Collective music listening: Movement energy is enhanced by groove and visual social cues

Cognitive benefits of music in aerobic exercise: Evidence from a Bayesian network meta-analysis in adults with mild cognitive impairment

Aerobic exercise improves cognitive functions in older adults with mild cognitive impairment (MCI), while dance, combining music and synchronized movement, offers additional cognitive benefits. Despite music's potential role in enhancing cognitive outcomes, most research on aerobic exercise has not considered the impact of accompanying music. This review compared the effectiveness of aerobic exercise with music, aerobic exercise without music, and dance on cognitive function in adults with MCI. A total of 38 papers from 25 randomized controlled trials (N = 2048) were synthesized. The multilevel meta-analyses showed that compared to the control group, global cognition was improved by aerobic exercise with music (g = 1.2 [0.47, 1.94]), aerobic exercise without music (g = 0.48 [0.18, 0.79]), and dance (g = 0.55 [0.13, 0.96]). Dance also enhanced short-term memory (g = 0.41 [0.24, 0.59]), learning efficiency (g = 0.39 [0.14, 0.65]), and retrieval fluency (g = 0.7 [0.19, 1.22]). Bayesian network meta-analyses indicated that aerobic exercise with music had the highest probability of being the most effective for improving global cognition, executive function, and processing speed. Dance was likely to be the most beneficial for enhancing short-term memory, learning efficiency, and retrieval fluency. This study supports that incorporating music in exercise amplifies the cognitive benefits beyond exercise alone for individuals with MCI. The "Music Exercise Synergy Model" is proposed to explain the cognitive benefits of combining music with exercise. Dance strategically uses music for coordination, offering psychological, social, cognitive, and neurobiological benefits and contributing to the observed enhancements in memory functions.

Social motor synchrony and interactive rapport in autistic, non-autistic, and mixed-neurotype dyads

LAY ABSTRACT

During social interactions, people often mirror each other's movements and gestures, a process called synchrony. This synchrony helps foster a sense of connection, understanding, and ease in communication. While research suggests that autistic people may show less synchrony in their movements compared to non-autistic people, the implications of this difference for building rapport remain unclear. Specifically, it is unknown whether synchrony plays a similar role in rapport-building for autistic individuals as it does for non-autistic individuals, particularly in interactions with autistic versus non-autistic partners. This study had three goals to investigate whether synchrony is lower in conversations involving at least one autistic person; to explore the relationship between synchrony and rapport; and to compare how much autistic and non-autistic people rely on synchrony to feel connected. The findings suggest that while synchrony positively influences rapport more strongly in non-autistic interactions, autistic individuals may rely less on synchrony for rapport. These results highlight differences in how social connection is built, offering deeper insight into social interactions for autistic and non-autistic people.

Cortical oscillations are modified by expertise in dance and music: Evidence from live dance audience

Over the past decades, the focus of brain research has expanded from using strictly controlled stimuli towards understanding brain functioning in complex naturalistic contexts. Interest has increased in measuring brain processes in natural interaction, including classrooms, theatres, concerts and museums to understand the brain functions in the real world. Here, we examined how watching a live dance performance with music in a real-world dance performance setting engages the brains of the spectators. Expertise in dance or music has been shown to modify brain functions, including when watching dance or listening to music. Therefore, we recorded electroencephalography (EEG) from an audience of dancers, musicians and novices as they watched the live dance performance and analysed their cortical oscillations. We compared intrabrain oscillations when participants watched the performance (with music) or listened to the music alone without the dance. We found that dancers have stronger fronto-central and parieto-occipital theta phase synchrony (4-8 Hz) than novices when watching dance, likely reflecting the effects of dance experience on motor imagery, multisensory and social interaction processes. Also, compared with novices, dancers had stronger delta phase synchrony (0.5-4 Hz) when listening to music, and musicians had stronger delta phase synchrony when watching dance, suggesting expertise in music and dance enhances sensitivity or attention to temporal regularities in movement and sound.

