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Temporal preparation is the cognitive function that takes place when anticipating future events. This is commonly considered to involve a process that maximizes preparation at time points that yield a high hazard. However, despite their prominence in the literature, hazard-based theories fail to explain the full range of empirical preparation phenomena. Here, we present the formalized multiple trace theory of temporal preparation (fMTP), an integrative model which develops the alternative perspective that temporal preparation results from associative learning. fMTP builds on established computational principles from the domains of interval timing, motor planning, and associative memory. In fMTP, temporal preparation results from associative learning between a representation of time on the one hand and inhibitory and activating motor units on the other hand. Simulations demonstrate that fMTP can explain phenomena across a range of time scales, from sequential effects operating on a time scale of seconds to long-term memory effects occurring over weeks. We contrast fMTP with models that rely on the hazard function and show that fMTP’s learning mechanisms are essential to capture the full range of empirical effects. In a critical experiment using a Gaussian distribution of foreperiods, we show the data to be consistent with fMTP’s predictions and to deviate from the hazard function. Additionally, we demonstrate how changing fMTP’s parameters can account for participant-to-participant variations in preparation. In sum, with fMTP we put forward a unifying computational framework that explains a family of phenomena in temporal preparation that cannot be jointly explained by conventional theoretical frameworks.

BackgroundActive learning relies on students' engagement with teachers, study materials and/or each other. Although medical education has adopted active learning as a core component of medical training, teachers have difficulties recognising when and why their students engage or disengage and how to teach in ways that optimise engagement. With a better understanding of the dynamics of student engagement in small-group active learning settings, teachers could be facilitated in effectively engaging their students.MethodsWe conducted a video-stimulated recall study to explore medical students' engagement during small-group learning activities. We recorded one teaching session of two different groups and selected critical moments of apparent (dis)engagement. These moments served as prompts for the 15 individual semi-structured interviews we held. Interview data were analysed using Template Analysis style of thematic analysis. To guide the analysis, we used a framework that describes student engagement as a dynamic and multidimensional concept, consisting of behavioural, cognitive and emotional components.ResultsThe analysis uncovered three main findings: (1) In-class student engagement followed a spiral-like pattern. Once students were engaged or disengaged on one dimension, other dimensions were likely to follow suit. (2) Students' willingness to engage in class was decided before class, depending on their perception of a number of personal, social and educational antecedents of engagement. (3) Distinguishing engagement from disengagement appeared to be difficult for teachers, because the intention behind student behaviour was not always identifiable.DiscussionThis study adds to the literature by illuminating the dynamic process of student engagement and explaining the difficulty of recognising and influencing this process in practice. Based on the importance of discerning the intentions behind student behaviour, we advise teachers to use their observations of student (dis)engagement to initiate interaction with students with open and inviting prompts. This can help teachers to (re-)engage students in their classrooms.

For over a century, stability of spatial context across related episodes has been considered a source of memory interference, impairing memory retrieval. However, contemporary memory integration theory generates a diametrically opposite prediction. Here, we aimed to resolve this discrepancy by manipulating local context similarity across temporally disparate but related episodes, and testing the direction and underlying mechanisms of memory change. A series of experiments show that contextual stability produces memory integration and marked reciprocal strengthening. Variable context, conversely, seemed to result in competition such that new memories become enhanced at the expense of original memories. Interestingly, these patterns were virtually inverted in an additional experiment where context was reinstated during recall. These observations (i) identify contextual similarity across original and new memories as an important determinant in the volatility of memory, (ii) present a challenge to classic and modern theories on episodic memory change, and (iii) indicate that sensitivity of context-induced memory changes to retrieval conditions may reconcile paradoxical predictions of interference and integration theory.

© 2020 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.Introduction: For Small-Group Active Learning (SMAL) to be effective, students need to engage meaningfully in learning activities to construct their knowledge. Teachers can have difficulty engaging their students in this process. To improve engagement, we aimed to identify the diversity in medical students’ appreciation of SMAL, using the concepts of epistemic beliefs and approaches to learning. Method: Q-methodology is a mixed-method research design used for the systematic study of subjectivity. We developed a set of 54 statements on active learning methods. In individual interviews, first-year medical students rank ordered their agreement with these statements and explained their reasons. Data were analyzed using a by-person factor analysis to group participants with shared viewpoints. Results: A four-factor solution (i.e. profiles) fit the data collected from 52 students best and explained 52% of the variance. Each profile describes a shared viewpoint on SMAL. We characterized the profiles as ‘understanding-oriented’, ‘assessment-oriented’, ‘group-oriented’, and ‘practice-oriented’. Discussion: The four profiles describe how and why students differ in their appreciation of SMAL. Teachers can use the profiles to make better-informed decisions when designing and teaching their SMAL classes, by relating to students’ epistemic beliefs, and approaches to learning. This may improve student motivation and engagement for SMAL.

BACKGROUND: Recently, we showed that twice weekly sessions of cognitive-behavioral therapy (CBT) and interpersonal psychotherapy (IPT) for depression lead to better and faster treatment outcomes compared to once weekly sessions (Bruijniks et al., 2020). The present study investigated which pathways of change may account for the effects of different session frequencies.METHOD: The sample consisted of 200 patients who were randomized to CBT weekly, CBT twice weekly, IPT weekly, or IPT twice weekly. Outcome and therapy processes were measured at baseline, two weeks and monthly up to month 6 after the start of treatment. Latent change score models investigated temporal relations between change in therapy processes and change in depression and tested whether change in the therapy processes mediated the effect of session frequency on change in depression.RESULTS: IPT skills mediated the relation between session frequency and change in depression. A decrease in depression was related to subsequent improvement in CBT skills and subsequent decrease in motivation for therapy.CONCLUSION: The development of IPT skills may explain why a twice weekly higher session frequency is more effective in reducing depression compared to a once-weekly session frequency. Future studies should disentangle the causal effects of therapy process change throughout the course of therapy.

Building knowledge schemas that organize information and guide future learning is of great importance in everyday life. Such knowledge building is suggested to occur through reinstatement of prior knowledge during new learning, yielding integration of new with old memories supported by the medial prefrontal cortex (mPFC) and medial temporal lobe (MTL). Congruency with prior knowledge is also known to enhance subsequent memory. Yet, how reactivation and congruency interact to optimize memory integration is unknown. To investigate this question, we used an adapted AB-AC inference paradigm in combination with functional Magnetic Resonance Imaging (fMRI). Participants first studied an AB-association followed by an AC-association, so B (a scene) and C (an object) were indirectly linked through A (a pseudoword). BC-associations were either congruent or incongruent with prior knowledge (e.g. bathduck or hammer in a bathroom), and participants reported subjective B-reactivation strength while learning AC. Behaviorally, both congruency and reactivation enhanced memory integration. In the brain, these behavioral effects related to univariate and multivariate parametric effects in the MTL, mPFC, and Parahippocampal Place Area (PPA). Moreover, mPFC exhibited larger PPA-connectivity for more congruent associations. These outcomes provide insights into the neural mechanisms underlying memory enhancement, which has value for educational learning.

