Both exogenous and endogenous target salience manipulations support resource depletion accounts of the attentional blink: A reply to Olivers, Spalek, Kawahara, and Di Lollo (2009)

Input control theories of the attentional blink (AB) suggest that this deficit results from impaired attentional selection caused by the post-Target 1 (T1) distractor (Di Lollo, Kawahara, Ghorashi, & Enns, 2005; Olivers, van der Stigchel, & Hulleman, 2007). Accordingly, these theories predict that there should be no AB when no distractors intervene between the targets. Contrary to these hypotheses, Dux, Asplund, and Marois (2008) observed an AB (T3 deficit) when three targets, from the same attentional set, were presented successively in a rapid stream of distractors, if subjects increased the resources they devoted to T1 processing. This result is consistent with resource depletion accounts of the AB. However, Olivers, Spalek, Kawahara, and Di Lollo (2009) argue that Dux et al.’s results can be better explained by the relationship between T1 and T2, and by target discriminability effects, rather than by the relationship between T1 and T3. Here, we find that manipulating the resources subjects devote to T1, either exogenously (target perceptual salience) or endogenously (target task relevance), affects T3 performance, even when T2 and target discriminability differences are controlled for. These results support Dux et al.’s conclusion that T1 resource depletion underlies the AB.     

The attentional blink: Resource depletion or temporary loss of control?

Identification of the second of two targets is impaired if it is presented less than about 500 ms after the first. Theoretical accounts of this second-target deficit, known as attentional blink (AB), have relied on some form of limited attentional resource that is allocated to the leading target at the expense of the trailing target. Three experiments in the present study reveal a failure of resource-limitation accounts to explain why the AB is absent when the targets consist of a stream of three items belonging to the same category (e.g., letters or digits). The AB is reinstated, however, if an item from a different category is inserted in the target string. This result, and all major results in the AB literature, is explained by the hypothesis that the AB arises from a temporary loss of control over the prevailing attentional set. This lapse in control renders the observer vulnerable to an exogenously-triggered switch in attentional set.     

Alerting enhances target identification but does not affect the magnitude of the attentional blink

Identification of the second of two targets is impaired when presented less than about 500 ms after the first. The magnitude of this attentional blink (AB) is known to be modulated by tonic factors (e.g., observer's state of relaxation). The present work examined the effects of a phasic change in observer's state brought about by an alerting stimulus (an aggregate of faint rings) presented in temporal proximity to either letter-target inserted in a temporal stream (RSVP) of digit distractors. In four experiments, identification accuracy of each target was substantially improved by presenting the alerting stimulus either in the target's frame or in the preceding RSVP frame. However, alerting did not modulate the magnitude of the AB. The appearance of an alerting effect on the AB in Experiment 1 was ascribed to a ceiling effect in Experiment 2. Experiment 3 ruled out endogenous temporal cueing effects; Experiment 4 examined the temporal gradient of alerting. Independence of the alerting and AB effects suggests that the alerting stimuli and the letter targets may be processed along distinct visual pathways.     

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.     

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

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

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

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

Sparing and impairing: Emotion modulation of the attentional blink and the spread of sparing in a 3-target RSVP task

The performance impairment (attentional blink, AB) on a second target (T2) when it is presented within 200-500 ms after a first target (T1) during rapid serial visual presentation (RSVP) is typically attributed to resource depletion. The AB does not occur when targets appear in immediate sequence (sparing). Recently, this account has been challenged by findings that the lag 1 sparing can spread to later lags when using a 3-target RSVP. Two experiments using the 3-targets RSVP investigated the relative contribution of resource depletion and attentional enhancement and/or inhibition on the AB and the sparing when T1 (Exp. 1) or T3 (Exp. 2) are emotionally salient. Findings showed a greater sparing for neutral T3s when preceded by negative compared with neutral T1s (Exp. 1) and for negative T3s (Exp. 2). In contrast, the AB on neutral T3s was greater after negative than after neutral T1s (Exp. 1), but it was reduced when T3 was negative (Exp. 2). The AB and the sparing also depended on how many targets before T3 were correctly reported. These findings indicate that although there is a cost for processing multiple targets, the emotional modulations of the AB and the sparing are better explained by an interplay between emotion-enhancement and capacity limitations on temporal selective attention.     

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.     

Representational masking and the attentional blink

After successful detection of a target item within a stream of rapidly displayed visual stimuli, subsequent detection of an additional target is impaired for roughly 500 ms. This impairment is known as the “attentional blink” (AB). Previous studies have found that if either the first (Tl; Raymond, Shapiro, & Arnell, 1992) or second target (T2; Giesbrecht & Di Lollo, 1998) is not followed by a mask, the AB impairment is significantly reduced. Whereas low-level perceptual factors have been found to influence the efficacy of masking in the AB (e.g., Seiffert & Di Lollo, 1997), the current experiment used a higher level (representational) manipulation, i.e., repetition blindness to reduce the efficacy of target masking in the AB. These findings contribute to the growing literature suggesting that masking plays more than a perceptual role in the AB phenomenon.     

Capturing and holding attention: The impact of emotional words in rapid serial visual presentation

When two masked, to-be-attended targets are presented within approximately 500 msec of each other, accurate report of the second target (T2) suffers more than when targets are presented farther apart in time--an attentional blink (AB). In the present study, the AB was found to be larger when taboo words were presented as a first target (T1), as compared with the AB found when emotionally neutral, negative, or positive words were presented as T1, suggesting that taboo words received preferential attentional processing. Comparable results were also obtained when taboo words were presented as to-be-ignored distractors in single-target rapid serial visual presentation (RSVP). Arousal, but not valence, ratings of the emotional words predicted accuracy on subsequent targets in both dual- and single-task RSVP. Recognition memory for taboo words accounted fully for the negative relationships between arousal ratings and accuracy on subsequent targets, suggesting that arousal-triggered changes in attentional allocation influenced encoding of taboo words at the time they were encountered.     

