Effect of context on the instrumental reinforcer devaluation effect produced by taste-aversion learning.

Abstract

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.

Reinforcer predictability and stimulus salience promote discriminated habit learning.

“…Similar results were found in experiments that arranged the unexpected reinforcers to be contingent or not contingent on a second response (Trask et al, 2020). As noted by Bouton and colleagues (Bouton et al, 2020; Trask et al, 2020); the results are consistent with the idea that an unpredicted, or surprising, outcome results in an increase in attention to the response in a manner similar to the increase in CS processing envisaged by Pearce and Hall (1980). In the free operant studies, surprise allowed rats to switch from habit back to action, whereas in the present studies it prevented habit from developing under PRF.…”

“…In PRF conditions, the reinforcer during any S becomes less predictable and more surprising, thus maintaining attention to both the stimulus and the response. Other recent free-operant studies from this laboratory have produced results that can be viewed from this perspective (Bouton et al, 2020; Trask et al, 2020). Bouton et al (2020) trained rats on schedules of reinforcement that typically result in habit (Dickinson et al, 1995; Thrailkill & Bouton, 2015).…”

“…Other recent free-operant studies from this laboratory have produced results that can be viewed from this perspective (Bouton et al, 2020; Trask et al, 2020). Bouton et al (2020) trained rats on schedules of reinforcement that typically result in habit (Dickinson et al, 1995; Thrailkill & Bouton, 2015). Prior to a test for sensitivity to reinforcer devaluation, half the rats received exposure to a different reinforcer.…”

“…The finding that PRF sustains goal-directed control, while CRF does not, may be difficult to reconcile with a rate correlation view. A fourth problem for at least one version of correlation theory (Perez & Dickinson, 2020) is other evidence suggesting that the acquisition of an S–R habit does not appear to erase or destroy previously-acquired action (R–O) knowledge (e.g., Bouton et al, 2020; Steinfeld & Bouton, 2020; Trask et al, 2020).…”

Model based control can give rise to devaluation insensitive choice

“…(c) In some circumstances, instrumental responding persists despite reinforcer devaluation (stylized data illustrated), a behavior which is viewed as arising from a reliance on habits (model free learning). This occurs, for example, when animals are overtrained (Holland, 2004) as well as when the context in which the aversion conditioning occurs differs to that used for the acquisition and test phases (Bouton et al, 2021).…”