R. Honey - Academia.edu (original) (raw)

Papers by R. Honey

Research paper thumbnail of Lesions of the mammillothalamic tract impair the acquisition of spatial but not nonspatial contextual conditional discriminations

European Journal of Neuroscience, 2003

This study examined the in¯uence of selective mammillothalamic tract lesions in rats on the acqui... more This study examined the in¯uence of selective mammillothalamic tract lesions in rats on the acquisition of two kinds of contextual conditional discrimination: one involving two contexts (A and B) that differed in their visuo-spatial properties and another involving two contexts (C and D) that differed in temperature. In contexts A (and C) presentations of a tone were paired with food whereas presentations of a clicker were not; and in contexts B (and D) presentations of the clicker were paired with food whereas those of the tone were not. Mammillothalamic tract lesions disrupted initial acquisition of the conditional discrimination involving visual contexts (A and B), but not the formally equivalent discrimination involving thermal contexts (C and D). These results provide support for the suggestion that mammillothalamic tract lesions disrupt visuo-spatial encoding.

Research paper thumbnail of Perceptual learning with tactile stimuli in rats: Changes in the processing of a dimension

Journal of experimental psychology. Animal learning and cognition, 2016

Four experiments with male rats investigated perceptual learning involving a tactile dimension (A... more Four experiments with male rats investigated perceptual learning involving a tactile dimension (A, B, C, D, E), where A denotes 1 end of the continuum (e.g., a rough floor) and E the other (e.g., a smooth floor). In Experiment 1, rats given preexposure to A and E learned an appetitive discrimination between them more readily than those not given preexposure. Experiment 2a showed that rats preexposed to B and D acquired a discrimination between A and E more readily than those preexposed to A and E; and in Experiment 2b the same preexposure treatments had no effect on the acquisition of a discrimination between B and D. In Experiments 3a and 3b, rats given preexposure to C learned a discrimination between A and E more readily than those not given preexposure. Experiment 4 demonstrated that preexposure to a texture (e.g., B) that was adjacent to the to-be-discriminated textures (e.g., C and E) facilitated a discrimination between them relative to preexposure to their midpoint (D). Thes...

Research paper thumbnail of Stimulus Comparison and Perceptual Learning: Further Evidence and Evaluation from an Imprinting Procedure

The Quarterly Journal of Experimental Psychology

Two experiments used chicks to investigate the role of stimulus comparison in perceptual learning... more Two experiments used chicks to investigate the role of stimulus comparison in perceptual learning. In Experiment 1, chicks received exposure to two views of a jungle fowl, SV (side view) and BV (back view), intermixed within a session (mixed exposure), exposure to SV in one session and BV in a different session (separate exposure), or no exposure to either view. All chicks then received a heat-reinforced discrimination with SV and BV serving as discriminanda. Chicks given mixed exposure acquired the discrimination more readily than did either those given separate exposure or those given no exposure. In Experiment 2, all chicks received mixed exposure to the two stimuli. For one group the interval between presentations of the stimuli was short (short-mixed), for the other group it was long (long-mixed). Subjects in the long-mixed condition acquired the heat-reinforced discrimination more rapidly than those in the short-mixed condition. These results suggest that the intermixed nature...

Research paper thumbnail of BRIEF COMMUNICATIONS Associative Change in Connectionist Networks: An Addendum

The results of a recent study have provided direct support for the suggestion that conditional le... more The results of a recent study have provided direct support for the suggestion that conditional learning in rats is best characterized by a 3-layer connectionist network (M. J. Allman, J. Ward-Robinson, & R. C. Honey, 2004). In the 2 experiments reported here, rats were used to investigate the nature of the changes that occur when a stimulus compound is presented, whose components activate hidden units associated with food and no food, and either food or no food is presented. The results of both experiments, while controlling for the possible contribution of associations between these hidden units (within-layer links), provide evidence that the distribution of associative change between units in the hidden layer that are activated by the stimulus compound and those in the output layer (between-layer links) are unequal. They also indicate that associative change is more marked on trials on which no food was presented than on trials on which food was presented.

Research paper thumbnail of Imprinting, learning and development: from behaviour to brain and back

Trends in Neurosciences, 1998

Neural and behavioural analyses have shown that the formation of filial preferences in young, pre... more Neural and behavioural analyses have shown that the formation of filial preferences in young, precocial birds involves at least two separate processes. One process is an emerging predisposition to approach stimuli with the characteristics of the natural mother. The other (learning) process of filial imprinting results in chicks preferentially-approaching a stimulus to which they have been exposed and involves forming links between the components of the exposed stimulus. The neural substrate for the predisposition is different from that underlying imprinting, and different regions of the chick brain are involved in distinct aspects of learning about imprinting stimuli.

