Abstract
Twelve male albino rats were reinforced for lever press durations of 0.5, 1.0, 1.5, 2.0 and 2.5 seconds. Half of the subjects (F) received an auditory feedback after non-reinforced responses. The 6 other (Controls, C) worked without feedback. F rats emitted on the average higher mean response durations and earned more reinforcements than C subjects. The standard deviation and coefficient of variation of their response duration distributions were significantly lower than those of group C. These results tend to show that feedback stimulus following non-reinforced responses improve the accuracy of performance in the response duration differentiation schedule.