Escape learning as a function of amount of shock reduction.

Several studies (Crespi, 1942; Zeaman, 1949) have shown that performance in instrumental appetitive conditioning is directly related to the magnitude of reward contingent upon the response. Moreover, these studies have indicated that shifts in amount of reinforcement (amount of food or water) lead to rapid and appropriate changes in performance level. The results of a study by Campbell and Kraeling (1953) provide evidence that magnitude of reward is an important variable affecting performance in instrumental escape conditioning. Rats were run in a straight alley in which the startbox and runway provided a continuous 400-v. shock and the goalbox either 300-, 200-, 100-, or 0-v. shocks. Running speed was faster the greater the reduction in shock intensity at the goal. The present study sought to extend these findings on the role of magnitude of reinforcement in escape learning. Specifically, the purpose was to determine whether shifts in the amount of shock reduction would produce changes in escape performance similar to those found in appetitive conditioning with shifts in the amount of goal substance. This question was assessed by training rats initially at one level of shock reduction and then shifting them to different levels during a subsequent testing phase.