Building trust: Heart rate synchrony and arousal during joint action increased by public goods game

Inter-subject correlation of audience facial expressions predicts audience engagement during theatrical performances

During performances, audiences experience various emotional states, and these are reflected in their ongoing facial expressions. We investigated if audience engagement could be determined by measuring the inter-subject correlation (ISC) of non-invasively recorded audience facial expressions. We filmed the faces of multiple audience members at theatrical performances and determined the intensity of their different facial expressions throughout the performances. Neutral, happy, anger, and disgust expression ISCs accounted for up to 24% of the performance dramaturge's predictions of audience engagement. Expression synchrony was greater between individuals in close proximity, suggesting effects of emotional contagion or cognitive similarities between neighboring individuals, whereas expression synchrony was greatest between individuals who were younger, female, and with greater levels of empathy, showing that individual characteristics impact shared audience experiences. Together, our results show that facial expression synchronization could be used as a real-time non-invasive indicator of engagement in audiences larger than achieved using previous approaches.

Interpersonal heart rate synchrony predicts effective information processing in a naturalistic group decision-making task

Groups often outperform individuals in problem-solving. Nevertheless, failure to critically evaluate ideas risks suboptimal outcomes through so-called groupthink. Prior studies have shown that people who hold shared goals, perspectives, or understanding of the environment show similar patterns of brain activity, which itself can be enhanced by consensus-building discussions. Whether shared arousal alone can predict collective decision-making outcomes, however, remains unknown. To address this gap, we computed interpersonal heart rate synchrony, a peripheral index of shared arousal associated with joint attention, empathic accuracy, and group cohesion, in 44 groups (n = 204) performing a collective decision-making task. The task required critical examination of all available information to override inferior, default options and make the right choice. Using multidimensional recurrence quantification analysis (MdRQA) and machine learning, we found that heart rate synchrony predicted the probability of groups reaching the correct consensus decision with >70% cross-validation accuracy-significantly higher than that predicted by the duration of discussions, subjective assessment of team function or baseline heart rates alone. We propose that heart rate synchrony during group discussion provides a biomarker of interpersonal engagement that facilitates adaptive learning and effective information sharing during collective decision-making.

How and Why People Synchronize: An Integrated Perspective

Academic AbstractInterpersonal synchrony, the alignment of behavior and/or physiology during interactions, is a pervasive phenomenon observed in diverse social contexts. Here we synthesize across contexts and behaviors to classify the different forms and functions of synchrony. We provide a concise framework for classifying the manifold forms of synchrony along six dimensions: periodicity, discreteness, spatial similarity, directionality, leader-follower dynamics, and observability. We also distill the various proposed functions of interpersonal synchrony into four interconnected functions: reducing complexity and improving understanding, accomplishing joint tasks, strengthening social connection, and influencing partners' behavior. These functions derive from first principles, emerge from each other, and are accomplished by some forms of synchrony more than others. Effective synchrony flexibly adapts to social goals and more synchrony is not always better. Our synthesis offers a shared framework and language for the field, allowing for better cross-context and cross-behavior comparisons, generating new hypotheses, and highlighting future research directions.

Interpersonal heart rate synchrony predicts effective information processing in a naturalistic group decision-making task

Groups often outperform individuals in problem-solving. Nevertheless, failure to critically evaluate ideas risks sub-optimal outcomes through so-called groupthink. Prior studies have shown that people who hold shared goals, perspectives or understanding of the environment show similar patterns of brain activity, which itself can be enhanced by consensus building discussions. Whether shared arousal alone can predict collective decision-making outcomes, however, remains unknown. To address this gap, we computed interpersonal heart rate synchrony, a peripheral index of shared arousal associated with joint attention, empathic accuracy and group cohesion, in 44 groups (n=204) performing a collective decision-making task. The task required critical examination of all available information to override inferior, default options and make the right choice. Using multi-dimensional recurrence quantification analysis (MdRQA) and machine learning, we found that heart rate synchrony predicted the probability of groups reaching the correct consensus decision with greater than 70% cross-validation accuracy-significantly higher than that predicted by the duration of discussions, subjective assessment of team function or baseline heart rates alone. We propose that heart rate synchrony during group discussion provides a biomarker of interpersonal engagement that facilitates adaptive learning and effective information sharing during collective decision-making.

Emotion contagion and physiological synchrony: The more intimate relationships, the more contagion of positive emotions

The study aimed to explore how interpersonal closeness (friends vs. strangers) and emotion type (positive vs. negative) influenced emotion contagion and physiological synchrony between interacting partners. Twenty-eight friend dyads (n = 56) and 29 stranger dyads (n = 58) participated in an emotion contagion laboratory task. In each dyad, one participant, the 'sender', was randomly asked to watch a film clip (neutral, positive, or negative), while their partner, the 'observer' passively observed the sender's facial expressions. Participants' electrocardiograms (ECG) and facial electromyography (EMG) signals were recorded using the BIOPAC system. Results revealed that observing the sender's facial expressions led to the observer's spontaneous mimicry and emotional contagion, accompanied by enhanced physiological synchrony between interacting partners. In the positive emotion condition, the observers reported more positive emotions and displayed stronger zygomaticus major activity in friend dyads than in stranger dyads. Greater physiological synchrony (heart rate and heart rate variability) between interacting partners was also observed in friend dyads than in stranger dyads in the positive emotion condition. These results indicate that positive emotion contagion is more likely to occur between close partners than negative emotion contagion.

