  As Marcus (2004:40-45) points out in response to Elman et al. 1996, the ability of the brain to ‘rewire’ itself under exceptional circumstances is consistent with its having been ‘prewired,’ or set up, differently by the genes. However, these sorts of data indicate that complex functions, such as are involved in processing sign language, can be carried out in areas of brain that are ‘prewired’ (if they are) to do something quite different.  This suggests that these abilities require little in the way of task-specific pre-wiring, and are learned largely on the basis of experience (together with whatever sort of 'prewiring' is supplied for the cortex as a whole). That is, if sign language processing tasks can be carried out by areas of cortex that are presumably innately predisposed (if they are) to do auditory processing, then the former competence must be being learned in the absence of inborn constraints or knowledge that are specific to that task. Of course, these are pathological cases, and it is unclear whether the subjects in these experiments had any special training in order that their brains were ‘rewired’ in these ways. Nonetheless, examples like these provide an existence proof of the brain's ability to acquire complex processing capacities — indeed, processing capacities relevant to language — in the complete absence of inborn, domain-specific information. As such, they raise the possibility that other aspects of language processing are similarly acquired in the absence of task-specific constraints.