Differences in the perception of direct gaze between the externally and internally rotated eye

The perception of direct gaze provides multiple benefits for the observer. Previous studies have investigated how the information from both eyes is used to estimate gaze direction, showing that the perception of gaze direction differs when only the externally rotated eye versus only the internally rotated eye is visible. We examined the width and center of the area of direct gaze by presenting the observers with either the externally or internally rotated eye, or both eyes with the task to judge whether a computer avatar is looking at them. Two experiments yield evidence for a wider area of direct gaze for the externally rotated eye (around 6°) than for the internally rotated eye (around 4°). The area of direct gaze for both eyes was found to be the same as for the internally rotated eye, but smaller than for the externally rotated eye. When both eyes were present, our results indicate that the perception of direct gaze is more likely to follow the internally rotated eye. The discussion substantiates a new generalization that observers base their judgments on the more rotated eye, which can differ due to angle kappa and vergence, in our study it is the internally rotated eye.

'I am afraid you will see the stain on my soul': Direct gaze neural processing in individuals with PTSD after moral injury recall

Direct eye contact is essential to understanding others' thoughts and feelings in social interactions. However, those with post-traumatic stress disorder (PTSD) and exposure to moral injury (MI) may exhibit altered theory-of-mind (ToM)/mentalizing processes and experience shame which precludes one's capacity for direct eye contact. We investigated blood oxygenation level-dependent (BOLD) responses associated with direct vs averted gaze using a virtual reality paradigm in individuals with PTSD (n = 28) relative to healthy controls (n = 18) following recall of a MI vs a neutral memory. Associations between BOLD responses and clinical symptomatology were also assessed. After MI recall, individuals with PTSD showed greater activation in the right temporoparietal junction as compared to controls (T = 4.83; pFDR < 0.001; k = 237) during direct gaze. No significant activation occurred during direct gaze after neutral memory recall. Further, a significant positive correlation was found between feelings of distress and right medial superior frontal gyrus activation in individuals with PTSD (T = 5.03; pFDR = 0.049; k = 123). These findings suggest that direct gaze after MI recall prompts compensatory ToM/mentalizing processing. Implications for future interventions aimed at mitigating the effects of PTSD on social functioning are discussed.

Infant responses to direct gaze and associations to autism: A live eye-tracking study

LAY ABSTRACT

When other people look directly towards us, we often respond by looking back at them, and such direct-gaze responses are important for establishing eye contact. Atypical eye contact is common in autism, but how and when this aspect of autism develops is not well understood. Here, we studied whether how much and how quickly infants respond to others' direct gaze is associated with autism in toddlerhood. We did this by measuring direct-gaze responses in a playful social interaction using live eye tracking. The study included 169 infants, of whom 129 had an elevated likelihood of developing autism due to having a first-degree family member with the condition, and 40 with typical likelihood of autism. In the elevated likelihood group, 35 were diagnosed with autism spectrum disorder at 3 years of age, and 94 were not. The results showed that infants in all three groups tended to increase their looking towards the adult's face after the adult looked directly at them. However, neither how much nor how quickly the infants responded to direct gaze by looking back at the adult reliably differentiated the infants with or without subsequent autism. While infants in the elevated likelihood of autism and subsequent diagnosis group tended to look away quicker from faces with direct gaze than infants in the typical likelihood group, this measure did not differentiate between the two elevated likelihood groups. We interpret the results as supporting the view that atypical direct-gaze responses are not early markers of autism.

The effects of the presence of a face and direct eye gaze on voice identity learning

