Visual discrimination and response reversal learning by aphasic subjects.

Abstract

Nine aphasic and eight nonaphasic hospital patients were presented with a discrimination learning problem in which they had to learn differential motor responses to visual stimuli. Subjects first were reinforced for emitting response A in the presence of stimulus A, and response B in the presence of stimulus B. Then they were placed in a reversal situation in which they were reinforced for emitting response B in the presence of stimulus A, and response A in the presence of stimulus B. Results indicated that aphasic subjects had more difficulty than nonaphasies in both discrimination tasks. However, responses of most aphasic patients who did not learn the discrimination were not random but reflected strategies which resulted in substantial numbers of reinforcements. Aphasic subjects tended not to improve upon initial performance within treatment sessions, unless either stimuli or consequences for responses were changed. Clinical evidence is presented which indicates that subject impairments which appear in the experimental task also appear in subsequent clinical activities.