Abstract
Six groups of albino rats were trained under hunger motivation in either jumping, climbing, or running, in a short black box under 50% or 100% reinforcement. Performance under 50% reinforcement was slower than that under 100% reinforcement during the early trials, but faster by the end of training. Motivation was then changed to thirst and all Ss received 32 acquisition trials and 32 extinction trials in a long white runway. Resistance to extinction for Ss partially reinforced in jumping or running was greater than for continuously reinforced Ss; whereas Ss partially reinforced in climbing were less resistant to extinction than any other group. The results support predictions derived from Amsel''s account of the PRE (partial-reinforcement extinction), and indicate that a positive or a negative PRE can be sustained through continuous reinforcement, changed motivation, and changed response.