Modal-based attention modulates attentional blink

In the rapid serial visual presentation (RSVP) paradigm, response accuracy for the target decreases when it appears within a short time window (200~500 ms) after the previous target. This phenomenon is termed the attentional blink (AB). Although mechanisms of cross-modal processing that reduce the AB have been documented, researchers have not explored the differences across modal attentional conditions. In the present study, we used the RSVP paradigm to investigate the effect of auditory-driven visual target perceptual enhancement on the AB under modality-specific selective attention (Experiment 1) and bimodal-divided attention (Experiment 2). The results showed that cross-modal attentional enhancement was not moderated by stimulus salience. Moreover, the results also showed that accuracy was higher when the attended sound appeared simultaneously with the target. These results indicated that audiovisual enhancement reduced AB and that stronger attentional enhancement in the bimodal-divided attentional condition led to the disappearance of AB.

What processes are disrupted during the attentional blink? An integrative review of event-related potential research

Reporting the second of two targets is impaired when these appear in close succession, a phenomenon known as the attentional blink (AB). Despite decades of research, what factors limit our ability to process multiple sequentially presented events remains unclear. Specifically, two central issues remain open: does failure to report the second target (T2) reflect a structural limitation in working memory (WM) encoding or a disruption to attentional processes? And is perceptual processing of the stimulus that we fail to report impaired, or only processes that occur after this stimulus is identified? We address these questions by reviewing event-related potential (ERP) studies of the AB, after providing a brief overview of the theoretical landscape relevant to these debates and clarifying key concepts essential for interpreting ERP studies. We show that failure to report the second target is most often associated with disrupted attentional engagement (associated with a smaller and delayed N2pc component). This disruption occurs after early processing of T2 (associated with an intact P1 component), weakens its semantic processing (typically associated with a smaller N400 component), and prevents its encoding into WM (associated with absent P3b). However, failure to encode T2 in WM can occur despite intact attentional engagement and semantic processing. We conclude that the AB phenomenon, which reflects our limited ability to process sequential events, emerges from the disruption of both attentional engagement and WM encoding.

The role of individual differences in attentional blink phenomenon and real-time-strategy game proficiency

The impact of action videogame playing on cognitive functioning is the subject of debate among scientists, with many studies showing superior performance of players relative to non-players on a number of cognitive tasks. Moreover, the exact role of individual differences in the observed effects is still largely unknown. In our Event-Related Potential (ERP) study we investigated whether training in a Real Time Strategy (RTS) video game StarCraft II can influence the ability to deploy visual attention measured by the Attentional Blink (AB) task. We also asked whether individual differences in a psychophysiological response in the AB task predict the effectiveness of the video game training. Forty-three participants (non-players) were recruited to the experiment. Participants were randomly assigned to either experimental (Variable environment) or active control (Fixed environment) group, which differed in the type of training received. Training consisted of 30 h of playing the StarCraft II game. Participants took part in two EEG sessions (pre- and post-training) during which they performed the AB task. Our results indicate that both groups improved their performance in the AB task in the post-training session. What is more, in the experimental group the strength of the amplitude of the P300 ERP component (which is related to a conscious visual perception) in the pre training session appeared to be predictive of the level of achievement in the game. In the case of the active control group in-game behaviour appeared to be predictive of a training-related improvement in the AB task. Our results suggest that differences in the neurophysiological response might be treated as a marker of future success in video game acquisition, especially in a more demanding game environment.

Attentional blink in preverbal infants

Primary cognitive processes, such as spatial attention, are essential to our higher cognitive abilities and develop dramatically in the first year of life. The spatial aspect of infants' working memory is equivalent to that of adults. However, it is unclear whether this is true for the temporal domain. Thus, we investigated the temporal aspect of infants' working memory using an attentionally demanding task by focusing on the attentional blink effect, in which the identification of the second of the two brief targets is impaired when inter-target lags are short. We argue that finding a similar pattern of the attentional blink in preverbal infants and adults indicates that infants can complete the consolidation of the first target into working memory at a similar temporal scale as adults. In this experiment, we presented 7- to 8-month-old infants with rapid serial visual streams at a rate of 100 ms/item, including two female faces as targets, and examined whether they could identify the targets by measuring their preference to novel faces compared to targets. The temporal separation between the two targets was 200 or 800 ms. We found that the infants could identify both targets under the longer lag, but they failed to identify the second target under the shorter lag. The adult experiment using the same temporal separation as in the infant experiment revealed the attentional blink effect. These results suggest that 7- to 8-month-old infants can consolidate two items into working memory by 800 ms but not by 200 ms.

