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Rat autoshaping procedures generate two readily measurable conditioned responses: During lever presentations that have previously signaled food, rats approach the food well (called goal-tracking) and interact with the lever itself (called sign-tracking). We investigated how reinforced and nonreinforced trials affect the overall and temporal distributions of these two responses across 10-second lever presentations. In two experiments, reinforced trials generated more goal-tracking than sign-tracking, and nonreinforced trials resulted in a larger reduction in goal-tracking than sign-tracking. The effect of reinforced trials was evident as an increase in goal-tracking and reduction in sign-tracking across the duration of the lever presentations, and nonreinforced trials resulted in this pattern transiently reversing and then becoming less evident with further training. These dissociations are consistent with a recent elaboration of the Rescorla-Wagner model, HeiDI (Honey, R.C., Dwyer, D.M., & Iliescu, A.F. (2020a). HeiDI: A model for Pavlovian learning and performance with reciprocal associations. Psychological Review, 127, 829-852.), a model in which responses related to the nature of the unconditioned stimulus (e.g., goal-tracking) have a different origin than those related to the nature of the conditioned stimulus (e.g., sign-tracking)., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.)

Objective: To understand how firefighters' use of rules (i.e., standard operating procedures [SOPs]) and deliberative decision making (i.e., operational discretion [OD]) interacts with acute stress., Background: Current operational guidance for UK firefighters combines the provision of SOPs, for routine incidents, with the use of OD, under prescribed conditions (e.g., when there is a risk to human life). However, our understanding of the use of SOPs and OD is limited., Methods: Incident commanders (ICs; n = 43) responded to simulated emergency incidents, which either licensed the use of OD or required use of a SOP. Video footage of IC behavior was used to code their response as involving a SOP or OD, while levels of acute stress were assessed using a blood-based measure and self-report., Results: ICs were less likely to use OD selectively in the simulated emergency incident that licensed its use than in the one for which use of an SOP was appropriate; IC command level did not affect this pattern of results; and the incident that licensed OD resulted in more acute stress than the incident that required use of a SOP., Conclusion: SOPs and OD were not used in the manner prescribed by current operational guidance in simulated emergency incidents., Application: These results suggest that firefighter training in SOPs and OD should be augmented alongside personal resilience training, given the impact of stress on health and wellbeing, but also to improve the deployment of SOPs and OD under stress.

Pavlovian conditioning is evident in every species in which it has been assessed, and there is a consensus about its interpretation across behavioral, 1 , 2 brain, 3 , 4 , 5 , 6 and computational analyses 7 , 8 , 9 , 10 , 11 : conditioned behavior reflects the formation of a directional associative link from the memory of one stimulus (e.g., a visual stimulus) to another (e.g., food), with learning stopping when there is no error between the prediction generated by the visual stimulus and what happens next (e.g., food). This consensus fails to anticipate the results that we report here. In our experiments with rats, we find that arranging predictive (visual stimulus→food) and nonpredictive (food→visual stimulus) relationships produces marked and sustained changes in conditioned behaviors when the visual stimulus is presented alone. Moreover, the type of relationship affects (1) the distribution of conditioned behaviors related to the properties of both food (called goal-tracking) and the visual stimulus (called sign-tracking) and (2) when in the visual stimulus, these two behaviors are evident. These results represent an impetus for a fundamental shift in how Pavlovian conditioning is interpreted: animals learn about the relationship between two stimuli irrespective of the order in which they are presented, but they exhibit this knowledge in different ways. This interpretation and our new results are captured by a recent model of Pavlovian conditioning, 12 , 13 HeiDI, and both are consistent with the need for animals to represent the fact that the impact of a cause (e.g., the ingestion of nutrients or the bite of a predator) can be felt before or after the cause has been perceived., Competing Interests: Declaration of interests The authors declare no competing interests., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)

Three experiments investigated whether the nature of the temporal referent affects timing behaviour in rats. We used a peak procedure and assessed timing of food well activity as a function of whether the referent was an instrumental response (a lever press that resulted in the withdrawal of the lever) or a conditioned stimulus (CS) that was 2 s in Experiment 1, 500 ms in Experiment 2, and 800 ms in Experiment 3. In all experiments, the interval between the offset of the temporal referent and food was 5 s. The curve fits for each experiment revealed no differences in peak time, but magazine responding immediately following the CS was higher than following a lever press. This pattern of results was interpreted as reflecting a combination of (a) ambiguity in which component of the 500 ms-2-s auditory stimulus was serving as the referent and (b) response competition between lever pressing and magazine activity. Critically, these results suggest that peak timing in rats is unaffected by whether a lever press or CS serves as the referent. This conclusion is consistent with theoretical models of timing behaviour, but not with evidence from humans showing that the subjective perception of time is affected by whether the cause of an outcome was self-generated or not.

