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。     

认知控制在工作记忆表征引导注意中的作用:来自眼动的证据

研究同时采用首次注视点百分率与行为反应时指标,探讨了认知控制在无关工作记忆表征引导视觉注意选择过程中的作用。实验1发现:当视觉搜索容易时,首次注视点百分率和反应时指标都出现了注意引导效应;而当视觉搜索困难时,在反映早期注意定向的首次注视点百分率指标上,搜索快的被试组的注意引导效应显著大于搜索慢的被试组,而在行为反应时指标上,搜索快的被试组表现出注意引导效应,但搜索慢的被试组则表现出相反的注意拒绝效应。实验2发现当采用更为突显的靶子刺激时,首次注视点百分率指标上表现出的注意引导效应并未受到视觉搜索靶子显著性的影响,甚至还表现出一定的优先性。这些结果表明认知控制在工作记忆表征引导视觉注意的过程中所起的作用是动态变化的,视觉搜索早期注意定向阶段的注意引导效应比较稳健,认知控制只能减弱其效应的量值,而在随后的视觉搜索过程中,当视觉搜索比较缓慢时,认知控制可能会将注意引导效应反转为相反的注意拒绝效应。     

工作记忆表征对视觉注意的影响:基于非目标模板的视角

储存在工作记忆中的视觉表征会影响注意选择过程。其中,与目标有关的工作记忆表征(靶子模板)对视觉注意起到自上而下的引导作用,而与目标无关的工作记忆表征(非目标模板)亦会对注意分配产生影响。本文通过系统分析非目标工作记忆表征影响视觉搜索过程的相关研究,发现非目标模板在视觉搜索任务中既存在自动化的注意捕获,也会形成主动抑制以提高目标搜索绩效。进一步地,对非目标模板的注意捕获或抑制受实验范式、任务难度、刺激材料特征以及认知控制水平等因素的影响。未来研究应该在不断深入细化变量操纵、完善变量控制的同时,进一步扩展应用领域的研究。     

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。     

工作记忆内容对空间返回抑制的影响

工作记忆内容能够以相对自动化的方式引导视觉选择性注意。研究的目的在于考察工作记忆内容对空间返回抑制的影响。实验一要求被试在客体工作记忆保持阶段完成返回抑制任务,结果发现无论返回抑制任务目标是否与工作记忆内容匹配都出现了返回抑制效应。实验二要求被试在空间工作记忆保持阶段完成返回抑制任务,结果发现当目标落在记忆空间上时返回抑制效应消失。因此,空间返回抑制仅会受到基于空间工作记忆的视觉注意引导的影响。     

视觉工作记忆负载类型对注意选择的影响

通过操纵Flanker任务相对于视觉工作记忆任务的呈现位置, 探讨在视觉工作记忆编码和保持阶段, 精度负载和容量负载对注意选择的影响。行为结果发现, Flanker任务呈现位置和视觉工作记忆负载类型影响注意选择; ERP结果发现, 在保持阶段, 当搜索目标和干扰项不一致时, 负载类型影响N2成分。研究表明, 在编码阶段, 视觉工作记忆负载主要通过占用更多知觉资源降低干扰效应, 支持知觉负载理论; 而在保持阶段, 当Flanker任务位于记忆项内部时, 两类负载在工作记忆表征过程中不同的神经活动导致投入到注意选择的认知控制资源不同, 可能是两类负载影响保持阶段注意选择的机制。     

工作记忆与知觉负载对工作记忆表征引导注意的调节

本研究采用4个眼动实验探讨不同知觉负载条件下的视觉搜索任务中工作记忆负载对基于工作记忆表征的注意引导效应的影响。实验1和实验3采用低知觉负载的视觉搜索任务,结果在视觉工作记忆负载为1和2时观察到了显著的注意引导效应,但当负载增加到4时注意引导效应消失了;实验2和实验4采用高知觉负载的视觉搜索任务,结果发现注意引导效应在工作记忆负载增加到2时就已经消失了。上述结果表明:工作记忆负载和知觉负载都能够通过调控认知资源的方式来影响工作记忆表征对注意的引导,当认知资源充足时,工作记忆能够同时保持多个记忆表征对视觉注意的引导。     

颜色凸显条件下基于工作记忆内容的视觉注意

采用记忆任务与视觉搜索任务相结合的实验范式,通过操纵背景颜色与刺激颜色,考察了工作记忆内容对视觉注意的引导是否存在强自动性。实验一通过操作背景颜色以突显记忆项目,结果发现即使工作记忆内容在匹配分心物的情况下仍然自动地捕获视觉注意。实验二通过操作背景颜色以突显目标项目,结果发现工作记忆内容对视觉注意的自动引导作用消失。说明了与工作记忆内容匹配的刺激能够自动地引导视觉注意,但是这种引导并非完全自动化,具有一定的条件性。     

无关长时记忆表征能否引导视觉注意选择?

