Mechanisms underlying the accuracy of stimulus representations: Within-event learning and outcome mediation.

Abstract

Valid predictors of an outcome attract more attention than stimuli that are nonpredictive. Furthermore, stimuli that have a probabilistic association with an outcome attract more attention than stimuli that have a deterministic association with an outcome. Two experiments investigated whether predictive validity and outcome uncertainty resulted in the establishment of a more accurate stimulus representation, in which accuracy was measured as the strength of associations between different elements of a compound stimulus. In Experiment 1, pairs of stimuli were established as outcome predictive (always followed by the same outcome) and presented in conjunction with nonpredictive pairs of stimuli (equally likely to be followed by two different outcomes). Outcome uncertainty was also manipulated, between groups, by establishing either a deterministic (100%) or probabilistic (80%) contingency between the predictive pairs and their outcomes. The test trials revealed more accurate recognition for which predictive stimuli were paired together relative to nonpredictive stimuli; however, there was no effect of outcome uncertainty. Experiment 2 reproduced the effect observed in the deterministic group from Experiment 1 and also demonstrated that the superior performance to the predictive stimuli over the nonpredictive stimuli was only evident when, at test, the choice stimuli had predicted different outcomes during training. These results were interpreted as the consequence of two pathways to accurate stimulus representation: direct (within-compound associations) and indirect (mediated through the activation of the outcome) and are discussed in the context of attentional theories of associative learning. (PsycInfo Database Record (c) 2025 APA, all rights reserved).