Higher-order conditioning results from a simple training procedure: Pairing two relatively neutral conditioned stimuli, A and X, allows properties separately conditioned to X (e.g., through pairing it with an unconditioned stimulus, US) to be evident during A. The phenomenon extends the range of ways in which Pavlovian conditioned responding can be expressed and increases its translational relevance. Given this relevance and the wealth of available behavioral analysis, it is a surprisingly underdeveloped territory for formal theoretical analysis. Here, we first provide a critical review of two (informal) classes of account for higher-order conditioning that reflect either: (a) processes that are analogous to Pavlovian conditioning, but involving associatively activated representations (e.g., A→US); or (b) the formation of an associative chain (e.g., A→X, and X→US). Our review first identifies fundamental theoretical and empirical challenges to both classes of account. We then develop a new computational model of higher-order conditioning that meets the challenges identified by showing: how reciprocal associations between A, X, and the US are formed and affect performance; and how the similarity of stimuli, their traces, and associatively retrieved representations modulate this process. The model generates a wealth of novel predictions, providing a platform for further empirical and theoretical analysis. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Robert A. Rescorla changed how Pavlovian conditioning was studied and interpreted. His empirical contributions were fundamental and theoretically driven. One involved testing a central tenet of the model that he developed with Allan R. Wagner. The Rescorla-Wagner learning rule uses a pooled error term to determine changes in a directional association between the representations of the conditioned stimulus (CS) and unconditioned stimulus (US). This learning rule predicts that 2 equally salient CSs (A and B) will undergo equivalent associative change when they are conditioned in compound (i.e., AB→US). Rescorla's results suggested that this was not the case (e.g., Rescorla, 2000). Here, we show that these results can be reconciled with a model that uses a learning rule with a pooled error term once that rule is applied equivalently to all of the stimuli presented on a given trial, and the resulting reciprocal associations (directly and indirectly) contribute to performance. This model, called HeiDI, integrates several features of Rescorla's research and theorizing while addressing an issue that he recognized required further analysis: how learning is translated into performance. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Exposure to two similar stimuli (AX and BX; e.g., two tastes) reduces the extent to which a conditioned response later established to BX generalizes to AX. This example of perceptual learning is more evident when AX and BX are exposed in an alternating manner (AX, BX, AX, BX,…) than when AX and BX occur in separate blocks (e.g., AX, AX,…BX, BX,…). We examined in male rats (N = 126) the impact of rapid alternation to AX and BX on generalization of a taste aversion from BX to AX. Experiment 1 showed that such alternating presentations (with 5-min intervals between AX and BX) reduced generalization relative to blocked exposure; but only as assessed by consumption levels and not by lick cluster size (an index of hedonic reactions). Experiment 1 also showed that the nature of exposure did not affect how A influenced performance to a novel conditioned taste, Y. Experiment 2 replicated the pattern of results involving the different influences of rapidly alternating and blocked exposure on generalization from BX to AX, and showed that this effect was only evident when rats received access to water during the 5-min intervals between AX and BX. These results reinforce parallels between perceptual learning effects in rats and humans, both at empirical and theoretical levels. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Pairing a neutral conditioned stimulus (CS) with a motivationally significant unconditioned stimulus (US) results in the CS coming to elicit conditioned responses (CRs). The widespread significance and translational value of Pavlovian conditioning are increased by the fact that pairing two neutral CSs (A and X) enables conditioning with X to affect behavior to A. There are two traditional informal accounts of such higher-order conditioning, which build on more formal associative analyses of Pavlovian conditioning. But, higher-order conditioning and Pavlovian conditioning have characteristics that are beyond these accounts: Notably, the two are influenced in different ways by the same experimental manipulations, and both generate conditioned responses that do not reflect the US per se . Here, we present a formal analysis that sought to address these characteristics., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Honey and Dwyer.)

Pavlovian conditioning results in individual variation in the vigor and form of acquired behaviors. Here, we describe a general-process model of associative learning (HeiDI; How excitation and inhibition determine ideo-motion) that provides an analysis for such variation together with a range of other important group-level phenomena. The model takes as its starting point the idea that pairings of a conditioned stimulus (CS) and an unconditioned stimulus (US) result in the formation of reciprocal associations between their central representations. The asymptotic values of these associations and the rate at which these are reached are held to be influenced by the perceived salience of the CS (α CS ) and US (β US ). Importantly, whether this associative knowledge is exhibited in behavior that reflects the properties of the CS (e.g., sign-tracking) or US (e.g., goal-tracking) is also influenced by the relative values of α CS and β US . In this way, HeiDI provides an analysis for both quantitative and qualitative individual differences generated by Pavlovian conditioning procedures., (© 2020 The Author(s).)