与任务相关的长时记忆表征在引导视觉注意选择的过程中扮演着重要的角色,它可以使人们在熟悉的视觉情境中快速搜索目标刺激,并偏离干扰刺激。但当长时记忆表征与任务无关时,还能否引导视觉注意选择?目前还不清楚。实验1采用眼动追踪技术直接比较无关工作记忆表征与无关长时记忆表征在视觉搜索阶段对视觉注意的捕获效应,行为反应时与首次注视点百分率的结果都发现,当无关工作记忆表征在视觉搜索中再次出现时能引导视觉注意偏向到与之匹配的干扰刺激,但无关长时记忆表征并没有表现出类似的注意引导效应;实验2探讨记忆表征由工作记忆系统转移到长时记忆系统的过程中对视觉注意的引导效应,结果发现,随着记忆表征的转移,注意引导效应消失了,实验3排除工作记忆表征的干扰后,依然没有发现无关长时记忆表征对注意的引导效应。以上结果表明,无关长时记忆表征并不能像工作记忆表征一样引导视觉注意选择,工作记忆表征和长时记忆表征对视觉注意的引导属于两个不同的认知过程。     

Memory-based attentional capture by colour and shape contents in visual working memory

Current theories assume that there is substantial overlap between visual working memory (VWM) and visual attention functioning, such that active representations in VWM automatically act as an attentional set, resulting in attentional biases towards objects that match the mnemonic content. Most evidence for this comes from visual search tasks in which a distractor similar to the memory interferes with the detection of a simultaneous target. Here we provide additional evidence using one of the most popular paradigms in the literature for demonstrating an active attentional set: The contingent spatial orienting paradigm of Folk and colleagues. This paradigm allows memory-based attentional biases to be more directly attributed to spatial orienting. Experiment 1 demonstrated a memory-contingent spatial attention effect for colour but not for shape contents of VWM. Experiment 2 tested the hypothesis that the placeholders used for spatial cueing interfered with the shape processing, and showed that memory-based attentional capture for shape returned when placeholders were removed. The results of the present study are consistent with earlier findings from distractor interference paradigms, and provide additional evidence that biases in spatial orienting contribute to memory-based influences on attention.     

视觉搜索中基于工作记忆内容的注意捕获与抑制

注意是对有关信息的选择及对无关信息的抑制, 工作记忆是对有关信息的保持以及对无关信息的抑制, 两者在一定程度上都体现了选择性地指向与当前任务有关的刺激并同时抑制无关刺激。在系统地回顾已有研究的基础上结合新近的ERP研究, 从视觉搜索中基于工作记忆内容的注意捕获与注意抑制两个角度综述了视觉工作记忆与视觉选择性注意的相关研究。研究者们主要从两方面对该领域的问题进行了探讨：(1)视觉工作记忆内容对视觉选择性注意的导向作用; (2)视觉工作记忆内容对视觉选择性注意产生导向作用的条件。文章对以往的研究进行了总结, 指出了无论保持在视觉工作记忆的内容是捕获注意还是受到抑制, 都存在着自上而下和自下而上两种加工机制。     

非目标工作记忆表征下颜色关联和抽象关联的注意捕获和抑制

采用工作记忆—视觉搜索双任务范式,探讨在非目标工作记忆表征下,颜色关联和抽象关联干扰子的注意捕获和抑制现象。实验一结果发现,颜色关联干扰子在快速反应阶段捕获注意,随后被成功抑制;抽象关联干扰子仍能捕获注意。实验二消除知觉凸显后,结果发现颜色关联条件的抑制消失,干扰子重新捕获注意。结果表明,有效抑制策略受不同关联干扰子加工先后顺序的影响,选择性抑制颜色关联干扰子,而颜色特征的凸显有助于抑制策略形成。     

Executive working memory load does not compromise perceptual processing during visual search: Evidence from additive factors analysis

