Mechanisms Underlying the Accuracy of Stimulus Representations: Within-event Learning and Outcome Mediation

Lagator, Sandra and Muñiz-Diez, Clara and Beesley, Tom and Haselgrove, Mark (2025) Mechanisms Underlying the Accuracy of Stimulus Representations: Within-event Learning and Outcome Mediation. Journal of Experimental Psychology: Animal Learning and Cognition. ISSN 2329-8456 (In Press)

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Abstract

Valid predictors of an outcome attract more attention than stimuli which are non-predictive. Furthermore, stimuli which have a probabilistic association with an outcome attract more attention than stimuli which 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 non-predictive 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. Test trials revealed more accurate recognition for which predictive stimuli were paired together relative to non-predictive 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 non-predictive 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 discussed in the context of attentional theories of associative learning.