Showing papers on "Attentional blink published in 2002"

Made you blink! Contingent attentional capture produces a spatial blink.

Abstract: Previous studies have shown that the capture of attention by an irrelevant stimulus can be eliminated by foreknowledge of the spatial location of the relevant target stimulus. To explore whether spatial certainty is sufficient to eliminate capture, four experiments are reported in which the spatial location of the target is certain but the temporal position is uncertain. Subjects viewed a central rapid serial visual presentation stream in which a target letter was defined by a particular color (e.g., red). On critical trials, irrelevant color singletons appeared in the periphery. In Experiments 1 and 2, peripheral singletons produced a decrement in central target identification that was contingent on the match between the singleton color and the target color. Experiments 3 and 4 provided evidence that this decrement reflected a shift of spatial attention to the location of the distractor. The results suggest that spatial certainty is not sufficient to eliminate attentional capture and that attentional capture can result in a spatial “blink” that is conditional on top-down attentional control settings.

Delayed working memory consolidation during the attentional blink.

Abstract: After the detection of a target (T1) in a rapid stream of visual stimuli, there is a period of 400–600 msec during which a subsequent target (T2) is missed. This impairment in performance has been labeled the attentional blink. Recent theories propose that the attentional blink reflects a bottleneck in working memory consolidation such that T2 cannot be consolidated until after T1 is consolidated, and T2 is therefore masked by subsequent stimuli if it is presented while T1 is being consolidated. In support of this explanation, Giesbrecht & Di Lollo (1998) found that when T2 is the final item in the stimulus stream, no attentional blink is observed, because there are no subsequent stimuli that might mask T2. To provide a direct test of this explanation of the attentional blink, in the present study we used the P3 component of the event-related potential waveform to track the processing of T2. When T2 was followed by a masking item, we found that the P3 wave was completely suppressed during the attentional blink period, indicating that T2 was not consolidated in working memory. When T2 was the last item in the stimulus stream, however, we found that the P3 wave was delayed but not suppressed, indicating that T2 consolidation was not eliminated but simply delayed. These results are consistent with a fundamental limit on the consolidation of information in working memory.

The time course of competition for attention: attention is initially labile.

Abstract: Competition for attention between 2 written words was investigated by presenting the words briefly in a single stream of distractors (Experiment 1) or in different streams (Experiment 2-6), using rapid serial visual presentation at 53 ms/item. Stimulus onset asynchrony (SOA) was varied from 0 to 213 ms. At all SOAs there was strong competition, but which word was more likely to be reported shifted markedly with SOA. At SOAs in the range of 13-53 ms the second word was more likely to be reported, but at 213 ms, the advantage switched to the first word, as in the attentional blink. A 2-stage competition model of attention is proposed in which attention to a detected target is labile in Stage 1. Stage 1 ends when one target is identified, initiating a serial Stage 2 process of consolidation of that target.

When visual marking meets the attentional blink: More evidence for top-down, limited capacity inhibition

Abstract: An attentional blink (AB) paradigm was used to investigate the attentional resources necessary for visual marking. The results showed that distractors presented inside the AB cannot easily be ignored despite participants anticipating a future target display. This supports the hypothesis that attentional resources are required for visual marking. In addition, probe dots were better detected on blinked distractors than on successfully ignored distractors, but only when the task required new items to be prioritized. In a final experiment, a stronger negative carry-over effect on search occurred for targets identical to distractors presented outside rather than inside the AB. This suggests that at least part of the inhibitory processes involved in visual marking are nonspatial. The study of visual selective attention focuses on our visual system’s ability to prioritize certain visual events over others. In brief, efficient prioritization depends on the spatial and temporal properties of, as well as the task constraints surrounding, the visual event. In the present study, we considered the interactions between these spatial and temporal factors. Visual selective attention has a strong spatial component. Typically, visual objects relevant to our behavior ( targets) occupy limited spatial regions in a cluttered visual field filled with numerous irrelevant objects (distractors) that are simultaneously present. Sometimes selection of a target is quite effortless. For instance, Treisman and Gelade (1980) found that observers were very efficient in searching for a blue T in a display filled with brown Ts and green Xs. In this single-feature search task it is as if the unique feature (color) of the target guides selection. Typically, therefore, the number of distractors (the display size) has little or no effect on search reaction times (RTs), creating flat slopes for the Display Size RT search functions. In other tasks, selection may be more effortful. For example, Treisman and Gelade found that search for a green T among brown Ts and green Xs was much less efficient than a single-feature search. In this conjunction search, visual attention cannot be guided by the target because the target is defined only by a combination of features it shares with both distractor types. Instead, it is as if attention has to be shifted around the display in an effortful way until the target is found. Typically, therefore, conjunction-search RTs are dependent on the number of items simultaneously present, resulting in a relatively steep search slope (see Wolfe, 1994, and Wolfe, Cave, & Franzel, 1989; for variations; but see Duncan & Humphreys, 1989, for a different explanation).

