Hyperscanning Research Papers - Academia.edu (original) (raw)

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... more

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.

Music played in ensembles is a naturalistic model to study joint action and leader- follower relationships. Recently, the investigation of the brain underpinnings of joint musical actions has gained attention; however, the cerebral... more

Music played in ensembles is a naturalistic model to study joint action and leader- follower relationships. Recently, the investigation of the brain underpinnings of joint musical actions has gained attention; however, the cerebral correlates underlying the roles of leader and follower in music performance remain elusive. The present study addressed this question by simultaneously measuring the hemodynamic correlates of functional neural activity elicited during naturalistic violin duet performance using fNIRS. Findings revealed distinct patterns of functional brain activation when musicians played the Violin 2 (follower) than the Violin 1 part (leader) in duets, both compared to solo performance. More specifically, results indicated that musicians playing the Violin 2 part had greater oxy-Hb activation in temporo-parietal (p = 0.02) and somatomotor (p = 0.04) regions during the duo condition in relation to the solo. On the other hand, there were no significant differences in the activation of these areas between duo/solo conditions during the execution of the Violin 1 part (p’s > 0.05). These findings suggest that ensemble cohesion during a musical performance may impose particular demands when musicians play the follower position, especially in brain areas associated with the processing of dynamic social information and motor simulation. This study is the first to use fNIRS hyperscanning technology to simultaneously measure the brain activity of two musicians during naturalistic music ensemble performance, opening new avenues for the investigation of brain correlates underlying joint musical actions with multiple subjects in a naturalistic environment.

The mechanisms underlying analgesia related to social touch are not clear. While recent research highlights the role of the empathy of the observer to pain relief in the target, the contribution of social interaction to analgesia is... more

The mechanisms underlying analgesia related to social touch are not clear. While recent research highlights the role of the empathy of the observer to pain relief in the target, the contribution of social interaction to analgesia is unknown. The current study examines brain-to-brain coupling during pain with interpersonal touch and tests the involvement of interbrain synchrony in pain alleviation. Romantic partners were assigned the roles of target (pain receiver) and observer (pain observer) under pain–no-pain and touch–no-touch conditions concurrent with EEG recording. Brain-to-brain coupling in alpha–mu band (8–12 Hz) was estimated by a three-step multilevel analysis procedure based on running window circular correlation coefficient and post hoc power of the findings was calculated using simulations. Our findings indicate that hand-holding during pain administration increases brain-to-brain coupling in a network that mainly involves the central regions of the pain target and the right hemisphere of the pain observer. Moreover, brain-to-brain coupling in this network was found to correlate with analgesia magnitude and observer’s empathic accuracy. These findings indicate that brain-to-brain coupling may be involved in touch-related analgesia.

Mental health problems remain among the main generators of costs within and beyond the health care system. Psychotherapy, the tool of choice in their treatment, is qualified by social interaction, and cooperation within the... more

Mental health problems remain among the main generators of costs within and beyond the health care system. Psychotherapy, the tool of choice in their treatment, is qualified by social interaction, and cooperation within the therapist-patient-dyad. Research into the factors influencing therapy success to date is neither exhaustive nor conclusive. Among many others, the quality of the relationship between therapist and patient stands out regardless of the followed psychotherapy school. Emerging research points to a connection between interpersonal synchronization within the sessions and therapy outcome. Consequently, it can be considered significant for the shaping of this relationship. The framework of Embodied Cognition assumes bodily and neuronal correlates of thinking. Therefore, the present paper reviews investigations on interpersonal, non-verbal synchrony in two domains: firstly, studies on interpersonal synchrony in psychotherapy are reviewed (synchronization of movement). Secondly, findings on neurological correlates of interpersonal synchrony (assessed with EEG, fMRI, fNIRS) are summarized in a narrative manner. In addition, the question is asked whether interpersonal synchrony can be achieved voluntarily on an individual level. It is concluded that there might be mechanisms which could give more insights into therapy success, but as of yet remain uninvestigated. Further, the framework of embodied cognition applies more to the current body of evidence than classical cognitivist views. Nevertheless, deeper research into interpersonal physical and neurological processes utilizing the framework of Embodied Cognition emerges as a possible route of investigation on the road to lower drop-out rates, improved and quality-controlled therapeutic interventions, thereby significantly reducing healthcare costs.