The Sync-Fire/deSync model: Modelling the reactivation of dynamic memories from cortical alpha oscillations

We propose a neural network model to explore how humans can learn and accurately retrieve temporal sequences, such as melodies, movies, or other dynamic content. We identify target memories by their neural oscillatory signatures, as shown in recent human episodic memory paradigms. Our model comprises three plausible components for the binding of temporal content, where each component imposes unique limitations on the encoding and representation of that content. A cortical component actively represents sequences through the disruption of an intrinsically generated alpha rhythm, where a desynchronisation marks information-rich operations as the literature predicts. A binding component converts each event into a discrete index, enabling repetitions through a sparse encoding of events. A timing component - consisting of an oscillatory "ticking clock" made up of hierarchical synfire chains - discretely indexes a moment in time. By encoding the absolute timing between discretised events, we show how one can use cortical desynchronisations to dynamically detect unique temporal signatures as they are reactivated in the brain. We validate this model by simulating a series of events where sequences are uniquely identifiable by analysing phasic information, as several recent EEG/MEG studies have shown. As such, we show how one can encode and retrieve complete episodic memories where the quality of such memories is modulated by the following: alpha gate keepers to content representation; binding limitations that induce a blink in temporal perception; and nested oscillations that provide preferential learning phases in order to temporally sequence events.

Two replications of Raymond, Shapiro, and Arnell (1992), The Attentional Blink

In order to improve the trustworthiness of our science, several new research practices have been suggested, including preregistration, large statistical power, availability of research data and materials, new statistical standards, and the replication of experiments. We conducted a replication project on an original phenomenon that was discovered more than 25 years ago, namely the attentional blink (Raymond, Shapiro, & Arnell, Human Perception and Performance, 18(3), 849-860, 1992), which has been conceptually replicated hundreds of times with major variations. Here, we ran two identical experiments, adopting the new practices and closely reproducing the original experiment. The two experiments were run by different research groups in different countries and laboratories with different participants. Experiment 1 shared remarkable similarities (in magnitude and duration of the effect) with the original study, but also some differences (the overall accuracy of participants, the timing of the effect, and lag-1 sparing). Experts interviewed to evaluate our results stressed the similarities rather than the differences. Experiment 2 replicated nearly identically the results observed in Experiment 1. These findings show that the adoption of new research practices improves the replicability of experimental research and opens the door for a quantitative and direct comparison of the results collected across different laboratories and countries.

Deployment dynamics of hypnotic anger modulation

To understand the role that attention plays in the deployment timeline of hypnotic anger modulation, we composed an Attentional Blink paradigm where the first and second targets were faces, expressing neutral or angry emotions. We then suppressed the salience of angry faces through a "hypnotic numbing" suggestion. We found that hypnotic suggestion only attenuated the emotional salience of the second target (T2). By implementing drift-diffusion decision modelling, we also found that hypnotic suggestion mainly affected decision thresholds. These findings suggest that hypnotic numbing resulted from belated changes in response strategy. Interestingly, a contrast against non-hypnotized participants revealed that the numbing suggestion had the instruction-like feature of incorporating emotional valence into the attentional task-set. Together, our results portray hypnotic anger modulation as a two-tiered process: first, hypnotic suggestion alters the attentional task-set; second, provided processing and response preparation are not interrupted, a hypnotizability-dependent response based on said altered task-set is produced through late cognitive control strategies.