The geometry of interpersonal synchrony in human dance

Collective synchronized behavior has powerful social-communicative functions observed across several animal taxa.1,2,3,4,5,6,7 Operationally, synchronized behavior can be explained by individuals responding to shared external cues (e.g., light, sound, or food) as well as by inter-individual adaptation.3,8,9,10,11 We contrasted these accounts in the context of a universal human practice-collective dance-by recording full-body kinematics from dyads of laypersons freely dancing to music in a "silent disco" setting. We orthogonally manipulated musical input (whether participants were dancing to the same, synchronous music) and visual contact (whether participants could see their dancing partner). Using a data-driven method, we decomposed full-body kinematics of 70 participants into 15 principal movement patterns, reminiscent of common dance moves, explaining over 95% of kinematic variance. We find that both music and partners drive synchrony, but through distinct dance moves. This leads to distinct kinds of synchrony that occur in parallel by virtue of a geometric organization: anteroposterior movements such as head bobs synchronize through music, while hand gestures and full-body lateral movements synchronize through visual contact. One specific dance move-vertical bounce-emerged as a supramodal pacesetter of coordination, synchronizing through both music and visual contact, and at the pace of the musical beat. These findings reveal that synchrony in human dance is independently supported by shared musical input and inter-individual adaptation. The independence between these drivers of synchrony hinges on a geometric organization, enabling dancers to synchronize to music and partners simultaneously by allocating distinct synchronies to distinct spatial axes and body parts.

Improvisation and live accompaniment increase motor response and reward during a music playing task

Music provides a reward that can enhance learning and motivation in humans. While music is often combined with exercise to improve performance and upregulate mood, the relationship between music-induced reward and motor output is poorly understood. Here, we study music reward and motor output at the same time by capitalizing on music playing. Specifically, we investigate the effects of music improvisation and live accompaniment on motor, autonomic, and affective responses. Thirty adults performed a drumming task while (i) improvising or maintaining the beat and (ii) with live or recorded accompaniment. Motor response was characterized by acceleration of hand movements (accelerometry), wrist flexor and extensor muscle activation (electromyography), and the drum strike count (i.e., the number of drum strikes played). Autonomic arousal was measured by tonic response of electrodermal activity (EDA) and heart rate (HR). Affective responses were measured by a 12-item Likert scale. The combination of improvisation and live accompaniment, as compared to all other conditions, significantly increased acceleration of hand movements and muscle activation, as well as participant reports of reward during music playing. Improvisation, regardless of type of accompaniment, increased the drum strike count and autonomic arousal (including tonic EDA responses and several measures of HR), as well as participant reports of challenge. Importantly, increased motor response was associated with increased reward ratings during music improvisation, but not while participants were maintaining the beat. The increased motor responses achieved with improvisation and live accompaniment have important implications for enhancing dose of movement during exercise and physical rehabilitation.

Research Trends in Virtual Reality Music Concert Technology: A Systematic Literature Review

Advances in virtual reality (VR) technology have sparked novel avenues of growth in the musical domain. Following the COVID-19 pandemic, the rise of VR technology has led to growing interest in VR music concerts as an alternative to traditional live concerts. These virtual settings can provide immersion like attending real concerts for physically distant audiences and performers, and also can offer new creative possibilities. VR music concert research is still in its infancy, and advances in technologies such as multimodal devices are rapidly expanding the diversity of research, requiring a unified understanding of the field. To identify trends in VR music concert technology, we conducted a PRISMA-based systematic literature review covering the period from 2018 to 2023. After a thorough screening process, a total of 27 papers were selected for review. The studies were classified and analyzed based on the research topic (audience, performer, concert venue), interaction type (user-environment, user-user), and hardware used (head-mounted display, additional hardware). Furthermore, we categorized the evaluation metrics into user experience, usability, and performance. Our review contributes to advancing the understanding of recent developments in VR music concert technology, shedding light on the diversification and potential of this emerging field.

