Disentangling perceptual and motor components in inhibition of return

Following an abrupt onset of a peripheral stimulus (a cue), the response to a visual target is faster when the target appears at the cued position than when it appears at other positions. However, if the stimulus onset asynchrony (SOA) is longer than approximately 300 ms, the response to the target is slower at the cued position than that at other positions. This phenomenon of a longer response time to cued targets is called "inhibition of return" (IOR). Previous hypotheses propose contributions of both response inhibition and attentional inhibition at cued position to IOR, and suggest that responding to the cue can eliminate the component of response inhibition. The current study uses tasks either executing or withholding response to the cue to investigate the relative contributions of response and attention components to IOR. A condition with bilateral display of the cue is also chosen as a control condition, and eight different SOAs between 1,000 and 2,750 ms are tested. Compared to the control condition, response delay to the target at a cued position is eliminated by responding to the cue, and a response advantage to the target at an uncued position is not affected by responding to the cue. Furthermore, both response delay at a cued position and response advantage at an uncued position decrease with SOA in the time window tested in these experiments. The results reported here indicate a dominant response inhibition at a cued position and a primary attentional allocation at an uncued position for IOR. Nonsignificant perceptual/attentional suppression at a cued position is argued to be a benefit for visual detection in a changing world.     

不可信面孔在视知觉加工中的注意偏向：来自眼动的证据

使用眼动追踪技术探究个体对同时呈现的可信和不可信面孔的视知觉加工差异, 以及注意偏向与可信和不可信面孔的记忆关系。结果发现：(1)被试再认不可信面孔成绩要好于可信面孔; (2)首注视点更多地偏向于不可信面孔, 并且落在不可信面孔上的总注视时间/注视点个数更长/多; (3)回归分析表明首注视点偏向能预测不可信面孔的再认优势。结果表明人们对不可信面孔产生更多的注意警觉与维持, 并且对不可信面孔的警觉能预测不可信面孔的记忆优势。     

An emotional Stroop task with faces and words. A comparison of young and older adults

AntecedentsGiven the contradictions of previous studies on the changes in attentional responses produced in aging a Stroop emotional task was proposed to compare young and older adults to words or faces with an emotional valence.MethodThe words happy or sad were superimposed on faces that express the emotion of happiness or sadness. The emotion expressed by the word and the face could agree or not (cued and uncued trials, respectively). 85 young and 66 healthy older adults had to identify both faces and words separately, and the interference between the two types of stimuli was examined.ResultsAn interference effect was observed for both types of stimuli in both groups. There was more interference on positive faces and words than on negative stimuli.ConclusionsOlder adults had more difficulty than younger in focusing on positive uncued trials, whereas there was no difference across samples on negative uncued trials.     

Configural and contextual prioritization in object-based attention

When attention is directed to a location within an object, other locations within that object also enjoy an attentional advantage. Recently we demonstrated that this object-based advantage is mediated by increased attentional priority assigned to locations within an already attended object and not to early sensory enhancement due to the "spread" of attention within the attended object (Shomstein & Yantis, 2002). At least two factors might contribute to the assignment of attentional priority, one related to the configuration of objects in a scene and the other related to the probability of target appearance in each location imposed by task contingencies. We investigated the relative contribution of these factors by cuing one end of one of a pair of rectangles; a subsequent target appeared most often in the cued location. We manipulated attentional priority setting by varying (1) the probability that a target would appear in each of two uncued locations and (2) the cue to target stimulus onset asynchrony (SOA). On invalidly cued trials, the target appeared in the high-probability location (defined by an absolute spatial location, e.g., upper right) 83% of the time and in the low-probability location (e.g., lower left) 17% of the time. In both conditions, uncued targets appeared in the cued object half the time and in the uncued object half the time. At short SOAs, the same-object and probability effects were approximately additive. However, at longer SOAs, the same-object effects disappeared, and reaction times depended exclusively on location probability. These results suggest that observers adopt an implicit configural scanning strategy (in which unattended locations within an attended object have high priority) or an implicit contextual scanning strategy (in which objectively high-probability locations have high priority) depending on task contingencies and the amount of time that is available to deploy attention.     

