Autism and social disconnection in interpersonal rocking

Evidence of mutual non-verbal synchrony in learners with severe learning disability and autism, and their support workers: a motion energy analysis study

Introduction

Some research indicates that neurodivergent people are less likely than "neurotypical" people to adapt their movements to a partner's movements to facilitate interpersonal motor synchrony. Researchers therefore suggest synchrony deficits underlie the social differences associated with autism and other neurodivergences. Intensive Interaction (II) is a client-led approach, where Learning Support Workers (LSW) follow the lead of learners to create balanced and reciprocal interactions.

Methods

We aimed to examine the balance of synchrony in learners with autism and Severe Learning Disabilities and their LSWs in a special education college where learners had prior experience with II. Using Motion Energy Analysis, we assessed the degree to which each partner acted as a leader, and hence which partner acted as a follower, during moments of close synchrony.

Results

Overall, learners and LSWs showed higher than chance synchrony. There were no differences in the degree to which each partner led the moments of synchrony, or the amount pairs synchronized with zero-lag, where there was no delay between each partners' movements.

Discussion

The equal balance of leading and following in the learner and LSW pairs demonstrates that both partners consistently adapted their movements to their partner's movements to facilitate synchrony. The findings tentatively challenge the notion of a synchrony deficit in autism and suggest synchrony can be present in cross-neurotype pairs in comfortable and engaging conditions. We discuss the potential for client-led, movement-based approaches to support smooth interactions across neurotypes.

Social motor synchrony in autism spectrum conditions: A systematic review

LAY ABSTRACT

When two people interact, they often fall into sync with one another by moving their bodies at the same time. Some say autistic people are not as good as non-autistic people at moving at the same time as a partner. This has led some researchers to ask whether measuring synchrony might help diagnose autism. We reviewed the research so far to look at differences in Social Motor Synchrony (SMS) (the way we move together) between autistic people and people they interact with. The research suggests that interactions involving an autistic partner (either two autistic partners, or an autistic and non-autistic partner) show lower synchrony than a non-autistic pair. However, we recognised elements in the research so far that may have affected SMS in interactions involving an autistic person. One way SMS may have been affected in research so far might be the way interactions have been set up in the research studies. Few papers studied interactions between two autistic people or looked at synchrony in comfortable environments with autistic-preferred tasks. The studies also do not explain why synchrony might be different, or weaker, in pairs involving autistic partners. We use these limitations to suggest improvements for future research.

Spontaneous tempo production in cockatiels (Nymphicus hollandicus) and jungle crows (Corvus macrorhynchos)

Musical and rhythmical abilities are poorly documented in non-human animals. Most of the existing studies focused on synchronisation performances to external rhythms. In humans, studies demonstrated that rhythmical processing (e. g. rhythm discrimination or synchronisation to external rhythm) is dependent of an individual measure: the individual tempo. It is assessed by asking participants to produce an endogenous isochronous rhythm (known as spontaneous motor tempo) without any specific instructions nor temporal cue. In non-human animal literature, studies describing spontaneous and endogenous production of motor tempo without any temporal clue are rare. This exploratory study aims to describe and compare the spontaneous motor tempo of cockatiels and jungle crows. Data were collected on spontaneous beak drumming behaviours of birds housed in laboratory. Inter beak strokes intervals were calculated from sound tracks of videos. The analyses revealed that inter beak strokes intervals are non-randomly distributed intervals and are isochronous. Recorded spontaneous motor tempos are significantly different among some cockatiels. Since we could only conduct statistical analysis with one corvid, we cannot conclude about this species. Our results suggest that cockatiels and jungle crows have individual tempos, thus encouraging further investigations.

Social-Motor Coordination Between Peers: Joint Action Developmental Trajectories in ASD and TD

Coordinating a physical movement in time and space with social and nonsocial partners to achieve a shared goal - "joint action" (JA) - characterizes many peer-engagement situations that pose challenges for individuals with autism spectrum disorder (ASD). This cross-sectional study examined development of JA capabilities comparing ASD versus typically developing (TD) groups in early childhood, preadolescence, and adolescence while performing mirroring and complementing JA tasks with social (peer) and nonsocial (computer) partners. Results indicated better motor coordination abilities on computerized tasks than in peer dyads, with larger peer-dyad deficits shown by the ASD group. Developmental growth in JA abilities emerged, but the ASD group lagged behind same-age peers with TD. Socio-motor interventions may offer new channels to facilitate peer engagement in ASD.

Interpersonal motor synchrony in autism: a systematic review and meta-analysis

Introduction

Interpersonal motor synchrony (IMS) is the spontaneous, voluntary, or instructed coordination of movements between interacting partners. Throughout the life cycle, it shapes social exchanges and interplays with intra- and inter-individual characteristics that may diverge in Autism Spectrum Disorder (ASD). Here we perform a systematic review and meta-analysis to summarize the extant literature and quantify the evidence about reduced IMS in dyads including at least one participant with a diagnosis of ASD.

Methods

Empirical evidence from sixteen experimental studies was systematically reviewed, encompassing spontaneous and instructed paradigms as well as a paucity of measures used to assess IMS. Of these, thirteen studies (n = 512 dyads) contributed measures of IMS with an in situ neurotypical partner (TD) for ASD and control groups, which could be used for meta-analyses.

