The attentional blink is susceptible to concurrent perceptual processing demands

In a rapid serial visual presentation stream processing of a first target (T1) impairs detection or identification of a second target (T2) that appears within 500 ms after T1. This effect characterizes the so-called attentional blink (AB). To evaluate contemporary information-processing accounts of the AB phenomenon in terms of the underlying processing mechanisms the present study examined the potential influence of Task 1 difficulty on the AB effect. To this end, T1 contrast and T1 response requirements were systematically varied across four experiments. Experiment 1 ruled out a mere sensory basis of the contrast manipulation on T2 performance. When only T2 had to be reported (Experiment 2) an AB effect occurred that was slightly modulated by T1 contrast. When report of both T1 and T2 was required in a standard AB task (Experiment 3), the magnitude of the AB depended to a larger extent on stimulus contrast, and it increased further when speeded T1 choice responses were additionally required (Experiment 4). On the basis of the present impact of Task 1 difficulty on the AB effect we conclude that processing limitations cause the AB phenomenon. We discuss such limitations in terms of perceptual (T1 consolidation) and central (response selection) bottleneck processes.     

Effects of phonological length on the attentional blink for words

The authors tested whether the attentional blink (AB), a deficit in the ability to report a second target appearing within half a second of a first target, may reflect limitations for consolidating visual stimuli into working memory and awareness. Previous research has shown that people are severely limited in the rate that they can identify and report visual events presented in rapid succession. Word length was examined, a variable known to affect verbal working memory. Experiment 1 showed that the AB was modulated by the phonological length of the first target. Phonologically longer pseudowords triggered larger blink deficits. Experiment 2 also demonstrated the word-length effect on the AB using real-world stimuli, anagrams, that controlled for low-level visual differences between conditions. These data support proposals that the AB reflects a difficulty in consolidating information into working memory.     

No commonality between attentional capture and attentional blink

Visual search for a unique target is impaired when a salient distractor is presented (attentional capture). This phenomenon is said to occur because attention is diverted to a distractor before it reaches the target. Similarly, perception of the second of two targets embedded in a rapid stream of nontargets is impaired, suggesting attentional deprivation due to the processing of the first target (attentional blink). We examined whether these phenomena emerge from a common underlying attentional mechanism by using correlation studies. If these phenomena share a common foundation, the magnitude of these deficits should show within-subject correlations. Participants (N?=?135) revealed significant attentional deficits during spatial and temporal capture and the attentional blink tasks. However, no significant correlation was found among these tasks. Experiment 2 (N?=?95) replicated this finding using the same procedure as that used in Experiment 1 but included another attentional blink task that required spatial switching between the two targets. Strong correlations emerged only between the two attentional blink tasks (with/without spatial switching). The present results suggest that attentional deficits during spatial and temporal capture and the attentional blink tasks reflect different aspects of attention.     

Object file continuity predicts attentional blink magnitude

When asked to identify targets embedded within a rapid consecutive stream of visual stimuli, observers are less able to identify the second target (T2) when it is presented within half a second of the first (T1); this deficit has been termed the attentional blink (AB). Rapid serial visual presentation methodology was used to investigate the relationship between the AB and object files (episodic representations implicated in object identification and perceptual constancy). An inverse linear relationship was found between the degree of object file continuity and AB magnitude. An important locus of object file continuity was the intervening stream items between T1 and T2. The results are discussed in terms of the heuristic of the object file to preserve limited attentional capacity.     

New objects,not new features,trigger the attentional blink

When two different targets must be selected from a rapid serial visual presentation (RSVP) of images, perception of the second target will be markedly reduced if it is presented within about a half second of the first. Known as the attentional blink (AB), this effect reflects temporal limitations in attentional processes enabling awareness of image representations. I tested whether these limitations occur at an object or feature level of processing by presenting (in RSVP) multiple images of the same (old) object depicted in different orientations. Targets were defined by new features added either to this or to a new object. When the first target feature appeared on the old object, no AB effects were found even when the second target was a new object. When a new object carried the first target feature, an AB effect was found even when the second target feature appeared on the same "new" object. The AB appears to reflect limitations in the creation of new object representations, rather than temporal limitations of awareness per se.     