Cross-task repetition amnesia: Impaired recall of RSVP targets held in memory for a secondary task

People often fail to select and encode the second of two targets presented within less than 500ms in rapid serial visual presentation (RSVP), an effect known as the attentional blink. We investigated how report of the two targets is affected when one of them is maintained in working memory for a secondary, memory-search task. The results showed that report of either target was impaired when it was a member of the memory set relative to when it was not. This effect was independent of both the temporal interval separating the RSVP target from the presentation of the memory set and the interval separating the targets. We propose that the deficit in recall occurs because the association between a target and the memory-search task interferes with the formation of a new association between that target and the following RSVP task, with the result that observers may be biased to ascribe the target only to the memory set.     

The “beam of darkness”: Spreading of the attentional blink within and between objects

When two targets (T1 and T2) are inserted into a rapid serial visual presentation (RSVP) stream of nontargets, observers are impaired at identifying T2 when it is presented within half a second after T1. This transient drop in performance, or attentional blink (AB), has been attributed to a temporary unavailability of task-critical processing resources. In the present study, we investigated how object-based attention modulates the AB, by presenting four synchronized RSVP streams in the corners of two rectangular bars (e.g., one above and one below fixation). The results from four experiments revealed that the AB increased within short temporal lags (of up to ～400 msec) when T2 was presented on the same, rather than a different, bar as T1 (with T1–T2 spatial distance controlled for). Thus, the AB is seen to spread across entire object groupings, suggesting that the spatiotemporal resolution of attention is modulated by global-object information.     

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.     

Sparing from the attentional blink is not spared from structural limitations

When a series of three successive to-be-reported items (targets) is displayed in a rapid serial visual presentation (RSVP) stream of distractors, it has been shown that no attentional blink—a marked impairment in the report of the second of two targets, typically observed when the targets appear within 200–600 ms of one another—occurs in target accuracy. The present study examines three recently introduced computational models that provide different explanations of this protracted sparing effect. Using a standard RSVP design and these models, we provide empirical data and simulations that illustrate that structural limitations affect the processing of successive targets. In addition, we compare the candidate mechanisms that might underlie these limitations.     

The attentional blink is governed by a temporary loss of control

Identification of the second of two brief targets is impaired at intertarget lags of less than about 500 msec. We compared two accounts of thisattentional blink (AB) by manipulating the number of digit distractors—and hence the lag—inserted among three letter targets in a rapid serial visual presentation stream of digit distractors. On the resource-depletion hypothesis, longer lags provide more time for processing the leading target, thus releasing resources for the trailing target. On the temporary-loss-of-control (TLC) hypothesis, intervening distractors disrupt the current attentional set, producing a trailing-target deficit. Identification accuracy for trailing targets was unimpaired not only at lag 1 (conventional lag 1 sparing) but also at later lags, if preceded by another target. The results supported the TLC hypothesis but not the resource-depletion hypothesis. We conclude that the AB is caused by a disruption in attentional set when a distractor is presented while the central executive is busy processing a leading target.     

情绪性注意瞬脱的认知机制:来自行为与ERP的证据

从过度投入理论与激活反弹理论对瓶颈理论的质疑出发,采用ERP技术检验了情绪性注意瞬脱的加工过程及其神经机制。行为结果显示,以恐惧面孔为T1,中性场景图片为T2,则恐惧面孔T1相对中性面孔T1显著降低了中性T2的识别正确率,进而诱发了情绪性注意瞬脱。ERP结果进一步显示,相较于中性面孔T1,恐惧面孔T1诱发的情绪加工影响了代表中枢加工资源的两阶段P3波幅,使得其始终高于代表标准注意瞬脱的中性面孔T1条件和代表非注意瞬脱的单任务基线条件。以上结果证明,情绪性注意瞬脱形成自情绪性T1加工所诱发的中枢资源过度投入,而非源自中枢资源瓶颈。     

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.     

New objects,not new features,trigger the attentional blink

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

Previous attentional set can induce an attentional blink with task-irrelevant initial targets

Identification of a second target is often impaired by the requirement to process a prior target in a rapid serial visual presentation (RSVP). This is termed the attentional blink. Even when the first target is task irrelevant an attentional blink may occur providing this first target shares similar features with the second target (contingent capture). An RSVP experiment was undertaken to assess whether this first target can still cause an attentional blink when it did not require a response and did not share any features with the following target. The results revealed that such task-irrelevant targets can induce an attentional blink providing that they were task relevant on a previous block of trials. This suggests that irrelevant focal stimuli can distract attention on the basis of a previous attentional set.     

RSVP in orbit: Identification of single and dual targets in motion

Three experiments using rapid serial visual presentation (RSVP) tested participants' ability to detect targets in streams that are in motion. These experiments compared the ability to identify moving versus stationary RSVP targets and examined the attentional blink with pairs of targets that were moving or stationary. One condition presented RSVP streams in the center of the screen; a second condition used an RSVP that was orbiting in a circle, with participants instructed to follow the stream with their eyes; and a third condition had participants fixate in the middle while observing a circling RSVP stream. Relative to performance in stationary RSVP streams, participants were not markedly impaired in detecting single targets in RSVP streams that were moving, either with or without instructions to pursue the motion. In streams with two targets, a normal attentional blink effect was observed when participants were instructed to pursue the moving stream. When participants had to maintain central fixation as the RSVP stream moved, the attentional blink was nearly absent even when a trailing mask was added. We suggest that the reduction of the attentional blink for moving RSVP streams may reflect a reduced ability to perceive the temporal boundaries of the individual items.