Results

Reduced synchronization in ASD-TD dyads emerged from both the systematic review and meta-analyses, although both small and large effect sizes (i.e., Hedge's g) in favor of the control group are consistent with the data (Hedge's g = .85, p < 0.001, 95% CI[.35, 1.35], 95% PI[-.89, 2.60]).

Discussion

Uncertainty is discussed relative to the type of task, measures, and age range considered in each study. We further discuss that sharing similar experiences of the world might help to synchronize with one another. Future studies should not only assess whether reduced IMS is consistently observed in ASD-TD dyads and how this shapes social exchanges, but also explore whether and how ASD-ASD dyads synchronize during interpersonal exchanges.

Dynamic mutual predictions during social learning: A computational and interbrain model

During social interactions, we constantly learn about the thoughts, feelings, and personality traits of our interaction partners. Learning in social interactions is critical for bond formation and acquiring knowledge. Importantly, this type of learning is typically bi-directional, as both partners learn about each other simultaneously. Here we review the literature on social learning and propose a new computational and neural model characterizing mutual predictions that take place within and between interactions. According to our model, each partner in the interaction attempts to minimize the prediction error of the self and the interaction partner. In most cases, these inferential models become similar over time, thus enabling mutual understanding to develop. At the neural level, this type of social learning may be supported by interbrain plasticity, defined as a change in interbrain coupling over time in neural networks associated with social learning, among them the mentalizing network, the observation-execution system, and the hippocampus. The mutual prediction model constitutes a promising means of providing empirically verifiable accounts of how relationships develop over time.

Social interaction links active musical rhythm engagement and expressive communication in autistic toddlers

Rhythm is implicated in both social and linguistic development. Rhythm perception and production skills are also key vulnerabilities in neurodevelopmental disorders such as autism which impact social communication. However, direct links between musical rhythm engagement and expressive communication in autism is not clearly evident. This absence of a direct connection between rhythm and expressive communication indicates that the mechanism of action between rhythm and expressive communication may recruit other cognitive or developmental factors. We hypothesized that social interactions, including general interpersonal relationships and interactive music-making involving children and caregivers, were a significant such factor, particularly in autism. To test this, we collected data from parents of autistic and nonautistic children 14-36 months of age, including parent reports of their children's rhythmic musical engagement, general social skills, parent-child musical interactions, and expressive communication skills. Path analysis revealed a system of independent, indirect pathways from rhythmic musical engagement to expressive communication via social skills and parent-child musical interactions in autistic toddlers. Such a system implies both that social and musical interactions represent crucial links between rhythm and language and that different kinds of social interactions play parallel, independent roles linking rhythmic musical engagement with expressive communication skills.

The Dynamical Hypothesis in Situ: Challenges and Opportunities for a Dynamical Social Approach to Interpersonal Coordination

Over the past three decades, Van Gelder's dynamical hypothesis has been instrumental in reconceptualizing the ways in which perception-action-cognition unfolds over time and in context. Here, I examine how the dynamical approach has enriched the theoretical understanding of social dynamics within cognitive science, with a particular focus on interpersonal coordination. I frame this review around seven principles in dynamical systems: three that are well-represented in interpersonal coordination research to date (emergent behavior, context-sensitive behavior, and attractors) and four that could be useful opportunities for future growth (hysteresis, sensitivity to initial conditions, equifinality, and reciprocal compensation). In addition to identifying specific promising lines of theoretical inquiry, I focus on the significant potential afforded by computationally intensive science-especially in naturally occurring data or trace data. Building on the foundation laid over the past three decades, I argue that looking to increasingly situated and naturalistic settings (and data) is not only necessary to realize the full commitment to the dynamical hypothesis but is also critical to building parsimonious and principled theories of social phenomena.

Joint intention understanding in children with autism spectrum disorder

This study examined the ability of children with autism spectrum disorder (ASD) to generate joint intention-based action prediction in a joint action task. Children were presented with a series of videos in which two actors either played with blocks based on joint intention (social condition) or played with blocks independently (nonsocial condition). In the familiarization stage, two actors demonstrated how they played with blocks three times. In the test stage, one actor left the scene, and another actor grasped a block and asked where she should place it. Children's gaze behavior was assessed by an eye tracker. After watching videos, children were asked to answer two questions: an action prediction question and an intention understanding question. The results showed that in the implicit eye movement task, children with ASD and typically developing (TD) children exhibited location-based anticipatory gaze under both conditions. However, in terms of explicit behavioral responses, TD children showed higher accuracy in response to action prediction questions and intention understanding questions than children with ASD in the social condition, while no significant group difference was found in the nonsocial condition. These results indicate that children with ASD have difficulty understanding joint intention and that their action prediction is primarily driven by bottom-up sensory inputs.

