Date of Award


Degree Name

Master of Arts



First Advisor

Dr. Alan D. Poling

Second Advisor

Dr. Lisa Baker

Third Advisor

Dr. Jack Michael

Access Setting

Masters Thesis-Campus Only


The effects of chlorpromazine (0, 2, 6 and 10 mg/kg) on the acquisition of lever-press responding by rats were examined under conditions where reinforcement (food delivery) was immediate or delayed. Under the immediate reinforcement condition, water-deprived rats were exposed during 8-hr sessions to a fixed-ratio 1 schedule of food delivery without prior autoshaping or hand shaping. Under the delayed reinforcement condition, similar rats were exposed to a tandem fixed-ratio 1 fixed-time 8-s schedule of food delivery. Squads of eight rats were exposed to each delay condition and drug dose. For all subjects, responses on one lever produced food and responses on a second lever had no programmed consequences. Regardless of whether reinforcement was immediate or delayed , chlorpromazine reduced in dose-dependent fashion the mean number of operative-lever responses emitted, which suggests that the drug interfered with learning. Nonetheless, at all chlorpromazine doses except l 0 mg/kg, substantially more operative-lever than inoperative-lever responding occurred, indicating that the operant response was acquired. At 10 mg/kg, most subjects did not acquire lever-pressing regardless of whether they were exposed to the immediate or delayed reinforcement procedure.

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