The role of working memory in auditory selective attention

A growing body of research now demonstrates that working memory plays an important role in controlling the extent to which irrelevant visual distractors are processed during visual selective attention tasks (e.g., Lavie, Hirst, De Fockert, & Viding, 2004). Recently, it has been shown that the successful selection of tactile information also depends on the availability of working memory (Dalton, Lavie, & Spence, 2009). Here, we investigate whether working memory plays a role in auditory selective attention. Participants focused their attention on short continuous bursts of white noise (targets) while attempting to ignore pulsed bursts of noise (distractors). Distractor interference in this auditory task, as measured in terms of the difference in performance between congruent and incongruent distractor trials, increased significantly under high (vs. low) load in a concurrent working-memory task. These results provide the first evidence demonstrating a causal role for working memory in reducing interference by irrelevant auditory distractors.     

Concurrent working memory load can facilitate selective attention: evidence for specialized load

Load theory predicts that concurrent working memory load impairs selective attention and increases distractor interference (N. Lavie, A. Hirst, J. W. de Fockert, & E. Viding). Here, the authors present new evidence that the type of concurrent working memory load determines whether load impairs selective attention or not. Working memory load was paired with a same/different matching task that required focusing on targets while ignoring distractors. When working memory items shared the same limited-capacity processing mechanisms with targets in the matching task, distractor interference increased. However, when working memory items shared processing with distractors in the matching task, distractor interference decreased, facilitating target selection. A specialized load account is proposed to describe the dissociable effects of working memory load on selective processing depending on whether the load overlaps with targets or with distractors.     

The role of working memory in tactile selective attention

Load theory suggests that working memory controls the extent to which irrelevant distractors are processed (e.g., Lavie, Hirst, De Fockert, & Viding, 2004). However, so far this proposal has only been tested in vision. Here, we examine the extent to which tactile selective attention also depends on working memory. In Experiment 1, participants focused their attention on continuous target vibrations while attempting to ignore pulsed distractor vibrations. In Experiment 2, targets were always presented to a particular hand, with distractors being presented to the other hand. In both experiments, a high (vs. low) load in a concurrent working memory task led to greater interference by the tactile distractors. These results establish the role of working memory in the control of tactile selective attention, demonstrating for the first time that the principles of load theory also apply to the tactile modality.     

Controlling for dilution while manipulating load: Perceptual and sensory limitations are just two aspects of task difficulty

Lavie and de Fockert (2003) proposed that perceptual load and sensory limitations reflect two distinct mechanisms producing opposite effects: Perceptual load eliminates distractor interference, whereas sensory limitations enhance it. Tsal and Benoni (2010a) suggested that these results may have been due to the confounding effect of dilution--that is, to the presence (perceptual load) or absence (sensory load) of neutral items capable of diluting distractor interference. In the present study, we jointly manipulated dilution with perceptual load and with sensory degradation. The results show that, with both perceptual and sensory manipulations, the presence of diluting items eliminates distractor interference, whereas controlling for dilution increases distractor interference. We therefore conclude that perceptual and sensory limitations are just two aspects of task difficulty.     

工作记忆内容驱动完全无关刺激捕获注意

研究通过三个实验以检验工作记忆内容能否自动引导注意选择视场中与之匹配的任务完全无关刺激。实验一要求被试在工作记忆保持阶段完成一个视觉搜索任务，结果发现当搜索序列外的无关干扰刺激与工作记忆内容匹配时搜索绩效显著降低；实验二结果表明该干扰效应不能归因于自下而上的启动机制，因为对颜色刺激仅仅进行知觉辨认而没有工作记忆加工时并没有产生启动效应；实验三通过缩短搜索任务刺激的呈现时间以使得被试在完成搜索任务前没有足够时间眼跳至无关干扰刺激，结果发现了与实验一类似的干扰效应，说明在没有眼跳的情况下与工作记忆内容匹配的完全无关刺激可以捕获注意。这些结果表明保持在工作记忆中的信息表征可以自动引导注意选择视场中与之匹配的任务完全无关刺激，为基于工作记忆内容的注意捕获提供了新证据支持。     

