggests that the human brain contains few if any unique neuronal types, and few if any genes lack a significant ancestral precedent."