Movement versus focusing of visual attention

In two experiments, we investigated the idea that attention moves through visual space in an analog fashion. The spatial distribution of attention was determined by presenting a spatially informative cue and comparing reaction times to targets at cued and uncued locations as a function of the interval from cue onset to target onset (SOA). Facilitation and inhibition were measured by reference to a neutral condition in which the cue provided no spatial information. In the first experiment, we used a central cue (an arrow), and in the second experiment, we used a peripheral cue (a 50-msec flash). With central cue, the facilitatory effects of the cuing were initially equal for all locations on the indicated side of the display, and then decreased for all locations except the one that had been specifically cued. These results are interpreted as being more consistent with "focusing" of an initially broad "beam" of attention than with "movement" of a narrow beam from fixation to the cued location. With peripheral cues, strong facilitation specific to the cued location was manifest as early as 50 msec after cue onset, but this effect decreased with increasing SOA. Inhibition for uncued locations increased with increasing SOA at a rate that generally reflected their distance from the cued location. Taken together, these results reveal important differences between peripheral and central cues in the generation of attentional selectivity, not just in the time-course of events, but also in the nature of the processes involved.     

自我威胁刺激对返回抑制的影响

使用线索-靶子范式,分别将面孔刺激作为线索(实验1)和靶子(实验2)呈现,考察自我扭曲面孔对返回抑制的影响。结果发现:自我扭曲面孔为线索时,与他人扭曲、他人中性面孔产生了实验性分离,自我扭曲面孔的返回抑制效应量最小;自我扭曲面孔为靶子时,返回抑制消失。研究结果揭示:以自我扭曲面孔为代表的自我威胁刺激激活了威胁性自我概念,缩小了注意搜索范围,可能是导致人际紧张的潜在自我认知机制。     

Task-irrelevant angry faces capture attention in visual search while modulated by resources

We investigated the attentional capture effect of emotional faces under sufficient or restricted attentional conditions. In a modified visual search paradigm, three kinds of schematic faces (angry, happy, and neutral) served as stimuli. Participants were instructed to search for a target face indicated by a dot and to respond to the dot's position. In this design, the emotional content of the face is task-irrelevant and does not need to be attended. The results of Experiment 1 demonstrate that having an angry face as the target face elicited a faster response than did the neutral target face, and when the angry face is used as a distractor, the response to the target was delayed compared to the response with no such distractor. Experiment 2 included inverted faces to decrease emotional content; results showed that inversion of the faces reduced the effect of angry faces on the search performance. When attention was cued to a specific area in Experiment 3, the effect of angry faces outside of the cued area became weaker. In conclusion, the results indicate that a task-irrelevant angry face can capture attention beyond top-down control, but this effect is modulated by the availability of attentional resources. (PsycINFO Database Record (c) 2011 APA, all rights reserved).     

Inhibition of object identity in inhibition of return: Implications for encoding and retrieving inhibitory processes

Inhibition of return (IOR) effects, in which participants detect a target in a cued box more slowly than one in an uncued box, suggest that behavior is aided by inhibition of recently attended irrelevant locations. To investigate the controversial question of whether inhibition can be applied to object identity in these tasks, in the present research we presented faces upright or inverted during cue and/or target sequences. IOR was greater when both cue and target faces were upright than when cue and/or target faces were inverted. Because the only difference between the conditions was the ease of facial recognition, this result indicates that inhibition was applied to object identity. Interestingly, inhibition of object identity affected IOR both whenencoding a cue face andretrieving information about a target face. Accordingly, we propose that episodic retrieval of inhibition associated with object identity may mediate behavior in cuing tasks.     