We rarely become familiar with the voice of another person in isolation but usually also have access to visual identity information, thus learning to recognize their voice and face in parallel. There are conflicting findings as to whether learning to recognize voices in audiovisual vs audio-only settings is advantageous or detrimental to learning. One prominent finding shows that the presence of a face overshadows the voice, hindering voice identity learning by capturing listeners' attention (Face Overshadowing Effect; FOE). In the current study, we tested the proposal that the effect of audiovisual training on voice identity learning is driven by attentional processes. Participants learned to recognize voices through either audio-only training (Audio-Only) or through three versions of audiovisual training, where a face was presented alongside the voices. During audiovisual training, the faces were either looking at the camera (Direct Gaze), were looking to the side (Averted Gaze) or had closed eyes (No Gaze). We found a graded effect of gaze on voice identity learning: Voice identity recognition was most accurate after audio-only training and least accurate after audiovisual training including direct gaze, constituting a FOE. While effect sizes were overall small, the magnitude of FOE was halved for the Averted and No Gaze conditions. With direct gaze being associated with increased attention capture compared to averted or no gaze, the current findings suggest that incidental attention capture at least partially underpins the FOE. We discuss these findings in light of visual dominance effects and the relative informativeness of faces vs voices for identity perception.

How vergence influences the perception of being looked at

Perceiving other people's direct gaze is important for many areas of everyday activity. For horizontal and vertical eye movements, the area of being looked at, known as the cone of gaze, has been well explored. Previous research has shown a range of eye rotations (up to eccentricities of 4°-9°) that people accept as direct gaze. Vergence is an important cue for perceiving the depth of fixation. This study examines the range of vergence angles that support the perception of being looked at. In two experiments, observers adjusted the degree of vergence of the lookers' eyes until they felt just (not) looked at. The first experiment also asked to adjust the point of being exactly looked at, which was 0° (parallel eyes). The thresholds of being just (not) looked at were around 4.5° of convergence and 2.5° divergence, which results in a depth of 7° of vergence. This depth was replicated in Experiment 2, while the thresholds of convergence (3.5°) and divergence (3.5°) slightly differ from Experiment 1. The results indicate a consistent area of vergences being accepted as direct gaze, yielding first-time evidence for a third dimension-the depth dimension-of direct gaze.

Eccentric Gaze as a Possible Cause of "Zoom Fatigue"

BACKGROUND

The Covid-19 pandemic has led to a marked increase in the use of videoconferencing for social interaction. Many people report discomfort and disaffection with this modality, which has been labeled "Zoom Fatigue." Common videoconferencing hardware setups necessitate that if a user looks at the image of the person with whom they are in videoconference, they will not be looking directly at the camera and will appear to not be making direct eye contact. This study determined the minimum threshold of eccentric gaze in a videoconferencing setup above which subjects are perceived as not making direct eye contact by the majority of untrained observers.

METHODS

Image captures were made of four subjects successively fixating at small increments eccentric to a video camera, both vertically and horizontally ranging from 0.9 degrees to 19 degrees of eccentricity. The images were embedded in separate Powerpoint files for each subject. Each file was assessed by seven graders who indicated whether or not they felt the subject was looking directly at them in each slide.

RESULTS

The threshold for which 75% of the graders could detect that the subject was not looking at them ranged from only 2.7 degrees for horizontal eccentricity to 5.4 degrees for vertical eccentricity.

CONCLUSION

The hardware setups commonly used for videoconferencing result in persistent eccentric gaze of the participating individuals if they look at the image of the other participants. In theory, this could be a contributing cause of Zoom Fatigue.

The Cone of Direct Gaze: A Stable Trait

Direct eye gaze is a potent stimulus in social interactions and is often associated with interest and approach orientation. Yet, there is remarkable variability in the range of gaze lines that people accept as being direct. A measure that is frequently used to quantify the range of gaze angles within which an observer assumes mutual gaze is the cone of direct gaze (CoDG). While individual differences in CoDG have often been examined, studies that systematically investigate the stability of an observers' CoDG over time are scarce. In two experiments, we measured the CoDG using an established paradigm and repeated the measurement after 5 min and/or after 1 week. We found high inter-individual variation, but high agreement within participants (ICCs between 0.649 and 0.855). We conclude that the CoDG can be seen as a rather stable measure, much like a personality trait.