Associative treatments of how Pavlovian conditioning affects conditioned behavior are rudimentary: A simple ordinal mapping is held to exist between the strength of an association (V) between a conditioned stimulus (CS) and an unconditioned stimulus (US; i.e., V CS-US ) and conditioned behavior in a given experimental preparation. The inadequacy of this simplification is highlighted by recent studies that have taken multiple measures of conditioned behavior: Different measures of conditioned behavior provide the basis for drawing opposite conclusions about V CS-US across individual animals. Here, we develop a simple model involving reciprocal associations between the CS and US (V CS-US and V US-CS ) that simulates these qualitative individual differences in conditioned behavior. The new model, HeiDI (How excitation and inhibition Determine Ideo-motion), enables a broad range of phenomena to be accommodated, which are either beyond the scope of extant models or require them to appeal to additional (learning) processes. It also provides an impetus for new lines of inquiry and generates novel predictions. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Pavlovian conditioning procedures produce marked individual differences in the form of conditioned behavior. For example, when rats are given conditioning trials in which the temporary insertion of a lever into an operant chamber (the conditioned stimulus, CS) is paired with the delivery of food (the unconditioned stimulus, US), they exhibit knowledge of the lever-food relationship in different ways. For some rats (known as sign-trackers), interactions with the lever dominate, while for others (goal-trackers), approaching the food well dominates. A formal model of Pavlovian conditioning (HeiDI) attributes such individual differences in behavior to variations in the perceived salience of the CS and US. An application of the model in which the perceived salience of the CS declines (i.e., adapts) across its duration predicts changes in these individual differences within the presentation of the CS: The sign-tracking bias is predicted to decline and goal-tracking bias is predicted to increase across the presentation of a lever. The accuracy of these predictions was confirmed through analysis of archival data from female and male rats. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

The model elaborated here adapts the influential pooled error term, first described by Wagner and Rescorla (Rescorla & Wagner, 1972; Wagner & Rescorla, 1972), to govern the formation of reciprocal associations between any pair of stimuli that are presented on a given trial. In the context of Pavlovian conditioning, these stimuli include various conditioned and unconditioned stimuli. This elaboration enables the model to deal with cue competition phenomena, including the relative validity effect, and evidence implicating separate error terms and attentional processes in association formation. The model also includes a performance rule, which provides a natural basis for (individual) variation in the strength and nature of conditioned behaviors that are observed in Pavlovian conditioning procedures. The new model thereby begins to address theoretical and empirical issues that were apparent when the Rescorla-Wagner model was first described, together with research inspired by the model over the ensuing 50 years. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Texture is often used as a convenient stimulus dimension to study aspects of discrimination learning in rodents. However, the basis of texture discrimination learning is often left untested: Although learning could involve the whisker system, it could also be based on other senses (e.g., olfactory or visual). Here, we investigated whether mice use their whisker system to learn texture discriminations. Mice were placed in an apparatus illuminated with a dim red light, and the mice had to learn which of 2 sawdust-filled bowls contained a buried reward. The outer surfaces of the bowls were 3-D printed with different textures (grooved or smooth). Within a 60-min session, mice learned to dig in 1 bowl (e.g., grooved) rather than the other (e.g., smooth) to gain the reward. This texture discrimination and an equivalent odor discrimination were retained overnight (Experiments 1 and 2); and whisker trimming disrupted learning based on the texture of the bowls but not learning based on the odor of the sawdust in the bowls (Experiments 3 and 4). These results provide a secure basis upon which to investigate the behavioral and brain basis of texture learning in rodents. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

The biological basis of the increased risk for psychiatric disorders seen in 15q11.2 copy number deletion is unknown. Previous work has shown disturbances in white matter tracts in human carriers of the deletion. Here, in a novel rat model, we recapitulated low dosage of the candidate risk gene CYFIP1 present within the 15q11.2 interval. Using diffusion tensor imaging, we first showed extensive white matter changes in Cyfip1 mutant rats, which were most pronounced in the corpus callosum and external capsule. Transmission electron microscopy showed that these changes were associated with thinning of the myelin sheath in the corpus callosum. Myelin thinning was independent of changes in axon number or diameter but was associated with effects on mature oligodendrocytes, including aberrant intracellular distribution of myelin basic protein. Finally, we demonstrated effects on cognitive phenotypes sensitive to both disruptions in myelin and callosal circuitry.

Pavlovian conditioning procedures result in dramatic individual differences in the topography of learnt behaviors in rats: When the temporary insertion of a lever into an operant chamber is paired with food pellets, some rats (known as sign-trackers) predominantly interact with the lever, while others (known as goal-trackers) predominantly approach the food well. Two experiments examined the sensitivity of these two behaviors to changing reinforcement contingencies in groups of male and female rats exhibiting the different phenotypes (i.e., sign-trackers and goal-trackers). In both phenotypes, behavior oriented to the food well was more sensitive to contingency changes (e.g., a reversal in which of two levers was reinforced) than was lever-oriented behavior. That is, the nature of the two behaviors differed independently of the rats in which they were manifest. These results indicate that the behavioral phenotypes reflect the parallel operation of a stimulus-stimulus associative process that gives rise to food-well activity and a stimulus-response process that gives rise to lever-oriented activity, rather than the operation of a single process (e.g., stimulus-stimulus) that generates both behaviors. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Three experiments investigated mediated configural learning in male rats. In Experiment 1, after exposure to audio-visual compounds AX and BY, rats received trials where X was paired with shock, and Y was not. The idea that conditioning with X enables the evoked configural representation of AX to be linked to shock received support from the facts that while AX provoked more fear than BX, there was no difference between BY and AY. Similarly, Experiment 2 showed that after exposure to AX and BY, separate pairings of X and Y with shock resulted in more fear to AX and BY than AY and BX. In Experiment 3, rats in group consistent received separate exposures to A and X in Context C, and B and Y in D, while those in group inconsistent received A and X (and B and Y) in both C and D. After rats had received shocks in both C and D, rats in group consistent showed more fear to AX and BY than to BX and AY, but this was not the case in group inconsistent. These results indicate that configural representations, formed either by presenting auditory and visual stimuli as parts of a compound or in a shared context, are subject to a process of mediated learning.