工作记忆表征引导视觉注意选择的眼动研究

工作记忆表征能否引导视觉注意选择？目前实验结果尚不一致。有研究者认为能否观察到注意引导效应取决于视觉搜索类型。研究采用工作记忆任务与视觉搜索任务相结合的双任务范式, 结合眼动追踪技术, 对不同视觉搜索类型下的注意引导效应进行验证。实验1结果发现, 不管视觉搜索任务的靶子是否变化, 在早期的眼动指标上都发现了显著的注意引导效应, 但注意引导效应在靶子固定的视觉搜索任务下表现得更强。实验2在平衡两种视觉搜索任务中的工作记忆负载后发现, 两种视觉搜索任务下都出现了显著的注意引导效应, 但没有发现实验1中所出现的任务间差异。实验结果否定了视觉搜索类型对注意引导效应的决定性影响, 同时也提示工作记忆负载可能在注意引导效应中起重要作用。     

工作记忆表征捕获眼动中的颜色优先性

刺激属性所具有的引导效力在工作记忆表征自上而下地引导注意捕获过程中起重要作用, 已有研究表明工作记忆表征的颜色属性在引导注意时具有一定的优势。研究采用工作记忆任务与视觉搜索任务相结合的双任务范式, 结合眼动追踪技术, 通过设置具有较强引导效力的颜色属性与朝向属性进行直接竞争的实验条件, 进一步考察工作记忆表征的颜色属性是否依然具有优先性。实验1发现工作记忆表征的颜色属性与朝向属性同时竞争眼动捕获时, 颜色属性表现出较强的优势, 而朝向属性单独呈现时并未表现出任何捕获效应。实验2与3进一步证实了颜色属性捕获眼动的优先性, 即当颜色属性在面临作为靶子属性的朝向属性的竞争时, 依然能捕获更多的注视点。这些结果直接证实了工作记忆表征的颜色属性在工作记忆表征的捕获眼动的过程中具有较强的引导效力, 相对于其他刺激属性(如朝向、形状)更具有优先性。     

P50 sensory gating is related to performance on select tasks of cognitive inhibition

P50 suppression deficits have been documented in clinical and nonclinical populations, but the behavioral correlates of impaired auditory sensory gating remain poorly understood. In the present study, we examined the relationship between P50 gating and healthy adults’ performance on cognitive inhibition tasks. On the basis of load theory (Lavie, Hirst, de Fockert, & Viding, 2004), we predicted that a high perceptual load, a possible consequence of poor auditory P50 sensory gating, would have differential (i.e., positive vs. negative) effects on performance of cognitive inhibition tasks. A dissociation was observed such that P50 gating was negatively related to interference resolution on a Stroop task and positively related to response inhibition on a go/no-go task. Our findings support the idea that a high perceptual load may be beneficial to Stroop performance because of the reduced processing of distractors but detrimental to performance on the go/no-go task because of interference with stimulus discrimination.     

工作记忆表征的激活与抑制状态对注意引导效应的影响

本研究采用双任务范式, 通过定向遗忘任务操纵工作记忆表征状态, 分别在目标无关和目标相关条件下考察工作记忆激活与抑制状态对视觉搜索早期注意引导效应的影响。实验1与实验2发现当工作记忆表征只可能与视觉搜索分心物匹配时(目标无关条件), 处于激活状态的工作记忆表征会引导视觉注意偏向到与之匹配的分心物, 表现出注意引导效应, 而处于抑制状态的工作记忆表征则没有观察到注意引导效应。实验3与实验4发现, 当工作记忆表征有可能与视觉搜索目标匹配时(目标相关条件), 处于激活状态的工作记忆表征能捕获注意, 而处于抑制状态的工作记忆表征只有与视觉搜索目标匹配时, 才表现出对该搜索目标反应的延迟。这些研究的结果表明(1)处于激活状态的工作记忆表征能有效地引导注意偏向到与之匹配的搜索目标或分心物, 并且这种注意引导效应并未受到抑制动机的影响而被消除或反转; (2)处于抑制状态的工作记忆表征能将抑制状态传递到视觉搜索阶段, 并延迟对与之匹配的搜索目标的反应。     

Interactions Between Modality of Working Memory Load and Perceptual Load in Distractor Processing

The present study investigated interactions between working memory load and perceptual load. The load theory (Lavie, Hirst, de Fockert, &; Viding, 2004 Lavie, N., Hirst, A., de Fockert, J.W., &; Viding, E. (2004). Load theory of selective attention and cognitive control. Journal of Experimental Psychology: General, 133, 339–354.[Crossref], [PubMed], [Web of Science ®] , [Google Scholar]) claims that perceptual load decreases distractor interference, whereas working memory load increases interference. However, recent studies showed that effects of working memory might depend on the relationship between modalities of working memory and task stimuli. Here, we examined whether the relationship between working memory load and perceptual load would remain the same across modalities. The results of Experiment 1 showed that verbal working memory load did not affect a compatibility effect for low perceptual load, whereas it increased the compatibility effect for high perceptual load. In Experiment 2, the compatibility effect remained the same regardless of visual working memory load. These results suggest that the effects of working memory load and perceptual load depend on the relationship between the modalities of working memory and stimuli.     

