Eye movements reveal mechanisms underlying attentional biases towards threat

Mechanisms underlying attentional biases towards threat (ABTs), such as attentional avoidance and difficulty of disengagement, are still unclear. To address this issue, we recorded participants' eye movements during a dot detection task in which threatening or neutral stimuli served as peripheral cues. We evaluated response times (RTs) in trials where participants looked at the central fixation cross (not at the cues), as they were required, and number and duration of (unwanted) fixations towards threatening or neutral cues; in all analyses trait anxiety was treated as a covariate. Difficulty in attentional disengagement (longer RTs) was found when peripheral threatening stimuli were presented for 100?ms. Moreover, we observed significantly shorter (unwanted) fixations on threatening than on neutral peripheral stimuli, compatible with an avoidance bias, for longer presentation times. These findings demonstrate that, independent of trait anxiety levels, disengagement bias occurs without eye movements, whereas eye movements are implied in threat avoidance.     

Components of attentional bias to threat in high trait anxiety: Facilitated engagement, impaired disengagement, and attentional avoidance

There is a wealth of evidence demonstrating enhanced attention to threat in high trait anxious individuals (HTA) compared with low trait anxious individuals (LTA). In two experiments, we investigated whether this attentional bias is related to facilitated attentional engagement to threat or difficulties disengaging attention from threat. HTA and LTA undergraduates performed a modified exogenous cueing task, in which the location of a target was correctly or incorrectly cued by neutral, highly and mildly threatening pictures. Results indicate that at 100 ms picture presentation, HTA individuals more strongly engaged their attention with and showed impaired disengagement from highly threatening pictures than LTA individuals. In addition, HTA individuals showed a stronger tendency to attentional avoidance of threat at the 200 and 500 ms picture presentation. These data provide evidence for differential patterns of anxiety-related biases in attentive processing of threat at early versus later stages of information processing.     

Effects of induced and naturalistic mood on the temporal allocation of attention to emotional information

Building upon recent findings that affective states can influence the allocation of spatial attention, we investigate how state, trait and induced mood are related to the temporal allocation of attention to emotional information. In the present study, 125 unscreened undergraduates completed a modified rapid serial visual presentation task designed to assess the time course of attention to positive and negative information, comparing a neutral baseline mood induction to either a positive or negative mood induction. Induced negative mood facilitated attentional engagement to positive information while decreasing attentional engagement to negative information. Greater naturally occurring negative state mood was associated with faster or more efficient disengagement of attention from negative information in the presence of manipulated negative mood, relative to baseline. The engagement findings were inconsistent with our mood-congruence hypotheses and may be better explained by mood repair or affective counter-regulation theories. In contrast, the disengagement findings for state mood were somewhat consistent with our mood-congruence hypotheses. The relationship between mood and attention to emotional information may differ depending on the combination of attentional mechanism (engagement versus disengagement), aspect of mood (state, trait or induced), stimulus valence (positive versus negative) and timescale (early versus late) under investigation.     

空白重叠范式对自闭症儿童的早期预测

摘 要 空白重叠范式是研究视觉注意特征常用的实验范式。自闭症儿童普遍存在注意解离缺陷,空白重叠范式揭示出该群体注意解离存在异常。国外开始重视将该范式用于自闭症的预测,而我国在这方面的研究很少。本文对空白重叠范式的操作程序、基本原理和数据分析等内容进行了系统地介绍,并就空白重叠范式在自闭症婴幼儿预测中的作用、使用时需注意的方法论等问题进行了展望,以期促进空白重叠范式在我国自闭症早期预测中的运用。     

Components of attentional biases in contamination fear: Evidence for difficulty in disengagement

