Showing papers on "Attentional blink published in 2011"

Pulsed out of awareness: EEG alpha oscillations represent a pulsed-inhibition of ongoing cortical processing

Abstract: Alpha oscillations are ubiquitous in the brain, but their role in cortical processing remains a matter of debate. Recently, evidence has begun to accumulate in support of a role for alpha oscillations in attention selection and control. Here we first review evidence that 8-12 Hz oscillations in the brain have a general inhibitory role in cognitive processing, with an emphasis on their role in visual processing. Then, we summarize the evidence in support of our recent proposal that alpha represents a pulsed-inhibition of ongoing neural activity. The phase of the ongoing electroencephalography can influence evoked activity and subsequent processing, and we propose that alpha exerts its inhibitory role through alternating microstates of inhibition and excitation. Finally, we discuss evidence that this pulsed-inhibition can be entrained to rhythmic stimuli in the environment, such that preferential processing occurs for stimuli at predictable moments. The entrainment of preferential phase may provide a mechanism for temporal attention in the brain. This pulsed inhibitory account of alpha has important implications for many common cognitive phenomena, such as the attentional blink, and seems to indicate that our visual experience may at least some times be coming through in waves.

Learned value magnifies salience-based attentional capture

Abstract: Visual attention is captured by physically salient stimuli (termed salience-based attentional capture), and by otherwise task-irrelevant stimuli that contain goal-related features (termed contingent attentional capture). Recently, we reported that physically nonsalient stimuli associated with value through reward learning also capture attention involuntarily (Anderson, Laurent, & Yantis, PNAS, 2011). Although it is known that physical salience and goal-relatedness both influence attentional priority, it is unknown whether or how attentional capture by a salient stimulus is modulated by its associated value. Here we show that a physically salient, task-irrelevant distractor previously associated with a large reward slows visual search more than an equally salient distractor previously associated with a smaller reward. This magnification of salience-based attentional capture by learned value extinguishes over several hundred trials. These findings reveal a broad influence of learned value on involuntary attentional capture.

A Unified attentional bottleneck in the human brain

Abstract: Human information processing is characterized by bottlenecks that constrain throughput. These bottlenecks limit both what we can perceive and what we can act on in multitask settings. Although perceptual and response limitations are often attributed to independent information processing bottlenecks, it has recently been suggested that a common attentional limitation may be responsible for both. To date, however, evidence supporting the existence of such a “unified” bottleneck has been mixed. Here, we tested the unified bottleneck hypothesis using time-resolved fMRI. Experiment 1 isolated brain regions involved in the response selection bottleneck that limits speeded dual-task performance. These same brain regions were not only engaged by a perceptual encoding task in Experiment 2, their activity also tracked delays to a speeded decision-making task caused by concurrent perceptual encoding (Experiment 3). We conclude that a unified attentional bottleneck, including the inferior frontal junction, superior medial frontal cortex, and bilateral insula, temporally limits operations as diverse as perceptual encoding and decision-making.

Attentional episodes in visual perception

Abstract: Is one's temporal perception of the world truly as seamless as it appears? This article presents a computationally motivated theory suggesting that visual attention samples information from temporal episodes (episodic simultaneous type/serial token model; Wyble, Bowman, & Nieuwenstein, 2009). Breaks between these episodes are punctuated by periods of suppressed attention, better known as the attentional blink (Raymond, Shapiro, & Arnell, 1992). We test predictions from this model and demonstrate that participants were able to report more letters from a sequence of 4 targets presented in a dense temporal cluster than from a sequence of 4 targets interleaved with nontargets. However, this superior report accuracy comes at a cost in impaired temporal order perception. Further experiments explore the dynamics of multiple episodes and the boundary conditions that trigger episodic breaks. Finally, we contrast the importance of attentional control, limited resources, and memory capacity constructs in the model.

Detection of emotional faces is modulated by the direction of eye gaze.

Abstract: Emotionally expressive faces have shown enhanced detectability over neutral faces, but little is known about the effect of eye gaze on detecting the presence of emotional faces. Emotional expressions and gaze direction are both cues to the intentions of another person, and gaze direction has been shown to affect recognition accuracy and perceived intensity of emotional faces. The current study showed that fearful faces were detected more frequently with an averted gaze than with a direct gaze in an attentional blink task, whereas angry and happy faces were detected more frequently with a direct gaze than with an averted gaze. The results are in line with the shared signal hypothesis and appraisal theory and suggest that selection for awareness was based on a rapid evaluation of the intentions of another person as conveyed by their facial expression and gaze direction.

The initial stage of visual selection is controlled by top-down task set: new ERP evidence.