Susceptibility to peer influence in adolescents: Associations between psychophysiology and behavior

The current study investigated in-the-moment links between adolescents' autonomic nervous system activity and susceptibility to three types of peer influence (indirect, direct, continuing) on two types of behavior (antisocial, prosocial). The sample included 144 racially ethnically diverse adolescents (46% male, 53% female, 1% other; M age  = 16.02 years). We assessed susceptibility to peer influence behaviorally using the Public Goods Game (PGG) while measuring adolescents' mean heart rate (MHR) and pre-ejection period (PEP). Three key findings emerged from bivariate dual latent change score modeling: (1) adolescents whose MHR increased more as they transitioned from playing the PGG alone (pre-influence) to playing while simply observed by peers (indirect influence) displayed more prosocial behavior; (2) adolescents whose PEP activity increased more (greater PEP activity = shorter PEP latency) as they transitioned from indirect influence to being encouraged by peers to engage in antisocial behavior (direct influence) engaged in more antisocial behavior; and (3) adolescents whose PEP activity decreased less as they transitioned from direct influence on prosocial behavior to playing the PGG alone again (continuing influence) displayed more continuing prosocial behavior (marginal effect). The discussion focuses on the role of psychophysiology in understanding adolescents' susceptibility to peer influence.

Searching for the Metaverse: Neuroscience of Physical and Digital Communities

What distinguishes real-world communities from their online counterparts? Social and cognitive neuroscience research on social networks and collective intentionality will be used in the article to answer this question. Physical communities are born in places. And places engage "we-mode" neurobiological and cognitive processes as behavioral synchrony, shared attention, deliberate attunement, interbrain synchronization, and so on, which create coherent social networks of very different individuals who are supported by a "wisdom of crowd." Digital technologies remove physical boundaries, giving people more freedom to choose their activities and groups. At the same time, however, the lack of physical co-presence of community members significantly reduces their possibility of activating "we-mode" cognitive processes and social motivation. Because of this, unlike physical communities that allow interaction between people from varied origins and stories, digital communities are always made up of people who have the same interests and knowledge (communities of practice). This new situation disrupts the "wisdom of crowd," making the community more radical and less accurate (polarization effect), allowing influential users to wield disproportionate influence over the group's beliefs, and producing inequalities in the distribution of social capital. However, a new emergent technology-the Metaverse-has the potential to reverse this trend. Several studies have revealed that virtual and augmented reality-the major technologies underlying the Metaverse-can engage the same neurobiological and cognitive "we-mode" processes as real-world environments. If the many flaws in this technology are fixed, it might encourage people to engage in more meaningful and constructive interactions in online communities.

Understanding human encounters goes beyond explaining musculoskeletal coordination: a review

Complex systems theory has become one of the main frameworks to understand, model and explain interactional phenomena such as interpersonal coordination. In her paper, Butler (this issue) applies this approach to theorise about coordination at large, including human interactions. We argue that the all-encompassing language of complex systems theory leads to overemphasising the physical aspects that human interactions share with other coordinated systems in nature. This emphasis ultimately disregards the meaningful dimension implied in any human movement, understanding it as mechanical motion, rather than expressive actions.

Morality in the time of cognitive famine: The effects of memory load on cooperation and honesty

Though human social interaction in general seems effortless at times, successful engagement in collaborative or exploitative social interaction requires the availability of cognitive resources. Research on Dual-Process suggests that two systems, the affective (non-reflective) and the cognitive (reflective), are responsible for different types of reasoning. Nevertheless, the evidence on which system leads to what type of behavioral outcome, in terms of prosociality, is at best contradicting and perplexing. In the present paper, we examined the role of the two systems, operationalized as working memory depletion, in prosocial decision-making. We hypothesize that the nature of the available cognitive resources could affect whether humans engage in collaborative or exploitative social interaction. Using Operation Span to manipulate the availability of working memory, we examined how taxing the cognitive system affects cooperation and cheating. In two experiments, we provide evidence that concurrent load, but not cumulative load is detrimental to cooperation, whereas neither concurrent nor cumulative load seems to affect cheating behavior. These findings are in contrast to several previous assumptions. We discuss limitations, possible explanations, and future directions.

Identifying Signatures of Perceived Interpersonal Synchrony

Interpersonal synchrony serves as a subtle, yet powerful bonding mechanism in social interactions. Problematically, the term ‘synchrony’ has been used to label a variety of distinct aspects of interpersonal coordination, such as postural similarities or movement activity entrainment. Accordingly, different algorithms have been suggested to quantify interpersonal synchrony. Yet, it remains unknown whether the different measures of synchrony represent correlated features of the same perceivable core phenomenon. The current study addresses this by comparing the suitability of a set of algorithms with respect to their association with observers’ judgments of dyadic synchrony and leader-followership. One-hundred fifteen observers viewed computer animations of characters portraying the movements of real dyads who performed a repetitive motor task with instruction to move in unison. Animations were based on full-body motion capture data synchronously collected for both partners during the joint exercise. Results showed most synchrony measures significantly correlated with (a) perceived synchrony and (b) the perceived level of balance of leading/following by each dyad member. Phase synchrony and Pearson correlations were associated most strongly with the observer ratings. This might be typical for intentional, structured forms synchrony such as ritualized group activities. It remains open if these findings also apply to spontaneous forms of synchrony as, for instance, occurring in free-running conversations.

Trust Measurement in Human-Autonomy Teams: Development of a Conceptual Toolkit

The rise in artificial intelligence capabilities in autonomy-enabled systems and robotics has pushed research to address the unique nature of human-autonomy team collaboration. The goal of these advanced technologies is to enable rapid decision making, enhance situation awareness, promote shared understanding, and improve team dynamics. Simultaneously, use of these technologies is expected to reduce risk to those who collaborate with these systems. Yet, for appropriate human- autonomy teaming to take place, especially as we move beyond dyadic partnerships, proper calibration of team trust is needed to effectively coordinate interactions during high-risk operations. But to meet this end, critical measures of team trust for this new dynamic of human-autonomy teams are needed. This paper seeks to expand on trust measurement principles and the foundation of human-autonomy teaming to propose a “toolkit” of novel methods that support the development, maintenance and calibration of trust in human-autonomy teams operating within uncertain, risky, and dynamic environments.