Attentional bias for threat has been implicated in the contamination fear (CF) subtype of obsessive-compulsive disorder, but the components of the bias (facilitated attention versus difficulty in disengagement) and the stage of processing during which the bias occurs (early versus late stage of processing) remains unclear. Further, it is unclear whether attentional biases in CF are towards fear or disgust-related stimuli. The present study examined attentional biases in a group of individuals selected to have elevated CF (n = 23) and a control group (n = 28) using the spatial cueing task. Stimuli were neutral, disgusting, or frightening pictures presented for either 100 or 500 ms. Results revealed evidence for delayed disengagement from both fear and disgust stimuli in the CF group, but not in the control group. The effect appeared to be greater at 500 ms stimulus presentation, but did not appear to differ between fear and disgust stimuli. The CF group was associated with delayed disengagement from threat even when controlling for generic response slowing. Theoretical and clinical implications are discussed.     

Viewing behavior: Ocular and attentional disengagement

In five experiments, we examined the role of the ocular and attentional systems in determining saccadic latencies. Prior to making a saccade to a target stimulus, subjects were required to direct their attention to a foveal stimulus or to an eccentric stimulus. Either stimulus could be extinguished before the onset of the target. Saccadic latencies were shortest when the foveal stimulus was extinguished, regardless of whether it was attended or not. Control experiments showed that subjects were able to attend properly and that warning, arising from turning off a stimulus before target onset, could not completely account for the results. The results were discussed in terms of ocular disengagement, attentional disengagement, and joint ocular-attentional disengagement. It was concluded that an explanation emphasizing ocular disengagement provided the best account of the data.     

The time-course of visual threat processing: High trait anxious individuals eventually avert their gaze from angry faces

Several experiments have shown that anxious individuals have an attentional bias towards threat cues. It is also known, however, that exposure to a subjectively threatening but relatively harmless stimulus tends to lead to a reduction in fear. Accordingly, some authors have hypothesised that high trait anxious individuals have a vigilant-avoidant pattern of visual attention to threatening stimuli. In the present study, 52 high trait anxious and 48 low trait anxious subjects were shown pairs of emotional faces, while their direction of gaze was continuously monitored. For 0-1000 ms, both groups were found to view angry faces more than happy faces. For 2000-3000 ms, however, only high trait anxious subjects averted their gaze from angry faces more than they did from happy faces.     

Vigilance for threat: effects of anxiety and defensiveness

Eysenck’s (1997) theory that attentional biases for threat vary as an interactive function of trait anxiety and defensiveness was tested using a visual probe task. Two stimulus exposure conditions were used to explore a secondary issue concerning attentional allocation over time. Results indicated that, among high trait anxious participants, only those with low levels of defensiveness showed vigilance for threatening faces presented for 500 ms. They also showed an attentional preference for neutral faces, relative to happy faces, irrespective of exposure condition. This pattern was reversed in high trait anxious participants with high levels of defensiveness, who showed an attentional bias towards happy faces (relative to neutral faces) under both exposure conditions. The findings are discussed in relation to their implications for (a) the significance of measures of defensiveness for the conceptualization of high trait anxious individuals, and (b) the status of anxiety-related biases at different stages of information processing.     

Attentional bias to brief threat-related faces revealed by saccadic eye movements

According to theories of emotion and attention, we are predisposed to orient rapidly toward threat. However, previous examination of attentional cueing by threat showed no enhanced capture at brief durations, a finding that may be related to the sensitivity of the manual response measure used. Here we investigated the time course of orienting attention toward fearful faces in the exogenous cueing task. Cue duration (20 ms or 100 ms) and response mode (saccadic or manual) were manipulated. In the saccade mode, both enhanced attentional capture and impaired disengagement from fearful faces were evident and limited to 20 ms, suggesting that saccadic cueing effects emerge rapidly and are short lived. In the manual mode, fearful faces impacted only upon the disengagement component of attention at 100 ms, suggesting that manual cueing effects emerge over longer periods of time. Importantly, saccades could reveal threat biases at brief cue durations consistent with current theories of emotion and attention.     

