Face Perception in the Mind's Eye

Perceptual filling-in occurs when visual stimuli are recognized in impoverished viewing conditions. Whether missing information is filled-in during face perception and which stages might be involved in this process are still unresolved questions. Because an identity can be brought to mind by seeing eyes only, we hypothesized that missing information might be filled-in from a memory trace for the whole face identity. We presented participants with faces in phase 1 and later we presented eyes-only in phase 2. For some of these eyes in phase 2, the whole face had been presented in the previous phase, for others identical eyes had been presented. Event-related potentials (ERPs) revealed an N170 component that was more negative when eyes were preceded by a whole face in the previous phase compared to eyes preceded by identical eyes-only. A more positive-going late positive complex (LPC) was also found, suggesting enhanced retrieval of face memory representations when eyes were preceded by whole faces. Our results show that pre-existing representations of face identity can influence early stages of visual encoding, 170ms after stimulus onset. These effects may reflect top-down modulation by memory on visual recognition processes by filling-in the missing facial informatio

Differential impact of trait, social, and attachment anxiety on the stare-in-the-crowd effect

Eye gaze conveys crucial information for social interactions, with straight versus averted gaze triggering distinct emotional and cognitive processes. The “stare-in-the-crowd” effect exemplifies such differential visual processing of gaze direction, in more recent reports also in interaction with head orientation. Besides aiming at replicating the “stare-in-the-crowd” effect by means of an eye gaze by head orientation interaction, the present study intended to for the first time testing its susceptibility to inter-individual differences in trait, social, and attachment anxiety. Our findings reveal a significant relation between the “stare-in-the-crowd” effect and social and attachment, but not trait anxiety, and therefore provide preliminary cues for personality influences on visual processing of eye gaze and head orientation

Effect of perceived eye gaze on the N170 component – A systematic review

Direction of another person's eye gaze provides crucial information about their attention and intentions, which is essential for an effective social interaction. Event-related potential (ERP) measures offer precise temporal tracking of neural processes related to gaze perception. While the sensitivity of the ERP component N170 to face processing is principally agreed, the research on gaze direction effect on this component is thus far inconsistent. Here, we systematically reviewed literature on the sensitivity of N170 to gaze direction. We analysed if four factors, known to affect the face N170 (i.e., emotion, face orientation, task demand, and stimuli motion), were modulated by gaze direction. N170 sensitivity to gaze was reported the most in the studies that involved deviated faces, dynamic stimuli, and that used explicit tasks directly related to gaze or face processing. The present review provides a much-needed summary of the literature to date, highlighting the complexity of the effect of gaze direction on the N170 component, and the need of systematic studies investigating the combination of these factors.Swiss National Science Foundation; Fundação para a Ciência e Tecnologia - FCTinfo:eu-repo/semantics/publishedVersio

Amygdala activation for eye contact despite complete cortical blindness

Cortical blindness refers to the loss of vision that occurs after destruction of the primary visual cortex. Although there is no sensory cortex and hence no conscious vision, some cortically blind patients show amygdala activation in response to facial or bodily expressions of emotion. Here we investigated whether direction of gaze could also be processed in the absence of any functional visual cortex. A well-known patient with bilateral destruction of his visual cortex and subsequent cortical blindness was investigated in an fMRI paradigm during which blocks of faces were presented either with their gaze directed toward or away from the viewer. Increased right amygdala activation was found in response to directed compared with averted gaze. Activity in this region was further found to be functionally connected to a larger network associated with face and gaze processing. The present study demonstrates that, in human subjects, the amygdala response to eye contact does not require an intact primary visual cortex

Interaction between top-down and bottom-up attention in visual search

Notre déploiement attentionnel lors de tâche de recherche visuelle est ralenti par la présence d'un stimulus saillant non-pertinent pour la tâche. Ceci plaide pour une priorité des processus descendants sur les processus ascendants. La capture attentionnelle étant un processus précoce, nous avons décidé d'enquêter sur ce processus en utilisant l'électrophysiologie et plus précisément, un potentiel évoqué latéralisé appelé N2pc. Nous avons pu montré que la N2pc pour le distracteur était modulé par l'imprévisibilté de la cible. En outre, nous avons constaté une forte corrélation entre l'amplitude de la N2pc au distracteur et le niveau de distraction, mesurée par un questionnaire d'auto — évaluation (« Cognitive Failure Questionnaire »). De plus, nous avons démontré que lorsque la tâche ne necssite pas une identification claire d'une cible, une N2pc peut être remplacé par une positivité au distracteur. En résumé, ces données impliquent que la capture attentionelle est modulé par les processus descendant

Association between Attachment Anxiety and the Gaze Direction-Related N170

Attachment theory suggests that interindividual differences in attachment security versus insecurity (anxiety and avoidance) contribute to the ways in which people perceive social emotional signals, particularly from the human face. Among different facial features, eye gaze conveys crucial information for social interaction, with a straight gaze triggering different cognitive and emotional processes as compared to an averted gaze. It remains unknown, however, how interindividual differences in attachment associate with early face encoding in the context of a straight versus averted gaze. Using electroencephalography (EEG) and recording event-related potentials (ERPs), specifically the N170 component, the present study (N=50 healthy adults) measured how the characteristics of attachment anxiety and avoidance relate to the encoding of faces with respect to gaze direction and head orientation. Our findings reveal a significant relationship between gaze direction (irrespective of head orientation) and attachment anxiety on the interhemispheric (i.e., right) asymmetry of the N170 and thus provide evidence for an association between attachment anxiety and eye gaze processing during early visual face encoding

Task demands modulate effects of threatening faces on early perceptual encoding

The threat capture hypothesis states that threatening stimuli are automatically processed with higher priority than non-threatening stimuli, irrespective of the task. We evaluated the threat capture hypothesis with respect to the early perceptual stages of face processing. We focused on an electrophysiological marker of face processing (the lateralized N170) in response to neutral, happy, and angry facial expressions displayed in competition with a non-face stimulus (a house). We evaluated how effects of facial expression on the lateralized N170 were modulated by task demands. In one task, participants were required to identify the gender of the face, which made the face task-relevant and entailed structural encoding of the face stimulus. In another task, participants identified the location of a missing pixel in the fixation cross, which made the face task-irrelevant and placed it outside the focus of attention. When faces were relevant, the lateralized N170 to angry faces was enhanced compared to happy and neutral faces. When faces were irrelevant, facial expression had no effect. These results reveal the critical role of task demands on the preference for threatening faces, indicating that top-down, voluntary processing modulates the prioritization of threat