Research paper thumbnail of Exploring the spatiotopic frame using motion after-effects

Research paper thumbnail of The role of similarity in human associative learning

Journal of Experimental Psychology: Animal Behavior Processes, 2007

In 2 experiments, humans received sequences of patterns that were similar (AX3 BX, AY3 BY, AZ3 BZ... more In 2 experiments, humans received sequences of patterns that were similar (AX3 BX, AY3 BY, AZ3 BZ) or dissimilar (CX3 DY, CY3 DZ, CZ3 DX). The patterns were portrayed as bugs that could be eliminated with 2 insecticide sprays (red or blue). Either spray eliminated bugs with Features A and C, and participants learned by trial and error to use one spray (e.g., red) to eliminate bugs with Feature B and the other spray (e.g., blue) to eliminate those with Feature D. In Experiment 1, participants' spray choice for bugs with Feature A came to match that used to eliminate bugs with Feature B, but there was no such associative transfer between Features C and D. That is, similarity promoted associative transfer of responding between paired patterns when the features used to manipulate similarity (i.e., X, Y, and Z) were irrelevant. In Experiment 2, in which X, Y, and Z were relevant to the solution of configural discrimination, similarity hindered such associative transfer. These results complement those found in pigeons (R. A. Rescorla & D. J. Gillan, 1980) and indicate that similarity should not be accorded independent status as a principle of associative learning.

Research paper thumbnail of Analysis of the content of configural representations: The role of associatively evoked and trace memories

Journal of Experimental Psychology: Animal Behavior Processes, 2010

Two experiments examined the content of configural learning in rats. In Experiment 1, after simpl... more Two experiments examined the content of configural learning in rats. In Experiment 1, after simple pre-exposure to two hybrid contexts (AB and CD), rats acquired a configural discrimination involving two of the contexts (A and C) and two auditory stimuli (X and Y; AX3food, AY3no food, CX3no food, and CY3food). When rats were then placed in context B, they were more likely to respond to X than Y, and when they were placed in context D the reverse was the case. Experiment 2 demonstrated that rats can acquire a configural discrimination involving the presence of context (A) and its memory trace (a; AX3food, AY3no food, aX3no food, and aY3food). These results show that associatively provoked memories (Experiment 1) and memory traces (Experiment 2) can participate in configural discriminations.

Research paper thumbnail of Stimulus generalization as a function of stimulus novelty and familiarity in rats

Journal of Experimental Psychology: Animal Behavior Processes, 1990

Threeexpefiments used rats as subjects to investigate the generalization of conditioned respondin... more Threeexpefiments used rats as subjects to investigate the generalization of conditioned responding between stimuli as a function of the subjects' exposure to these cues prior to conditioning. Experiment I used a between-subjects design, food as the reinforcer, and measured the tendency ofsubjects to approach the site of food delivery during the stimuli. Generalization of this response was more marked when the training and test stimuli were equated in terms of their novelty (i.e., when both were novel or both were familiar) than when the stimuli differed in this respect (i.e., when one was novel and the other was familiar). Experiments 2a and 2b used within-subjects designs to confirm the reliability of the results of Experiment 1. Implications of these results for current theories of stimulus representation are discussed.

Research paper thumbnail of Involvement of the rat medial prefrontal cortex in novelty detection

Behavioral Neuroscience, 2002

The prefrontal cortex in humans has been implicated in processes that underlie novelty detection ... more The prefrontal cortex in humans has been implicated in processes that underlie novelty detection and attention. This study examined the contribution of the rat medial prefrontal cortex to novelty detection using the targeting, or orienting, response (OR) as a behavioral index. Lesions to the medial prefrontal cortex (specifically the prelimbic and infralimbic cortices) influenced neither the OR to a novel visual stimulus from a localized light source (V1), nor the change in this OR over the course of a series of exposures to V1. However, after exposure to V1, the OR to a 2nd visual stimulus from the same source, V2, was more pronounced in control rats than in lesioned rats. These results suggest that the medial prefrontal cortex in the rat contributes to the process of novelty detection.

Research paper thumbnail of Loss of the thalamic nuclei for "head direction" impairs performance on spatial memory tasks in rats

Behavioral Neuroscience, 2001

This study sought to characterize the effects of removing the nuclei of primary importance in rel... more This study sought to characterize the effects of removing the nuclei of primary importance in relaying the thalamic head direction signal to the hippocampal formation (the anterior dorsal [AD] and lateral dorsal [LD] nuclei) on the performance of a variety of spatial and nonspatial tasks. The results indicate that combined excitotoxic lesions of the AD and LD nuclei produce marked deficits on a variety of spatial tasks. These tasks included T-maze alternation and the ability to locate a hidden platform set at a fixed distance and fixed direction from a beacon in a Morris water maze. Although object recognition appeared unaffected, marked impairments were found in the ability to detect when an object was placed in a novel position (object-in-place memory).

