Task-irrelevant direct gaze facilitates visual search for deviant facial expression

The detection of emotional expression is important particularly when the expression is directed towards the viewer. Therefore, we conjectured that the efficiency in visual search for deviant emotional expression is modulated by gaze direction, which is one of the primary clues for encoding the focus of social attention. To examine this hypothesis, two visual search tasks were conducted. In Emotional Face Search, the participants were required to detect an emotional expression amongst distractor faces with neutral expression; in Neutral Face Search they were required to detect a neutral target among emotional distractors. The results revealed that target detection was accelerated when the target face had direct gaze compared to averted gaze for fearful, angry, and neutral targets, but no effect of distractor gaze direction was observed. An additional experiment including multiple display sizes has shown a shallower search slope in search for a target face with direct gaze than that with averted gaze, indicating that the advantage of a target face with direct gaze is attributable to efficient orientation of attention towards target faces. These results indicate that direct gaze facilitates detection of target face in visual scenery even when gaze discrimination is not the primary task at hand.     

视觉搜索任务中直视探测优势的眼动研究

已有研究发现在视觉搜索任务中对直视的探测比斜视更快且更准确, 该现象被命名为“人群中的凝视效应”。大多数研究者将该效应的产生归因于直视会捕获更多的注意。然而, 直视条件下对搜索项的匹配加工更容易也有可能导致对直视的探测比斜视快。此外,已有研究还发现头的朝向会影响对注视方向的探测, 但对于其产生原因缺乏实验验证。本研究采用视觉搜索范式, 运用眼动技术, 把注视探测的视觉搜索过程分为准备阶段、搜索阶段和反应阶段, 对这两个问题进行了探讨。结果显示：对直视的探测优势主要表现在搜索阶段和反应阶段; 在搜索阶段直视的探测优势获益于搜索路径的变短和分心项数量的变少以及分心项平均注视时间的变短; 头的朝向仅在搜索阶段对注视探测产生影响。该结果表明, 在直视探测中对搜索项的匹配加工比在斜视探测中更容易也是导致“人群中的凝视效应”的原因之一; 头的朝向仅仅影响了对注视方向的搜索并没有影响对其的确认加工。     

Effects of peripheral eccentricity and head orientation on gaze discrimination

Visual search tasks support a special role for direct gaze in human cognition, while classic gaze judgement tasks suggest the congruency between head orientation and gaze direction plays a central role in gaze perception. Moreover, whether gaze direction can be accurately discriminated in the periphery using covert attention is unknown. In the present study, individual faces in frontal and in deviated head orientations with a direct or an averted gaze were flashed for 150 ms across the visual field; participants focused on a centred fixation while judging the gaze direction. Gaze discrimination speed and accuracy varied with head orientation and eccentricity. The limit of accurate gaze discrimination was less than ±6° eccentricity. Response times suggested a processing facilitation for direct gaze in fovea, irrespective of head orientation, however, by ±3° eccentricity, head orientation started biasing gaze judgements, and this bias increased with eccentricity. Results also suggested a special processing of frontal heads with direct gaze in central vision, rather than a general congruency effect between eye and head cues. Thus, while both head and eye cues contribute to gaze discrimination, their role differs with eccentricity.     

Look at them and they will notice you: Distractor-independent attentional capture by direct gaze in change blindness

Humans have shown a detection advantage of direct vs. averted gaze stimuli in visual search tasks. However, instead of attentional capture by direct gaze, the detection advantage in visual search may depend on attention-grabbing potential of the distractor stimuli to which the target needs to be compared. We investigated attentional capture by direct gaze using the change blindness paradigm, in which successful detection does not require comparison between the target and the distractor items. Participants detected a masked gaze direction change in one of four simultaneously presented schematic faces. The distractor gaze directions were systematically varied across three experiments. Changes resulting in direct gaze were detected more efficiently than those resulting in averted gaze, independently of distractor gaze directions. This finding suggests that the detection advantage is specifically due to attentional capture by direct gaze, not properties of distractor items.     

Effects of perceived mutual gaze and gender on face processing and recognition memory

Perceived gaze contact in seen faces may convey important social signals. We examined whether gaze perception affects face processing during two tasks: Online gender judgement, and later incidental recognition memory. Individual faces were presented with eyes directed either straight towards the viewer or away, while these faces were seen in either frontal or three-quarters view. Participants were slower to make gender judgements for faces with direct versus averted eye gaze, but this effect was particularly pronounced for faces with opposite gender to the observer, and seen in three-quarters view. During subsequent surprise recognition-memory testing, recognition was better for faces previously seen with direct than averted gaze, again especially for the opposite gender to the observer. The effect of direct gaze was stronger in both tasks when the head was seen in three-quarters rather than in frontal view, consistent with the greater salience of perceived eye contact for deviated faces. However, in the memory test, face recognition was also relatively enhanced for faces of opposite gender in front views when their gaze was averted rather than direct. Together, these results indicate that perceived eye contact can interact with facial processing during gender judgements and recognition memory, even when gaze direction is task-irrelevant, and particularly for faces of opposite gender to the observer (an influence which controls for stimulus factors when considering observers of both genders). These findings appear consistent with recent neuroimaging evidence that social facial cues can modulate visual processing in cortical regions involved in face processing and memory, presumably via interconnections with brain systems specialized for gaze perception and social monitoring.     

