How wide is the cone of direct gaze?

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.

Are the directions of both eyes integrated before or after the perception of direct gaze? Evidence from simulated mild strabismus

The cone of gaze is a looker's range of gaze directions that is accepted as direct by an observer. The present research asks how the condition of mild strabismus, that is, when the two eyes point in slightly different directions, influences the cone of gaze. Normally, both eyes are rotated in a coordinated manner such that both eyes are directed to the same fixation point. With strabismus, there are two fixation points, and, therefore, two directions into which the two eyes point. This raises the question of the direction and the shape (i.e., width) of the gaze cone. Two experiments are conducted with simulated mild strabismus. Three conditions are tested, the two strabismic conditions of esotropia, and exotropia and one orthotropic (nonstrabismic) condition. Results show that the direction of the gaze cone is roughly the average of the directions of the two eyes. Furthermore, the width of the gaze cone is not affected by simulated strabismus and is thus the same for the strabismic and the orthotropic conditions. The results imply a model where at first the direction of gaze based on both eyes is perceived, and where the gaze cone is implied on the basis of the combined gaze direction.

Autistic traits modulate the influence of face masks on gaze perception

Detecting when others are looking at us is a crucial social skill. Accordingly, a range of gaze angles is perceived as self-directed; this is termed the "cone of direct gaze" (CoDG). Multiple cues, such as nose and head orientation, are integrated during gaze perception. Thus, occluding the lower portion of the face, such as with face masks during the COVID-19 pandemic, may influence how gaze is perceived. Individual differences in the prioritisation of eye-region and non-eye-region cues may modulate the influence of face masks on gaze perception. Autistic individuals, who may be more reliant on non-eye-region directional cues during gaze perception, might be differentially affected by face masks. In the present study, we compared the CoDG when viewing masked and unmasked faces (N = 157) and measured self-reported autistic traits. The CoDG was wider for masked compared to unmasked faces, suggesting that reduced reliability of lower face cues increases the range of gaze angles perceived as self-directed. Additionally, autistic traits positively predicted the magnitude of CoDG difference between masked and unmasked faces. This study provides crucial insights into the effect of face masks on gaze perception, and how they may affect autistic individuals to a greater extent.

Perception of direct gaze in a video-conference setting: the effects of position and size

A common problem in video conferences is gaze direction. In face-to-face communication, it is common that speaker and listener intermittently look at each other. In a video-conference setting, where multiple participants are on the screen, things are complicated and not necessarily optimal. If the listener feels looked at when the speaker looks into the camera, how tolerant is the listener for slight deviations? And does this depend on the position of the speaker’s tile on the screen, or the size of the tile? In a first experiment, participants from a student population judged whether they are looked at, while vertical gaze direction of the looker was varied. Furthermore, the position of the tile on the screen varied. The results showed that a slightly upward directed gaze was optimal for the direct gaze judgment, with a width of ± 4 degrees. Optimal gaze direction was somewhat higher for tiles at the bottom of the screen. A second experiment tested the effect of size on the perception of horizontal gaze directions. Size was found to increase the gaze cone. The paper concludes with some recommendations for a setup of video conference systems, optimized for perceived gaze contact.

Face masks have a limited effect on the feeling of being looked at

Introduction

Wearing face masks has been promoted as an effective measure to reduce the spread of COVID-19. Because face masks cover a major part of the face, they have detrimental effects on various aspects of social cognition. Yet, a highly important feature of the face is not occluded by face masks: the eyes. The eyes play an important role in social interactions: knowing where another person is looking is of central importance when interacting with others. Recent research has reported an attentional shift toward the eye region as a consequence of the widespread exposure to face masks. However, no study has yet investigated the influence of face masks on the perception of eye gaze direction. Here we investigated whether face masks have an effect on the feeling of being looked at. Assuming an attentional shift toward the eyes, we might expect more accurate gaze perception in faces wearing face masks.

Methods

Sixty-five participants decided for a series of realistic avatar faces whether each face was making eye contact or not. Half of the faces wore face masks, the other half did not. For each participant and separately for each condition (mask vs. no mask), we calculated the cone of direct gaze (CoDG), a commonly used measure to quantify the range of gaze angles within which an observer assumes mutual gaze.

Results

Contrary to our expectations, results show that mutual gaze is not recognized more accurately in masked faces. Rather, the CoDG was, on average, slightly wider for faces wearing masks compared to faces without masks.