The conditions under which the hippocampus contributes to learning about spatio-temporal configural patterns are not fully established. The aim of Experiments 1-4 was to investigate the impact of hippocampal lesions on learning about where or when a reinforcer would be delivered. In each experiment, the rats received exposure to an identical set of patterns (i.e., spotted+morning, checked+morning, spotted+afternoon and checked+afternoon); and the contexts (Experiment 1), times of day (Experiment 2), or their configuration (Experiments 3 and 4) signalled whether or not a reinforcer would be delivered. The fact that hippocampal damage did not disrupt the formation of simple or configural associations involving spatio-temporal patterns is surprising, and suggests that the contribution of the hippocampus is restricted to mediated learning (or updating) involving spatio-temporal configurations., (Copyright © 2017 Elsevier Inc. All rights reserved.)

The animal kingdom contains species with a wide variety of sensory systems that have been selected to function in different environmental niches, but that are also subject to modification by experience during an organism's lifetime. The modification of such systems by experience is often called perceptual learning. In rodents, the classic example of perceptual learning is the observation that simple preexposure to two visual stimuli facilitates a subsequent (reinforced) discrimination between them. However, until recently very little behavioral research had investigated perceptual learning with tactile stimuli in rodents, in marked contrast to the wealth of information about plasticity in the rodent somatosensory system. Here we present a selective review of behavioral analyses of perceptual learning with tactile stimuli, alongside evidence concerning the potential bases of such effects within the somatosensory system.

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 correlated with sign-tracking); and sating rats with a reinforcer affected goal-tracking but not sign-tracking (Experiment 2). These results indicate that the observed individual differences in sign- and goal-tracking behavior arise from the interaction between the palatability or value of the reinforcer and processes of association as opposed to dispositional differences (e.g., in sensory processes, "temperament," or response repertoire). (PsycINFO Database Record, ((c) 2016 APA, all rights reserved).)

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). These novel perceptual learning effects are interpreted as reflecting a redistribution of processing between the notional elements of the texture dimension. (PsycINFO Database Record, ((c) 2016 APA, all rights reserved).)

Successful retrieval of a memory for an entire pattern of stimulation by the presentation of a fragment of that pattern is a critical facet of memory function. We examined processes of pattern completion using novel sensory preconditioning procedures in rats that had either received sham lesions (group Sham) or lesions of the hippocampus (group HPC). After exposure to two audio-visual patterns (AX and BY) rats received fear conditioning with X (but not Y). Subsequent tests assessed fear to stimulus compounds (e.g., AX versus BX; Experiment 1) or elements (A versus B; Experiment 2). There was more fear to AX than BX in group Sham but not group HPC, while there was more fear to A than B in group HPC, but not in group Sham. This double dissociation suggests that pattern completion can be based upon separable processes that differ in their reliance on the hippocampus., (Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.)

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 each of these pairs, the training trials were separated by a white ITI, and the 40+/5- discrimination was acquired more readily than the 5+/40- discrimination. For the remaining two groups, the training trials were not separated by an ITI, and the two groups acquired the task at approximately the same rate. The results indicate that the cues present during the ITI play a role in the asymmetrical acquisition of magnitude discriminations based on quantity.

Decisions made by operational commanders at emergency incidents have been characterized as involving a period of information gathering followed by courses of action that are often generated without explicit plan formulation. We examined the efficacy of goal-oriented training in engendering explicit planning that would enable better communication at emergency incidents. While standard training mirrored current operational guidance, goal-oriented training incorporated "decision controls" that highlighted the importance of evaluating goals, anticipated consequences, and risk/benefit analyses once a potential course of action has been identified. In Experiment 1, 3 scenarios (a house fire, road traffic collision, and skip fire) were presented in a virtual environment, and in Experiment 2 they were recreated on the fireground. In Experiment 3, the house fire was recreated as a "live burn," and incident commanders and their crews responded to this scenario as an emergency incident. In all experiments, groups given standard training showed the reported tendency to move directly from information gathering to action, whereas those given goal-oriented training were more likely to develop explicit plans and show anticipatory situational awareness. These results indicate that training can be readily modified to promote explicit plan formulation that could facilitate plan sharing between incident commanders and their teams., ((c) 2015 APA, all rights reserved).)

In order to evaluate 1 account for the asymmetry that has been found with discriminations based on stimulus magnitude, in 5 autoshaping experiments, 2 groups of pigeons received a discrimination between 5 and 20 squares presented on a TV screen. One group received a 20+/5- discrimination, with food signaled by 20 squares but not 5 squares; the other group received the opposite discrimination, 5+/20-. The 20+/5- discrimination was acquired more readily than 5+/20- in Experiments 1, 3a, 3b, and 4. For Experiment 1, the screen was white for the intertrial interval (ITI) and the stimuli were black squares on a white background; for Experiment 3a, the screen was black for the ITI and the stimuli were black squares on a white background; and for Experiments 3b and 4, the screen was white for the ITI and the stimuli were white squares on a black background. In Experiment 2, the stimuli were black squares on a white background, but they were separated by an ITI in which 288 black squares were presented against a white background. The 20+/5- discrimination was now acquired more slowly than the 5+/20- discrimination. The asymmetry in the acquisition of the magnitude discriminations in each experiment is attributed to inhibition being associated with the stimuli present during the ITI. The generalization of this inhibition, along a dimension related to the number of squares on the screen, is then assumed to disrupt the acquisition of 1 discrimination to a greater extent than the other., ((c) 2015 APA, all rights reserved).)