Research paper thumbnail of Asymmetry in the discrimination of quantity by rats: The role of the intertrial interval

Learning & behavior, 2016

In three experiments, rats were trained to discriminate between 20 and five (Exps. 1 and 2), or b... more In three experiments, rats were trained to discriminate between 20 and five (Exps. 1 and 2), or between 40 and five (Exp. 3), black squares. The squares were randomly distributed in the center of a white background and displayed on a computer screen. For one group, the patterns containing the higher quantity of squares signaled the delivery of sucrose (+), whilst patterns with the lower quantity of squares did not (-). For the second group, sucrose was signaled by the lower, but not by the higher, quantity of squares. In Experiment 1, the intertrial interval (ITI) was a white screen, and the 20+/5- discrimination was acquired more readily than the 5+/20- discrimination. For Experiment 2, the ITI was made up of 80 black squares on a white background. In this instance, the 5+/20- discrimination was acquired more successfully than the 20+/5- discrimination. In Experiment 3, two groups were trained with a 40+/5- discrimination, and two with a 5+/40- discrimination. For one group from ea...

Research paper thumbnail of Hippocampal Lesions Disrupt an Associative Mismatch Process

The Journal of Neuroscience, 1998

Novel assays were used to assess inter alia whether the hippocampus is involved in detecting nove... more Novel assays were used to assess inter alia whether the hippocampus is involved in detecting novelty per se or in an associative mismatch process. During training, rats received two audiovisual sequences (tone-left constant light and clickleft flashing light). In both sham-operated control rats and those with excitotoxic hippocampal lesions, novel visual targets provoked an orienting response that habituated during training. Moreover, like sham-operated rats, rats with hippocampal lesions acquired associations between the elements of two audiovisual sequences. However, subsequent test trials in which the auditory stimuli preceding the visual targets were switched (click-left constant light and tone-left flashing light) provoked renewed orienting to the visual targets in sham-operated rats but not in hippocampal rats. These results support the view that hippocampal damage results in a failure to detect (or act on) mismatches that are generated when an auditory stimulus associatively evokes the memory of one visual stimulus and a different (familiar) visual stimulus is present in the environment.

Research paper thumbnail of The origins of individual differences in how learning is expressed in rats: A general-process perspective

Journal of experimental psychology. Animal learning and cognition, Oct 1, 2016

Laboratory rats can exhibit marked, qualitative individual differences in the form of acquired be... more Laboratory rats can exhibit marked, qualitative individual differences in the form of acquired behaviors. For example, when exposed to a signal-reinforcer relationship some rats show marked and consistent changes in sign-tracking (interacting with the signal; e.g., a lever) and others show marked and consistent changes in goal-tracking (interacting with the location of the predicted reinforcer; e.g., the food well). Here, stable individual differences in rats' sign-tracking and goal-tracking emerged over the course of training, but these differences did not generalize across different signal-reinforcer relationships (Experiment 1). This selectivity suggests that individual differences in sign- and goal-tracking reflect differences in the value placed on individual reinforcers. Two findings provide direct support for this interpretation: the palatability of a reinforcer (as measured by an analysis of lick-cluster size) was positively correlated with goal-tracking (and negatively ...

Research paper thumbnail of Representational Blending in Human Conditional Learning: Implications for Associative Theory

The Quarterly Journal of Experimental Psychology Section B, 2003

In two experiments, participants were presented with pictures of different foods (A, B, C, D, X,)... more In two experiments, participants were presented with pictures of different foods (A, B, C, D, X,) and learned which combinations resulted in an allergic reaction in a fictitious patient, MrX. In Problem 1, when Aor B (but not Cor D) was combined with food Xan allergic reaction occurred, and when C or D(but not A or B) was combined with Y an allergic reaction occurred. In Experiment 1, participants also received Problem 2 in which A, B, C, and Dinteracted with foods V and Weither in the same way as X and Y, respectively, or in a different way. Participants performed more proficiently in the former than in the latter condition. In Experiment 2, after training on Problem 1, participants judged whether or not novel combinations of foods (e.g., AB, CD, AD, CB) would cause an allergic reaction in MrX. They were no more likely to indicate that ABor CD would cause an allergic reaction than AD or CB, but made their judgements more rapidly and with greater confidence on AB and CDtrials than o...

Research paper thumbnail of Configural Learning without Reinforcement: Integrated Memories for Correlates of What, Where, and When

Quarterly Journal of Experimental Psychology, 2008

In 2 experiments we examined the ability of rats to form configural memories of what auditory sti... more In 2 experiments we examined the ability of rats to form configural memories of what auditory stimulus (X or Y) was presented where (Context A or B) and when (morning or afternoon). In both experiments, rats received morning presentations of X in Context A and Y in Context B and afternoon presentations of X in B and Y in A. Subsequently, at midday the rats were exposed to trials where X was paired with footshock whereas Y was not. We then assessed the degree of contextual fear in A and B in the morning and the afternoon. In the morning, rats showed more fear in A than in B, and in the afternoon they showed more fear in B than in A. These results indicate that rats can form configural memories that represent what (X or Y) was presented, where (A or B), and when (morning or afternoon).

