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Geoffrey Hall

Bio: Geoffrey Hall is an academic researcher from University of York. The author has contributed to research in topics: Classical conditioning & Latent inhibition. The author has an hindex of 48, co-authored 221 publications receiving 9994 citations. Previous affiliations of Geoffrey Hall include University of New South Wales & University of Plymouth.


Papers
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Journal ArticleDOI
TL;DR: A new model is proposed that deals with the explanation of cases in which learning does not occur in spite of the fact that the conditioned stimulus is a signal for the reinforcer by specifying that certain procedures cause a conditioned stimulus to lose effectiveness.
Abstract: Several formal models of excitatory classical conditioning are reviewed. It is suggested that a central problem for all of them is the explanation of cases in which learning does not occur in spite of the fact that the conditioned stimulus is a signal for the reinforcer. We propose a new model that deals with this problem by specifying that certain procedures cause a conditioned stimulus (CS) to lose effectiveness; in particular, we argue that a CS will lose associability when its consequences are accurately predicted. In contrast to other current models, the effectiveness of the reinforcer remains constant throughout conditioning. The second part of the article presents a reformulation of the nature of the learning produced by inhibitory-conditioning procedures and a discussion of the way in which such learning can be accommodated within the model outlined for excitatory learning.

2,779 citations

Book
01 Jan 1991
TL;DR: Associative theory and the phenomena of perceptual learning Habituation Latent inhibition as reduced associability Latent inhibited as associative interference Acquired distinctiveness: mediation and differentiation Acquired separateiveness: attentional factors Discrimination after stimulus exposure Learning and the modification of stimulus representations.
Abstract: Associative theory and the phenomena of perceptual learning Habituation Latent inhibition as reduced associability Latent inhibition as associative interference Acquired distinctiveness: mediation and differentiation Acquired distinctiveness: attentional factors Discrimination after stimulus exposure Learning and the modification of stimulus representations References Indexes.

437 citations

Journal ArticleDOI
TL;DR: Four experiments to investigate the transfer of learning from one context to another showed that the habituation of the unconditioned response to a stimulus presented in one context was left intact when the stimulus was presented in another context, but that latent inhibition was attenuated when preexposure and conditioning phases occurred in different contexts.
Abstract: Rats were used as subjects in four experiments to investigate the transfer of learning from one context to another. Subjects received two sessions of training each day, one in each of two different contexts. Experiment 1 showed that the habituation of the unconditioned response to a stimulus presented in one context was left intact when the stimulus was presented in another context, but that latent inhibition was attenuated when preexposure and conditioning phases occurred in different contexts. Experiments 2 and 3 demonstrated that a conditioned response made on the basis of an appetitive reinforcer was diminished when conditioning and testing occurred in different contexts, but that aversive conditioning was not influenced by the context in which testing occurred. In Experiment 4, the presence of an aversive reinforcer during training did not preclude the occurrence of context-specific conditioning on the basis of an appetitive reinforcer. Associative and retrieval-based interpretations of the results are explored.

242 citations

Journal ArticleDOI
TL;DR: Results suggest that the basolateral amygdala is involved in the representation of the sensory aspects of motivationally significant events in Pavlovian-to-instrumental transfer and reinforcer specificity of that enhancement.
Abstract: The amygdala is known to play a role in learning about motivationally significant events. We investigated this role further by examining the effects of excitotoxic lesions of the basolateral amygdala on the ability of rats to use instrumental outcomes to direct responding (the differential outcomes effect) and on the ability of Pavlovian cues to modulate instrumental performance based on shared outcomes (reinforcer–selective Pavlovian-to-instrumental transfer). We found that basolateral amygdala (BLA) lesions did not affect the ability of rats to learn a basic instrumental conditional discrimination, but did disrupt the ability of differential outcomes to facilitate acquisition. In Pavlovian-to-instrumental transfer, BLA lesions did not disrupt the basic enhancement of instrumental performance but did abolish the reinforcer specificity of that enhancement. These results suggest that the BLA is involved in the representation of the sensory aspects of motivationally significant events.

