Don't stand so close to me: A behavioral and ERP study of preferred interpersonal distance

A friend in need is a friend indeed: Acute tandem rope skipping enhances inter-brain synchrony of socially avoidant individuals

Team-based physical activity (PA) can improve social cognition; however, few studies have investigated the neurobiological mechanism underlying this benefit. Accordingly, a hyper-scanning protocol aimed to determine whether the interbrain synchrony (IBS) is influenced by an acute bout of team-based PA (i.e., tandem rope skipping). Specifically, we had socially avoidant participants (SOA, N=15 dyads) and their age-matched controls (CO, N=16 dyads) performed a computer-based cooperative task while EEG was recorded before and after two different experimental conditions (i.e., 30-min of team-based PA versus sitting). Phase locking value (PLV) was used to measure IBS. Results showed improved frontal gamma band IBS after the team-based PA compared to sitting when participants received successful feedback in the task (Mskipping = 0.016, Msittting = -0.009, p = 0.082, ηp2 = 0.387). The CO group showed a larger change in frontal and central gamma band IBS when provided failure feedback in the task (Mskipping = 0.017, Msittting = -0.009, p = 0.075, ηp2 = 0.313). Thus, results suggest that socially avoidant individuals may benefit from team-based PA via improved interbrain synchrony. Moreover, our findings deepen our understanding of the neurobiological mechanism by which team-based PA may improve social cognition among individuals with or without social avoidance.

The space between us: The effect of perceived threat on discomfort distance and perceived pleasantness of interpersonal vicarious touch

The space we keep between ourselves and others allows us either to engage in close shared experiences or to distance ourselves for safety. Focusing primarily on the latter, previous studies have identified a link between interpersonal boundaries and perceived threat, perceptual discrimination including pain perception as well as how we move and behave as a result. Although interpersonal distancing has been studied in a range of contexts, a mechanistic way of how such spatial behaviour might alter how we perceive affective touch has yet to be investigated. Here we probe the effect of perceived threat of COVID-19 on interpersonal boundary preferences and perceived pleasantness of vicarious affective touch. Our results demonstrate that increased perceived threat from COVID-19 is associated with larger boundaries of discomfort distance. Moreover, we show a positive association between perceived threat and pleasantness of vicarious touch coming from a member of the household, but no association with outsider touch. Importantly, rather than focusing on the purely "positive" and prosocial functions of affective touch, these results bolster a novel perspective that socially-relevant cues guide both approach and avoidance behaviours.

Childhood maltreatment is linked to larger preferred interpersonal distances towards friends and strangers across the globe

Childhood maltreatment (CM) is thought to be associated with altered responses to social stimuli and interpersonal signals. However, limited evidence exists that CM is linked to larger comfortable interpersonal distance (CID) - the physical distance humans prefer towards others during social interactions. However, no previous study has investigated this association in a comprehensive sample, yielding sufficient statistical power. Moreover, preliminary findings are limited to the European region. Finally, it is unclear how CM affects CID towards different interaction partners, and whether CID is linked to social functioning and attachment. To address these outstanding issues, adults (N = 2986) from diverse cultures and socio-economic strata completed a reaction time task measuring CID towards an approaching stranger and friend. Higher CM was linked to a larger CID towards both friends and strangers. Moreover, insecure attachment and less social support were associated with larger CID. These findings demonstrate for the first time that CM affects CID across countries and cultures, highlighting the robustness of this association.

The impact of body image on social cognition: Fear of negative evaluation mediates the relationship between body surveillance and interpersonal distance in women

Interpersonal distance (IPD) refers to the distance naturally maintained during social interactions, while peripersonal space (PPS) refers to the immediate space surrounding the body, or the space within reaching distance. Previous research has preliminarily indicated that IPD is associated with body image disturbances. We sought to expand extant literature by exploring associations between aspects of positive and negative body image, IPD, and PPS. Seventy-five women from the United Kingdom aged 18-40 years completed measures of body appreciation, body image flexibility, body shame, body surveillance, and body dissatisfaction. IPD boundaries were estimated using a lab-based comfort-distance task, whereas PPS boundaries were estimated using an audio-tactile reaction-time task. Measures of body acceptance by others and fear of negative evaluation were completed as potential mediators. Overall, we identified positive associations between IPD, body surveillance, and fear of negative evaluation, with no statistically significant associations identified between the other indices. The association between active IPD and body surveillance was mediated by fear of negative evaluation, even after controlling for demographic factors. These findings suggest a nuanced relationship between IPD and body image-related factors, highlighting the role of social evaluation anxiety. Future investigations should use experimental designs to further understand these relationships and their implications.

How Socially Avoidant Emerging Adults Process Social Feedback during Human-to-Human Interaction after Social Rejection: An Event-Related Potential Study

Social avoidance refers to active non-participation in social activities, which is detrimental to healthy interpersonal interaction for emerging adults. Social rejection is a kind of negative social evaluation from others making people feel social pain. However, how socially avoidant emerging adults process social feedback information after experiencing social rejection has received less attention. The current study aimed to explore the differences in social interaction feedback processing after social rejection between a socially avoidant group (n = 16) and a comparison group (n = 16) in a human-to-human interaction context. Computer game tasks with two types of interaction (cooperation and competition) were used to record the event-related potentials when receiving social interaction feedback in two conditions (social rejection and control condition). The results showed that (1) the socially avoidant group had lower reward positivity amplitudes than the comparison group when receiving social feedback; (2) the socially avoidant group presented larger P300 amplitudes in the social rejection condition than in the control condition, but the comparison group did not; and (3) social rejection evoked more negative N1 amplitudes in the socially avoidant and comparison groups. The findings suggest that socially avoidant emerging adults may have flaws in reward sensitivity during interpersonal interaction, and they might also exert more attentional and emotional resources to social feedback after social rejection.