Discussion

Notwithstanding the relatively small effect of face mask, these findings potentially have implications on our social interactions. If we inadvertently feel looked at by an onlooker, we may react inappropriately by reciprocating the alleged approach orientation.

Perception of eye contact, self-referential thinking and age

Increased thinking about one's self has been proposed to widen the gaze cone, that is, the range of gaze deviations that an observer judges as looking directly at them (eye contact). This study investigated the effects of a self-referential thinking manipulation and demographic factors on the gaze cone. In a preregistered experiment (N = 200), the self-referential thinking manipulation, as compared to a control manipulation, did not influence the gaze cone, or the use of first-person pronouns in a manipulation check measuring self-referential processing. This may indicate a failure of the manipulation and participants' lack of effort. However, participants' age was significantly correlated with both measures: older people had wider gaze cones and used more self-referring pronouns. A second experiment (N = 300) further examined the effect of the manipulation and demographic factors on self-referential processing, and the results were replicated. These findings may reflect age-related self-reference and positivity effects.

Explicit and implicit mentalization of patients with first-episode schizophrenia: a study of self-referential gaze perception with eye movement analysis using hidden Markov models

Mentalizing impairment is one of the core features of schizophrenia, and bias judgement of others' gaze as self-directing is common to schizophrenia patients. In this case-control study, 30 patients with first-episode schizophrenia (FES) and 30 matched healthy controls were assigned gaze perception tasks with variable stimulus presentation times (300 ms and no time limit) to determine the presence of self-referential gaze perception (SRGP) bias. The eye movement pattern during the task were tracked and data were analysed using hidden Markov models (HMMs). The SRGP involves reporting of others' gaze intent and was used as a measurement of explicit mentalizing process. Eye movement measurement represents automated visual attention pattern and was considered as a measurement of implicit mentalizing process. The patients with FES had significantly more SRGP bias than the controls in the 300 ms condition but not in the no-time-limit condition. Social cognitive function was related to SRGP bias in the patient group. Two distinct eye movement patterns were identified: eye-focused and nose-focused. Significant group differences in eye movement patterns in the 300 ms condition were found with more controls had eye-focused pattern. Social anxiety symptoms were related to the nose-focused pattern, positive psychotic symptoms were related to the eye-focused pattern, and depressive symptoms were related to less consistent eye movement patterns. No significant relationship was found between SRGP bias and eye movement patterns. The dissociation between explicit and implicit mentalizing processes with different cognitive and symptom dimensions associated with the two processes suggests the presence of different mechanisms.

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.

Looking Into Mona Lisa’s Smiling Eyes: Allusion to an Illusion

We present results from two experiments aimed at studying the direction of Mona Lisa’s gaze and its affective expression. In experiment 1 we studied the effect of retinal image size on the perception of her gaze by manipulating observation distances of a high-quality print of the painting. Participants (N = 30) were asked to answer a simple question (is the person portrayed looking at you?) from six different distances ranging from 55 to 755 cm. One group of participants started evaluations from 55 cm; the other group did the opposite. Results show an effect of distance on the perception of Mona Lisa’s gaze as staring at the observer: from the furthest distances, the impression of a staring Mona Lisa is robust; from the nearest distances, such impression becomes ambiguous. Experiment 2 presents data concerning the direction of Mona Lisa’s gaze and whether this appears to be smiling, derived from an experiment aimed at studying the impression of gaze (direction and emotional content) in portraits (paintings and photographs). Only data concerning Mona Lisa are reported. Participants (N = 41) were randomly assigned to one of two groups: on a LCD screen, one group saw the entire head, and the other group saw only a section reproducing Mona Lisa’s eyes. Experimental sessions were two: in session 1 participants had to decide whether the image (whole-head or eyes only) was looking at them; in session 2 participants had to decide whether the head (or the eyes) was smiling. RTs from the two groups of participants were not statistically significant. Results for session 1 confirm experiment 1’s general findings. Results for session 2 clearly show that Mona Lisa is not only smiling with her face, but also with her eyes. Results are discussed in relation to the literature on Mona Lisa’s gaze and smile.

Is there a 'zone of eye contact' within the borders of the face?

