Individual differences in electrophysiological responses to performance feedback predict AB magnitude

The attentional blink (AB) is observed when report accuracy for a second target (T2) is reduced if T2 is presented within approximately 500 ms of a first target (T1), but accuracy is relatively unimpaired at longer T1–T2 separations. The AB is thought to represent a transient cost of attending to a target, and reliable individual differences have been observed in its magnitude. Some models of the AB have suggested that cognitive control contributes to production of the AB, such that greater cognitive control is associated with larger AB magnitudes. Performance-monitoring functions are thought to modulate the strength of cognitive control, and those functions are indexed by event-related potentials in response to both endogenous and exogenous performance evaluation. Here we examined whether individual differences in the amplitudes to internal and external response feedback predict individual AB magnitudes. We found that electrophysiological responses to externally provided performance feedback, measured in two different tasks, did predict individual differences in AB magnitude, such that greater feedback-related N2 amplitudes were associated with larger AB magnitudes, regardless of the valence of the feedback.     

Relationships between attentional blink magnitude, RSVP target accuracy, and performance on other cognitive tasks

When two masked, to-be-attended targets are presented within approximately half a second of each other, performance on the second target (T2) suffers, relative to when the targets are presented further apart in time or when the first target (T1) can be ignored. This pattern of results is known as the attentional blink (AB). Typically, participants differ with respect to the magnitude of their AB and their overall target accuracy. Despite investigations as to what participant characteristics may influence AB performance (e.g., age, brain damage, or mood state), there has been no focused examination of whether individual differences in cognitive performance measures predict the magnitude of the AB or overall rapid serial visual presentation(RSVP) target accuracy. Our university studentparticipants performed single-target and dual-target RSVP tasks, as well as a selection of cognitive tasks that did not use RSVP presentations, with color, letter, digit, and object stimuli. Overall performance on each of the RSVP targets (T1, T2, and single target) was predicted by speeded manual and vocal identification times to isolated stimuli and by performance with other RSVP targets. However, the magnitude of the AB was predicted only by T1 accuracy, not by any other performance measures. The results suggest that individual differences in AB magnitude do not result from differences in effective RSVP target encoding and are not well explained by varied information-processing abilities.     

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.     

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.     

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.     

Cuing and stimulus probability effects on the P3 and the AB

Two experiments were conducted to investigate the relation between the attentional blink (AB), a deficit in reporting the second of two targets when it occurs 200-500 ms after the first, and the P3 component of the event-related potential. Consistent with the view that the AB reflects a limited ability to consolidate information in working memory and that the P3 reflects working memory updating, increasing the amplitude of the P3 elicited by a first target (T1) by varying T1 probability (Experiment 1) or T1 cue validity (Experiment 2) led to an increase of the AB. Overall, the P3 elicited by T1 was greater when T2 was not identified than when it was. However, the correlation between P3 and AB magnitude across participants was not significant, leaving open the question of how direct the relationship between the P3 and the AB is.     

The attentional blink is not affected by backward masking of T2, T2-mask SOA, or level of T2 impoverishment

Identification of the second of two targets (T2) is impaired when presented shortly after the first (T1). This attentional blink (AB) is thought to arise from a delay in T2 processing during which T2 is vulnerable to masking. Conventional studies have measured T2 accuracy which is constrained by the 100% ceiling. We avoided this problem by using a dynamic threshold-tracking procedure that is inherently free from ceiling constraints. In two experiments we examined how AB magnitude is affected by three masking-related factors: (a) presence/absence of T2 mask, (b) T2-mask stimulus onset asynchrony (SOA), and (c) level of T2 impoverishment (signal-to-noise ratio [SNR]). In Experiment 1, overall accuracy decreased with T2-mask SOA. The magnitude of the AB, however, was invariant with SOA and with mask presence/absence. Experiment 2 further showed that the AB was invariant with T2 SNR. The relationship among mask presence/absence, SOA, and T2 SNR and the AB is encompassed in a qualitative model.     

Concurrency benefits in the attentional blink: Attentional flexibility and shifts of decision criteria

Fundamental limitations in performing multiple tasks concurrently are well illustrated by the attentional blink (AB) deficit, which refers to the difficulty in reporting a second target (T2) when it is presented shortly after a first target (T1). Surprisingly, recent studies have shown that the AB, which is often thought of as a manifestation of capacity limitations in central processing, can be reduced when the AB task is performed simultaneously with concurrent distracting activities. In the present study, we sought to investigate whether such concurrency benefits would also be observed when the AB task was performed concurrently with a central demanding timing task. The AB was reduced under concurrent-task conditions, as compared with single-AB-task conditions, even though T1 performance was unaffected by the concurrent task. Moreover, shifts in decision criteria were found to be associated with the concurrency benefit effect.     