Cognition involving others, or social cognition, is often conceptualized as the soli- tary, third-person computation of mental states. Relatively, little attention has been paid to how individuals use their cognitive capacities at the... more

Cognition involving others, or social cognition, is often conceptualized as the soli- tary, third-person computation of mental states. Relatively, little attention has been paid to how individuals use their cognitive capacities at the behavioral and brain levels in social exchanges. We introduce imitation as a valuable model of dynamic social interactive phenomena and describe laboratory procedures for studying it in behavioral and neuroimaging contexts. We review research that reveals behavioral and neural synchronization of individuals engaged in imitation. In the latter case, brain activity is correlated in imitative partners, but the pattern expressed by an individual depends on the individual’s role (i.e., model or imitator). We link these find- ings to theoretical notions about mirroring and mentalizing brain systems and then describe how mirroring and mentalizing support the notion of prospective cognition, even in basic forms of communication such as reciprocal imitation.

Much evidence suggests that dynamic laws of neurobehavioral coordination are sui generis: they deal with collective properties that are repeatable from one system to another and emerge from microscopic dynamics but may not (even in... more

Much evidence suggests that dynamic laws of neurobehavioral coordination are sui generis: they deal with collective properties that are repeatable from one system to another and emerge from microscopic dynamics but may not (even in principle) be deducible from them. Nevertheless, it is useful to try to understand the relationship between different levels while all the time respecting the autonomy of each. We report a program of research that uses the theoretical concepts of coordination dynamics and quantitative measurements of simple, well-defined experimental model systems to explicitly relate neural and behavioral levels of description in human beings. Our approach is both top-down and bottom-up and aims at ending up in the same place: top-down to derive behavioral patterns from neural fields, and bottom-up to generate neural field patterns from bidirectional coupling between astrocytes and neurons. Much progress can be made by recognizing that the two approaches–reductionism and emergentism–are complementary. A key to understanding is to couch the coordination of very different things–from molecules to thoughts–in the common language of coordination dynamics.

Recently, the neuroscience field took a particular interest in the use of a neuroimaging technique called ‘hyperscanning’. This new technique consists in the simultaneous recording of the hemodynamic or neuroelectric activities of... more

Recently, the neuroscience field took a particular interest in the use of a neuroimaging technique called ‘hyperscanning’. This new technique consists in the simultaneous recording of the hemodynamic or neuroelectric activities of multiple subjects. Behind this small technical step lays a giant methodological leap. Groundbreaking insight in the understanding of social cognition shall be achieved if the right paradigms are implemented. A growing number of studies demonstrate the potential of this recent technique. In this paper, we will focus on current issues and future perspectives of brain studies using hyperscanning. We will also add to this review two studies initiated by Line Garnero. These studies will illustrate the promising possibilities offered by hyperscanning through two different key phenomena pertaining to social interaction: gesture imitation and joint attention.

In competitive and cooperative scenarios, task difficulty should be dynamically adapted to suit people with different abilities. State-of-the-art difficulty adaptation methods for such scenarios are based on task performance, which... more

In competitive and cooperative scenarios, task difficulty should be dynamically adapted to suit people with different abilities. State-of-the-art difficulty adaptation methods for such scenarios are based on task performance, which conveys little information about user-specific factors such as workload. Thus, we present an exploratory study of automated affect recognition and task difficulty adaptation in a competitive scenario based on physiological linkage (covariation of participants’ physiological responses). Classification algorithms were developed in an open-loop study where 16 pairs played a competitive game while 5 physiological responses were measured: respiration, skin conductance, electrocardiogram, and 2 facial electromyograms. Physiological and performance data were used to classify four self-reported variables (enjoyment, valence, arousal, perceived difficulty) into two or three classes. The highest classification accuracies were obtained for perceived difficulty: 84.3% for two-class and 60.5% for three-class classification. As a proof of concept, the developed classifiers were used in a small closed-loop study to dynamically adapt game difficulty. While this closed-loop study found no clear advantages of physiology-based adaptation, it demonstrated the technical feasibility of such real-time adaptation. In the long term, physiology-based task adaptation could enhance competition and cooperation in many multi-user settings (e.g., education, manufacturing, exercise).

