Master's Theses



Degree Name

Master of Science (MS)


Several articles have appeared in the recent psychological literature which point out some hazards in positively reinforcing a response with a baseline frequency greater than zero. These studies provide data which indicate that, following external reinforcement of such behavior, its frequency fell to below baseline rates when reinforcement was terminated. This study attempted to point out some methodological errors in previous research and carried out a controlled replication of the basic paradigm. Wheel running in three groups of gerbils was studied. Group 1 was a non-reinforced group used to control for changes in wheel running in the experimental chamber due to handling and temporal factors. Group 2 received a 15% sucrose solution for wheel running in the experimental chamber. Group 3 was exposed to the same contingencies as Group 2. However, these subjects also had continuous access to an activity wheel in their home cages. Data from Group 3 indicated that reinforcement does not appear to reduce what some researchers have labeled as intrinsic motivation to respond. What may be suppressed, however, is the frequency of the operant outside the experimental situation. It is postulated that this phenomenon may be similar to behavioral contrast found in multiple schedules. Data from the other two groups was obscured by enough inter-subject variability so as to make interpretation of the results tenuous. It was recommended that future research control for the hypothesized sources of error (light, temperature, etc.) and that food or water deprived subjects be used.


Robert Adams

Date of Award

Spring 1975

Document Type

Thesis - campus only access


© 1975 Maurice Shellhaas


For questions contact

Off Campus FHSU Users Click Here