Perception of interpersonal distance and social distancing before and during COVID-19 pandemic

Since COVID-19 is easily transmitted among people in close physical proximity, the focus of epidemiological policy during the COVID-19 crisis included major restrictions on interpersonal distance. However, the way in which distance restrictions affected spatial perception is unclear. In the current study, we examined interpersonal distance preferences and perceptions at three time points: pre-pandemic, early post-pandemic, and late post-pandemic. The results indicate that following the pandemic outbreak, people perceived others as farther away than they actually were, suggesting that the distance restrictions were associated with an enlargement of perceived interpersonal distance. Interestingly, however, people maintained the same distance from one another as before the outbreak, indicating no change in actual distance behavior due to the risk of infection. These findings suggest that COVID-19 was associated with a change in the way distance is perceived, while in practice, people maintain the same distance as before. In contrast, COVID-related anxiety predicted both a preference for maintaining a greater distance and a bias toward underestimating perceived distance from others. Thus, individuals who were highly fearful of COVID-19 perceived other people to be closer than they actually were and preferred to maintain a larger distance from them. The results suggest that subjective risk can lead to an increased perception of danger and a subsequent change in behavior. Taken together, even when behaviors should logically change, the decision-making process can be based on distorted perceptions. This insight may be used to predict public compliance.

Looming Angry Faces: Preliminary Evidence of Differential Electrophysiological Dynamics for Filtered Stimuli via Low and High Spatial Frequencies

Looming motion interacts with threatening emotional cues in the initial stages of visual processing. However, the underlying neural networks are unclear. The current study investigated if the interactive effect of threat elicited by angry and looming faces is favoured by rapid, magnocellular neural pathways and if exogenous or endogenous attention influences such processing. Here, EEG/ERP techniques were used to explore the early ERP responses to moving emotional faces filtered for high spatial frequencies (HSF) and low spatial frequencies (LSF). Experiment 1 applied a passive-viewing paradigm, presenting filtered angry and neutral faces in static, approaching, or receding motions on a depth-cued background. In the second experiment, broadband faces (BSF) were included, and endogenous attention was directed to the expression of faces. Our main results showed that regardless of attentional control, P1 was enhanced by BSF angry faces, but neither HSF nor LSF faces drove the effect of facial expressions. Such findings indicate that looming motion and threatening expressions are integrated rapidly at the P1 level but that this processing relies neither on LSF nor on HSF information in isolation. The N170 was enhanced for BSF angry faces regardless of attention but was enhanced for LSF angry faces during passive viewing. These results suggest the involvement of a neural pathway reliant on LSF information at the N170 level. Taken together with previous reports from the literature, this may indicate the involvement of multiple parallel neural pathways during early visual processing of approaching emotional faces.

Attitudes to Interpersonal Touch in the Workplace in Autistic and non-Autistic Groups

Unemployment and underemployment have consistently been shown to be higher in autistic adults relative to non-autistic adults. This may be due, in part, to a lack of workplace accommodations being made for autistic people. One factor that may contribute to employment inequalities in autistic people is differences in attitudes towards interpersonal touch. This study acts as a preliminary investigation into whether employed autistic and non-autistic participants differ in their attitudes towards touch in the workplace, and in their loneliness and wellbeing. The current dataset was drawn from a larger online survey (the Touch Test) designed to explore attitudes and experiences towards touch. We found that employed autistic participants had more negative attitudes to general, social and workplace touch relative to non-autistic participants. Autistic participants also experienced greater loneliness and reduced wellbeing. Attachment-related anxiety was the only significant predictor of wellbeing in employed autistic adults. However, attachment-related anxiety, general attitudes to touch and the role of touch in the workplace predicted wellbeing in employed non-autistic adults. With regards to loneliness, general attitudes to touch and the role of touch in the workplace predicted loneliness in autistic participants. We also replicated the finding that a greater proportion of autistic participants were unemployed relative to non-autistic participants. Collectively, this research highlights the importance of considering touch in research investigating employment, and its impact on loneliness and wellbeing, in autistic participants.

Early threat perception is independent of later cognitive and behavioral control. A virtual reality-EEG-ECG study

Research on social threat has shown influences of various factors, such as agent characteristics, proximity, and social interaction on social threat perception. An important, yet understudied aspect of threat exposure concerns the ability to exert control over the threat and its implications for threat perception. In this study, we used a virtual reality (VR) environment showing an approaching avatar that was either angry (threatening body expression) or neutral (neutral body expression) and informed participants to stop avatars from coming closer under five levels of control success (0, 25, 50, 75, or 100%) when they felt uncomfortable. Behavioral results revealed that social threat triggered faster reactions at a greater virtual distance from the participant than the neutral avatar. Event-related potentials (ERPs) revealed that the angry avatar elicited a larger N170/vertex positive potential (VPP) and a smaller N3 than the neutral avatar. The 100% control condition elicited a larger late positive potential (LPP) than the 75% control condition. In addition, we observed enhanced theta power and accelerated heart rate for the angry avatar vs. neutral avatar, suggesting that these measures index threat perception. Our results indicate that perception of social threat takes place in early to middle cortical processing stages, and control ability is associated with cognitive evaluation in middle to late stages.

The effect of trait anxiety on the time course of self-relevant processing: Evidence from the perceptual matching task

Studies have widely reported that trait anxiety is associated with a range of cognitive biases toward external negative emotional stimuli. However, few studies have examined whether trait anxiety modulates intrinsic self-relevant processing. This study investigated the electrophysiological mechanism underlying trait anxiety's modulating effect on self-relevant processing. Event-related potentials (ERPs) were recorded while participants performed a perceptual matching task that assigned an arbitrary geometric shape to an association with a "self" or "non-self" label. Results showed larger N1 amplitudes under self-association than under friend-association conditions, and smaller P2 amplitudes for self- than for stranger-association conditions in individuals with high trait anxiety. However, these self-biases in the N1 and P2 stages were not observed in those with low trait anxiety until the later N2 stage, in which the self-association condition provoked smaller N2 amplitudes than the stranger-association condition. In addition, both high and low trait anxiety individuals showed larger P3 amplitudes for the self-association condition than for the friend- and stranger-association conditions. These findings suggest that, although both high and low trait anxiety individuals showed self-bias, high trait anxiety individuals distinguished between self-relevant and non-self-relevant stimuli at an earlier stage, which may reflect hypervigilance to self-relevant stimuli.