Testing an acoustic model of the P-center in English and Japanese

The notion of the "perceptual center" or the "P-center" has been put forward to account for the repeated finding that acoustic and perceived syllable onsets do not necessarily coincide, at least in the perception of simple monosyllables or disyllables. The magnitude of the discrepancy between acoustics and perception-the location of the P-center in the speech signal- has proven difficult to estimate, though acoustic models of the effect do exist. The present study asks if the P-center effect can be documented in natural connected speech of English and Japanese and examines if an acoustic model that defines the P-center as the moment of the fastest energy change in a syllabic amplitude envelope adequately reflects the P-center in the two languages. A sensorimotor synchronization paradigm was deployed to address the research questions. The results provide evidence for the existence of the P-center effect in speech of both languages while the acoustic P-center model is found to be less applicable to Japanese. Sensorimotor synchronization patterns further suggest that the P-center may reflect perceptual anticipation of a vowel onset.

A review of psychological and neuroscientific research on musical groove

When listening to music, we naturally move our bodies rhythmically to the beat, which can be pleasurable and difficult to resist. This pleasurable sensation of wanting to move the body to music has been called "groove." Following pioneering humanities research, psychological and neuroscientific studies have provided insights on associated musical features, behavioral responses, phenomenological aspects, and brain structural and functional correlates of the groove experience. Groove research has advanced the field of music science and more generally informed our understanding of bidirectional links between perception and action, and the role of the motor system in prediction. Activity in motor and reward-related brain networks during music listening is associated with the groove experience, and this neural activity is linked to temporal prediction and learning. This article reviews research on groove as a psychological phenomenon with neurophysiological correlates that link musical rhythm perception, sensorimotor prediction, and reward processing. Promising future research directions range from elucidating specific neural mechanisms to exploring clinical applications and socio-cultural implications of groove.

Interperformer coordination in piano-singing duo performances: phrase structure and empathy impact

Musicians' body motion plays a fundamental role in ensemble playing, by supporting sound production, communication, and expressivity. This research investigates how Western classical musicians' head motion during ensemble performances relates to a piece's phrase structure and musicians' empathic perspective taking (EPT) profile. Twenty-four advanced piano and singing students took part in the study, and their EPT score was pre-assessed using the Interpersonal Reactivity Index. High and low EPT duos were formed, and musicians were paired with a co-performer from the same and the other EPT group. Musicians rehearsed Fauré's Automne and Schumann's Die Kartenlegerin, and performed the pieces one time before and three times after rehearsal. Motion capture data of the musicians' front head, audio, and MIDI recordings of the performances were collected and analysed. Similarity in musicians' head motion and tendency to lead/lag their co-performer were computed by extracting, respectively, power and phase difference of the cross-wavelet transforms of the velocity curves of each paired marker. Results demonstrate that the power of interperformer coordination corresponds to the piece's phrase levels and that singer's EPT can impact the leader-follower relationships between musicians, depending on piece and take number. In the Fauré piece, the higher the singer's EPT score, the higher the tendency for the singer to lead and pianist to follow in take 3, and the lower the tendency for the singer to lead and pianist to follow in take 2. These results contribute to a further understanding of the mechanisms underpinning social interactions, by revealing the complexity of the association between empathy and body motion in ensembles in promoting and diffusing leadership between musicians.

Social and nonlinear dynamics unite: musical group synchrony

Synchronization, the human tendency to align behaviors in time with others, is necessary for many survival skills. The ability to synchronize actions with rhythmic (predictable) sound patterns is especially well developed in music making. Recent models of synchrony in musical ensembles rely on pairwise comparisons between group members. This pairwise approach to synchrony has hampered theory development, given current findings from social dynamics indicating shifts in members' influence within larger groups. We draw on social theory and nonlinear dynamics to argue that emergent properties and novel roles arise in musical group synchrony that differ from individual or pairwise behaviors. This transformational shift in defining synchrony sheds light on successful outcomes as well as on disruptions that cause negative behavioral outcomes.