Physiological responses of two interacting individuals contain a wealth of information about the dyad: for example, the degree of engagement or trust. However, nearly all studies on dyadic physiological responses have targeted group-level... more

Physiological responses of two interacting individuals contain a wealth of information about the dyad: for example, the degree of engagement or trust. However, nearly all studies on dyadic physiological responses have targeted group-level analysis: e.g., correlating physiology and engagement in a large sample. Conversely, this paper presents a study where physiological measurements are combined with machine learning algorithms to dynamically estimate the engagement of individual dyads. Sixteen dyads completed 15-min naturalistic conversations and self-reported their engagement on a visual analog scale every 60 s. Four physiological signals (electrocardiography, skin conductance, respiration, skin temperature) were recorded, and both individual physiological features (e.g., each participant’s heart rate) and synchrony features (indicating degree of physiological similarity between two participants) were extracted. Multiple regression algorithms were used to estimate self-reported engagement based on physiological features using either leave-interval-out crossvalidation (training on 14 60-s intervals from a dyad and testing on the 15th interval from the same dyad) or leave-dyad-out crossvalidation (training on 15 dyads and testing on the 16th). In leave-interval-out crossvalidation, the regression algorithms achieved accuracy similar to a ‘baseline’ estimator that simply took the median engagement of the other 14 intervals. In leave-dyad-out crossvalidation, machine learning achieved a slightly higher accuracy than the baseline estimator and higher accuracy than an independent human observer. Secondary analyses showed that removing synchrony features and personality characteristics from the input dataset negatively impacted estimation accuracy and that engagement estimation error was correlated with personality traits. Results demonstrate the feasibility of dynamically estimating interpersonal engagement during naturalistic conversation using physiological measurements, which has potential applications in both conversation monitoring and conversation enhancement. However, as many of our estimation errors are difficult to contextualize, further work is needed to determine acceptable estimation accuracies.

Synchronous movement is a key component of social behavior in several species including humans. Recent theories have suggested a link between interpersonal synchrony of brain oscillations and interpersonal movement synchrony. The present... more

Synchronous movement is a key component of social behavior in several species including humans. Recent theories have suggested a link between interpersonal synchrony of brain oscillations and interpersonal movement synchrony. The present study investigated this link. Using transcranial alternating current stimulation (tACS) applied over the left motor cortex, we induced beta band (20 Hz) oscillations in pairs of individuals who both performed a finger-tapping task with the right hand. In-phase or anti-phase oscillations were delivered during a preparatory period prior to movement and while the tapping task was performed. In-phase 20 Hz stimulation enhanced interpersonal movement synchrony, compared with anti-phase or sham stimulation, particularly for the initial taps following the preparatory period. This was confirmed in an analysis comparing real vs pseudo pair surrogate data. No enhancement was observed for stimulation frequencies of 2 Hz (matching the target movement frequency) or 10 Hz (alpha band). Thus, phase-coupling of beta band neural oscillations across two individuals' (resting) motor cortices supports the interpersonal alignment of sensorimotor processes that regulate rhythmic action initiation, thereby facilitating the establishment of synchronous movement. Phase-locked dual brain stimulation provides a promising method to study causal effects of interpersonal brain synchrony on social, sensorimotor and cognitive processes.