The notion that the brain achieves visual word recognition by encoding the relative positions of letters with open-bigram representations (e.g., ‘h-e’, ‘h-r’ and ‘e-r’ driving recognition of ‘her’) has been successful in accounting for many behaviors and phenomena. However, one characteristic of open-bigrams has remained unexplored: How is the activation of a bigram modulated by the distance between its constituents in the visual field? On the one hand, contiguous letters (e.g., ‘at’ in ‘father’) may allow for a clearer percept of the bigram. On the other hand, an increasing distance between letters (e.g., ‘ae’ in ‘father’) should create more certainty about their relative positions, which is precisely what the bigram is meant to convey. This matter was investigated with two experiments in which participants indicated whether target pairs of letters occurred in random letter strings. They were instructed that letter order mattered (i.e., ‘a-b’ does not occur in ‘kbac’), while letter contiguity did not (i.e., ‘a-b’ occurs in ‘akcb’). Controlling for crowding and eccentricity, bigrams were recognized faster upon decreasing the letter distance. However, when switching the target letter order (meaning the string should be met by a ‘no’ response), shorter letter distances yielded slower responses and more false positives. Neither relative position-coding models nor absolute position-coding models accommodate both these patterns at once. We discuss how a complete account of our effects may instead combine elements from both model types.

Contains fulltext : 236748.pdf (Publisher’s version ) (Open Access) Objectives: The goal of the present study was to identify the role of the medial temporal lobe (MTL) in the detection and later processing of novelty. Methods: Twenty-one epilepsy patients with unilateral MTL resection (10 left-sided; 11 right-sided) and 26 matched healthy controls performed an adapted visual novelty oddball task. In this task two streams of stimuli were presented on the left and right of fixation while the patients’ electroencephalogram was measured. The participants had to respond to infrequent target stimuli, while ignoring frequent standard, and infrequent novel stimuli that were presented to the left or right, appearing either contra- or ipsilateral to the patients’ resections. Results: Novelty detection, as indexed by the N2 ERP component elicited by novels, was reduced by the MTL resections, as evidenced by a smaller N2 for patients than healthy controls. Later processing of novels, as indexed by the novelty P3 ERP component, was reduced for novels presented contra- versus ipsilateral to the resected side. Moreover, at a frontal electrode site, the N2-P3 complex showed reduced novelty processing in patients with MTL resections compared to healthy controls. The ERP differences were specific for the novel stimuli, as target processing, as indexed by the P3b, was unaffected in the patients: No P3b differences were found between targets presented ipsi- or contralaterally to the resected side, nor between patients and healthy controls. Conclusions: The current results suggest that MTL structures play a role in novelty processing. In contrast, target processing was unaffected by MTL resections. 11 p.

According to several computational models, novel items can create a learning mode with dynamics favorable to new learning, and not to memory retrieval. In line with that idea, a new item in a recognition test has been found to create a bias toward calling subsequent items new as well. Here, we tested whether this bias, which we termed the afterglow effect, is indeed caused by a general learning mode, or is caused by perceptual overlap between preceding and current items. In two experiments, we show that a preceding recognition judgment biases the current one, but only if the preceding and current items are of the same perceptual category. In contrast, we did not find strong bias effects from perceptually novel fractal images, as would be predicted if novel items induce a learning mode that then biases recognition judgments. We conclude that the afterglow effect is more likely to reflect perceptual phenomena than a learning mode. We suggest how this can be reconciled with what is known about familiarity at the neural level.

During reading, word recognition speed is influenced by the amount of orthographic overlap with surrounding words. The nature of this phenomenon is not understood: some theories attribute it to low-level visual operations (i.e., parafoveal feature detectors influencing foveal letter detectors), whereas other theories assume that orthographic processing (i.e., letter position coding and word activation) occurs across multiple words in parallel. To arbitrate between these theories, we used electroencephalography to reveal the time course of orthographic spatial integration in a lexical decision task. Foveal target words were flanked on each side by parafoveal words, manipulated across three conditions: repetition flankers (e.g. rock rock rock), unrelated flankers (step rock step) and a no-flanker condition. Linear mixed-effect models were constructed to analyze EEG data on a trial-by-trial basis. Word recognition was worse in the unrelated flanker condition than in the repetition and no-flanker conditions. This behavioral pattern was accompanied by increased negativity in the N250 and N400 windows, associated with the activation of sub-lexical and lexico-semantic representations, respectively. Crucially, the absence of effects prior to 200 ms post-stimulus onset provides evidence against the involvement of low-level visual processes. We conclude that orthographic spatial integration is driven by parallel processing of multiple words, which leads to the activation of a larger set of sub-lexical nodes and more difficult processing at the lexical level when those words are orthographically unrelated., Highlights • Words are recognized faster when they share many letters with surrounding words. • EEG measurements suggest that this effect unfolds 200 ms after stimulus onset. • The locus of effects contradicts the involvement of low-level visual processing. • Instead, the phenomenon appears to be driven by parallel orthographic processing.

Background Teamwork is essential in healthcare, but team performance tends to deteriorate in stressful situations. Further development of training and education for healthcare teams requires a more complete understanding of team performance in stressful situations. We wanted to learn from others, by looking beyond the field of medicine, aiming to learn about a) sources of stress, b) effects of stress on team performance and c) concepts on dealing with stress. Methods A scoping literature review was undertaken. The three largest interdisciplinary databases outside of healthcare, Scopus, Web of Science and PsycINFO, were searched for articles published in English between 2008 and 2020. Eligible articles focused on team performance in stressful situations with outcome measures at a team level. Studies were selected, and data were extracted and analysed by at least two researchers. Results In total, 15 articles were included in the review (4 non-comparative, 6 multi- or mixed methods, 5 experimental studies). Three sources of stress were identified: performance pressure, role pressure and time pressure. Potential effects of stress on the team were: a narrow focus on task execution, unclear responsibilities within the team and diminished understanding of the situation. Communication, shared knowledge and situational awareness were identified as potentially helpful team processes. Cross training was suggested as a promising intervention to develop a shared mental model within a team. Conclusion Stress can have a significant impact on team performance. Developing strategies to prevent and manage stress and its impact has the potential to significantly increase performance of teams in stressful situations. Further research into the development and use of team cognition in stress in healthcare teams is needed, in order to be able to integrate this ‘team brain’ in training and education with the specific goal of preparing professionals for team performance in stressful situations.