Nontarget emotional stimuli must be highly conspicuous to modulate the attentional blink

The attentional blink (AB) is often considered a top-down phenomenon because it is triggered by matching an initial target (T1) in a rapid serial visual presentation (RSVP) stream to a search template. However, the AB is modulated when targets are emotional, and is evoked when a task-irrelevant, emotional critical distractor (CDI) replaces T1. Neither manipulation fully captures the interplay between bottom-up and top-down attention in the AB: Valenced targets intrinsically conflate top-down and bottom-up attention. The CDI approach cannot manipulate second target (T2) valence, which is critical because valenced T2s can "break through" the AB (in the target-manipulation approach). The present research resolves this methodological challenge by indirectly measuring whether a purely bottom-up CDI can modulate report of a subsequent T2. This novel approach adds a valenced CDI to the "classic," two-target AB. Participants viewed RSVP streams containing a T1-CDI pair preceding a variable lag to T2. If the CDI's valence is sufficient to survive the AB, it should modulate T2 performance, indirectly signaling bottom-up capture by an emotional stimulus. Contrary to this prediction, CDI valence only affected the AB when CDIs were also extremely visually conspicuous. Thus, emotional valence alone is insufficient to modulate the AB.

Cerebellar lesions disrupt spatial and temporal visual attention

The current study represents the first comprehensive examination of spatial, temporal and sustained attention following cerebellar damage. Results indicated that, compared to controls, cerebellar damage resulted in a larger cueing effect at the longest SOA - possibly reflecting a slowed the onset of inhibition of return (IOR) during a reflexive covert attention task, and reduced the ability to detect successive targets during an attentional blink task. However, there was little evidence to support the notion that cerebellar damage disrupted voluntary covert attention or the sustained attention to response task (SART). Lesion overlay data and supplementary voxel-based lesion symptom mapping (VLSM) analyses indicated that impaired performance on the reflexive covert attention and attentional blink tasks were related to damage to Crus II of the left posterior cerebellum. In addition, subsequent analyses indicated our results are not due to either general motor impairments or to damage to the deep cerebellar nuclei. Collectively these data demonstrate, for the first time, that the same cerebellar regions may be involved in both spatial and temporal visual attention.

Representational dynamics preceding conscious access

Our senses are continuously bombarded with more information than our brain can process up to the level of awareness. The present study aimed to enhance understanding on how attentional selection shapes conscious access under conditions of rapidly changing input. Using an attention task, EEG, and multivariate decoding of individual target- and distractor-defining features, we specifically examined dynamic changes in the representation of targets and distractors as a function of conscious access and the task-relevance (target or distractor) of the preceding item in the RSVP stream. At the behavioral level, replicating previous work and suggestive of a flexible gating mechanism, we found a significant impairment in conscious access to targets (T2) that were preceded by a target (T1) followed by one or two distractors (i.e., the attentional blink), but striking facilitation of conscious access to targets shown directly after another target (i.e., lag-1 sparing and blink reversal). At the neural level, conscious access to T2 was associated with enhanced early- and late-stage T1 representations and enhanced late-stage D1 representations, and interestingly, could be predicted based on the pattern of EEG activation well before T1 was presented. Yet, across task conditions, we did not find convincing evidence for the notion that conscious access is affected by rapid top-down selection-related modulations of the strength of early sensory representations induced by the preceding visual event. These results cannot easily be explained by existing accounts of how attentional selection shapes conscious access under rapidly changing input conditions, and have important implications for theories of the attentional blink and consciousness more generally.

Neural Correlates of Attentional Bias to Food Stimuli in Obese Adolescents

Adolescent obesity is an increasingly prevalent problem in several societies. Researchers have begun to focus on neurocognitive processes that may help explain how unhealthy food habits form and are maintained. The present study compared attentional bias to food stimuli in a sample of obese (n = 22) and Normal-weight (n = 18) adolescents utilizing an Attention Blink (AB) paradigm while electroencephalography (EEG) was recorded. We found lower accuracy and Event-Related Potential (ERP) P3 amplitudes during the presentation of food stimuli in AB trials for obese adolescents. These findings suggest an impaired ability of their brains to flexibly relocate attentional resources in the face of food stimuli. The results were corroborated by lower P3s also being associated with higher body mass index (BMI) values and poorer self-reported self-efficacy in controlling food intake. The study is among the few examining neural correlates of attentional control in obese adolescents and suggests automatic attentional bias to food is an important aspect to consider in tackling the obesity crisis.