Learning about faces: effects of trustworthiness on affective evaluation

The results of two studies on the relationship between evaluations of trustworthiness, valence and arousal of faces are reported. In Experiment 1, valence and trustworthiness judgments of faces were positively correlated, while arousal was negatively correlated with both trustworthiness and valence. In Experiment 2, learning about faces based on their emotional expression and the extent to which this learning is influenced by perceived trustworthiness was investigated. Neutral faces of different models differing in trustworthiness were repeatedly associated with happy or with angry expressions and the participants were asked to categorize each neutral face as belonging to a "friend" or to an "enemy" based on these associations. Four pairing conditions were defined in terms of the congruency between trustworthiness level and expression: Trustworthy-congruent, trustworthy-incongruent, untrustworthy-congruent and untrustworthy-incongruent. Categorization accuracy during the learning phase and face evaluation after learning were measured. During learning, participants learned to categorize with similar efficiency trustworthy and untrustworthy faces as friends or enemies and thus no effects of congruency were found. In the evaluation phase, faces of enemies were rated as more negative and arousing than those of friends, thus showing that learning was effective to change the affective value of the faces. However, faces of untrustworthy models were still judged on average more negative and arousing than those of trustworthy ones. In conclusion, although face trustworthiness did not influence learning of associations between faces and positive or negative social information it did have a significant influence on face evaluation that was manifest even after that learning.     

Overt and covert object-based attention

To examine the role of perceptual object representations in the control of eye movements and attention, a pair of experiments adapted the object-cuing paradigm of Egly, Driver, and Rafal (1994) to require eye movements. Displays were pairs of adjacent rectangles, each containing two characters. Observers were asked to make a speeded judgment of a target character’s orientation, and a cue was provided prior to target/distractor onset to indicate the target’s likely location. Gaze-contingent presentation of target and distractors was used to demand overt scanning of displays. Eye movements during task performance evinced two forms of object-based effects. First, saccades following fixation on an invalidly cued item were more likely to be made within the cued rectangle than between rectangles. Second, saccades within the cued rectangle were preceded by shorter dwell times than saccades between rectangles. Extrafoveal processing of stimuli within the cued rectangle, however, was not facilitated, suggesting that covert attention was not allocated more densely within the cued than within the uncued object.     

阈下情绪面孔的注视线索提示效应

采用线索-靶子范式，利用2个预实验和1个正式实验，考察阈下不同情绪面孔的注视线索提示效应。要求被试在具有表情与注视线索的面孔呈现完毕后，快速而准确地对目标的位置进行判断。记录被试反应时间。结果显示，当被试未有意识的觉察到注视线索与面孔表情时，注视线索提示效应存在，并受到表情的调节。表现为：在注视线索有效并伴有恐惧表情时，被试对于目标的判断更加迅速；当比较不同表情下线索无效与线索有效条件下的反应时差异时发现，恐惧表情面孔出现时，线索无效与线索有效条件之间反应时的差异最大。结果表明，阈下情绪刺激能够激发个体更原始的生物性反应；在早期注意阶段，个体对于恐惧信息更加敏感，注意存在负向情绪偏差。     

Attention to faces modulates early face processing during low but not high face discriminability

In the present study, we investigated whether attention to faces results in sensory gain modulation. Participants were cued to attend either to faces or to scenes in superimposed face—scene images for which face discriminability was manipulated parametrically. The face-sensitive N170 event-related potential component was used as a measure of early face processing. Attention to faces modulated N170 amplitude, but only when faces were not highly discriminable. Additionally, directing attention to faces modulated later processing (~230—300 msec) for all discriminability levels. These results demonstrate that attention to faces can modulate perceptual processing of faces at multiple stages of processing, including early sensory levels. Critically, the early attentional benefit is present only when the “face signal” (i.e., the perceptual quality of the face) in the environment is suboptimal.     

Face‐Off: Facial Features and Strategic Choice

I study experimentally a single‐shot trust game where players have the opportunity to choose an avatar—a computer‐generated face—to represent them. These avatars vary on several dimensions—trustworthiness, dominance, and threat—identified by previous work as influencing perceptions of those who view the faces (Todorov, Said, Engell, & Oosterhof, 2008). I take this previous work and ask whether subjects choose faces that are ex ante more trustworthy, whether selected avatars have an influence on strategy choices, and whether individuals who evaluate faces as more trustworthy are also more likely to trust others. Results indicate affirmative answers to all three questions. Additional experimental sessions used randomly assigned avatars. This design allows me to compare behavior when everyone knows avatars are self‐selected versus when everyone knows they are randomly assigned. Random assignment eliminated all three effects observed when subjects chose their avatars.     

