Award details

Stimulus relevance in discrimination learning

Reference	BB/C512888/1
Principal Investigator / Supervisor	Professor John Martindale Pearce
Co-Investigators / Co-Supervisors	Dr David George, Dr Mark Haselgrove, Dr Jasper Robinson
Institution	Cardiff University
Department	Sch of Psychology
Funding type	Research
Value (£)	224,070
Status	Completed
Type	Research Grant
Start date	01/05/2005
End date	31/01/2009
Duration	45 months

Abstract

Studies of learning in animals and humans have shown that a stimulus which is irrelevant to the solution of a discrimination will gain less control over behaviour than one that is relevant, even though they may both share the same relationship with reward. Although this relative validity effect is well established, rather little research has been directed at understanding the mechanisms that are responsible for it. Such a lack of research is surprising because every discrimination involves irrelevant stimuli and an analysis of how they are treated is fundamental to our understanding of the basic mechanisms of discrimination learning. Experiments will evaluate, therefore, different theoretical explanations for the relative validity effect. One set of experiments will explore the possibility that this effect is a consequence of more attention being paid to relevant than irrelevant stimuli. If this is correct, then animals should learn more readily in a new task about stimuli that were relevant rather than irrelevant discrimination. Another set of experiments will test the claim for comparator theories that animals respond weakly to a stimulus that is irrelevant to a discrimination because it is accompanied by stimuli that are better predictors of reward than itself. If this is correct, the ratio of reinforced to nonreinforced trials of the discrimination will influence the control acquired by an irrelevant stimulus. Experiments testing this prediction will also be of value for evaluating the most influential theory of discrimination learning that proposed by Rescoria and Wagner (1972). In contrast to comparator theory, this theory predicts that the manipulation just mentioned will not alter the associative properties of the irrelevant stimulus. Finally experiments will explore the role that configural information plays in the solution of relatively simple discriminations that contain irrelevant stimuli. According to configural theories of discrimination learning, oncesuch a discrimination has been mastered, reversing the significance of the relevant stimuli, will weaken but not reverse the effects of the training with the original patterns. Overall, the experiments are expected to reveal that a variety of factors are responsible for the relative validity effect. The experiments will use standard appetitive Pavlovian conditioning techniques. Rats will receive combinations of auditory and visual stimuli as the patterns used for signalling the presence and absence of reward; pigeons will receive combinations of visual stimuli. The use of two species is important for demonstrating the generality of the findings from the research.

Summary

unavailable

Committee	Closed Committee - Animal Sciences (AS)
Research Topics	Neuroscience and Behaviour
Research Priority	X – Research Priority information not available
Research Initiative	X - not in an Initiative
Funding Scheme	X – not Funded via a specific Funding Scheme

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