Culture, sex and social context influence brain-to-brain synchrony: an fNIRS hyperscanning study

BACKGROUND

Unique interpersonal synchrony occurs during every social interaction, and is shaped by characteristics of participating individuals in these social contexts. Additionally, depending on context demands, interpersonal synchrony is also altered. The study therefore aims to investigate culture, sex, and social context effects simultaneously in a novel role-play paradigm. Additionally, the effect of personality traits on synchrony was investigated across cultures, and a further exploratory analysis on the effects of these variables on pre- and post-session empathy changes was conducted.

METHODS

83 dyads were recruited in two waves from Singapore and Italy and took part in a within-subjects session where they interacted with each other as themselves (Naturalistic Conversation) and as others (Role-Play and Role Reversal). Big Five Inventory (administered pre-session) and Interpersonal Reactivity Index (administered pre- and post-session) were used as measures of personality and empathy respectively, while synchrony was measured using hyperscanning functional near-infrared spectroscopy in the prefrontal cortex. After data-preprocessing and preliminary analyses, a mixture of multiple linear regression and exploratory forward stepwise regression models were used to address the above study aims.

RESULTS

Results revealed significant main and interaction effects of culture, sex and social context on brain-to-brain synchrony, particularly in the medial left cluster of the prefrontal cortex, and a unique contribution of extraversion and openness to experience to synchrony in the Italian cohort only. Finally, culture-driven differences in empathy changes were identified, where significant increases in empathy across sessions were generally only observed within the Singaporean cohort.

CONCLUSIONS

Main findings indicate lowered brain-to-brain synchrony during role-playing activities that is moderated by the dyad's sex make-up and culture, implying differential processing of social interactions that is also influenced by individuals' background factors. Findings align with current literature that role-playing is a cognitively demanding activity requiring greater levels of self-regulation and suppression of self-related cognition as opposed to interpersonal co-regulation characterized by synchrony. However, the current pattern of results would be better supported by future studies investigating multimodal synchronies and corroboration.

Sex and stress interactions in fear synchrony of mouse dyads

Socially coordinated threat responses support the survival of animal groups. Given their distinct social roles, males and females must differ in such coordination. Here, we report such differences during the synchronization of auditory-conditioned freezing in mouse dyads. To study the interaction of emotional states with social cues underlying synchronization, we modulated emotional states with prior stress or modified the social cues by pairing unfamiliar or opposite-sex mice. In same-sex dyads, males exhibited more robust synchrony than females. Stress disrupted male synchrony in a prefrontal cortex-dependent manner but enhanced it in females. Unfamiliarity moderately reduced synchrony in males but not in females. In dyads with opposite-sex partners, fear synchrony was resilient to both stress and unfamiliarity. Decomposing the synchronization process in the same-sex dyads revealed sex-specific behavioral strategies correlated with synchrony magnitude: following partners' state transitions in males and retroacting synchrony-breaking actions in females. Those were altered by stress and unfamiliarity. The opposite-sex dyads exhibited no synchrony-correlated strategy. These findings reveal sex-specific adaptations of socio-emotional integration defining coordinated behavior and suggest that sex-recognition circuits confer resilience to stress and unfamiliarity in opposite-sex dyads.

Nonverbal Synchrony in Technology-Mediated Interviews: A Cross-Cultural Study

Technology-mediated communication has changed the way we interact. Since the onset of the COVID-19 pandemic in March 2020, this trend became even more pronounced. Media interviews are no exception. Yet, studies on nonverbal behaviors, especially nonverbal synchrony during such mediated settings, have been scarce. To fill the research gap, this study investigated synchronized patterns between interview hosts’ and guests’ facial emotional displays and upper body movement during mediated interviews recorded in the countries in Western (mainly the US, with the addition of the UK) and Eastern cultures (Japan). The interviews were categorized into information- or entertainment-driven interviews, depending on the social attributes of the guest. The time series of the valence in facial displays and upper body movement was automatedly measured using FaceReader and Motion Energy Analysis software, respectively, which was analyzed in terms of simultaneous movements, a primary component of synchrony. As predicted, facial synchrony was more prevalent in information-driven interviews, supporting the motivational and strategic account of synchrony. In addition, female-hosted interviews had a higher degree of synchrony, especially in information-driven interviews. Similar patterns were seen in movement synchrony, although not significant. This study is the first evidence of synchrony in technology-mediated interviews in which a host and a guest appear on split-screen to inform or entertain audiences. However, no cultural differences in synchrony were observed. Situational demands in front of the interactants and the goal-driven nature of communication seemed to play a more prominent role than cultural differences in nonverbal synchrony.