Recent advances in brain sciences have enabled the co-recording of multiple interacting brains (i.e., hyperscanning [1]). This technique has led to the discovery of inter-brain synchrony (IBS) between people involved in social and... more

Recent advances in brain sciences have enabled the co-recording of multiple interacting brains (i.e., hyperscanning [1]). This technique has led to the discovery of inter-brain synchrony (IBS) between people involved in social and interactive scenarios. In a recent article, Novembre and Iannetti argued that studies using hyperscanning to understand social behaviors are crucial but limited to correlational analysis [2]. They further developed the idea that the causal role of IBS can only be apprehended through multi-brain stimulation (MBS). Although we agree with Novembre and Iannetti that MBS is one of the most promising methods for investigating inter-brain coupling in the future, we disagree on their radical claim that it constitutes ‘the only validated empirical approach capable of teasing apart the mechanistic from the epiphenomenal interpretation of inter-brain synchrony’. In this Letter, we defend the idea that explaining IBS in terms of causal mechanisms is possible through adequate experimental designs and computational tools, with empirical approaches ranging from multi-brains (hyperscanning) to single-brain (classic social neuroscience) recordings, and even no-brain (i.e., in silico computational social neuroscience).

See society for neuroscience abstract at sfn.org

Brain correlates of the sense of agency have recently received increased attention. However, the explorations remain largely restricted to the study of brains in isolation. The prototypical paradigm used so far consists of manipulating... more

Brain correlates of the sense of agency have recently received increased attention. However, the explorations remain largely restricted to the study of brains in isolation. The prototypical paradigm used so far consists of manipulating visual perception of own action while asking the subject to draw a distinction between self- versus externally caused action. However, the recent definition of agency as a multifactorial phenomenon combining bottom-up and top-down processes suggests the exploration of more complex situations. Notably there is a need of accounting for the dynamics of agency in a two-body context where we often experience the double faceted question of who is at the origin of what in an ongoing interaction. In a dyadic context of role switching indeed, each partner can feel body ownership, share a sense of agency and altogether alternate an ascription of the primacy of action to self and to other. To explore the brain correlates of these different aspects of agency, we recorded with dual EEG and video set-ups 22 subjects interacting via spontaneous versus induced imitation (II) of hand movements. The differences between the two conditions lie in the fact that the roles are either externally attributed (induced condition) or result from a negotiation between subjects (spontaneous condition). Results demonstrate dissociations between self- and other-ascription of action primacy in delta, alpha and beta frequency bands during the condition of II. By contrast a similar increase in the low gamma frequency band (38–47 Hz) was observed over the centro-parietal regions for the two roles in spontaneous imitation (SI). Taken together, the results highlight the different brain correlates of agency at play during live interactions.

The bulk of social neuroscience takes a ‘stimulus-brain’ approach, typically comparing brain responses to different types of social stimuli, but most of the time in the absence of direct social interaction. Over the last two decades, a... more

The bulk of social neuroscience takes a ‘stimulus-brain’ approach, typically comparing brain responses to different types of social stimuli, but most of the time in the absence of direct social interaction. Over the last two decades, a growing number of researchers have adopted a ‘brain-to-brain’ approach, exploring similarities between brain patterns across participants as a novel way to gain insight into the social brain. This methodological shift has facilitated the introduction of naturalistic social stimuli into the study design (e.g., movies), and, crucially, has spurred the development of new tools to directly study social interaction, both in controlled experimental settings and in more ecologically valid environments. Specifically, hyperscanning setups, which allow the simultaneous recording of brain activity from two or more individuals during social tasks has gained popularity in recent years. However, currently there is no agreed-upon approach to carry out such inter-brain connectivity analysis, resulting in a scattered landscape of analysis techniques. To accommodate a growing demand to standardize analysis approaches in this fast-growing research field, we have developed HyPyP, a comprehensive and easy open-source software package that allows (social) neuroscientists to carry-out and to interpret inter-brain connectivity analyses.