Subjective visibility report is facilitated by conscious predictions only

Predictions in the visual domain have been shown to modulate conscious access. Yet, little is known about how predictions may do so and to what extent they need to be consciously implemented to be effective. To address this, we administered an attentional blink (AB) task in which target 1 (T1) identity predicted target 2 (T2) identity, while participants rated their perceptual awareness of validly versus invalidly predicted T2s (Experiment 1 & 2) or reported T2 identity (Experiment 3). Critically, we tested the effects of conscious and non-conscious predictions, after seen and unseen T1s, on T2 visibility. We found that valid predictions increased subjective visibility reports and discrimination of T2s, but only when predictions were generated by a consciously accessed T1, irrespective of the timing at which the effects were measured (short vs. longs lags). These results further our understanding of the intricate relationship between predictive processing and consciousness.

An investigation of how relative precision of target encoding influences metacognitive performance

Detection failures in perceptual tasks can result from different causes: sometimes we may fail to see something because perceptual information is noisy or degraded, and sometimes we may fail to see something due to the limited capacity of attention. Previous work indicates that metacognitive capacities for detection failures may differ depending on the specific stimulus visibility manipulation employed. In this investigation, we measured metacognition while matching performance in two visibility manipulations: phase-scrambling and the attentional blink. As in previous work, metacognitive asymmetries emerged: despite matched type 1 performance, metacognitive ability (measured by area under the ROC curve) for reporting stimulus absence was higher in the attentional blink condition, which was mainly driven by metacognitive ability in correct rejection trials. We performed Signal Detection Theoretic (SDT) modeling of the results, showing that differences in metacognition under equal type I performance can be explained when the variance of the signal and noise distributions are unequal. Specifically, the present study suggests that phase scrambling signal trials have a wider distribution (more variability) than attentional blink signal trials, leading to a larger area under the ROC curve for attentional blink trials where subjects reported stimulus absence. These results provide a theoretical basis for the origin of metacognitive differences on trials where subjects report stimulus absence, and may also explain previous findings where the absence of evidence during detection tasks results in lower metacognitive performance when compared to categorization.

Time course of the unmasked attentional blink

The Attentional Blink (AB) usually refers to the impaired report of a second target (T2) if it appears within 200-500 ms after a first target within a rapid sequence of distractors. The present study focused on a less studied AB variant known as the unmasked AB, where T2 is the last item of the sequence and T2 report is unaffected. This aspect of the unmasked AB holds promise for an experimental paradigm in which measures of on-going event-related processing are unconfounded by differences in late-stage processing. To fully characterize the unmasked AB paradigm, we used a randomization statistics approach to comprehensively examine the electroencephalographic signature of the unmasked AB. We examined the unmasked AB with auditory and visual T2s-participants attended to either the auditory or visual information within a sequence of paired auditory-visual stimuli, and reported targets within the attended modality stream while ignoring the other. As predicted, T2 report was unaffected by the unmasked AB. The visual AB was associated with delayed but intact N2 and P3 components, and a suppressed N1. We suggest that this N1 is linked to auditory processing of the distractor stream, and reflects the cognitive system prioritizing the processing of visual targets over auditory distractors in response to AB-related processing load. The auditory AB only indicated a delayed but intact P3. Collectively, these findings support the view that the AB limits the entry of information into consciousness via a late-stage modal bottleneck, and suggest an ongoing compensatory response at early latencies.