Interpersonal relationships modulate subjective ratings and electrophysiological responses of moral evaluations

This study explored how interpersonal relationships modulate moral evaluations in moral dilemmas. Participants rated moral acceptability in response to altruistic (prescriptive) and selfish (proscriptive) behavior conducted by allocators (i.e., a friend or stranger), toward the participants themselves or another stranger in a modified Dictator Game (Experiments 1 and 2). Event-related potential (ERP) data were recorded as participants observed the allocators' behavior (Experiment 2). Moral acceptability ratings showed that when the allocator was a friend, participants evaluated the friend's altruistic and selfish behavior toward another stranger as being less morally acceptable than when their friend showed the respective behavior toward the participants themselves. The ERP results showed that participants exhibited more negative medial frontal negativity (MFN) amplitude whether observing a friend's altruistic or selfish behavior toward a stranger (vs. participant oneself), indicating that friends' altruistic and selfish behaviors toward strangers (vs. participants) were processed as being less acceptable at the earlier and semi-automatic processing stage in brains. However, this effect did not emerge when the allocator was a stranger in subjective ratings and MFN results. In the later-occurring P3 component, no interpersonal relationship modulation occurred in moral evaluations. These findings suggest that interpersonal relationships affect moral evaluations from the second-party perspective.

Smaller preferred interpersonal distance for joint versus parallel action

During social interaction, humans prefer to keep a certain distance between themselves and other individuals. This preferred 'interpersonal distance' (IPD) is known to be sensitive to social context, and in the present study we aimed to further investigate the extent to which IPD is affected by the specific type of social interaction. In particular, we focused on the contrast between joint actions, where two or more individuals coordinate their actions in space and time to achieve a shared goal, and parallel actions, where individuals act alongside each other but individually. We predicted that joint action would be associated with a smaller preferred IPD compared to parallel action. Additionally, given that this research took place in the midst of the COVID-19 pandemic, we aimed to assess whether IPD preferences are affected by individuals' concerns about infection in general, as well as COVID-19 in particular. We predicted that higher individual concerns would be associated with greater preferred IPD. To test these hypotheses, we asked participants to imagine different social scenarios (involving either joint or parallel actions alongside a stranger) and indicate, on a visual scale, their preferred IPD. The results of two experiments (n = 211, n = 212) showed that participants preferred a shorter distance when they imagined acting jointly compared to when they imagined acting in parallel. Moreover, participants who reported higher discomfort for potential pathogen contact and who were more aware of the COVID-19 context in which the study took place preferred a larger IPD in general. Our results provide further evidence that different types of social interaction shape IPD preference. We discuss potential reasons for this phenomenon and highlight remaining questions for future research.

Up close and emotional: Electrophysiological dynamics of approaching angry faces

Recent evidence suggests that looming emotional faces are processed rapidly by the neural system, and that this apparent approach further interacts with emotion, causing an enhanced neural response for angry expressions. However, previous research has not demonstrated unequivocally if these effects are due to low-level visual features, or if they are indeed due to the emotional content of the stimuli. To address this question, the current study presented upright and inverted angry and neutral faces, which either expanded or contracted in size on a constant depth-cued background, such that they appeared to approach or retreat from the viewer. EEG/ERP measures were used to identify the time course of brain activity for these stimuli. The results showed that when faces were upright, both the P1 and N170 were enhanced for angry expressions, with the P1 being further increased with looming angry faces. The inversion of the faces caused an increase in both the P1 and N170 amplitudes, but no modulation was found for emotions. These findings show an early modulation of brain activity for upright looming angry faces and rule out the influence of low-level visual features as a contributing factor.

Correlation Between Aggressive Behavior and Impulsive and Aggressive Personality Traits in Stable Patients with Schizophrenia

Purpose

To explore the correlation between aggressive behavior and impulsive and aggressive personality traits in inpatients with schizophrenia.

Methods

In total, 367 inpatients with schizophrenia were divided into two groups: the aggressive group and the non-aggressive group. We assessed inpatients' psychotic symptoms as well as their aggressive and impulsive personality traits using the Positive and Negative Symptom Scale, the Barratt Impulsiveness Scale, and the Buss-Perry Aggression Questionnaire.

Results

Compared with the scores of inpatients in the non-aggressive group, the total Buss-Perry Aggression Questionnaire, subscale, and Barratt Impulsiveness Scale behavioral factor scores in those in the aggressive group were higher (p < 0.05). The results of logistic regression analysis suggested that a high Positive and Negative Symptom Scale positive factor score (odds ratio = 1.07) and a high Buss-Perry Aggression Questionnaire physical aggression score (odds ratio = 1.02) were risk factors for aggressive behavior.

Conclusion

Hospitalized patients with schizophrenia with more severe positive symptoms and aggressive traits may be more prone to aggressive behavior.

A new approach for social group detection based on spatio-temporal interpersonal distance measurement

Visual-based social group detection aims to cluster pedestrians in crowd scenes according to social interactions and spatio-temporal position relations by using surveillance video data. It is a basic technique for crowd behaviour analysis and group-based activity understanding. According to the theory of proxemics study, the interpersonal relationship between individuals determines the scope of their self-space, while the spatial distance can reflect the closeness degree of their interpersonal relationship. In this paper, we proposed a new unsupervised approach to address the issues of interaction recognition and social group detection in public spaces, which remits the need to intensely label time-consuming training data. First, based on pedestrians' spatio-temporal trajectories, the interpersonal distances among individuals were measured from static and dynamic perspectives. Combined with proxemics' theory, a social interaction recognition scheme was designed to judge whether there is a social interaction between pedestrians. On this basis, the pedestrians are clustered to identify if they form a social group. Extensive experiments on our pedestrian dataset “SCU-VSD-Social” annotated with multi-group labels demonstrated that the proposed method has outstanding performance in both accuracy and complexity.

Wearing a Mask Shapes Interpersonal Space during COVID-19 Pandemic

Social distancing norms have been promoted after the COVID-19 pandemic. In this work, we tested interpersonal space (IPS) in 107 subjects through a reaching-comfort distance estimation task. In the main experiment, subjects had to estimate the comfort and reach space between an avatar wearing or not wearing a face mask. We found that IPS was greater between avatars not wearing a mask with respect to stimuli with the mask on, while reaching space was not modulated. IPS increment in the NoMask condition with respect to the Mask condition correlated with anxiety traits, as shown with the State-Trait Anxiety Inventory, rather than with transient aspects related to the pandemic situation. In the control experiment, the avatars with a mask were removed to further explore the conditioning effect provided by the presence of the facial protection in the main experiment. We found a significant difference comparing this condition with the same condition of the main experiment, namely, the distances kept between avatars not wearing a mask in the main experiment were greater than those between the same stimuli in the control experiment. This showed a contextual adaptation of IPS when elements related to the actual pandemic situation were relevant. Additionally, no significant differences were found between the control experiment and the Mask condition of the main experiment, suggesting that participants had internalized social distancing norms and wearing a mask has become the new normal. Our results highlight the tendency of people in underestimating the risk of contagion when in the presence of someone wearing a mask.