Audience synchronies in live concerts illustrate the embodiment of music experience

A study of 132 audience members of three classical public concerts (all three staged the same chamber music pieces by Ludwig van Beethoven, Brett Dean, and Johannes Brahms) had the goal of analyzing the physiological and motor responses of audiences. It was assumed that the music would induce synchronous physiology and movement in listeners (induction synchrony). In addition to hypothesizing that such synchronies would be present, we expected that they were linked to participants' aesthetic experiences, their affect and personality traits, which were assessed by questionnaires before and after the concerts. Clear evidence was found of physiological synchrony (heart rate, respiration rate, skin conductance response) as well as movement synchrony of the audiences, whereas breathing behavior was not synchronized. Thus the audiences of the three concerts resonated with the music, their music perception was embodied. There were links between the bodily synchrony and aesthetic experiences: synchrony, especially heart-rate synchrony, was higher when listeners felt moved emotionally and inspired by a piece, and were immersed in the music. Personality traits were also associated with the individual contributions to induction synchrony.

From distal to proximal to interactive: behavioral and brain synchrony during attraction, courtship, and sexual interaction-implications for clinical assessments of relationship style and quality

INTRODUCTION

Synchronous behaviors between individuals are nonverbal signs of closeness and common purpose. In the flow from initial attraction to intimate sexual interaction, attention and synchrony move from distal to proximal to interactive and are mediated by sensitized activation of neural systems for sexual motivation, arousal, and desire and those that recognize and mimic common facial and body movements between individuals. When reinforced by sexual pleasure and other relationship rewards, this results in the strengthening of attraction and bonding and the display of more common motor patterns. As relationships falter, nonverbal behaviors likely become asynchronous.

OBJECTIVES

To define behavioral, romantic, and sexual synchrony during phases of attraction and how their disruption can be observed and utilized by clinicians to assess individual relationship styles and quality.

METHODS

We review the literature on behavioral and attentional synchrony in humans and animals in an effort to understand experiential and innate mechanisms of synchrony and asynchrony and how they develop, as well as implications for attraction, relationship initiation, maintenance of romantic and sexual closeness, and relationship disintegration.

RESULTS

Evidence is presented that behavioral synchrony and the neural mechanisms that underlie it are vital to relationship formation and satisfaction.

CONCLUSION

Behavioral synchrony helps to create feelings of sexual and romantic synergy, cohesion, and arousal among individuals. Asynchrony is aversive and can spark feelings of discontent, aversion, and jealousy. Thus, observing patterns of nonverbal sexual and romantic synchrony between individuals offers insights into the potential quality of their relationships.

A concert for babies: Attentional, affective, and motor responses in an infant audience

Many of our most powerful musical experiences are shared with others, and researchers have increasingly investigated responses to music in group contexts. Though musical performances for infants are growing in popularity, most research on infants' responses to live music has focused on solitary caregiver-infant pairs. Here, we report infants' attentional, affective, and motor responses to live music as audience members. Two groups of caregiver-infant (6-18 months) pairs (50 total) watched a short musical performance with two song styles - lullaby and playsong. Caregivers were instructed to watch passively or interactively. The playsong captured more infant attention and, especially in the interactive condition, elicited more infant smiles. Notably, infant attention was more coordinated with their own caregiver than a random caregiver, and infants with no experience attending group musical events in the past were especially attentive to the performance. Infants were more likely to generate movements when parents remained still. Overall, infants' responses to live musical performance in an audience were influenced by song style, caregiver behavior, and their own musical histories. A video abstract of this article can be viewed at https://www.youtube.com/watch?v=q61qnDMW8dU. RESEARCH HIGHLIGHTS: Infants' responses to live musical performances are shaped by the music, by their caregivers, and by their own musical histories During a concert for babies, a playsong more effectively elicited infant attention and smiles than a lullaby, especially when caregivers were interactive Infant attention was more coordinated with their own caregiver than with other caregivers watching the same show.

Does interpersonal liking lead to interpersonal synchrony in musical contexts?