Dual task interference on early perceptual processing

When two tasks, Task 1 and Task 2, are conducted in close temporal proximity and a separate speeded response is required for each target (T1 and T2), T2 report performance decreases as a function of its temporal proximity to T1. This so-called psychological refractory period (PRP) effect on T2 processing is largely assumed to reflect interference from T1 response selection on T2 response selection. However, interference on early perceptual processing of T2 has been observed in a modified paradigm, which required changes in visual-spatial attention, sensory modality, task modality, and response modality across targets. The goal of the present study was to investigate the possibility of early perceptual interference by systematically and iteratively removing each of these possible non perceptual confounds, in a series of four experiments. To assess T2 visual memory consolidation success, T2 was presented for a varying duration and immediately masked. T2 report accuracy, which was taken as a measure of perceptual-encoding or consolidation-success, decreased across all experimental control conditions as T1-T2 onset proximity increased. We argue that our results, in light of previous studies, show that central processing of a first target, responsible for the classical PRP effect, also interferes with early perceptual processing of a second target. We end with a discussion of broader implications for psychological refractory period and attentional blink effects.

Food is special by itself: Neither valence, arousal, food appeal, nor caloric content modulate the attentional bias induced by food images

When food cues appear in a visual context, such information is likely to influence eating behavior by enhancing attention for food cues. We investigated whether active but task-irrelevant information could modulate the attentional bias for food stimuli using a novel paradigm in which participants were purposely deceived by being enrolled in a memory experiment. A set of images were first held in working memory and then used as task-irrelevant distractors in a subsequent single target rapid serial visual presentation (RSVP) task, allowing us to investigate the attentional blink (AB) effect elicited by those images. In Experiment 1, the results revealed that food images elicited a larger AB effect than nonfood images. In three follow-up experiments, we investigated whether valence or arousal (Experiment 2), food preparation (Experiment 3), or food caloric content (Experiment 4) were factors related to the attentional bias for food. Overall, our results demonstrated that when held in working memory, food images can easily capture attention, even in circumstances in which the information retained in memory is irrelevant to solve the task, as indicated by the strong correlation found between items that were recognized in the RSVP task and the AB effect. Nonetheless, none of the food-related properties we examined were found to be associated with this attentional bias for food.

The attentional blink: A relational accountof attentional engagement

Visual attention allows selecting relevant information from cluttered visual scenes and is largely determined by our ability to tune or bias visual attention to goal-relevant objects. Originally, it was believed that this top-down bias operates on the specific feature values of objects (e.g., tuning attention to orange). However, subsequent studies showed that attention is tuned to in a context-dependent manner to the relative feature of a sought-after object (e.g., the reddest or yellowest item), which drives covert attention and eye movements in visual search. However, the evidence for the corresponding relational account is still limited to the orienting of spatial attention. The present study tested whether the relational account can be extended to explain attentional engagement and specifically, the attentional blink (AB) in a rapid serial visual presentation (RSVP) task. In two blocked conditions, observers had to identify an orange target letter that could be either redder or yellower than the other letters in the stream. In line with previous work, a target-matching (orange) distractor presented prior to the target produced a robust AB. Extending on prior work, we found an equally large AB in response to relatively matching distractors that matched only the relative color of the target (i.e., red or yellow; depending on whether the target was redder or yellower). Unrelated distractors mostly failed to produce a significant AB. These results closely match previous findings assessing spatial attention and show that the relational account can be extended to attentional engagement and selection of continuously attended objects in time.

The attentional blink unveils the interplay between conscious perception, spatial attention and working memory encoding

Our ability to perceive two events in close temporal succession is severely limited, a phenomenon known as the attentional blink. While the blink has served as a popular tool to prevent conscious perception, there is less research on its causes, and in particular on the role of conscious perception of the first event in triggering it. In three experiments, we disentangled the roles of spatial attention, conscious perception and working memory (WM) in causing the blink. We show that while allocating spatial attention to T1 is neither necessary nor sufficient for eliciting a blink, consciously perceiving it is necessary but not sufficient. When T1 was task irrelevant, consciously perceiving it triggered a blink only when it matched the attentional set for T2. We conclude that consciously perceiving a task-relevant event causes the blink, possibly because it triggers encoding of this event into WM. We discuss the implications of these findings for the relationship between spatial attention, conscious perception and WM, as well as for the distinction between access and phenomenal consciousness.

