Effect of Context on the Instrumental Reinforcer Devaluation Effect Produced by Taste-Aversion Learning

Four experiments manipulated the context in which taste-aversion conditioning occurred when the reinforcer was devalued after instrumental learning. In all experiments, rats learned to lever press in an operant conditioning chamber and then had an aversion to the food-pellet reinforcer conditioned by pairing it with lithium chloride (LiCl) in either that context or a different context. Lever pressing was then tested in extinction to assess its status as a goal-directed action. In Experiment 1, aversion conditioning in the operant conditioning chamber suppressed lever-pressing during the test, but aversion conditioning in the home cage did not. Exposure to the averted pellet in the operant conditioning chamber after conditioning in the home cage did not change this effect (Experiment 2). The same pattern was observed when the different context was a second operant-style chamber (counterbalanced), exposure to the contexts was controlled, and pellets were presented in them in the same manner (Experiment 3). The greater effect of aversion conditioning in the instrumental context was not merely due to potentiated contextual conditioning (Experiment 4). Importantly, consumption tests revealed that the aversion conditioned in the different context had transferred to the test context. Thus, when reinforcer devaluation occurred in a different context, the rats lever pressed in extinction for a reinforcer they would otherwise reject. The results suggest that animals encode contextual information about the reinforcer during instrumental learning and suggest caution in making inferences about action versus habit learning when the reinforcer is devalued in a different context.