Gazing Without Eyes: A "Stare-in-the-Crowd" Effect Induced by Simple Geometric Shapes

Of the many effects that eye contact has, perhaps the most powerful is the stare-in-the-crowd effect, wherein faces are detected more readily when they look directly toward you. This is commonly attributed to others' eyes being especially salient visual stimuli, but here we ask whether stares-in-the-crowd might arise instead from a deeper property that the eyes (but not only the eyes) signify: the direction of others' attention and intentions. In fact, even simple geometric shapes can be seen as intentional, as when numerous randomly scattered cones are all consistently pointing at you. Accordingly, we show here that cones directed at the observer are detected faster (in fields of averted cones) than are cones averted away from the observer (in fields of directed cones). These results suggest that perceived intentionality itself captures attention-and that even in the absence of eyes, others' directed attention stands out in a crowd.

Psychophysiological responses to eye contact in a live interaction and in video call

Another person's gaze directed to oneself elicits autonomic arousal and facial reactions indicating positive affect in its observer. These effects have only been found to occur with mutual, live eye contact and not in response to direct gaze pictures or when the observer believes that the live person cannot see them. The question remains whether the physical presence of the other person is necessary for these effects. We measured psychophysiological responses to another person's direct versus averted gaze in three conditions: live interaction, bidirectional video call, and watching a mere video. Autonomic arousal was measured with skin conductance responses and facial reactions with facial electromyography. In the live and video call conditions, but not in the mere video condition, direct gaze increased autonomic arousal in comparison to averted gaze. In all three conditions, however, direct gaze elicited positive affective facial reactions. Therefore, an experience of being seen is essential for the autonomic reactions but not for the facial responses that are elicited by another person's direct gaze. Most importantly, the results suggest that the physical presence or proximity of the other person is not necessary for these psychophysiological responses to eye contact.

A look at actions: direct gaze modulates functional connectivity of the right TPJ with an action control network

Social signals such as eye contact and motor actions are essential elements of social interactions. However, our knowledge about the interplay of gaze signals and the control of actions remains limited. In a group of 30 healthy participants, we investigated the effect of gaze (direct gaze vs averted) on behavioral and neural measures of action control as assessed by a spatial congruency task (spatially congruent vs incongruent button presses in response to gaze shifts). Behavioral results demonstrate that inter-individual differences in condition-specific incongruency costs were associated with autistic traits. While there was no interaction effect of gaze and action control on brain activation, in a context of incongruent responses to direct gaze shifts, a psychophysiological interaction analysis showed increased functional coupling between the right temporoparietal junction, a key region in gaze processing, and the inferior frontal gyri, which have been related to both social cognition and motor inhibition. Conversely, incongruency costs to averted gaze were reflected in increased connectivity with action control areas implicated in top-down attentional processes. Our findings indicate that direct gaze perception inter-individually modulates motor actions and enforces the functional integration of gaze-related social cognition and action control processes, thereby connecting functional elements of social interactions.

The influence of top-down modulation on the processing of direct gaze

Gaze or eye contact is one of the most important nonverbal social cues, which is fundamental to human social interactions. To achieve real time and dynamic face-to-face communication, our brain needs to process another person's gaze direction rapidly and without explicit instruction. In order to explain the fast and spontaneous processing of direct gaze, the fast-track modulator model was proposed. Here, we review recent developments in gaze processing research in the last decade to extend the fast-track modulator model. In particular, we propose that task demand or top-down modulation could play a more crucial role at gaze processing than formerly assumed. We suggest that under different task demands, top-down modulation can facilitate or interfere with the direct gaze effects for early visual processing. The proposed modification of the model extends the role of task demand and its implication on the direct gaze effect, as well as the need to better control for top-down processing in order to better disentangle the role of top-down and bottom-up processing on the direct gaze effect. This article is categorized under: Cognitive Biology > Evolutionary Roots of Cognition Psychology > Perception and Psychophysics Neuroscience > Cognition.

Implicit Perceptions of Closeness From the Direct Eye Gaze

Eye gaze plays an important role during social interaction. Specifically, different eye gaze directions may send different functional messages to the observers, who have the capacity to automatically interpret these signals. In the present study, we used the implicit association test (IAT) to investigate whether direct eye gaze sends a functional, automatically perceived signal about non-target interpersonal closeness. Results suggest that the direct gaze strongly signals close relationship, and this association cannot be accounted for by positive valence. The findings suggest that the direct gaze may function to uniquely communicate a generalized closeness without orientation. Discussion focuses on the implications of these findings for social functions of direct gaze during interpersonal interaction and the automatic nature of such associations.

