Effect of distractor sounds on the auditory attentional blink

Four experiments were conducted to determine whether or not the presence and placement of distractors in a rapid serial auditory stream has any influence on the emergence of the auditory attentional blink (AB). Experiment 1 revealed that the presence of distractors is necessary to produce the auditory AB. In Experiments 2 and 3, the auditory AB was reduced when the distractor immediately following the probe was replaced by silence but not when the distractor following the target was replaced by silence. Finally, in Experiment 4, only a very small auditory AB was found to remain when all distractors following the probe were replaced by silence. These results suggest that the auditory AB is affected both by the overwriting of the probe by the distractors following it and by a reduction in discriminability generated by all of the distractors presented in the sequence.     

Auditory attentional blink: masking the second target is necessary, delayed masking is sufficient.

When two target items (T1 and T2) are presented in rapid succession among fillers, processing T2 is often impaired. This phenomenon is known as the attentional blink (AB). Within the visual modality, this second-target deficit generally occurs only if T2 is masked by a trailing item. The current study was designed to examine whether masking of T2 also plays a critical role in the auditory AB. Results showed a reliable AB effect even when the item following T2 was replaced by silence. However, the AB deficit was abolished when T2 was the last presented stimulus. Our results suggest that, as in vision, T2 masking is necessary for the AB to take place in audition, but that masking is effective even when delayed, providing evidence that the phenomenon shares some functional mechanisms across sensory modalities.     

The absence of an auditory-visual attentional blink is not due to echoic memory

The second of two targets is often missed when presented shortly after the first target--a phenomenon referred to as the attentional blink (AB). Whereas the AB is a robust phenomenon within sensory modalities, the evidence for cross-modal ABs is rather mixed. Here, we test the possibility that the absence of an auditory-visual AB for visual letter recognition when streams of tones are used is due to the efficient use of echoic memory, allowing for the postponement of auditory processing. However, forcing participants to immediately process the auditory target, either by presenting interfering sounds during retrieval or by making the first target directly relevant for a speeded response to the second target, did not result in a return of a cross-modal AB. Thefindings argue against echoic memory as an explanation for efficient cross-modal processing. Instead, we hypothesized that a cross-modal AB may be observed when the different modalities use common representations, such as semantic representations. In support of this, a deficit for visual letter recognition returned when the auditory task required a distinction between spoken digits and letters.     

Attentional limitations in processing sequentially presented vibrotactile targets

In seven experiments, participants experienced rapid, serially presented streams of vibrations and responded to specific targets in the streams. In visual (and sometimes auditory) streams presented in this manner, it is typical to find a deficit in reporting the second of two targets when both must be reported and the second appears within a short temporal interval of the first, but not when identical displays are presented but only the second target must be reported (e.g., the attentional blink, or AB). This conventional AB pattern was found in the last experiment, in which judgments were about target location. However in the first six experiments reported here, in which judgments were about frequency, intensity, duration, or location of targets, accuracy was dependent on target separation regardless of whether or not the first target was reported. This unconventional pattern could represent an AB if the first target was attended even when it was not reported. The evidence for this claim and an alternative possibility that location judgments are especially sensitive to attention manipulations are discussed.     

Mere presence of distractors: Another determining factor for the attentional blink1

Abstract: When two visual targets are presented in rapid succession, perception of the second target is deteriorated if the temporal lag between the two targets is short (0–300 ms). This ‘attentional blink’ (AB) phenomenon has been believed to occur only when the second target is followed by a backward mask or when there is a task switching between two targets. The present study revealed another determining factor for the occurrence of the AB, the presence or absence of a distractor stream. Five experiments examined the effect of possible confounding factors in the extant literature and suggested that the mere presence of a distractor stream affects the processing of targets even when the observers tried to ignore them, resulting in a processing delay. This effect is discussed in a model of AB deficit in terms of decay of the second target's representation.     