Conscious perception and the modulatory role of dopamine: no effect of the dopamine D2 agonist cabergoline on visual masking, the attentional blink, and probabilistic discrimination

RATIONALE

Conscious perception is thought to depend on global amplification of sensory input. In recent years, striatal dopamine has been proposed to be involved in gating information and conscious access, due to its modulatory influence on thalamocortical connectivity.

OBJECTIVES

Since much of the evidence that implicates striatal dopamine is correlational, we conducted a double-blind crossover pharmacological study in which we administered cabergoline-a dopamine D2 agonist-and placebo to 30 healthy participants. Under both conditions, we subjected participants to several well-established experimental conscious-perception paradigms, such as backward masking and the attentional blink task.

RESULTS

We found no evidence in support of an effect of cabergoline on conscious perception: key behavioral and event-related potential (ERP) findings associated with each of these tasks were unaffected by cabergoline.

CONCLUSIONS

Our results cast doubt on a causal role for dopamine in visual perception. It remains an open possibility that dopamine has causal effects in other tasks, perhaps where perceptual uncertainty is more prominent.

Fearful expressions of rapidly presented hybrid-faces modulate the lag 1 sparing in the attentional blink

There is evidence that emotional stimuli impair attention for subsequent stimuli when presented in rapid visual succession. We investigated whether non-visible emotions of hybrid faces showing either happy or afraid expressions only in their Low Spatial Frequencies (LSF) and neutral expressions in their High Spatial Frequencies (HSF) modulate temporal selective attention. In a Rapid Serial Visual Presentation (RSVP) paradigm, two target-faces (T1 and T2) were presented briefly at different temporal distances (lags) in a stream of inverted distractor-faces: T1s were either neutral, happy-hybrid or afraid-hybrid faces; T2s were always neutral faces. When participants reported T1 and T2 gender, performance was impaired across all early lags, especially after afraid-hybrid faces. When participants reported T1 orientation and T2 gender, results showed that the LSF emotion of T1s affected temporal selective attention engendering a longer AB (over lag 2 and lag 3) than neutral T1s. Interestingly, only afraid-hybrid T1s improved processing of T2 at lag 1 (i.e., sparing). Our findings show that some core emotional content is implicitly processed from the LSF of hybrid T1s since the effects on temporal selective attention are emotion specific.

A Skill-Based Approach to Modeling the Attentional Blink

People can often learn new tasks quickly. This is hard to explain with cognitive models because they either need extensive task‐specific knowledge or a long training session. In this article, we try to solve this by proposing that task knowledge can be decomposed into skills. A skill is a task‐independent set of knowledge that can be reused for different tasks. As a demonstration, we created an attentional blink model from the general skills that we extracted from models of visual attention and working memory. The results suggest that this is a feasible modeling method, which could lead to more generalizable models.

People can learn to perform new tasks very quickly by making use of lower‐level skills they have developed when learning previous tasks. Hoekstra, Martens, and Taatgen model this process, showing how a system trained on simple tasks (visual search and two working memory tasks) can then quickly learn to perform the attentional blink task, and it ends up making the same sorts of errors as people do.

The impact of sleep loss on sustained and transient attention: an EEG study

Sleep is one of our most important physiological functions that maintains physical and mental health. Two studies examined whether discrete areas of attention are equally affected by sleep loss. This was achieved using a repeated-measures within-subjects design, with two contrasting conditions: normal sleep and partial sleep restriction of 5-h. Study 1 compared performance on a sustained attention task (Psychomotor Vigilance task; PVT) with performance on a transient attention task (Attentional Blink; AB). PVT performance, but not performance on the AB task, was impaired after sleep restriction. Study 2 sought to determine the neural underpinnings of the phenomenon, using electroencephalogram (EEG) frequency analysis, which measured activity during the brief eyes-closed resting state before the tasks. AB performance was unaffected by sleep restriction, despite clearly observable changes in brain activity. EEG results showed a significant reduction in resting state alpha oscillations that was most prominent centrally in the right hemisphere. Changes in individual alpha and delta power were also found to be related to changes in subjective sleepiness and PVT performance. Results likely reflect different levels of impairment in specific forms of attention following sleep loss.