International audience; When reading, orthographic information is extracted not only from the word the reader is looking at, but also from adjacent words in the parafovea. Here we examined, using the recently introduced OB1-reader computational model, how orthographic information can be processed in parallel across multiple words and how orthographic information can be integrated across time and space. Although OB1-reader is a model of text reading, here we used it to simulate single-word recognition experiments in which parallel processing has been shown to play a role by manipulating the surrounding context in flanker and priming paradigms. In flanker paradigms, observers recognize a central word flanked by other letter strings located left and right of the target and separated from the target by a space. The model successfully accounts for the finding that such flankers can aid word recognition when they contain bigrams of the target word, independent of where those flankers are in the visual field. In priming experiments, in which the target word is preceded by a masked prime, the model accounts for the finding that priming occurs independent of whether the prime and target word are in the same location or not. Crucial to these successes is the key role that spatial attention plays within OB1-reader, as it allows the model to receive visual input from multiple locations in parallel, while limiting the kinds of errors that can potentially occur under such spatial pooling of orthographic information.

Background The COVID-19 pandemic induced many governments to close schools for months. Evidence so far suggests that learning has suffered as a result. Here, it is investigated whether forms of computer-assisted learning mitigated the decrements in learning observed during the lockdown. Method Performance of 53,656 primary school students who used adaptive practicing software for mathematics was compared to performance of similar students in the preceding year. Results During the lockdown progress was faster than it had been the year before, contradicting results reported so far. These enhanced gains were correlated with increased use, and remained after the lockdown ended. This was the case for all grades but more so for lower grades and for weak students, but less so for students in schools with disadvantaged populations. Conclusions These results suggest that adaptive practicing software may mitigate, or even reverse, the negative effects of school closures on mathematics learning.

Attention during visual search is thought to be guided by an active visual working memory (VWM) representation of the search target. We tested the hypothesis that a VWM representation used for searching a target among competing information (a “search template”) is distinct from VWM representations used for simple recognition tasks, without competition. We analyzed EEG from 20 human participants while they performed three different VWM-based visual detection tasks. All tasks started with identical lateralized VWM cues, but differed with respect to the presence and nature of competing distractors during the target display at test, where participants performed a simple recognition task without distractors, or visual search in pop-out (distinct) and serial (non-distinct) search displays. Performance was worst for non-distinct search, and best for simple recognition. During the one second delay period between cue and test, we observed robust suppression of EEG dynamics in the alpha (8–14 Hz) band over parieto-occipital sites contralateral to the relevant VWM item, both in terms of local power as well as interregional phase synchrony within a posterior-parietal network. Importantly, these lateralization dynamics were more strongly expressed prior to search compared to simple recognition. Furthermore, before the VWM cue, alpha phase synchrony between prefrontal and mid-posterior-parietal sites was strongest for non-distinct search, reflecting enhanced anticipatory control prior to VWM encoding. Directional connectivity analyses confirmed this effect to be in an anterior-to-posterior direction. Together, these results provide evidence for frontally mediated top-down control of VWM in preparation of visual search.

Rich contextual and semantic information can be extracted from only a brief presentation of a natural scene. This is presumed to be activated quickly enough to guide initial eye movements into a scene. However, early, short-latency eye movements in natural scenes have been shown to be dependent on the salience distribution across the image (Anderson, Ort, Kruijne, Meeter, & Donk, 2015). In the present work, we manipulated the salience distribution across a natural scene by changing the global contrast. We showed participants a brief real or nonsense preview of the scene and examined the time-course of eye movement guidance. A real preview decreased the latency and increased the amplitude of initial saccades into the image, suggesting that the preview allowed observers to obtain additional contextual information that would otherwise not be available. However, the preview did not completely override the initial tendency for short-latency saccades to be guided by the underlying salience distribution of the image. We discuss these findings in the context of oculomotor selection based on the integration of contextual information and low-level features in a natural scene.

Selective attention plays a prominent role in prioritizing information in working memory (WM), improving performance for attended representations. However, it remains unclear whether unattended WM representations suffer from information loss. Here we tested the hypothesis that within WM, selectively attending to an item and stopping storing other items are independent mechanisms. We recorded EEG while participants performed a WM recall task in which the item most likely to be tested was cued retrospectively during retention. By manipulating retro-cue reliability (i.e., the ratio of valid to invalid cue trials), we varied the incentive to retain non-cued items. Storage and selective attention in WM were measured during the retention interval by contralateral delay activity (CDA) and contralateral alpha power suppression, respectively. Soon after highly reliable cues, the cued item was attended, and non-cued items suffered information loss. However, for less reliable cues, initially the cued item was attended, but unattended items were kept in WM. Later during the delay, previously unattended items suffered information loss despite now attention being reallocated to their locations, presumably to strengthen their weakening traces. These results show that storage and attention in WM are distinct processes that can behave differently depending on the relative importance of representations.

In a warned reaction time task, the warning stimulus (S1) initiates a process of temporal preparation, which promotes a speeded response to the impending target stimulus (S2). According to the multiple trace theory of temporal preparation (MTP), participants learn the timing of S2 by storing a memory trace on each trial, which contains a temporal profile of the events on that trial. On each new trial, S1 serves as a retrieval cue that implicitly and associatively activates memory traces created on earlier trials, which jointly drive temporal preparation for S2. The idea that S1 assumes this role as a retrieval cue was tested across eight experiments, in which two different S1s were associated with two different distributions of S1-S2 intervals: one with predominantly short and one with predominantly long intervals. Experiments differed regarding the S1 features that made up a pair, ranging from highly distinct (e.g., tone and flash) to more similar (e.g., red and green flash) and verbal (i.e., “short” vs “long”). Exclusively for pairs of highly distinct S1s, the results showed that the S1 cue modified temporal preparation, even in participants who showed no awareness of the contingency. This cueing effect persisted in a subsequent transfer phase, in which the contingency between S1 and the timing of S2 was broken – a fact participants were informed of in advance. Together, these findings support the role of S1 as an implicit retrieval cue, consistent with MTP.

Although many of our perceptual biases stem from long-term, repeated exposure, current theories of visual search assume a central role for visual working memory (VWM) in guiding attention to target information. Crucially, whether a VWM representation guides attention depends on the relative priority that the memory has within VWM. Here, in a combined visual search/VWM task, we used attentional guidance by irrelevant memories to measure how long a target representation remains prioritized in VWM when observers repeatedly search for the same target. Irrelevant memories started guiding attention already when the target was repeated once, indicating that the target representation rapidly lost priority within VWM as it moved to long-term memory. By showing that training can lead to interference from irrelevant memories, the findings resolve a long-standing paradox on why VWM appears central to, yet at the same time not sufficient nor necessary for attentional guidance.

