ABSTRACT
The principle of positive induction states that the occurrence of the negative stimulus of a discrimination during extinction serves to strengthen the conditioned response (CR) to the positive stimulus, thus slowing extinction. The negative stimulus interspersed between nonreinforced positive stimulus trials in an extinction series significantly retarded the extinction of the CR. It is believed that the fact of positive induction requires a modification in traditional theories of discrimination learning. According to I. P. Pavlov the occurrence of the negative stimulus in a discrimination has the inductive effect of strengthening the excitability of the focus of the positive one on the cortex. Therefore, it is harder to extinguish the response to a positive stimulus by nonreinforced trials if presentations of the positive stimulus are alternated with those of the negative stimulus than if only a succession of positive stimuli is administered.