Beyond simultaneity: Temporal interdependence of behavior is key to affiliative effects of interpersonal synchrony in children

Interpersonal synchrony (IPS) is the temporal coordination of behavior during social interactions. IPS acts as a social cue signifying affiliation both when children witness IPS between others and when they experience it themselves. However, it is unclear which temporal qualities of IPS produce these effects and why. We hypothesized that both the simultaneity and temporal regularity of partners' actions would influence affiliation judgments and that subjective perceptions of IPS ("togetherness") would play a role in mediating these relations. In two online tasks, children aged 4 to 11 years listened to a pair of children tapping (witnessed IPS; n = 68) or themselves tapped with another child (experienced IPS; n = 63). Tapping partners were presented as real, but the sounds attributed to them were computer generated so that their temporal relations could be experimentally manipulated. The simultaneity and regularity of their tapping was systematically manipulated across trials. For witnessed IPS, both the simultaneity and regularity of partners' tapping significantly positively affected the perceived degree of affiliation between them. These effects were mediated by the perceived togetherness of the tapping. No affiliative effects of IPS were found in the experienced IPS condition. Our findings suggest that both the simultaneity and regularity of partners' actions influence children's affiliation judgments when witnessing IPS via elicited perceptions of togetherness. We conclude that temporal interdependence-which includes but is not limited to simultaneity of action-is responsible for inducing perceptions of affiliation during witnessed IPS.

Children with autism spectrum disorder perform comparably to their peers in a parent-child cooperation task

This study investigates whether and how parent's cooperation affects child's cooperation, and whether that differs between children with/without autism spectrum disorder (ASD). The experiment involved a cooperative key-pressing task completed first by parent-parent dyads and then by parent-child dyads, meanwhile brain activity in the right frontal-parietal cortex of dyad partners was measured synchronously. The results showed the following: ASD children exhibited performance comparable to those of their peers, as was the level of brain synchronization with their parents, which was mainly due to parents with ASD children tending to adjust their own response patterns to match those of their children. These findings suggest that parents can somewhat actively mitigate the lower interpersonal synchronization ability of ASD children, in behavioral or/and neural level.

Synchrony to a beat predicts synchrony with other minds

Synchrony has been used to describe simple beat entrainment as well as correlated mental processes between people, leading some to question whether the term conflates distinct phenomena. Here we ask whether simple synchrony (beat entrainment) predicts more complex attentional synchrony, consistent with a common mechanism. While eye-tracked, participants listened to regularly spaced tones and indicated changes in volume. Across multiple sessions, we found a reliable individual difference: some people entrained their attention more than others, as reflected in beat-matched pupil dilations that predicted performance. In a second study, eye-tracked participants completed the beat task and then listened to a storyteller, who had been previously recorded while eye-tracked. An individual's tendency to entrain to a beat predicted how strongly their pupils synchronized with those of the storyteller, a corollary of shared attention. The tendency to synchronize is a stable individual difference that predicts attentional synchrony across contexts and complexity.

Digitally assisted diagnostics of autism spectrum disorder

Digital technologies have the potential to support psychiatric diagnostics and, in particular, differential diagnostics of autism spectrum disorder in the near future, making clinical decisions more objective, reliable and evidence-based while reducing clinical resources. Multimodal automatized measurement of symptoms at cognitive, behavioral, and neuronal levels combined with artificial intelligence applications offer promising strides toward personalized prognostics and treatment strategies. In addition, these new technologies could enable systematic and continuous assessment of longitudinal symptom development, beyond the usual scope of clinical practice. Early recognition of exacerbation and simplified, as well as detailed, progression control would become possible. Ultimately, digitally assisted diagnostics will advance early recognition. Nonetheless, digital technologies cannot and should not substitute clinical decision making that takes the comprehensive complexity of individual longitudinal and cross-section presentation of autism spectrum disorder into account. Yet, they might aid the clinician by objectifying decision processes and provide a welcome relief to resources in the clinical setting.

Effects of Parental Involvement in Robot-Assisted Autism Therapy

Parental involvement in traditional autism therapy is key to the effective treatment of children with ASD. Little is known about parental involvement in robot-assisted autism therapy (RAAT)-novel therapeutic support for children with ASD. Our study investigates the effect of parental presence on multiple-session RAAT conducted with 16 children with ASD. They interacted with the social robot in the presence or absence of their parents. We measured children's socio-behavioral outcomes and conducted semi-structured interviews with parents. Parents did not necessarily affect the children's outcomes during the interventions. However, children's autism-related symptoms resulted in different socio-behavioral outcomes between sessions with and without parents. Most parents have reported positive changes in their children's behaviors when interacting with the robot.

[The mechanisms involved in rocking toddlers]

If the tactile modality is fundamental in the infant's experience, there is a particular situation in which it is mobilized: rocking. Carrying a baby in one's arms or trying to soothe him will spontaneously lead the adult to rock him, whatever his culture. The ways of carrying out this rhythmic movement are varied, but all are characterized by a synchronous combination of somesthesic and vestibular stimulations repeated at regular intervals. The specificities of the tactile, vestibular and temporal modalities involved in rocking highlight the way in which rocking provides an essential support to the sensory and social development of the infant.