Using Fitbit data to monitor the heart rate evolution patterns of college students

ObjectiveTo investigate what social, psychological, personality, and behavioral factors affect overtime heart rate changes of college students. Participants: The daily heart rates of over 600 undergraduates at the University of Notre Dame were unobtrusively recorded via Fitbit devices from August 16, 2015, to May 13, 2017. Method: Latent Growth-Curve modeling strategy is utilized to examine how daily mean heart rate and its standard deviation change over time, and what foregoing factors predict observed changes. Results: The mean heart rate increased and its standard deviation stayed the same over the 637 days. Heart rate levels go up with that of social contacts, an indicator of peer influence. Both daily heart rate levels and changes are also affected by multiple external factors. Conclusion: Human heart rate is not only a physiological phenomenon but also a social-psychological one, as it is systematically affected by peer networks, social contexts, and human activities.

Cognitive processing of a common stimulus synchronizes brains, hearts, and eyes

Neural, physiological, and behavioral signals synchronize between human subjects in a variety of settings. Multiple hypotheses have been proposed to explain this interpersonal synchrony, but there is no clarity under which conditions it arises, for which signals, or whether there is a common underlying mechanism. We hypothesized that cognitive processing of a shared stimulus is the source of synchrony between subjects, measured here as intersubject correlation (ISC). To test this, we presented informative videos to participants in an attentive and distracted condition and subsequently measured information recall. ISC was observed for electro-encephalography, gaze position, pupil size, and heart rate, but not respiration and head movements. The strength of correlation was co-modulated in the different signals, changed with attentional state, and predicted subsequent recall of information presented in the videos. There was robust within-subject coupling between brain, heart, and eyes, but not respiration or head movements. The results suggest that ISC is the result of effective cognitive processing, and thus emerges only for those signals that exhibit a robust brain-body connection. While physiological and behavioral fluctuations may be driven by multiple features of the stimulus, correlation with other individuals is co-modulated by the level of attentional engagement with the stimulus.

Multivariate model for cooperation: bridging social physiological compliance and hyperscanning

The neurophysiological analysis of cooperation has evolved over the past 20 years, moving towards the research of common patterns in neurophysiological signals of people interacting. Social physiological compliance (SPC) and hyperscanning represent two frameworks for the joint analysis of autonomic and brain signals, respectively. Each of the two approaches allows to know about a single layer of cooperation according to the nature of these signals: SPC provides information mainly related to emotions, and hyperscanning that related to cognitive aspects. In this work, after the analysis of the state of the art of SPC and hyperscanning, we explored the possibility to unify the two approaches creating a complete neurophysiological model for cooperation considering both affective and cognitive mechanisms We synchronously recorded electrodermal activity, cardiac and brain signals of 14 cooperative dyads. Time series from these signals were extracted, and multivariate Granger causality was computed. The results showed that only when subjects in a dyad cooperate there is a statistically significant causality between the multivariate variables representing each subject. Moreover, the entity of this statistical relationship correlates with the dyad’s performance. Finally, given the novelty of this approach and its exploratory nature, we provided its strengths and limitations.

Interpersonal physiological synchrony is associated with first person and third person subjective assessments of excitement during cooperative joint tasks

Interpersonal physiological synchrony has been shown to play important roles in social activities. While most studies have shed light on the effects of physiological synchrony on recognition of the group state, such as cohesion or togetherness, the effect of physiological synchrony on the recognition of emotional experience has not been adequately researched. In this study, we examined how physiological synchrony is associated with first- and third-person emotion recognition during a joint task. Two participants played a cooperative block-stacking game (Jenga), alternating their roles as player and adviser, while their heart rates were recorded. The participants evaluated their own emotional experience for each turn. Bystanders watched the game to evaluate the players' emotions. Results showed that the players' subjective excitement increased not only with their own heart rate, but also with increased heart rate synchrony with their adviser. Heart rate synchrony between player and adviser also related to increased intensity in perceived excitement from the bystanders. Given that both first- and third-person emotion recognition can have cumulative impacts on a group, the relationship between physiological synchrony and emotion recognition observed in the present study will help deepen understanding of the psychophysiological mechanisms underlying larger group phenomena such as crowd excitement.

Group-level physiological synchrony and individual-level anxiety predict positive affective behaviors during a group decision-making task

Joint performance can lead to the synchronization of physiological processes among group members during a shared task. Recently, it has been shown that synchronization is indicative of subjective ratings of group processes and task performance. However, different methods have been used to quantify synchronization, and little is known about the effects of the choice of method and level of analysis (individuals, dyads, or triads) on the results. In this study, participants performed a decision‐making task in groups of three while physiological signals (heart rate and electrodermal activity), positive affective behavior, and personality traits were measured. First, we investigated the effects of different levels of analysis of physiological synchrony on affective behavior. We computed synchrony measures as (a) individual contributions to group synchrony, (b) the average dyadic synchrony within a group, and (c) group‐level synchrony. Second, we assessed the association between physiological synchrony and positive affective behavior. Third, we investigated the moderating effects of trait anxiety and social phobia on behavior. We discovered that the effects of physiological synchrony on positive affective behavior were particularly strong at the group level but nonsignificant at the individual and dyadic levels. Moreover, we found that heart rate and electrodermal synchronization showed opposite effects on group members' display of affective behavior. Finally, trait anxiety moderated the relationship between physiological synchrony and affective behavior, perhaps due to social uncertainty, while social phobia did not have a moderating effect. We discuss these results regarding the role of different physiological signals and task demands during joint action.