Visual attention is strongly affected by the past: both by recent experience and by long-term regularities in the environment that are encoded in and retrieved from memory. In visual search, intertrial repetition of targets causes speeded response times (short-term priming). Similarly, targets that are presented more often than others may facilitate search, even long after it is no longer present (long-term priming). In this study, we investigate whether such short-term priming and long-term priming depend on dissociable mechanisms. By recording eye movements while participants searched for one of two conjunction targets, we explored at what stages of visual search different forms of priming manifest. We found both long- and short- term priming effects. Long-term priming persisted long after the bias was present, and was again found even in participants who were unaware of a color bias. Short- and long-term priming affected the same stage of the task; both biased eye movements towards targets with the primed color, already starting with the first eye movement. Neither form of priming affected the response phase of a trial, but response repetition did. The results strongly suggest that both long- and short-term memory can implicitly modulate feedforward visual processing. Electronic Supplementary Material The online version of this article (doi:10.3758/s13414-015-1021-3) contains supplementary material, which is available to authorized users.

Positive mood ameliorates several cognitive processes: It can enhance cognitive control, increase flexibility, and promote variety seeking in decision making. These effects of positive mood have been suggested to depend on frontostriatal dopamine, which is also associated with the detection of novelty. This suggests that positive mood could also affect novelty detection. In the present study, children and adults saw either a happy or a neutral movie to induce a positive or neutral mood. After that, they were shown novel and familiar images. On some trials a beep was presented over headphones either at the same time as the image or at a 200-ms stimulus onset asynchrony (SOA), and the task of the participant was to detect these auditory targets. Children were slower in responding than adults. Positive mood, however, speeded responses, especially in children, and induced facilitatory effects of novelty. These effects were consistent with increased arousal. Although effects of novelty were more consistent with an attentional response, in children who had watched a happy movie the novel images evoked a more liberal response criterion, suggestive of increased arousal. This suggests that mood and novelty may affect response behaviour stronger in children than in adults.

Our brains are highly responsive to novelty. However, how novelty is processed in the brain, and what neurotransmitter systems play a role therein, remains elusive. Here, we systematically review studies on human participants that have looked at the neuromodulatory basis of novelty detection and processing. While theoretical models and studies on nonhuman animals have pointed to a role of the dopaminergic, cholinergic, noradrenergic and serotonergic systems, the human literature has focused almost exclusively on the first two. Dopamine was found to affect electrophysiological responses to novelty early in time after stimulus presentation, but evidence on its effects on later processing was found to be contradictory: While neuropharmacological studies mostly yielded null effects, gene studies did point to an important role for dopamine. Acetylcholine seems to dampen novelty signals in the medial temporal lobe, but boost them in frontal cortex. Findings on 5-HT (serotonin) were found to be mostly contradictory. Two large gaps were identified in the literature. First, few studies have looked at neuromodulatory influences on behavioral effects of novelty. Second, no study has looked at the involvement of the noradrenergic system in novelty processing.

Research has suggested that the word recognition process is influenced by the integration of orthographic information across words. The precise nature of this integration process may vary, however, depending on whether words are in temporal or spatial proximity. Here we present a lexical decision experiment, designed to compare temporal and spatial integration processes more directly. Masked priming was used to reveal effects of temporal integration, while the flanker paradigm was used to reveal effects of spatial integration. Primes/flankers were high-frequency orthographic neighbors of the target (blue-blur) or unrelated control words (head-blur). We replicated prior observations of inhibition in trials where the neighbor was used as a masked prime, while facilitation was observed in trials where the neighbor was presented as flanker. We conclude that sub-lexical orthographic information is integrated both temporally and spatially, but that spatial information is used to segregate lexical representations activated by spatially distinct sources.

Fulfilled predictions lead to neural suppression akin to repetition suppression, but it is currently unclear if such effects generalize to broader stimulus categories in the absence of exact expectations. In particular, does expecting novelty alter the way novel stimuli are processed? In the present study, the effects of expectations on novelty processing were investigated using event-related potentials, while controlling for the effect of repetition. Sequences of five stimuli were presented in a continuous way, such that the last stimulus of a 5-stimulus sequence was followed by the first stimulus of a new 5-stimulus sequence without interruption. The 5-stimulus sequence was predictable: the first three stimuli were preceded by a cue indicating that the next stimulus was likely to be a standard stimulus, and the last two by a cue indicating that the next stimulus was likely to be novel. On some trials a cue typically predicting a standard was in fact followed by an unexpected novel stimulus. This design allowed to investigate the independent effects of (violated) expectations and repetition on novelty processing. The initial detection of expected novels was enhanced compared to unexpected novels, as indexed by a larger anterior N2. In contrast, the orienting response, as reflected by a novelty P3, was reduced for expected compared to unexpected novels. Although the novel stimuli were never repeated themselves, they could be presented after one another in the sequence. Such a category repetition affected the processing of novelty, as evidenced by an enhanced anterior N2, and a reduced novelty P3 for novels preceded by other novels. Taken together, the current study shows that novelty processing is influenced by expectations.

It is often thought that novelty benefits memory formation. However, support for this idea mostly comes from paradigms that are open to alternative explanations. In the present study we manipulated novelty in a word-learning task through task-irrelevant background images. These background images were either standard (presented repeatedly), or novel (presented only once). Two types of background images were used: Landscape pictures and fractals. EEG was also recorded during encoding. Contrary to the idea that novelty aids memory formation, memory performance was not affected by the novelty of the background. In the evoked response potentials, we found evidence of distracting effects of novelty: both the N1 and P3b components were smaller to words studied with novel backgrounds, and the amplitude of the N2b component correlated negatively with subsequent retrieval. We conclude that although evidence from other studies does suggest benefits on a longer time scale, novelty has no instantaneous benefits for learning.

Memory affects visual search, as is particularly evident from findings that when target features are repeated from one trial to the next, selection is faster. Two views have emerged on the nature of the memory representations and mechanisms that cause these intertrial priming effects: independent feature weighting versus episodic retrieval of previous trials. Previous research has attempted to disentangle these views focusing on short term effects. Here, we illustrate that the episodic retrieval models make the unique prediction of long-term priming: biasing one target type will result in priming of this target type for a much longer time, well after the bias has disappeared. We demonstrate that such long-term priming is indeed found for the visual feature of color, but only in conjunction search and not in singleton search. Two follow-up experiments showed that it was the kind of search (conjunction versus singleton) and not the difficulty, that determined whether long-term priming occurred. Long term priming persisted unaltered for at least 200 trials, and could not be explained as the result of explicit strategy. We propose that episodic memory may affect search more consistently than previously thought, and that the mechanisms for intertrial priming may be qualitatively different for singleton and conjunction search. Electronic supplementary material The online version of this article (doi:10.3758/s13414-015-0860-2) contains supplementary material, which is available to authorized users.