Object-based control of attention is sensitive to recent experience

How is attention guided by past experience? In visual search, numerous studies have shown that recent trials influence responses to the current trial. Repeating features such as color, shape, or location of a target facilitates performance. Here we examine whether recent experience also modulates a more abstract dimension of attentional control, object-based and location-based control. Participants performed a cued target discrimination task with stimuli presented on 2 rectangles. Response times to targets appearing in an uncued location on a cued rectangle were faster than to targets on the uncued rectangle, demonstrating an object-based attentional benefit. We investigated the object-based benefit on the current trial contingent on the cue-target relationship on the previous trial. The object-based benefit was significant only when the cued object contained the target on the previous trial, not when the uncued object contained the target. This effect of recent experience was not due to either the repetition of spatial cue-target location or the repetition of the response, but to adaptation to contingencies in the environment. Our results suggest a unifying view of attentional control that spans the concrete dimensions of control (e.g., determining the relative importance of red vs. blue) to the abstract (determining the relative importance of objects vs. locations in space). Attention closely tracks the short time scale structure of the environment and automatically adapts to optimize performance to this structure.     

Attentional momentum does not underlie the inhibition of return effect.

J. Pratt, T. M. Spalek, and F. Bradshaw (1999) recently proposed that attentional momentum is the mechanism underlying the inhibition of return (IOR) effect. They suggested that momentum associated with an attentional movement away from a peripherally cued location and toward an uncued opposite location is essential and fundamental to the finding of an IOR effect. Although it is clear from the present study and from a reanalysis of data from Pratt et al. that response time can be facilitated at an uncued opposite location, this putative effect of attentional momentum is neither robust nor reliable. First, it occurs for only a minority of participants. Second, it occurs in only a subset of the cued display positions. And finally, it is uncorrelated with the occurrence of IOR. Together the data indicate that the attentional momentum hypothesis is an overgeneralization and that it does not underlie the robust and reliable IOR effect.     

Attending to faces: change detection,familiarization, and inversion effects

We tested detection of changes to eye position, eye color (brightness), mouth position, and mouth color in frontal views of faces. Two faces were presented sequentially for 555 ms each, with a blank screen of 120 ms separating the two. Faces were presented either both upright or both inverted. Measures of detection (d') were calculated for several different degrees of change for each of the four dimensions of change. We first compared results to an earlier experiment that used an oddity design, in which subjects indicated which of three simultaneously viewed and otherwise identical faces had been altered on one of these four dimensions. Subjects in both of these experiments were partially cued, in that they knew the four possible types of changes that could occur on a given trial. The change-detection results correlated well with the oddity data. They confirmed that face inversion had little effect upon detection of changes in eye color, a moderate effect upon detection of eye-position or mouth-color changes, and caused a drastic reduction in the detection of mouth-position changes. An experiment in which uncued and fully cued subjects were compared showed that cueing significantly improved detection of feature color changes, but there was little difference between upright and inverted faces. Full cueing eliminated all effects of inversion. Compared to partial cueing, changes in mouth color were poorly detected by uncued subjects. Last, a change in the frequency of the base (unaltered) face in an experiment from 75% to 40% showed that increased short-term familiarity decreased the detection of eye changes and increased the detection of mouth changes, regardless of face orientation and the type of change made (color or position). We conclude that uncued subjects encode the spatial relations of features more than the colors of features, that mouth color in particular is not considered a relevant dimension for encoding, and that familiarization redistributes attention from more to less salient facial regions. Inversion effects are not simply an exaggeration of the salience effects revealed by withdrawing cueing, but represent an interaction of spatial encoding with salience, in that the greatest inversion effects occur for spatial shifts in less salient facial regions, and can be eliminated through the use of focused attention.     