Interlateral asymmetry in the time course of the effect of a peripheral prime stimulus

Evidence exists that both right and left hemisphere attentional mechanisms are mobilized when attention is directed to the right visual hemifield and only right hemisphere attentional mechanisms are mobilized when attention is directed to the left visual hemifield. This arrangement might lead to a rightward bias of automatic attention. The hypothesis was investigated by testing male volunteers, wherein a "location discrimination" reaction time task (Experiments 1 and 3) and a "location and shape discrimination" reaction time task (Experiments 2 and 4) were used. Unilateral (Experiments 1 and 2) and unilateral or bilateral (Experiments 3 and 4) peripheral visual prime stimuli were used to control attention. Reaction time to a small visual target stimulus in the same location or in the horizontally opposite location was evaluated. Stimulus onset asynchronies (SOAs) were 34, 50, 67, 83 and 100 ms. An important prime stimulus attentional effect was observed as early as 50 ms in the four experiments. In Experiments 2, 3 and 4, this effect was larger when the prime stimulus occurred in the right hemifield than when it occurred in the left hemifield for SOA 100 ms. In Experiment 4, when the prime stimulus occurred simultaneously in both hemifields, reaction time was faster for the right hemifield and for SOA 100 ms. These results indicate that automatic attention tends to favor the right side of space, particularly when identification of the target stimulus shape is required.     

Reversal learning as a function of changed reward location or changed drive

In two experiments, rats were trained with food in one location (e.g., black alley) and water in another location (white alley) under hunger or thirst. Subsequently, either the locations of the rewards were reversed, or the drive was changed (from hunger to thirst or thirst to hunger). Reversal of instrumental responses took considerably longer when drive was changed and rewards remained in the same locations than when reward locations were reversed. These results were interpreted as indicating that the animal's internal representations of the rewards received in each location transfer when drive is changed. These internal-reward representations interfere with reversal learning by eliciting the responses which were conditioned to them in Phase 1. Because the values of food and water reverse when drive is changed from hunger to thirst or vice versa, it was suggested that the reward representations surviving the drive shift are cognitive representations of the specific events received (food or water), independent of the value of the rewards under either hunger or thirst.     

On the time course of exogenous cueing effects in bilinguals: higher proficiency in a second language is associated with more rapid endogenous disengagement

Previous investigations have demonstrated a bilingual advantage on various aspects of executive control. It remains unclear how the language proficiency of bilinguals might relate to the mechanisms involved in attentional disengagement. In the present investigation, we tested the hypothesis that high bilingual proficiency would lead to a more rapid endogenous disengagement of attention from task-irrelevant peripheral cues. We predicted that more rapid attentional disengagement would result in an earlier appearance of inhibition of return (IOR). In this study Hindi-English bilinguals who differed in their L2 (English) proficiency participated in a target detection task. Visual targets were preceded by uninformative peripheral cues at various stimulus onset asynchronies (SOAs) allowing for us to visualize the time course of cue-related facilitation and inhibition. High-proficient Hindi-English bilinguals showed an earlier appearance of IOR than did low-proficient bilinguals, suggesting increased efficiency in disengagement of attention from task-irrelevant inputs. Furthermore, consistent with the "global" advantage that characterizes bilinguals in many tasks, the high-proficient group outperformed low-proficient bilinguals in overall reaction time.     