Enhanced early ERP responses to looming angry faces

Although the brain is known to process threatening emotional stimuli and looming motion rapidly, little is known about how the emotion and motion interact. To address this question, two experiments were carried out which presented angry and neutral emotional faces on a depth-cued background that induced the perception of distance, or a non-cued background. Furthermore, faces either expanded or contracted in size such that they appeared to approach or recede from the viewer. EEG/ERP measures were used to identify the time course of brain activity for these looming and receding, angry and neutral emotional faces. The results of both experiments revealed that the P1 was enhanced by looming angry faces on the depth-cued background, compared to neutral approaching faces, as well as all receding faces, indicating an early interaction of emotion and motion within 100 ms of presentation. Angry expressions were also found to enhance the N170 regardless of movement. These findings suggest that processing of threat and looming motion interact at the very early stages of visual processing. Furthermore, as the modulating effect of looming motion on angry expressions only arose on the depth-cued background, the findings highlight the importance of approaching movements rather than sole increases in the retinal size of the stimuli.

Mate preference and brain oscillations: Initial romantic attraction is associated with decreases in alpha- and lower beta-band power

Initial romantic attraction (IRA) refers to a series of positive reactions (such as feelings of exhilaration and compulsive thinking) toward desirable potential partners, usually at initial or early‐stage encounters when no close relationship has yet been established. After decades of effort, the evolutionary value and key characteristics of IRA are well understood. However, the brain mechanisms associated with IRA are unclear. To address this question, we simulated a mate selection platform similar to that of Tinder. When participants assessed their romantic interest in potential partners on the platform, their electroencephalogram (EEG) signals were recorded in real time. The behavioral data demonstrated that IRA to ideal potential partners mainly reflects the dimensions of arousal and domination. The main study finding was that processing of the individual preference faces that resulted in IRA was associated with a decrease in power in the alpha and lower beta bands over the posterior and anterior sensor clusters; this occurred between 870 and 2,000 ms post‐stimulus. Key findings regarding event‐related potentials (ERPs) sensitive to individual stimuli preferences were replicated. The results support the hypothesis that brain oscillations in the alpha and lower beta range may reflect modulation in cortical activity associated with individual mate preferences.

Don't get too close to me: depressed and non-depressed survivors of child maltreatment prefer larger comfortable interpersonal distances towards strangers

BACKGROUND

Childhood maltreatment (CM) is frequently linked to interpersonal problems such as difficulties in social relationships, loneliness, and isolation. These difficulties might partly stem from troubles regulating comfortable interpersonal distance (CIPD).

OBJECTIVE

We experimentally investigated whether CM manifests in larger CIPD and whether all subtypes of CM (i.e., physical, emotional, or sexual abuse and physical or emotional neglect) affect CIPD.

METHODS

Using the stop-distance method (i.e. a team member approached participants until the latter indicated discomfort), we assessed CIPD in 84 adults with a self-reported history of CM (24 with depressive symptoms) and 57 adult controls without a history of CM (without depressive symptoms).

RESULTS

Adults with CM showed a larger CIPD (Mdn = 86 cm) than controls (Mdn = 68 cm), and CIPD was largest for those with CM combined with current depressive symptoms (Mdn = 145 cm) (p's < .047). In the latter group, all subtypes of CM were associated with a larger CIPD compared to controls (p's < .045). In the CM group without depressive symptoms, only those with emotional abuse (p = .040) showed a larger CIPD than controls.

CONCLUSIONS

These results add to findings of differential socio-emotional long-term consequences of CM, depending upon the subtype of CM. Future research should explore whether a larger CIPD has a negative impact on social functioning in individuals exposed to CM, particularly in those with depressive symptoms.

HIGHLIGHTS

Adults with child maltreatment (CM) prefer larger physical distances.• This effect is more pronounced in those with CM and depressive symptoms.• Troubled regulation of physical distance might contribute to interpersonal problems.

Roles of P300 and Late Positive Potential in Initial Romantic Attraction

Initial romantic attraction (IRA) refers to a series of positive reactions to potential romantic partners at the initial encounter; it evolved to promote mate selection, allowing individuals to focus their mating efforts on their preferred potential mates. After decades of effort, we now have a deeper understanding of the evolutionary value and dominant factors of IRA; however, little is known regarding the brain mechanisms related to its generation and evaluation. In this study, we combined classic event-related potential analysis with dipole-source analysis to examine electroencephalogram (EEG) signals generated while participants assessed their romantic interest in potential partners. The EEG signals were categorized into IRA-engendered and unengendered conditions based on behavioral indicators. We found that the faces elicited multiple late positivities, including P300 over the occipital-parietal regions and late positive potentials (LPPs) over the anterior regions. When compared to faces that did not engender IRA, faces that did engender IRA elicited (1) enhanced P300 over the parietal regions and heightened neural activity in the insula and cingulate cortex and (2) larger LPPs over the anterior regions and heightened neural activity in the orbitofrontal cortex, dorsolateral prefrontal cortex, cingulate cortex, frontal eye field, visual cortex, and insula. These results suggest IRA is generated and evaluated by an extensive brain network involved in emotion processing, attention control, and social evaluations. Furthermore, these findings indicate that P300 and LPP may represent different cognitive processes during IRA.

Opposing Association of Situational and Chronic Loneliness with Interpersonal Distance

Loneliness is a prevalent condition with adverse effects on physical and mental health. Evolutionary theories suggest it evolved to drive people to reconnect. However, chronic loneliness may result in a negative social bias and self-preservation behaviors, paradoxically driving individuals away from social interactions. Lonely people often feel they are not close to anyone; however, little is known about their interpersonal distance preferences. During COVID-19, many experienced situational loneliness related to actual social isolation. Therefore, there was a unique opportunity to examine both chronic and situational (COVID-19-related) loneliness. In the present study, 479 participants completed an online task that experimentally assessed interpersonal distance preferences in four conditions-passively being approached by a friend or a stranger, and actively approaching a friend or a stranger. Results show that high chronic loneliness was related to a greater preferred distance across conditions. Intriguingly, by contrast, high COVID-19-related loneliness was related to a smaller preferred distance across conditions. These findings provide further support for the evolutionary theory of loneliness: situational loneliness indeed seems to drive people towards reconnection, while chronic loneliness seems to drive people away from it. Implications for the amelioration of chronic loneliness are discussed based on these findings.