Temporal predictability does not impact attentional blink performance: effects of fixed vs. random inter-trial intervals

Background

Does the inclusion of a randomized inter-trial interval (ITI) impact performance on an Attentional Blink (AB) task? The AB phenomenon is often used as a test of transient attention (Dux & Marois, 2009); however, it is unclear whether incorporating aspects of sustained attention, by implementing a randomized ITI, would impact task performance. The current research sought to investigate this, by contrasting a standard version of the AB task with a random ITI version to determine whether performance changed, reflecting a change in difficulty, engagement, or motivation.

Method

Thirty university students (21 female; age range 18–57, M_age= 21.5, SD = 7.4) completed both versions of the task, in counterbalanced order.

Results

No significant difference in performance was found between the standard AB task and the AB task with the random ITI. Bayesian analyses suggested moderate evidence for the null.

Conclusion

Temporal unpredictability did not appear to impact task performance. This suggests that the standard AB task has cognitive properties with regards to task difficulty, engagement, and motivation, that are inherently similar to tasks that employ a randomized ITI to measure sustained attention (e.g., the Psychomotor Vigilance Task; PVT; Dinges & Powell, 1985). This finding provides important support for future research which may seek to obtain a more detailed understanding of attention through the comparison of performance on transient and sustained attention tasks.

Impaired emotional biases in visual attention after bilateral amygdala lesion

It is debated whether the amygdala is critical for the emotional modulation of attention. While some studies show reduced attentional benefits for emotional stimuli in amygdala-damaged patients, others report preserved emotional effects. Various factors may account for these discrepant findings, including the temporal onset of the lesion, the completeness and severity of tissue damage, or the extent of neural plasticity and compensatory mechanisms, among others. Here, we investigated a rare patient with focal acute destruction of bilateral amygdala and adjacent hippocampal structures after late-onset herpetic encephalitis in adulthood. We compared her performance in two classic visual attention paradigms with that of healthy controls. First, we tested for any emotional advantage during an attentional blink task. Whereas controls showed better report of fearful and happy than neutral faces on trials with short lags between targets, the patient showed no emotional advantage, but also globally reduced report rates for all faces. Second, to ensure that memory disturbance due to hippocampal damage would not interfere with report performance, we also used a visual search task with either emotionally or visually salient face targets. Although the patient still exhibited efficient guided search for visually salient, non-emotional faces, her search slopes for emotional versus neutral faces showed no comparable benefit. In both tasks, however, changes in the patient predominated for happy more than fear stimuli, despite her normal explicit recognition of happy expressions. Our results provide new support for a causal role of the amygdala in emotional facilitation of visual attention, especially under conditions of increasing task-demands, and not limited to negative information. In addition, our data suggest that such deficits may not be amenable to plasticity and compensation, perhaps due to sudden and late-onset damage occurring in adulthood.

Spotting rare items makes the brain "blink" harder: Evidence from pupillometry

In many visual search tasks (e.g., cancer screening, airport baggage inspections), the most serious search targets occur infrequently. As an ironic side effect, when observers finally encounter important objects (e.g., a weapon in baggage), they often fail to notice them, a phenomenon known as the low-prevalence effect (LPE). Although many studies have investigated LPE search errors, we investigated the attentional consequences of successful rare target detection. Using an attentional blink paradigm, we manipulated how often observers encountered the first serial target (T1), then measured its effects on their ability to detect a following target (T2). Across two experiments, we show that the LPE is more than just an inflated miss rate: When observers successfully detected rare targets, they were less likely to spot subsequent targets. Using pupillometry to index locus-coeruleus (LC) mediated attentional engagement, Experiment 2 confirmed that an LC refractory period mediates the attentional blink (`Nieuwenhuis, Gilzenrat, Holmes, & Cohen, 2005, Journal of Experimental Psychology: General, 134[3], 291-307), and that these effects emerge relatively quickly following T1 onset. Moreover, in both behavioral and pupil analyses, we found that detecting low-prevalence targets exacerbates the LC refractory period. Consequences for theories of the LPE are discussed.