Impact Statement

Despite the inherent multilevel structure of groups, little is known regarding how physiological coupling between group members relates to their behaviors during joint group tasks at multiple levels (individual, dyadic, and group). We showed that the relationship between physiological synchrony and smiling/laughing behaviors made by group members were particularly strong at the group level but nonsignificant at the individual and dyadic levels. By using innovative quantification methods—Multidimensional Recurrence Quantification Analysis—we highlight the importance of modeling data in a way that allows for multilevel considerations within groups.

Interpersonal autonomic nervous system synchrony and its association to relationship and performance - a systematic review and meta-analysis

Interpersonal physiological synchrony is the spontaneous temporal coordination of physiological processes between several individuals. This type of synchrony is critical for human relationships, as it promotes two important outcomes: the quality of the relationships between synchronized individuals, and how well synchronized individuals perform together. Nonetheless a clear estimation of the size of the correlations between interpersonal physiological synchrony and relationship or performance outcomes is missing. To address this gap in knowledge was the main goal of the current meta-analysis. We focused on interpersonal physiological synchrony in measures of autonomic nervous system activity, and specifically we examined the distinct branches of the autonomic nervous system. We conducted two meta-analyses: (1) Estimating the association between interpersonal physiological synchrony and relationship outcomes (2) Estimating the association between interpersonal physiological synchrony and performance outcomes. In the first meta-analysis (i.e., relationships), the overall estimated correlation was small with a marginal significance (ES=0.09, p>.10) and high heterogeneity (I²=76.0%). In further sub-group analysis, we discovered a positive relationship for measures of sympathetic synchrony (ES=0.19, p=.02), a negative relationship for measures of parasympathetic synchrony(ES=-0.21, p=.03), and a positive relationship for measures of combined sympathetic and parasympathetic synchrony (ES =0.16, p=.02). As for the second meta-analysis (i.e., performance), the overall effect size of correlation was small (ES=0.26, p<.01) and heterogeneous (I²=52.7%). Our results emphasize the small effect sizes of the correlations between physiological synchrony and performance or relational outcomes, as well as the differential effects for synchrony in sympathetic versus parasympathetic activity. Combined with the high heterogeneity, our results point to the need for a rigorous a-priori scientific approach which distinguishes between different types of physiological synchrony.

Collaborative Learning Quality Classification Through Physiological Synchrony Recorded by Wearable Biosensors

Interpersonal physiological synchrony has been consistently found during collaborative tasks. However, few studies have applied synchrony to predict collaborative learning quality in real classroom. To explore the relationship between interpersonal physiological synchrony and collaborative learning activities, this study collected electrodermal activity (EDA) and heart rate (HR) during naturalistic class sessions and compared the physiological synchrony between independent task and group discussion task. The students were recruited from a renowned university in China. Since each student learn differently and not everyone prefers collaborative learning, participants were sorted into collaboration and independent dyads based on their collaborative behaviors before data analysis. The result showed that, during group discussions, high collaboration pairs produced significantly higher synchrony than low collaboration dyads (p = 0.010). Given the equivalent engagement level during independent and collaborative tasks, the difference of physiological synchrony between high and low collaboration dyads was triggered by collaboration quality. Building upon this result, the classification analysis was conducted, indicating that EDA synchrony can identify different levels of collaboration quality (AUC = 0.767 and p = 0.015).

When two hearts beat as one: Heart-rate synchrony in social anxiety disorder

Individuals with social anxiety disorder (SAD) experience significant interpersonal impairment. However, little is known about the physiological processes that are associated with interpersonal dysfunction in the disorder. In the present study we examined heart-rate (HR) synchrony in SAD during "getting-acquainted" interactions between opposite-sex partners. Participants included 118 individuals who formed 59 dyads: 30 dyads that included one individual with SAD and one non-socially anxious (NSA) individual (SAD dyads) and 29 dyads that included two NSA individuals (control dyads). Dyads were randomly assigned to either a closeness-generating conversation or a small talk conversation. For closeness-generating conversations, we found that social anxiety was positively associated with HR synchrony in control dyads but negatively associated with HR synchrony in SAD dyads. These results remained when controlling for depressive symptoms and participants' movement. Our findings suggest that in more intimate social contexts, SAD may impair the ability to create HR synchrony between interlocuters and this can have negative relational consequences. Our findings are further discussed in the context of cognitive behavioral and interpersonal models of SAD, and clinical and research implications are delineated.

Gratitude Affects Inter-Subjective Synchronicity for Cognitive Performance and Autonomic Responsiveness

Recently, social neurosciences have been interested in the investigation of neurophysiological responses related to the experience of positive emotions, such as gratitude, during social interactions. Specifically, the aim of the present research was to investigate whether gratitude related to gift exchange could favor cooperative behavior and bond construction, by improving behavioral and autonomic responsivity. At this regard, the autonomic synchronization and behavioral performance of 16 friends coupled in dyads were recorded during a joint attentional task. Gift exchange could be occurred either at the beginning or in the middle of the task. For the recording of simultaneous autonomic activity [heart rate (HR) and skin conductance level (SCL)], a hyperscanning biofeedback paradigm was used. Intra-subjective analysis showed an increase in behavioral [accuracy (ACC)] and autonomic responses (HR and SCL) when the gift exchange took place at the beginning of the task rather than in the middle. Moreover, inter-subjective analysis revealed an increase in behavioral performance and greater autonomic synchronization of HR index. The present research, therefore, shows how gratitude and trust experienced following gift exchange can modify participants’ reactions by creating a shared cognition and the adoption of joint strategies.

