The influence of temporal selection on spatial selection and distractor interference: an attentional blink study.

Both spatial and temporal selection require focused attention. The authors examine how temporal attention affects spatial selection. In a dual-task rapid serial visual presentation paradigm, temporal selection of a target (T1) impairs processing of a second target (T2) that follows T1 within 500 ms. This process is the attentional blink (AB). To test the effects of withdrawing temporal attention, the authors measured concurrent distractor interference on T2 when the distractors were presented during and outside of the AB. Perceptual interference was manipulated by the similarity in color between T2 and concurrent distractors, and response interference was manipulated by the flanker congruency task. Results showed that perceptual interference was larger during the AB. Response interference also increased during the AB, but only when perceptual interference was high. The authors conclude that temporal selection and spatial selection rely on a common attentional process.     

Impaired temporal discrimination within the attentional blink

Yeshurun and Levy (2003) reported that temporal discrimination performance of a visual stimulus benefits when spatial attention is oriented away from its location. In the present study, we investigated whether this negative influence of attention on temporal discrimination performance is restricted to transient spatial attention or might generalize to other paradigms of attention. We employed the attentional blink (AB) paradigm and required either a spatial (Experiment 1) or a temporal discrimination task (Experiment 2). The results of both experiments revealed a performance decrement if attention was temporally unavailable during the AB and a recovery with increasing attentional availability. Thus, contrary to the results of Yeshurun and Levy, the absence of attention decreased temporal discrimination performance in this paradigm. We hypothesize that attention which operates at different processing levels might exert differential effects on temporal stimulus processing.     

The role of the magnocellular visual pathway in the attentional blink

Visual attention has temporal limitations. In the attentional blink (AB) a stream of stimuli such as letters or digits are presented to a participant on a computer monitor at a rapid rate. Embedded in the stream are two targets that the participant must try to identify. Identification of the second target is severely impaired if it is presented within approximately 500ms of the first target. This is the 'blink' in visual attention. In this study we examined the role of the magnocellular visual pathway in the AB. This fast conducting pathway has high temporal resolution and contrast sensitivity. It is also insensitive to the direction of chromatic contrast, and this attribute was exploited in order to isolate its contributions to temporal attention. Colour defined, luminance noise masked AB streams were compared to AB streams of varying achromatic contrast. The four observers, (2F and 2M) aged between 21 and 35years, had normal visual acuity and colour vision. The colour stimuli produced a similar blink to the moderate contrast achromatic stimuli. This indicates that the magnocellular pathway does not have a privileged role in the attentional blink. We provide an explanation of previous apparently contradictory findings in terms of the role of different types of visual masking in the attentional blink.     

The attentional blink: A review of data and theory

Under conditions of rapid serial visual presentation, subjects display a reduced ability to report the second of two targets(Target2; T2) in a stream of distractors if it appearswithin200-500 msec of Target 1 (Tl). This effect. known as the attentional blink(AB),has been central in characterizing the limits of humans’ ability to consciously perceive stimuli distributed across time. Here, we review theoretical accounts of the AB and examine how they explain key findings in the literature. We conclude that the AB arises from attentional demands of Tl for selection, working memory encoding, episodic registration,and response selection, which prevents this high-level central resource from being applied to T2 at shortT1-T2 lags. Tl processing also transiently impairs the redeployment of these attentional resources to subsequent targets and the inhibition of distractors that appear in close temporal proximity to T2. Although these findings are consistent with a multifactorial account of the AB,they can also be largely explained by assuming that the activation of these multiple processes depends on a common capacity-limited attentional process for selecting behaviorally relevant events presented among temporally distributed distractors. Thus, at its core, the attentional blink may ultimately reveal the temporal limits of the deployment of selective attention.     

Distraction and the auditory attentional blink

When two target stimuli (T1 and T2) are presented in close succession within a stimulus sequence, detection or discrimination performance for T2 is often impaired; this phenomenon is called the attentional blink (AB). Growing evidence suggests that the AB is present not only for visual, but also for auditory stimuli. Because sounds have a strong potential to attract attention when they are presented after longer silent intervals or in a sequence from which they stand out because of their rare or novel physical features, it seems possible that the involuntary and excessive allocation of attention to T1 (distraction) may contribute to the AB. By varying the saliency of T1, we showed that distraction does contribute to the auditory AB effect, but the contribution is short-lived: Only stimuli immediately following T1 are affected.     