Objective: The aim of this study was to better understand the nature of decision making at operational incidents in order to inform operational guidance and training., Background: Normative models of decision making have been adopted in the guidance and training for emergency services. In these models, it is assumed that decision makers assess the current situation, formulate plans, and then execute the plans. However, our understanding of how decision making unfolds at operational incidents remains limited., Method: Incident commanders, attending 33 incidents across six U.K. Fire and Rescue Services, were fitted with helmet-mounted cameras, and the resulting video footage was later independently coded and used to prompt participants to provide a running commentary concerning their decisions., Results: The analysis revealed that assessment of the operational situation was most often followed by plan execution rather than plan formulation, and there was little evidence of prospection about the potential consequences of actions. This pattern of results was consistent across different types of incident, characterized by level of risk and time pressure, but was affected by the operational experience of the participants., Conclusion: Decision making did not follow the sequence of phases assumed by normative models and conveyed in current operational guidance but instead was influenced by both reflective and reflexive processes., Application: These results have clear implications for understanding operational decision making as it occurs in situ and suggest a need for future guidance and training to acknowledge the role of reflexive processes., (© 2015, Human Factors and Ergonomics Society.)

Two experiments investigated the capacity of rats to learn configural discriminations requiring integration of contextual (where) with temporal (when) information. In Experiment 1, during morning training sessions, food was delivered in context A and not in context B, whereas during afternoon sessions food was delivered in context B and not in context A. Rats acquired this discrimination over the course of 20 days. Experiment 2 employed a directly analogous aversive conditioning procedure in which footshock served in place of food. This procedure allowed the acquisition of the discrimination to be assessed through changes in activity to the contextual + temporal configurations (i.e., inactivity or freezing) and modulation of the immediate impact of footshock presentations (i.e., post-shock activity bursts). Both measures provided evidence of configural learning over the course of 12 days, with a final test showing that the presentation of footshock resulted in more post-shock activity in the nonreinforced than reinforced configurations. These behavioral effects reveal important parallels between (i) configural discrimination learning involving components allied to episodic memory and (ii) simple conditioning.

The view that filial imprinting might serve as a useful model system for studying the neurobiological basis of memory was inspired, at least in part, by a simple idea: acquired filial preferences reflect the formation of a memory or representation of the imprinting object itself, as opposed to the change in the efficacy of stimulus-response pathways, for example. We provide a synthesis of the evidence that supports this idea; and show that the processes of memory formation observed in filial imprinting find surprisingly close counterparts in other species, including our own., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

One product of simple exposure to similar visual stimuli is that they become easier to distinguish. The early visual cortex and other brain areas (such as the prefrontal cortex) have been implicated in such perceptual learning effects, but the anatomical specificity within visual cortex and the relationship between sensory cortex and other brain areas has yet to be examined. Moreover, while variations in the schedule (rather than merely the amount) of exposure influence experience-dependent improvement in discrimination, the neural sequelae of exposure schedule have not been fully investigated. In an event-related fMRI study, participants were exposed to confusable pairs of faces, scenes and dot patterns, using either intermixed or blocked presentation schedules. Participants then performed same/different judgements with exposed and novel pairs of stimuli. Stimulus independent activation, which was correlated with experience-dependent improvement in discrimination, was seen in frontal areas (e.g. frontal and supplementary eye fields and dorsolateral prefrontal cortex) and in early visual cortex (V1-4). In all regions, the difference in activation between exposed and novel stimuli decreased as a function of the degree of discrimination improvement. Overall levels of BOLD activation differed across regions, consistent with the possibility that, as a consequence of experience, processing shifts from initial engagement of early visual regions to higher order visual areas. Similar relationships were observed when contrasting intermixed with blocked exposure, suggesting that the schedule of exposure primarily influences the degree of, rather than the mechanisms for, discrimination performance.

The cognitive deficits observed in schizophrenia have been characterized as a failure to utilize task-setting information to guide behaviour, especially in situations in which there is response conflict. Recently, we have provided support for this account; high schizotypy individuals demonstrated inferior biconditional discrimination performance compared to low scorers, but were not impaired on a simple discrimination that did not require the use of task-setting cues. These results may, however, also be explained by the way in which individuals with high schizotypy process stimulus compounds. Here, we examine the initial approaches to solving biconditional and control discrimination tasks of participants with high and low schizotypy scores. In particular, we focus on performance during the first block of training trials to capture processing style before the acquisition of the discrimination tasks. Participants scoring highly on the introvertive anhedonia subscale (which has been allied to the negative and cognitive symptoms of schizophrenia) demonstrated better biconditional performance during the first block of training trials than did low-schizotypy individuals, consistent with a highly elemental approach to stimulus processing. Subsequent recognition tests confirmed this analysis demonstrating that the pattern of performance observed in participants with high schizotypy was associated with a failure to discriminate conjunctions of items that had been seen before from those that had not. These results suggest that the negative/cognitive symptoms of schizophrenia may reflect an extreme bias towards elemental, as opposed to configural, processing of stimulus conjunctions.

