Attentional sensitization of unconscious visual processing: Top-down influences on masked priming

Classical theories of automaticity assume that automatic processes elicited by unconscious stimuli are autonomous and independent of higher-level cognitive influences. In contrast to these classical conceptions, we argue that automatic processing depends on attentional amplification of task-congruent processing pathways and propose an attentional sensitization model of unconscious visual processing: According to this model, unconscious visual processing is automatic in the sense that it is initiated without deliberate intention. However, unconscious visual processing is susceptible to attentional top-down control and is only elicited if the cognitive system is configured accordingly. In this article, we describe our attentional sensitization model and review recent evidence demonstrating attentional influences on subliminal priming, a prototypical example of an automatic process. We show that subliminal priming (a) depends on attentional resources, (b) is susceptible to stimulus expectations, (c) is influenced by action intentions, and (d) is modulated by task sets. These data suggest that attention enhances or attenuates unconscious visual processes in congruency with attentional task representations similar to conscious perception. We argue that seemingly paradoxical, hitherto unexplained findings regarding the automaticity of the underlying processes in many cognitive domains can be easily accommodated by our attentional sensitization model. We conclude this review with a discussion of future research questions regar-ding the nature of attentional control of unconscious visual processing.     

Multiple Factors and Multiple Mechanisms Determine the Quality of Conscious Experiences: A Reply to Anzulewicz and Wierzchoń

In this Letter to the Editor, we seize the opportunity to respond to the recent comments by Anzulewicz and Wierzchoń, and further clarify and extend the scope of our original paper. We re‐emphasize that conscious experiences come in degrees, and that there are several factors that determine this degree. Endorsing the suggestions of Anzulewicz and Wierzchoń, we discuss that besides low‐level attentional mechanisms, high‐level attentional and non‐attentional mechanisms might also modulate the quality of conscious experiences.     

Repetition blindness is immune to the central bottleneck

Theattentional blink (AB) andrepetition blindness (RB) phenomena refer to subjects’ impaired ability to detect the second of two different (AB) or identical (RB) target stimuli in a rapid serial visual presentation stream if they appear within 500 msec of one another. Despite the fact that the AB reveals a failure of conscious visual perception, it is at least partly due to limitations at central stages of information processing. Do all attentional limits to conscious perception have their locus at this central bottleneck? To address this question, here we investigated whether RB is affected by online response selection, a cognitive operation that requires central processing. The results indicate that, unlike the AB, RB does not result from central resource limitations. Evidently, temporal attentional limits to conscious perception can occur at multiple stages of information processing.     

颜色字词的识别真的无需注意力资源的参与?——来自Stroop范式的证据

3个实验采用颜色词、颜色词同音词以及颜色语义联想词作为启动词,使启动词的语义和颜色实现时空分离、启动词处于非空间注意焦点位置、降低启动词可视度的情境下,考察具有自动化加工特征的启动词是否受到注意力资源的制约以及启动词在获得不同数量的注意力资源时其自动化程度是否存在显著的差异。结果发现:(1)注意力资源实质性地决定着自动化加工能否顺利进行,具有自动激活特征的刺激在无法获得注意力资源时,自动化加工过程终止。(2)可用的注意力资源数量调控着自动化加工的效率和语义提取的效果,可用的注意力资源数量越多,对启动刺激的语义加工越完善,对目标刺激的促进效果也越有效。本研究结果支持注意力敏感模型关于自动化加工受认知系统的支持和配置才能完成的假设。     

Do conscious perception and unconscious processing rely on independent mechanisms? A meta-contrast study

There is currently no consensus regarding what measures are most valid to demonstrate perceptual processing without awareness. Likewise, whether conscious perception and unconscious processing rely on independent mechanisms or lie on a continuum remains a matter of debate. Here, we addressed these issues by comparing the time courses of subjective reports, objective discrimination performance and response priming during meta-contrast masking, under similar attentional demands. We found these to be strikingly similar, suggesting that conscious perception and unconscious processing cannot be dissociated by their time course. Our results also demonstrate that unconscious processing, indexed by response priming, occurs, and that objective discrimination performance indexes the same conscious processes as subjective visibility reports. Finally, our results underscore the role of attention by showing that how much attention the stimulus receives relative to the mask, rather than whether processing is measured by conscious discrimination or by priming, determines the time course of meta-contrast masking.     