Attentional requirements is visual detection and identification: evidence from the attentional blink

Perception of the 2nd of 2 targets (T1 and T2) is impaired if the lag between them is short (0-500 ms). The authors used this attentional blink (AB) to index attentional requirements in detection and identification tasks, with or without backward masking of T2, in 2 stimulus domains (line orientation, coherent motion). With masking, the AB occurred because T2 was masked during the attentional dwell time created by T1 processing (Experiments 1, 2, and 3). Without masking, an AB occurred only in identification because during the attentional dwell time, T2 decayed to a level that could support simple detection but not complex identification. However, an AB occurred also in detection if T2 was sufficiently degraded (Experiment 4). The authors drew 2 major conclusions: (a) Attention is required in both identification and detection, and (b) 2 factors contribute to the AB, masking of T2 while attention is focused on T1 and decay of the T2 trace while unattended.     

Perceptual load modulates the processing of distractors presented at task-irrelevant locations during the attentional blink

The distribution of attention in both space and time is critical for processing our dynamic environment. Studies of spatial attention suggest that the distribution of attention is decreased when the perceptual load of a task increases, resulting in decreased processing of task-irrelevant distractors. Studies of the attentional blink (AB) suggest that the temporal distribution of attention also influences distractor processing, such that distractor processing increases during the AB relative to outside the AB (Jiang & Chun, 2001). Two experiments are reported in which the extent to which the difficulty of the first target task (T1) modulates the processing of task-irrelevant distractors during the AB was tested. To investigate this issue, both the first and second target tasks (T1 and T2) required identifying a central stimulus that was flanked by low-load or high-load distractors. Consistent with previous studies of the AB, there was evidence of more distractor processing during the AB than outside the AB. Critically, however, the interference caused by distractors presented simultaneously with T2 during the AB was reduced when T1 perceptual load was high relative to when it was low. These results suggest that increasing T1 perceptual load decreases distractor processing during the AB and that perceptual processes influence both the temporal and spatial distribution of attention.     

Attentional disengagement in adults with Williams syndrome

Williams syndrome (WS) is a neurodevelopmental disorder characterized by a distinctive behavioral and cognitive profile, including widespread problems with attention. However, the specific nature of their attentional difficulties, such as inappropriate attentional allocation and/or poor attentional disengagement abilities, has yet to be elucidated. Furthermore, it is unknown if there is an underlying difficulty with the temporal dynamics of attention in WS or if their attentional difficulties are task-dependent, because previous studies have examined attention in established areas of deficit and atypicality (specifically, visuospatial and face processing). In this study, we examined attentional processing in 14 adults with WS (20–59 years) and 17 typically developing controls (19–39 years) using an attentional blink (AB) paradigm. The AB is the decreased ability to detect a second target when it is presented in close proximity to an initial target. Overall, adults with WS had an AB that was prolonged in duration, but no different in magnitude, compared with typically developing control participants. AB performance was not explained by IQ, working memory, or processing speed in either group. Thus, results suggest that the attention problems in WS are primarily due to general attentional disengagement difficulties rather than inappropriate attentional allocation.     

Amplification of attentional blink by distress‐related facial expressions: Relationships with alexithymia and affectivity

The present studies aimed to analyse the modulatory effect of distressing facial expressions on attention processing. The attentional blink (AB) paradigm is one of the most widely used paradigms for studying temporal attention, and is increasingly applied to study the temporal dynamics of emotion processing. The aims of this study were to investigate how identifying fear and pain facial expressions (Study 1) and fear and anger facial expressions (Study 2) would influence the detection of subsequent stimuli presented within short time intervals, and to assess the moderating influence of alexithymia and affectivity on this effect. It has been suggested that high alexithymia scorers need more attentional resources to process distressing facial expressions and that negative affectivity increases the AB. We showed that fear, anger and pain produced an AB and that alexithymia moderated it such that difficulty in describing feelings (Study 1) and externally oriented thinking (Study 2) were associated with higher interference after the processing of fear and anger at short time presentations. These studies provide evidence that distressing facial expressions modulate the attentional processing at short time intervals and that alexithymia influences the early attentional processing of fear and anger expressions. Controlling for state affect did not change these conclusions.     