Two experiments investigated how the schizotypal characteristics of unusual experiences modulate changes in attention to alphanumeric stimuli. In the first stage of both experiments, participants were required to attend and respond to either Arabic numerals or Latin letters; with the four exemplars from each dimension being presented on a different number of occasions (0, 5, 10, 20). During the test in Experiment 1 (n=103), speeded alphanumeric decisions were more accurate for the novel than familiar exemplars, irrespective of whether they had been attended to or not. This influence of familiarity was not modulated by schizotypy. During the test in Experiment 2 (n=128), learning that the attended dimension predicted the presentation of the symbol X (or the absence of X) proceeded more rapidly than learning the corresponding predictions involving the unattended dimension. In the case of novel exemplars, but not familiar exemplars, this modulation of learning by attention was reduced as schizotypy scores increased. Taken together, these results show that schizotypal characteristics do not modulate the influence of familiarity on performance (Experiment 1), but do have an influence on attention, which is best characterised as one on tuning attention to stimulus dimensions rather than individual stimuli., (Crown Copyright © 2013. Published by Elsevier B.V. All rights reserved.)

The central concern of associative learning theory is to provide an account of behavioral adaptation that is parsimonious in addressing three key questions: (1) under what conditions does learning occur, (2) what are the associative structures involved, and (3) how do these affect behavior? The principle focus here is on the second question, concerning associative structures, but we will have cause to touch on the others in passing. This question is one that has exercised theorists since Pavlov's descriptions of the conditioning process, where he identifies the shared significance of the study of conditioned reflexes for psychologists and neuroscientists alike., (Copyright © 2013 Elsevier Inc. All rights reserved.)

The source of renewal of instrumental responding in rats was investigated. In Experiment 1, two responses (R1 and R2) were reinforced with one outcome (O1) in contexts A and B (i.e., R1→O1, R2→O1), and then R2 was extinguished in A and R1 was extinguished in B. At test, the rate of R1 was higher than that of R2 in context A, and the reverse was the case in context B: Renewed responding was independent of the Pavlovian context→O1 associations. In Experiment 2, all rats received R1→O1 and R2→O2 trials in A and then were placed in B, where they were sated on O2 and either did (Group Extinction) or did not (Group No Extinction) receive concurrent extinction of R1 and R2. At test, we found more responding in A than in B for Group Extinction, but not for Group No Extinction, and the renewed responding in A was as sensitive to the current value of the outcome as responding that had not been subject to extinction (i.e., the rate was higher for R1 than for R2). That is, the renewed responding was goal-directed. These results identify the removal of contextual inhibion of either the response or the response→outcome associaon as potenal bases for renewal, and the response→outcome associaon as the source of renewed responding.

It is debated whether subregions within the medial temporal lobe (MTL), in particular the hippocampus (HC) and perirhinal cortex (PrC), play domain-sensitive roles in learning. In the present study, two patients with differing degrees of MTL damage were first exposed to pairs of highly similar scenes, faces, and dot patterns and then asked to make repeated same/different decisions to preexposed and nonexposed (novel) pairs from the three categories (Experiment 1). We measured whether patients would show a benefit of prior exposure (preexposed > nonexposed) and whether repetition of nonexposed (and preexposed) pairs at test would benefit discrimination accuracy. Although selective HC damage impaired learning of scenes, but not faces and dot patterns, broader MTL damage involving the HC and PrC compromised discrimination learning of scenes and faces but left dot pattern learning unaffected. In Experiment 2, a similar task was run in healthy young participants in the MRI scanner. Functional region-of-interest analyses revealed that posterior HC and posterior parahippocampal gyrus showed greater activity during scene pattern learning, but not face and dot pattern learning, whereas PrC, anterior HC, and posterior fusiform gyrus were recruited during discrimination learning for faces, but not scenes and dot pattern learning. Critically, activity in posterior HC and PrC, but not the other functional region-of-interest analyses, was modulated by accuracy (correct > incorrect within a preferred category). Therefore, both approaches revealed a key role for the HC and PrC in discrimination learning, which is consistent with representational accounts in which subregions in these MTL structures store complex spatial and object representations, respectively.

Four experiments with rats examined the origin of outcome-selective Pavlovian-to-instrumental transfer (PIT). Experiment 1 used a standard procedure, where outcomes were embedded within extended conditioned stimuli (CSs), to demonstrate the basic effect: Pavlovian stimuli augmented instrumental lever presses that had been paired with the same outcomes. Experiments 2 and 3 showed that after instrumental conditioning, whereas a conditioned stimulus (CS) trained using a backward conditioning procedure produced outcome-selective PIT, forward conditioning with a CS did not. These results are consistent with the idea that backward conditioning results in the outcome provoking its associated instrumental response during the CS and thereby allows a stimulus-response association to be acquired that directly generates outcome-selective PIT at test. Experiment 4 provided direct support for the assumptions that underlie this stimulus-response analysis. These results, and other paradoxical effects of the Pavlovian relationship, are incongruent with accounts of outcome-selective PIT that rely on a stimulus-outcome-response chain.