Executive working memory (WM) load reduces the efficiency of visual search, but the mechanisms by which this occurs are not fully known. In the present study, we assessed the effect of executive load on perceptual processing during search. Participants performed a serial oculomotor search task, looking for a circle target among gapped-circle distractors. The participants performed the task under high and low executive WM load, and the visual quality (Experiment 1) or discriminability of targets and distractors (Experiment 2) was manipulated across trials. By the logic of the additive factors method (Sternberg, 1969, 1998), if WM load compromises the quality of perceptual processing during visual search, manipulations of WM load and perceptual processing difficulty should produce nonadditive effects. Contrary to this prediction, the effects of WM load and perceptual difficulty were additive. The results imply that executive WM load does not degrade perceptual analysis during visual search.     

Orienting attention in visual working memory reduces interference from memory probes

Given a changing visual environment, and the limited capacity of visual working memory (VWM), the contents of VWM must be in constant flux. Using a change detection task, the authors show that VWM is subject to obligatory updating in the face of new information. Change detection performance is enhanced when the item that may change is retrospectively cued 1 s after memory encoding and 0.5 s before testing. The retro-cue benefit cannot be explained by memory decay or by a reduction in interference from other items held in VWM. Rather, orienting attention to a single memory item makes VWM more resistant to interference from the test probe. The authors conclude that the content of VWM is volatile unless it receives focused attention, and that the standard change detection task underestimates VWM capacity.     

Automatic guidance of visual attention from verbal working memory

Previous studies have shown that visual attention can be captured by stimuli matching the contents of working memory (WM). Here, the authors assessed the nature of the representation that mediates the guidance of visual attention from WM. Observers were presented with either verbal or visual primes (to hold in memory, Experiment 1; to verbalize, Experiment 2; or merely to attend, Experiment 3) and subsequently were required to search for a target among different distractors, each embedded within a colored shape. In half of the trials, an object in the search array matched the prime, but this object never contained the target. Despite this, search was impaired relative to a neutral baseline in which the prime and search displays did not match. An interesting finding is that verbal primes were effective in generating the effects, and verbalization of visual primes elicited similar effects to those elicited when primes were held in WM. However, the effects were absent when primes were only attended. The data suggest that there is automatic encoding into WM when items are verbalized and that verbal as well as visual WM can guide visual attention.     

Visual working memory supports the inhibition of previously processed information: evidence from preview search

In four experiments we assessed whether visual working memory (VWM) maintains a record of previously processed visual information, allowing old information to be inhibited, and new information to be prioritized. Specifically, we evaluated whether VWM contributes to the inhibition (i.e., visual marking) of previewed distractors in a preview search. We evaluated this proposal by testing three predictions. First, Experiments 1 and 2 demonstrate that preview inhibition is more effective when the number of previewed distractors is below VWM capacity than above; an effect that can only be observed at small preview set sizes (Experiment 2A) and when observers are allowed to move their eyes freely (Experiment 2B). Second, Experiment 3 shows that, when quantified as the number of inhibited distractors, the magnitude of the preview effect is stable across different search difficulties. Third, Experiment 4 demonstrates that individual differences in preview inhibition are correlated with individual differences in VWM capacity. These findings provide converging evidence that VWM supports the inhibition of previewed distractors. More generally, these findings demonstrate how VWM contributes to the efficiency of human visual information processing--VWM prioritizes new information by inhibiting old information from being reselected for attention.     

The contents of visual working memory reduce uncertainty during visual search

Information held in visual working memory (VWM) influences the allocation of attention during visual search, with targets matching the contents of VWM receiving processing benefits over those that do not. Such an effect could arise from multiple mechanisms: First, it is possible that the contents of working memory enhance the perceptual representation of the target. Alternatively, it is possible that when a target is presented among distractor items, the contents of working memory operate postperceptually to reduce uncertainty about the location of the target. In both cases, a match between the contents of VWM and the target should lead to facilitated processing. However, each effect makes distinct predictions regarding set-size manipulations; whereas perceptual enhancement accounts predict processing benefits regardless of set size, uncertainty reduction accounts predict benefits only with set sizes larger than 1, when there is uncertainty regarding the target location. In the present study, in which briefly presented, masked targets were presented in isolation, there was a negligible effect of the information held in VWM on target discrimination. However, in displays containing multiple masked items, information held in VWM strongly affected target discrimination. These results argue that working memory representations act at a postperceptual level to reduce uncertainty during visual search.