Team Physiological Dynamics: A Critical Review

OBJECTIVE

Review the use of physiological measurement in team settings and propose recommendations to improve the state of the science.

BACKGROUND

New sensor and analytical capabilities enable exploration of relationships between team members' physiological dynamics. We conducted a review of physiological measures used in research on teams to understand (1) how these measures are theoretically and operationally related to team constructs and (2) what types of validity evidence exist for physiological measurement in team settings.

METHOD

We identified 32 articles that investigated task-performing teams using physiological data. Articles were coded on several dimensions, including team characteristics. Study findings were categorized by relationships tested between team physiological dynamics (TPD) and team inputs, mediators/processes, outputs, or psychometric properties.

RESULTS

TPD researchers overwhelmingly measure single physiological systems. Although there is research linking TPD to inputs and outputs, the research on processes is underdeveloped.

CONCLUSION

We recommend several theoretical, methodological, and statistical themes to expand the growth of the TPD field.

APPLICATION

Physiological measures, once established as reliable indicators of team functioning, might be used to diagnose suboptimal team states and cue interventions to ameliorate these states.

Surveying 80 Years of Psychodrama Research: A Scientometric Review

Almost a century after Jacob Levy Moreno pioneered the group practice of psychodrama, research in this area has flourished to include different sub-fields of study and psychodramatic intervention for various psychological conditions. By making use of scientometric analysis, particularly document citation analysis and keyword analysis, this study maps out dominant research domains in psychodrama since its inception. From these findings, projections of future research trends and an evaluation of psychodrama research are discussed. Generally, there has been an increased adoption of technology to facilitate psychodrama practice, along with an increasing integration of psychodramatic principles with other psychotherapies. To improve research in this area, this paper recommends greater transparency in the reporting of materials, processes and data used in publications. Finally, we encourage embracing new technological methods such as neuroimaging to provide greater insight into mechanisms of change in psychodrama. The field of psychodrama remains full of potential and innovations to be developed.

When our hearts beat together: Cardiac synchrony as an entry point to understand dyadic co-regulation in couples

The degree to which romantic partners' autonomic responses are coordinated, represented by their pattern of physiological synchrony, seems to capture important aspects of the reciprocal influence and co-regulation between spouses. In this study, we analyzed couple's cardiac synchrony as measured by heart rate (HR) and heart rate variability (HRV). A sample of 27 couples (N = 54) performed a structured interaction task in the lab where they discussed positive and negative aspects of the relationship. During the interaction, their cardiac measures (HR and HRV) were recorded using the BIOPAC System. Additional assessment, prior to the lab interaction task, included self-report measures of empathy (Interpersonal Reactivity Index and Interpersonal Reactivity Index for Couples) and relationship satisfaction (Revised Dyadic Adjustment Scale). Synchrony computation was based on the windowed cross-correlation of both partner's HR and HRV time series. In order to control for random synchrony, surrogate controls were created using segment-wise shuffling. Our results confirmed the presence of cardiac synchrony during the couple's interaction when compared to surrogate testing. Specifically, we found evidence for negative (antiphase) synchrony of couple's HRV and positive (in-phase) synchrony of HR. Further, both HRV and HR synchronies were associated with several dimensions of self-report data. This study suggests that cardiac synchrony, particularly, the direction of the covariation in the partners' physiological time series, may have an important relational meaning in the context of marital interactions.

Infant-adult synchrony in spontaneous and nonspontaneous interactions

Infant-adult synchrony has been reported through observational and experimental studies. Nevertheless, synchrony is addressed differently in both cases. While observational studies measure synchrony in spontaneous infant-adult interactions, experimental studies manipulate it, inducing nonspontaneous synchronous and asynchronous interactions. A still unsolved question is to what extent differ spontaneous synchrony from the nonspontaneous one, experimentally elicited. To address this question, we conducted a study to compare synchrony in both interactional contexts. Forty-three 14-month-old infants were randomly assigned to one of two independent groups: (1) the spontaneous interaction context, consisting of a storytime session; and (2) the nonspontaneous interaction context, where an assistant bounced the infant in synchrony with a stranger. We employed an optical motion capture system to accurately track the time and form of synchrony in both contexts. Our findings indicate that synchrony arising in spontaneous exchanges has different traits than synchrony produced in a nonspontaneous interplay. The evidence presented here offers new insights for rethinking the study of infant-adult synchrony and its consequences on child development.

Physiological synchrony is associated with cooperative success in real-life interactions

Cooperation is pivotal for society to flourish. To foster cooperation, humans express and read intentions via explicit signals and subtle reflections of arousal visible in the face. Evidence is accumulating that humans synchronize these nonverbal expressions and the physiological mechanisms underlying them, potentially influencing cooperation. The current study is designed to verify this putative linkage between synchrony and cooperation. To that end, 152 participants played the Prisoner's Dilemma game in a dyadic interaction setting, sometimes facing each other and sometimes not. Results showed that synchrony in both heart rate and skin conductance level emerged during face-to-face contact. However, only synchrony in skin conductance levels predicted cooperative success of dyads. Crucially, this positive linkage was strengthened when participants could see each other. These findings show the strong relationship between our bodily responses and social behavior, and emphasize the importance of studying social processes between rather than within individuals in real-life interactions.