Asymmetrical perceptual load in lateralised word processing

We applied the Load Theory of attention (Lavie, 1995, 2005) to the case of distraction during processing of lateralised words presented in either the right or the left visual fields. Previous research (Brand-D'Abrescia & Lavie, 2007) showed that lexicality affects selective attention such that the number of letters in a search task only increases perceptual load and reduces irrelevant distractor effects for searches in nonwords but not in words. The present study examined the hypothesis that the effect of lexicality on distractor processing would be stronger for words presented to the left compared to the right hemisphere. The results supported this hypothesis and their implications for attention to words in the two cerebral hemispheres are discussed. We suggest that the efficiency of attentional selection differed because perceptual load in the visual fields taxed processing depending on hemispheric language expertise.     

Strategic and automatic effects of visual working memory on attention in visual search

Previous research indicates that visual attention can be automatically captured by sensory inputs that match the contents of visual working memory. However, Woodman and Luck (2007) showed that information in working memory can be used flexibly as a template for either selection or rejection according to task demands. We report two experiments that extend their work. Participants performed a visual search task while maintaining items in visual working memory. Memory items were presented for either a short or long exposure duration immediately prior to the search task. Memory was tested by a change-detection task immediately afterwards. On a random half of trials items in memory matched either one distractor in the search task (Experiment 1) or three (Experiment 2). The main result was that matching distractors speeded or slowed target detection depending on whether memory items were presented for a long or short duration. These effects were more in evidence with three matching distractors than one. We conclude that the influence of visual working memory on visual search is indeed flexible but is not solely a function of task demands. Our results suggest that attentional capture by perceptual inputs matching information in visual working memory involves a fast automatic process that can be overridden by a slower top-down process of attentional avoidance.     

Dilution, not load, affects distractor processing

Lavie and Tsal (1994) proposed that spare attentional capacity is allocated involuntarily to the processing of irrelevant stimuli, thereby enabling interference. Under this view, when task demands increase, spare capacity should decrease and distractor interference should decrease. In support, Lavie and Cox (1997) found that increasing perceptual load by increasing search set size decreased interference from an irrelevant distractor. In three experiments, we manipulated the cue set size (number of cued locations) independently of the display set size (number of letters presented). Increasing the display set size reduced distractor interference regardless of whether the additional letters were relevant to the task. In contrast, increasing the cue set size increased distractor interference. Both findings are inconsistent with the load explanation, but are consistent with a proposed two-stage dilution account.     

Attentional capture in serial audiovisual search tasks

The phenomenon of attentional capture has typically been studied in spatial search tasks. Dalton and Lavie recently demonstrated that auditory attention can also be captured by a singleton item in a rapidly presented tone sequence. In the experiments reported here, we investigated whether these findings extend cross-modally to sequential search tasks using audiovisual stimuli. Participants searched a stream of centrally presented audiovisual stimuli for targets defined on a particular dimension (e.g., duration) in a particular modality. Task performance was compared in the presence versus absence of a unique singleton distractor. Irrelevant auditory singletons captured attention during visual search tasks, leading to interference when they coincided with distractors but to facilitation when they coincided with targets. These results demonstrate attentional capture by auditory singletons during nonspatial visual search.     

Practice in visual search produces decreased capacity demands but increased distraction

Lavie (1995) proposed a load account of selective attention, which holds that spare capacity is involuntarily allocated to the processing of irrelevant stimuli. In support of this account, Lavie and Cox (1997) combined a letter search task with a flanker task and found that increasing load (search set size) resulted in decreased interference from an irrelevant distractor letter. In three experiments using a very similar procedure, we varied distractor location and distractor distinctiveness and observed that as load increased (from set size 2 to set size 6), there was a consistent reduction in interference. Critically, we addressed a fundamental hypothesis derived from the load account-that practice reduces capacity demands. This hypothesis leads to the rather counterintuitive prediction that as performance improves with practice, distractor processing should actually increase. Indeed, we found that interference in a high-load condition (set size 6), but not in a low-load condition (set size 2), did increase with practice. We describe a two-stage dilution account of attention that accommodates these results.     

