Neural Temporal Dynamics of Social Exclusion Elicited by Averted Gaze: An Event-Related Potentials Study

Skin conductance, facial EMG, and heart rate responses in multi-person gaze interactions

Previous literature has reported enhanced affective and attentional responses to faces with a direct vs. averted gaze. Typically, in these studies, only single faces were presented. However, daily social encounters often involve interaction with more than just one person. By employing an experimental set-up in which the participants believed they were interacting with two other persons, the present study, for the first time, investigated participants' skin conductance, facial electromyographic (EMG), and heart rate deceleration responses in multi-person eye contact situations. Responses were measured in two different social contexts; i) when the participants observed eye contact between two other persons ('vicarious eye contact effect'), and ii) when the participants themselves received direct gaze either from one or two persons. The results showed that the skin conductance, facial EMG, and heart rate deceleration responses elicited by observing two other persons making eye contact did not differ from those elicited by observing one person looking at the other while the other person was not reciprocating with their gaze. As a novel finding, the results showed that receiving direct gaze from two persons elicited greater affective arousal and zygomatic EMG, but smaller heart rate deceleration responses in participants than receiving direct gaze from one person only. The findings are thoroughly discussed and it is concluded that physiological responses in multi-person interaction contexts are influenced by many social effects between the interactors and can be markedly different from those observed in two-person interactions.

I looked at you, you looked at me, I smiled at you, you smiled at me—The impact of eye contact on emotional mimicry

Eye contact is an essential element of human interaction and direct eye gaze has been shown to have effects on a range of attentional and cognitive processes. Specifically, direct eye contact evokes a positive affective reaction. As such, it has been proposed that obstructed eye contact reduces emotional mimicry (i.e., the imitation of our counterpart’s emotions). So far, emotional mimicry research has used averted-gaze faces or unnaturally covered eyes (with black censor bars) to analyze the effect of eye contact on emotional mimicry. However, averted gaze can also signal disinterest/ disengagement and censor bars obscure eye-adjacent areas as well and hence impede emotion recognition. In the present study (N = 44), we used a more ecological valid approach by showing photos of actors who expressed either happiness, sadness, anger, or disgust while either wearing mirroring sunglasses that obstruct eye contact or clear glasses. The glasses covered only the direct eye region but not the brows, nose ridge, and cheeks. Our results confirm that participants were equally accurate in recognizing the emotions of their counterparts in both conditions (sunglasses vs. glasses). Further, in line with our hypotheses, participants felt closer to the targets and mimicked affiliative emotions more intensely when their counterparts wore glasses instead of sunglasses. For antagonistic emotions, we found the opposite pattern: Disgust mimicry, which was interpreted as an affective reaction rather than genuine mimicry, could be only found in the sunglasses condition. It may be that obstructed eye contact increased the negative impression of disgusted facial expressions and hence the negative feelings disgust faces evoked. The present study provides further evidence for the notion that eye contact is an important prerequisite for emotional mimicry and hence for smooth and satisfying social interactions.

Intelligent Classification Technique of Hand Motor Imagery Using EEG Beta Rebound Follow-Up Pattern

To apply EEG-based brain-machine interfaces during rehabilitation, separating various tasks during motor imagery (MI) and assimilating MI into motor execution (ME) are needed. Previous studies were focusing on classifying different MI tasks based on complex algorithms. In this paper, we implement intelligent, straightforward, comprehensible, time-efficient, and channel-reduced methods to classify ME versus MI and left- versus right-hand MI. EEG of 30 healthy participants undertaking motional tasks is recorded to investigate two classification tasks. For the first task, we first propose a “follow-up” pattern based on the beta rebound. This method achieves an average classification accuracy of 59.77% ± 11.95% and can be up to 89.47% for finger-crossing. Aside from time-domain information, we map EEG signals to feature space using extraction methods including statistics, wavelet coefficients, average power, sample entropy, and common spatial patterns. To evaluate their practicability, we adopt a support vector machine as an intelligent classifier model and sparse logistic regression as a feature selection technique and achieve 79.51% accuracy. Similar approaches are taken for the second classification reaching 75.22% accuracy. The classifiers we propose show high accuracy and intelligence. The achieved results make our approach highly suitable to be applied to the rehabilitation of paralyzed limbs.