Research paper thumbnail of Revisiting places passed: Sensitization of exploratory activity in rats with hippocampal lesions

Quarterly Journal of Experimental Psychology, 2007

We examined the involvement of the hippocampus in short-term changes in exploratory behaviour in ... more We examined the involvement of the hippocampus in short-term changes in exploratory behaviour in an open field (Experiment 1) and experimental contexts (Experiment 2). In Experiment 1, rats with excitotoxic lesions of the hippocampus were more likely to revisit recently visited zones within the open field than were control rats. Similarly, in Experiment 2 rats with hippocampal lesions showed greater exploration of a context that they had recently explored than a context that they had less recently explored. This short-term sensitization effect was not evident in control rats. These findings are consistent with the suggestion that the recent presentation of a stimulus has two opposing effects on behaviour, sensitization, and habituation, and that hippocampal lesions disrupt the short-term process responsible for habituation, but not that responsible for sensitization.

Research paper thumbnail of A novel contextual dimension for use with an operant chamber: From simple to hierarchical forms of learning

Journal of Experimental Psychology: Animal Behavior Processes, 2000

A novel procedure is described in which the floor temperatures (warm and cool) in an operant cham... more A novel procedure is described in which the floor temperatures (warm and cool) in an operant chamber are used as contextual cues in 2 experiments with rats. Experiment 1 demonstrated that rats learn the relationship between these thermal contexts and auditory stimuli that have been paired with them. Experiment 2 showed that thermal contexts can serve a conditional function that (a) reflects the operation of a mechanism that is common to conventional, visual contexts and (b) is bound to these contexts' ability to retrieve the nature of the relationship between the auditory stimuli and food. The experimental study of rodent behavior within psychology and neuroscience has been dominated by the use of the operant chamber. Even in its basic form, this apparatus provides the opportunity to present animals with a range of stimuli, manipulanda, and events of motivational significance. Moreover, the ambient or contextual cues that accompany being placed in such a chamber (its visual characteristics, odor, and so on) are also cues that animals readily learn about (see Bouton, 1991). As versatile as this apparatus is, it remains the case that the number of stimulus dimensions that are both available and readily controlled (principally, the auditory and visual dimensions) serves as a constraint on the experiments that can be conducted. For example, when an additional stimulus dimension is required, different odor cues have been used that require procedures designed to minimize contamination between them. These procedures can be either expensive or inconvenient (e.g., Hall & Honey, 1989). At a practical level, therefore, the study of rodent behavior in the laboratory would be facilitated by the development of a system that allows another dimension to be presented. Moreover, many of our conceptual models of animal learning and memory (e.g., Gluck & Myers, 1993; McLaren, Kaye, & Mackintosh, 1989; Pearce, 1994; Rescoda & Wagner, 1972) assume that the principles that underlie them will be as likely to operate in one (sensory) domain as another. Use of an additional dimension would provide a way of assessing the generality of those effects on which our understanding of learning and memory has developed. With these practical and theoretical considerations in mind, we describe the development and use of a novel addition to an operant

Research paper thumbnail of Associative modulation of the orienting response: Distinct effects revealed by hippocampal lesions

Journal of Experimental Psychology: Animal Behavior Processes, 2000

The ability of auditory stimuli to modulate rats' tendency to orient to visual targets wa... more The ability of auditory stimuli to modulate rats' tendency to orient to visual targets was assessed. In Experiment 1, trials where an auditory stimulus (A) signaled one visual array (X) were intermixed with unsignaled presentations of a second array (Y). Comparison of the orienting responses (ORs) to X and Y revealed that A produced a transient (unconditioned) and an emerging (conditioned) disruptive influence on the OR to X. In Experiments 2 and 3, trials where A signaled X were intermixed with others where another auditory stimulus (B) signaled Y. Stimulus A's ability to modulate the OR to X was then assessed by presenting A prior to test arrays containing both X and Y. Control rats were more likely to orient to Y than X (Experiments 2 and 3) and rats with excitotoxic lesions of the hippocampus were more likely to orient to X than Y (Experiment 3). These results show that auditory stimuli exert distinct modulatory influences on the OR to visual stimuli with which they are associated.

Research paper thumbnail of Acquired relational equivalence: Implications for the nature of associative structures

Journal of Experimental Psychology: Animal Behavior Processes, 1998

In 2 experiments, rats received discrimination training in which separate presentations of A and ... more In 2 experiments, rats received discrimination training in which separate presentations of A and B signaled a common pair of relationships or associations (X-, food and Y-. no food), whereas presentations of C and D signaled a different pair of relationships (X ~ no food and Y-* food). To assess the nature of the associative structures acquired during this training, rats then received 2 types of revaluation procedure: In Experiment 1, A was paired with shock and C was not. In Experiment 2, the relationships that A and B had previously signaled (X-, food and Y-~ no food) were paired with shock, whereas those that C and D had signaled (Y ~ food and X ~ no food) were not. After both types of revaluation treatment, rats showed greater generalized conditioned suppression in the presence of B than D. These results indicate that A, B, C, and D come to evoke memories of the relationships or associations that they have signaled.

