  However, there are two difficulties with this scenario. First, there  is evidence that the power of recursion posited by Hauser et al. as  being distinctive of the human FLN is in fact not distinctive to  humans, because it is not species specific. (See Esser, et al. 1997 and McGonigle, Chalmers and Dickinson, 2003.) Second,  recursiveness is not language specific either, but is a feature of  other domains of human cognition and endeavor as well. Our conceptual space, for instance, appears to be hierarchically ordered (poodles  are a kind of dog, which are a kind of quadruped, which are a kind of animal, etc.). Similarly, the planning and execution of  non-linguistic actions seems often to involve the sequencing and  combining of smaller behavioral units into larger wholes. Recursion  might well be an important part of the human language faculty, but  it's apparently not specific either to us or to that faculty. Or, to  put the point more bluntly: if it's Chomsky's view that recursiveness is the pivotal feature of the language faculty, and if recursiveness  is a feature of human cognition and action more generally, then it's  not clear that Chomsky remains a linguistic   nativist.[26] 