Delayed attentional engagement in the attentional blink

Observers often miss the 2nd of 2 visual targets (first target [T1] and second target [T2]) when these targets are presented closely in time; the attentional blink (AB). The authors hypothesized that the AB occurs because the attentional response to T2 is delayed by T1 processing, causing T2 to lose a competition for attention to the item that follows it. The authors investigated this hypothesis by determining whether the AB is attenuated when T2 is precued. The results from 4 experiments showed that the duration and magnitude of the AB were substantially reduced when T2 was precued. The observed improvement in T2 report did not occur at the expense of T1 report, suggesting that processing of T1 was already completed or was at least protected when the cue was presented. The authors conclude that, during the AB, there is a delay between detection and the selection of target candidates for consolidation in short-term memory.     

Attentional and perceptual factors affecting the attentional blink for faces and objects

When 2 different visual targets presented among different distracters in a rapid serial visual presentation (RSVP) are separated by 400 ms or less, detection and identification of the 2nd targets are reduced relative to longer time intervals. This phenomenon, termed the attentional blink (AB), is attributed to the temporary engagement of a limited-capacity attentional system by the 1st target, which reduces resources available for processing the 2nd target. Although AB has been reliably obtained with many stimulus types, it has not been found for faces (E. Awh et al., 2004). In the present study, the authors investigate the underpinnings of this immunity. Unveiling circumstances in which AB occurs within and across faces and other categories, the authors demonstrate that a multichannel model cannot account for the absence of AB effects on faces. The authors suggest instead that perceptual salience of the face within the distracters' series as well as the available resources determine whether or not faces are blinked in RSVP.     

How the brain blinks: towards a neurocognitive model of the attentional blink

When people monitor a visual stream of rapidly presented stimuli for two targets (T1 and T2), they often miss T2 if it falls into a time window of about half a second after T1 onset-the attentional blink (AB). We provide an overview of recent neuroscientific studies devoted to analyze the neural processes underlying the AB and their temporal dynamics. The available evidence points to an attentional network involving temporal, right-parietal and frontal cortex, and suggests that the components of this neural network interact by means of synchronization and stimulus-induced desynchronization in the beta frequency range. We set up a neurocognitive scenario describing how the AB might emerge and why it depends on the presence of masks and the other event(s) the targets are embedded in. The scenario supports the idea that the AB arises from "biased competition", with the top-down bias being generated by parietal-frontal interactions and the competition taking place between stimulus codes in temporal cortex.     

Evidence for distinct attentional bottlenecks in attention switching and attentional blink tasks

E. Weichselgartner and G. A. Sperling (1987), using rapid serial visual presentation (RSVP), estimated that attention could be moved to a new spatial location within 300-400 ms. H. J. Müller and P. M. Rabbit (1989) used a spatial cuing task and found a similar time course for voluntarily redeploying attention. A separate phenomenon known as the attentional blink (AB) also follows a similar time course, yet occurs when participants attend to a single spatial location. The present study found that attention can be shifted more quickly than previously estimated and that part of the deficit observed during searches of spatially distinct RSVP streams is due to an AB. The results support some early and late selection accounts for the temporal dynamics of visual attention and suggest different bottlenecks during visual selection. The implications for visual search and visual processing are discussed.     

Eye movements blink the attentional blink

When presented with a sequence of visual stimuli in rapid succession, participants often fail to detect a second salient target, a phenomenon referred as the attentional blink (AB; Raymond, Shapiro, & Arnell, 1992; Shapiro, Raymond, & Arnell, 1997). On the basis of a vast corpus of experiments, several cognitive theories suggest that the blink results from a discrete structuring of attention, sampling information from temporal episodes during which several items can access encoding process (Wyble, Bowman, & Nieuwenstein, 2009; Wyble, Potter, Bowman, & Nieuwenstein, 2011). The objective of this work is to explore the AB when multiple items are presented at the fovea during ocular movements. The authors reasoned that each fixation may cohesively form an episode and hence expected that the blink may vanish within a single fixation. In turn, they expected saccades to accentuate episodic borders and hence shorten the regime of interference when 2 targets are presented fovealy in successive fixations. Evidence is provided in favor of this hypothesis, showing that the blink vanishes when both targets are presented in the core of a single fixation (far from the saccadic boundaries) and that it recovers more rapidly in successive fixations. These studies support current views that episodes should have an effect on the AB and provide evidence that eye movements play an important role in the formation of episodes.     