A dissociation between selective attention and conscious awareness in the representation of temporal order information

Previous electrophysiological studies have shown that attentional selection processes are highly sensitive to the temporal order of task-relevant visual events. When two successively presented colour-defined target stimuli are separated by a stimulus onset asynchrony (SOA) of only 10 ms, the onset latencies of N2pc components to these stimuli (which reflect their attentional selection) precisely match their objective temporal separation. We tested whether such small onset differences are accessible to conscious awareness by instructing participants to report the category (letter or digit) of the first of two target-colour items that were separated by an SOA of 10, 20, or 30 ms. Performance was at chance level for the 10 ms SOA, demonstrating that temporal order information which is available to attentional control processes cannot be utilized for conscious temporal order judgments. These results provide new evidence that selective attention and conscious awareness are functionally separable, and support the hypothesis that attention and awareness operate at different stages of cognitive processing.     

Temporal binding and the neural correlates of sensory awareness

Theories of binding have recently come into the focus of the consciousness debate. In this review, we discuss the potential relevance of temporal binding mechanisms for sensory awareness. Specifically, we suggest that neural synchrony with a precision in the millisecond range may be crucial for conscious processing, and may be involved in arousal, perceptual integration, attentional selection and working memory. Recent evidence from both animal and human studies demonstrates that specific changes in neuronal synchrony occur during all of these processes and that they are distinguished by the emergence of fast oscillations with frequencies in the gamma-range.     

The levels of perceptual processing and the neural correlates of increasing subjective visibility

According to the levels-of-processing hypothesis, transitions from unconscious to conscious perception may depend on stimulus processing level, with more gradual changes for low-level stimuli and more dichotomous changes for high-level stimuli. In an event-related fMRI study we explored this hypothesis using a visual backward masking procedure. Task requirements manipulated level of processing. Participants reported the magnitude of the target digit in the high-level task, its color in the low-level task, and rated subjective visibility of stimuli using the Perceptual Awareness Scale. Intermediate stimulus visibility was reported more frequently in the low-level task, confirming prior behavioral results. Visible targets recruited insulo-fronto-parietal regions in both tasks. Task effects were observed in visual areas, with higher activity in the low-level task across all visibility levels. Thus, the influence of level of processing on conscious perception may be mediated by attentional modulation of activity in regions representing features of consciously experienced stimuli.     

Assessing the role of spatial engagement and disengagement of attention in anxiety-linked attentional bias: a critique of current paradigms and suggestions for future research directions

A considerable volume of research has demonstrated an anxiety-linked attentional bias characterized by selective processing of threat stimuli. The last decade has seen growing interest in identifying the precise attentional mechanisms which underlie such selective processing to advance both theoretical and etiological models of anxiety. This research has particularly focused on the roles of spatial engagement and disengagement of attention. The relative contribution of these attentional components to selective processing of threat in anxious individuals remains unclear however. Moreover, we argue here that many of the tasks employed to examine these mechanisms, may not be capable of indexing the attentional processes that they claim to measure. In this article, we provide a methodological review, critically evaluating the adequacy of previous tasks employed to measure biased attentional engagement and disengagement. Based on a number of concerns raised about the ability of such tasks to differentiate these component attentional processes, we detail three task criteria that we believe are essential to be confident that a task will accurately index biased attentional engagement with, and disengagement from threat in anxious participants.     

Nonconscious perception, conscious awareness and attention

Because it is unclear how a nonconscious stimulus is cognitively processed, there is uncertainty concerning variables that modulate the processing. In this context recent findings of a set of neuroimaging experiments are important. These findings suggest that conscious and nonconscious stimuli activate same areas of the brain during performance of a similar task. Further, different areas are activated when a task is performed with or without awareness of processing. It appears that the neural network involved in cognitive processing depends on the awareness of processing rather than awareness of perception. Since conscious and nonconscious cognitive processing use separate neural networks, each processing is modulated by different variables. Attention modulates most conscious cognitive processing and most, but not all, nonconscious processing is attention dependent. Nonconscious tasks that require attentional resources, with or without conscious awareness, are processed using the attention dependent system. Further, because attention dependent and attention independent tasks are processed by separate neural networks, the cognitive processing and modulating variables can be understood better if cognitive tasks are defined as attention dependent or attention independent, rather than conscious or nonconscious.     

The attentional blink unveils the interplay between conscious perception,spatial attention and working memory encoding

Our ability to perceive two events in close temporal succession is severely limited, a phenomenon known as the attentional blink. While the blink has served as a popular tool to prevent conscious perception, there is less research on its causes, and in particular on the role of conscious perception of the first event in triggering it. In three experiments, we disentangled the roles of spatial attention, conscious perception and working memory (WM) in causing the blink. We show that while allocating spatial attention to T1 is neither necessary nor sufficient for eliciting a blink, consciously perceiving it is necessary but not sufficient. When T1 was task irrelevant, consciously perceiving it triggered a blink only when it matched the attentional set for T2. We conclude that consciously perceiving a task-relevant event causes the blink, possibly because it triggers encoding of this event into WM. We discuss the implications of these findings for the relationship between spatial attention, conscious perception and WM, as well as for the distinction between access and phenomenal consciousness.     

