Brain-to-Brain Synchrony during Naturalistic Social Interactions (original) (raw)
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Inter-Brain Synchronization during Social Interaction
During social interaction, both participants are continuously active, each modifying their own actions in response to the continuously changing actions of the partner. This continuous mutual adaptation results in interactional synchrony to which both members contribute. Freely exchanging the role of imitator and model is a well-framed example of interactional synchrony resulting from a mutual behavioral negotiation. How the participants' brain activity underlies this process is currently a question that hyperscanning recordings allow us to explore. In particular, it remains largely unknown to what extent oscillatory synchronization could emerge between two brains during social interaction. To explore this issue, 18 participants paired as 9 dyads were recorded with dual-video and dual-EEG setups while they were engaged in spontaneous imitation of hand movements. We measured interactional synchrony and the turn-taking between model and imitator. We discovered by the use of nonlinear techniques that states of interactional synchrony correlate with the emergence of an interbrain synchronizing network in the alpha-mu band between the right centroparietal regions. These regions have been suggested to play a pivotal role in social interaction. Here, they acted symmetrically as key functional hubs in the interindividual brainweb. Additionally, neural synchronization became asymmetrical in the higher frequency bands possibly reflecting a top-down modulation of the roles of model and imitator in the ongoing interaction.
Social synchronization of brain activity increases during eye-contact
Communications biology, 2022
Humans make eye-contact to extract information about other people's mental states, recruiting dedicated brain networks that process information about the self and others. Recent studies show that eye-contact increases the synchronization between two brains but do not consider its effects on activity within single brains. Here we investigate how eyecontact affects the frequency and direction of the synchronization within and between two brains and the corresponding network characteristics. We also evaluate the functional relevance of eye-contact networks by comparing inter-and intra-brain networks of friends vs. strangers and the direction of synchronization between leaders and followers. We show that eye-contact increases higher inter-and intra-brain synchronization in the gamma frequency band. Network analysis reveals that some brain areas serve as hubs linking within-and between-brain networks. During eye-contact, friends show higher inter-brain synchronization than strangers. Dyads with clear leader/follower roles demonstrate higher synchronization from leader to follower in the alpha frequency band. Importantly, eye-contact affects synchronization between brains more than within brains, demonstrating that eye-contact is an inherently social signal. Future work should elucidate the causal mechanisms behind eyecontact induced synchronization.
You are in sync with me: neural correlates of interpersonal synchrony with a partner
Neuroscience, 2014
Interpersonal synchrony is characterized by a temporary alignment of periodic behaviors with another person. This process requires that at least one of the two individuals monitors and adjusts his/her movements to maintain alignment with the other individual (the referent). Interestingly, recent research on interpersonal synchrony has found that people who are motivated to befriend an unfamiliar social referent tend to automatically synchronize with their social referents, raising the possibility that synchrony may be employed as an affiliation tool. It is unknown, however, whether the opposite is true; that is, whether the person serving as the referent of interpersonal synchrony perceives synchrony with his/her partner or experiences affiliative feelings toward the partner. To address this question, we performed a series of studies on interpersonal synchrony with a total of 100 participants. In all studies, participants served as the referent with no requirement to monitor or alig...
Social synchronisation of brain activity by eye-contact
2021
Humans make eye-contact to extract information about other people’s mental states, recruiting dedicated brain networks that process information about the self and others. Recent studies show that eye-contact increases the synchronization between two brains. We investigated how eye-contact affects the frequency and direction of the synchronization within and between brains and the characteristics of the dual brain network (i.e. hyperbrain). Eye-contact was associated with higher coherence in the gamma frequency band (30-45Hz) for between and within brain connections. Network analysis revealed that some brain areas served as hubs which linked within- and between- brain networks (midparietal, midfrontal and right parietal areas). Friends showed more efficient eye-contact hyperbrain networks than strangers. During eye-contact, some dyads spontaneously adopted leader/follower roles, resulting in an increase in synchronization from leader to follower (interbrain) in the alpha frequency ba...
Functional dissociation of brain rhythms in social coordination
2012
h i g h l i g h t s Spectral separation of sub-bands in the mu domain was used to identify neural processes in tasks requiring real-time social interaction: changes in the lower mu band were diffuse and non-specific; changes in the upper mu band were highly related to coupling measures of intentional social coordination. In the upper mu-band event-related synchronization was associated with uncoupled behavior whereas event-related de-synchronization denoted coupled behaviors.
