An inhibitory within-compound association attenuates overshadowing.

Abstract

According to the comparator hypothesis (Miller & Matzel, 1988), cue competition depends on the association between a target stimulus (X) and a competing cue (e.g., an overshadowing cue [A]). Thus, it was expected that overshadowing would be reduced by establishing an inhibitory-like relationship between X and A before compound conditioning. In three lever press suppression experiments with rats, this expectation was supported. Experiment 1 showed that establishing an inhibitory X-A relationship reduced overshadowing. In Experiment 2, degrading the inhibitory-like relationship before conditioning allowed reinforced AX compound trials to result in overshadowing. Experiment 3 replicated the results of Experiment 2 when the inhibitory relationship was degraded after compound conditioning. The results support the view that within-compound associations are necessary not only for retrospective revaluation, but also for conventional cue competition.

The error in total error reduction

“…Table 11 reproduces the best fitting predictions and group means of Amundson et al’s (2008) Experiment 1 and Table 3 summarizes the fit of the models to Amundson et al’s results. Notably, while Tables 10 and 11 summarize only data pertaining to Experiment 1, the predictions, SSE, and BIC scores are based on applying the models to both Experiments 1 and 2.…”

“…In contrast to the simple response rule used by the TER models simulated here (i.e., Rx = Vx-US), SOCR, which is a model based on a nontrivial performance rule and noncompetitive (i.e., LER) acquisition rule, explained all of the results that were problematic for the TER approach. Moreover, among the TER models, the Hybrid model performed better in terms of uncontrolled fit (SSE) than the other TER models as applied to Rescorla’s (2000, see Simulation 2) and Amundson et al’s (2008, see Simulation 4a) results, presumably because, similar to SOCR, it assumes a critical role for within-compound associations in cue interactions in general rather than uniquely during retrospective revaluation. Notably, simple TER models that did not use within-compound associations to explain cue interactions (the backpropagation and the Rescorla and Wagner models), failed to explain any of the experiments simulated in the present paper.…”

“…In addition to using information provided by the direct X-US and A-US associations, animals might access the US representation and respond based, at least in part, on the X-A or A-X associations. This possibility has gained considerable theoretical (Dickinson & Burke, 1996; Miller & Matzel, 1988; Pineno, 2007; Van Hamme & Wasserman, 1994) and empirical (Amundson, Witnauer, Pineno, & Miller, 2008) attention. The TER models simulated in the present research differ in important and systematic ways from each other and from SOCR with respect to the emphasis placed on within-compound associations.…”

“…Unfortunately, the serial compound trials preclude simulation because the models described here are trial-wise (instead of real time). Amundson et al (2008) sought to further study the role of within-compound associations by directly manipulating within-compound associations and measuring the effect of doing so on cue competition. Specifically, Amundson et al conducted the experiment summarized in Table 10.…”

Revisiting the role of within-compound associations in cue-interaction phenomena

“…Experiments that have assessed the role of within-compound associations in forward cue-interaction phenomena have been aimed at investigating whether, as the comparator hypothesis predicts, within-compound associations play the same roles in forward cue interaction and in retrospective revaluation (Stout & Miller, 2007). The results of several causal learning experiments that have been conducted using human participants appear to refute this prediction (Aitken et al, 2001;Dickinson & Burke, 1996;Melchers et al, 2004Melchers et al, , 2006, but a study by Amundson, Witnauer, Pineño, and Miller (2008) showed that within-compound associations could mediate overshadowing in three different conditioning experiments that utilized rats. Although there are some cases in which an overshadowing condition can be used as a control condition for other types of cue-interaction effects, such as Experiment 1 of this study, overshadowing itself can be considered a cueinteraction phenomenon, because cues that are presented together compete with each other.…”