Research paper thumbnail of Lesions of the mammillothalamic tract impair the acquisition of spatial but not nonspatial contextual conditional discriminations

European Journal of Neuroscience, 2003

This study examined the in¯uence of selective mammillothalamic tract lesions in rats on the acqui... more This study examined the in¯uence of selective mammillothalamic tract lesions in rats on the acquisition of two kinds of contextual conditional discrimination: one involving two contexts (A and B) that differed in their visuo-spatial properties and another involving two contexts (C and D) that differed in temperature. In contexts A (and C) presentations of a tone were paired with food whereas presentations of a clicker were not; and in contexts B (and D) presentations of the clicker were paired with food whereas those of the tone were not. Mammillothalamic tract lesions disrupted initial acquisition of the conditional discrimination involving visual contexts (A and B), but not the formally equivalent discrimination involving thermal contexts (C and D). These results provide support for the suggestion that mammillothalamic tract lesions disrupt visuo-spatial encoding.

Research paper thumbnail of Perceptual learning with tactile stimuli in rats: Changes in the processing of a dimension

Journal of experimental psychology. Animal learning and cognition, 2016

Four experiments with male rats investigated perceptual learning involving a tactile dimension (A... more Four experiments with male rats investigated perceptual learning involving a tactile dimension (A, B, C, D, E), where A denotes 1 end of the continuum (e.g., a rough floor) and E the other (e.g., a smooth floor). In Experiment 1, rats given preexposure to A and E learned an appetitive discrimination between them more readily than those not given preexposure. Experiment 2a showed that rats preexposed to B and D acquired a discrimination between A and E more readily than those preexposed to A and E; and in Experiment 2b the same preexposure treatments had no effect on the acquisition of a discrimination between B and D. In Experiments 3a and 3b, rats given preexposure to C learned a discrimination between A and E more readily than those not given preexposure. Experiment 4 demonstrated that preexposure to a texture (e.g., B) that was adjacent to the to-be-discriminated textures (e.g., C and E) facilitated a discrimination between them relative to preexposure to their midpoint (D). Thes...

Research paper thumbnail of Stimulus Comparison and Perceptual Learning: Further Evidence and Evaluation from an Imprinting Procedure

The Quarterly Journal of Experimental Psychology

Two experiments used chicks to investigate the role of stimulus comparison in perceptual learning... more Two experiments used chicks to investigate the role of stimulus comparison in perceptual learning. In Experiment 1, chicks received exposure to two views of a jungle fowl, SV (side view) and BV (back view), intermixed within a session (mixed exposure), exposure to SV in one session and BV in a different session (separate exposure), or no exposure to either view. All chicks then received a heat-reinforced discrimination with SV and BV serving as discriminanda. Chicks given mixed exposure acquired the discrimination more readily than did either those given separate exposure or those given no exposure. In Experiment 2, all chicks received mixed exposure to the two stimuli. For one group the interval between presentations of the stimuli was short (short-mixed), for the other group it was long (long-mixed). Subjects in the long-mixed condition acquired the heat-reinforced discrimination more rapidly than those in the short-mixed condition. These results suggest that the intermixed nature...

Research paper thumbnail of BRIEF COMMUNICATIONS Associative Change in Connectionist Networks: An Addendum

The results of a recent study have provided direct support for the suggestion that conditional le... more The results of a recent study have provided direct support for the suggestion that conditional learning in rats is best characterized by a 3-layer connectionist network (M. J. Allman, J. Ward-Robinson, & R. C. Honey, 2004). In the 2 experiments reported here, rats were used to investigate the nature of the changes that occur when a stimulus compound is presented, whose components activate hidden units associated with food and no food, and either food or no food is presented. The results of both experiments, while controlling for the possible contribution of associations between these hidden units (within-layer links), provide evidence that the distribution of associative change between units in the hidden layer that are activated by the stimulus compound and those in the output layer (between-layer links) are unequal. They also indicate that associative change is more marked on trials on which no food was presented than on trials on which food was presented.

Research paper thumbnail of Imprinting, learning and development: from behaviour to brain and back

Trends in Neurosciences, 1998

Neural and behavioural analyses have shown that the formation of filial preferences in young, pre... more Neural and behavioural analyses have shown that the formation of filial preferences in young, precocial birds involves at least two separate processes. One process is an emerging predisposition to approach stimuli with the characteristics of the natural mother. The other (learning) process of filial imprinting results in chicks preferentially-approaching a stimulus to which they have been exposed and involves forming links between the components of the exposed stimulus. The neural substrate for the predisposition is different from that underlying imprinting, and different regions of the chick brain are involved in distinct aspects of learning about imprinting stimuli.