The causal relationship of interpersonal liking affecting interpersonal synchrony is inconsistently documented. This study tests whether (a) interpersonal liking increases both behavioural and perceived synchrony and (b) people will synchronise with an agreeable partner over a competing musical stimulus. We had college students (N = 25) shake an egg-shaker with an agreeable or disagreeable confederate without music, with music, and with specific instruction to synchronise. Participants reported liking the agreeable confederate more than the disagreeable confederate and rated their relationship more positively; however, both behavioural and perceived synchrony were unaffected by the agreeableness of the confederate. Thus, we failed to replicate previous findings in an auditory only context. Furthermore, participants who believed they were more synchronised with the confederate liked the confederate more and felt more like a team, but the degree of behavioural synchrony was unrelated to these social perceptions. Perception of synchrony appears to be more important for social bonding than behavioural synchrony.

Interpersonal synchronization of spontaneously generated body movements

Interpersonal movement synchrony (IMS) is central to social behavior in several species. In humans, IMS is typically studied using structured tasks requiring participants to produce specific body movements. Instead, spontaneously generated (i.e., not instructed) movements have received less attention. To test whether spontaneous movements synchronize interpersonally, we recorded full-body kinematics from dyads of participants who were only asked to sit face-to-face and to look at each other. We manipulated interpersonal (i) visual contact and (ii) spatial proximity. We found that spontaneous movements synchronized across participants only when they could see each other and regardless of interpersonal spatial proximity. This synchronization emerged very rapidly and did not selectively entail homologous body parts (as in mimicry); rather, the synchrony generalized to nearly all possible combinations of body parts. Hence, spontaneous behavior alone can lead to IMS. More generally, our results highlight that IMS can be studied under natural and unconstrained conditions.

Creating a shared musical interpretation: Changes in coordination dynamics while learning unfamiliar music together

The ability to coordinate with others is fundamental for humans to achieve shared goals. Often, harmonious interpersonal coordination requires learning, such as ensemble musicians rehearing together to synchronize their low-level timing and high-level aesthetic musical expressions. We investigated how the coordination dynamics of a professional string quartet changed as they learned unfamiliar pieces together across eight trials. During all trials, we recorded each musician's body sway motion data, and quantified the group's body sway similarity (cross-correlation) and information flow (Granger causality) on each trial. In line with our hypothesis, group similarity increased, while group information flow decreased significantly across trials. In addition, there was a trend such that group similarity, but not information flow, was related to the quality of the performances. As the ensemble converged on a joint interpretation through rehearsing, their body sways reflected the change from interpersonal information flow for coordinative mutual adaptations and corrections, to synchronous musical coordination made possible by the musicians learning a common internally based expressive interpretation.

Music we move to: Spotify audio features and reasons for listening

Previous literature has shown that music preferences (and thus preferred musical features) differ depending on the listening context and reasons for listening (RL). Yet, to our knowledge no research has investigated how features of music that people dance or move to relate to particular RL. Consequently, in two online surveys, participants (N = 173) were asked to name songs they move to (“dance music”). Additionally, participants (N = 105) from Survey 1 provided RL for their selected songs. To investigate relationships between the two, we first extracted audio features from dance music using the Spotify API and compared those features with a baseline dataset that is considered to represent music in general. Analyses revealed that, compared to the baseline, the dance music dataset had significantly higher levels of energy, danceability, valence, and loudness, and lower speechiness, instrumentalness and acousticness. Second, to identify potential subgroups of dance music, a cluster analysis was performed on its Spotify audio features. Results of this cluster analysis suggested five subgroups of dance music with varying combinations of Spotify audio features: “fast-lyrical”, “sad-instrumental”, “soft-acoustic”, “sad-energy”, and “happy-energy”. Third, a factor analysis revealed three main RL categories: “achieving self-awareness”, “regulation of arousal and mood”, and “expression of social relatedness”. Finally, we identified variations in people’s RL ratings for each subgroup of dance music. This suggests that certain characteristics of dance music are more suitable for listeners’ particular RL, which shape their music preferences. Importantly, the highest-rated RL items for dance music belonged to the “regulation of mood and arousal” category. This might be interpreted as the main function of dance music. We hope that future research will elaborate on connections between musical qualities of dance music and particular music listening functions.