Modality-specific auditory and visual temporal processing deficits

Abstract: We studied the attentional blink (AB) and the repetition blindness (RB) effects using an audio-visual presentation procedure designed to overcome several potential methodological confounds in previ...

Dual-Task Attention Deficits in Dysphoric Mood

Abstract: The attentional functioning of nondysphoric, mildly dysphoric, and moderately to severely dysphoric college students was tested using the attentional blink (AB) paradigm. These groups performed equally well at reporting a single target appearing in a rapidly presented stream of stimuli. All groups showed an AB, with report sensitivity for a 2nd target being reduced when the 2 targets were presented less than 0.5 s apart. Nondysphoric and mildly dysphoric participants showed the same size ABs, but the ABs for moderately to severely dysphoric participants were larger and longer. As predicted, the results showed that moderately to severely dysphoric individuals have attentional impairments. These impairments, however, were evident only in the more demanding dual-task condition.

A crossmodal attentional blink between vision and touch

Abstract: 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.

Cross-modality attentional blinks without preparatory task-set switching

Abstract: When two masked targets (T1 and T2), both requiring attention, are presented within half a second of each other, report of the second target is poor, demonstrating an attentional blink (AB). Potter, Chun, Banks, and Muckenhoupt (1998) argued that all previous demonstrations of an AB occurring when one or more targets were presented outside the visual modality did not represent true AB but were, instead, artifactual, resulting from switching of task set. In the present experiments, T1 and T2 modalities were independent and varied randomly from trial to trial, allowing no useful preparatory task-set switching from T1 to T2. However, reliable ABs were observed when both targets were visual, when both targets were auditory, and cross-modally when T2s were visual. Furthermore, the ABs observed for crossmodality visual T2s showed the characteristic U-shaped pattern often found in AB experiments in which two visual targets are used—a pattern that should not be observed under task-set switching conditions. These results provide evidence that cross-modality AB can be found under conditions that do not allow useful preparatory task-set switching.

Blinks of the mind: memory effects of attentional processes.

Abstract: If 2 words are presented successively within 500 ms, subjects often miss the 2nd word. This attentional blink reflects a limited capacity to attend to incoming information. Memory effects were studied for words that fell within an attentional blink. Unrelated words were presented in a modified rapid serial visual presentation task at varying stimulus-onset asynchronies, and attention was systematically manipulated. Subsequently, recognition, repetition priming, and semantic priming were measured separately in 3 experiments. Unidentified words showed no recognition and no repetition priming. However, blinked (i.e., unidentified) words did produce semantic priming in related words. When, for instance, ring was blinked, it was easier to subsequently identify wedding than apple. In contrast, when the blinked word itself was presented again, it was not easier to identify than an unrelated word. Possible interpretations of this paradoxical finding are discussed.

Attentional limitations in processing sequentially presented vibrotactile targets

Abstract: 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.

Emotional stimuli reduce the attentional blink in sub-clinical anxious subjects

Abstract: It has been documented that high anxious subjects process emotional stimuli in a very special way that sometimes has been characterized as an attentional bias toward them. Our main purpose here is to test whether emotional and neutral words would produce different magnitudes of the effect known as attentional blink (AB) on high-trait anxious subjects, but not on low-trait subjects. Participants had to identify the only white word (target 1) in a stream of black words displayed using the Rapid Serial Visual Presentation (RSVP) technique, and detect if a probe word (target 2) is present in the series. The words used as target 1 could be emotional or neutral. The results show that the emotional information reduces the magnitude of the AB only for the high-trait anxiety group. The implications of these results for both theoretical and practical fields are discussed in terms of the subjects high level of automaticity to process emotional information.