Visual search is postponed during the attentional blink until the system is suitably reconfigured

J. S. Joseph, M. M. Chun, and K. Nakayama (1997) found that pop-out visual search was impaired as a function of intertarget lag in an attentional blink (AB) paradigm in which the 1st target was a letter and the 2nd target was a search display. In 4 experiments, the present authors tested the implication that search efficiency should be similarly impaired (steeper search slopes at shorter lags). A conventional AB deficit was found, but, contrary to expectations, search slopes were invariant with lag. These results suggest that no search can be carried out during the period of the AB. Instead, the search is postponed until after the 1st target has been processed. The authors conclude that efficient visual search cannot be carried out unless the visual system is configured appropriately for the search task. If the initial configuration is inappropriate, processing of the 2nd target is held in abeyance until the system has been suitably reconfigured.     

Facilitation of local information processing in the attentional blink as indexed by the shooting line illusion

Perception of the second of two rapidly sequential targets is impaired if the temporal lag between them is relatively short. This attentional blink (AB) is said to occur because the first target preoccupies attentional resources, leading to a shortage of attention for, and subsequent failure of judgement of, the second target. In the present study, we examined whether the attention which is preoccupied by the first target carries the common characteristic of spatial attention, that is local facilitation of information processing. To index the facilitation, we presented an attention-sensitive probe known as the shooting line illusion in which observers see a progressively drawn line from the attended end to the other. We found that illusory motion was perceived to emanate from the end where the first target was presented. This result demonstrates the inherently spatial nature of attention, even when it is defined by temporal and symbolic variables.     

Evidence for Distinct Attentional Bottlenecks in Attention Switching and Attentional Blink Tasks

E. Weichselgartner and G. A. Sperling (1987), using rapid serial visual presentation (RSVP), estimated that attention could be moved to a new spatial location within 300-400 ms. H. J. Müller and P. M. Rabbit (1989) used a spatial cuing task and found a similar time course for voluntarily redeploying attention. A separate phenomenon known as the attentional blink (AB) also follows a similar time course, yet occurs when participants attend to a single spatial location. The present study found that attention can be shifted more quickly than previously estimated and that part of the deficit observed during searches of spatially distinct RSVP streams is due to an AB. The results support some early and late selection accounts for the temporal dynamics of visual attention and suggest different bottlenecks during visual selection. The implications for visual search and visual processing are discussed.     

Direct evidence for a role of working memory in the attentional blink

Theories of selective attention often have a central memory component, which is commonly thought to be limited in some way and is thereby a potential bottleneck in the attentional process. There have been only a few attempts to validate this assertion, and they have produced mixed results. This study presents a specific examination of the link between working memory and attention by engaging active rather than passive memory operations. Two experiments are reported that provide evidence for the involvement of working memory in the attentional blink (AB) phenomenon. Memory loads of increasing size had a detrimental effect on attentional performance within the blink-sensitive interval, but not beyond. Speeded response requirements proved to modulate the AB, but were independent from the memory load effect. Theoretical implications for current models of selective attention are discussed.     

The “beam of darkness”: Spreading of the attentional blink within and between objects

When two targets (T1 and T2) are inserted into a rapid serial visual presentation (RSVP) stream of nontargets, observers are impaired at identifying T2 when it is presented within half a second after T1. This transient drop in performance, or attentional blink (AB), has been attributed to a temporary unavailability of task-critical processing resources. In the present study, we investigated how object-based attention modulates the AB, by presenting four synchronized RSVP streams in the corners of two rectangular bars (e.g., one above and one below fixation). The results from four experiments revealed that the AB increased within short temporal lags (of up to ～400 msec) when T2 was presented on the same, rather than a different, bar as T1 (with T1–T2 spatial distance controlled for). Thus, the AB is seen to spread across entire object groupings, suggesting that the spatiotemporal resolution of attention is modulated by global-object information.     

Differences in attentional involvement underlying the perception of distinctive and typical faces

Differences in human faces can be evaluated along a continuum that ranges from 'distinctive' to 'typical.' We examined processing differences between distinctive and typical faces by two attentional tasks that induce attentional blink (AB). Given that AB is believed to reflect temporal or capacity limits of attention, stimuli that survive AB are believed to be associated with greater processing efficiency. In a change-detection task, participants were required to detect changes in the two pairs of faces that were presented in rapid succession. Changes involving the distinctive face of a pair were more likely to be detected than those involving a typical face. In a face-identification task, distinctive faces embedded in a rapid serial visual presentation (RSVP) stream were identified with a greater accuracy than typical faces. Together, our results suggest that distinctive faces are associated with greater processing efficiency and may be explained in terms of perceptual salience, a stimulus dimension known to attract attention.