Eye contact is a salient feature of everyday interactions, yet it is not obvious what the physical conditions are under which we feel that we have eye contact with another person. Here we measure the range of locations that gaze can fall on a person's face to elicit a sense of eye contact. Participants made judgements about eye contact while viewing rendered images of faces with finely-varying gaze direction at a close interpersonal distance (50 cm). The 'zone of eye contact' tends to peak between the two eyes and is often surprisingly narrower than the observer's actual eye region. Indeed, the zone tends to extend further across the face in height than in width. This shares an interesting parallel with the 'cyclopean eye' of visual perspective - our sense of looking out from a single point in space despite the physical separation of our two eyes. The distribution of eye-contact strength across the face can be modelled at the individual-subject level as a 2D Gaussian function. Perception of eye contact is more precise than the sense of having one's face looked at, which captures a wider range of gaze locations in both the horizontal and vertical dimensions, at least at the close viewing distance used in the present study. These features of eye-contact perception are very similar cross-culturally, tested here in Australian and Japanese university students. However, the shape and position of the zone of eye contact does vary depending on recent sensory experience: adaptation to faces with averted gaze causes a pronounced shift and widening of the zone across the face, and judgements about eye contact also show a positive serial dependence. Together, these results provide insight into the conditions under which eye contact is felt, with respect to face morphology, culture, and sensory context.

Examining Gaze Cone Shape and Size

Another person's looking behavior is used by observers to judge gaze direction and fixation points. An important task in this context is the judgement of direct gaze, that is, the perception of being looked at. The cone of gaze can be defined as the range of fixation points that support direct gaze. The cone concept implies that this range lawfully increases with distance, but that the cone angle is constant. The present experiment tested the concept with a larger number and a more extended range of distances than previously done, and took care of possible directional errors. The gaze cone was found to be roughly linear, and stable between 1.6 m and 7.9 m - an almost perfect cone. The mean cone size subtended 5.2° in diameter when averaged over ascending and descending series. Measures differed, however, in ascending and descending series, consistent with a conservative bias. Also, the variability of judgements increased slightly with distance. Results are discussed considering whether cone size is actually smaller than often reported in the literature.

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.

Self-referential gaze perception of patients with schizophrenia and its relationship with symptomatology and cognitive functions

Self-referential gaze perception (SRGP)-the perception that others' gaze is towards oneself-is a core experience in patients with schizophrenia, and may be related to common delusional themes such as delusions of reference. Studies exploring SRGP bias in schizophrenia are limited and results have been inconsistent, particularly regarding its relationship with symptomatology and cognition. Seventy-five patients with schizophrenia-spectrum disorders (25 with high level of reference delusion, 25 with low reference delusion and 25 in clinical remission) and 25 matched healthy controls were compared in a gaze perception task to judge whether averted gaze with varied ambiguity was directed at them. All subjects were assessed with delusion and reference ideations and cognitive functions. Psychotic symptoms were assessed in patients. Gaze perception analysis adopted both behavioural and psychophysical approaches. Group differences and predictors of SRGP in ambiguous and unambiguous conditions were investigated. Both groups of symptomatic patients displayed higher ambiguous SRGP rate, and the group with high reference delusions showed more unambiguous SRGP bias. Cognitive functions were negatively associated with SRGP rate while positive and negative symptoms were positively associated. Cognitive function was the only significant predictor for ambiguous-SRGP rate. Patients with psychotic symptoms have hypermentalization of gaze perception as towards oneself, whereas patients with delusions of reference have more profound bias in gaze perception. General cognition is implicated in SRGP rate. Future studies could investigate interventions with targeted psychopathological profiles by improving non-social cognitive functions to test the hypothesis that cognitive functioning is related to SRGP bias and delusional beliefs.

Face Pareidolia Recruits Mechanisms for Detecting Human Social Attention

Face pareidolia is the phenomenon of seeing facelike structures in everyday objects. Here, we tested the hypothesis that face pareidolia, rather than being limited to a cognitive or mnemonic association, reflects the activation of visual mechanisms that typically process human faces. We focused on sensory cues to social attention, which engage cell populations in temporal cortex that are susceptible to habituation effects. Repeated exposure to “pareidolia faces” that appear to have a specific direction of attention causes a systematic bias in the perception of where human faces are looking, indicating that overlapping sensory mechanisms are recruited when we view human faces and when we experience face pareidolia. These cross-adaptation effects are significantly reduced when pareidolia is abolished by removing facelike features from the objects. These results indicate that face pareidolia is essentially a perceptual phenomenon, occurring when sensory input is processed by visual mechanisms that have evolved to extract specific social content from human faces.