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

When 2 different visual targets presented among different distracters in a rapid serial visual presentation (RSVP) are separated by 400 ms or less, detection and identification of the 2nd targets are reduced relative to longer time intervals. This phenomenon, termed the attentional blink (AB), is attributed to the temporary engagement of a limited-capacity attentional system by the 1st target, which reduces resources available for processing the 2nd target. Although AB has been reliably obtained with many stimulus types, it has not been found for faces (E. Awh et al., 2004). In the present study, the authors investigate the underpinnings of this immunity. Unveiling circumstances in which AB occurs within and across faces and other categories, the authors demonstrate that a multichannel model cannot account for the absence of AB effects on faces. The authors suggest instead that perceptual salience of the face within the distracters' series as well as the available resources determine whether or not faces are blinked in RSVP. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Parameterizing the attentional blink effect.

The attentional blink effect (AB) is used to examine the limits of attention in dual-task paradigms. However, since the effect is nonlinear, it is sometimes difficult to characterize the results. Furthermore, it is difficult to assess the significance of the effect between groups because the results are highly variable both within and across subjects. In this paper, we propose a method to quantify four characteristics of the AB curve: the minimum performance, the amplitude between the minimum and the asymptotic performance, the amount of Lag-1 sparing, and the width of the effect. The method, based on curve fitting, allows easier comparisons of the results across experiments, can test only one characteristic at a time, and yields more powerful statistical tests. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Unmasking the attentional blink.

When asked to identify 2 visual targets (T1 and T2 for the 1st and 2nd targets, respectively) embedded in a sequence of distractors, observers will often fail to identify T2 when it appears within 200-500 ms of T1--an effect called the attentional blink. Recent work shows that attention does not blink when the task is to encode a sequence of consecutive targets, suggesting that distractor interference plays a causal role in the attentional blink. Here, however, the authors show that an attentional blink occurs even in the absence of distractors, with 2 letter targets separated by a blank interval. In addition, the authors found that the impairment for identification of the 2nd of 2 targets separated by a blank interval is substantially attenuated either when the intertarget interval is filled with additional target items or when the 2nd target is precued by an additional target. These findings show that the root cause of the blink lies in the difficulty of engaging attention twice within a short period of time for 2 temporally discrete target events. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Attentional capture by emotional stimuli is modulated by semantic processing.

The attentional blink paradigm was used to examine whether emotional stimuli always capture attention. The processing requirement for emotional stimuli in a rapid sequential visual presentation stream was manipulated to investigate the circumstances under which emotional distractors capture attention, as reflected in an enhanced attentional blink effect. Emotional distractors did not cause more interference than neutral distractors on target identification when perceptual or phonological processing of stimuli was required, showing that emotional processing is not as automatic as previously hypothesized. Only when semantic processing of stimuli was required did emotional distractors capture more attention than neutral distractors and increase attentional blink magnitude. Combining the results from 5 experiments, the authors conclude that semantic processing can modulate the attentional capture effect of emotional stimuli. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

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. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The beneficial effects of additional task load, positive affect, and instruction on the attentional blink.

The attentional blink reflects the impaired ability to identify the 2nd of 2 targets presented in close succession--a phenomenon that is generally thought to reflect a fundamental cognitive limitation. However, the fundamental nature of this impairment has recently been called into question by the counterintuitive finding that task-irrelevant mental activity improves attentional blink performance (C. N. L. Olivers & S. Nieuwenhuis, 2005). The present study found a reduced attentional blink when participants concurrently performed an additional memory task, viewed pictures of positive affective content, or were instructed to focus less on the task. These findings support the hypothesis that the attentional blink is due to an overinvestment of attentional resources in stimulus processing, a suboptimal processing mode that can be counteracted by manipulations promoting divided attention. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Modulation of the attentional blink by differential resource allocation.

When one masked target (T2) follows another (T1) in close temporal proximity, identification accuracy of the second target is reduced for a period referred to as the attentional blink. Analysis of the attentional blink literature suggests that increasing the difficulty of T1 processing increases the magnitude of the blink. In a previous study that eliminated several untoward features of the typical attentional blink design (e.g., task switching, location switching, and stream contribution), we found no effect on blink magnitude when three levels of T1 difficulty (manipulated in a data-limited manner) were randomly intermixed. Here, when we repeated the previous study, with 20 college students, using a blocked manipulation of T1 difficulty, which is characteristic of the literature, a significant positive relation between T1 difficulty and blink magnitude was found. Resource allocation put in place to encode T1 in advance of a dual-target trial thus seems to be the critical factor in mediating this relation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Conditioning-induced attentional bias for face stimuli measured with the emotional Stroop task.