226 citations

Journal ArticleDOI
TL;DR: The extent to which stimuli are treated as being equivalent is partly determined by their reinforcement histories, as indicated by the results of Experiments 1 and 2.
Abstract: In Experiments 1 and 2, rats received initial training in which two stimuli (A and N) were either followed by the same consequence (food) or by different consequences (food and no food). Subsequently N was paired with electric shock and the generalization of conditioned suppression to A was assessed. Suppression to A was more marked when A and N had both been followed by food than when they had had different outcomes. In Experiment 3, 3 stimuli (A, B, and N) were presented initially. For one group, A and N were paired with food and B was nonreinforced; for a second group, B was paired with food and A and N were nonreinforced. Generalization of suppression was found to be more substantial to A than to B for both groups. These results indicate that the extent to which stimuli are treated as being equivalent is partly determined by their reinforcement histories. The observation that a conditioned response that has been established to one stimulus will also be elicited, to some extent, by other stimuli is known as stimulus generalization. A widely held interpretation of this phenomenon relies on the assumption that the presentation of a stimulus will unconditionally excite a number of representational elements. It is supposed that though some of these elements (unique elements) will be activated only by the trained stimulus itself, others (common elements) will be activated by a range of stimuli (see, e.g., Atkinson & Estes, 1963; Mackintosh, 1974; Rescorla, 1976). To the extent that two stimuli excite common elements, animals will perceive them as alike and will respond to them in similar ways. This analysis provides a ready explanation of stimulus generalization and of a range of other phenomena (Rescorla, 1976).

207 citations


Cited by
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Journal ArticleDOI
TL;DR: Dopamine systems may have two functions, the phasic transmission of reward information and the tonic enabling of postsynaptic neurons.
Abstract: Schultz, Wolfram. Predictive reward signal of dopamine neurons. J. Neurophysiol. 80: 1–27, 1998. The effects of lesions, receptor blocking, electrical self-stimulation, and drugs of abuse suggest t...

3,962 citations

Journal ArticleDOI
TL;DR: This target article critically examines this "hierarchical prediction machine" approach, concluding that it offers the best clue yet to the shape of a unified science of mind and action.
Abstract: Brains, it has recently been argued, are essentially prediction machines. They are bundles of cells that support perception and action by constantly attempting to match incoming sensory inputs with top-down expectations or predictions. This is achieved using a hierarchical generative model that aims to minimize prediction error within a bidirectional cascade of cortical processing. Such accounts offer a unifying model of perception and action, illuminate the functional role of attention, and may neatly capture the special contribution of cortical processing to adaptive success. This target article critically examines this "hierarchical prediction machine" approach, concluding that it offers the best clue yet to the shape of a unified science of mind and action. Sections 1 and 2 lay out the key elements and implications of the approach. Section 3 explores a variety of pitfalls and challenges, spanning the evidential, the methodological, and the more properly conceptual. The paper ends (sections 4 and 5) by asking how such approaches might impact our more general vision of mind, experience, and agency.

3,640 citations

Journal ArticleDOI
TL;DR: A new model is proposed that deals with the explanation of cases in which learning does not occur in spite of the fact that the conditioned stimulus is a signal for the reinforcer by specifying that certain procedures cause a conditioned stimulus to lose effectiveness.
Abstract: Several formal models of excitatory classical conditioning are reviewed. It is suggested that a central problem for all of them is the explanation of cases in which learning does not occur in spite of the fact that the conditioned stimulus is a signal for the reinforcer. We propose a new model that deals with this problem by specifying that certain procedures cause a conditioned stimulus (CS) to lose effectiveness; in particular, we argue that a CS will lose associability when its consequences are accurately predicted. In contrast to other current models, the effectiveness of the reinforcer remains constant throughout conditioning. The second part of the article presents a reformulation of the nature of the learning produced by inhibitory-conditioning procedures and a discussion of the way in which such learning can be accommodated within the model outlined for excitatory learning.

2,779 citations

Journal ArticleDOI
TL;DR: A new framework for a more adequate theoretical treatment of perception and action planning is proposed, in which perceptual contents and action plans are coded in a common representational medium by feature codes with distal reference, showing that the main assumptions are well supported by the data.
Abstract: Traditional approaches to human information processing tend to deal with perception and action planning in isolation, so that an adequate account of the perception-action interface is still missing On the perceptual side, the dominant cognitive view largely underestimates, and thus fails to account for, the impact of action-related processes on both the processing of perceptual information and on perceptual learning On the action side, most approaches conceive of action planning as a mere continuation of stimulus processing, thus failing to account for the goal-directedness of even the simplest reaction in an experimental task We propose a new framework for a more adequate theoretical treatment of perception and action planning, in which perceptual contents and action plans are coded in a common representational medium by feature codes with distal reference Perceived events (perceptions) and to-be-produced events (actions) are equally represented by integrated, task-tuned networks of feature codes – cognitive structures we call event codes We give an overview of evidence from a wide variety of empirical domains, such as spatial stimulus-response compatibility, sensorimotor synchronization, and ideomotor action, showing that our main assumptions are well supported by the data

2,736 citations