人工语法学习中意识加工的渐进发展

内隐学习研究致力于探讨学习活动的意识加工程度, 当前相关的研究逻辑从传统的意识二分观转向渐进意识假设。本研究通过对人工语法范式进行改造, 并借鉴加工分离程序的有关思想, 在学习阶段引入双重测量任务, 并根据双重任务成绩计算分离出相应学习时段的意识与无意识成分的贡献分数, 从而考察在内隐学习过程中两种加工成分的动态变化特征。研究结果支持渐进意识假设, 在学习进程中, 无意识成分和意识成分都呈现出渐进发展的趋势; 而随学习的深入, 两种成分呈现出不同的变化模式, 中后期意识加工快速增长, 无意识加工则保持平缓发展, 渐进意识系统整体呈现向外显学习推进的发展态势。     

When endogenous spatial attention improves conscious perception: Effects of alerting and bottom-up activation

Recent studies have consistently demonstrated that conscious perception interacts with exogenous attentional orienting, but it can be dissociated from endogenous attentional orienting (Chica, Lasaponara, et al., 2011, Wyart and Tallon-Baudry, 2008). It has been hypothesized that enhanced conscious processing at exogenously attended locations results from a synergistic action of spatial orienting, bottom-up activation, and phasic alerting induced by the abrupt onset of the exogenous cue (Chica, Lasaponara, et al., 2011). Instead, as endogenous cues need more time to be interpreted, the phasic alerting they produce may have dissipated when the target appears. Furthermore, endogenous cues presumably elicit a weak bottom-up activation at the cued location. Consistent with these hypotheses, we observed that endogenous attention modulated conscious perception, but only when phasic alerting or bottom-up activation was increased. Results are discussed in the context of recent theoretical models of consciousness (Dehaene, Changeux, Naccache, Sackur, & Sergent, 2006).     

Retrospective perceptual distortion of position representation does not lead to delayed localization

Previous studies have reported retrospective influences of visual events that occur after target events. In the attentional attraction effect, a position cue presented after a target stimulus distorts the target’s position towards that of the cue. The present study explored the temporal relationship between stimulus presentation and reaction time (RT) in this effect in two experiments. Participants performed a speeded localization task on two vertical lines, the positions of which were to be distorted by an additional attentional cue. No significant difference in RTs was found between the conditions with simultaneous and delayed cues. RTRT was modulated by the perceived (rather than physical) alignment of the lines. In Experiment 2, we manipulated the strength of attentional capture by modulating the color relevance of the cue to the target. Trials with cues producing stronger attentional capture (with cues of a different color from the targets) were found to induce apparently stronger distortion effects. This result favors the notion that the observed repulsion and attraction effects are driven by attentional mechanisms. Overall, the results imply that the attentional shift induced by the cue might occur rapidly and complete before the establishment of conscious location representation of the cue and the target without affecting overall response time.     

On the Functional Role of Implicit Visual Memory for the Adaptive Deployment of Attention Across Scenes

Although very little visual information is explicitly retained across views, some continuity of processing is afforded by implicit visual memory traces of previous views. These memory traces interact with attentional mechanisms to guide eye movements, cognition, and action. Two different memory mechanisms are described here. First, the deployments of focal attention and eye movements are facilitated towards recently attended features and locations (priming of popout). Second, attention is guided by implicit memory traces of specific visual contexts experienced in the past (contextual cueing). Compared to the visual memory tapped by change blindness tasks, the implicit memory mechanisms of priming of popout and contextual cueing do not require conscious intervention and may exhibit greater memory capacity, longer durability, and higher discriminability. Thus, these implicit traces of past views guide attention and eye movements to allow for effective access (indexing) to a scene's details, hence providing context and continuity to ongoing interactions with the perceptual world.     

