This article discusses the neuropsychological profile of Parkinson's disease from the perspective of cognitive theory, anatomical organization, and unit recording data. Despite the point of origin, methodologically controlled studies are converging to support the position that patients with this disorder suffer selective impairment in the acquisition of novel tasks which rely on internal (subjective) processing for the efficient establishment of new cognitive "habits." The roles of attention and learning as well as of unit activity within the relevant networks are considered. Also included are recent but important concepts from personality theory which potentially enhance understanding of the neuropsychology of Parkinson's disease.