Abnormalities in early visual processes are linked to hypersociability and atypical evaluation of facial trustworthiness: An ERP study with Williams syndrome

Distrust before first sight? Examining knowledge- and appearance-based effects of trustworthiness on the visual consciousness of faces

The present EEG study with 32 healthy participants investigated whether affective knowledge about a person influences the visual awareness of their face, additionally considering the impact of facial appearance. Faces differing in perceived trustworthiness based on appearance were associated with negative or neutral social information and shown as target stimuli in an attentional blink task. As expected, participants showed enhanced awareness of faces associated with negative compared to neutral social information. On the neurophysiological level, this effect was connected to differences in the time range of the early posterior negativity (EPN)-a component associated with enhanced attention and facilitated processing of emotional stimuli. The findings indicate that the social-affective relevance of a face based on emotional knowledge is accessed during a phase of attentional enhancement for conscious perception and can affect prioritization for awareness. In contrast, no clear evidence for influences of facial trustworthiness during the attentional blink was found.

Dissociation of early and late face-related processes in autism spectrum disorder and Williams syndrome

Background

Williams syndrome (WS) and Autism Spectrum Disorders (ASD) are neurodevelopmental conditions associated with atypical but opposite face-to-face interactions patterns: WS patients overly stare at others, ASD individuals escape eye contact. Whether these behaviors result from dissociable visual processes within the occipito-temporal pathways is unknown.

Using high-density electroencephalography, multivariate signal processing algorithms and a protocol designed to identify and extract evoked activities sensitive to facial cues, we investigated how WS (N = 14), ASD (N = 14) and neurotypical subjects (N = 14) decode the information content of a face stimulus.

Results

We found two neural components in neurotypical participants, both strongest when the eye region was projected onto the subject's fovea, simulating a direct eye contact situation, and weakest over more distant regions, reaching a minimum when the focused region was outside the stimulus face. The first component peaks at 170 ms, an early signal known to be implicated in low-level face features. The second is identified later, 260 ms post-stimulus onset and is implicated in decoding salient face social cues.

Remarkably, both components were found distinctly impaired and preserved in WS and ASD. In WS, we could weakly decode the 170 ms signal based on our regressor relative to facial features, probably due to their relatively poor ability to process faces’ morphology, while the late 260 ms component was highly significant. The reverse pattern was observed in ASD participants who showed neurotypical like early 170 ms evoked activity but impaired late evoked 260 ms signal.

Conclusions

Our study reveals a dissociation between WS and ASD patients and points at different neural origins for their social impairments.

Sensory Processing in Williams Syndrome: Individual differences and changes over time

This study examined individual differences as well as the development of sensory processing difficulties in children with Williams syndrome (WS) using a cross-sectional (Experiment 1) and longitudinal design (Experiment 2). In Experiment 1, a clustering approach of sensory processing scores suggested two groups. Experiment 2 showed that the clusters identified in Experiment 1 were not stable across development, especially for those with high sensory impairments at either time point. Yet, most children experienced high impairments in sensory registration at both time points, suggesting impaired registration is a core phenotype of sensory processing in children with WS across development. Possible mechanisms, limitations and implications are discussed.

Face first impression of trustworthiness in Williams Syndrome: Dissociating automatic vs decision based perception

Humans make rapid decisions of trustworthiness based on facial appearance. Williams Syndrome (WS) is a genetic disorder associated with hypersociability toward strangers, suggesting a disruption in trust assessment. We recorded eye-movements in neurotypically-developed (TD) participants (N = 21) and in patients with WS (N = 22) as we presented pairs of computer-generated faces, pre-rated as trustworthy or untrustworthy. In a spontaneous visual preference task, TD participants gazed significantly longer at trustworthy faces while patients with WS showed no preferences for either face-type. Next, in a decision task, participants selected the face that they judged consistent with one of three social descriptions relating to high levels of trust. Both groups gazed longer at trustworthy faces and made correct matches with the corresponding social descriptions. Improvements by patients with WS in the decision task were contingent on outcomes measured on the emotional NEPSY scale. We conclude that while spontaneous representation of trustworthiness is impaired in WS, top-down mechanisms of trust recognition appear partially preserved.

The Effect of Trust on Gaze-Mediated Attentional Orienting

The last two decades have witnessed growing interest in the study of social cognition and its multiple facets, including trust. Interpersonal trust is generally understood as the belief that others are not likely to harm you. When meeting strangers, judgments of trustworthiness are mostly based on fast evaluation of facial appearance, unless information about past behavior is available. In the past decade, studies have tried to understand the complex relationship between trust and gaze-cueing of attention (GCA) (i.e., attentional orienting following another person’s gaze). This review will focus on the studies that used a gaze-cueing paradigm to explore this relationship. While the predictivity of the gaze-cue seems to consistently influence trustworthiness judgments, the impact of trust on gaze-cueing is less clear. Four studies found enhanced gaze-cueing effects with trustworthy faces; one found stronger effects of gaze-cueing with faces associated with undesirable behavior, but only when the observer’s personal evaluations were taken into account. Four studies did not observe an effect of trust on gaze-cueing. Overall, studies have highlighted the complexity of this relationship, suggesting that multiple factors (including age, gender, the characteristics of the observer, and whether or not a threat is perceived) are likely to intervene in the interplay between trust and gaze-triggered attentional orienting. After discussing results in the context of existing theories of gaze-cueing and trust, we conclude that further investigation is needed to better understand this relationship and the contribution of social factors to attentional shifts guided by gaze.