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.     

Dissociating the effects of featural and conceptual interference on multiple target processing in rapid serial visual presentation

Attentional blink (AB) describes the finding that, when subjects attend to a specified target in a rapidly presented visual stream, they show a decreased ability to process a subsequent probe item for up to 600 msec. In the present study, the roles of featural and conceptual interference in the processing of targets and probes in a rapid serial visual presentation stream were examined. In Experiment 1, featurally more complex T + 1 items produced larger AB even when the physical energy of the stimulus (e.g., the number of pixels) was held constant. In Experiment 2, the conceptual category of the T + 1 item affected target identification but not AB magnitude. These result suggest that featural interference is a major determinant of AB magnitude, whereas featural and conceptual interference both affect target identification.     

The role of spatial switching in the attentional blink

The attentional blink (AB) is a well-established paradigm in which identification of a target T2 is reduced shortly after presentation of an earlier target T1. An important question concerns the importance of backward masking during the AB. While task switching has been found to be a strong modulator mediating the AB without any masking of T2, the present study investigated whether spatial switching could similarly produce an AB without masking. Using a spatial AB paradigm in which items appeared at different locations; we found (a) a significant AB without backward masking of T2 but no AB when no distractors followed T2, (b) no evidence for Lag 1 sparing. These findings show that when there is a spatial switch between the targets, presenting the distractor following T2 at the same location than T2 (backward masking) is not a necessary condition for the AB to occur, but T2 has to be followed by surrounding distractors (appearing at different locations than T2). This pattern of data confirms that spatial switching is a robust modulator of the AB, but to a less extent than task switching.     

The attentional blink and lag 1 sparing are nonspatial

The attentional blink (AB) refers to the finding that the perception of the second of two targets (T2) is impaired when presented in close temporal proximity to the first target (T1). An exception to this deficit occurs when T2 immediately follows T1, an effect referred to as lag 1 sparing. So far, it has been unclear whether the AB is location specific or nonspatial in nature. Most demonstrations of an AB across different locations have shown an absence of lag 1 sparing, due to accompanying spatial switch costs. This means that the AB pattern itself may be explained through such switch costs. In this study, to minimize spatial switch costs, attention was made to move continuously across multiple locations by aid of a cue. An AB across different locations was found, including lag 1 sparing. We conclude that the AB and lag 1 sparing are not tied to a location but represent a central deficit, in line with current theory.     

Resting EEG in alpha and beta bands predicts individual differences in attentional blink magnitude

Accuracy for a second target (T2) is reduced when it is presented within 500 ms of a first target (T1) in a rapid serial visual presentation (RSVP) - an attentional blink (AB). There are reliable individual differences in the magnitude of the AB. Recent evidence has shown that the attentional approach that an individual typically adopts during a task or in anticipation of a task, as indicated by various measures, predicts individual differences in the AB deficit. It has yet to be observed whether indices of attentional approach when not engaged in a goal-directed task are also relevant to individual differences in the AB. The current studies investigated individual differences in the AB by examining their relationship with attention at rest using quantitative measures of EEG. Greater levels of alpha at rest were associated with larger AB magnitudes, where greater levels of beta at rest were associated with smaller AB magnitudes. Furthermore, individuals with more beta than alpha demonstrated a smaller AB effect than individuals with more alpha than beta. Our results suggest that greater attentional engagement at rest, when not engaged in a goal-directed task, is associated with smaller AB magnitudes.     

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.     

Voluntary triggering of the first target attenuates the attentional blink

The term attentional blink (AB) refers to a failure in identifying the second of two targets, separated by less than 500?ms, embedded in a rapid succession of nontargets. To examine whether the expectation of the onset of the first target affects the AB, we compared the magnitudes of the AB deficit when participants triggered the appearance of the first target and when the target was presented automatically at some time point, as in traditional AB studies. In Experiment 1, the first target appeared immediately after a participant's voluntary keypress, revealing that the accuracy for identifying the first target increased and that the AB deficit was attenuated. In Experiment 2, the temporal delay between a voluntary keypress and the first-target presentation was manipulated. The results showed that both targets could be reported accurately only when the first target was presented within 300?ms after the action. In Experiment 3, we ruled out an alternative explanation that would attribute the facilitation effect to mere physical movement, by examining the accuracy of target identification when participants voluntarily pressed a key but that action was unrelated to the onset of the first target. Taken together, the results suggest that voluntary action to trigger the onset of a visual target facilitates processing and reduces the subsequent AB deficit when the target appears within 300?ms of the action.     