Simultaneous and preceding sounds enhance rapid visual targets: Evidence from the attentional blink

Presenting two targets in a rapid visual stream will frequently result in the second target (T2) being missed when presented shortly after the first target (T1). This so-called attentional blink (AB) phenomenon can be reduced by various experimental manipulations. This study investigated the effect of combining T2 with a non-specific sound, played either simultaneously with T2 or preceding T2 by a fixed latency. The reliability of the observed effects and their correlation with potential predictors were studied. The tone significantly improved T2 identification rates regardless of tone condition and of the delay between targets, suggesting that the crossmodal facilitation of T2 identification is not limited to visual-perceptual enhancement. For the simultaneous condition, an additional time-on-task effect was observed in form of a reduction of the AB that occurred within an experimental session. Thus, audition-driven enhancement of visual perception may need some time for its full potential to evolve. Split-half and test-retest reliability were found consistently only for a condition without additional sound. AB magnitude obtained in this condition was related to AB magnitudes obtained in both sound conditions. Self-reported distractibility and performance in tests of divided attention and of cognitive flexibility correlated with the AB magnitudes of a subset but never all conditions under study. Reliability and correlation results suggest that not only dispositional abilities but also state factors exert an influence on AB magnitude. These findings extend earlier work on audition-driven enhancement of target identification in the AB and on the reliability and behavioural correlates of the AB.     

Repetition blindness is immune to the central bottleneck

Theattentional blink (AB) andrepetition blindness (RB) phenomena refer to subjects’ impaired ability to detect the second of two different (AB) or identical (RB) target stimuli in a rapid serial visual presentation stream if they appear within 500 msec of one another. Despite the fact that the AB reveals a failure of conscious visual perception, it is at least partly due to limitations at central stages of information processing. Do all attentional limits to conscious perception have their locus at this central bottleneck? To address this question, here we investigated whether RB is affected by online response selection, a cognitive operation that requires central processing. The results indicate that, unlike the AB, RB does not result from central resource limitations. Evidently, temporal attentional limits to conscious perception can occur at multiple stages of information processing.     

An attentional blink for sequentially presented targets: Evidence in favor of resource depletion accounts

Several accounts of the attentional blink (AB) have postulated that this dual-target deficit occurs because of limited-capacity attentional resources being devoted to processing the first target at the expense of the second (resource depletion accounts; e.g., Chun & Potter, 1995). Recent accounts have challenged this model (e.g., Di Lollo, Kawahara, Ghorashi, & Enns, 2005; Olivers, van der Stigchel, & Hulleman, 2007), proposing instead that the AB occurs because of subjects’ inability to maintain appropriate levels of attentional control when targets are separated by distractors. Accordingly, the AB is eliminated when three targets from the same attentional set are presented sequentially in a rapid serial visual presentation (RSVP) stream. However, under such conditions poorer identification of the first target is typically observed, hinting at a potential trade-off between the first and subsequent target performances. Consistent with this hypothesis, the present study shows that an AB is observed for successive targets from the same attentional set in an RSVP stream when the first target powerfully captures attention. These results suggest that resource depletion contributes significantly to the AB.     

Different attentional blink tasks reflect distinct information processing limitations: an individual differences approach

To study the temporal dynamics and capacity-limits of attentional selection and encoding, researchers often employ the attentional blink (AB) phenomenon: subjects' impaired ability to report the second of two targets in a rapid serial visual presentation (RSVP) stream that appear within 200-500 ms of one another. The AB has now been the subject of hundreds of scientific investigations, and a variety of different dual-target RSVP paradigms have been employed to study this failure of consciousness. The three most common are those where targets are defined categorically from distractors; those where target definition is based on featural information; and those where there is a set switch between T1 and T2, with the first target typically being featurally defined and T2 requiring a detection or discrimination judgment (probe task). An almost universally held assumption across all AB theories is that these three tasks measure the same deficit; however here, using an individual differences approach, we demonstrate that AB magnitude is only related across categorical and featural tasks. Thus, these paradigms appear to reflect a distinct cognitive limitation from that observed under set-switch conditions.     

Memory search for the first target modulates the magnitude of the attentional blink

The resolution of temporal attention is limited in a manner that makes it difficult to identify two targets in short succession. This limitation produces the phenomenon known as the attentional blink (AB), in which processing of a first target (T1) impairs identification of a second target (T2). In the AB literature, there is broad agreement that increasing the time it takes to process T1 leads to a larger AB. One might, therefore, predict that increasing the number of possible T1 identities, or target set, from 1 to 16 would lead to a larger AB. We were surprised to find that this manipulation of T1 difficulty had no influence on AB magnitude. In subsequent experiments, we found that AB magnitude interacts with T1 processing time only under certain circumstances. Specifically, when the T1 task was either well masked or had to be completed online, we found a reliable interaction between AB magnitude and the target set size. When neither of these conditions was fulfilled, there was no interaction between target set size and the AB. Previous research found that when the target set changes from trial to trial, trials with more possible targets elicited a larger AB. In the present study, the target set is held constant, reducing the demands on working memory. Nevertheless, AB magnitude still interacts with target set size, as long as the T1 task cannot be processed offline. Thus, the act of searching memory delays subsequent processing, even when the role of working memory has been minimized.     