Research paper thumbnail of Exploring the spatiotopic frame using motion after-effects

Research paper thumbnail of The role of similarity in human associative learning

Journal of Experimental Psychology: Animal Behavior Processes, 2007

In 2 experiments, humans received sequences of patterns that were similar (AX3 BX, AY3 BY, AZ3 BZ... more In 2 experiments, humans received sequences of patterns that were similar (AX3 BX, AY3 BY, AZ3 BZ) or dissimilar (CX3 DY, CY3 DZ, CZ3 DX). The patterns were portrayed as bugs that could be eliminated with 2 insecticide sprays (red or blue). Either spray eliminated bugs with Features A and C, and participants learned by trial and error to use one spray (e.g., red) to eliminate bugs with Feature B and the other spray (e.g., blue) to eliminate those with Feature D. In Experiment 1, participants' spray choice for bugs with Feature A came to match that used to eliminate bugs with Feature B, but there was no such associative transfer between Features C and D. That is, similarity promoted associative transfer of responding between paired patterns when the features used to manipulate similarity (i.e., X, Y, and Z) were irrelevant. In Experiment 2, in which X, Y, and Z were relevant to the solution of configural discrimination, similarity hindered such associative transfer. These results complement those found in pigeons (R. A. Rescorla & D. J. Gillan, 1980) and indicate that similarity should not be accorded independent status as a principle of associative learning.

Research paper thumbnail of Analysis of the content of configural representations: The role of associatively evoked and trace memories

Journal of Experimental Psychology: Animal Behavior Processes, 2010

Two experiments examined the content of configural learning in rats. In Experiment 1, after simpl... more Two experiments examined the content of configural learning in rats. In Experiment 1, after simple pre-exposure to two hybrid contexts (AB and CD), rats acquired a configural discrimination involving two of the contexts (A and C) and two auditory stimuli (X and Y; AX3food, AY3no food, CX3no food, and CY3food). When rats were then placed in context B, they were more likely to respond to X than Y, and when they were placed in context D the reverse was the case. Experiment 2 demonstrated that rats can acquire a configural discrimination involving the presence of context (A) and its memory trace (a; AX3food, AY3no food, aX3no food, and aY3food). These results show that associatively provoked memories (Experiment 1) and memory traces (Experiment 2) can participate in configural discriminations.

Research paper thumbnail of Stimulus generalization as a function of stimulus novelty and familiarity in rats

Journal of Experimental Psychology: Animal Behavior Processes, 1990

Threeexpefiments used rats as subjects to investigate the generalization of conditioned respondin... more Threeexpefiments used rats as subjects to investigate the generalization of conditioned responding between stimuli as a function of the subjects' exposure to these cues prior to conditioning. Experiment I used a between-subjects design, food as the reinforcer, and measured the tendency ofsubjects to approach the site of food delivery during the stimuli. Generalization of this response was more marked when the training and test stimuli were equated in terms of their novelty (i.e., when both were novel or both were familiar) than when the stimuli differed in this respect (i.e., when one was novel and the other was familiar). Experiments 2a and 2b used within-subjects designs to confirm the reliability of the results of Experiment 1. Implications of these results for current theories of stimulus representation are discussed.

Research paper thumbnail of Involvement of the rat medial prefrontal cortex in novelty detection

Behavioral Neuroscience, 2002

The prefrontal cortex in humans has been implicated in processes that underlie novelty detection ... more The prefrontal cortex in humans has been implicated in processes that underlie novelty detection and attention. This study examined the contribution of the rat medial prefrontal cortex to novelty detection using the targeting, or orienting, response (OR) as a behavioral index. Lesions to the medial prefrontal cortex (specifically the prelimbic and infralimbic cortices) influenced neither the OR to a novel visual stimulus from a localized light source (V1), nor the change in this OR over the course of a series of exposures to V1. However, after exposure to V1, the OR to a 2nd visual stimulus from the same source, V2, was more pronounced in control rats than in lesioned rats. These results suggest that the medial prefrontal cortex in the rat contributes to the process of novelty detection.

Research paper thumbnail of Loss of the thalamic nuclei for "head direction" impairs performance on spatial memory tasks in rats

Behavioral Neuroscience, 2001

This study sought to characterize the effects of removing the nuclei of primary importance in rel... more This study sought to characterize the effects of removing the nuclei of primary importance in relaying the thalamic head direction signal to the hippocampal formation (the anterior dorsal [AD] and lateral dorsal [LD] nuclei) on the performance of a variety of spatial and nonspatial tasks. The results indicate that combined excitotoxic lesions of the AD and LD nuclei produce marked deficits on a variety of spatial tasks. These tasks included T-maze alternation and the ability to locate a hidden platform set at a fixed distance and fixed direction from a beacon in a Morris water maze. Although object recognition appeared unaffected, marked impairments were found in the ability to detect when an object was placed in a novel position (object-in-place memory).