People with anxiety disorder display attentional bias toward threat-related objects. Using classical fear conditioning, the authors investigated the possible source of such bias in normal participants. Following differential fear conditioning in which an angry face of either male or female (conditioned stimulus: CS+) was paired with mild electric fingershock (unconditioned stimulus: US) but the angry face of the other gender and all other facial expressions unpaired (CS-), an emotional Stroop task was administered. In the Stroop task, participants were required to identify the color of the facial stimuli (red, green, blue, or yellow). Response latency was significantly longer for the CS+ angry face than the other unpaired facial stimuli (CS-). Furthermore, this acquired attentional bias was positively correlated with the level of trait-anxiety measured before the conditioning and the degree of self-reported aversiveness of the US. Our results demonstrated that attentional bias could be induced in normal individuals through a simple associative learning procedure, and the acquisition is modulated by the level of trait anxiety and the level of perceived fear of the aversive US. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

When do additional distractors reduce the attentional blink?

When 2 targets are embedded in a rapid serial visual presentation stream of distractors, perception of the second target is impaired when the intertarget lag is relatively short (less than 500 ms). Stimuli concurrently presented with the stream can affect this phenomenon, which is called attentional blink (AB). Previous studies have yielded conflicting results concerning the direction of the effect of added distractors on the AB: Some studies report an increased AB, whereas others report a decreased AB. The present study explored the boundary conditions of the exaggeration–reduction effects of distractors on the AB and investigated underlying mechanisms by manipulating the spatial configuration, timing, and type of distractors. The results indicate that the magnitude of the AB deficit increased, regardless of the type of distractors, when spatial uncertainty of the target locations was involved. The reduction of the AB occurred at optimal presentation of distractors and disappeared when the second target was presented at a suprathreshold level. These results suggest that stochastic resonance or the center-surround attentional mechanism may contribute to the reduction effect of distractors on the AB deficit. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Visual masking during the attentional blink: Tests of the object substitution hypothesis.

When 2 masked targets are presented in a rapid sequence, correct identification of the 1st hinders identification of the 2nd. Visual masking of the 2nd target plays a critical role during this 2nd-target deficit, or "attentional blink" (AB). The object substitution hypothesis (B. Giesbrecht and V. Di Lollo, 1998) predicts that late-stage visual processes involved in object substitution mediate masking of the 2nd target during AB, whereby stronger masking should produce a more severe deficit. Six experiments are presented, together testing this hypothesis. Although masking by object substitution was observed, it did not interact with the AB. An alternative hypothesis is proposed stating that mostly early-stage visual processes mediate the masking effects that are critical to the AB. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The fearful-face advantage is modulated by task demands: Evidence from the attentional blink.

Fearful faces receive privileged access to awareness relative to happy and nonemotional faces. We investigated whether this advantage depends on currently available attentional resources. In an attentional blink paradigm, observers detected faces presented during the attentional blink period that could depict either a fearful or a happy expression. Perceptual load of the blink-inducing target was manipulated by increasing flanker interference. For the low-load condition, fearful faces were detected more often than happy faces, replicating previous reports. More important, this advantage for fearful faces disappeared for the high-load condition, during which fearful and happy faces were detected equally often. These results suggest that the privileged access of fearful faces to awareness does not occur mandatorily, but instead depends on attentional resources. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

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

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. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

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 fast 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. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Double take: Parallel processing by the cerebral hemispheres reduces attentional blink.

Recent data have shown that parallel processing by the cerebral hemispheres can expand the capacity of visual working memory for spatial locations (J. F. Delvenne, 2005) and attentional tracking (G. A. Alvarez & P. Cavanagh, 2005). Evidence that parallel processing by the cerebral hemispheres can improve item identification has remained elusive. The authors used a novel variant of the attentional blink paradigm to show that the attentional blink is reduced if targets are divided between the hemispheres rather than directed to a single hemisphere. Parallel processing by the cerebral hemispheres can thus expand the capacity of processes involved in item identification. The authors also show that prior engagement of the attentional system may compromise the processing of items directed to the right visual field. This pseudoextinction may explain the failures of previous attempts to demonstrate that parallel processing can improve item identification (J. F. Delvenne, 2005; S. J. Luck, S. A. Hillyard, G. R. Mangun, & M. S. Gazzaniga, 1989). (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Attentional requirements in visual detection and identification: Evidence from the attentional blink.

Perception of the 2nd of 2 targets (T1 and T2) is impaired if the lag between them is short (0–500 ms). The authors used this attentional blink (AB) to index attentional requirements in detection and identification tasks, with or without backward masking of T2, in 2 stimulus domains (line orientation, coherent motion). With masking, the AB occurred because T2 was masked during the attentional dwell time created by T1 processing (Experiments 1, 2, and 3). Without masking, an AB occurred only in identification because during the attentional dwell time. T2 decayed to a level that could support simple detection but not complex identification. However, an AB occurred also in detection if T2 was sufficiently degraded (Experiment 4). The authors drew 2 major conclusions: (a) Attention is required in both identification and detection, and (b) 2 factors contribute to the AB, masking of T2 while attention is focused on T1 and decay of the T2 trace while unattended. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The attentional blink provides episodic distinctiveness: Sparing at a cost.