A presentation of Attentional Semantics

The paper presents the two main assumptions of Attentional Semantics—(A) and (B), and its main aim (C). (A) Conscious experience is determined by attention: there cannot be consciousness without attention. Consciousness is explained as the product of attentional activity. Attentional activity can be performed thanks to a special kind of energy: nervous energy. This energy is supplied by the organ of attention. When we perform attentional activity, we use our nervous energy. This activity directly affects the organ of attention, causing a variation in the state of the nervous energy. This variation constitutes the phenomenal aspect of consciousness. (B) Words are tools to pilot attention. The meanings of words isolate, de-contextualize, “freeze” and classify in an articulated system the ever-changing and multiform stream of our conscious experiences. Each meaning is composed of the sequence of invariable elements that, independently of any individual occurrence of a given conscious experience, are responsible for the production of any instance of that conscious experience. The elements composing the meanings of words are attentional operations: each word conveys the condensed instructions on the attentional operations one has to perform if one wants to consciously experience what is expressed through and by it. (C) Attentional Semantics aims at finding the attentional instruction conveyed by the meanings of words. To achieve this goal, it tries: (1) to identify the sequence of the elementary conscious experiences that invariably accompany, and are prompted by, the use of the word being analyzed; (2) to describe these conscious experiences in terms of the attentional operations that are responsible for their production; and (3) to identify the unconscious and non-conscious operations that, directly or indirectly, serve either as the support that makes it possible for the attentional operations to take place, be completed, and occur in a certain way, or as the necessary complement that makes it possible to execute and implement the activities determined and triggered by the conscious experiences. The origins of Attentional Semantics are also presented, and the methodological problems researchers encounter when analyzing meanings in attentional terms are discussed. Finally, a brief comparison with the other kinds of semantics is made.     

无意视盲的认知神经机制

无意视盲现象是指即使某些刺激物出现在视野中, 观察者也并没有觉察到这些刺激物的存在。这种现象在我们的现实生活中普遍存在, 它是许多交通和医疗事故的罪魁祸首。回顾前人的研究结果我们发现, 从认知行为角度出发, 无意视盲主要由两方面原因引起, 即“资源有限”与“注意定势”。一般情况下, “资源有限”与“注意定势”会共同导致无意视盲; 但有时候, “注意定势”也会独立于“资源有限”直接导致无意视盲。另外, 从大脑神经机制的角度来看, “资源有限”与“注意定势”作用于大脑加工的中后期, 即使产生无意视盲, 意识加工脑区对非预期刺激也进行了一定的认知加工, 但是否能进入到意识层面, 一方面取决于刺激呈现后中期枕顶部位的意识输入, 另一方面取决于与刺激驱动相关的颞顶联合区的激活程度以及与记忆负荷相关的顶内沟的抑制程度。     

Processing of emotional meaning in anxiety

Abstract

Previous research has indicated that anxiety and depressive states do not lead to speeding of lexical decisions for mood-congruent words. Theoretical considerations, and some data, suggest that such mood-congruent speeding effects should be more apparent in affective decisions. In three experiments we found no evidence that anxious subjects are faster when making affective decisions for congruent (threatening) words, whether or not these subjects had been recently exposed to the same words. It is concluded that the processes involved in the attentional and interpretive processing of threatening stimuli by anxious subjects are different from those involved when making a conscious decision about emotional meaning.     

Surprise-induced blindness: a stimulus-driven attentional limit to conscious perception

The cost of attending to a visual event can be the failure to consciously detect other events. This processing limitation is well illustrated by the attentional blink paradigm, in which searching for and attending to a target presented in a rapid serial visual presentation stream of distractors can impair one's ability to detect a second target presented soon thereafter. The attentional blink critically depends on 'top-down' attentional settings, for it does not occur if participants are asked to ignore the first target. Here we show that 'bottom-up' attention can also lead to a profound but ephemeral deficit in conscious perception: Presentation of a novel, unexpected, and task-irrelevant stimulus virtually abolishes conscious detection of a target presented within half a second after the 'Surprise' stimulus, but only for its earliest occurrences (generally 1 to 2 presentations). This powerful but short-lived deficit contrasts with a milder but more enduring form of attentional capture that accompanies singleton presentations in rapid serial visual presentations. We conclude that the capture of stimulus-driven attention alone can limit explicit perception.     

工作记忆负荷、形状干扰对聋人与听力正常人注意捕获影响的眼动研究

通过记录和分析被试的行为和眼动指标,本研究试图探讨不同工作记忆负荷下,形状干扰对聋人与听力正常人不同视野位置上刺激信息捕获注意的异同。研究结果表明：（1）形状干扰刺激虽然没有影响被试视觉加工的认知绩效,但被试的眼动模式会由于工作记忆负荷的改变而改变,高工作记忆负荷时,有形状干扰的注视次数高于无形状干扰。（2）工作记忆负荷、视野位置影响被试视觉加工任务的完成,被试在不同视野位置的加工过程表现出不一致的眼动模式。（3）聋人视觉加工在高工作记忆负荷时存在一定的劣势,但其对不同视野位置的信息加工及形状干扰所产生的注意捕获效应与听力正常人一致。