T1 difficulty and the attentional blink: Expectancy versus backward masking

According to bottleneck models of the attentional blink (AB), first-target (T1) processing difficulty should be related to AB magnitude. Tests of this prediction that have varied T1 difficulty in the context of a standard AB paradigm, however, have yielded mixed results. The present work examines two factors that may mediate the relationship between T1 difficulty and the AB: observer expectancy and backward masking of T1. In two experiments, omission of the backward mask consistently yielded the predicted relationship between T1 difficulty and the AB. In contrast, observer expectancy influenced target identification accuracy but did not mediate the relationship between T1 difficulty and the AB.     

Temporal tuning and attentional gating: Two distinct attentional mechanisms on the perception of rapid serial visual events

We examined the relationship between two different attention limitations on the perception of rapid events: the attentional awakening (AA, an inability to successfully process a target when it appears early on in a rapid stream of events) and the attentional blink (AB, an inability to successfully process a second target when it appears shortly after a first target [T1]). In four experiments, we failed to find a relationship between the magnitudes of these phenomena. Furthermore, we found two manipulations that selectively modulated the magnitude of each effect without altering the magnitude of the second effect: Expected range of possible rapid serial visual presentation lengths modulated the AA (but not the AB), suggesting that the AA reflects an attentional setup cost for perceiving a protracted series of rapid events, whereas the number of possible T1 positions in the stream modulated the magnitude of the AB (but not the magnitude of the AA). Our results suggest that, despite the surface similarities between the two phenomena, different mechanisms are responsible for these two attentional limitations: Whereas the AA reflects a starting cost associated with the time required to temporally tune attention to the stimulus stream, the AB reflects a blocking of undesired stimuli, aimed at protecting consolidation of T1 processing.     

T1 difficulty and the attentional blink: expectancy versus backward masking

According to bottleneck models of the attentional blink (AB), first-target (T1) processing difficulty should be related to AB magnitude. Tests of this prediction that have varied T1 difficulty in the context of a standard AB paradigm, however, have yielded mixed results. The present work examines two factors that may mediate the relationship between T1 difficulty and the AB: observer expectancy and backward masking of T1. In two experiments, omission of the backward mask consistently yielded the predicted relationship between T1 difficulty and the AB. In contrast, observer expectancy influenced target identification accuracy but did not mediate the relationship between T1 difficulty and the AB.     

Revisiting within-modality and cross-modality attentional blinks: effects of target-distractor similarity

When two masked targets (T1 and T2) require attention and are presented within half a second of each other, the report accuracy for T2 is reduced, relative to when the two targets are presented farther apart in time. This effect is known as the attentional blink (AB). Potter, Chun, Banks, and Muckenhoupt (1998) argued that all AB-like effects observed when at least one of the targets was presented outside of the visual modality did not represent true instances of the AB, but instead were artifacts of task-set switching. However, in the Potter et al. experiments the presence or absence of task-set switching opportunities was confounded with the T2 task, as well as the alphanumeric class of T2 with respect to the distractors. In the present experiment, we examine the influence of T1 alphanumeric class, T2 alphanumeric class, and switching operations in a fully crossed design that unconfounds these factors. In contrast to the conclusions of Potter et al., the present results suggest that the T2 alphanumeric class can account for the pattern of ABs observed across conditions, without necessarily implicating a separate switch cost. The implications for theoretical models of the AB and the debate over the validity of cross-modal ABs are discussed.     

Perception of temporal order is impaired during the time course of the attentional blink

Identification accuracy for the second of two target (T2) is impaired when presented shortly after the first (T1). Does this attentional blink (AB) also impair the perception of the order of presentation? In four experiments, three letter targets (T1, T2, T3) were inserted in a stream of digit distractors displayed in rapid serial visual presentation (RSVP), with T3 always presented directly after T2. The T1-T2 lag was varied to assess the perception of T2-T3 temporal order throughout the period of the AB. Factorial manipulation of the presence or absence of distractors before T1 and between T1 and T2 had similar effects on accuracy and on perception of temporal order. It is important to note that perception of temporal order suffered even when accuracy was unimpaired. This pattern of results is consistent with prior-entry theories of the perception of temporal order but not with episodic-integration theories. Simulations based on the Episodic Simultaneous Type, Serial Token (eSTST) model (Wyble, Bowman, & Nieuwenstein, 2009) provided excellent fits to the data except for the condition in which no distractors were presented in the RSVP stream.