Research paper thumbnail of Asymmetry in the discrimination of quantity by rats: The role of the intertrial interval

Learning & behavior, 2016

In three experiments, rats were trained to discriminate between 20 and five (Exps. 1 and 2), or b... more In three experiments, rats were trained to discriminate between 20 and five (Exps. 1 and 2), or between 40 and five (Exp. 3), black squares. The squares were randomly distributed in the center of a white background and displayed on a computer screen. For one group, the patterns containing the higher quantity of squares signaled the delivery of sucrose (+), whilst patterns with the lower quantity of squares did not (-). For the second group, sucrose was signaled by the lower, but not by the higher, quantity of squares. In Experiment 1, the intertrial interval (ITI) was a white screen, and the 20+/5- discrimination was acquired more readily than the 5+/20- discrimination. For Experiment 2, the ITI was made up of 80 black squares on a white background. In this instance, the 5+/20- discrimination was acquired more successfully than the 20+/5- discrimination. In Experiment 3, two groups were trained with a 40+/5- discrimination, and two with a 5+/40- discrimination. For one group from ea...

Research paper thumbnail of Hippocampal Lesions Disrupt an Associative Mismatch Process

The Journal of Neuroscience, 1998

Novel assays were used to assess inter alia whether the hippocampus is involved in detecting nove... more Novel assays were used to assess inter alia whether the hippocampus is involved in detecting novelty per se or in an associative mismatch process. During training, rats received two audiovisual sequences (tone-left constant light and clickleft flashing light). In both sham-operated control rats and those with excitotoxic hippocampal lesions, novel visual targets provoked an orienting response that habituated during training. Moreover, like sham-operated rats, rats with hippocampal lesions acquired associations between the elements of two audiovisual sequences. However, subsequent test trials in which the auditory stimuli preceding the visual targets were switched (click-left constant light and tone-left flashing light) provoked renewed orienting to the visual targets in sham-operated rats but not in hippocampal rats. These results support the view that hippocampal damage results in a failure to detect (or act on) mismatches that are generated when an auditory stimulus associatively evokes the memory of one visual stimulus and a different (familiar) visual stimulus is present in the environment.

Research paper thumbnail of The origins of individual differences in how learning is expressed in rats: A general-process perspective

Journal of experimental psychology. Animal learning and cognition, Oct 1, 2016

Laboratory rats can exhibit marked, qualitative individual differences in the form of acquired be... more Laboratory rats can exhibit marked, qualitative individual differences in the form of acquired behaviors. For example, when exposed to a signal-reinforcer relationship some rats show marked and consistent changes in sign-tracking (interacting with the signal; e.g., a lever) and others show marked and consistent changes in goal-tracking (interacting with the location of the predicted reinforcer; e.g., the food well). Here, stable individual differences in rats' sign-tracking and goal-tracking emerged over the course of training, but these differences did not generalize across different signal-reinforcer relationships (Experiment 1). This selectivity suggests that individual differences in sign- and goal-tracking reflect differences in the value placed on individual reinforcers. Two findings provide direct support for this interpretation: the palatability of a reinforcer (as measured by an analysis of lick-cluster size) was positively correlated with goal-tracking (and negatively ...

Research paper thumbnail of Representational Blending in Human Conditional Learning: Implications for Associative Theory

The Quarterly Journal of Experimental Psychology Section B, 2003

In two experiments, participants were presented with pictures of different foods (A, B, C, D, X,)... more In two experiments, participants were presented with pictures of different foods (A, B, C, D, X,) and learned which combinations resulted in an allergic reaction in a fictitious patient, MrX. In Problem 1, when Aor B (but not Cor D) was combined with food Xan allergic reaction occurred, and when C or D(but not A or B) was combined with Y an allergic reaction occurred. In Experiment 1, participants also received Problem 2 in which A, B, C, and Dinteracted with foods V and Weither in the same way as X and Y, respectively, or in a different way. Participants performed more proficiently in the former than in the latter condition. In Experiment 2, after training on Problem 1, participants judged whether or not novel combinations of foods (e.g., AB, CD, AD, CB) would cause an allergic reaction in MrX. They were no more likely to indicate that ABor CD would cause an allergic reaction than AD or CB, but made their judgements more rapidly and with greater confidence on AB and CDtrials than o...

Research paper thumbnail of Configural Learning without Reinforcement: Integrated Memories for Correlates of What, Where, and When

Quarterly Journal of Experimental Psychology, 2008

In 2 experiments we examined the ability of rats to form configural memories of what auditory sti... more In 2 experiments we examined the ability of rats to form configural memories of what auditory stimulus (X or Y) was presented where (Context A or B) and when (morning or afternoon). In both experiments, rats received morning presentations of X in Context A and Y in Context B and afternoon presentations of X in B and Y in A. Subsequently, at midday the rats were exposed to trials where X was paired with footshock whereas Y was not. We then assessed the degree of contextual fear in A and B in the morning and the afternoon. In the morning, rats showed more fear in A than in B, and in the afternoon they showed more fear in B than in A. These results indicate that rats can form configural memories that represent what (X or Y) was presented, where (A or B), and when (morning or afternoon).