Impairment of temporal attention in patients with schizophrenia.

Abstract: Evidence is accumulating that attention impairment is a core cognitive deficit in patients with schizophrenia. Here we investigate whether they are impaired in the temporal deployment of attention. Specifically, we explore how allocation of processing resources at one time point might affect the processing of a subsequent event differently in normal and schizophrenia subjects. Thirty patients and 31 age- and education-matched control subjects participated in a rapid serial visual presentation task, in which two targets (T1 and T2) were presented in rapid succession among a number of distractors. Subjects were required to identify T1 and detect T2. The sensitivity of T2 detection was analyzed with signal detection theory. The results showed that the attentional blink (the impairment in T2 detection following the identification of T1) is increased in magnitude and protracted in the patients. This observation suggests a less efficient mechanism in temporal gating of attention and in processing rapidly changing visual stimuli in schizophrenia patients.

A Comparison Between Schizophrenia Patients and Healthy Controls on the Expression of Attentional Blink in a Rapid Serial Visual Presentation (RSVP) Paradigm

Abstract: The expression of attentional blink (AB) in 24 schizophrenia inpatients was compared to 22 healthy subjects in a dual-target rapid serial visual presentation (RSVP) paradigm in which a sequence of discrete stimuli was presented in rapid succession. Correct identification of the first target led to poorer detection of the second one when they were interspersed by distractors. This second-target deficit constitutes the AB effect, which is most pronounced between 200 and 500 ms after the offset of the first target stimulus and steadily decays as the number of intervening distractors increases. Despite relatively poor performance in terms of target identification within RSVP streams, schizophrenia patients expressed an AB effect that was as clear as that seen in healthy subjects. Moreover, there was evidence for an enhanced AB effect in schizophrenia patients. This outcome contrasts with the robust finding that schizophrenia patients are attenuated in the expression of prepulse inhibition, another paradigm believed to assess attentional control. The present results add to the extensive literature on the nature and specification of attentional dysfunction implicated in schizophrenia.

The relationship between attentional blink and psychological refractory period

Abstract: This study examined the relationship between attentional blink (AB) and psychological refractory period (PRP) using a conventional AB procedure combined with a requirement of speeded responses to the second target (T2). Experiments 1 and 2 showed that, as with PRP, memory retrieval of targets is not a necessary condition for the occurrence of AB in terms of accuracy and that AB occurred in the speed data. Experiment 3 further indicated that the PRP-like speed data were not due to the first target serving as a warning signal that triggered preparation of responses to T2. Experiment 4 manipulated T2 stimulus intensity to be normal or low. Results showed an underadditive interaction between stimulus intensity and lag position in the speed data, whereas an overadditive interaction was found in the accuracy data, suggesting 2 sources of interference leading to AB: the single-channel bottleneck and resource-limited visual-processing capacity.

Loci of signal probability effects and of the attentional blink bottleneck.

Abstract: To investigate the locus of signal probability effects and the influence of stimulus quality on this locus, the authors manipulated probability in Task 2 of a psychological refractory period (PRP) paradigm. The effect was additive with stimulus onset asynchrony (SOA) when the target was not masked but underadditive with decreasing SOA when the target was masked. Even with masking, however, a range of probabilities had effects additive with SOA. The results suggest loci of stimulus probability before the PRP bottleneck as well as at or after the bottleneck. A second issue addressed was the locus of interference in the attentional blink (AB). The AB was larger when the probability of the first of 2 targets was lower. The results lead to the conclusion that one cause of the AB effect is a locus at least as late as the PRP bottleneck.