Subjective Evaluation of Performance in a Collaborative Task Is Better Predicted From Autonomic Response Than From True Achievements

Whereas the fundamental role of the body in social cognition seems to be generally accepted, elucidating the bodily mechanisms associated with non-verbal communication and cooperation between two or more persons is still a challenging endeavor. In this article we propose a fresh approach for investigating the function of the autonomic nervous system that is reflected in parameters of heart rate variability, respiration, and electrodermal activity in a social setting. We analyzed autonomic parameters of dyads solving a target-tracking task together with the partner or individually. A machine classifier was trained to predict the subjects' rating of performance and collaboration either from tracking error data or from the set of autonomic parameters. When subjects collaborated, this classifier could predict the subjective performance ratings better from the autonomic response than from the objective performance of the subjects. However, when they solved the task individually, predictability from autonomic parameters dropped to the level of objective performance, indicating that subjects were more rational in rating their performance in this condition. Moreover, the model captured general knowledge about the population that allows it to predict the performance ratings of an unseen subject significantly better than chance. Our results suggest that, in particular in situations that require collaboration with others, evaluation of performance is shaped by the bodily processes that are quantified by autonomic parameters. Therefore, subjective performance assessments appear to be modulated not only by the output of a rational or discriminative system that tracks the objective performance but to a significant extent also by interoceptive processes.

Prosocial effects of coordination - What, how and why?

A wealth of research in recent decades has investigated the effects of various forms of coordination upon prosocial attitudes and behavior. To structure and constrain this research, we provide a framework within which to distinguish and interrelate different hypotheses about the psychological mechanisms underpinning various prosocial effects of various forms of coordination. To this end, we introduce a set of definitions and distinctions that can be used to tease apart various forms of prosociality and coordination. We then identify a range of psychological mechanisms that may underpin the effects of coordination upon prosociality. We show that different hypotheses about the underlying psychological mechanisms motivate different predictions about the effects of various forms of coordination in different circumstances.

Is It Easy to Synchronize Our Minds When We Are Forced to Cooperate?

There is increasing scientific interest in elucidating the biological mechanisms underlying cooperative behaviors. Humans have developed a high degree of complexity in their cooperativity, which has been defined as hyper-cooperativity. An interesting biological marker to study how two individuals are emotionally linked when they cooperate is their psychophysiological synchronization (the overlapping of signals as indicators of Autonomous Nervous System activation). Hence, the main aim of this study was to explore participants’ psychophysiological synchronization, based on electrocardiograms (ECG) and galvanic skin response (GSR) signals in a sample of strangers who were set up to cooperate (n = 29 pairs of same sex strangers; mean age = 20.52 ± 1.72), compared to participants who were forced to compete (n = 22 pairs of same sex strangers; mean age = 20.45 ± 1.53) in a laboratory setting. Moreover, the roles of the participants’ gender and the outcomes (positive or negative) obtained in the cooperation were examined as potential moderators of this psychophysiological synchronization. Results showed a progressive increase in ECG and GSR signal synchronization in participants who cooperated, reaching the highest levels of synchronization during the recovery period. Moreover, cooperation induced higher GSR synchronization in comparison with competition. Finally, although gender played an important role in the psychophysiological synchronization during cooperation (women presented the highest overlapping of GSR signals), feedback about the participants’ performance was not significantly associated with their psychophysiological synchronization. Therefore, research in this field would help us to understand more about the body’s physiological responses to different types of social interactions, such as cooperation and competition, providing an opportunity to establish interaction strategies that would be physiologically desirable.

Cooperation Between Strangers in Face-to-Face Dyads Produces More Cardiovascular Activation Than Competition or Working Alone

Abstract. Individual and shared goals can be achieved through social interpersonal interaction, cooperation and competition being two different yet similar strategies to reach such aims and objectives. Nevertheless, there is a gap in the literature analyzing the effect of these types of social interactions, especially in cooperation, on autonomic nervous system responses using noninvasive measures, such as heart rate (HR). The regulation of HR and other cardiovascular variables of the central nervous system offers information about how to encourage or discourage social engagement and prosocial behaviors. In fact, a more flexible engagement with the environment and efficient emotions regulation is enabled by an efficient cardiac control. Hence, the main aim of this study was to investigate heart rate variability (HRV) in strangers (180 healthy young participants) who were set to cooperate or compete in face-to-face dyads (between same-gender participants) or to work alone (as the control condition), considering outcomes in these tasks (positive or negative) and gender as moderating variables. We found that participants who cooperated had higher HRs and lower high frequency (HF) HRV than those who competed and/or worked alone. Regarding gender and outcome, men who cooperate and lose have lower HF-HRV levels than men on the simple task with negative outcomes. Hence, our study indicates that cooperation between strangers in face-to-face dyads may produce less parasympathetic activation than competition or working on the task without any social interaction. Research in this field may help us understand the psychophysiological basis of social interaction, providing an opportunity to establish interaction strategies that would be physiologically desirable, in order to promote well-being.

Social frame and tax compliance modulate electrophysiological and autonomic responses following tax-related decisions

Given the intrinsic complexity of cognitive and affective processes affecting how people reason about taxes and their decisions to be compliant with such social duty, we aimed at exploring those latent processes by combining the analysis of their central and peripheral physiological correlates. We asked participants to make realistic economic decisions concerning tax-payment and manipulated the social vs. individual decisional frame. In addition, we took into account the potential role of tax-compliance trait. Thirty self-employed professionals took part in the study and completed a public good game while their autonomic (skin conductance – SC – and heart rate – HR) and neural brain (electroencephalography – EEG) activities were recorded. The analysis of physiological responses during the feedback phase – where participants could be presented or not with a fiscal audit – highlighted: (i) increased tonic SC levels and theta activity in the social condition than in the individual one; (ii) increased HR values when a fiscal audit did not take place, especially in participants who presented an enforced tax-compliance trait. Present findings support the idea that classic economic theories of tax behaviour developed under the assumption that taxpayers act as rational and individualist agents do not provide a comprehensive account for the decision-making process. They add to available evidence highlighting the contribution of psychological and social-affective variables to individuals’ decision-making processes to pay or evade taxes and to their appraisal of the consequences of such choice, as suggested by the ‘slippery slope’ framework.