Research paper thumbnail of Revisiting places passed: Sensitization of exploratory activity in rats with hippocampal lesions

Quarterly Journal of Experimental Psychology, 2007

We examined the involvement of the hippocampus in short-term changes in exploratory behaviour in ... more We examined the involvement of the hippocampus in short-term changes in exploratory behaviour in an open field (Experiment 1) and experimental contexts (Experiment 2). In Experiment 1, rats with excitotoxic lesions of the hippocampus were more likely to revisit recently visited zones within the open field than were control rats. Similarly, in Experiment 2 rats with hippocampal lesions showed greater exploration of a context that they had recently explored than a context that they had less recently explored. This short-term sensitization effect was not evident in control rats. These findings are consistent with the suggestion that the recent presentation of a stimulus has two opposing effects on behaviour, sensitization, and habituation, and that hippocampal lesions disrupt the short-term process responsible for habituation, but not that responsible for sensitization.

Research paper thumbnail of A novel contextual dimension for use with an operant chamber: From simple to hierarchical forms of learning

Journal of Experimental Psychology: Animal Behavior Processes, 2000

A novel procedure is described in which the floor temperatures (warm and cool) in an operant cham... more A novel procedure is described in which the floor temperatures (warm and cool) in an operant chamber are used as contextual cues in 2 experiments with rats. Experiment 1 demonstrated that rats learn the relationship between these thermal contexts and auditory stimuli that have been paired with them. Experiment 2 showed that thermal contexts can serve a conditional function that (a) reflects the operation of a mechanism that is common to conventional, visual contexts and (b) is bound to these contexts' ability to retrieve the nature of the relationship between the auditory stimuli and food. The experimental study of rodent behavior within psychology and neuroscience has been dominated by the use of the operant chamber. Even in its basic form, this apparatus provides the opportunity to present animals with a range of stimuli, manipulanda, and events of motivational significance. Moreover, the ambient or contextual cues that accompany being placed in such a chamber (its visual characteristics, odor, and so on) are also cues that animals readily learn about (see Bouton, 1991). As versatile as this apparatus is, it remains the case that the number of stimulus dimensions that are both available and readily controlled (principally, the auditory and visual dimensions) serves as a constraint on the experiments that can be conducted. For example, when an additional stimulus dimension is required, different odor cues have been used that require procedures designed to minimize contamination between them. These procedures can be either expensive or inconvenient (e.g., Hall & Honey, 1989). At a practical level, therefore, the study of rodent behavior in the laboratory would be facilitated by the development of a system that allows another dimension to be presented. Moreover, many of our conceptual models of animal learning and memory (e.g., Gluck & Myers, 1993; McLaren, Kaye, & Mackintosh, 1989; Pearce, 1994; Rescoda & Wagner, 1972) assume that the principles that underlie them will be as likely to operate in one (sensory) domain as another. Use of an additional dimension would provide a way of assessing the generality of those effects on which our understanding of learning and memory has developed. With these practical and theoretical considerations in mind, we describe the development and use of a novel addition to an operant

Research paper thumbnail of Associative modulation of the orienting response: Distinct effects revealed by hippocampal lesions

Journal of Experimental Psychology: Animal Behavior Processes, 2000

The ability of auditory stimuli to modulate rats' tendency to orient to visual targets wa... more The ability of auditory stimuli to modulate rats' tendency to orient to visual targets was assessed. In Experiment 1, trials where an auditory stimulus (A) signaled one visual array (X) were intermixed with unsignaled presentations of a second array (Y). Comparison of the orienting responses (ORs) to X and Y revealed that A produced a transient (unconditioned) and an emerging (conditioned) disruptive influence on the OR to X. In Experiments 2 and 3, trials where A signaled X were intermixed with others where another auditory stimulus (B) signaled Y. Stimulus A's ability to modulate the OR to X was then assessed by presenting A prior to test arrays containing both X and Y. Control rats were more likely to orient to Y than X (Experiments 2 and 3) and rats with excitotoxic lesions of the hippocampus were more likely to orient to X than Y (Experiment 3). These results show that auditory stimuli exert distinct modulatory influences on the OR to visual stimuli with which they are associated.

Research paper thumbnail of Acquired relational equivalence: Implications for the nature of associative structures

Journal of Experimental Psychology: Animal Behavior Processes, 1998

In 2 experiments, rats received discrimination training in which separate presentations of A and ... more In 2 experiments, rats received discrimination training in which separate presentations of A and B signaled a common pair of relationships or associations (X-, food and Y-. no food), whereas presentations of C and D signaled a different pair of relationships (X ~ no food and Y-* food). To assess the nature of the associative structures acquired during this training, rats then received 2 types of revaluation procedure: In Experiment 1, A was paired with shock and C was not. In Experiment 2, the relationships that A and B had previously signaled (X-, food and Y-~ no food) were paired with shock, whereas those that C and D had signaled (Y ~ food and X ~ no food) were not. After both types of revaluation treatment, rats showed greater generalized conditioned suppression in the presence of B than D. These results indicate that A, B, C, and D come to evoke memories of the relationships or associations that they have signaled.