Abstract: Salient visual singleton stimuli produce spatial cueing effects indicative of attentional capture only when they match current task sets, suggesting that capture is subject to top-down control. However, such task-set contingent capture effects could be associated with the top-down controlled disengagement of attention from non-matching stimuli that follows their initial bottom-up salience-driven selection. Using the N2pc component as an event-related potential marker of attentional capture, we demonstrate that top-down task set already controls the initial rapid selection of salient visual singleton stimuli prior to any subsequent attentional disengagement. These findings provide new evidence for the primacy of top-down control over bottom-up salience in attentional capture.

Visual Temporal Processing in Dyslexia and the Magnocellular Deficit Theory: The Need for Speed?.

Abstract: A controversial question in reading research is whether dyslexia is associated with impairments in the magnocellular system and, if so, how these low-level visual impairments might affect reading acquisition. This study used a novel chromatic flicker perception task to specifically explore temporal aspects of magnocellular functioning in 40 children with dyslexia and 42 age-matched controls (aged 7-11). The relationship between magnocellular temporal resolution and higher-level aspects of visual temporal processing including inspection time, single and dual-target (attentional blink) RSVP performance, go/no-go reaction time, and rapid naming was also assessed. The Dyslexia group exhibited significant deficits in magnocellular temporal resolution compared with controls, but the two groups did not differ in parvocellular temporal resolution. Despite the significant group differences, associations between magnocellular temporal resolution and reading ability were relatively weak, and links between low-level temporal resolution and reading ability did not appear specific to the magnocellular system. Factor analyses revealed that a collective Perceptual Speed factor, involving both low-level and higher-level visual temporal processing measures, accounted for unique variance in reading ability independently of phonological processing, rapid naming, and general ability. (PsycINFO Database Record (c) 2011 APA, all rights reserved). Language: en

Temporal processing of emotional stimuli: The capture and release of attention by angry faces.

Abstract: Neuroimaging data suggest that emotional information, especially threatening faces, automatically captures attention and receives rapid processing. While this is consistent with the majority of behavioral data, behavioral studies of the attentional blink (AB) additionally reveal that aversive emotional first target (T1) stimuli are associated with prolonged attentional engagement or "dwell" time. One explanation for this difference is that few AB studies have utilized manipulations of facial emotion as the T1. To address this, schematic faces varying in expression (neutral, angry, happy) served as the T1 in the current research. Results revealed that the blink associated with an angry T1 face was, primarily, of greater magnitude than that associated with either a neutral or happy T1 face, and also that initial recovery from this processing bias was faster following angry, compared with happy, T1 faces. The current data therefore provide important information regarding the time-course of attentional capture by angry faces: Angry faces are associated with both the rapid capture and rapid release of attention.

The costs of switching attentional sets

Abstract: People prioritize those aspects of the visual environment that match their attentional set. In the present study, we investigated whether switching from one attentional set to another is associated with a cost. We asked observers to sequentially saccade toward two color-defined targets, one on the left side of the display, the other on the right, each among a set of heterogeneously colored distractors. The targets were of the same color (no attentional set switch required) or of different colors (switch of attentional sets necessary), with each color consistently tied to a side, to allow observers to maximally prepare for the switch. We found that saccades were less accurate and slower in the switch condition than in the no-switch condition. Furthermore, whenever one of the distractors had the color associated with the other attentional set, a substantial proportion of saccades did not end on the target, but on this distractor. A time course analysis revealed that this distractor preference turned into a target preference after about 250–300 ms, suggesting that this is the time required to switch attentional sets.

Consciousness of targets during the attentional blink: a gradual or all-or-none dimension?

Abstract: Models of consciousness differ in whether they predict a gradual change or a discontinuous transition between nonconscious and conscious perception. Sergent and Dehaene (Psychological Science, 15, 720–728, 2004) asked subjects to rate on a continuous scale the subjective visibility of target words presented during an attentional blink. They found that these words were either detected as well as targets outside the attentional-blink period or not detected at all, and interpreted these results as support for a discontinuous transition between nonconscious and conscious processing. We present results from 4 attentional-blink experiments showing that this all-or-none rating pattern disappears with the use of an alternative measure of consciousness (post-decision wagering) and a more difficult identification task. Instead, under these circumstances, subjects used the consciousness rating scales in a continuous fashion. These results are more consistent with models that assume a gradual change between nonconscious and conscious perception during the attentional blink.

The attentional blink demonstrates automatic deviance processing in vision

Abstract: Rare deviations in serial visual stimulation are accompanied by an occipital N2 in the event-related potential [the visual mismatch negativity (vMMN)]. Recent research suggests that the vMMN reflects automatic processing of information on the sensory level as a basis for change detection. To directly test the hypothesis that the vMMN is independent from attention, a rapid-serial-visual-presentation paradigm was applied: Either 300 ms or 700 ms after the presentation of a target (T1) a rare position change was embedded in the stimulation which elicited a vMMN. In another condition participants had to detect a second target (T2) after T1: Importantly, within 300 ms after T1, T2 detection was nearly chance level ('attentional blink'). This result demonstrates that the vMMN is elicited without attentional allocation.