Detection of emotional faces: salient physical features guide effective visual search

In this study, the authors investigated how salient visual features capture attention and facilitate detection of emotional facial expressions. In a visual search task, a target emotional face (happy, disgusted, fearful, angry, sad, or surprised) was presented in an array of neutral faces. Faster detection of happy and, to a lesser extent, surprised and disgusted faces was found both under upright and inverted display conditions. Inversion slowed down the detection of these faces less than that of others (fearful, angry, and sad). Accordingly, the detection advantage involves processing of featural rather than configural information. The facial features responsible for the detection advantage are located in the mouth rather than the eye region. Computationally modeled visual saliency predicted both attentional orienting and detection. Saliency was greatest for the faces (happy) and regions (mouth) that were fixated earlier and detected faster, and there was close correspondence between the onset of the modeled saliency peak and the time at which observers initially fixated the faces. The authors conclude that visual saliency of specific facial features--especially the smiling mouth--is responsible for facilitated initial orienting, which thus shortens detection. (PsycINFO Database Record (c) 2008 APA, all rights reserved).     

Gaze direction and facial expressions exert combined but different effects on attentional resources

Gaze direction and facial expressions are critical components of face processing and have been shown to influence attention deployment. We investigated whether gaze direction (direct vs. averted) combined with a neutral or angry expression modulates the deployment of attentional resources over time. In a Rapid Serial Visual Presentation (RSVP) paradigm participants had to decide the gender of a neutral or an angry target face with direct or averted gaze (T1) and then to judge the orientation of a target picture of a landscape (T2), following the face at different time intervals. Results showed no attentional blink effect (i.e., no deterioration in T2 accuracy) when T1 was an angry face with direct gaze, whereas it was present for angry faces with averted gaze or neutral faces with either averted or direct gaze. These findings are consistent with appraisal theories and are discussed against the background of automatic processing of threat stimuli.     

Gaze direction and facial expressions exert combined but different effects on attentional resources

Gaze direction and facial expressions are critical components of face processing and have been shown to influence attention deployment. We investigated whether gaze direction (direct vs. averted) combined with a neutral or angry expression modulates the deployment of attentional resources over time. In a Rapid Serial Visual Presentation (RSVP) paradigm participants had to decide the gender of a neutral or an angry target face with direct or averted gaze (T1) and then to judge the orientation of a target picture of a landscape (T2), following the face at different time intervals. Results showed no attentional blink effect (i.e., no deterioration in T2 accuracy) when T1 was an angry face with direct gaze, whereas it was present for angry faces with averted gaze or neutral faces with either averted or direct gaze. These findings are consistent with appraisal theories and are discussed against the background of automatic processing of threat stimuli.     

Is anyone looking at me? Direct gaze detection in children with and without autism

Atypical processing of eye contact is one of the significant characteristics of individuals with autism, but the mechanism underlying atypical direct gaze processing is still unclear. This study used a visual search paradigm to examine whether the facial context would affect direct gaze detection in children with autism. Participants were asked to detect target gazes presented among distracters with different gaze directions. The target gazes were either direct gaze or averted gaze, which were either presented alone (Experiment 1) or within facial context (Experiment 2). As with the typically developing children, the children with autism, were faster and more efficient to detect direct gaze than averted gaze, whether or not the eyes were presented alone or within faces. In addition, face inversion distorted efficient direct gaze detection in typically developing children, but not in children with autism. These results suggest that children with autism use featural information to detect direct gaze, whereas typically developing children use configural information to detect direct gaze.     

Monitoring eye movements while searching for affective faces

A single experiment is reported in which we provide a novel analysis of eye movements during visual search to disentangle the contributions of unattended guidance and focal target processing to visual search performance. This technique is used to examine the controversial claim that unattended affective faces can guide attention during search. Results indicated that facial expression influences how efficiently the target was fixated for the first time as a function of set size. However, affective faces did not influence how efficiently the target was identified as a function of set size after it was first fixated. These findings suggest that, in the present context, facial expression can influence search before the target is attended and that the present measures are able to distinguish between the guidance of attention by targets and the processing of targets within the focus of attention.     