While previous studies separately demonstrate EEG spectral modulations during speech preparation and ERP responses to the listened speech, it is unclear whether these responses are related on a trial-by-trial basis between a speaker and... more

While previous studies separately demonstrate EEG spectral modulations during speech preparation and ERP responses to the listened speech, it is unclear whether these responses are related on a trial-by-trial basis between a speaker and listener. In order to determine whether these responses are related in real-time, Electroencephalography (EEG) responses were measured simultaneously within a speaker and listener using a 24 electrode Mobile EEG system (18 participants; 9 pairs) during a sentence completion task. Each trial consisted of a sentence prompt with an incomplete ending (e.g. " I took my dog for a ____ "). The speaker was instructed to fill in the ending with something expected (e.g. " walk ") (40 trials) or unexpected (e.g. " drink ") (40 trials). The other participant listened to the speaker throughout the block. We found that lower alpha band activity was reduced when individuals prepared unexpected sentence endings compared to expected sentence endings. Greater reductions in the speaker's lower alpha activity during response preparation were correlated with a more negative N400 response in the listener to the unexpected word. These findings demonstrate that alpha suppression and the N400 ERP effect are present within a hyperscanning context and they are correlated between the speaker and listener during sentence completion. During communication, the speaker is tasked with generating a sequence of words which are semantically logical and which follow syntactic structure. The listener is tasked with incorporating the pragmatics, prosody, semantics and syntax of the listened speech into meaning 1. In order to accomplish these tasks, the listener appears to track these speech features, generate predictions for upcoming speech, and engage in further processing when predictions are violated 2–5. These aspects of speech processing are likely supported by the series of cortical oscillatory and event-related potential (ERP) responses that appear during speech, illuminating the neural mechanisms that likely support speech and language comprehension. The most prominent language-related ERP peaks occur approximately 200 ms, 400 ms, and 600 ms following the onset of speech violations. The early negative peak at ~200 ms appears to correspond to instances where the earliest phonological unit does not align with the phonological unit that is expected 6,7. The negative peak at 400 ms, termed the N400, appears sensitive to violations of the expected semantic meaning of a word (given the preceding context) 1,8 , and the positive peak at 600 ms (termed the P600) is primarily modulated by violations in syntax (i.e. grammatical structure) 9. Importantly, the N400 shows a graded variation in response amplitude as a function of the surprise of unexpected words 2,8,10 , and areas involved in the N400 appear sensitive to the degree in which verbs constrain subsequent nouns (e.g. a greater response to the verb " drive " , which predicts " car " , than to the verb " get " which is less predictive of the noun that will follow) 5. The N400 thus appears to index semantic prediction, consistent with predictive coding theories which posit that higher order contextual areas transfer predictions to early sensory areas in anticipation of incoming sensory stimuli 4,11,12. The P600, in contrast, does not appear to be modulated by predictive processes directly, but instead appears to reflect repair processes that follow syntactic violations 13,14. An important factor that may mediate the presence and magnitude of these ERP components is the complexity of the speech stimulus and the larger social context. For example, the presence of the N200 and the latency

Recent development in diffusion spectrum brain imaging combined to functional simulation has the potential to further our understanding of how structure and dynamics are intertwined in the human brain. At the intra-individual scale,... more

Recent development in diffusion spectrum brain imaging combined to functional simulation has the potential to further our understanding of how structure and dynamics are intertwined in the human brain. At the intra-individual scale, neurocomputational models have already started to uncover how the human connectome constrains the coordination of brain activity across distributed brain regions. In parallel, at the inter-individual scale, nascent social neuroscience provides a new dynamical vista of the coupling between two embodied cognitive agents. Using EEG hyperscanning to record simultaneously the brain activities of subjects during their ongoing interaction, we have previously demonstrated that behavioral synchrony correlates with the emergence of inter-brain synchronization. However, the functional meaning of such synchronization remains to be specified. Here, we use a biophysical model to quantify to what extent inter-brain synchronizations are related to the anatomical and functional similarity of the two brains in interaction. Pairs of interacting brains were numerically simulated and compared to real data. Results show a potential dynamical property of the human connectome to facilitate inter-individual synchronizations and thus may partly account for our propensity to generate dynamical couplings with others.