Electrophysiological Correlates of Social Decision-making: An EEG Investigation of a Modified Ultimatum Game

Cooperation behaviors during social decision-making have been shown to be sensitive to manipulations of context. However, it remains unclear how aspects of context in dynamic social interactions, such as observed nonverbal behaviors, may modulate cooperation decisions and the associated neural mechanisms. In this study, participants responded to offers from proposers to split $10 in an Ultimatum Game following observation of proposer approach (friendly) or avoidance (nonfriendly) behaviors, displayed by dynamic whole-body animated avatars, or following a nonsocial interaction control condition. As expected, behavioral results showed that participants tended to have greater acceptance rates for unfair offers following observed nonverbal social interactions with proposers compared with control, suggesting an enhancing effect of social interactions on cooperative decisions. ERP results showed greater N1 and N2 responses at the beginning of social interaction conditions compared with control, and greater sustained and late positivity responses for observed approach and avoidance proposer behaviors compared with control. Event-related spectral perturbation (ERSP) results showed differential sensitivity within theta, alpha, and beta bands during observation of social interactions and offers that was associated with subsequent decision behaviors. Together, these results point to the impact of proposers' nonverbal behaviors on subsequent cooperation decisions at both behavioral and neural levels. The ERP and ERSP findings suggest modulated attention, monitoring, and processing of biological motion during the observed nonverbal social interactions, influencing the participants' responses to offers. These findings shed light on electrophysiological correlates of response to observed social interactions that predict subsequent social decisions.

Exploring neurophysiological markers of visual perspective taking: Methodological considerations

RATIONALE

For visual perspective taking (VPT) using the avatar task, examinations of neural processes using event related potentials (ERP) indicate a distinction between an early posterior perspective calculation process (P3) and a later frontal process (LFSW) managing perspective conflict. While it is unknown if these neural processes are affected in clinical populations, it is unclear if the avatar task can be applied to this group, due to the long duration and sensitivity to data loss. Thus, we performed a methodological study of the avatar task, testing the feasibility of a shortened experimental paradigm.

OBJECTIVE

To investigate whether previously reported behavioural and ERP effects in the avatar task can also be seen if analysing all trials (matching/non-matching) jointly, and whether they remain robust if only a subset of the data is analysed.

METHOD

Healthy individuals (n = 20) completed the avatar task with ERP measurement. ERP components (P3, LFSW) and behavioural data were investigated by A) comparing use of only matching trials (n = 384) versus all trials (n = 768), and B) examining if reduced duration of assessment, by analysing only a subset of the data, impacts ERP findings.

RESULTS

We observed minimal differences when analysing data from only matching trial types compared to all trial types. Further, ERP amplitudes and latency findings were replicated when analysing only a subset of the data.

CONCLUSIONS

The duration of the avatar task can be reduced to avoid long testing times, thus making it better suited for use in clinical populations.

The effect of eye gaze direction on emotional mimicry: A multimodal study with electromyography and electroencephalography

Emotional mimicry plays an important role in social interaction and is influenced by social context, especially eye gaze direction. However, the neural mechanism underlying the effect of eye gaze direction on emotional mimicry is unclear. Here, we explored how eye gaze direction influenced emotional mimicry with a combination of electromyography (EMG) and electroencephalography (EEG) techniques, which may provide a more comprehensive measure. To do this, we recorded facial EMG and scalp EEG signals simultaneously while participants observed emotional faces (happy vs. angry) with direct or averted gaze. Then, we split the EEG trials into two mimicry intensity categories (high mimicry intensity, HMI vs. low mimicry intensity, LMI) according to EMG activity. The ERP difference between HMI and LMI EEG trials revealed four ERP components (P50, P150, N200 and P300), and the effect of eye gaze direction on emotional mimicry was prominent on P300 at P7 and P8. Moreover, we also observed differences in the effect of eye gaze direction on mimicry of happy faces and angry faces, which were found on P300 at P7, as well as P150 at P7 and N200 at P7 and Pz. In short, the present study isolated the neural signals of emotional mimicry with a new multimodal method, and provided empirical neural evidence that eye gaze direction affected emotional mimicry.