Working memory load and distraction: dissociable effects of visual maintenance and cognitive control

We establish a new dissociation between the roles of working memory (WM) cognitive control and visual maintenance in selective attention as measured by the efficiency of distractor rejection. The extent to which focused selective attention can prevent distraction has been shown to critically depend on the level and type of load involved in the task. High perceptual load that consumes perceptual capacity leads to reduced distractor processing, whereas high WM load that reduces WM ability to exert priority-based executive cognitive control over the task results in increased distractor processing (e.g., Lavie, Trends in Cognitive Sciences, 9(2), 75–82, 2005). WM also serves to maintain task-relevant visual representations, and such visual maintenance is known to recruit the same sensory cortices as those involved in perception (e.g., Pasternak & Greenlee, Nature Reviews Neuroscience, 6(2), 97–107, 2005). These findings led us to hypothesize that loading WM with visual maintenance would reduce visual capacity involved in perception, thus resulting in reduced distractor processing—similar to perceptual load and opposite to WM cognitive control load. Distractor processing was assessed in a response competition task, presented during the memory interval (or during encoding; Experiment 1a) of a WM task. Loading visual maintenance or encoding by increased set size for a memory sample of shapes, colors, and locations led to reduced distractor response competition effects. In contrast, loading WM cognitive control with verbal rehearsal of a random letter set led to increased distractor effects. These findings confirm load theory predictions and provide a novel functional distinction between the roles of WM maintenance and cognitive control in selective attention.     

基于记忆的注意捕获和注意抑制效应：ERP证据

采用工作记忆与视觉搜索双任务范式, 通过操作匹配试次出现概率来诱发不同水平的认知控制动机, 考察了基于记忆的注意引导过程的时程特点。结果：记忆匹配刺激首先诱发了N2pc成分, 随后诱发了与抑制过程相关的差异正波。并且, 认知控制动机水平越高, N2pc波幅越小、潜伏期越短; 抑制性差异正波波幅越大。结论：基于记忆的注意引导过程包括早期的注意捕获和后期的注意抑制两个阶段; 其效应量和时程受到认知控制动机水平的调节。     

Were you paying attention to where you looked? The role of executive working memory in visual search

Recent evidence has indicated that performing a working memory task that loads executive working memory leads to less efficient visual search (Han & Kim, 2004). We explored the role that executive functioning plays in visual search by examining the pattern of eye movements while participants performed a search task with or without a secondary executive working memory task. Results indicate that executive functioning plays two roles in visual search: the identification of objects and the control of the disengagement of attention.     

Interference from familiar natural distractors is not eliminated by high perceptual load

A crucial prediction of perceptual load theory is that high perceptual load can eliminate interference from distractors. However, Lavie et al. (Psychol Sci 14:510–515, 2003) found that high perceptual load did not eliminate interference when the distractor was a face. The current experiments examined the interaction between familiarity and perceptual load in modulating interference in a name search task. The data reveal that high perceptual load eliminated the interference effect for unfamiliar distractors that were faces or objects, but did not eliminate the interference for familiar distractors that were faces or objects. Based on these results, we proposed that the processing of familiar and natural stimuli may be immune to the effect of perceptual load.     

无关工作记忆表征的负性情绪信息能否捕获视觉注意?一项眼动研究

研究通过分析视觉搜索任务的首次注视点和行为反应时, 探讨无关工作记忆表征的负性情绪信息对视觉注意选择的影响。实验1发现在反映早期注意选择的首次注视点百分率指标上, 不管工作记忆表征的情绪效价如何, 均出现了显著的注意捕获效应; 实验2发现当采用中性情绪靶子刺激时, 首次注视点百分率指标上仍表现出了稳健的注意捕获效应; 在首次注视点持续时间指标上, 实验1和实验2均发现记忆匹配条件的干扰刺激显著小于控制条件的干扰刺激, 表现出注意的快速脱离; 而在行为反应时指标上, 早期的注意捕获效应消失(实验1), 甚至被反转为注意抑制效应(实验2)。这些结果表明在早期注意选择阶段, 记忆驱动的注意捕获效应不受工作记忆表征情绪效价的影响, 但认知控制会在早期注意捕获之后促使注意快速脱离记忆匹配的干扰刺激, 其作用效果受靶子刺激情绪效价的调节。