Dyadic nonverbal synchrony during pre and post music therapy interventions and its relationship to self-reported therapy readiness

Nonverbal interpersonal synchronization has been established as an important factor in therapeutic relationships, and the differentiation of who leads the interaction appears to provide further important information. We investigated nonverbal synchrony - quantified as the coordination of body movement between patient and therapist. This was observed in music therapy dyads, while engaged in verbal interaction before and after a music intervention in the session. We further examined associations with patients' self-reported therapy readiness at the beginning of the session. Eleven neurological in-patients participated in this study. Our results showed an increase in both nonverbal synchrony and patient leading after the music intervention. A significant negative correlation was found between self-reported therapy readiness and nonverbal synchrony after the music intervention. These findings point to the empathic ability of the music therapist to sense patients' therapy readiness. Higher patient leading in nonverbal synchrony after the music intervention may thus indicate that the music intervention may have allowed dyadic entrainment to take place, potentially increasing self-regulation and thus empowering patients.

Nonverbal synchrony in subjects with hearing impairment and their significant others

Introduction

Hearing loss has a great impact on the people affected, their close partner and the interaction between both, as oral communication is restricted. Nonverbal communication, which expresses emotions and includes implicit information on interpersonal relationship, has rarely been studied in people with hearing impairment (PHI). In psychological settings, non-verbal synchrony of body movements in dyads is a reliable method to study interpersonal relationship.

Material and methods

A 10-min social interaction was videorecorded in 39 PHI (29 spouses and 10 parent-child dyads) and their significant others (SOs). Nonverbal synchrony, which means the nonverbal behaviors of two interacting persons (referring to both general synchrony and the role of leading) and verbal interaction (percentage of speech, frequency of repetitions, and queries) were analyzed by computer algorithms and observer ratings. Hearing-related quality of life, coping mechanisms, general psychopathology, quality of relationship, and burden of hearing loss experienced by SOs were assessed using questionnaires.

Results

In the 39 dyads, true nonverbal synchrony differed from pseudosynchrony [t_(43.4) = 2.41; p = 0.02] with a medium effect size (d = 0.42). Gender of PHI had a significant effect on general synchrony (p = 0.025) and on leading by SOs (p = 0.017). Age gap correlated with synchronic movements (p = 0.047). Very short duration of hearing impairment was associated with lower nonverbal synchrony in the role of leading by SOs (p = 0.031). Feeling of closeness by PHI correlated negatively with the role of leading by SOs (p > 0.001) and feeling of closeness by SOs was positively associated with leading by PHI (p = 0.015). No correlation was detected between nonverbal synchrony and other questionnaires. Burden experienced by the SOs was higher in SOs who reported less closeness (p = 0.014).

Discussion

A longer hearing impairment leads to more nonverbal leading by SOs compared to PHI with very short duration of hearing loss, possibly because of the long-lasting imbalance in communication. If PHI felt more closeness, SOs led less and vice versa. Burden experienced by SOs negatively correlated with closeness reported by SOs. Use of nonverbal signals and communication might help to improve benefits of auditory rehabilitation for PHI and decrease burden experienced by SOs.

Movement Synchrony Over Time: What Is in the Trajectory of Dyadic Interactions in Workplace Coaching?

Background

Coaching is increasingly viewed as a dyadic exchange of verbal and non-verbal interactions driving clients' progress. Yet, little is known about how the trajectory of dyadic interactions plays out in workplace coaching.

Method

This paper provides a multiple-step exploratory investigation of movement synchrony (MS) of dyads in workplace coaching. We analyzed a publicly available dataset of 173 video-taped dyads. Specifically, we averaged MS per session/dyad to explore the temporal patterns of MS across (a) the cluster of dyads that completed 10 sessions, and (b) a set of 173 dyadic interactions with a varied number of sessions. Additionally, we linked that pattern to several demographic predictors. The results indicate a differential downward trend of MS.

Results

Demographic factors do not predict best fitting MS curve types, and only client age and coach experience show a small but significant correlation.

Discussion

We provide contextualized interpretations of these findings and propose conceptual considerations and recommendations for future coaching process research and practice.

