ABSTRACT
The initial suggestion that the effects of drugs on behavior might be due to alterations in stimulus control of responding came from a review of behavioral pharmacology by Dews (1958). In this paper, Dews suggested that the effects of drugs could depend on four classes of factors: (1) what the animal is (species and individual); (2) what the animal is doing (the response and its rate of occurrence); (3) what the environment is doing to the organism (i.e., the eliciting, reinforcing, or discriminative stimuli affecting it); and (4) what has happened to the animal in the past. Dews suggested further that many of the actions of chlorpromazine are determined by environmental (class 3) factors. More specifically, it was suggested that chlorpromazine may alter behavior by decreasing the discriminative control of behavior.