Neural Alterations in Interpersonal Distance (IPD) Cognition and Its Correlation with IPD Behavior: A Systematic Review

Background. Interpersonal distance (IPD) plays a critical role in a human being’s social life, especially during interpersonal interaction, and IPD is non-verbal social information and not only provides silent cues but also provides a secure space for personal relationships. IPD has been a research field of neural studies from the recent decade, researches had provided behavior and neural correlates of IPD. Objectives. This review aims to summarize the experimental paradigms of IPD-neural research, to reveal the neural activity processes associated with it, and to explore the correlation between IPD-neural activity and IPD-behavior. Methods. We conducted a standardized systematic review procedure, including the formal search method be adopted to seek out any type of studies related to IPD and brain, then devised them into categories to make a systematic review. Results. 17 articles met the inclusion criteria of the review, 5 event-related potential (ERP) studies measured the amplitude and latencies of ERPs, and 12 functional magnetic resonance imaging (fMRI) studies provided the neural activation during IPD tasks. In addition, the passive IPD experimental paradigm is the main experimental paradigm for exploring neural activity in IPD cognition, with the parietal lobe, motor areas, prefrontal lobe, and amygdala being the main brain areas involved. Functional connections between the identified brain regions were found and have a moderate correlation with IPD behavior. Conclusions. This review provides the neural activity of the IPD interaction process. However, the insufficient ecological validity of IPD tasks and ignore the initiative of people in IPD interaction. Therefore, there is a large research space on this topic. The work of the current systematic review contributed to linking the external performance and inner neural activities of IPD.

Altered social cognition in a community sample of women with disordered eating behaviours: a multi-method approach

Prior work suggests that individuals with an eating disorder demonstrate task-based and overall differences in sociocognitive functioning. However, the majority of studies assessed specifically anorexia nervosa and often employed a single experimental paradigm, providing a piecemeal understanding of the applicability of various lab tasks in denoting meaningful differences across diverse individuals. The current study was designed to address these outstanding issues. Participants were undergraduate females who self-identified as having an official (n = 18) eating disorder diagnosis or disordered eating behaviours with no diagnosis (n = 18), along with a control group (n = 32). Participants completed three social tasks of increasing complexity with different outcome measures, namely a gaze cueing task, passive video-watching using eyetracking, and a task to measure preferred social distance. Results diverged as a function of group across tasks; only the control group produced typical social attention effects, the disordered eating group looked significantly more at faces, and the eating disorder group demonstrated a significantly larger preferred social distance. These results suggest variations in task efficacy and demonstrate that altered sociocognitive functioning extends beyond official eating disorder diagnosis.

Representing strangers in personal space triggers coding of defensive hand movement

Our brain codes manipulable tools as possibilities for action, particularly for those surrounding the body. Recent studies showed people would adjust their motor program when observing others around their own bodies (i.e. in the personal space). However, it remained unclear whether representing a personal space invader can automatically trigger motor coding. To address this, we devised an interaction task to measure the activation of pushing movements in facing a stranger approaching into personal space. The LRP (lateralized readiness potential) analyses revealed that observing a stranger in personal space caused an initial LRP bias associated with pushing movements, and an LRP deflection before responding of pull, suggesting representing personal space invaders activated the motor coding of push. The behavioral results showed the personal space intrusion prolonged the reaction time of participants' subsequent instructed pulling responses. The results of experiment 2 confirmed the behavioral observation of experiment 1 and further revealed the relationship between the response bias of push and social anxiety. Together, the present study demonstrates representing a stranger in personal space activated coding of defensive hand movements and biased subsequent motor responses.

Social Distancing During A COVID-19 Lockdown Contributes to The Maintenance of Social Anxiety: A Natural Experiment

Background

The COVID-19 pandemic has led to extensive social distancing measures. For those suffering from social anxiety, social distancing coincides with a tendency to avoid social interactions. We used this natural experiment imposed by a COVID-19 lockdown to examine how mandated low social exposure influenced socially anxious university students, and compared their anxiety to that of socially anxious students in preceding academic years with no social distancing.

Methods

Ninety-nine socially anxious students were assessed for social anxiety symptoms at the beginning of the fall and spring semesters. Students from the 2019–2020 academic year (which included a lockdown followed by social distancing measures at the end of the fall semester) were compared to students from preceding years (2016–2019) on social anxiety levels.

Results

Whereas social anxiety decreased in socially anxious students from the fall to the spring semester in the years preceding the pandemic, during the 2019–2020 academic year social anxiety levels remained high and unchanged. These results held when controlling for depressive symptoms and when analyzing social anxiety items that cannot be confounded with COVID-19-related anxiety.

Conclusions

The current results suggest that reduced exposure to social situations may play a role in the maintenance of social anxiety. Alternative explanations are discussed.

More Than a Feeling-Interrelation of Trust Layers in Human-Robot Interaction and the Role of User Dispositions and State Anxiety

With service robots becoming more ubiquitous in social life, interaction design needs to adapt to novice users and the associated uncertainty in the first encounter with this technology in new emerging environments. Trust in robots is an essential psychological prerequisite to achieve safe and convenient cooperation between users and robots. This research focuses on psychological processes in which user dispositions and states affect trust in robots, which in turn is expected to impact the behavior and reactions in the interaction with robotic systems. In a laboratory experiment, the influence of propensity to trust in automation and negative attitudes toward robots on state anxiety, trust, and comfort distance toward a robot were explored. Participants were approached by a humanoid domestic robot two times and indicated their comfort distance and trust. The results favor the differentiation and interdependence of dispositional, initial, and dynamic learned trust layers. A mediation from the propensity to trust to initial learned trust by state anxiety provides an insight into the psychological processes through which personality traits might affect interindividual outcomes in human-robot interaction (HRI). The findings underline the meaningfulness of user characteristics as predictors for the initial approach to robots and the importance of considering users’ individual learning history regarding technology and robots in particular.