Straight gaze facilitates face processing but does not cause involuntary attentional capture

This study aimed to investigate the conditions under which eyes with a straight gaze capture attention more than eyes with an averted gaze, a phenomenon called the stare-in-the-crowd effect. In Experiment 1, we measured attentional capture by distractor faces with either straight or averted gaze that were shown among faces with closed eyes. Gaze direction of the distractor face was irrelevant because participants searched for a tilted face and indicated its gender. The presence of the distractor face with open eyes resulted in slower reaction times, but gaze direction had no effect, suggesting that straight gaze does not result in more involuntary attentional capture than averted gaze. In three further experiments with the same stimuli, the gaze direction of the target, and not the distractor, was varied. Better performance with straight than averted gaze of the target face was observed when the gaze direction or gender of the target face had to be discriminated. However, no difference between straight and averted was observed when only the presence of a face with open eyes had to be detected. Thus, the stare-in-the crowd effect is only observed when eye gaze is selected as part of the target and only when features of the face have to be discriminated. Our findings suggest that preference for straight gaze bears on target-related processes rather than on attentional capture per se.     

Direct gaze,eye movements,and covert and overt social attention processes

The present study is a replication and extension of previous research examining the effects of others’ gaze direction and gaze shifts on both participants’ (N = 32) manual responses, as an indicator of covert processes, and their visual attention, as an indicator of overt processes, within an experimental response time (RT) paradigm, under both fixed- and free-viewing instructions. Participants viewed arrays of faces displaying direct or averted gaze, which shifted or held their gaze, concurrent with the presentation of a target letter that participants had to identify overlaid on one face, all while their gaze was recorded with an eye-tracking system. Participants’ RTs and eye movements both revealed faster responses when the target face displayed either direct or shifted gaze, and especially when its gaze had shifted from averted to direct, though these effects were modulated by the viewing instructions. Thus, the findings replicate and extend previous research by revealing that direct gaze and dynamic motion onset affect both covert and overt attention.     

Direct gaze captures visuospatial attention

This study investigated whether the direct gaze of others influences attentional disengagement from faces in an experimental situation. Participants were required to fixate on a centrally presented face with varying gaze directions and to detect the appearance of a peripheral target as quickly as possible. Results revealed that target detection was delayed when the preceding face was directly gazing at the subject (direct gaze), as compared with an averted gaze (averted gaze) or with closed eyes (closed eyes). This effect disappeared when a temporal gap was inserted between the offset of the centrally presented face and the onset of a peripheral target, suggesting that attentional disengagement contributed to the delayed response in the direct gaze condition. The response delay to direct gaze was not found when the contrast polarity of eyes in the facial stimuli was reversed, reinforcing the importance of gaze perception in delayed disengagement from direct gaze.     

Face detection in 2‐ to 6‐month‐old infants is influenced by gaze direction and species

Humans detect faces efficiently from a young age. Face detection is critical for infants to identify and learn from relevant social stimuli in their environments. Faces with eye contact are an especially salient stimulus, and attention to the eyes in infancy is linked to the emergence of later sociality. Despite the importance of both of these early social skills—attending to faces and attending to the eyes—surprisingly little is known about how they interact. We used eye tracking to explore whether eye contact influences infants' face detection. Longitudinally, we examined 2‐, 4‐, and 6‐month‐olds' (N = 65) visual scanning of complex image arrays with human and animal faces varying in eye contact and head orientation. Across all ages, infants displayed superior detection of faces with eye contact; however, this effect varied as a function of species and head orientation. Infants were more attentive to human than animal faces and were more sensitive to eye and head orientation for human faces compared to animal faces. Unexpectedly, human faces with both averted heads and eyes received the most attention. This pattern may reflect the early emergence of gaze following—the ability to look where another individual looks—which begins to develop around this age. Infants may be especially interested in averted gaze faces, providing early scaffolding for joint attention. This study represents the first investigation to document infants' attention patterns to faces systematically varying in their attentional states. Together, these findings suggest that infants develop early, specialized functional conspecific face detection.     

Face processing is enhanced in the left and upper visual hemi-fields

We tested whether two known hemi-field asymmetries would affect visual search with face stimuli. Holistic processing of spatial configurations is better in the left hemi-field, reflecting a right hemisphere specialization, and object recognition is better in the upper visual field, reflecting stronger projections into the ventral stream. Faces tap into holistic processing and object recognition at the same time, which predicts better performance in the left and upper hemi-field, respectively. In the first experiment, participants had to detect a face with a gaze direction different from the remaining faces. Participants were faster to respond when targets were presented in the left and upper hemi-field. The same pattern of results was observed when only the eye region was presented. In the second experiment, we turned the faces upside-down, which eliminated the typical spatial configuration of faces. The left hemi-field advantage disappeared, showing that it is related to holistic processing of faces, whereas the upper hemi-field advantage related to object recognition persisted. Finally, we made the search task easier by asking observers to search for a face with open among closed eyes or vice versa. The easy search task eliminated the need for complex object recognition and, accordingly, the advantage of the upper visual field disappeared. Similarly, the left hemi-field advantage was attenuated. In sum, our findings show that both horizontal and vertical asymmetries affect the search for faces and can be selectively suppressed by changing characteristics of the stimuli.     