Parent-Child Nonverbal Engagement During Read Versus Sung Book-Sharing in Preschoolers with and without ASD

Providing natural opportunities that scaffold interpersonal engagement is important for supporting social interactions for young children with Autism spectrum disorder (ASD). Musical activities are often motivating, familiar, and predictable, and may support both children and their interaction partners by providing opportunities for shared social engagement. We assessed multiple facets of nonverbal social engagement - child and caregiver visual attention and interpersonal movement coordination - during musical (song) and non-musical (picture) book-sharing contexts in caregiver-child dyads of preschoolers with (n = 13) and without (n = 16) ASD. Overall, children with ASD demonstrated reduced visual attention during the book sharing activity, as well as reduced movement coordination with their caregivers, compared to children with typical development. Children in both diagnostic groups, as well as caregivers, demonstrated greater visual attention (gaze toward the activity and/or social partner) during song books compared to picture books. Visual attention behavior was correlated between children and caregivers in the ASD group but only in the song book condition. Findings highlight the importance of considering how musical contexts impact the behavior of both partners in the interaction. Musical activities may support social engagement by modulating the behavior of both children and caregivers.

Lactobacillus plantarum ST-III modulates abnormal behavior and gut microbiota in a mouse model of autism spectrum disorder

Probiotic treatment might improve autism spectrum disorder (ASD) behavior. In this study, we investigated the improvement effects of Lactobacillus plantarum ST-III on a mouse model of ASD, which was constructed using triclosan. After two weeks of L. plantarum ST-III oral feeding, autism-like social deficits in male mouse models were ameliorated. L. plantarum ST-III also attenuated the self-grooming and freezing times of female mice. High-throughput sequencing revealed changes in the gut microbiota after L. plantarum ST-III intervention. In the female probiotic group, the abundance of beneficial Lachnospiraceae bacteria increased, whereas that of harmful Alistipes bacteria decreased. Correlation analysis showed that amelioration of abnormal behavior in a mouse model of ASD was related to the involvement of certain metabolic pathways. A reduction in the abundance of Alistipes was involved in stereotyped behavioral improvement. Thus, oral supplementation with L. plantarum ST-III can help improve social behavior in a male mouse model of ASD and contribute to more balanced intestinal homeostasis.

Inter-brain plasticity as a biological mechanism of change in psychotherapy: A review and integrative model

Recent models of psychopathology and psychotherapy highlight the importance of interpersonal factors. The current review offers a biological perspective on these interpersonal processes by examining inter-brain synchrony—the coupling of brain activity between people interacting with one another. High inter-brain synchrony is associated with better relationships in therapy and in daily life, while deficits in the ability to achieve inter-brain synchrony are associated with a variety of psychological and developmental disorders. The review suggests that therapy improves patients’ ability to achieve such synchrony through inter-brain plasticity—a process by which recurring exposure to high inter-brain synchrony leads to lasting change in a person’s overall ability to synchronize. Therapeutic sessions provide repeated situations with high inter-brain synchrony. This can lead to a long-term increase in the ability to synchronize, first with the therapist, then generalized to other interpersonal relationships, ultimately leading to symptom reduction. The proposed inter-brain plasticity model offers a novel biological framework for understanding relational change in psychotherapy and its links to various forms of psychopathology and provides testable hypotheses for future research. Understanding this mechanism may help improve existing psychotherapy methods and develop new ones.

Synchrony During Online Encounters Affects Social Affiliation and Theory of Mind but Not Empathy

Moving together in time affects human social affiliation and cognition. However, it is unclear whether these effects hold for on-line video meetings and whether they extend to empathy (understanding or sharing others' emotions) and theory of mind (ToM; attribution of mental states to others). 126 young adult participants met through online video in unacquainted pairs. Participants either performed 3 min of synchronous arm movements paced by sounds (n = 40), asynchronous movements (n = 46) or a small talk condition (n = 40). In a subsequent empathy task, participants engaged in a conversation. A video recording of this conversation was played back, and each participant rated, at predetermined time points, how they felt and how they thought their partner felt. From this we calculated empathic accuracy (accuracy of the estimation of the other's emotions) and emotional congruence (emotion sharing). ToM was measured by showing videos of geometrical shapes interacting and asking the participants to describe what happened, measuring the amount of intentionality. We found that participants in the synchrony condition rated feeling greater closeness and similarity to their partners relative to the asynchronous condition. Further, participants in the synchrony group tended to ascribe more intentionality to the abstract shapes than participants in asynchrony condition, suggesting greater ToM. Synchrony and asynchrony groups did not reliably differ in empathic accuracy nor emotional congruence. These results suggest that moving in synchrony has effects on social affiliation measures even in online encounters. These effects extend to ToM tendencies but not empathic accuracy or emotion sharing. These results highlight the potential of synchronous movement in online encounters to affect a subset of social cognition and affiliation measures.

The Components of Interpersonal Synchrony in the Typical Population and in Autism: A Conceptual Analysis

Interpersonal synchrony – the tendency for social partners to temporally co-ordinate their behaviour when interacting – is a ubiquitous feature of social interactions. Synchronous interactions play a key role in development, and promote social bonding and a range of pro-social behavioural outcomes across the lifespan. The process of achieving and maintaining interpersonal synchrony is highly complex, with inputs required from across perceptual, temporal, motor, and socio-cognitive domains. In this conceptual analysis, we synthesise evidence from across these domains to establish the key components underpinning successful non-verbal interpersonal synchrony, how such processes interact, and factors that may moderate their operation. We also consider emerging evidence that interpersonal synchrony is reduced in autistic populations. We use our account of the components contributing to interpersonal synchrony in the typical population to identify potential points of divergence in interpersonal synchrony in autism. The relationship between interpersonal synchrony and broader aspects of social communication in autism are also considered, together with implications for future research.