Electrophysiological Correlates of Racial In-group Bias in Observing Nonverbal Social Encounters

Despite evidence identifying the role of group membership in social cognition, the neural mechanisms associated with the perception and evaluation of nonverbal behaviors displayed by in-group versus out-group members remain unclear. Here, 42 white participants underwent electroencephalographic recording while observing social encounters involving dynamic displays of nonverbal behaviors by racial in-group and out-group avatar characters. Dynamic behaviors included approach and avoidance poses and expressions, followed by the participants' ratings of the avatars displaying them. Behaviorally, participants showed longer RTs when evaluating in-group approach behavior compared with other behaviors, possibly suggesting increased interest and attention devoted to processing positive social encounters with their in-group members. Analyses of ERPs revealed differential sensitivity of the N450 and late positivity components to social cues, with the former showing initial sensitivity to the presence of a humanoid avatar character at the beginning of social encounters and the latter showing sensitivity to dynamic nonverbal behaviors displayed by the avatars. Moreover, time-frequency analysis of electroencephalography data also identified suppression of beta-range power linked to the observation of dynamic nonverbal behaviors. Notably, the magnitude of these responses was modulated by the degree of behavioral racial in-group bias. This suggests that differential neural sensitivity to nonverbal cues while observing social encounters is associated with subsequent in-group bias manifested in the evaluation of such encounters. Collectively, these findings shed light on the mechanisms of racial in-group bias in social cognition and have implications for understanding factors related to successful interactions with individuals from diverse racial backgrounds.

Social inclusion, but not exclusion, delays attentional disengagement from direct gaze

The present study investigated whether another person’s direct gaze holds a perceiver’s visuospatial attention and whether social exclusion or social inclusion would enhance this effect. Participants were socially excluded, socially included, or underwent a non-social control manipulation in a virtual ball-tossing game. The manipulation was followed by an attentional disengagement task, in which we measured manual response times in identification of peripheral stimuli shown to the left or right of centrally presented faces portraying direct or downward gaze. Contrary to our hypotheses, the response times were not, in general, longer for direct gaze trials than downward gaze trials, and exclusion did not increase the delay in direct gaze trials. Instead, we discovered that, in the social inclusion group, the response times were longer for direct gaze trials relative to downward gaze trials. Thus, social inclusion might have activated affiliation-related cognitive processes leading to delayed attentional disengagement from faces cueing affiliation.

Affective Eye Contact: An Integrative Review

In recent years, many studies have shown that perceiving other individuals' direct gaze has robust effects on various attentional and cognitive processes. However, considerably less attention has been devoted to investigating the affective effects triggered by eye contact. This article reviews research concerning the effects of others' gaze direction on observers' affective responses. The review focuses on studies in which affective reactions have been investigated in well-controlled laboratory experiments, and in which contextual factors possibly influencing perceivers' affects have been controlled. Two important themes emerged from this review. First, explicit affective evaluations of seeing another's direct versus averted gaze have resulted in rather inconsistent findings; some studies report more positive subjective feelings to direct compared to averted gaze, whereas others report the opposite pattern. These contradictory findings may be related, for example, to differences between studies in terms of the capability of direct-gaze stimuli to elicit feelings of self-involvement. Second, studies relying on various implicit measures have reported more consistent results; they indicate that direct gaze increases affective arousal, and more importantly, that eye contact automatically evokes a positively valenced affective reaction. Based on the review, possible psychological mechanisms for the positive affective reactions elicited by eye contact are described.