Talking heads or talking eyes? Effects of head orientation and sudden onset gaze cues on attention capture

The direction of gaze towards or away from an observer has immediate effects on attentional processing in the observer. Previous research indicates that faces with direct gaze are processed more efficiently than faces with averted gaze. We recently reported additional processing advantages for faces that suddenly adopt direct gaze (abruptly shift from averted to direct gaze) relative to static direct gaze (always in direct gaze), sudden averted gaze (abruptly shift from direct to averted gaze), and static averted gaze (always in averted gaze). Because changes in gaze orientation in previous study co-occurred with changes in head orientation, it was not clear if the effect is contingent on face or eye processing, or whether it requires both the eyes and the face to provide consistent information. The present study delineates the impact of head orientation, sudden onset motion cues, and gaze cues. Participants completed a target-detection task in which head position remained in a static averted or direct orientation while sudden onset motion and eye gaze cues were manipulated within each trial. The results indicate a sudden direct gaze advantage that resulted from the additive role of motion and gaze cues. Interestingly, the orientation of the face towards or away from the observer did not influence the sudden direct gaze effect, suggesting that eye gaze cues, not face orientation cues, are critical for the sudden direct gaze effect.     

Crossmodal spatial attention shift produced by centrally presented gaze cues1

Abstract: Despite previous failures to identify visual‐upon‐auditory spatial‐cuing effects, recent studies have demonstrated that the abrupt onset of a lateralized visual stimulus triggers a shift of spatial attention in response to auditory judgment. Nevertheless, whether a centrally presented visual stimulus orients auditory attention remained unclear. The present study investigated whether centrally presented gaze cues trigger a reflexive shift of attention in response to auditory judgment. Participants fixated on a schematic face in which the eyes looked left or right (the cue). A target sound was then presented to the left or right of the cue. Participants judged the direction of the target as quickly as possible. Even though participants were told that the gaze direction did not predict the direction of the target, the response time was significantly faster when the gaze was in the target direction than when it was in the non‐target direction. These findings provide initial evidence for visual‐upon‐auditory spatial‐cuing effects produced by centrally presented cues, suggesting that a reflexive crossmodal shift of attention does occur with a centrally presented visual stimulus.     

Visual search is not blind to emotion

A series of three visual search tasks revealed more efficient search for hostile than for peaceful faces among neutral face distractors. Given that this effect has been observed inconsistently in prior literature, meta-analytic methods were employed for evaluating data across three experiments in order to develop a more valid estimate of the potentially small effect size. Furthermore, in the present experiments, different emotional meanings were conditioned to identical faces across observers, thus eliminating confounds between the physical characteristics and the emotional valences of the face stimuli. On the basis of the present findings, we argue that the visual system is capable of determining a face's emotional valence before the face becomes the focus of attention, and that emotional valence can be used by the visual system to determine subsequent attention allocation. However, meta-analytic results indicate that emotional valence makes a relatively small contribution to search efficiency in the present search context.     

时间任务需求对无关情绪面孔注意捕获的影响

注意捕获是指与任务无关的刺激能够不自觉地吸引注意的现象。实验一采用视觉搜索任务,考察与主任务无关的情绪面孔的注意捕获水平及其机制,实验二进一步探究时间任务需求对无关情绪面孔注意捕获的影响。结果发现:与其他情绪面孔相比,愤怒的情绪面孔捕获了更多的注意,且受到整体情绪加工的影响;时间任务需求影响了目标刺激的注意选择,但愤怒优势效应不受到时间任务需求的影响,因此可能是一种较为自动化的加工过程。     

Increased gaze following for fearful faces. It depends on what you’re looking for!

An oculomotor visual search task was used to investigate how participants follow the gaze of a non-predictive and task irrelevant distractor gaze, and the way in which this gaze following is influenced by the emotional expression (fearful vs. happy) as well as participants' goal. Previous research has suggested that fearful emotions should result in stronger cueing effects than happy faces. Our results demonstrated that the degree to which the emotional expression influenced this gaze following varied as a function of the search target. When searching for a threatening target, participants were more likely to look in the direction of eye gaze on a fearful compared to a happy face. However, when searching for a pleasant target, this stronger cueing effect for fearful faces disappeared. Therefore, gaze following is influenced by contextual factors such as the emotional expression, as well as the participant's goal.