Introduction: Bipolar disorder (BD) is a psychiatric disorder accompanied by deficits in declarative memory. Given the importance of the hippocampus in declarative memory, it is not surprising that BD patients have been reported to show hippocampal abnormalities. Objectives: Review evidence about structural and functional hippocampal abnormalities in BD. Methods: Systematic review of studies comparing BD patients and healthy controls with respect to hippocampal structure or function. Results: Twenty-five studies were included, together involving 1043 patients, 21 of which compared patients to controls. Decrease in hippocampal volume was found in four of 18 studies using adult samples, and two of three samples using adolescents. Four studies revealed localized hippocampal deficits. Meta-analysis revealed a significant but small effect with lower hippocampal volumes when comparing all BD patients with controls. Lithium treatment was associated with larger hippocampal volumes across studies. The three functional studies yielded contradictory evidence. Limitations: Studies were only cross-sectional in nature and all used MRI or fMRI to investigate hippocampal volume or function. Heterogeneous patients groups and different methodologies for hippocampal segmentation, may have contributed to difficulties when comparing the different studies. Conclusions: There seems to be a small reduction in hippocampal volume in BD, which perhaps is more pronounced in early-onset BD and is counteracted by a neuroprotective effect of lithium treatment. However, how these structural abnormalities relate to functional deficits is largely unclear. Given the few functional neuroimaging studies and given the lack of congruence in these results, further investigation of especially hippocampal function in BD is recommended. (C) 2014 Elsevier B.V. All rights reserved.

Our visual brain makes use of recent experience to interact with the visual world, and efficiently select relevant information. This is exemplified by speeded search when target- and distractor features repeat across trials versus when they switch, a phenomenon referred to as intertrial priming. Here, we present fAIM, a computational model that demonstrates how priming can be explained by a simple feature-weighting mechanism integrated into an established model of bottom-up vision. In fAIM, such modulations in feature gains are widespread and not just restricted to one or a few features. Consequentially, priming effects result from the overall tuning of visual features to the task at hand. Such tuning allows the model to reproduce priming for different types of stimuli, including for typical stimulus dimensions such as ‘color’ and for less obvious dimensions such as ‘spikiness’ of shapes. Moreover, the model explains some puzzling findings from the literature: it shows how priming can be found for target-distractor stimulus relations rather than for their absolute stimulus values per se, without an explicit representation of relations. Similarly, it simulates effects that have been taken to reflect a modulation of priming by an observers’ goals—without any representation of goals in the model. We conclude that priming is best considered as a consequence of a general adaptation of the brain to visual input, and not as a peculiarity of visual search.

Temporal preparation has been investigated extensively by manipulating the foreperiod, the interval between a warning stimulus and target stimulus requiring a speeded response. Although such research has revealed many effects of both the duration and distribution of foreperiods on reaction times, the underlying cognitive mechanism is still largely unknown. Here, we test a recent proposal that temporal preparation is driven by the retrieval of memory traces of past experiences from long-term memory rather than by knowledge about upcoming events. Two groups of participants received different foreperiod distributions in an acquisition phase, which was followed a week later by a transfer phase, in which both groups received the same distribution of foreperiods. We found that the effects of the different foreperiod distributions presented in the acquisition phase were still apparent a week later during the transfer phase, as the reaction time patterns of both groups reflected the old distributions. This occurred even though both groups were provided with full information about the change in the distribution of foreperiods at the start of the transfer phase. These findings provide compelling evidence that long-term memory plays an important role in temporal preparation.

The hazard function describes the conditional probability that an event will occur at a given moment, given that it has not yet occurred. In warned reaction time tasks, it is a classical finding that the response to a target stimulus is faster as its hazard is higher, which has led to the widespread belief that hazard somehow drives temporal preparation. Alternatively, recent cognitive theories propose that temporal preparation is driven by memory traces of earlier timing experiences. To distinguish between these views, we presented different groups of participants with different distributions of foreperiods between temporal cues and target stimuli. Three experiments revealed clear transfer effects of this manipulation in a test phase where all participants received, after explicit instruction, the same uniform distribution. These findings demonstrate that temporal preparation is driven by past experience, not by current hazard. (PsycINFO Database Record

International audience; A hotly debated issue in reading research concerns the extent to which readers process parafoveal words, and how parafoveal information might influence foveal word recognition. We investigated syntactic word processing both in sentence reading and in reading isolated foveal words when these were flanked by parafoveal words. In Experiment 1 we found a syntactic parafoveal preview benefit in sentence reading, meaning that fixation durations on target words were decreased when there was a syntactically congruent preview word at the target location (n) during the fixation on the pre-target (n-1). In Experiment 2 we used a flanker paradigm in which participants had to classify foveal target words as either noun or verb, when those targets were flanked by syntactically congruent or incongruent words (stimulus on-time 170 ms). Lower response times and error rates in the congruent condition suggested that higher-order (syntactic) information can be integrated across foveal and parafoveal words. Although higher-order parafoveal-on-foveal effects have been elusive in sentence reading, results from our flanker paradigm show that the reading system can extract higher-order information from multiple words in a single glance. We propose a model of reading to account for the present findings.

Parkinson[U+05F3]s disease (PD) is characterized by a degeneration of nigrostriatal dopaminergic cells, resulting in dopamine depletion. This depletion is counteracted through dopamine replacement therapy (DRT). Dopamine has been suggested to affect novelty processing and memory, which suggests that these processes are also implicated in PD and that DRT could affect them. Objective: To investigate word learning and novelty processing in patients with PD as indexed by the P2 and P3 event-related potential components, and the role of DRT in these processes. Methods: 21 patients with PD and 21 matched healthy controls were included. Patients with PD were tested on and off DRT in two sessions in a counterbalanced design, and healthy controls were tested twice without intervention. Electroencephalogram (EEG) was measured while participants performed a word learning Von Restorff task. Results: Healthy controls showed the typical Von Restorff effect, with better memory for words that were presented in novel fonts, than for words presented in standard font. Surprisingly, this effect was reversed in the patients with PD. In line with the behavioral findings, the P3 was larger for novel than for standard font words in healthy controls, but not in patients with PD. For both groups the P2 and P3 event-related components were larger for recalled versus forgotten words. DRT did not affect these processes. Conclusions: Learning of novel information is compromised in patients with PD. Likewise, the P2 and P3 components that predict successful memory encoding are reduced in PD patients. This was true both on and off DRT, suggesting that these findings reflect abnormalities in learning and memory in PD that are not resolved by dopaminergic medication. © 2014 Elsevier Ltd.

