The potentiation of conditioned reinforcement by psychomotor stimulant drugs. A Test of Hill's Hypothesis

Abstract

A test of Hill's hypothesis that psychomotor stimulant drugs potentiate the effects of conditioned reinforcement (CR) was made, using a choice paradigm in extinction, with several doses of pipradrol. In Experiment 1 it was found that a dose of 10 mg/kg pipradrol increased responding on a lever providing CR, but depressed responding on a lever providing no CR (NCR). Experiments 2 and 3 tested whether the drug enhanced reinforcing rather than unconditioned properties of the CR stimulus. Evidence was in favour of the former, but certain results supported the existence of other factors which might contribute to the potentiation effect. Finally, in Experiment 4, the factors contributing to the failure of some animals to show stimulation of operant behaviour following pipradrol, were examined. © 1975 Springer-Verlag.