Stimulus efficacy, chlorpromazine, and schizophrenia.

Stimulus efficacy can be defined in terms of rat least two variables: Proximity of a stimulus to reinforcement and the association of a stimulus with reinforcements of different magnitudes. The behavioral effects of chlorpromazine were found to be significantly modulated by stimulus efficacy and increases in efficacy attenuated drug effect. The relevance of this finding to various conjectures about the deficits seen in schizophrenia is discussed.