Conceptual deficits and aging: the Category Test.

Category Test performance of 41 bright aged normals was compared with the performance of 40 young normals and a group of 43 patients with suspected neurological dysfunction. The aged normals were not only as deficient as the neurologic patients but showed a similar pattern of deficits on Category subtests. The extreme difficulty experienced by aged normals and patients on Subtests III and IV was explained as a function of task complexity rather than of conceptual difficulty of conceptual principles and task complexity in a variety of impaired groups was suggested.