Graduation Semester and Year




Document Type


Degree Name

Master of Science in Psychology



First Advisor

Roger Mellgren


The partial reinforcement extinction effect (PREE) is traditionally observed in rats when on a partial reinforcement schedule in a runway, that is, they are more resistant to extinction (persistent) than those on a continuous reinforcement schedule. Behavioral Momentum is observed when, in an operant chamber, rats on the most dense reinforcement schedule show more persistence in responding during extinction (or other response disrupting manipulation). The purpose of this experiment is to combine the runway and operant chamber and discuss the outcome in terms both theories. Subjects were either on a continuous reinforcement schedule (CRF) or a partial reinforcement schedule (PRF) along with a variable ratio (VR) schedule of 3 or 12. Runtime, latency to bar press, and the number of bar presses emitted in extinction were measured. The VR3 results in a traditional PREE with the PRF/VR3 showing more resistance to extinction (shorter latency to bar press and more bar presses) than the CRF/VR3 group. On the other hand, the VR12 results in an effect consistent with the behavioral momentum prediction; more dense schedules (CRF/VR12) results in greater persistence (shorter latency to bar press and more bar presses) than the less dense schedules (PRF/VR12). The persistence of running was greater for the PRF/VR3 over the CRF/VR3 and also greater for the PRF/VR12 over the CRF/VR12. This is the standard PREE for both PRF and CRF groups, indicating that behavioral momentum does not fit well with the running dependent variable, but does provide an explanation for the latency to bar press and the number of bar presses dependent variables. If supported by future research this finding would resolve the apparent inconsistence of PREE and behavioral momentum approach (Pear, 2001).


Psychology | Social and Behavioral Sciences


Degree granted by The University of Texas at Arlington

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Psychology Commons