Human Brain Mapping
In social interactions, each individual's brain drives an action that, in turn, elicits systematic neural responses in their partner that drive a reaction. Consequently, the brain responses of both interactants become temporally contingent upon one another through the actions they generate, and different interaction dynamics will be underpinned by distinct forms of between-brain coupling. In this study, we investigated this by "performing functional magnetic resonance imaging on two individuals simultaneously (dual-fMRI) while they competed or cooperated with one another in a turn-based or concurrent fashion." To assess whether distinct patterns of neural coupling were associated with these different interactions, we combined two data-driven, model-free analytical techniques: group-independent component analysis and inter-subject correlation. This revealed four distinct patterns of brain responses that were temporally aligned between interactants: one emerged during cooperative exchanges and encompassed brain regions involved in social cognitive processing, such as the temporo-parietal cortex. The other three were associated with competitive exchanges and comprised brain systems implicated in visuomotor processing and social decision-making, including the cerebellum and anterior cingulate cortex. Interestingly, neural coupling was significantly stronger in concurrent relative to turn-based exchanges. These results demonstrate the utility of data-driven approaches applied to "dual-fMRI" data in elucidating the interpersonal neural processes that give rise to the two-in-one dynamic characterizing social interaction.
Interpersonal body and neuralsynchronization as a marker of implicitsocial interaction
One may have experienced his or her footsteps unconsciously synchronize with the footsteps of a friend while walking together, or heard an audience's clapping hands naturally synchronize into a steady rhythm. However, the mechanisms of body movement synchrony and the role of this phenomenon in implicit interpersonal interactions remain unclear. We aimed to evaluate unconscious body movement synchrony changes as an index of implicit interpersonal interaction between the participants, and also to assess the underlying neural correlates and functional connectivity among and within the brain regions. We found that synchrony of both fingertip movement and neural activity between the two participants increased after cooperative interaction. These results suggest that the increase of interpersonal body movement synchrony via interpersonal interaction can be a measurable basis of implicit social interaction. The paradigm provides a tool for identifying the behavioral and the neural correlates of implicit social interaction. S ynchronization is, in a broad sense, coordination of rhythmic oscillators due to their interaction. Interpersonal body movement synchronization has been widely observed. A person's footsteps unconsciously synchronize with those of a partner when two people are walking together, even though their foot lengths, and thus their intrinsic cycles, are different 1-3 . The phenomenon has been thought of as social selforganizing process 4 . Previous studies found that the degree of interpersonal body movement synchrony, such as finger tapping and drumming, predicted subsequent social ratings 5,6 . The findings indicate a close relationship between social interface and body movement synchronization 7 . However, the mechanism of body movement synchrony and its relationship to implicit interpersonal interaction remain vague.
Psychophysiological Synchrony During Verbal Interaction in Romantic Relationships
Family process, 2018
Previous studies about romantic relationships have shown that the reciprocal influence between partners occurs not only at the behavioral and socio-emotional levels, but also at the psychophysiological level. This reciprocal influence is expressed in a pattern of physiological synchrony between partners (i.e., coordinated dynamics of the physiological time series). The main aim of the present study was to explore the presence of a pattern of physiological synchrony in electrodermal activity (EDA) during a couple interaction task. A second objective was to compare the synchrony levels during a negative interaction condition versus a positive interaction condition. Finally, we analyzed the association between synchrony and self-perception of empathy, dyadic empathy, and relationship satisfaction. Thirty-two couples (64 individuals) participated in this study. Each couple performed a structured interaction task while the EDA of both partners was being registered. The quantification of ...
The mere co-presence of another person synchronizes physiological signals, but no study has systematically investigated effects of type of emotional context and type of relationship in eliciting dyadic physiological synchrony. In this study, we investigated the synchrony of pairs of strangers, companions, and romantic partners while watching a series of video clips designed to elicit different emotions. Maximal cross-correlation of heart rate variability (HRV) was used to quantify dyadic synchrony. The findings suggest that an existing social relationship might reduce the predisposition to conform one's autonomic responses to a friend or romantic partner during social situations that do not require direct interaction.