Stimulus-driven and goal-driven effects on Pavlovian associative reward learning

It has been shown that pure Pavlovian associative reward learning can elicit value-driven attentional capture. However, in previous studies, task-irrelevant and response-independent reward-signalling stimuli hardly competed for visual selective attention. Here we put Pavlovian reward learning to the test by manipulating the extent to which bottom-up (Experiment 1) and top-down (Experiment 2) processes were involved in this type of learning. In Experiment 1, the stimulus, the colour of which signalled the magnitude of the reward given, was presented simultaneously with another randomly coloured stimulus, so that it did not capture attention in a stimulus-driven manner. In Experiment 2, observers performed an attentionally demanding RSVP-task at the centre of the screen to largely tax goal-driven attentional resources, while a task-irrelevant and response-independent stimulus in the periphery signalled the magnitude of the reward given. Both experiments showed value-driven attentional capture in a non-reward test phase, indicating that the reward-signalling stimuli were imbued with value during the Pavlovian reward conditioning phases. This suggests that pure Pavlovian reward conditioning can occur even when (1) competition prevents attention being automatically allocated to the reward-signalling stimulus in a stimulus-driven manner, and (2) attention is occupied by a demanding task, leaving little goal-driven attentional resources available to strategically select the reward-signalling stimulus. The observed value-driven attentional capture effects appeared to be similar for observers who could and could not explicitly report the stimulus–reward contingencies. Altogether, this study provides insight in the conditions under which mere stimulus–reward contingencies in the environment can be learned to affect future behaviour.     

Don’t let it distract you: how information about the availability of reward affects attentional selection

Previous research has shown that attentional selection is affected by reward contingencies: previously selected and rewarded stimuli continue to capture attention even if the reward contingencies are no longer in place. In the current study, we investigated whether attentional selection also is affected by stimuli that merely signal the magnitude of reward available on a given trial but, crucially, have never had instrumental value. In a series of experiments, we show that a stimulus signaling high reward availability captures attention even when that stimulus is and was never physically salient or part of the task set, and selecting it is harmful for obtaining reward. Our results suggest that irrelevant reward-signaling stimuli capture attention, because participants have learned about the relationship between the stimulus and reward. Importantly, we only observed learning after initial attentional prioritization of the reward signaling stimulus. We conclude that nonsalient, task-irrelevant but reward-signaling stimuli can affect attentional selection above and beyond top-down or bottom-up attentional control, however, only after such stimuli were initially prioritized for selection.     

自闭症谱系障碍个体的注意解离

注意解离是注意定向网络的重要组成部分, 指在注意转移过程中对原来刺激进行注意分离的过程。自闭症个体注意解离的早期受损会直接影响其它重要功能的发展, 尤其是唤醒调节和共同注意发展。采用间隙重叠范式的研究发现, 自闭症个体注意解离能力是否异常还存在争议, 被试年龄及取样、测量指标和刺激特征可能是影响的因素; 其神经机制可能涉及额叶、顶叶、小脑和胼胝体等脑区。未来应从脑机制研究入手, 综合考虑被试特征、研究方法和刺激特征对注意解离结果的影响, 明确其在自闭症早期预测和识别中的作用。     

Processing efficiency in anxiety: Evidence from eye-movements during visual search

It is generally held that anxiety is characterized by an attentional bias for threatening information. In recent years there has been an important debate whether these biases reside at the level of attentional selection (threat detection) or attentional processing after threat detection (attentional disengagement). In a visual search task containing emotional facial expressions, eye-movements were examined before and after threat detection in high and low trait anxious individuals to further elucidate the temporal unfolding of attentional bias. Results indicated that high-anxious individuals neither showed facilitated orienting to threat nor impaired disengagement of visual attention from threat. Interestingly, the presence of threat in the visual search display was associated with increased decision times in high-anxious individuals. These results challenge some of the current views on attentional bias to threat but indicate that emotional information reduces processing efficiency in anxiety.     

注意控制定势和线索类型在注意捕获中的作用

采用前线索范式, 通过3个实验考察了注意控制定势和线索类型在注意捕获中的作用。实验1要求被试搜索颜色奇异项目标或突现目标, 涉及较弱的注意控制定势, 结果表明, 突现线索在作为匹配线索和不匹配线索时都能捕获注意, 而颜色奇异项线索只有在作为匹配线索时才能捕获注意。实验2要求被试搜索具体特征的红色或白色目标, 使被试建立较强的特征搜索定势, 结果表明, 颜色奇异项线索和突现线索在作为匹配线索时都能捕获注意, 但是在不匹配条件下, 颜色奇异项线索被抑制了, 而突现线索不能捕获注意; 实验3采取go/no-go范式, 要求被试对红色目标进行反应, 对白色目标进行抑制, 并通过设置不同的线索-目标时间间隔来进一步考察注意捕获的机制, 结果表明, 在600 ms间隔下, no-go突现线索被抑制, 而对于go颜色奇异项线索来说, 随着时间间隔的增加, 注意捕获效应减少。结果与相倚捕获假说和抑制独立捕获假说不符, 支持注意转移假说：自上而下的注意控制定势通过把注意从和目标不匹配的特征位置转移发挥作用; 颜色奇异项线索和突现线索的注意捕获机制相同, 但是突现线索相对于颜色奇异项线索来说, 在与目标不匹配的条件下, 更容易捕获注意, 更难被抑制。     