Three experiments examined the encoding specificity of associations using sensory preconditioning procedures in rats. In Experiment 1a, after exposure to two compounds (AX and BY), X (but not Y) was either followed by shock after a trace interval (Group Trace) or immediately followed by shock (Group Immediate). AX elicited less activity than BX (i.e., more fear) in Group Trace, but equivalent activity levels in Group Immediate. These results, replicated using a within-subjects design in Experiment 1b, indicate that the presence of A (on AX trials) generates fear because it associatively evokes X's memory into the same state as it was associated with the shock during (trace) conditioning. In Experiment 2, after exposure to AX and BY, X (but not Y) was immediately followed by shock. As in Experiment 1a, presentations of AX and BX elicited equivalent levels of fear, but there was more fear in the trace period after AX than in the trace period after BX. This finding suggests that during aversive conditioning, the associatively provoked memory of A was part of the conditioned complex, and that the trace of AX was more likely to activate this memory than was the trace of BX.

After two neutral stimuli have been paired (AB), directly conditioning a response to one of them (A) will also be reflected in a change in responding to the other (B). Standard accounts of this sensory preconditioning effect assume that it is mediated by a memory involving the stimulus that was directly conditioned (i.e., A). The reliance on this shared pathway implies that sensory preconditioning (involving B) and direct conditioning (involving A) should support qualitatively similar patterns of responding. In three experiments, directly pairing A with lithium chloride (LiCl) delivery resulted in both a reduction in consumption of A (i.e., avoidance) and a reduction in the size of licking clusters it elicits (i.e., aversion). In contrast, the sensory preconditioning effect resulted in a reduction in the consumption of B but no change in the nature of the licking response that it elicited; and a similar dissociation was observed after trace conditioning. These dissociations involving direct conditioning and sensory preconditioning, observed over a range of flavor concentrations and different doses of LiCl, undermine standard accounts of sensory preconditioning that are based on the assumption of stimulus substitution., ((PsycINFO Database Record (c) 2012 APA, all rights reserved).)

The formation of stable social attachments requires that the specific physical characteristics of kith and kin are rapidly encoded, and that the resulting memories are updated when these characteristics gradually change. The idea that memories are updated in this way contrasts with influential exemplar models of memory, wherein each new pattern of characteristics should establish a new memory. Here, two experiments demonstrate a rapid form of memory updating in human face processing: An updated memory of a set of images of faces, varying in identity or age, is more likely to develop when these images from part of a gradually changing, rather than an abruptly changing, sequence or stream. These findings, while inconsistent with some exemplar theories, provide both a compelling demonstration of memory updating and insights into the nature of this process. They also represent a fresh impetus for theories wherein memory involves a process of evolution as opposed to mere replication of exemplars., ((PsycINFO Database Record (c) 2012 APA, all rights reserved).)

Three experiments in rats investigated the generalization of conditioned fear from one context (B) to both a preexposed context (A) and a novel context (C). In each experiment, when the conditioning context (B) had been preexposed, there was greater generalization to context A than to context C; but when B was novel at the outset of conditioning this difference between A and C was not observed. The implications of these results for associative treatments of the development of contextual memories are evaluated.

Rats received either a common-cause (i.e., A→B, A→food) or a causal-chain training scenario (i.e., B→A, A→food) before their tendency to approach the food magazine during the presentation of B was assessed as a function of whether it was preceded by a potential alternative cause. Causal model theory predicts that the influence of an alternative cause should be restricted to the common-cause scenario. In Experiment 1, responding to B was reduced when it occurred after pressing a novel lever during the test phase. This effect was not influenced by the type of training scenario. In Experiment 2, rats were familiarized with the lever prior to test by training it as a potential cause of B. After this treatment, the lever now failed to influence test responding to B. In Experiment 3, rats given common-cause training responded more to B when it followed a cue that had previously been trained as a predictor of B, than when it followed another stimulus. This effect was not apparent in rats that received causal-chain training. This pattern of results is the opposite of that predicted by causal model theory. Thus, in three experiments, the presence of an alternative cause failed to influence test responding in manner consistent with causal model theory. These results undermine the application of causal model theory to rats, but are consistent with associative analyses., ((c) 2012 APA, all rights reserved.)

Instrumental performance in rats with hippocampal lesions is insensitive to the degradation of action-outcome contingencies, but sensitive to the effects of selective devaluation by satiation. One interpretation of this dissociation is that damage to the hippocampus impairs the formation of context-outcome associations upon which the effect of contingency degradation, but not selective satiation, relies. Here, we provide a direct assessment of this interpretation, and showed that conditioned responding to contexts did not show sensitivity to selective satiation (Experiment 1), and confirmed that instrumental performance was sensitive to selective satiation (Experiment 2) following hippocampal cell loss., (Copyright © 2011 Elsevier Inc. All rights reserved.)