The mechanisms underlying analgesia related to social touch are not clear. While recent research highlights the role of the empathy of the observer to pain relief in the target, the contribution of social interaction to analgesia is... more

The mechanisms underlying analgesia related to social touch are not clear. While recent research highlights the role of the empathy of the observer to pain relief in the target, the contribution of social interaction to analgesia is unknown. The current study examines brain-to-brain coupling during pain with interpersonal touch and tests the involvement of interbrain synchrony in pain alleviation. Romantic partners were assigned the roles of target (pain receiver) and observer (pain observer) under pain-no-pain and touch-no-touch conditions concurrent with EEG recording. Brain-to-brain coupling in alpha-mu band (8-12 Hz) was estimated by a three-step multilevel analysis procedure based on running window circular correlation coefficient and post hoc power of the findings was calculated using simulations. Our findings indicate that hand-holding during pain administration increases brain-to-brain coupling in a network that mainly involves the central regions of the pain target and the ...

The human brain has undergone massive expansion across primate evolution through life amidst multi-layered social attachments; within families, among friends, and between clan members and this enabled humans to coordinate their brains... more

The human brain has undergone massive expansion across primate evolution through life amidst multi-layered social attachments; within families, among friends, and between clan members and this enabled humans to coordinate their brains with those of others toward the execution of complex social goals. We examined how human attachments facilitate efficient, resource-sensitive performance of social goals by balancing neural and behavioral synchrony. Using hyperscanning EEG, we collected neural data from male-female pairs in three groups (N = 158, 79 pairs); long-term couples, best friends, and unfamiliar group members, during two ecologically-valid natural-istic tasks; motor coordination and empathy giving. Across groups and tasks, neural synchrony was supported by behavior coordination and orchestrated multiple neural rhythms. In the goal-directed motor task, interbrain syn-chrony implicated beta and gamma rhythms localized to sensorimotor areas. Couples showed the highest neural synchrony combined with greatest behavioral synchrony and such brain-behavior linkage resulted in speedy performance , conserving energy in the long run. The socially-oriented empathy task triggered neural synchrony in widely-distributed sensorimotor and bilateral temporal regions, integrated alpha, beta, and gamma rhythms, and implicated brain-behavior complementarity ; couples displayed the highest behavioral synchrony combined with lowest neural synchrony toward greatest felt support while strangers exhibited the opposite pattern. Findings suggest that human attachments provide a familiar backdrop of temporal regularities, required for the brain's allostatic function, and interbrain and behavioral synchrony are sculpted by familiarity and closeness toward resource-sensitive performance of survival-related social goals, toiled by two.

The current study explored interbrain neural coupling when interlocutors engage in a conversation–like situation using different languages known to them. To this end, electroencephalographic hyperscanning was used to study brain-to-brain... more

The current study explored interbrain neural coupling when interlocutors engage in a conversation–like situation using different languages known to them. To this end, electroencephalographic hyperscanning was used to study brain-to-brain phase synchronization during a two-person turn-taking verbal exchange in either a native or a fluent nonnative (foreign) language context. Results show that the coupling strength between brain signals in the alpha frequency band was increased for both language contexts. Electrode-pairs containing significant effects were broadly distributed across the scalp of the listener and speaker: Five electrodes show a larger synchronization in the native language context (Spanish), and nine in the foreign language context (English). These results indicate that between brain similarities in the timing of neural activations and their spatial distributions change depending on the language code used. We suggest that factors like linguistic alignment, joint attention and brain-entrainment to speech operate with a language-idiosyncratic neural configuration, modulating the alignment of neural activity between speakers and listeners. We concluded that linguistic context should be considered when addressing interpersonal communication. The findings here open doors to quantifying linguistic interactions.

Much of human learning emerges as a result of interaction with others. Yet, this interpersonal process has been poorly characterized from a neurophysiological perspective. This study investigated (i) whether Interpersonal Brain... more

