  Vargha-Khadem speculates (cf. Watkins et al. 2002:463) that those of the KE's deficits that do not appear to be motor related (e.g., their comprehension and reading problems, their difficulties with word  order and syntax) are a result of impaired learning that itself  results from their motor deficits. For instance, impaired  articulation could lead to impoverished phonological representations, which would then impair the acquisition of morphological and  morphosyntactic knowledge, which would then constitute a poor basis  for further syntactic learning. Impaired representation at all of  these levels would then express itself in receptive language and  reading, as well as in the realm of spoken language. Another possible explanation of the KE's non-articulatory deficits, which is not  necessarily in competition with the previous one, derives from the  fact that the basal ganglia are also known to be implicated in  working memory (Bosnan 2004) and reward-based learning (e.g.,  classical conditioning) that is mediated by dopaminergic circuits  that interact with basilar structures (Lieberman 2002). If  reward-based learning and working memory are impaired in the KE's,  then this could explain not only their higher-level syntactic  deficits, but also their overall lower IQ (Lieberman 2002).