Object file continuity and the auditory attentional blink

Three experiments were designed to investigate the causes of the auditory attentional blink (AB). Experiments 1A and 1B revealed that there was a larger auditory AB when the target and the distractors were different in two attributes than when they were different in only one attribute. Experiments 2A and 2B showed that for pure-tone distractor sequences, there were small auditory AB deficits when both the target and the probe were different from the distractors in two attributes or in one attribute; however, for pulse distractor sequences, there was a large auditory AB when both the target and the probe were different from the distractors in one attribute, but not when they were different in two attributes. Experiments 3A and 3B revealed that regardless of the relationship of the target to the subsequent distractors, a large AB was generated if it was the first sound in a sequence. Moreover, only a very small AB was apparent when the distractors following the probe were replaced by silence. These results indicated that the auditory AB is affected by both the requirement of creating and consolidating a new object file for the target and the overwriting of the probe by the distractors following it.     

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.     

Delayed masking and the auditory attentional blink: A test for retrieval competition and bottleneck models

The attentional blink (AB) corresponds to a transient deficit in reporting the second (T2) of two targets embedded in a rapid sequence of distractors. The retrieval competition (Shapiro, Raymond & Arnell, 1994) and bottleneck models (Chun & Potter, 1995; Jolicoeur, 1998) predict the attenuation of the deficit with the extension of the delay between T2 and its mask. This prediction was tested using auditory sequences of nonverbal stimuli in which the T2-mask interval was systematically varied. The magnitude of the auditory AB diminished with the lengthening of the interval from 50 to 150 ms while no time-locked deficit was observed with the longest (350 ms) and the shortest (10 ms) intervals. These results suggest that presenting a mask after T2 is not sufficient to produce an auditory AB: The mask must be perceivable as an auditory event distinct from the target and occur before T2 consolidation. The present study also provides evidence that as in vision, AB deficits take place in the auditory domain when T2 is masked by interruption but not by integration. Our findings are best accounted for in terms of bottlenecked processing limitations.     

Attentional blink and attentional capture: endogenous versus exogenous control over paying attention to two important events in close succession

Identification of the second of two targets is impaired if it is presented less than about 500 msec after the first This attentional blink (AB) occurs under dual-task conditions in which observers are required to report both targets. AB magnitude has been estimated by subtracting the accuracy scores in the dual task from the corresponding scores in a single task in which observers are instructed to ignore the first target. Experiment 1 showed this procedure to be inappropriate, because the first target cannot be ignored. The remaining three experiments elaborated on this finding andrevealed separate endogenous and exogenous sources of the second-target deficit. A parallel was drawn between the AB deficit and the deficit observed in attentional capture. Both types of deficit can be explained on the basis of a hybrid input-filtering model in which endogenous and exogenous factors are subserved by different pathways.     

The attentional blink is not a unitary phenomenon

Identification of the second of two targets is impaired if it is presented less than about 500 ms after the first. Three models of this second-target deficit, known as attentional blink (AB), were compared:resource-depletion, bottleneck, and temporary loss of control (TLC). Five experiments, in which three sequential targets were inserted in a stream of distractors, showed that identification accuracy for the leading target depended on an attentional switch whose magnitude varied with distractor–target similarity. In contrast, accuracy for the trailing target depended on similarity between the target and the trailing mask. These results strongly suggest that the AB is not a unitary phenomenon. Resource-depletion was ruled out as a viable account. The effect of attentional switching was handled naturally by the TLC model, while bottleneck models offered the best account of the effect of backward masking.     

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.     

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.     

Surprise-induced blindness: a stimulus-driven attentional limit to conscious perception

The cost of attending to a visual event can be the failure to consciously detect other events. This processing limitation is well illustrated by the attentional blink paradigm, in which searching for and attending to a target presented in a rapid serial visual presentation stream of distractors can impair one's ability to detect a second target presented soon thereafter. The attentional blink critically depends on 'top-down' attentional settings, for it does not occur if participants are asked to ignore the first target. Here we show that 'bottom-up' attention can also lead to a profound but ephemeral deficit in conscious perception: Presentation of a novel, unexpected, and task-irrelevant stimulus virtually abolishes conscious detection of a target presented within half a second after the 'Surprise' stimulus, but only for its earliest occurrences (generally 1 to 2 presentations). This powerful but short-lived deficit contrasts with a milder but more enduring form of attentional capture that accompanies singleton presentations in rapid serial visual presentations. We conclude that the capture of stimulus-driven attention alone can limit explicit perception.     