Much of human learning emerges as a result of interaction with others. Yet, this interpersonal process has been poorly characterized from a neurophysiological perspective. This study investigated (i) whether Interpersonal Brain Synchronization (IBS) can reliably mark social interactive learning, and specifically (ii) during what kind of interactive behavior. We recorded brain activity from learner-instructor dyads using functional Near-Infrared Spectroscopy (fNIRS) during the acquisition of a music song. We made four fundamental observations. First, during the interactive learning task, brain activity recorded from the bilateral Inferior Frontal Cortex (IFC) synchronized across the learner and the instructor. Second, such IBS was observed in particular when the learner was observing the instructor's vocal behavior and when the learning experience entailed a turn-taking and more active mode of interaction. Third, this specific enhancement of IBS predicted learner's behavioral performance. Fourth, Granger causality analyses further disclosed that the signal recorded from the instructor's brain better predicted that recorded from the learner's brain than vice versa. Together, these results indicate that social interactive learning can be neurophysiologically characterized in terms of IBS. Furthermore, they suggest that the learner's involvement in the learning experience, alongside the instructor's modeling, are key factors driving the alignment of neural processes across learner and instructor. Such alignment impacts upon the real-time acquisition of new information and eventually upon the learning (behavioral) performance. Hence, besides providing a biological characterization of social interactive learning, our results hold relevance for clinical and pedagogical practices.

Social neuroscience shows a growing interest for the study of social interaction. Investigating its neural underpinnings has been greatly facilitated through the development of hyperscanning, a neuroimaging technique allowing to record... more

Social neuroscience shows a growing interest for the study of social interaction. Investigating its neural underpinnings has been greatly facilitated through the development of hyperscanning, a neuroimaging technique allowing to record simultaneously the brain activity of multiple humans engaged in a social exchange. However, the analysis of spontaneous social interaction requires the indexing of the ongoing behavior. Since spontaneous exchanges are intrinsically unconstrained, only a manual indexing by frame-by-frame analysis has been used so far. Here we present an automatic measure of imitation during spontaneous social interaction. Participants gestures are caracterized with Bag of Words and 1-class SVM models. Then a measure of imitation is derived from the likelihood ratio between these models. We apply this method to hyperscanning EEG recordings of spontaneous imitation of bimanual hand movements. The comparison with manual indexing validates the method at both behavioral and neural levels, demonstrating its ability to discriminate significantly the periods of imitation and non-imitation during social interaction.

How are neural, behavioral and social scales coordinated in real time so as to make possible the emergence of social cognition? Answering this question requires to study the dynamics of coordination in real human interactions. However,... more

How are neural, behavioral and social scales coordinated in real time so as to make possible the emergence of social cognition? Answering this question requires to study the dynamics of coordination in real human interactions. However, even at the simplest dyadic scale, methodological and theoretical challenges remain. Several theories have been proposed to infer the link between neurobiology and social psychology, but the dynamical components of human interaction are still poorly explored because of the difficulty to record simultaneously the brain activity from several subjects. This is the goal of hyperscanning methodology. I will first present how the combination of situated social paradigms with hyperscanning allowed to demonstrate that states of interactional synchrony at the behavioral level correlate with the emergence of inter-individual synchronization at the brain level (Dumas et al. PLoS ONE 2010). It thus demonstrated for the first time anatomo-functional similarities between two human brains at the millisecond level, without any common external driving signal. The related inter-brain synchronization in different frequency bands appeared to reflect different aspects of social interaction, such as interactional synchrony, anticipation of other's actions and co-regulation of turn-taking. Then, I will present how such phenomena can be simulated with biologically inspired numerical simulations (e.g. using direct measures of brain connectivity with DTI) and how the human connectome facilitates inter-individual synchronizations and thus may partly account for our propensity to generate dynamical couplings with others (Dumas et al. PLoS ONE 2012). Finally, I will present another tool called Virtual Partner Interaction (VPI) (Kelso, et al. PLoS ONE 2009). This VPI integrates equations of human motion at the neurobehavioral level. A human and a "virtual partner" are then reciprocally coupled in real-time, which allow controlling the dynamical parameters of the interaction while maintaining the continuous flow of interaction. This technique scaled up to the level of human behavior the idea of dynamic clamps used to study the dynamics of interactions between neurons. By combining studies on both human-human and human-machine interactions thus present new approaches for investigating the neurobiological mechanisms of interpersonal coordination, and test theoretical/computational models concerning the dynamics at the neural, behavioral and social scales.