A Case for Playful Engagement: Synchrony and Interaction Quality During Mirroring in ASD. Conceptual Framework and Case Study

The social challenges in autism spectrum disorders (ASD) can present as qualitative differences in interactions that make individuals on the autism spectrum appear less engaged with others. Limited interactional synchrony and other nonverbal movement patterns may contribute to these qualitative differences. This article uses the case of Hans, an adult on the autism spectrum, to describe patterns of synchrony and interaction quality during mirroring activities in dance/movement therapy. Raters scored videos of Hans and his partners on affective engagement, flow of the interaction, and interpersonal synchrony. They also qualitatively described his movements and interactions. Hans consistently participated in mirroring, but showed different patterns of attention and engagement when leading, following, interacting, or dancing in an open-ended dance. Hans was able to move in synchrony with partners, showed positive affect, and increased his movement repertoire by returning to others’ movements in later sessions. He was the most engaged when following a playful movement theme with a dance/movement therapy student partner. His affective engagement increased, but only in the less structured open-ended dance and only across the five sessions with this same dance/movement therapy student partner, and not when the sessions with his other partners, including others on the autism spectrum, were included. This points to a potential need to have dance/movement therapists model developing a movement relationship using flexible and playful contexts to emotionally engage the individual and reflect the complexity of everyday social situations. We present clinical recommendations and suggestions for future studies.

Early Onset of Impairments of Interpersonal Motor Synchrony in Preschool-Aged Children with Autism Spectrum Disorder

Characteristics of interpersonal motor synchrony in individuals with autism spectrum disorder (ASD) have been investigated only in older children and adolescents, which calls for investigations in younger samples. The interpersonal motor synchrony was compared between preschool-aged children with (n = 23) and without ASD (n = 24) during free plays with familiar teachers. Children with ASD exhibited reduced synchrony of the upper body and trunk compared with typically developing (TD) children. Moreover, the degree of synchrony in ASD group was not above than chance. For autistic children, interpersonal motor synchrony was negatively correlated with aspects of autistic traits. The results suggest that the impairment of interpersonal motor synchrony has an onset earlier than school age and is a potential pathway for understanding autistic traits.

Adaptive Empathy: A Model for Learning Empathic Responses in Response to Feedback

Empathy is usually deployed in social interactions. Nevertheless, common measures and examinations of empathy study this construct in isolation from the person in distress. In this article we seek to extend the field of examination to include both empathizer and target to determine whether and how empathic responses are affected by feedback and learned through interaction. Building on computational approaches in feedback-based adaptations (e.g., no feedback, model-free and model-based learning), we propose a framework for understanding how empathic responses are learned on the basis of feedback. In this framework, adaptive empathy, defined as the ability to adapt one's empathic responses, is a central aspect of empathic skills and can provide a new dimension to the evaluation and investigation of empathy. By extending existing neural models of empathy, we suggest that adaptive empathy may be mediated by interactions between the neural circuits associated with valuation, shared distress, observation-execution, and mentalizing. Finally, we propose that adaptive empathy should be considered a prominent facet of empathic capabilities with the potential to explain empathic behavior in health and psychopathology.

Integration and Causality in Enactive Approaches to Psychiatry

In this paper I address what has been called the integration problem in psychiatry. This problem is tied to conceptions of causality and explanatory levels in our understanding of mind. I take an interdisciplinary enactive perspective to develop a 3-fold method for exploring the dynamics of integration, based on a concept of dynamical causation and a non-hierarchical (level-free) notion of gestalt. I also consider Autism Spectrum Disorder (ASD) as a test case.

Excessive and less complex body movement in children with autism during face-to-face conversation: An objective approach to behavioral quantification

The majority of existing studies investigating characteristics of overt social behavior in individuals with autism spectrum disorder (ASD) relied on informants' evaluation through questionnaires and behavioral coding techniques. As a novelty, this study aimed to quantify the complex movements produced during social interactions in order to test differences in ASD movement dynamics and their convergence, or lack thereof, during social interactions. Twenty children with ASD and twenty-three children with typical development (TD) were videotaped while engaged in a face-to-face conversation with an interviewer. An image differencing technique was utilized to extract the movement time series. Spectral analyses were conducted to quantify the average power of movement, and the fractal scaling of movement. The degree of complexity matching was calculated to capture the level of behavioral coordination between the interviewer and children. Results demonstrated that the average power was significantly higher (p < 0.01), and the fractal scaling was steeper (p < 0.05) in children with ASD, suggesting excessive and less complex movement as compared to the TD peers. Complexity matching occurred between children and interviewers, but there was no reliable difference in the strength of matching between the ASD and TD children. Descriptive trends in the interviewer's behavior suggest that her movements adapted to match both ASD and TD movements equally well. The findings of our study might shed light on seeking novel behavioral markers of ASD, and on developing automatic ASD screening techniques during daily social interactions.