Sources of interference in the attentional blink: target-distractor similarity revisited

Observers monitored streams of words or letters (10 items/sec) for one or two targets. An attentional blink (AB) effect was observed in which identification of the first target temporarily impaired identification of the second target. Target identification was impaired when the distractors were composed of either letters or false-font characters (cf. Maki, Couture, Frigen, & Lien, 1997). An asymmetrical AB effect was observed with letters and mathematical symbols; the AB effect was largest for symbol targets and letter distractors. The characters used in these experiments were rated on their meaningfulness, familiarity, and other stimulus properties. The rating data showed that pixel density best accounted for the asymmetrical target-distractor similarity effects. Modulation of the AB effect by target-distractor similarity appears to result partly from low-level masking. But masking effects may be reduced by attentional capture by target features.     

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.     

A crossmodal attentional blink between vision and touch

There is currently a great deal of interest regarding the possible existence of a crossmodal attentional blink (AB) between audition and vision. The majority of evidence now suggests that no such crossmodal deficit exists unless a task switch is introduced. We report two experiments designed to investigate the existence of a crossmodal AB between vision and touch. Two masked targets were presented successively at variable interstimulus intervals. Participants had to respond either to both targets (experimental condition) or to just the second target (control condition). In Experiment 1, the order of target modality was blocked, and an AB was demonstrated when visual targets preceded tactile targets, but not when tactile targets preceded visual targets. In Experiment 2, target modality was mixed randomly, and a significant crossmodal AB was demonstrated in both directions between vision and touch. The contrast between our visuotactile results and those of previous audiovisual studies is discussed, as are the implications for current theories of the AB.     

Attentional control in the attentional blink is modulated by odor

Increasing evidence suggests that `aromas have distinctive effects on the allocation of attention in space: Arousing olfactory fragrances (e.g., peppermint) are supposed to induce a more focused state, and calming olfactory fragrances (e.g., lavender) a broader attentional state. Here, we investigate whether odors have similar effects on the allocation of attention in time. Participants performed the attentional blink (AB) task, known to produce a deficit in reporting the second of two target stimuli presented in close succession in a rapid sequence of distractors, while being exposed to either a peppermint or a lavender aroma. In two experiments using a between-subjects and a within-subjects design, respectively, we show that the two odors have specific effects on attentional control: As compared with the calming lavender aroma, the arousing peppermint condition yielded a larger AB. Our results demonstrate that attentional control is systematically modulated by factors that induce a more or a less distributed state of mind.     

Task- and location-switching effects on visual attention

In two experiments, we examined the effects of task and location switching on the accuracy of reporting target characters in an attentional blink (AB) paradigm. Single-character streams were presented at a rate of 100 msec per character in Experiment 1, and successive pairs of characters on either side of fixation were presented in Experiment 2. On each trial, two targets appeared that were either white letters or black digits embedded in a stream of black letter distractors, and they were separated by between zero and five items in the stream (lags 1-6). Experiment 1 showed that report of the first target was least accurate if it immediately preceded the second target and if the two targets were either both letters or both digits (task repetition cost). Report of the second target was least accurate if one or two distractors intervened between the two targets (the U-shaped AB lag effect) and if one target was a letter and the other a digit (task switch cost). Experiment 2 added location uncertainty as a factor and showed similar effects as Experiment 1, with one exception. Lag 1 sparing (the preserved accuracy in reporting the second of two targets if the second immediately follows the first) was completely eliminated when the task required attention switching across locations. Two-way additive effects were found between task switching and location switching in the AB paradigm. These results suggests separate loci for their attentional effects. It is likely that the AB deficit is due mainly to central memory limitations, whereas location-switching costs occur at early visual levels. Task-switching costs occur at an intermediate visual level, since the present task switch involved encoding differences without changes in stimulus-response mapping rules (i.e., the task was character identification for both letters and digits).