The Mona Lisa effect: neural correlates of centered and off-centered gaze

Neural circuit disruptions of eye gaze processing in autism spectrum disorder and schizophrenia: An activation likelihood estimation meta-analysis

BACKGROUND

Impairment in social cognition, particularly eye gaze processing, is a shared feature common to autism spectrum disorder (ASD) and schizophrenia. However, it is unclear if a convergent neural mechanism also underlies gaze dysfunction in these conditions. The present study examined whether this shared eye gaze phenotype is reflected in a profile of convergent neurobiological dysfunction in ASD and schizophrenia.

METHODS

Activation likelihood estimation (ALE) meta-analyses were conducted on peak voxel coordinates across the whole brain to identify spatial convergence. Functional coactivation with regions emerging as significant was assessed using meta-analytic connectivity modeling. Functional decoding was also conducted.

RESULTS

Fifty-six experiments (n = 30 with schizophrenia and n = 26 with ASD) from 36 articles met inclusion criteria, which comprised 354 participants with ASD, 275 with schizophrenia and 613 healthy controls (1242 participants in total). In ASD, aberrant activation was found in the left amygdala relative to unaffected controls during gaze processing. In schizophrenia, aberrant activation was found in the right inferior frontal gyrus and supplementary motor area. Across ASD and schizophrenia, aberrant activation was found in the right inferior frontal gyrus and right fusiform gyrus during gaze processing. Functional decoding mapped the left amygdala to domains related to emotion processing and cognition, the right inferior frontal gyrus to cognition and perception, and the right fusiform gyrus to visual perception, spatial cognition, and emotion perception. These regions also showed meta-analytic connectivity to frontoparietal and frontotemporal circuitry.

CONCLUSION

Alterations in frontoparietal and frontotemporal circuitry emerged as neural markers of gaze impairments in ASD and schizophrenia. These findings have implications for advancing transdiagnostic biomarkers to inform targeted treatments for ASD and schizophrenia.

Aberrant Effective Connectivity During Eye Gaze Processing Is Linked to Social Functioning and Symptoms in Schizophrenia

BACKGROUND

Patients with schizophrenia show abnormal gaze processing, which is associated with social dysfunction. These abnormalities are related to aberrant connectivity among brain regions that are associated with visual processing, social cognition, and cognitive control. In this study, we investigated 1) how effective connectivity during gaze processing is disrupted in schizophrenia and 2) how this may contribute to social dysfunction and clinical symptoms.

METHODS

Thirty-nine patients with schizophrenia/schizoaffective disorder (SZ) and 33 healthy control participants completed an eye gaze processing task during functional magnetic resonance imaging. Participants viewed faces with different gaze angles and performed explicit and implicit gaze processing. Four brain regions-the secondary visual cortex, posterior superior temporal sulcus, inferior parietal lobule, and posterior medial frontal cortex-were identified as nodes for dynamic causal modeling analysis.

RESULTS

Both the SZ and healthy control groups showed similar model structures for general gaze processing. Explicit gaze discrimination led to changes in effective connectivity, including stronger excitatory, bottom-up connections from the secondary visual cortex to the posterior superior temporal sulcus and inferior parietal lobule and inhibitory, top-down connections from the posterior medial frontal cortex to the secondary visual cortex. Group differences in top-down modulation from the posterior medial frontal cortex to the posterior superior temporal sulcus and inferior parietal lobule were noted, such that these inhibitory connections were attenuated in the healthy control group but further strengthened in the SZ group. Connectivity was associated with social dysfunction and symptom severity.

CONCLUSIONS

The SZ group showed notably stronger top-down inhibition during explicit gaze discrimination, which was associated with more social dysfunction but less severe symptoms among patients. These findings help pinpoint neural mechanisms of aberrant gaze processing and may serve as future targets for interventions that combine neuromodulation with social cognitive training.

Neurobehavioral indices of gaze perception are associated with social cognition across schizophrenia patients and healthy controls

BACKGROUND

Gaze perception is a basic building block of social cognition, which is impaired in schizophrenia (SZ) and contributes to functional outcomes. Few studies, however, have investigated neural underpinnings of gaze perception and their relation to social cognition. We address this gap.

METHOD

We recruited 77 SZ patients and 71 healthy controls, who completed various social-cognition tasks. During functional magnetic resonance imaging, participants (62 SZ, 54 controls) completed a gaze-perception task, where they judged whether faces with varying gaze angles were self-directed or averted; as a control condition, participants identified stimulus gender. Activation estimates were extracted based on (a) task versus baseline, (b) gaze-perception versus gender-identification, (c) parametric modulation by perception of stimuli as self-directed versus averted, and (d) parametric modulation by stimulus gaze angle. We used latent variable analysis to test associations among diagnostic group, brain activation, gaze perception, and social cognition.