Social context facilitates visuomotor synchrony and bonding in children and adults

Interpersonal synchrony is a fundamental part of human social interaction, with known effects on facilitating social bonding. Moving in time with another person facilitates prosocial behaviour, however, it is unknown if the degree of synchronisation predicts the degree of social bonding. Similarly, while people readily fall in synchrony even without being instructed to do so, we do not know whether such spontaneous synchronisation elicits similar prosocial effects as instructed synchronisation. Across two studies, we investigated how context (social vs non-social stimulus) and instruction (instructed vs uninstructed) influenced synchronisation accuracy and bonding with the interaction partner in adults and children. The results revealed improved visuomotor synchrony within a social, compared to non-social, context in adults and children. Children, but not adults, synchronised more accurately when instructed to synchronise than when uninstructed. For both children and adults, synchronisation in a social context elicited stronger social bonding towards an interaction partner as compared to synchronisation in a non-social context. Finally, children's, but not adults', degree of synchrony with the partner was significantly associated with their feelings of social closeness. These findings illuminate the interaction of sensorimotor coupling and joint action in social contexts and how these mechanisms facilitate synchronisation ability and social bonding.

Effects of Creative Movement Therapies on Social Communication, Behavioral-Affective, Sensorimotor, Cognitive, and Functional Participation Skills of Individuals With Autism Spectrum Disorder: A Systematic Review

Autism Spectrum Disorder (ASD) is a neurodevelopmental disorder affecting multiple developmental domains including social communication, behavioral-affective, sensorimotor, and cognitive systems. There is growing evidence for the use of holistic, whole-body, Creative Movement Therapies (CMT) such as music, dance, yoga, theater, and martial arts in addressing the multisystem impairments in ASD. We conducted a comprehensive quantitative and qualitative review of the evidence to date on the effects of CMT on multiple systems in individuals with ASD. The strongest evidence, both in terms of quantity and quality, exists for music and martial arts-based interventions followed by yoga and theater, with very limited research on dance-based approaches. Our review of 72 studies (N = 1,939 participants) across participants with ASD ranging from 3 to 65 years of age suggests that at present there is consistent evidence from high quality studies for small-to-large sized improvements in social communication skills following music and martial arts therapies and medium-to-large improvements in motor and cognitive skills following yoga and martial arts training, with insufficient evidence to date for gains in affective, sensory, and functional participation domains following CMT. Although promising, our review serves as a call for more rigorous high-quality research to assess the multisystem effects of CMT in ASD. Based on the existing literature, we discuss implications of our findings for autism researchers and also provide evidence-based guidelines for clinicians to incorporate CMT approaches in their plan of care for individuals with ASD.

The Mirroring Dance: Synchrony and Interaction Quality of Five Adolescents and Adults on the Autism Spectrum in Dance/Movement Therapy

Background: Individuals on the autism spectrum are often described as having atypical social interactions. Ideally, interactional synchrony helps any interaction flow smoothly with each individual responding verbally, non-verbally, and/or emotionally within a short timeframe. Differences in interactional synchrony may impact how individuals on the autism spectrum experience social encounters. Method: This mixed methods pilot study examined interactional synchrony in five cases of adolescents and adults on the autism spectrum through secondary analysis of video of the participants in movement-based mirroring tasks during dance/movement therapy. Raters described the movement and interactions of the participants while they were leading and following mirroring and engaged in open-ended free dances with a partner. Videos were also scored on measures of affective engagement, flow of the interaction, and synchrony. Results: One of the most striking findings of this study was the difference between engagement in the instructions of the task and engagement with the partner: participants often followed the instructions for the mirroring tasks with little further social engagement with their partner. When participants did engage in moments of social initiation, attunement to the partner, and interactive behaviors, these did not develop into longer interactions. A paired t-test of the correlation coefficients for each participant showed that scores on synchrony and affective engagement were more strongly positively correlated in the less structured open-ended dance and in video clips of interactive behaviors, than in the videos of simply leading or following mirroring. Synchrony was also significantly more strongly positively correlated with the observed flow of the interaction than with observed affective engagement. With the small sample size, however, most of the correlation coefficients were not significant and should be tested on a larger sample. Discussion: Interpersonal synchrony may not be sufficient to effectively support social engagement when individuals on the autism spectrum simply follow instructions to synchronize their movements. Synchrony-based interventions may therefore need to include more complex open-ended social scenarios as interactional synchrony may then be more correlated with perceived interaction quality. Therapists may also need to partner with participants to model using non-verbal social behaviors to develop interactions within mirroring tasks.

