Date of Award


Degree Type


Degree Name

Doctor of Philosophy in Psychology



First Advisor

Nelson F. Smith


The experiment collected both molar and molecular data to compare the effect Differential Reinforcement of Other Behavior (DRO), Fixed Time (FT), Variable Time (VT), and Extinction (EXT) schedules of reinforcement have on decreasing the frequency of a trained response in rats. The purpose of comparing these schedules was to investigate the relationship between responses and reinforcements in order to determine whether contingency theory or contiguity theory explains the differential effects frequently reported in the literature. Collecting data at both the molar and molecular level allowed a more conclusive theoretical explanation of the suppressive effects seen with these schedules. The experiment consisted of an eight session acquisition phase during which all animals were exposed to a FI 20 sec schedule of reinforcement. During the 15 session treatment phase the subjects were separated into ten groups consisting of a Fr 10 sec, Fr 20 sec, Fr 30 sec, EXT, VT 10 sec, VT 20 sec, VT 30 sec, DRO 10 sec, DRO 20 sec, and DRO 30 sec conditions. Finally, during the reacquisition phase all treatment groups were again exposed to a FI 20 sec schedule for 30 minutes. Molar analyses of the data showed that during the treatment phase the greatest response suppression was seen for the ORO and EXT treatment groups with only limited response elimination effects for the FT and VT treatment groups. A molar analysis of response-reinforcement interval data showed an increase for the FT and VT treatment conditions whereas a molecular interpretation of response-reinforcement intervals showed an increase in contiguity for the ORO animals. During reacquisition recovery of responding to pre-treatment levels was evident for all groups with the slowest resurgence of responding observed in the EXT, then DRO and finally the Fr and VT animals. The benefits and implications basic research has for applied settings were discussed.



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