The formation of an integrated memory for a pattern of stimulation could be based on the elements of that pattern becoming directly linked to one another, or by each of the elements becoming linked to a shared separate configural representation. These 2 accounts have proven difficult to discriminate between. Here, rats received exposure to four patterns of stimulation, each consisting of an auditory stimulus, a visual context, and a time of day; and we examined whether pre-training lesions to the hippocampus influenced memory for the patterns. These lesions abolished pattern memory that required configural processes (Experiments 1A and 1B) but had no effect on pattern memory that could be supported by elemental processes (Experiment 2). This dissociation provides support for the views that elemental and configural processes ordinarily support pattern memory and that rats with lesions to the hippocampus are left reliant on elemental processes. (, (PsycINFO Database Record (c) 2011 APA, all rights reserved).)

Within-subjects procedures were used to assess the influence of stimulus comparison on perceptual learning in humans. In Experiment 1, participants received intermixed (A, A', A, A',…) or blocked (B, B,…, B', B',…) exposure to pairs of similar female faces. In a subsequent same/different discrimination task, participants were more accurate when the test involved A and A' than when it involved B and B' (or novel faces: C and C'). This perceptual learning effect was reduced by placing a visual distractor (*: either another face or a checkerboard) between successive presentations of the faces during the exposure stage (e.g., A - * - A'). The attenuation of the intermixed versus blocked difference was particularly marked when faces were used as the distractor. In Experiment 2, this reduction in perceptual learning was more marked when * was positioned between the pairs of intermixed faces (i.e., A - * - A') than when it preceded and succeeded those faces (i.e., * - A - A' - *). These results provide the first direct evidence that the opportunity to compare stimuli plays a causal role in supporting perceptual learning. They also support the specific view that perceptual learning reflects an interaction between a short-term habituation process, that ordinarily biases processing away from the frequently presented common elements and toward their less frequently presented unique elements, and a long-term representational process that reflects this bias., (PsycINFO Database Record (c) 2011 APA, all rights reserved)

Within-subjects procedures with rats assessed the associative structures acquired during conditioning trials in which the interval between the stimuli and food was either short or long (i.e., A-10 s→food and B-40 s→food). In Experiments 1 and 2, after these conditioning trials, A and B served as second-order reinforcers for 2 further stimuli (i.e., X→A and Y→B); whereas Experiment 3 used a sensory preconditioning procedure in which X→A and Y→B trials occurred before the conditioning trials, and rats were finally tested with X and Y. In each experiment, Y elicited greater responding at test than did X. This finding supports the contention that the long-lived trace of B (associated with food on B-40 s→food trials) is more similar to the memory of B that was associatively provoked by Y, than is the short-lived trace of A (associated with food on A-10 s→food trials) to the memory of A that was associatively provoked by X. These conclusions were reinforced by the effects of a neural manipulation that disrupted discrimination learning involving the short traces of stimuli but not the long traces of the same stimuli., (PsycINFO Database Record (c) 2011 APA, all rights reserved)

A novel association can form between two memories even when the events to which they correspond are not physically present. For example, once an integrated memory has formed that binds the (when, where, and what) components of an event together, this memory can be triggered by one of its components, and updated with coincident information in the environment. The neural basis of this form of retrieval-mediated learning is unknown. Here, we show, for the first time, that NMDA receptors in the rat hippocampus are required for retrieval-mediated learning involving episodes, but not for the expression of such learning or for retrieval-mediated learning involving simple associations between the components of episodes. These findings provide a novel insight into learning processes that serve the desirable function of integrating stored information with new information, but whose operation might also provide a substrate for some of the cognitive symptoms of schizophrenia and Alzheimer's disease.

Cognitive impairments in schizophrenia have been characterized as reflecting a core deficit in the maintenance or use of task-setting cues to mediate appropriate ongoing behaviour. This analysis suggests that cognitive deficits in schizophrenia will be particularly evident when different task-setting cues dictate when different responses are required by the same stimuli. One simple task in which task-setting cues are required is a biconditional discrimination. Here we examined the performance of participants with high and low schizotypy scores (Mason, Claridge, & Jackson, 1995) on a biconditional discrimination and an otherwise equivalent, control discrimination that did not require the use of task-setting cues. Participants scoring highly on the Introvertive Anhedonia subscale (which has been allied to the negative and cognitive symptoms of schizophrenia) performed poorly on the biconditional, but not on the control, discrimination. No other subscales demonstrated a significant influence on either biconditional or control performance.

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; AX→food, AY→no food, CX→no food, and CY→food). 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; AX→food, AY→no food, aX→no food, and aY→food). These results show that associatively provoked memories (Experiment 1) and memory traces (Experiment 2) can participate in configural discriminations., (2010 APA, all rights reserved)

Rats with lesions of the perirhinal cortex and a control group were required to find a platform in 1 corner of a white rectangle and in the reflection of this corner in a black rectangle. Test trials revealed that these groups were able to integrate information regarding the shape of the pool and the color of its walls (black or white) to identify the correct location of the platform. A clear effect of the perirhinal cortex lesions was, however, revealed using an object recognition task that involved the spontaneous exploration of novel objects. The results challenge the view that the perirhinal cortex enables rats to solve discriminations involving feature ambiguity.