Novel stimuli are detected and evaluated quickly, suggesting that processing them is a priority for the brain. In the present study, the effects of attention on this early visual novelty processing were investigated in two experiments using the event-related potential (ERP) technique. In the first experiment, participants performed two tasks that varied in the amount of attention available for novel stimuli. In the Visual Oddball task, participants responded to an infrequent target presented among standard and novel stimuli. In the Working Memory task, participants saw the same stimuli, but they could ignore them. Instead, participants had to keep six letters in working memory and report one of these letters at the end of the trial; attention was thus maximally allocated away from the visual oddball stimuli. In line with attention being fully occupied in the Working Memory task, the P3a to the visual oddball stimuli was smaller in the Working Memory than in the Visual Oddball task. In contrast, the anterior N2 component to task-irrelevant stimuli was enhanced in the Working Memory task. These findings suggest that the initial detection of novel stimuli is enhanced (large anterior N2) when few attentional resources are available, which is inconsistent with earlier findings that if anything, the N2 is enhanced by attention. In a second experiment, a condition was added in which working memory load was low, but visual oddball stimuli were task-irrelevant. Results from this experiment showed that while the reduction in P3a amplitude was due to task irrelevance, the enhanced anterior N2 was linked to a high working memory load. This suggests that novelty detection is enhanced when attention is otherwise engaged.

Visual search requires the maintenance of a search template in visual working memory in order to guide attention towards the target. This raises the question whether a search template is essentially the same as a visual working memory representation used in tasks that do not require attentional guidance, or whether it is a qualitatively different representation. Two experiments tested this by comparing electrophysiological markers of visual working memory maintenance between simple recognition and search tasks. For both experiments, responses were less rapid and less accurate in search task than in simple recognition. Nevertheless, the contralateral delay activity (CDA), an index of quantity and quality of visual working memory representations, was equal across tasks. On the other hand, the late positive complex (LPC), which is sensitive to the effort invested in visual working memory maintenance, was greater for the search task than the recognition task. Additionally, when the same target cue was repeated across trials (Experiment 2), the amplitude of visual working memory markers (both CDA and LPC) decreased, demonstrating learning of the target at an equal rate for both tasks. Our results suggest that a search template is qualitatively the same as a representation used for simple recognition, but greater effort is invested in its maintenance. © 2014 Elsevier Ltd.

Over 100,000 verbal and visuospatial immediate and delayed memory tests were presented via the Internet to over 28,000 participants in the age range of 11 to 80. Structural equation modeling pointed to the verbal versus visuospatial dimension as an important factor in individual differences, but not the immediate versus delayed dimension. We found a linear decrease of 1% to 3% per year in overall memory performance past the age of 25. For visuospatial tests, this decrease started at age 18 and was twice as fast as the decrease of verbal memory. There were strong effects of education, with the highest educated group sometimes scoring one full standard deviation above the lowest educated group. Gender effects were small but as expected: women outperformed men on the verbal memory tasks; men outperformed women on the visuospatial tasks. We also found evidence of increasing proneness to false memory with age. Memory for recent news events did not show a decrease with age. © 2012 Elsevier B.V.

Background The inability to store fearful memories into their original encoding context is considered to be an important vulnerability factor for the development of anxiety disorders like posttraumatic stress disorder. Altered memory contextualization most likely involves effects of the stress hormone cortisol, acting via receptors located in the memory neurocircuitry. Cortisol via these receptors induces rapid nongenomic effects followed by slower genomic effects, which are thought to modulate cognitive function in opposite, complementary ways. Here, we targeted these time-dependent effects of cortisol during memory encoding and tested subsequent contextualization of emotional and neutral memories. Methods In a double-blind, placebo-controlled design, 64 men were randomly assigned to one of three groups: 1) received 10 mg hydrocortisone 30 minutes (rapid cortisol effects) before a memory encoding task; 2) received 10 mg hydrocortisone 210 minutes (slow cortisol) before a memory encoding task; or 3) received placebo at both times. During encoding, participants were presented with neutral and emotional words in unique background pictures. Approximately 24 hours later, context dependency of their memories was assessed. Results Recognition data revealed that cortisol's rapid effects impair emotional memory contextualization, while cortisol's slow effects enhance it. Neutral memory contextualization remained unaltered by cortisol, irrespective of the timing of the drug. Conclusions This study shows distinct time-dependent effects of cortisol on the contextualization of specifically emotional memories. The results suggest that rapid effects of cortisol may lead to impaired emotional memory contextualization, while slow effects of cortisol may confer protection against emotional memory generalization. © 2013 Society of Biological Psychiatry.

Adaptive behavior in a changing world requires flexibly adapting one’s rate of learning to the rate of environmental change. Recent studies have examined the computational mechanisms by which various environmental factors determine the impact of new outcomes on existing beliefs (i.e., the ‘learning rate’). However, the brain mechanisms, and in particular the neuromodulators, involved in this process are still largely unknown. The brain-wide neurophysiological effects of the catecholamines norepinephrine and dopamine on stimulus-evoked cortical responses suggest that the catecholamine systems are well positioned to regulate learning about environmental change, but more direct evidence for a role of this system is scant. Here, we report evidence from a study employing pharmacology, scalp electrophysiology and computational modeling (N = 32) that suggests an important role for catecholamines in learning rate regulation. We found that the P3 component of the EEG—an electrophysiological index of outcome-evoked phasic catecholamine release in the cortex—predicted learning rate, and formally mediated the effect of prediction-error magnitude on learning rate. P3 amplitude also mediated the effects of two computational variables—capturing the unexpectedness of an outcome and the uncertainty of a preexisting belief—on learning rate. Furthermore, a pharmacological manipulation of catecholamine activity affected learning rate following unanticipated task changes, in a way that depended on participants’ baseline learning rate. Our findings provide converging evidence for a causal role of the human catecholamine systems in learning-rate regulation as a function of environmental change., Author Summary Belief updating in response to changes in the environment is crucial for adaptive behavior. We examined the role of the human catecholamine (norepinephrine and dopamine) systems in this process, using a combination of pharmacology, scalp electrophysiology and computational modeling. We found that the P3 component of the event-related potential—an electrophysiological index of phasic catecholamine release in the cortex—predicted learning rate and mediated the effect of prediction-error magnitude on learning rate. Furthermore, a pharmacological manipulation of catecholamine activity affected learning rate following unanticipated task changes, in a way that depended on participants’ natural learning rate. These findings may reflect the catecholaminergic regulation of belief updating following environmental change.