Impact of humor-related communication elements in natural dyadic interactions on interpersonal physiological synchrony

Evidence suggests that in dyadic conversations some alignment occurs at the physiological level, but relatively little is known about the conditions that may facilitate physiological synchrony of two interlocutors. In the present interdisciplinary study, the impact of specific linguistic features of ongoing dialogues-the use of humor-related communication elements-was examined in 24 male dyads who were meeting for the first time. Heart rate synchrony was quantified using phase synchronization, which reflects the degree of moment-to-moment adjustments that occur between the two persons of a dyad. Comical hypotheticals and verbal amplifiers were identified and quantified using cognitive-linguistic methods of corpus analysis. Additionally, smiles following these communication elements were identified using the Facial Action Coding System. The data showed that the heart rate time series of the two interlocutors were to some extent synchronized in phase, and that the magnitude of this synchronization exceeded what had to be expected by chance. The strength of heart rate synchrony in a dyad was the higher the more comical hypotheticals were produced, independently from how much the two conversation partners were in sum talking to each other. A similar observation was made for verbal amplifiers, but their effect depended on whether they were perceived (and acknowledged by a smile) as humorous. The findings are in line with the more general notion that physiological synchrony may be enhanced by shared experience and suggest that the use of (reciprocated) humor may speed up the building of rapport among communication partners.

Inhibition of left anterior intraparietal sulcus shows that mutual adjustment marks dyadic joint-actions in humans

Creating real-life dynamic contexts to study interactive behaviors is a fundamental challenge for the social neuroscience of interpersonal relations. Real synchronic interpersonal motor interactions involve online, inter-individual mutual adaptation (the ability to adapt one’s movements to those of another in order to achieve a shared goal). In order to study the contribution of the left anterior Intra Parietal Sulcus (aIPS) (i.e. a region supporting motor functions) to mutual adaptation, here, we combined a behavioral grasping task where pairs of participants synchronized their actions when performing mutually adaptive imitative and complementary movements, with the inhibition of activity of aIPS via non-invasive brain stimulation. This approach allowed us to investigate whether aIPS supports online complementary and imitative interactions. Behavioral results showed that inhibition of aIPS selectively impairs pair performance during complementary compared to imitative interactions. Notably, this effect depended on pairs’ mutual adaptation skills and was higher for pairs composed of participants who were less capable of adapting to each other. Thus, we provide the first causative evidence for a role of the left aIPS in supporting mutually adaptive interactions and show that the inhibition of the neural resources of one individual of a pair is compensated at the dyadic level.

Visuo-motor interference with a virtual partner is equally present in cooperative and competitive interactions

Automatic imitation of observed actions is thought to be a powerful mechanism, one that may mediate the reward value of interpersonal interactions, but that could also generate visuo-motor interference when interactions involve complementary movements. Since interpersonal coordination seems to be crucial both when cooperating and competing with others, the questions arises as to whether imitation-and thus visuo-motor interference-occurs in both scenarios. To address this issue, we asked human participants to engage in high- or low-interactive (Interactive or Cued condition, respectively), cooperative or competitive, joint reach-to-grasps with a virtual partner. More specifically, interactions occurred in: (i) a Cued condition, where participants simply adapted their movement timing to synchronize with (during cooperation) or anticipate (during competition) the virtual partner's grasp; (ii) an Interactive condition requiring the same adaptation, as well as a real-time selection of their action according to the virtual character's movement. To simulate a realistic human-human interaction, the virtual character would change its movement speed in consecutive trials according to participants' behaviour. Results demonstrate that visuo-motor interference-as indexed by movement kinematics (higher maximum wrist height during complementary compared to imitative power grips)-emerge in both cooperative and competitive motor interactions only when predictions about the partner's movements are needed to perform one's own action (interactive condition). These results support the idea that simulative imitation is heavily present when individuals need to match their behaviours closely.

Interpersonal Coordination: Methods, Achievements, and Challenges

Research regarding interpersonal coordination can be traced back to the early 1960s when video recording began to be utilized in communication studies. Since then, technological advances have extended the range of techniques that can be used to accurately study interactional phenomena. Although such a diversity of methods contributes to the improvement of knowledge concerning interpersonal coordination, it has become increasingly difficult to maintain a comprehensive view of the field. In the present article, we review the main capture methods by describing their major findings, levels of description and limitations. We group them into three categories: video analysis, motion tracking, and psychophysiological and neurophysiological techniques. Revised evidence suggests that interpersonal coordination encompasses a family of morphological and temporal synchronies at different levels and that it is closely related to the construction and maintenance of a common social and affective space. We conclude by arguing that future research should address methodological challenges to advance the understanding of coordination phenomena.

"Are We in Sync with Each Other?" Exploring the Effects of Cosleeping on Heterosexual Couples' Sleep Using Simultaneous Polysomnography: A Pilot Study

The present study aimed to explore dynamic and interactive aspects of cosleep in heterosexual couples. The sample consisted of eight young healthy adults who belonged to four heterosexual couples with a good relationship quality and a history of cosleeping. All individuals underwent simultaneous polysomnography in a sleep laboratory for four nights in which they slept individually and with their partner. Also, a sleep protocol of subjective sleep measures was completed. Statistical analyses included cross recurrence quantification analysis to assess synchronization during sleep. Cosleeping was associated with better subjective sleep quality, increased total sleep time, sleep efficiency, total slow wave sleep, and REM sleep. Sleep stages were more synchronized during cosleep independent of awakenings. Cardiorespiratory measures remained unchanged. The results indicate that young healthy couples in good relationships benefit from cosleeping on a subjective and objective level. Combining simultaneous polysomnography and cross recurrence quantification analysis is a promising method to study dynamic and interactive aspects of cosleep possibly leading to deeper understanding of the role of sleep for sociality, the nature of REM sleep, and the partner as a social zeitgeber. Moreover, clinical implications may arise from these findings.

