Effect of prior interference upon retention of fixed-interval performance in rats.

Abstract

To test the hypothesis that retention decrements of fixed-interval (FI) performance (assessed by ratio of responses made during 1st half of interval to number made during entire interval) are due to proactive inhibition arising from pretraining on CRF, (continuous reinforcement), 55 rats were trained on a FI-1 schedule without any pretraining. Two groups were trained simultaneously and tested either 24 hr. or 25 days after training. Group 3 began training 25 days later and was tested 24 hr. after training to control for differences in age and in exposure to the drive schedule. Contrary to the hypothesis, longer retention interval led to a rise in 1st-half ratios when compared to either control group.