Positive reinforcement of the barpressing response by a light stimulus following dark operant pretests with no aftereffect.

Abstract

Data from the bar-pressing responses of 76 albino rats supported the hypothesis that presentation of a light stimulus can reinforce an immediately preceding response following nonreinforced experience with that response. Statistically significant response increments were observed in five independent sets of animals. The influence of light per se and the possibility of adventitious secondary reinforcement effects were rejected on the basis of available data. The results were interpreted as offering support for the positive reinforcing powers of light stimulation under the experimental conditions used and as suggesting as one possible interpretation a kind of stimulus-change or novelty factor in reinforcement.