The more your mind wanders,the smaller your attentional blink: An individual differences study

The present studies investigate the hypothesis that individuals who frequently report experiencing episodes of mind wandering do so because they under-invest attentional/executive resources in the external environment. Here we examined whether self-reported instances of mind wandering predict the magnitude of the “attentional blink” (AB) in a rapid serial visual presentation (RSVP) task, since a prominent view is that the AB derives from an over-investment of attention in the information stream. Study 1 demonstrates that subjective reports of mind wandering in a sustained attention task have a negative predictive relation with respect to the magnitude of the AB measured in a subsequent RSVP task. In addition, using the Spontaneous and Deliberate Mind Wandering Questionnaire in Study 2, we were again able to show that trait-level mind wandering in everyday life negatively predicts AB magnitude. We suggest that mind wandering may be the behavioural outcome of an adaptive cognitive style intended to maximize the efficient processing of dynamic and temporally unpredictable events.     

Two noncontiguous locations can be attended concurrently: Evidence from the attentional blink

When two targets (T1 and T2) are inserted in a rapid stream of visual distractors (RSVP), detection/ identification accuracy of T2 is impaired at intertarget lags shorter than about 500 msec. This phenomenon, the attentional blink (AB), has been regarded as a hallmark of the inability of the visual system to process multiple items. Yet, paradoxically, the AB is much reduced when T2 is presented directly after T1 (known aslag-1 sparing). Because lag-1 sparing is said to depend on observers’ spatial attention being set to process the first target, we predicted that if observers are set to monitor two RSVP streams, they could process more than two items; that is, two instances of lag-1 sparing would be obtained concurrently. The results of three experiments indicated that this was the case. When observers searched for two targets in each of two synchronized RSVP streams, lag-1 sparing occurred concurrently in both streams. These results suggest that the visual system can handle up to four items at one moment under RSVP circumstances.     

Rapid serial visual distraction: task-irrelevant items can produce an attentional blink

When two sequential targets (T1 and T2) are presented within about 600 msec, perception of the second target is impaired. This attentional blink (AB) has been studied by means of two paradigms: rapid serial visual presentation (RSVP), in which targets are embedded in a stream of central distractors, and the two-target paradigm, in which targets are presented eccentrically without distractors. We examined the role of distractors in the AB, using a modified two-target paradigm with a central stream of task-irrelevant distractors. In six experiments, the RSVP stream of distractors substantially impaired identification of both T1 and T2, but only when the distractors shared common characteristics with the targets. Without such commonalities, the distractors had no effect on performance. This points to the subjects' attentional control setting as an important factor in the AB deficit and suggests a conceptual link between the AB and a form of nonspatial contingent capture attributable to distractor processing.     

No commonality between attentional capture and attentional blink

Visual search for a unique target is impaired when a salient distractor is presented (attentional capture). This phenomenon is said to occur because attention is diverted to a distractor before it reaches the target. Similarly, perception of the second of two targets embedded in a rapid stream of nontargets is impaired, suggesting attentional deprivation due to the processing of the first target (attentional blink). We examined whether these phenomena emerge from a common underlying attentional mechanism by using correlation studies. If these phenomena share a common foundation, the magnitude of these deficits should show within-subject correlations. Participants (N = 135) revealed significant attentional deficits during spatial and temporal capture and the attentional blink tasks. However, no significant correlation was found among these tasks. Experiment 2 (N = 95) replicated this finding using the same procedure as that used in Experiment 1 but included another attentional blink task that required spatial switching between the two targets. Strong correlations emerged only between the two attentional blink tasks (with/without spatial switching). The present results suggest that attentional deficits during spatial and temporal capture and the attentional blink tasks reflect different aspects of attention.     