Mother-Infant Interaction Kinect Analysis (MIIKA): An automatic kinematic-based methodology for the investigation of interpersonal distance during early exchanges

Interpersonal distance is a core aspect of mother-child interaction. While conventional measures based on human coders do not fully capture the dynamics of this feature, computational methods provide automatic measures which can detect even small changes and more accurate estimates both spatially and temporally. Using RGB-D sensors (Microsoft Kinect V2), the present study describes a setup to automatically examine interpersonal distance during mother-child interactions, termed Mother-Infant Interaction Kinect Analysis (MIIKA). First, the laboratory setting and the data extraction method are described. By using an ad-hoc algorithm for kinematic data extraction, MIIKA returns three metrics: barycenter position (distance and velocity of approach and separation), movements (number of small, medium and large approaches and separations) and contributions (proportional contributions of mother and child to approaches and separations). Secondly, preliminary MIIKA metrics are described for a non-clinical mother-child dyad as an exemplification of the protocol. As interpersonal distance can be affected by contingent situations, we detected mother-infant full skeleton during three interactional contexts characterized by different kinds of dyadic exchanges: a free play session, a task-oriented activity and an emotionally arousing condition. Results highlighted similarities and differences between the three interactional contexts. MIIKA appears to be a promising setup to automatically examine interpersonal distance in early mother-child interactions.

No distance is too far between friends: associations of comfortable interpersonal distance with PTSD and anxiety symptoms in Israeli firefighters

Background: Previous research indicates that PTSD patients may show alterations in interpersonal distance regulation (IDR). However, it is not clear whether altered IDR is correlated with psychopathology after trauma and whether attentional processes might be involved in these alterations. Objective: The current study investigated IDR and attentional processing in a sample of Israeli firefighters. Method: Twenty-four participants completed an experimental IDR task as well as measures of PTSD and anxiety. During the task, event-related potentials were recorded to assess attentional processing as reflected in the P1 and N1 components. Results: Participants who did not choose a closer distance towards friends than strangers experienced greater anxiety. Moreover, participants who showed attentional avoidance towards strangers reported more PTSD symptoms. By contrast, participants who showed hypervigilant attention towards strangers reported greater anxiety. Conclusions: Our results demonstrate an association between IDR, PTSD, and anxiety after trauma. Future studies should re-investigate these associations in larger samples and explore potential implications for prevention and treatment.

Virtual Reality Immersion Rescales Regulation of Interpersonal Distance in Controls but not in Autism Spectrum Disorder

Interpersonal distance (IPD) is a simple social regulation metric which is altered in autism. We performed a stop-distance paradigm to evaluate IPD regulation in autism spectrum disorder (ASD) and control groups in a real versus a virtual environment mimicking in detail the real one. We found a bimodal pattern of IPDs only in ASD. Both groups showed high IPD correlations between real and virtual environments, but the significantly larger slope in the control group suggests rescaling, which was absent in ASD. We argue that loss of nuances like non-verbal communication, such as perception of subtle body gestures in the virtual environment, lead to changed regulation of IPD in controls, whilst ASD participants show similar deficits in perceiving such subtle cues in both environments.

The physiological correlates of interpersonal space

Interpersonal space (IPS) is the area around the body that individuals maintain between themselves and others during social interactions. When others violate our IPS, feeling of discomfort rise up, urging us to move farther away and reinstate an appropriate interpersonal distance. Previous studies showed that when individuals are exposed to closeness of an unknown person (a confederate), the skin conductance response (SCR) increases. However, if the SCR is modulated according to participant’s preferred IPS is still an open question. To test this hypothesis, we recorded the SCR in healthy participants when a confederate stood in front of them at various distances simulating either an approach or withdrawal movement (Experiment 1). Then, the comfort-distance task was adopted to measure IPS: participants stop the confederate, who moved either toward or away from them, when they felt comfortable with other’s proximity (Experiment 2). We found higher SCR when the confederate stood closer to participants simulating an IPS intrusion, compared to when the confederate moved farther away. Crucially, we provide the first evidence that SCR, acting as a warning signal, contributes to interpersonal distance preference suggesting a functional link between behavioral components of IPS regulation and the underlying physiological processes.

Association of Chronic Low Back Pain With Personal Space Regulation

Background: While most previous studies regarding patients with chronic low back pain (CLBP) mainly focused on pain, disability, psychological damage, and intervention measures, the effect of CLBP on personal space remains unclear. The study aimed to assess the personal space of patients with CLBP and healthy controls, explored the differences between the two groups, and examined whether pain, dysfunction, anxiety, and depression affected the personal space regulation. Methods: The cross-sectional study recruited 24 patients with CLBP and 24 healthy controls at Shanghai Shangti Orthopedic Hospital and Shanghai University of Sport, Shanghai, China, from December 2018 to January 2019. A stop-distance paradigm was applied to measure the comfortable and uncomfortable distance under four conditions. A self-rating anxiety scale (SAS) and a self-rating depression scale (SDS) were used to examine the anxiety and depression levels of all participants. The pain intensity and dysfunction in the CLBP group were evaluated by the numeric rating scale and Roland-Morris questionnaire (RMDQ), respectively. Results: When approaching another individual or when being approached, the interpersonal distance under all the conditions in the CLBP group significantly differed from that in the healthy control group with larger space distances (p < 0.01). Gender had a significant main effect on the regulation of personal space in patients with CLBP (p < 0.05). The average pain intensity, scores on RMDQ, SAS, and SDS had a significant positive correlation with the interpersonal distance under the Same or Opposite Gender condition (p < 0.05). Conclusion: People with CLBP show an atypical personal space behavior and indeed have a greater interpersonal distance to strangers. The higher the pain intensity, dysfunction, anxiety, and depression, the greater the interpersonal distance in patients with CLBP. In the future, the effect and underlying neural mechanisms of pain and negative emotions on social withdrawal in patients should be examined.

Biased distance estimation in social anxiety disorder: A new avenue for understanding avoidance behavior

OBJECTIVES

People regulate their interpersonal space appropriately to obtain a comfortable distance for interacting with others. Socially anxious individuals are especially prone to discomfort from and fear of physical closeness, leading them to prefer a greater interpersonal distance from others. Previous studies also indicate that fear can enhance the threat-related elements of a threatening stimulus. For example, spider phobia is associated with estimating spiders as bigger and faster than they actually are. Nonetheless, it is still unclear whether the preference of those with social anxiety disorder (SAD) to maintain greater distance from others is associated with biased estimations of interpersonal distance.

