Overshadowing and CS duration: counteraction and a reexamination of the role of within-compound associations in cue competition

Abstract

In the present experiments, we examined the role of within-compound associations in the interaction of the overshadowing procedure with conditioned stimulus (CS) duration, using a conditioned suppression procedure with rats. In Experiment 1, we found that, with elemental reinforced training, conditioned suppression to the target stimulus decreased as CS duration increased (i.e., the CS duration effect), whereas, with compound reinforced training (i.e., the overshadowing procedure), conditioned suppression to the target stimulus increased as CS duration increased. In subsequent experiments, we replicated these findings with sensory preconditioning and demonstrated that extinction of the overshadowing stimulus results in retrospective revaluation with short CSs and in mediated extinction with long CSs. These results highlight the role of the duration of the stimulus in behavioral control. Moreover, these results illuminate one cause (the CS duration) of whether retrospective revaluation or mediated extinction will be observed.

Figure 1

Results of Experiment 1. Mean log latencies to complete the first five cumulative seconds of drinking in the presence of the target cue (X). Error bars represent the standard error of the means. See text for details.

Figure 2

Results of Experiment 2. Mean log latencies to complete the first five cumulative seconds of drinking in the presence of the target cue (X). All subjects were trained with the AX compound. Error bars represent the standard error of the means. See text for details.

Figure 3

Results of Experiment 3. Mean log latencies to complete the first five cumulative seconds of drinking in the presence of the target cue (X). Error bars represent the standard error of the means. See text for details.

Figure 4

Results of Experiment 4. Mean log latencies to complete the first five cumulative seconds of drinking in the presence of the target cue (X). All subjects were trained with the AX compound. Error bars represent the standard error of the means. See text for details.

Figure 5

Diagram of the ECH with A as the first-order comparator stimulus and context as the second-order comparator stimulus. Ctx = context. Rectangles indicate test stimulus and response; ovals indicate mental representations; diamonds indicate comparator mechanism.