RESULTS

Preferential activation to gaze perception was observed throughout dorsomedial prefrontal cortex, superior temporal sulcus, and insula. Activation was modulated by stimulus gaze angle and perception of stimuli as self-directed versus averted. More precise gaze perception and higher task-related activation were associated with better social cognition. Patients with SZ showed hyperactivation within left pre-/postcentral gyrus, which was associated with more precise gaze perception and fewer symptoms and thus may be a compensatory mechanism.

CONCLUSIONS

Neural and behavioral indices of gaze perception were related to social cognition, across patients and controls. This suggests gaze perception is an important perceptual building block for more complex social cognition. Results are discussed in the context of dimensional psychopathology and clinical heterogeneity. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

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.

PLEA

An approach to the design of learning environments where a social robot plays a role of a teacher is discussed in this study. Built-in robot functionalities provide a degree of situational embodiment, self-explainability, and context-driven interaction. The concept of embodiment enables immersion of the teacher into distant 3D environments. In that way the level of mutual understanding between participants is increased compared to a 2D world. Moreover, the tools that accompany the interaction empower augmentation by revealing the additional information present in gestures, facial expressions, or gaze direction. We use three distinct sources fused in a multimodal approach (face emotion recognition, level of loudness, and body movement intensity). The change in one modality can change the overall system reasoning. The teacher can benefit from this information by adapting a presentation style and achieve a better rapport with students. The theoretical basis is provided by studies of human communication in psycholinguistics and social psychology. Usability evaluation is based on the Wizard of Oz approach, allowing a teacher to interact with students through an interface. The conducted experiments show encouraging responses. Future studies will show in what way and to what extent a cognitive robot can be truly effective in technology-enhanced learning.

Intranasal oxytocin enhances the perception of ambiguous averted gaze in women but not in men

BACKGROUND

Perceiving accurately that others are looking away from us (averted gaze) is as important, for social interactions, as perceiving that others are looking at us (direct gaze). However, previous studies have revealed that when the deflection angle of averted gaze is small, individuals tend to falsely perceive it as direct gaze. Oxytocin (OXT) has been shown to increase orientation to the eye region. Therefore, a critical question is whether and how OXT would facilitate the perception of ambiguous averted gaze.

OBJECTIVES

The present study aimed to measure the effects of OXT on the performance of males and females in distinguishing ambiguous averted gaze from direct gaze of different emotional faces.

METHODS

In a double-blind placebo-controlled crossover experiment, 48 participants were presented successively two emotional faces with direct gaze (defined as 0, indicating the center of the eye) or averted gaze (defined as ±4, indicating the corner of the eye; +4 means that the iris moves 4 steps to the right; and -4 means that the iris moves 4 steps to the left) following intranasal oxytocin or placebo treatment and asked to make judgments on whether or not the two faces were the same in terms of identity. The interference effect of gaze direction was calculated by subtracting the mean accuracy and reaction time in the congruent gaze condition from those in the incongruent gaze condition. The logic of the measurement was if intranasal OXT would facilitate the detection of ambiguous averted gaze, we would observe a larger interference effect in the gaze incongruent condition compared with the gaze congruent condition, leading to longer RT or/and lower accuracy for identification judgment in the gaze incongruent condition.

RESULTS

While there were no OXT effects in accuracy, we found a significant interaction between treatment, sex, and gaze congruency in reaction times. That is, following OXT as compared to placebo, women displayed stronger interference of gaze direction, whereas in men no significant difference was observed. Besides, this interaction did not vary across different emotional expressions.

CONCLUSIONS

Our findings provide the first evidence for sex-dependent effects of OXT on the perception of ambiguous averted gaze. Given potential therapeutic applications of OXT to patients with developmental and psychiatric disorders, who are characterized as atypical in encoding gaze features, the findings suggest that rather different treatment outcomes could be anticipated in males and females.

Dynamic causal modeling of eye gaze processing in schizophrenia

BACKGROUND

Abnormal eye gaze perception is related to symptoms and social functioning in schizophrenia. However, little is known about the brain network mechanisms underlying these abnormalities. Here, we employed dynamic causal modeling (DCM) of fMRI data to discover aberrant effective connectivity within networks associated with eye gaze processing in schizophrenia.

METHODS

Twenty-seven patients (schizophrenia/schizoaffective disorder, SZ) and 22 healthy controls (HC) completed an eye gaze processing task during fMRI. Participants viewed faces with different gaze angles and performed explicit gaze discrimination (Gaze: "Looking at you?" yes/no) or implicit gaze processing (Gender: "male or female?"). Four brain regions, the secondary visual cortex (Vis), posterior superior temporal sulcus (pSTS), inferior parietal lobule (IPL), and posterior medial frontal cortex (pMFC) were identified as nodes for subsequent DCM analysis.