The Groove Enhancement Machine (GEM): A Multi-Person Adaptive Metronome to Manipulate Sensorimotor Synchronization and Subjective Enjoyment

Synchronization of movement enhances cooperation and trust between people. However, the degree to which individuals can synchronize with each other depends on their ability to perceive the timing of others’ actions and produce movements accordingly. Here, we introduce an assistive device—a multi-person adaptive metronome—to facilitate synchronization abilities. The adaptive metronome is implemented on Arduino Uno circuit boards, allowing for negligible temporal latency between tapper input and adaptive sonic output. Across five experiments—two single-tapper, and three group (four tapper) experiments, we analyzed the effects of metronome adaptivity (percent correction based on the immediately preceding tap-metronome asynchrony) and auditory feedback on tapping performance and subjective ratings. In all experiments, tapper synchronization with the metronome was significantly enhanced with 25–50% adaptivity, compared to no adaptation. In group experiments with auditory feedback, synchrony remained enhanced even at 70–100% adaptivity; without feedback, synchrony at these high adaptivity levels returned to near baseline. Subjective ratings of being in the groove, in synchrony with the metronome, in synchrony with others, liking the task, and difficulty all reduced to one latent factor, which we termed enjoyment. This same factor structure replicated across all experiments. In predicting enjoyment, we found an interaction between auditory feedback and metronome adaptivity, with increased enjoyment at optimal levels of adaptivity only with auditory feedback and a severe decrease in enjoyment at higher levels of adaptivity, especially without feedback. Exploratory analyses relating person-level variables to tapping performance showed that musical sophistication and trait sadness contributed to the degree to which an individual differed in tapping stability from the group. Nonetheless, individuals and groups benefitted from adaptivity, regardless of their musical sophistication. Further, individuals who tapped less variably than the group (which only occurred ∼25% of the time) were more likely to feel “in the groove.” Overall, this work replicates previous single person adaptive metronome studies and extends them to group contexts, thereby contributing to our understanding of the temporal, auditory, psychological, and personal factors underlying interpersonal synchrony and subjective enjoyment during sensorimotor interaction. Further, it provides an open-source tool for studying such factors in a controlled way.

Crossmodal Correspondence between Music and Ambient Color Is Mediated by Emotion

The quality of a concert hall primarily depends on its acoustics. But does visual input also have an impact on musical enjoyment? Does the color of ambient lighting modulate the perceived music quality? And are certain colors perceived to fit better than others with a given music piece? To address these questions, we performed three within-subjects experiments. We carried out two pretests to select four music pieces differing in tonality and genre, and 14 lighting conditions of varying hue, brightness, and saturation. In the main experiment, we applied a fully crossed repeated-measures design. Under each of the four lighting conditions, participants rated the musical variables ‘Harmonic’, ‘Powerful’, ‘Gloomy’, ‘Lively’ and overall liking of the music pieces, as well as the perceived fit of music and lighting. Subsequently, participants evaluated music and lighting separately by rating the same variables as before, as well as their emotional impact (valence, arousal, dominance). We found that music and lighting being similarly rated in terms of valence and arousal in the unimodal conditions were judged to match better when presented together. Accordingly, tonal (atonal) music was rated to fit better with weakly saturated (highly saturated) colors. Moreover, some characteristics of the lighting were carried over to music. That is, just as red lighting was rated as more powerful than green and blue lighting, music was evaluated to be more powerful under red compared to green and blue lighting. We conclude that listening to music is a multisensory process enriched by impressions from the visual domain.

Analyzing multidimensional movement interaction with generalized cross-wavelet transform

Humans are able to synchronize with musical events whilst coordinating their movements with others. Interpersonal entrainment phenomena, such as dance, involve multiple body parts and movement directions. Along with being multidimensional, dance movement interaction is plurifrequential, since it can occur at different frequencies simultaneously. Moreover, it is prone to nonstationarity, due to, for instance, displacements around the dance floor. Various methodological approaches have been adopted for the study of human entrainment, but only spectrogram-based techniques allow for an integral analysis thereof. This article proposes an alternative approach based upon the cross-wavelet transform, a state-of-the-art technique for nonstationary and plurifrequential analysis of univariate interaction. The presented approach generalizes the cross-wavelet transform to multidimensional signals. It allows to identify, for different frequencies of movement, estimates of interaction and leader-follower dynamics across body parts and movement directions. Further, the generalized cross-wavelet transform can be used to quantify the frequency-wise contribution of individual body parts and movement directions to overall movement synchrony. Since both in- and anti-phase relationships are dominant modes of coordination, the proposed implementation ignores whether movements are identical or opposite in phase. The article provides a thorough mathematical description of the method and includes proofs of its invariance under translation, rotation, and reflection. Finally, its properties and performance are illustrated via four examples using simulated data and behavioral data collected through a mirror game task and a free dance movement task.

