UVM Theses and Dissertations
Format:
Print
Author:
Trask, Sydney M.
Dept./Program:
Psychology
Year:
2014
Degree:
M.A.
Abstract:
Two experiments were designed to test the possible role of a Context -R or a Context-(R-O) association in instrumental learning as proposed by Bouton, Todd, and Leon (2014). Rat subjects were given training sessions in Context A, in which responses on one manipulandum (Rl) led to one outcome (O1) and responses on another manipulandum (R2) led to another outcome (O2) on variable interval reinforcement schedules. These sessions were intennixedwith training in Context B, where Rl now led to O2 and R2 led to O1. Given the arrangement, it was possible for each animal to learn two distinct R -O associations in each specific context. To test for them, following instrumental training, animals were given aversion conditioning with O2 by pairing its presentation with illness. Following the aversion conditioning, the animals were then given an extinction test with both Rl and R2 available in each context, followed by a reacquisition test.
In Experiment 1, during the extinction and reacquisition tests, animals showed a selective suppression in each context of the response that had been paired with the reinforcer that was subsequently associated with illness, although suppression was not complete. An incomplete aversion to the O2 pellet complicated interpretation of this result and prompted methodological changes in Experiment 2 aimed to increase the ability of the aversion to transfer to the test situation.
In Experiment 2, where animals showed a more complete aversion to the devalued pellet, they again showed a selective suppression in each context of the response that had been paired with the reinforcer subsequently associated with illness. Animals could not have shown R1>R2 in Context A and the opposite (R2>R1) in Context B without knowledge of the R -O associations in effect in each specific context, lending support to the hypothesis that animals learn Context -(R -O) associations. However, despite the complete aversion, response suppression was not total, leaving the possibility open that animals fonn Context -R associations in addition to Context -(R -O) associations.
In Experiment 1, during the extinction and reacquisition tests, animals showed a selective suppression in each context of the response that had been paired with the reinforcer that was subsequently associated with illness, although suppression was not complete. An incomplete aversion to the O2 pellet complicated interpretation of this result and prompted methodological changes in Experiment 2 aimed to increase the ability of the aversion to transfer to the test situation.
In Experiment 2, where animals showed a more complete aversion to the devalued pellet, they again showed a selective suppression in each context of the response that had been paired with the reinforcer subsequently associated with illness. Animals could not have shown R1>R2 in Context A and the opposite (R2>R1) in Context B without knowledge of the R -O associations in effect in each specific context, lending support to the hypothesis that animals learn Context -(R -O) associations. However, despite the complete aversion, response suppression was not total, leaving the possibility open that animals fonn Context -R associations in addition to Context -(R -O) associations.