Negative attentional set in the attentional blink: control is not lost

The attentional blink (AB) refers to the finding that performance on the second of two targets (T1 and T2) in a rapidly presented stimulus stream is impaired when the targets are presented within 200-500 ms. This study investigates whether a negative attentional set, a form of top-down control, has an additional detrimental effect, and whether its influence is modulated by task demands. A negative attentional set was elicited through presentation of a pre-T1 distractor (D1), which belonged to the same category as T2. The presence of D1 impaired T2 performance, and this negative effect was generally larger inside than outside the AB. Moreover, this D1 effect remained constant or was augmented when the demand on T1 processing was enhanced. These findings demonstrate that a negative attentional set is maintained even though the central system is engaged in the in-depth processing of T1 during the AB.     

Objects and events in the attentional blink

When two visual targets, T1 and T2, are presented in rapid succession, detection or identification of T2 is almost universally degraded by the requirement to attend to T1 (the attentional blink, or AB). One interesting exception occurs when T1 is a brief gap in a continuous letter stream and the task is to discriminate its duration. One hypothesized explanation for this exception is that an AB is triggered only by attention to a patterned object. The results reported here eliminate this hypothesis. Duration judgments produced no AB whether the judged duration concerned a short gap in the letter stream (Experiment 1) or a letter presented for slightly longer than others (Experiment 2). When identification of an identical longer letter T1 was required (Experiment 3), rather than a duration judgment, the AB was reestablished. Direct perceptual judgments of letter streams with gaps embedded showed that whereas brief gaps result in the percept of a single, briefly hesitating stream, longer gaps result in the percept of two separate streams with a separating pause. Correspondingly, an AB was produced in Experiment 4, when participants were required to judge the duration of longer T1 gaps. We propose that, like spatially separated objects, temporal events are parsed into discrete, hierarchically organized events. An AB is triggered only when a new attended event is defined, either when a long pause creates a new perceived stream (Experiment 4) or when attention shifts from the stream to the letter level (Experiment 3).     

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.     

Data-limited manipulations of T1 difficulty modulate the attentional blink.

When two targets are embedded in a temporal stream of distractors, second-target identification is initially impaired and then gradually improves as intertarget interval lengthens (attentional blink; AB). According to bottleneck models of the AB, difficulty of first-target processing should modulate the magnitude of the second-target deficit. To test this, we examined whether a data-limited manipulation of T1 difficulty (forward masking) would modulate AB magnitude. In two experiments, we show that data-limited manipulations of T1 difficulty do affect the AB, so long as T1 is not masked by an immediately trailing distractor. When such a trailing item is present, the relationship between T1 difficulty and the AB disappears.     

Neither backward masking of T2 nor task switching is necessary for the attentional blink

Identification of the second of two targets (T1, T2, inserted in a stream of distractors) is impaired when presented within 500 ms after the first (attentional blink, AB). Barring a T1-T2 task-switch, it is thought that T2 must be backward-masked to obtain an AB (Giesbrecht &; Di Lollo, Journal of Experimental Psychology: Human Perception and Performance, 24, 1454-1466, 1998). We tested the hypothesis that Giesbrecht &; Di Lollo's findings were vitiated by ceiling constraints arising from either response scale (experiment 1) or data limitations (experiment 2). In experiment 1, digit-distractors were replaced with pseudoletters to increase task difficulty, bringing performance below ceiling. An AB occurred without backward masking of T2. In experiment 2, a ceiling-free procedure estimated the number of noise dots needed for 80% T2 identification. An AB was revealed: fewer noise dots were required during the AB period than outside it. Both outcomes confirm that an AB can be obtained without either masking of T2 or task switching.     

The perceptual wink model of non-switching attentional blink tasks

The attentional blink (AB) is a temporary deficit for a second target (T2) when that target appears after a first target (T1). Although sophisticated models have been developed to explain the substantial AB literature in isolation, the current study considers how the AB relates to perceptual dynamics more broadly. We show that the time-course of the AB is closely related to the time course of the transition from positive to negative repetition priming effects in perceptual identification. Many AB tasks involve a switch between a T1 defined in one manner and a T2 defined in a different manner. Other AB tasks are non-switching, with all targets belonging to the same well-known category (e.g., letter targets versus number distractors) or sharing the same perceptual feature. We propose that these non-switching AB tasks reflect perceptual habituation for the target-defining attribute; thus, a ‘perceptual wink’, with perception of one attribute (target identity) undisturbed while perception of another (target detection) is impaired. On this account, the immediate benefit following T1 (lag-1 sparing) reflects positive repetition priming and the subsequent deficit (the blink) reflects negative repetition priming for the realization that a target occurred. In developing the perceptual wink model, we extended the nROUSE model of perceptual priming to explain the results of two new experiments combining the AB and identity repetitions. This establishes important connections between non-switching AB tasks and perceptual dynamics.