The attentional blink (J. E. Raymond, K. L. Shapiro, & K. M. Arnell, 1992) refers to an apparent gap in perception observed when a second target follows a first within several hundred milliseconds. Theoretical and computational work have provided explanations for early sets of blink data, but more recent data have challenged these accounts by showing that the blink is attenuated when subjects encode strings of stimuli (J. Kawahara, T. Kumada, & V. Di Lollo, 2006; M. R. Nieuwenstein & M. C. Potter, 2006; C. N. Olivers, 2007) or are distracted (C. N. Olivers & S. Nieuwenhuis, 2005) while viewing the rapid serial visual presentation stream. The authors describe the episodic simultaneous type, serial token model, a computational account of encoding visual stimuli into working memory that suggests that the attentional blink is a cognitive strategy rather than a resource limitation. This model is composed of neurobiologically plausible elements and simulates the attentional blink with a competitive attentional mechanism that facilitates the formation of episodically distinct representations within working memory. In addition to addressing the blink, the model addresses the phenomena of repetition blindness and whole report superiority, producing predictions that are supported by experimental work. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The sparing is far from spurious: Reevaluating within-trial contingency effects in the attentional blink.

The attentional blink is the marked deficit in awareness of a 2nd target (T2) when it is presented shortly after the 1st target (T1) in a stream of distractors. When the distractors between T1 and T2 are replaced by even more targets, the attentional blink is reduced or absent, indicating that the attentional blink results from online selection mechanisms that act in response to distracting input rather than being the result of T1-induced cognitive resource depletion. However, Dell'Acqua, Jolicoeur, Luria, and Pluchino (2009) recently contended that an attentional blink is found in the multiple-target case as long as the appropriate trial context and analyses are used, thus reinstating resource-based explanations of the attentional blink and challenging the selection account. Specifically, an attentional blink reemerges when target performance is analyzed contingent on previous target accuracy. We argue on theoretical and empirical grounds that neither the trial context nor the type of analysis poses a serious problem for selection accounts. We show that the attentional blink and previous target contingency effects can be dissociated, with the latter depending more on low-level, short-range competition. We conclude that selection mechanisms involved in filtering for targets still provide a strong and coherent explanation of the attentional blink. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Children induce an enhanced attentional blink in child molesters.

The attentional blink (AB) is a robust phenomenon that has been consistently reported in the cognitive literature. The AB is found when two target images (T1, T2) are presented within 500 ms of each other and errors are induced on the perceptual report of T2. The AB may increase when T1 has some salience to the viewer. This study examined the effects of using pictures of children as T1 on the AB in a sample of child molesters. A larger AB emerged in this sample when T1was a picture of a child compared with when T1 was a picture of an animal. It is argued that this task may be potentially useful to assess child molesters' level of interest in children. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Top-down controlled, delayed selection in the attentional blink.

In a previous study, it was shown that the attentional blink (AB)--the failure to recall the 2nd of 2 visual targets (T1 and T2) presented within 500 ms in rapid serial visual presentation--is reduced when T2 is preceded by a distractor that shares a feature with T2 (e.g., color; Nieuwenstein, Chun, van der Lubbe & Hooge, 2005). Here, this cuing effect is shown to be contingent on attentional set. For example, a red distractor letter preceding a green digit T2 is an effective cue when the task is to look for red and green digits, but the same red cue is relatively ineffective when the task is to look for only green digits or when the color of T2 is not specified. It is also shown that cuing is not interrupted by a distractor intervening between the cue and T2. These findings provide evidence for a contingent, delayed selection account of the AB. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

The emotional blink: Adult age differences in visual attention to emotional information.

To assess age differences in attention-emotion interactions, the authors asked young adults (ages 18-33 years) and older adults (ages 60-80 years) to identify target words in a rapid serial visual presentation (RSVP) task. The second of two target words was neutral or emotional in content (positive in Experiment 1, negative in Experiment 2). In general, the ability to identify targets from a word stream declined with age. Age differences specific to the attentional blink were greatly reduced when baseline detection accuracy was equated between groups. With regard to emotion effects, older adults showed enhanced identification of both positive and negative words relative to neutral words, whereas young adults showed enhanced identification of positive words and reduced identification of negative words. Together these findings suggest that the nature of attention-emotion interactions changes with age, but there was little support for a motivational shift consistent with emotional regulation goals at an early stage of cognitive processing. (PsycINFO Database Record (c) 2010 APA, all rights reserved)