Studies on intertrial priming have shown that in visual search experiments, the preceding trial automatically affects search performance: facilitating it when the target features repeat and giving rise to switch costs when they change-so-called (short-term) intertrial priming. These effects also occur at longer time scales: When 1 of 2 possible target colors is more frequent during an experiment block, this results in a prolonged and persistent facilitation for the color that was biased, long after the frequency bias is gone-so-called long-term priming. In this study, we explore the robustness of such long-term priming. In Experiment 1, participants were fully informed of the bias and instructed to prioritize the other unbiased color. Despite these instructions, long-term priming of the biased color persisted in this block, suggesting that guidance by long-term priming is an implicit effect. In Experiment 2, long-term priming was built up in 1 experimental session and was then assessed in a second session a week later. Long-term priming persisted across this week, emphasizing that long-term priming is truly a phenomenon of long-term memory. The results support the view that priming results from the automatic and implicit retrieval of memory traces of past trials. (PsycINFO Database Record

Objective: Although electroconvulsive therapy (ECT) is generally considered effective against depression, it remains controversial because of its association with retrograde memory loss. Here, we assessed memory after ECT in circumstances most likely to yield strong retrograde amnesia. Method: A cohort of patients undergoing ECT for major depression was tested before and after ECT, and again at 3-months follow-up. Included were 21 patients scheduled to undergo bilateral ECT for severe major depression and 135 controls matched for gender, age, education, and media consumption. Two memory tests were used: a verbal learning test to assess anterograde memory function, and a remote memory test that assessed memory for news during the course of one year. Results: Before ECT the patients' scores were lower than those of controls. They were lower again after treatment, suggesting retrograde amnesia. At follow-up, however, memory for events before treatment had returned to the pre-ECT level. Memory for events in the months after treatment was as good as that of controls. Limitations: The sample size in this study was not large. Moreover, memory impairment did not correlate with level of depression, which may be due to restriction of range. Conclusions: Our results are consistent with the possibility that ECT as currently practiced does not cause significant lasting retrograde amnesia, but that amnesia is mostly temporary and related to the period of impairment immediately following ECT. (C) 2011 Elsevier B.V. All rights reserved.

Visual search for a unique stimulus is often faster when the feature defining this target is repeated. Recent research has related this feature priming to ambiguity: priming effects appear stronger when the search target is perceptually ambiguous, as when the search array contains a salient distractor. Here we link the ambiguity that underlies feature priming to ambiguity in neural representation caused by the receptive field organization of visual cortex. We show that as the magnitude of neural activity involved in resolving perceptual ambiguity in early stages of visual cortex increases-indexed in posterior aspects of the N2pc component of the visual-event related potential-so does the behavioral feature priming effect. When ambiguity resolution mechanisms act strongly and the target repeats, target processing is facilitated. When these mechanisms act strongly, but the features that have previously defined the target come to characterize the distractor, attention is captured to the distractor location. These results suggest that ambiguity and the attentional mechanisms responsible for resolving it play central roles in feature priming. © 2010 Elsevier B.V.

We present a model of the eye movement system in which the programming of an eye movement is the result of the competitive integration of information in the superior colliculi (SC). This brain area receives input from occipital cortex, the frontal eye fields, and the dorsolateral prefrontal cortex, on the basis of which it computes the location of the next saccadic target. Two critical assumptions in the model are that cortical inputs are not only excitatory, but can also inhibit saccades to specific locations, and that the SC continue to influence the trajectory of a saccade while it is being executed. With these assumptions, we account for many neurophysiological and behavioral findings from eye movement research. Interactions within the saccade map are shown to account for effects of distractors on saccadic reaction time (SRT) and saccade trajectory, including the global effect and oculomotor capture. In addition, the model accounts for express saccades, the gap effect, saccadic reaction times for antisaccades, and recorded responses from neurons in the SC and frontal eye fields in these tasks. © The Author(s) 2010.

Acquired equivalence is a paradigm in which generalization is increased between two superficially dissimilar stimuli (or antecedents) that have previously been associated with similar outcomes (or consequents). Several possible mechanisms have been proposed, including changes in stimulus representations, either in the form of added associations or a change of feature salience. A different way of conceptualizing acquired equivalence is in terms of strategic inference: Confronted with a choice on which it has no evidence, the organism may infer from its history of reinforcement what the best option is, and that inference is observed as acquired equivalence. To test this account, we combined an incremental learning task with an episodic memory test. Drawings of faces were made equivalent through acquired equivalence training, and then paired with words in a list learning paradigm. When participants were asked to recognize specific face-word pairings, they confused faces more often when they had been made equivalent. This suggests that prior acquired equivalence training does influence how memories are coded. We also tested whether this change in coding reflected acquisition of new associations, as suggested by the associative mediation account, or whether stimuli become more similar through a reweighting of stimulus features, as assumed by some categorization theories. Results supported the associative mediation view. We discuss similarities between this view and exemplar theories of categorization performance.

Functional neuroimaging studies of probabilistic category learning in healthy adults report activation of cortical-striatal circuitry. Based on previous findings of normal learning rate concurrent with an overall performance deficit in patients with schizophrenia, we hypothesized that relative to healthy adults, patients with schizophrenia would display preserved caudate nucleus and abnormal prefrontal cortex activation during probabilistic category learning. Forty patients with schizophrenia receiving antipsychotic medication and 25 healthy participants were assessed on interleaved blocks of probabilistic category learning and control tasks while undergoing blood oxygenation level-dependent functional magnetic resonance imaging. In addition to the whole sample of patients with schizophrenia and healthy adults, a subset of patients and healthy adults matched for good learning was also compared. In the whole sample analysis, patients with schizophrenia displayed impaired performance in conjunction with normal learning rate relative to healthy adults. The matched comparison of patients and healthy adults classified as good learners revealed greater caudate and dorsolateral prefrontal cortex activity in the healthy adults and greater activation in a more rostral region of the dorsolateral prefrontal, cingulate, parahippocampal and parietal cortex in patients. These results demonstrate that successful probabilistic category learning can occur in the absence of normal frontal-striatal function. Based on analyses of the patients and healthy adults matched on learning and performance, a minority of patients with schizophrenia achieve successful probabilistic category learning and performance levels through differential activation of a circumscribed neural network which suggests a compensatory mechanism in patients showing successful learning. Copyright © 2009 Society for Neuroscience.