MATERIALS AND METHODS

A total of 87 participants (44 clinically diagnosed with SAD and 43 control) performed validated computerized and ecological tasks in a real-life setting while social space estimations and preferences were measured.

RESULTS

Participants with SAD felt comfortable when maintaining a greater distance from unfamiliar others compared to the control group and estimated unfamiliar others to be closer to them than they actually were. Moreover, the estimation bias predicted their preferred distance from strangers, indicating a strong association between estimation bias severity and actual approach-avoidance behavior.

CONCLUSION

Our findings indicate that distance estimation bias underlies avoidance behavior in SAD, suggesting the involvement of a new cognitive mechanism in personal space regulation.

Herding in human groups is related to high autistic traits

Herding is ubiquitous throughout all social life forms, providing beneficial outcomes. Here, we examine whether herding emerges spontaneously in human groups and whether it adheres to the core principles of herding observed in the animal kingdom. Using a computerized paradigm involving the movements of circles, we tested the emergence of spontaneous and intentional herding of 136 participants assigned into groups of four participants. Herding was assessed by measuring directional synchrony in the movements of the circles, level of cohesion, and separation between circles. We found that human groups tend to spontaneously herd, particularly in terms of directional synchrony, supporting the notion of a human herding instinct. We further asked whether individuals with high traits of Autism Spectrum Disorder (ASD) exhibit differences in their herding tendencies. Results indicated that individuals with high ASD traits showed greater social separation from the group, compared to individuals with low ASD traits. Moreover, we found diminished spontaneous synchrony, but intact instructed synchrony in the high vs. the low ASD traits group. We contend that humans spontaneously herd with their group and suggest that the spontaneous tendency to synchronize with others is diminished in individuals with high ASD traits, though it is recovered when synchronization is intentional.

Being mimicked affects inhibitory mechanisms of imitation

This study investigated the effects of being mimicked on automatic imitation indices and social cohesion. 180 female participants were either interactively mimicked or anti-mimicked. In the mimicry condition, a confederate topographically aligned, during anti-mimicry, misaligned, their behavior to the participants. Being mimicked may evoke a sense of overlap between self and other generated movements. This so-created self-other overlap may generalize to other forms of imitation and social cohesion. Here, we investigated the effects of being mimicked on automatic imitation indices, using the Imitation-Inhibition Task. These indices are the baseline corrected facilitation and inhibition index, and the interference index which depicts the relation between facilitation and inhibition. In case of a generalized self-other overlap, we expect an increase in the facilitation, inhibition, and interference index, after the Mimicry as compared to the Anti-Mimicry condition. We furthermore predicted that the modulation of the indices would predict higher social cohesion ratings. Yet, our results showed a lower inhibition index after being mimicked, respectively an increase after Anti-Mimicry, with no effects on social cohesion ratings. This suggests that potential self-other overlap after being mimicked does not generalize to automatic imitation indices. Instead, being mimicked may have increased self-regulatory processes, and task performance.

Interpersonal Distance During Real-Time Social Interaction: Insights From Subjective Experience, Behavior, and Physiology

Physical distance is a prominent feature in face-to-face social interactions and allows regulating social encounters. Close interpersonal distance (IPD) increases emotional responses during interaction and has been related to avoidance behavior in social anxiety. However, a systematic investigation of the effects of IPD on subjective experience combined with measures of physiological arousal and behavioral responses during real-time social interaction has been missing. Virtual Reality allows for a controlled manipulation of IPD while maintaining naturalistic social encounters. The present study investigates IPD in social interaction using a novel paradigm in Virtual Reality. Thirty-six participants approached virtual agents and engaged in short interactions. IPD was varied between 3.5 and 1 m by manipulating the distance at which agents reacted to the participant's approach. Closer distances were rated as more arousing, less pleasant, and less natural than longer distances and this effect was significantly modulated by social anxiety scores. Skin conductance responses were also increased at short distances compared to longer distances. Finally, an interaction of IPD and social anxiety was observed for avoidance behavior, measured as participants' backward motion during interaction, with stronger avoidance related to close distances and high values of social anxiety. These results highlight the influence of IPD on experience, physiological response, and behavior during social interaction. The interaction of social anxiety and IPD suggests including the manipulation of IPD in behavioral tests in Virtual Reality as a promising tool for the treatment of social anxiety disorder.

Different neural activations for an approaching friend versus stranger: Linking personal space to numerical cognition

INTRODUCTION

Typically, humans place themselves at a preferred distance from others. This distance is known to characterize human spatial behavior. Here, we focused on neurocognitive conditions that may affect interpersonal distances. The current study investigated whether neurocognitive deficiencies in numerical and spatial knowledge may affect social perception and modulate personal space.

METHOD

In an event-related potential (ERP) study, university students with developmental dyscalculia (DD) and typically developing control participants were given a computerized version of the comfortable interpersonal distance task, in which participants were instructed to press the spacebar when they began to feel uncomfortable by the approach of a virtual protagonist.

RESULTS

Results showed that students with deficiencies in numerical and spatial skills (i.e., DD) demonstrated reduced variability in their preferred distance from an approaching friend. Importantly, DD showed decreased amplitude of the N1 wave in the friend condition.

CONCLUSION

These results suggest that people coping with deficiencies in spatial cognition have a less efficient allocation of spatial attention in the service of processing personal distances. Accordingly, the study highlights the fundamental role of spatial neurocognition in organizing social space.

Biased estimations of interpersonal distance in non-clinical social anxiety

Previous studies have indicated that socially-anxious individuals prefer to maintain a greater interpersonal distance from others, specifically from strangers. Notwithstanding, it has yet to be examined whether this preference for distance is associated with estimating the physical interpersonal distance in a distorted manner. In the current study, 100 participants performed a computerized task that measured estimated distance (Study 1). An additional sample of 75 participants performed the same task for the purpose of replication, and further took part in a new task that measured estimated distance from a stranger in a real-life setting (Study 2). In both studies social anxiety correlated with estimating the interpersonal distance from strangers as shorter. Furthermore, ones' preferred distance from a stranger was predicted by this distance estimation bias. Taken together, our findings are the first to reveal distance estimation bias in social anxiety, suggesting a role for distorted distance estimation in avoidance behavior.