RESULTS

SZ and HC showed similar generative model structure, but SZ showed altered connectivity for specific self-connections, inter-regional connections during all gaze processing (reduced excitatory bottom-up and enhanced inhibitory top-down connections), and modulation by explicit gaze discrimination (increased frontal inhibition of visual cortex). Altered effective connectivity was significantly associated with poorer social cognition and functioning.

CONCLUSIONS

General gaze processing in SZ is associated with distributed cortical dysfunctions and bidirectional connectivity between regions, while explicit gaze discrimination involves predominantly top-down abnormalities in the visual system. These results suggest plausible neural mechanisms underpinning gaze processing deficits and may serve as bio-markers for intervention.

Quantifying the Wollaston Illusion

In the early 19th century, William H. Wollaston impressed the Royal Society of London with engravings of portraits. He manipulated facial features, such as the nose, and thereby dramatically changed the perceived gaze direction, although the eye region with iris and eye socket had remained unaltered. This Wollaston illusion has been replicated numerous times but never with the original stimuli. We took the eyes (pupil and iris) from Wollaston's most prominent engraving and measured their perceived gaze direction in an analog fashion. We then systematically added facial features (eye socket, eyebrows, nose, skull, and hair). These features had the power to divert perceived gaze direction by up to 20°, which confirms Wollaston's phenomenal observation. The effect can be thought of as an attractor effect, that is, cues that indicate a slight change in head orientation have the power to divert perceived gaze direction.

Using dual eye tracking to uncover personal gaze patterns during social interaction

We report the personal eye gaze patterns of people engaged in face-to-face getting acquainted conversation. Considerable differences between individuals are underscored by a stability of eye gaze patterns within individuals. Results suggest the existence of an eye-mouth gaze continuum. This continuum includes some people showing a strong preference for eye gaze, some with a strong preference for mouth gaze, and others distributing their gaze between the eyes and mouth to varying extents. Additionally, we found evidence of within-participant consistency not just for location preference but also for the duration of fixations upon the eye and mouth regions. We also estimate that during a 4-minute getting acquainted conversation mutual face gaze constitutes about 60% of conversation that occurs via typically brief instances of 2.2 seconds. Mutual eye contact ranged from 0-45% of conversation, via very brief instances. This was despite participants subjectively perceiving eye contact occurring for about 70% of conversation. We argue that the subjective perception of eye contact is a product of mutual face gaze instead of actual mutual eye contact. We also outline the fast activity of gaze movements upon various locations both on and off face during a typical face-to-face conversation.

Facing the Spectator

We investigated the familiar phenomenon of the uncanny feeling that represented people in frontal pose invariably appear to “face you” from wherever you stand. We deploy two different methods. The stimuli include the conventional one—a flat portrait rocking back and forth about a vertical axis—augmented with two novel variations. In one alternative, the portrait frame rotates whereas the actual portrait stays motionless and fronto-parallel; in the other, we replace the (flat!) portrait with a volumetric object. These variations yield exactly the same optical stimulation in frontal view, but become grossly different in very oblique views. We also let participants sample their momentary awareness through “gauge object” settings in static displays. From our results, we conclude that the psychogenesis of visual awareness maintains a number—at least two, but most likely more—of distinct spatial frameworks simultaneously involving “cue–scission.” Cues may be effective in one of these spatial frameworks but ineffective or functionally different in other ones.

How Long Did You Look At Me? The Influence of Gaze Direction on Perceived Duration and Temporal Sensitivity

Faces that exhibit emotionally negative expressions in mutual gaze have been shown to induce a dilation of perceived duration. The influence of gaze by itself on duration judgments, however, has rarely been investigated. We argue for a social interaction hypothesis, according to which humans should be highly accurate and precise (sensitive) when processing the temporal dynamics of mutual gaze. In three experiments, we investigated whether the direction of observed gaze affects perceived duration and temporal sensitivity. In Experiment 1, subjects did indeed estimate the duration of direct gaze more accurately as compared to the duration of averted gaze. In Experiments 2 and 3, subjects had to categorize direct and averted gaze stimuli as being short or long in duration (temporal bisection). Experiment 2 found temporal sensitivity (but not mean duration judgments) to be improved in cases of mutual gaze. In Experiment 3, the effect of mutual gaze on prolonged subjective duration did replicate, however, it was rather small. Moreover, temporal precision was not improved in the case of naturalistic stimuli. In sum, effects of mutual gaze on duration judgments are rather weak, and cannot be attributed to arousal, as such ratings did not differ between direct and averted gaze stimuli.