The sociability spectrum: evidence from reciprocal genetic copy number variations

Sociability entails some of the most complex behaviors processed by the central nervous system. It includes the detection, integration, and interpretation of social cues and elaboration of context-specific responses that are quintessentially species-specific. There is an ever-growing accumulation of molecular associations to autism spectrum disorders (ASD), from causative genes to endophenotypes across multiple functional layers; these however, have rarely been put in context with the opposite manifestation featured in hypersociability syndromes. Genetic copy number variations (CNVs) allow to investigate the relationships between gene dosage and its corresponding phenotypes. In particular, CNVs of the 7q11.23 locus, which manifest diametrically opposite social behaviors, offer a privileged window to look into the molecular substrates underlying the developmental trajectories of the social brain. As by definition sociability is studied in humans postnatally, the developmental fluctuations causing social impairments have thus far remained a black box. Here, we review key evidence of molecular players involved at both ends of the sociability spectrum, focusing on genetic and functional associations of neuroendocrine regulators and synaptic transmission pathways. We then proceed to propose the existence of a molecular axis centered around the paradigmatic dosage imbalances at the 7q11.23 locus, regulating networks responsible for the development of social behavior in humans and highlight the key role that neurodevelopmental models from reprogrammed pluripotent cells will play for its understanding.

Neural time course and brain sources of facial attractiveness vs. trustworthiness judgment

Prior research has shown that the more (or less) attractive a face is judged, the more (or less) trustworthy the person is deemed and that some common neural networks are recruited during facial attractiveness and trustworthiness evaluation. To interpret the relationship between attractiveness and trustworthiness (e.g., whether perception of personal trustworthiness may depend on perception of facial attractiveness), we investigated their relative neural processing time course. An event-related potential (ERP) paradigm was used, with localization of brain sources of the scalp neural activity. Face stimuli with a neutral, angry, happy, or surprised expression were presented in an attractiveness judgment, a trustworthiness judgment, or a control (no explicit social judgment) task. Emotional facial expression processing occurred earlier (N170 and EPN, 150-290 ms post-stimulus onset) than attractiveness and trustworthiness processing (P3b, 400-700 ms). Importantly, right-central ERP (C2, C4, C6) differences reflecting discrimination between "yes" (attractive or trustworthy) and "no" (unattractive or untrustworthy) decisions occurred at least 400 ms earlier for attractiveness than for trustworthiness, in the absence of LRP motor preparation differences. Neural source analysis indicated that facial processing brain networks (e.g., LG, FG, and IPL-extending to pSTS), also right-lateralized, were involved in the discrimination time course differences. This suggests that attractiveness impressions precede and might prime trustworthiness inferences and that the neural time course differences reflect truly facial encoding processes.

A Different Brain: Anomalies of Functional and Structural Connections in Williams Syndrome

We describe the results of a functional and structural brain connectivity analysis comparing a homogeneous group of 10 young adults with Williams Syndrome (WS; 3 females, age 20. 7 ± 3.7 years, age range 17.4–28.7 years) to a group of 18 controls of similar age (3 females, age 23.9 ± 4.4 years, age range 16.8–30.2), with the aim to increase knowledge of the structure – function relationship in WS. Subjects underwent a 3T brain MRI exam including anatomical, functional (resting state) and structural (diffusion MRI) sequences. We found convergent anomalies in structural and functional connectivity in the WS group. Altered Fractional Anisotropy (FA) values in parieto-occipital regions were associated with increased connectivity in the antero-posterior pathways linking parieto-occipital with frontal regions. The analysis of resting state data showed altered functional connectivity in the WS group in main brain networks (default mode, executive control and dorsal attention, sensori-motor, fronto—parietal, ventral stream). The combined analysis of functional and structural connectivity displayed a different pattern in the two groups: in controls the highest agreement was found in frontal and visual areas, whereas in WS patients in posterior regions (parieto-occipital and temporal areas). These preliminary findings may reflect an altered “wiring” of the brain in WS, which can be driven by hyper-connectivity of the posterior regions as opposed to disrupted connectivity in the anterior areas, supporting the hypothesis that a different brain (organization) could be associated with a different (organization of) behavior in Williams Syndrome.