Dopamine and the management of attentional resources: Genetic markers of striatal d2 dopamine predict individual differences in the attentional blink

Abstract: The attentional blink (AB)-a deficit in reporting the second of two target stimuli presented in close succession in a rapid sequence of distracters-has been related to processing limitations in working memory. Given that dopamine (DA) plays a crucial role working memory, the present study tested whether individual differences in the size of the AB can be predicted by differences in genetic predisposition related to the efficiency of dopaminergic pathways. Polymorphisms related to mesocortical and nigrostriatal dopaminergic pathways were considered, as well as polymorphisms related to norepinephrine (NE), a transmitter system that has also been suspected to play a role in the AB. In a sample of 157 healthy adults, we studied the dependency of the individual magnitude of the AB and the C957T polymorphism at the DRD2 gene (associated with striatal DA/D2 receptors), the DARPP32 polymorphism (associated with striatal DA/D1), the COMT Val158Met polymorphism (associated with frontal DA), DBH444 g/a and DBH5'-ins/del polymorphisms (polymorphisms strongly correlated with DA beta hydroxylase, the enzyme catalyzing the DA-NE conversion) and NET T-182C (a polymorphism related to the NE transporter). DRD2 C957T T/T homozygotes showed a significantly smaller AB, whereas polymorphisms associated with frontal DA and NE were unrelated to performance. This outcome pattern suggests a crucial role of the nigrostriatal dopaminergic pathway and of nigrostriatal D2 receptors, in particular, in the management of attentional resources.

Prior entry explains order reversals in the attentional blink

Abstract: When two targets are presented in rapid succession, the first target (T1) is usually identified, but the second target (T2) is often missed. A remarkable exception to this “attentional blink” occurs when T2 immediately follows the first T1, at lag 1. It is then often spared but reported in the wrong order—that is, before T1. These order reversals have led to the hypothesis that “lag 1 sparing” occurs because the two targets merge into a single episodic representation. Here, we report evidence consistent with an alternative theory: T2 receives more attention than T1, leading to prior entry into working memory. Two experiments showed that the more T2 performance exceeded that for T1, the more order reversals were made. Furthermore, precuing T1 led to a shift in performance benefits from T2 to T1 and to an equivalent reduction in order reversals. We conclude that it is not necessary to assume episodic integration to explain lag 1 sparing or the accompanying order reversals.

Short-Term Training in Loving-Kindness Meditation Produces a State, But Not a Trait, Alteration of Attention

Abstract: While mindfulness meditation has been associated with enhanced attentional abilities, the consequences of loving-kindness meditation for attention have not previously been investigated. We examined the trait and state effects of 8 weeks of training in loving-kindness meditation (LKM) on the attentional blink. The attentional blink is a period of time in which a target stimulus is less likely to be detected if it follows too quickly (approximately 500 ms) after a previously detected target. For the two experiments reported here, a group of participants trained in LKM by meditating for approximately 15 min per day, four days per week, for 8 weeks. Experiment 1 utilized a pre-post design, with a non-meditating control group, to examine whether this training reduced the attentional blink. No differences were found. However, in an exploratory analysis, meditators did exhibit increases in two facets of mindfulness measured by the Five Facet Mindfulness Questionnaire: observation and descriptiveness. In experiment 2, we tested for a state effect of LKM by having trained meditators practice LKM immediately prior to the attentional blink task. Here, meditators had a significantly reduced blink size compared to control participants. To establish that this reduction was caused by the combination of LKM training with pre-task meditation, we analyzed the data in experiment 2 with respect to one of our previous works, which reported that the practice of LKM immediately prior to the attentional blink task in those without meditation training did not reduce the blink magnitude. This analysis also revealed a significant difference. Therefore, training in LKM, coupled with its practice immediately prior to an attention task, caused a state reduction in the attentional blink. These results are the first to demonstrate that LKM, an emotion-focused practice, influences cognitive processing.

Different Attentional Blink Tasks Reflect Distinct Information Processing Limitations: An Individual Differences Approach.