In two masked repetition priming experiments with letter stimuli, the positions of prime and target stimuli were varied horizontally from fixation. Priming effects did not interact with position when prime and target location covaried (Experiment 1A) but diminished with increasing prime eccentricity when targets were always centrally located (Experiment 1B). Two accounts of this pattern of priming effects were proposed that postulate two different mechanisms over and above effects of visual acuity. The integration account postulates degree of separation of prime and target stimuli as the critical factor, and the attentional account postulates spatial attention as the critical factor. The results of Experiment 2, in which prime and target positions were manipulated orthogonally, were in favor of the attentional account. Repetition priming did not vary as a function of whether or not primes and targets appeared at the same location, but target processing was facilitated independently of priming when targets appeared at the same location as primes, especially in the right visual field. Copyright 2008 Psychonomic Society, Inc.

What is the time course of visual attention? Attentional blink studies have found that the 2nd of 2 targets is often missed when presented within about 500 ms from the 1st target, resulting in theories about relatively long-lasting capacity limitations or bottlenecks. Earlier studies, however, reported quite the opposite finding: Attention is transiently enhanced, rather than reduced, for several hundreds of milliseconds after a relevant event. The authors present a general theory, as well as a working computational model, that integrate these findings. There is no central role for capacity limitations or bottlenecks. Central is a rapidly responding gating system (or attentional filter) that seeks to enhance relevant and suppress irrelevant information. When items sufficiently match the target description, they elicit transient excitatory feedback activity (a "boost" function), meant to provide access to working memory. However, in the attentional blink task, the distractor after the target is accidentally boosted, resulting in subsequent strong inhibitory feedback response (a "bounce"), which, in effect, closes the gate to working memory. The theory explains many findings that are problematic for limited-capacity accounts, including a new experiment showing that the attentional blink can be postponed. © 2008 American Psychological Association.

In the present experiment, we investigated whether the memory of a location is affected by the occurrence of an irrelevant visual event. Participants had to memorize the location of a dot. During the retention interval, a task-irrelevant stimulus was presented with abrupt onset somewhere in the visual field. Results showed that the spatial memory representation was affected by the occurrence of the external irrelevant event relative to a control condition in which there was no external event. Specifically, the memorized location was shifted toward the location of the task-irrelevant stimulus. This effect was only present when the onset was close in space to the memory representation. These findings suggest that the "internal" spatial map used for keeping a location in spatial working memory and the "external" spatial map that is affected by exogenous events in the outside world are either the same or tightly linked.

Retrospectively cueing an item retained in visual working memory during maintenance is known to improve its retention. However, studies have provided conflicting results regarding the costs of such retro-cues for the noncued items, leading to different theories on the mechanisms behind visual working memory maintenance and retro-cueing. Here we tested an alternative explanation of the conflicting results regarding retro-cue costs—namely, that they are caused at least partly by differences in retro-cue reliability. We manipulated the ratio of valid-cue trials to invalid-cue trials within blocks. We used a continuous-report procedure that allowed fitting a model that provided recall probability and precision estimates for the memory representations. Reconciling previous contradictory findings, benefits for valid cues were observed in all conditions, but invalid cueing costs were found only when the retro-cue had a high reliability (i.e., was 80 % valid), but not when it had a lower reliability (i.e., 50 % valid). This was found for both the recall probability and the precision of visual working memory representations. Our results suggest that the cognitive mechanisms underlying retro-cue effects are strategically adjusted by participants, depending on the perceived retro-cue reliability.

When one encounters a novel stimulus this sets off a cascade of brain responses, activating several neuromodulatory systems. As a consequence novelty has a wide range of effects on cognition; improving perception and action, increasing motivation, eliciting exploratory behavior, and promoting learning. Here, we review these benefits and how they may arise in the brain. We propose a framework that organizes novelty's effects on brain and cognition into three groups. First, novelty can transiently enhance perception. This effect is proposed to be mediated by novel stimuli activating the amygdala and enhancing early sensory processing. Second, novel stimuli can increase arousal, leading to short-lived effects on action in the first hundreds of milliseconds after presentation. We argue that these effects are related to deviance, rather than to novelty per se, and link them to activation of the locus-coeruleus norepinephrine system. Third, spatial novelty may trigger the dopaminergic mesolimbic system, promoting dopamine release in the hippocampus, having longer-lasting effects, up to tens of minutes, on motivation, reward processing, and learning and memory.

Trial-to-trial feature repetition speeds response times in pop-out visual search tasks. These priming effects are often ascribed to a short-term memory system. Recently, however, it has been reported that a 'build-up' sequence of repetitions could facilitate responses over 16 trials later - well beyond twice the typically reported time course (Vision Research, 2011, 51, 1972-1978). Here, we first report two replication attempts that yielded little to no support for such long-term priming of pop-out. The results instead fell in line with the predictions of a previously proposed computational model that describes priming as short-lived facilitation that decays over approximately eight trials (Vision Research, 2010, 50, 2110-2115). In the second part of this study, we show that these data are consistent with a simple formulation of decay with a single timescale, and that there is no significant priming beyond eight trials.

The "Weather Prediction" task is a widely used task for investigating probabilistic category learning, in which various cues are probabilistically (but not perfectly) predictive of class membership. This means that a given combination of cues sometimes belongs to one class and sometimes to another. Prior studies showed that subjects can improve their performance with training, and that there is considerable individual variation in the strategies subjects use to approach this task. Here, we discuss a recently introduced analysis of probabilistic categorization, which attempts to identify the strategy followed by a participant. Monte Carlo simulations show that the analysis can, indeed, reliably identify such a strategy if it is used, and can identify switches from one strategy to another. Analysis of data from normal young adults shows that the fitted strategy can predict subsequent responses. Moreover, learning is shown to be highly nonlinear in probabilistic categorization. Analysis of performance of patients with dense memory impairments due to hippocampal damage shows that although these patients can change strategies, they are as likely to fall back to an inferior strategy as to move to more optimal ones. ©2006 by Cold Spring Harbor Laboratory Press.

By integrating previous computational models of corticohippocampal function, the authors develop and test a unified theory of the neural substrates of familiarity, recollection, and classical conditioning. This approach integrates models from 2 traditions of hippocampal modeling, those of episodic memory and incremental learning, by drawing on an earlier mathematical model of conditioning, SOP (A. Wagner, 1981). The model describes how a familiarity signal may arise from parahippocampal cortices, giving a novel explanation for the finding that the neural response to a stimulus in these regions decreases with increasing stimulus familiarity. Recollection is ascribed to the hippocampus proper. It is shown how the properties of episodic representations in the neocortex, parahippocampal gyrus, and hippocampus proper may explain phenomena in classical conditioning. The model reproduces the effects of hippocampal, septal, and broad hippocampal region lesions on contextual modulation of classical conditioning, blocking, learned irrelevance, and latent inhibition.