Date of Award
Master of Arts in Psychology
An experiment was performed to determine the relative efficacy of "predictive information value" and of temporal contiguity with a primary reinforcer (SR) in establishing conditioned reinforcement value of previously neutral stimuli. Three different temporal patterns of pairs of neutral stimuli were presented both contiguously with non-response contingent primary reinforcement (experimental groups) and non-contiguously with primary reinforcement. Subsequently, the efficacy of these stimuli in reinforcing a new response (lever press) was assessed, both across pairs of stimuli and within each pair. Previous findings regarding the optimal temporal intervals between stimuli and between stimuli and reinforcement for maximum information value and maximum contiguity were utilized to allow discrimination between the predictions of the two models.
Forty-eight Sprague-Dawley adult male rats were trained with 210 non-contingent presentations of the neutral stimuli and the SR over a period of five days. For half of the subjects, the stimuli and SR were presented contiguously. The other half received the stimuli at random. Relative to presentation of the SR, using a random control procedure. Subjects were tested over a three day period in a two lever operant chamber with the neutral stimuli available on separate levers contingent upon the lever press response. Daily testing trials lasted 30 minutes with each daily session being recorded in consecutive 5 minute segments.
The results were analyzed using two four-way ANOVA's with repeated measures across two factors, the first being number of responses across successive days of testing and the second number of responses
across successive 5 minute segments of Day 1. In the first ANOVA, a significant main effect was indicated across daily testing sessions. A follow-up test indicated that responding occurred primarily during Day 1, with negligible responding during Days 2 and 3. No other significant main effects or interaction effects were found in the first analysis.
In the second ANOVA, a significant main effect was found for consecutive 5-minute testing segments, as well as a significant interaction between the experimental/control factor and the repeated measures S1/S2 factor. Follow-up tests indicated that greater responding occurred during the first two 5-minute segments and that control subjects responded more to the first stimulus than did experimental subjects. Further, experimental subjects in one stimulus pair showed a preference for S2, while controls showed a preference for S1 These results occurred, however, in the stimulus pair predicted to have the least optimal temporal arrangement for the establishment of a conditioned reinforcement effect.
Overall, the results did not provide adequate support for either a contiguity or information model. Possible problems of insensitivity in the procedure with this traditionally weak phenomenon are discussed as well as the possibility that the true conditioned reinforcer may have been the pattern of bath stimuli which was not presented in testing. Further research possibilities are discussed
Harris, Robert Stephen, "The Establishment of Conditioned Reinforcement in Rats: Information Value or Contiguity" (1981). Open Access Master's Theses. Paper 1613.