Effects of response priming and inhibition on movement planning and execution

The authors used a precueing method to examine the effects of response priming and inhibition on goal-directed action. Participants (N = 18) completed aiming movements to 1 of 2 locations following predictive (80% cued), nonpredictive (50% cued), and antipredictive (20% cued) precues at 1 of the 2 possible target locations. Consistent with previous research, participants responded more quickly to targets at cued locations than to targets at uncued locations in the 80% condition, and more quickly to targets presented at the uncued than to those presented at cued locations in the 50% and 20% conditions. As predicted by models of action-centered selective attention, movement trajectories deviated away from the cued location in the 50% condition. Movement trajectories were also altered in the 80% and the 20% conditions. Movements directed to the uncued location deviated away from the cued location in the 80% condition, whereas movements directed to the cued location deviated away from the uncued location in the 20% condition. The authors explain the latter trajectory results as a strategy of overcompensation.     

Attentional bias to angry faces using the dot-probe task? It depends when you look for it

A number of studies using the dot-probe task now report the existence of an attentional bias to angry faces in participants who rate highly on scales of anxiety; however, no equivalent bias has been observed in non-anxious populations, despite evidence to the contrary from studies using other tasks. One reason for this discrepancy may be that researchers using the dot-probe task have rarely investigated any effects which might emerge earlier than 500 ms following presentation of the threat-related faces. Accordingly, in the current study we presented pairs of face stimuli with emotional and neutral expressions and probed the allocation of attention to these stimuli for presentation times of 100 and 500 ms. Results showed that at 100 ms there was an attentional bias towards the location of the relatively threatening stimulus (the angry face in angry/neutral pairs and the neutral face in neutral/happy pairs) and this pattern reversed by 500 ms. Comparisons of reaction time (RT) scores with an appropriate baseline suggested that the early bias toward threatening faces may actually arise through inhibition of the relatively least threatening member of a face pair rather than through facilitation of, or vigilance towards, the more threatening stimulus. However the mechanisms governing the observed biases are interpreted, these data provide evidence that probing for the location of spatial attention at 500 ms is not necessarily indicative of the initial allocation of attention between competing emotional facial stimuli.     

The flexibility of emotional attention: Accessible social identities guide rapid attentional orienting

There is extensive evidence that emotional-especially threatening-stimuli rapidly capture attention. These findings are often explained in terms of a hard-wired and relatively inflexible fear module. We propose an alternative, more flexible mechanism, arguing that motivational relevance is the crucial factor driving rapid attentional orienting. To test our hypothesis, we endowed initially neutral face stimuli with relevance by randomly assigning them to a social in-group or out-group during a 1-min learning phase, and used these faces as cues in a dot probe task to measure rapid attentional orienting. Across three experiments, we observed attentional orienting toward faces assigned to the out-group. Initial rapid orienting (after 100ms, Experiments 1 and 2) was observed only for familiar faces for which group membership was explicitly encoded, suggesting that rapid orienting may be based on affectively charged memory traces. At a later time point (after 500ms, Experiment 3), attention was deployed toward unfamiliar faces sharing a physical attribute (background color) with the familiar out-group faces, suggesting a more time-consuming on-line appraisal of the stimulus. The amount of attentional bias to out-group faces was correlated with individual differences in the accessibility of group identification. Our findings demonstrate that attentional prioritization mechanisms can be flexibly tuned by a brief learning phase of social identity. This is consistent with the idea that attention mechanisms subserving the selection and prioritization of emotional aspects of the environment are not static and hard-wired, but may rapidly adapt to recent changes in motivational contingencies.     

The relationship between covert and overt attention in endogenous cuing

In a standard Posner paradigm, participants were endogenously cued to attend to a peripheral location in visual space without making eye movements. They responded faster to target letters presented at cued than at uncued locations. On some trials, instead of a manual response, they had to move their eyes to a location in space. Results showed that the eyes deviated away from the validly cued location; when the cue was invalid and attention had to be allocated to the uncued location, eye movements also deviated away, but now from the uncued location. The extent to which the eyes deviated from cued and uncued locations was related to the dynamics of attention allocation. We hypothesized that this deviation was due to the successful inhibition of the attended location. The results imply that the oculomotor system is not only involved during the endogenous direction of covert attention to a cued location, but also when covert attention is directed to an uncued location. It appears that the oculomotor system is activated wherever spatial attention is allocated. The strength of saccade deviation might turn out to be an important measure for the amount of attention allocated to any particular location over time.