Objects and Events in the Attentional Blink

Abstract: When two visual targets, T1 and T2, are presented in rapid succession, detection or identification of T2 is almost universally de- graded by the requirement to attend to T1 (the attentional blink , or AB). One interesting exception occurs when T1 is a brief gap in a continu- ous letter stream and the task is to discriminate its duration. One hy- pothesized 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 iden- tification of an identical longer letter T1 was required (Experiment 3), rather than a duration judgment, the AB was reestablished. Direct percep- tual 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 sepa- rating 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 trig- gered only when a new attended event is defined, either when a long pause creates a new perceived stream (Experiment 4) or when atten- tion shifts from the stream to the letter level (Experiment 3). The rapid serial visual presentation (RSVP) attentional blink (AB) paradigm is a well-established means of investigating the temporal limi- tations of visual selective attention (Broadbent & Broadbent, 1987; Ray- mond, Shapiro, & Arnell, 1992; Shapiro, Raymond, & Arnell, 1994). In the standard visual AB paradigm, stimuli are presented individually, at fixation, at a rate of 6 to 20 items/s (Shapiro et al., 1994). Embedded within each stream of rapidly presented stimuli are two targets (T1 and T2) that are differentiated from nontarget distractors in terms of cer- tain visual attributes (e.g., color, duration, identity). For example, the T1 task may require participants to identify a white letter within a stream of nontarget black letters. The T2 task may be to detect a black letter X (differentiated by identity) that is presented in only 50% of trials. In the standard AB paradigm, it is customary to compare performance when both targets are reported ( dual-target condition) with performance when only the second target is reported ( single-target condition). Whereas these conditions are equivalent in terms of visual information, they dif- fer in terms of what the participant is required to report and thus what must be attended (Raymond et al., 1992). The amount of interference caused by attending to T1 can then be measured by contrasting T2 per- formance in the two conditions. The critical manipulation necessary to reveal the AB is the tempo- ral position of T2 relative to T1 in the RSVP stream. T2 is presented at a range of serial positions (stimulus onset asynchrony, or SOA, usu-

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

Abstract: 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.

Temporal processing of global and local information varies with global precedence.

Abstract: The concept of global precedence, which suggests that the global aspect of a scene is processed more rapidly than local details, was examined using the attentional blink paradigm. Eighteen adult subjects observed multiple sequences of complex global−local letter figures to see whether the attentional blink duration would be affected by the visual angle size of the stimulus. Within each sequence, the subject was directed to identify either a global or local red target letter and to detect whether a global or local probe letter (X) was presented in the sequence following the target letter. Stimuli were presented at three different sizes. Results showed significantly higher probe detection rates for global probes than for local at small stimulus sizes. However, using large stimulus sizes, mean correct probe detection was sig­nificantly higher in conditions requiring local attention compared to global. No significant difference in probe detection performance was observed between global and local conditions at medium stimulus sizes. The results suggest that the rate of visual information processing varies according to the visual angle of the particular information. The results support the suggestion that the precedence of information is an important factor in the temporal processing of global−local information.

Separating perception time from response time: the slope transition paradigm.

Abstract: This paper describes the slope transition paradigm (STP), a variant of rapid serial visual presentation (RSVP) that separates early (perceptual) processing time from total response time. The paradigm is based on a very simple idea: provide varying amounts of time for perceptual processing and find the moment when the subject begins to waste time waiting for more data. That moment is a measure of how much time was actually needed. The method was used in two experiments. Results are discussed in relation to set-size effects, perceptual capacity limits, attentional dwell times, and some related neurophysiological findings. The method appears to tap aspects of information processing that differ from those tapped in studies of the psychological refractory period, the attentional blink, and repetition blindness.

Are musicians listening to sounds in a different way than non-musicians?

Abstract: Response of musicians and non musicians to a target sound in the presence of simultaneous distracters was compared. The attentuation of auditory attentional blink was examined in the group of musicians. The results showed that the musicians have an attenuated auditory attentional blink compared to non-musicians and the magnitude of the auditory attentional blink was significantly reduced for this group.

Timbral segregation of signals and the auditory attentional blink

Abstract: The nature of the auditory attentional blink (AAB) was studied. A blink occurs when two-to-be-attended (TBA) signals are presented in rapid succession and are reported as a single signal. The results suggest that the ABB is robust across streaming tasks, although further manipulation of streaming tasks may be necessary to determine this with more certainty.