ABSTRACT
A clinician assessing an aphasic patient without knowing that the patient is illiterate may erroneously diagnose alexia and agraphia. Although this example is overly simplistic, can we be sure that all the measured impairments are attributable to the aphasia or could they be due in part, either directly or indirectly, to a premorbid lack of literacy training? The clinician is unable to answer this question because there are no norms for illiterate patients in the aphasia or neuropsychological batteries. Clearly, we first need to understand how the development of literacy impacts on cognitive processing as a whole before focusing on the aphasia population. Then we will be able to focus on the intriguing interaction between language lateralization and localization and learning a writing system. This is one instance of the potential influence of a social factor on biological characteristics.