内隐序列学习与注意负荷关系的实验研究

采用2(注意负荷:高、低)单因素被试内实验设计,以18名在校大学生为被试,运用行为实验及事件相关电位技术,对内隐序列学习是否需要注意负荷的参与进行实验研究。结果发现:(1)在高、低注意负荷条件下都出现了内隐序列学习效应;(2)高注意负荷序列探测刺激诱发的P1、N1波幅显著大于低注意负荷序列探测刺激诱发的,表明高注意负荷条件下需要更多的注意;(3)高、低注意负荷序列内隐序列学习量差异不显著,表明内隐序列学习不受注意负荷影响。     

奖赏预期对面孔情绪加工的影响：一项事件相关电位研究

采用事件相关电位(ERPs)技术考察了奖赏预期对人类面孔情绪识别的影响。实验采用线索-目标范式, 分别记录了被试在奖赏预期条件下以及无奖赏预期条件下对正性、中性和负性面孔进行情绪辨别任务的ERP数据。行为结果显示, 被试在奖赏预期条件下的反应时快于无奖赏预期条件下的反应时, 对情绪面孔的反应时快于对中性面孔的反应时。ERPs数据显示, 奖赏线索比无奖赏线索诱发了更正的P1、P2和P300成分。目标刺激诱发的P1、N170波幅以及N300均受到奖赏预期的调节, 在奖赏预期条件下目标诱发了更正的ERPs。P1、N170、VPP等成分没有受到面孔情绪的影响, 而额中央位置的N300波幅显示情绪(正性与负性)面孔与中性面孔加工的差异。重要的是, N300波幅出现奖赏预期与情绪的交互作用, 正、负情绪加工效应以及负性偏向效应受奖赏预期的差异性影响。正性情绪加工效应不受奖赏预期的影响, 而负性情绪加工效应和负性偏向效应在奖赏预期条件下显著大于无奖赏预期条件下。这些结果说明, 奖赏预期能够调节对面孔情绪的加工, 且不同加工进程中奖赏对情绪加工的调节作用不同。动机性信息调节注意资源的分配, 促进了个体在加工面孔情绪时的负性偏向。     

Selective attention to threat: A test of two cognitive models of anxiety

Two experiments evaluated differential predictions from two cognitive formulations of anxiety. According to one view, attentional biases for threat reflect vulnerability to anxiety; and as threat inputs increase, high trait anxious individuals should become more vigilant, and low trait individuals more avoidant, of threat (Williams, Watts, MacLeod, & Mathews, 1988, 1997). However, according to a “cognitive-motivational” view, trait anxiety influences the appraisal of stimulus threat value, rather than the direction of attentional bias, and both high and low trait anxious individuals should exhibit greater vigilance for high rather than mild threat stimuli (Mogg & Bradley, 1998). To test these predictions, two experiments examined the effect of manipulating stimulus threat value on the direction of attentional bias. The stimuli included high threat and mild threat pictorial scenes presented in a probe detection task. Results from both studies indicated a significant main effect of stimulus threat value on attentional bias, as there was increased vigilance or reduced avoidance of threat, as threat value increased. This effect was found even within low trait anxious individuals, consistent with the “cognitive-motivational” view. Theoretical and clinical implications are discussed.