Clinical Profile of Autism Spectrum Disorder in a Pediatric Population from Northern Mexico

Autism spectrum disorder (ASD) is a neurodevelopmental condition classified based on needs of support, in order to address impairments in the areas of social communication and restricted and repetitive behavior. The aim of this work is to describe the main clinical features of the ASD severity levels in a group of Mexican pediatric patients. The results show firstly that this condition was more frequent in males than females. Secondly, an inverse relationship was found between the intellectual coefficient and the level of severity of the disorder. Thirdly, deficits in social reciprocity and communication were more evident in Level 3, than in Levels 1 and 2, while the difference was less evident in restricted and repetitive patterns of behavior.

Consequences of Confronting Patronizing Help for People with Disabilities: Do Target Gender and Disability Type Matter?

People with disabilities face a dilemma in dealing with patronizing help: Although accepting unsolicited assistance can incur psychological costs, confronting the helper has been shown to incur interpersonal penalties. The present research explored whether the consequences of confronting patronizing help vary across target gender and disability type. A vignette paradigm introduced participants to various interactions between adults with and without disabilities. Study 1 (N = 137) showed that, when blind targets confronted help that was clearly patronizing, they were rated as ruder and less warm after (vs. before) confronting regardless of their gender. Study 2 (N = 368) showed that, although both blind and wheelchair-using targets were rated as less warm and ruder after (vs. before) confronting, blind targets were penalized more, and patronizing behavior toward blind targets was perceived as more appropriate. These results highlight the importance of considering intersectionality and cross-disability heterogeneity when examining the multifaceted experience of ableism.

When social and action spaces diverge: A study in children with typical development and autism

The space around the body has been defined as action space ( peripersonal space) and a social space ( interpersonal space). Within the current debate about the characteristics of these spaces, here we investigated the functional properties and plasticity of action and social space in developmental age. To these aims, children with typical development and autism spectrum disorders were submitted to Reaching- and Comfort-distance tasks, to assess peripersonal and interpersonal space, respectively. Participants approached a person (confederate) or an object and stopped when they thought they could reach the stimulus (Reaching-distance task), or they felt comfortable with stimulus’ proximity (Comfort-distance task). Both tasks were performed before and after a cooperative tool-use training, in which participant and confederate actively cooperated to reach tokens by using either a long (Experiment 1) or a short (Experiment 2) tool. Results showed that in both groups, peripersonal space extended following long-tool-use but not short-tool-use training. Conversely, in typical development, but not in autism spectrum disorders children, interpersonal space toward confederate reduced following the cooperative tool-use training. These findings reveal that action and social spaces are functionally dissociable both in typical and atypical development, and that action but not social space regulation is intact in children with autism.

Loneliness predicts a preference for larger interpersonal distance within intimate space

Loneliness is thought to serve as an adaptive signal indicating the need to repair or replace salutary social connections. Accordingly, loneliness may influence preferences for interpersonal distance. If loneliness simply motivates a desire to socially reconnect, then loneliness may be associated with a preference for smaller interpersonal distances. According to the evolutionary model of loneliness, however, loneliness also signals an inadequacy of mutual aid and protection, augmenting self-preservation motives. If loneliness both increases the motivation to reconnect and increases the motivation for self-protection, then the resulting approach-avoidance conflict should produce a preference for larger interpersonal distance, at least within intimate (i.e., proximal) space. Here, we report two survey-based studies of participants’ preferences for interpersonal distance to distinguish between these competing hypotheses. In Study 1 (N = 175), loneliness predicted preferences for larger interpersonal distance within intimate space net gender, objective social isolation, anxiety, depressive symptomatology, and marital status. In Study 2 (N = 405), we replicated these results, and mediation analyses indicated that measures of social closeness could not adequately explain our findings. These studies provide compelling evidence that loneliness predicts preferences for larger interpersonal distance within intimate space, consistent with predictions from the evolutionary model of loneliness.

Sleep loss causes social withdrawal and loneliness

Loneliness and social isolation markedly increase mortality risk, and are linked to numerous mental and physical comorbidities, including sleep disruption. But does sleep loss causally trigger loneliness? Here, we demonstrate that a lack of sleep leads to a neural and behavioral phenotype of social withdrawal and loneliness; one that can be perceived by other members of society, and reciprocally, makes those societal members lonelier in return. We propose a model in which sleep loss instigates a propagating, self-reinforcing cycle of social separation and withdrawal.

Loneliness markedly increases mortality and morbidity, yet the factors triggering loneliness remain largely unknown. This study shows that sleep loss leads to a neurobehavioral phenotype of human social separation and loneliness, one that is transmittable to non-sleep-deprived individuals.

The role of oxytocin in implicit personal space regulation: An fMRI study

Personal space, defined as the distance individuals choose to maintain between themselves and others, is an indicator of affiliation and closeness. Most paradigms that measure personal space preferences involve explicit choice and therefore fail to examine the implicit aspects of such preferences. In the current study, we sought to investigate an implicit form of interpersonal space that is more closely related to real-life situations involving affiliation. We studied the effects of oxytocin (OT) on neural networks that involve affiliation and tested the impact on personal space preferences. In a double-blind placebo-controlled study, we asked participants to choose between two rooms that differed only in the distances between two stimuli. The stimuli were either social stimuli (two chairs) or non-social stimuli (table and plant). The behavioral results showed that OT caused participants to choose a closer space in social blocks but did not affect their choices in non-social blocks. Imaging results revealed an interaction between stimulus and treatment (OT/PL) in the dorsal striatum, an area that is related to approach motivation and is part of the reward circuitry. Specifically, OT increased activity in the dorsal striatum in the social blocks and decreased this activity in the non-social blocks. The results of the study strengthen the social salience theory regarding OT, indicating that OT does not uniformly affect all social responses and that context has a determining impact on our behavior.

Individuals with Borderline Personality Disorder show larger preferred social distance in live dyadic interactions

Personal space regulation is a key component of effective social engagement. Personal space varies among individuals and with some mental health conditions. Simulated personal space intrusions in Borderline Personality Disorder (BPD) reveal larger preferred interpersonal distance in that setting. These findings led us to conduct the first test of live interpersonal distance preferences in symptoms in BPD. With direct observation of subjects' personal space behavior in the stop-distance paradigm, we found a 2-fold larger preferred interpersonal distance in BPD than control (n = 30, n = 23). We discuss this result in context of known biology and etiology of BPD. Future work is needed to identify neural circuits underlying personal space regulation in BPD, individual differences in preferred interpersonal distance in relation to specific symptoms and relationship to recovery status.