Interbrain emotional connection during music performances is driven by physical proximity and individual traits

How musical emotions and the pleasure derived from music, regardless of the musical valence, can be shared between individuals is a fascinating question, and investigating it can shed light on the function of musical reward. We carried out our investigations in a natural setting during an international competition for orchestra conductors. Participants (n = 15) used a dedicated smartphone app to report their subjective emotional experiences in real time while we recorded their cerebral activity using electroencephalography and their electrodermal activity. The overall behavioral real-time behavioral ratings suggest a possible social influence on the reported and felt pleasure. The physically closer the participants, the more similar their reported pleasure. By calculating the interindividual cerebral coherence (n = 21 pairs), we showed that when people simultaneously reported either high or low pleasure, their cerebral activities were closer than for simultaneous neutral pleasure reports. Participants' skin conductance levels were also more coupled when reporting higher emotional degrees simultaneously. More importantly, the participants who were physically closer had higher cerebral coherence, but only when they simultaneously reported a high level of pleasure. We propose that emotional contagion and/or emotional resonance mechanisms could explain why a form of "emotional connecting force" arises between people during shared appraisal situations.

Bridging the gap between emotion and joint action

Our daily human life is filled with a myriad of joint action moments, be it children playing, adults working together (i.e., team sports), or strangers navigating through a crowd. Joint action brings individuals (and embodiment of their emotions) together, in space and in time. Yet little is known about how individual emotions propagate through embodied presence in a group, and how joint action changes individual emotion. In fact, the multi-agent component is largely missing from neuroscience-based approaches to emotion, and reversely joint action research has not found a way yet to include emotion as one of the key parameters to model socio-motor interaction. In this review, we first identify the gap and then stockpile evidence showing strong entanglement between emotion and acting together from various branches of sciences. We propose an integrative approach to bridge the gap, highlight five research avenues to do so in behavioral neuroscience and digital sciences, and address some of the key challenges in the area faced by modern societies.

Unifying Large- and Small-Scale Theories of Coordination

Coordination is a ubiquitous feature of all living things. It occurs by virtue of informational coupling among component parts and processes and can be quite specific (as when cells in the brain resonate to signals in the environment) or nonspecific (as when simple diffusion creates a source–sink dynamic for gene networks). Existing theoretical models of coordination—from bacteria to brains to social groups—typically focus on systems with very large numbers of elements (N→∞) or systems with only a few elements coupled together (typically N = 2). Though sharing a common inspiration in Nature’s propensity to generate dynamic patterns, both approaches have proceeded largely independent of each other. Ideally, one would like a theory that applies to phenomena observed on all scales. Recent experimental research by Mengsen Zhang and colleagues on intermediate-sized ensembles (in between the few and the many) proves to be the key to uniting large- and small-scale theories of coordination. Disorder–order transitions, multistability, order–order phase transitions, and especially metastability are shown to figure prominently on multiple levels of description, suggestive of a basic Coordination Dynamics that operates on all scales. This unified coordination dynamics turns out to be a marriage of two well-known models of large- and small-scale coordination: the former based on statistical mechanics (Kuramoto) and the latter based on the concepts of Synergetics and nonlinear dynamics (extended Haken–Kelso–Bunz or HKB). We show that models of the many and the few, previously quite unconnected, are thereby unified in a single formulation. The research has led to novel topological methods to handle the higher-dimensional dynamics of coordination in complex systems and has implications not only for understanding coordination but also for the design of (biorhythm inspired) computers.