Beyond Synchrony: Joint Action in a Complex Production Task Reveals Beneficial Effects of Decreased Interpersonal Synchrony

A variety of joint action studies show that people tend to fall into synchronous behavior with others participating in the same task, and that such synchronization is beneficial, leading to greater rapport, satisfaction, and performance. It has been noted that many of these task environments require simple interactions that involve little planning of action coordination toward a shared goal. The present study utilized a complex joint construction task in which dyads were instructed to build model cars while their hand movements and heart rates were measured. Participants built these models under varying conditions, delimiting how freely they could divide labor during a build session. While hand movement synchrony was sensitive to the different tasks and outcomes, the heart rate measure did not show any effects of interpersonal synchrony. Results for hand movements show that the more participants were constrained by a particular building strategy, the greater their behavioral synchrony. Within the different conditions, the degree of synchrony was predictive of subjective satisfaction and objective product outcomes. However, in contrast to many previous findings, synchrony was negatively associated with superior products, and, depending on the constraints on the interaction, positively or negatively correlated with higher subjective satisfaction. These results show that the task context critically shapes the role of synchronization during joint action, and that in more complex tasks, not synchronization of behavior, but rather complementary types of behavior may be associated with superior task outcomes.

Multidimensional Recurrence Quantification Analysis (MdRQA) for the Analysis of Multidimensional Time-Series: A Software Implementation in MATLAB and Its Application to Group-Level Data in Joint Action

We introduce Multidimensional Recurrence Quantification Analysis (MdRQA) as a tool to analyze multidimensional time-series data. We show how MdRQA can be used to capture the dynamics of high-dimensional signals, and how MdRQA can be used to assess coupling between two or more variables. In particular, we describe applications of the method in research on joint and collective action, as it provides a coherent analysis framework to systematically investigate dynamics at different group levels-from individual dynamics, to dyadic dynamics, up to global group-level of arbitrary size. The Appendix in Supplementary Material contains a software implementation in MATLAB to calculate MdRQA measures.

Coordination and Collective Performance: Cooperative Goals Boost Interpersonal Synchrony and Task Outcomes

Whether it be a rugby team or a rescue crew, ensuring peak group performance is a primary goal during collective activities. In reality, however, groups often suffer from productivity losses that can lead to less than optimal outputs. Where researchers have focused on this problem, inefficiencies in the way team members coordinate their efforts has been identified as one potent source of productivity decrements. Here, we set out to explore whether performance on a simple object movement task is shaped by the spontaneous emergence of interpersonally coordinated behavior. Forty-six pairs of participants were instructed to either compete or cooperate in order to empty a container of approximately 100 small plastic balls as quickly and accurately as possible. Each trial was recorded to video and a frame-differencing approach was employed to estimate between-person coordination. The results revealed that cooperative pairs coordinated to a greater extent than their competitive counterparts. Furthermore, coordination, as well as movement regularity were positively related to accuracy, an effect that was most prominent when the task was structured such that opportunities to coordinate were restricted. These findings are discussed with regard to contemporary theories of coordination and collective performance.

Observing joint action: Coordination creates commitment

Previous research has shown that interpersonal coordination enhances pro-social attitudes and behavior. Here, we extend this research by investigating whether the degree of coordination observed in a joint action enhances the perception of individuals' commitment to the joint action. In four experiments, participants viewed videos of joint actions. In the low coordination condition, two agents made independent individual contributions to a joint action. In the high coordination condition, the individual contributions were tightly linked. Participants judged whether and for how long the observed agents would resist a tempting outside option and remain engaged in the joint action. The results showed that participants were more likely to expect agents to resist outside options when observing joint actions with a high degree of coordination. This indicates that observing interpersonal coordination is sufficient to enhance the perception of commitment to joint action.

On Cooperative Behavior in Distributed Teams: The Influence of Organizational Design, Media Richness, Social Interaction, and Interaction Adaptation

Self-interest vs. cooperation is a fundamental dilemma in animal behavior as well as in human and organizational behavior. In organizations, how to get people to cooperate despite or in conjunction with their self-interest is fundamental to the achievement of a common goal. While both organizational designs and social interactions have been found to further cooperation in organizations, some of the literature has received contradictory support, just as very little research, if any, has examined their joint effects in distributed organizations, where communication is usually achieved via different communication media. This paper reviews the extant literature and offers a set of hypotheses to integrate current theories and explanations. Further, it discusses how future research should examine the joint effects of media, incentives, and social interactions.

Interpersonal Autonomic Physiology: A Systematic Review of the Literature

Interpersonal autonomic physiology is defined as the relationship between people’s physiological dynamics, as indexed by continuous measures of the autonomic nervous system. Findings from this field of study indicate that physiological activity between two or more people can become associated or interdependent, often referred to as physiological synchrony. Physiological synchrony has been found in both new and established relationships across a range of contexts, and it correlates with a number of psychosocial constructs. Given these findings, interpersonal physiological interactions are theorized to be ubiquitous social processes that co-occur with observable behavior. However, this scientific literature is fragmented, making it difficult to evaluate consistency across reports. In an effort to facilitate more standardized scholarly approaches, this systematic review provides a description of existing work in the area and highlights theoretical, methodological, and statistical issues to be addressed in future interpersonal autonomic physiology research.