Abstract: Due to our limited attentional resources, in a given instance, we are only aware of a fraction of the information available in our complex visual environment. In the laboratory, such capacity limitations are reflected in the Attentional Blink (AB) task: Participant‟s inability to report the second target (T2) in a rapid serial visual presentation (RSVP) stream of distractors if it occurs within 200-500ms of the first target (T1). Over the last two decades this phenomenon has undergone intense investigation. A variety of different paradigms have been employed to examine the AB, all yielding similar T2|T1 accuracy time courses. Consequently, it has been assumed that these different tasks tap the same cognitive mechanisms, however to date this has not been tested. This thesis examined whether three prominent AB tasks: categorical (targets defined by alpha numeric category e.g., letters amongst digits), featural (targets defined by colour) and probe (T1 defined by colour, T2 by identity) paradigms reflect the same cognitive limitation. Using an individual differences approach, where 40 participants undertook 2 runs of each AB task it was observed that while there was high test-retest reliability for each paradigm, only AB magnitude for the featural and categorical tasks were correlated. Thus, it appears that categorical and featural AB tasks reflect distinct limitations relative to the probe paradigm. The results have important implications for theories of temporal attention as it appears there may be distinct information processing bottlenecks at the level of selection.

Human Attention in Digital Environments: Human attention and its implications for human–computer interaction

Abstract: Remembering planned activities, resuming tasks previously interrupted, recalling the names of colleagues, sustaining focused performance under the pressure of interruptions, ensuring that we don't miss important information…these are only a few examples of critical activities whose performance is guided by attentional processes. This chapter proposes that knowledge about attentional processes can help us design systems that support users in situations such as those described above. The first part of the chapter gives an overview of some of the essential theoretical findings about human attention. The second part analyses attentional breakdowns and how those theoretical findings may be applied in order to design systems that either help avoid attentional breakdowns or assist in recovering from them . Introduction Current information and communication technologies concentrate on providing services to users performing focused activities. However, focused activity is no longer the norm. Users are often interrupted, they switch between the contexts of different devices and tasks, maintain awareness about the activity of distant collaborators and manage very large quantities of information. All this results in high cognitive load that may hinder users' overall achievements. In order to address interaction in a more realistic manner, we have been working on the development of systems that are capable of supporting the processes that govern human cognitive resources allocation: attentional processes.

A selective impairment in attentional disengagement from erotica in obsessive–compulsive disorder

Abstract: Although an attentional bias for threat has been implicated in obsessive–compulsive disorder (OCD), evidence supporting such a bias has been inconsistent. Furthermore, few studies have made distinctions between attentional capture vs. attentional disengagement and the extent to which different emotional content modulates attention in OCD also remains unclear. To address these issues, we examined patients with OCD ( n = 30) and controls ( n = 30) during an emotional attentional blink paradigm in which participants searched for a target embedded within a series of rapidly presented images. Critically, an erotic, fear, disgust, or neutral distracter image appeared 200 ms or 800 ms before the target. Impaired target detection was observed among OCD patients relative to controls following erotic distracters, but only when presented 800 ms, and not 200 ms, prior to the target, indicating difficulty with attentional disengagement. Difficulty disengaging from erotic images was significantly correlated with OCD symptoms in the full sample but not with symptoms of trait anxiety. These data delineate a specific information processing abnormality in OCD.

Distractor devaluation effect in the attentional blink: direct evidence for distractor inhibition.

Abstract: When two targets (T1 and T2) are embedded in rapid serial visual presentation (RSVP), T2 is often missed (attentional blink, AB) if T2 follows T1 by less than 500 ms. Some have proposed that inhibition of a distractor following T1 contributes to the AB, but no direct evidence supports this proposal. This study examined distractor inhibition by assessing a distractor devaluation effect where inhibited items were evaluated less positively than controls. Experiments 1 and 2 showed that a distractor presented just after T1 was evaluated less favorably when T2 was misidentified, independently of stimulus characteristics. Experiment 3 produced distractor devaluation in T2 incorrect trials when the evaluated distractor was the second item after T1. In contrast, a distractor presented before T1 was not devaluated (Experiment 4). Experiment 5 demonstrated that participants could not recognize presented distractors after an RSVP task, rejecting the possibility that memorized distractors were devalued. Results show a relationship between the devaluation of distractors following T1 and the AB, providing the first direct evidence of the distractor inhibition during the AB.

Temporal attention facilitates short-term consolidation during a rapid serial auditory presentation task

Abstract: Attentional blink (AB) refers to a phenomenon where the correct identification of a first target (i.e., target) impairs the processing of a second target (i.e., probe) nearby in time. In the present study, we investigate the influence of temporal attention on auditory AB by means of scalp-recorded event-related potentials. Participants were instructed to focus their attention on a particular time interval following the target (i.e., short, middle, or long temporal position) in order to detect the occurrence of the probe in a rapid series of distractor sounds. We found a large probe processing deficit when the probe occurred immediately after the target. This AB decreased as the time interval between the target and the probe increased and coincided with the generation of a positive wave at parietal sites (i.e., P3b). The P3b elicited by the probe peaked earlier when the probe occurred at the designated time than when it occurred at another position in time. The results indicate that temporal attention can be deployed to a particular time, which facilitates short-term consolidation of the probe.