DIFFERENTIAL MAGNITUDE OF REWARD CONDITIONING AS A FUNCTION OF PREDIFFERENTIAL REWARD MAGNITUDE.

24 MALE HOODED RATS WERE CONDITIONED TO A PERFORMANCE ASYMPTOTE WITH EITHER 12- OR 1-PELLET REWARDS IN BOTH BLACK AND WHITE RUNWAYS. 1/2 OF THE 1-PELLET SS CONTINUED UNDER THE SAME CONDITIONS WHILE THE REST OF THE SS WERE REWARDED WITH 12 PELLETS IN 1 RUNWAY AND 1 PELLET IN THE OTHER. SS TRAINED ON 12 PELLETS SHOWED LARGE NEGATIVE-CONTRAST EFFECTS IN THE 1-PELLET RUNWAY WHILE SIMILAR EFFECTS FOR THE SS TRAINED WITH 1 PELLET WERE MUCH SMALLER AND LIMITED TO THE EARLY SECTIONS OF THE RUNWAY. RESULTS ARE DISCUSSED AS SUPPORTING A FRUSTRATION THEORY IN WHICH THE ONSET OF STIMULI AASOCIATED WITH REWARD REDUCTION ELICIT AN UNCONDITIONED EMOTIONAL RESPONSE RATHER THAN AN ANTICIPATORY RESPONSE.