Date of Award:


Document Type:


Degree Name:

Master of Science (MS)



Committee Chair(s)

Carl D. Cheney


Carl D. Cheney


J. Grayson Osborne


Animals performing on simple fixed-ratio (FR) schedules typically pause after reinforcement delivery. The present study demonstrated systematic control of pause length in multiple fixed ratio schedules by manipulating FR size and reinforcement magnitude. In Experiment I, two adult male rabbits were stabilized on an alternating, two component, multiple FR 10 FR 10 schedule. Different colored lights were correlated with both FR components. Stability was determined and mean pause lengths were calculated as one FR component was increased in size until the schedule was FR 10 FR 50. Pausing was longer before the large FR component and was positively correlated with increases in FR size. Schedule and stimulus control were demonstrated by randomizing the order of FR presentations and by reversing the colored lights previously correlated with either the small or large FR components. Existing pause differentials were not disrupted under the light reversal or random conditions.

In Experiment II, the same rabbits were stabilized at mult FR 10 FR 30 with ½ cc of water delivered after each component. In subsequent conditions the magnitude of reinforcement (cc's of water) delivered at the completion of the large FR component, was systematically shifted from 4 cc, to 3 cc, 2 cc, 1 cc and finally back to ½ cc. Pausing before the large FR was found to be inversely related to the magnitude of reinforcement delivered in that component.

Clearly the animals in this experiment discriminated upcoming schedule conditions and paused relative to FR size and reinforcement magnitude. Hence, it is proper to point out that the term "post-reinforcement pause" is a misnomer since it incorrectly implies a functional relation between pause length and prior schedule conditions.



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