Direct Gaze Partially Overcomes Hemispatial Neglect and Captures Spatial Attention

Direct gaze has been shown to be a particularly important social cue, being preferentially processed even when unconsciously perceived. Results from several visual search tasks further suggest that direct gaze modulates attention, showing a faster orientation to faces perceived as looking toward us. The present study aimed to analyze putative modulation of spatial attention by eye gaze direction in patients with unilateral neglect. Eight right hemisphere stroke patients with neglect performed a target cancelation paradigm. Patients were instructed to cross all open-eyed pictures amidst closed eyed distractors. Target images were either in direct or averted gaze. Participants performed significantly better when observing targets with direct gaze supporting the hypothesis that this gaze direction captures attention. These findings further suggest that perception of direct gaze is able to diminish the visuospatial impairment seen in neglect patients.

Social decisions affect neural activity to perceived dynamic gaze

Gaze direction, a cue of both social and spatial attention, is known to modulate early neural responses to faces e.g. N170. However, findings in the literature have been inconsistent, likely reflecting differences in stimulus characteristics and task requirements. Here, we investigated the effect of task on neural responses to dynamic gaze changes: away and toward transitions (resulting or not in eye contact). Subjects performed, in random order, social (away/toward them) and non-social (left/right) judgment tasks on these stimuli. Overall, in the non-social task, results showed a larger N170 to gaze aversion than gaze motion toward the observer. In the social task, however, this difference was no longer present in the right hemisphere, likely reflecting an enhanced N170 to gaze motion toward the observer. Our behavioral and event-related potential data indicate that performing social judgments enhances saliency of gaze motion toward the observer, even those that did not result in gaze contact. These data and that of previous studies suggest two modes of processing visual information: a 'default mode' that may focus on spatial information; a 'socially aware mode' that might be activated when subjects are required to make social judgments. The exact mechanism that allows switching from one mode to the other remains to be clarified.

Propensity to imitate in autism is not modulated by the model's gaze direction: an eye-tracking study

Individuals with Autism Spectrum Disorder (ASD) show a diminished propensity to imitate others' actions, as well as a diminished sensitivity and responsivity to others' communicative cues, such as a direct gaze. However, it is not known whether failure to appreciate the communicative value of a direct gaze is associated with imitation abnormalities in this population. In this eye-tracking study, we investigated how 25 preschoolers with ASD, compared with 25 developmental and chronological age-matched children, imitate actions that are associated with a model's direct gaze versus averted gaze. We found that the model's direct gaze immediately prior to the demonstration increased the attention to the model and the propensity to imitate the demonstrated action in children without ASD. In contrast, preschoolers with ASD showed a similar propensity to look at the model's face and to imitate the demonstrated actions across the direct gaze and the averted gaze conditions. These data indicate that atypical imitation in ASD might be linked to abnormal processing of the model's communicative signals (such as a direct gaze) that modulate imitative behaviours in individuals without ASD. Autism Res 2014, 7: 392-399. © 2014 International Society for Autism Research, Wiley Periodicals, Inc.

Brain mechanisms for processing direct and averted gaze in individuals with autism

Prior studies have indicated brain abnormalities underlying social processing in autism, but no fMRI study has specifically addressed the differential processing of direct and averted gaze, a critical social cue. Fifteen adolescents and adults with autism and 14 typically developing comparison participants viewed dynamic virtual-reality videos depicting a simple but realistic social scenario, in which an approaching male figure maintained either direct or averted gaze. Significant group by condition interactions reflecting differential responses to direct versus averted gaze in people with autism relative to typically developing individuals were identified in the right temporoparietal junction, right anterior insula, left lateral occipital cortex, and left dorsolateral prefrontal cortex. Our results provide initial evidence regarding brain mechanisms underlying the processing of gaze direction during simple social encounters, providing new insight into the social deficits in individuals with autism.