Rhythm and timing as vulnerabilities in neurodevelopmental disorders

Millions of children are impacted by neurodevelopmental disorders (NDDs), which unfold early in life, have varying genetic etiologies and can involve a variety of specific or generalized impairments in social, cognitive and motor functioning requiring potentially lifelong specialized supports. While specific disorders vary in their domain of primary deficit (e.g. autism spectrum disorder (social), attention-deficit/hyperactivity disorder (attention), developmental coordination disorder (motor) and developmental language disorder (language)), comorbidities between NDDs are common. Intriguingly, many NDDs are associated with difficulties in skills related to rhythm, timing and synchrony though specific profiles of rhythm/timing impairments vary across disorders. Impairments in rhythm/timing may instantiate vulnerabilities for a variety of NDDs and may contribute to both the primary symptoms of each disorder as well as the high levels of comorbidities across disorders. Drawing upon genetic, neural, behavioural and interpersonal constructs across disorders, we consider how disrupted rhythm and timing skills early in life may contribute to atypical developmental cascades that involve overlapping symptoms within the context of a disorder's primary deficits. Consideration of the developmental context, as well as common and unique aspects of the phenotypes of different NDDs, will inform experimental designs to test this hypothesis including via potential mechanistic intervention approaches. This article is part of the theme issue 'Synchrony and rhythm interaction: from the brain to behavioural ecology'.

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

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

Shifts in Behavioral Synchrony in Response to an Interaction Partner's Distress in Adolescents With and Without ASD

Individuals with Autism spectrum disorder (ASD) show altered behavioral synchrony and empathic behavior. Yet, an ecologically valid examination of these in adolescents is still required. We employed a social interaction sequence comprising a friendly conversation with a confederate, an expression of distress by her, and a return to friendly conversation. 44 male adolescents (22 with ASD) participated. Socio-emotional behaviors, coded by blind raters and through automated analyses of motion, were analyzed. Results indicated reduced synchrony in the ASD group. Moreover, whereas controls displayed a decrease in synchrony when facing another's distress, adolescents with ASD showed no such change. No group differences were found on empathic behavior. Findings imply gaps between verbal and non-verbal responses of adolescents with ASD to a distressed interaction partner.

Spontaneous emergence of leadership patterns drives synchronization in complex human networks

Synchronization of human networks is fundamental in many aspects of human endeavour. Recently, much research effort has been spent on analyzing how motor coordination emerges in human groups (from rocking chairs to violin players) and how it is affected by coupling structure and strength. Here we uncover the spontaneous emergence of leadership (based on physical signaling during group interaction) as a crucial factor steering the occurrence of synchronization in complex human networks where individuals perform a joint motor task. In two experiments engaging participants in an arm movement synchronization task, in the physical world as well as in the digital world, we found that specific patterns of leadership emerged and increased synchronization performance. Precisely, three patterns were found, involving a subtle interaction between phase of the motion and amount of influence. Such patterns were independent of the presence or absence of physical interaction, and persisted across manipulated spatial configurations. Our results shed light on the mechanisms that drive coordination and leadership in human groups, and are consequential for the design of interactions with artificial agents, avatars or robots, where social roles can be determinant for a successful interaction.

Modality-specific attractor dynamics in dyadic entrainment

Rhythmic joint coordination is ubiquitous in daily-life human activities. In order to coordinate their actions towards shared goals, individuals need to co-regulate their timing and move together at the collective level of behavior. Remarkably, basic forms of coordinated behavior tend to emerge spontaneously as long as two individuals are exposed to each other's rhythmic movements. The present study investigated the dynamics of spontaneous dyadic entrainment, and more specifically how they depend on the sensory modalities mediating informational coupling. By means of a novel interactive paradigm, we showed that dyadic entrainment systematically takes place during a minimalistic rhythmic task despite explicit instructions to ignore the partner. Crucially, the interaction was organized by clear dynamics in a modality-dependent fashion. Our results showed highly consistent coordination patterns in visually-mediated entrainment, whereas we observed more chaotic and more variable profiles in the auditorily-mediated counterpart. The proposed experimental paradigm yields empirical evidence for the overwhelming tendency of dyads to behave as coupled rhythmic units. In the context of our experimental design, it showed that coordination dynamics differ according to availability and nature of perceptual information. Interventions aimed at rehabilitating, teaching or training sensorimotor functions can be ultimately informed and optimized by such fundamental knowledge.

The Use of Analog and Digital Games for Autism Interventions

Many interventions that target improvements in social communication and other cognitive, learning, and physical issues have been developed to help autistic people. The gamification of interventions offers an alternative approach to fostering and assessing desired behaviors and cognitions in a more naturalistic and emergent setting. In this scoping review aimed at educators, practitioners, and parents of those with autism, we detail studies that have tested game-based approaches to improving the lives of autistic children, adolescents, and adults, focusing on how research into gamification and autism can both progress and can be progressed and implemented. We offer parents, professionals and academics resources to incorporate game-based psycho-educational programs into their current practice.

Brief Report: Specificity of Interpersonal Synchrony Deficits to Autism Spectrum Disorder and Its Potential for Digitally Assisted Diagnostics

Reliably diagnosing autism spectrum disorders (ASD) in adulthood poses a challenge to clinicians due to the absence of specific diagnostic markers. This study investigated the potential of interpersonal synchrony (IPS), which has been found to be reduced in ASD, to augment the diagnostic process. IPS was objectively assessed in videos of diagnostic interviews in a representative referral population from two specialized autism outpatient clinics. In contrast to the current screening tools that could not reliably differentiate, we found a significant reduction of IPS in interactions with individuals later diagnosed with ASD (n = 16) as opposed to those not receiving a diagnosis (n = 23). While these findings need to be validated in larger samples, they nevertheless underline the potential of digitally-enhanced diagnostic processes for ASD.

