Contextual control of instrumental actions and habits

Abstract

After a relatively small amount of training, instrumental behavior is thought to be an action under the control of the motivational status of its goal or reinforcer. After more extended training, behavior can become habitual and insensitive to changes in reinforcer value. Recently, instrumental responding has been shown to weaken when tested outside of the training context. The present experiments compared the sensitivity of instrumental responding in rats with a context switch after training procedures that might differentially generate actions or habits. In Experiment 1, lever pressing was decremented in a new context after either short, medium, or long periods of training on either random-ratio or yoked random-interval reinforcement schedules. Experiment 2 found that more minimally trained responding was also sensitive to a context switch. Moreover, Experiment 3 showed that when the goal-directed component of responding was removed by devaluing the reinforcer, the residual responding that remained was still sensitive to the change of context. Goal-directed responding, in contrast, transferred across contexts. Experiment 4 then found that after extensive training, a habit that was insensitive to reinforcer devaluation was still decremented by a context switch. Overall, the results suggest that a context switch primarily influences instrumental habit rather than action. In addition, even a response that has received relatively minimal training may have a habit component that is insensitive to reinforcer devaluation but sensitive to the effects of a context switch.

Figure 1

Results of Experiment 1. Mean response rates of the groups during acquisition in Context A. RR is Random Ratio, RI is Random interval, 1260, 540, 300 are total number of reinforced lever presses in training (including CRF and RR 5 sessions).

Figure 2

Results of Experiment 1. Mean response rates during the extinction test in Contexts A and B plotted as a function of total number of reinforced responses in training. Error bars represent SEM. Error bars are included for comparison of between-group differences, and are not relevant for interpreting within-subject differences (i.e., the context effect).

Figure 3

Results of Experiment 2. Mean response rates for each group in Contexts A and B. Error bars represent SEM. Error bars are included for comparison of between-group differences, and are not relevant for interpreting within-subject differences (i.e., the context effect).

Figure 4

Results of Experiment 3. Mean response rates for each group in Contexts A and B. Error bars represent SEM. Error bars are included for comparison of between-group differences, and are not relevant for interpreting within-subject differences (i.e., the context effect).

Figure 5

Results from Experiment 3. Mean magazine entry rates during the pellet consumption test in Contexts A and B. Error bars represent SEM. Error bars are included for comparison of between-group differences, and are not relevant for interpreting within-subject differences (i.e., the context effect).

Figure 6

Results from Experiment 3. Mean response rates or the groups plotted as a function of 5-min bin in the reacquisition test session. Error bars represent SEM.

Figure 7

Results of Experiment 4. Mean response rates for each group in Contexts A and B during the testing sessions. P is Paired, U is Unpaired, 360 and 90 refer to total number of reinforced lever presses in training. Error bars represent SEM. Error bars are included for comparison of between-group differences, and are not relevant for interpreting within-subject differences (i.e., the context effect).

Figure 8

Results from Experiment 4. Mean number of pellets consumed (top panel) and mean magazine entry rates (Bottom) for the groups in the consumption test. P is Paired, U is Unpaired, 360 and 90 refer to total number of reinforced lever presses in training. Error bars represent SEM. Error bars are included for comparison of between-group differences, and are not relevant for interpreting within-subject differences (i.e., the context effect).

Figure 9

Results from Experiment 4. Mean response rates for each group plotted as a function of 5-min bin in the reacquisition test. P is Paired, U is Unpaired, 360 and 90 refer to total number of reinforced lever presses in training. Error bars represent SEM.