Exploring the "Dark Matter" of Social Interaction: Systematic Review of a Decade of Research in Spontaneous Interpersonal Coordination

Interpersonal coordination is a research topic that has attracted considerable attention this last decade both due to a theoretical shift from intra-individual to inter-individual processes and due to the development of new methods for recording and analyzing movements in ecological settings. Encompassing spatiotemporal behavioral matching, interpersonal coordination is considered as "social glue" due to its capacity to foster social bonding. However, the mechanisms underlying this effect are still unclear and recent findings suggest a complex picture. Goal-oriented joint action and spontaneous coordination are often conflated, making it difficult to disentangle the role of joint commitment from unconscious mutual attunement. Consequently, the goals of the present article are twofold: (1) to illustrate the rapid expansion of interpersonal coordination as a research topic and (2) to conduct a systematic review of spontaneous interpersonal coordination, summarizing its latest developments and current challenges this last decade. By applying Rapid Automatic Keyword Extraction and Latent Dirichlet Allocation algorithms, keywords were extracted from PubMed and Scopus databases revealing the large diversity of research topics associated with spontaneous interpersonal coordination. Using the same databases and the keywords "behavioral matching," "interactional synchrony," and "interpersonal coordination," 1,213 articles were identified, extracted, and screened following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses protocol. A total of 19 articles were selected using the following inclusion criteria: (1) dynamic and spontaneous interactions between two unacquainted individuals (2) kinematic analyses, and (3) non-clinical and non-expert adult populations. The results of this systematic review stress the proliferation of various definitions and experimental paradigms that study perceptual and/or social influences on the emergence of spontaneous interpersonal coordination. As methods and indices used to quantify interpersonal coordination differ from one study to another, it becomes difficult to establish a coherent picture. This review highlights the need to reconsider interpersonal coordination not as the pinnacle of social interactions but as a complex dynamical process that requires cautious interpretation. An interdisciplinary approach is necessary for building bridges across scattered research fields through opening a dialogue between different theoretical frameworks and consequently provides a more ecological and holistic understanding of human social cognition.

Change Process in Coaching: Interplay of Nonverbal Synchrony, Working Alliance, Self-Regulation, and Goal Attainment

Background: Psychological literature emphasizes that self-regulation is important as goal intentions, goal setting, or implementation intention does not automatically result in effective results in coaching. The question which coaching strategies to apply to strengthening clients' self-regulatory capacities as prerequisites of effective change outcomes remains a black box in coaching.

Method: This quantitative study explored clients' self-regulatory mechanisms by addressing how nonverbal synchrony influences clients' cognitive and emotional self-regulation across sessions. One hundred eighty-four coach–client pairs and their evolving change process were observed over 8 months. Video-recorded sessions were assessed with motion energy analysis to automatically capture coach and client nonverbal behavior and quantify nonverbal synchrony at the level of the dyad.

Results: Synchrony was differentially associated with clients' post-session questionnaires on result-oriented problem-reflection and self-reflection, affect balance, and working alliance. Network analyses suggested that the association between synchrony and other process variables did not correspond to the previously found positive association between synchrony and positive aspects of alliance or outcome. Instead, this association depended on the level of perceived outcome.

Discussion: Coaching success may be predicted by process variables assessed after each session: goal reflection, alliance, and mood all predict successful coaching. The assessment of nonverbal synchrony suggests a state-dependent effect of embodied processes on a coaching outcome that warrants further inspection.

Video-based tracking approach for nonverbal synchrony: A comparison of Motion Energy Analysis and OpenPose

The present study investigated the comparability of two video-based tracking techniques, namely, Motion Energy Analysis and OpenPose, in the context of nonverbal synchrony research. Participants aged 23-69 years held a 15-min unstructured conversation with a same-gender partner of the same generation. Each participant's movements were quantified with two algorithms, which were separately submitted to a wavelet transform to assess synchrony between the partners. Wavelet coherence and information in the relative phase were used to measure the intensities and patterns of synchrony, respectively. As a benchmark of the test results, gender effects and correlation with the Big Five personality traits were examined. Irrespective of the tracking technique used, the results consistently illustrated gender effects: female dyads showed more synchrony than male dyads. Among the Big Five personality traits, only Extraversion was significantly associated with synchrony in either tracking technique. The gender effect remained significant in both the tracking techniques even when controlling for personality traits, indicating that both individual (i.e., personality) and social (i.e., gender) factors contribute to synchrony. The use of video-tracking techniques in the research on synchrony for future studies was also discussed.