Temporal Synchrony in Autism: a Systematic Review

Temporal synchrony is the alignment of processes in time within or across individuals in social interaction and is observed and studied in various domains using wide-ranging paradigms. Evidence suggesting reduced temporal synchrony in autism (e.g. compared to neurotypicals) has hitherto not been reviewed. To systematically review the magnitude and generalisability of the difference across different tasks and contexts, EBSCO, OVID, Web of Science, and Scopus databases were searched. Thirty-two studies were identified that met our inclusion criteria in audio-visual, audio-motor, visuo-tactile, visuo-motor, social motor, and conversational synchrony domains. Additionally, two intervention studies were included. The findings suggest that autistic participants showed reduced synchrony tendencies in every category of temporal synchrony reviewed. Implications, methodological weaknesses, and evidence gaps are discussed.

The Association among Autistic Traits, Interactional Synchrony and Typical Pattern of Motor Planning and Execution in Neurotypical Individuals

Autism spectrum disorder (ASD) is characterized by deficits in interactional synchrony and motor performance, but little is known about the association between them. The current study investigated the association among aberrant interactional synchrony (as measured by interactors’ symmetry in the form of the hand at each time-point along movement’s execution), motor functioning and the level of Autistic traits. In this study, autistic traits were evaluated by the Autistic Spectrum Quotient (AQ). Two tasks were used: (1) an interactional synchrony task where participants and the research assistant were instructed to move their hands together; and (2) a motor planning task which allows for continuous monitoring of natural hand movements. Pearson correlation analysis indicated a significant association between lower communication skills (i.e., higher AQ communication scores) and lower intentional synchrony rates. In addition, lower communication skills were found associated with typical patterns of motor planning and execution characterized by shorter time to start the movement and higher value of max speed. Mediator analyses supported the notion that aberrant intentional synchrony in individuals with low communication skills is partially mediated through typical patterns of motor planning and execution. These results suggest typical patterns of motor functions may account for intentional synchrony difficulties.

Joint engagement and movement: Active ingredients of a music-based intervention with school-age children with autism

BACKGROUND

The effectiveness of music-based interventions (MI) in autism has been attested for decades. Yet, there has been little empirical investigation of the active ingredients, or processes involved in music-based interventions that differentiate them from other approaches.

OBJECTIVES

Here, we examined whether two processes, joint engagement and movement, which have previously been studied in isolation, contribute as important active ingredients for the efficacy of music-based interventions.

METHODS

In two separate analyses, we investigated whether (1) joint engagement with the therapist, measured using a coding scheme verified for reliability, and (2) movement elicited by music-making, measured using a computer-vision technique for quantifying motion, may drive the benefits previously observed in response to MI (but not a controlled non-MI) in children with autism.

RESULTS

Compared to a non-music control intervention, children and the therapist in MI spent more time in triadic engagement (between child, therapist, and activity) and produced greater movement, with amplitude of motion closely linked to the type of musical instrument.

CONCLUSIONS

Taken together, these findings provide initial evidence of the active ingredients of music-based interventions in autism.

Musical improvisation enhances interpersonal coordination in subsequent conversation: Motor and speech evidence

This study explored the effects of musical improvisation between dyads of same-sex strangers on subsequent behavioural alignment. Participants-all non-musicians-conversed before and after either improvising music together (Musical Improvisation-MI-group) or doing a motoric non-rhythmic cooperative task (building a tower together using wooden blocks; the Hands-Busy-HB-group). Conversations were free, but initially guided by an adaptation of the Fast Friends Questionnaire for inducing talk among students who are strangers and meeting for the first time. Throughout, participants' motion was recorded with an optical motion-capture system (Mocap) and analysed in terms of speed cross-correlations. Their conversations were also recorded on separate channels using headset microphones and were analysed in terms of the periodicity displayed by rhythmic peaks in the turn transitions across question and answer pairs (Q+A pairs). Compared with their first conversations, the MI group in the second conversations showed: (a) a very rapid, partially simultaneous anatomical coordination between 0 and 0.4 s; (b) delayed mirror motoric coordination between 0.8 and 1.5 s; and (c) a higher proportion of Periodic Q+A pairs. In contrast, the HB group's motoric coordination changed slightly in timing but not in degree of coordination between the first and second conversations, and there was no significant change in the proportion of periodic Q+A pairs they produced. These results show a convergent effect of prior musical interaction on joint body movement and use of shared periodicity across speech turn-transitions in conversations, suggesting that interaction in music and speech may be mediated by common processes.

The Potential Role of Dopamine in Mediating Motor Function and Interpersonal Synchrony

Motor functions in general and motor planning in particular are crucial for our ability to synchronize our movements with those of others. To date, these co-occurring functions have been studied separately, and as yet it is unclear whether they share a common biological mechanism. Here, we synthesize disparate recent findings on motor functioning and interpersonal synchrony and propose that these two functions share a common neurobiological mechanism and adhere to the same principles of predictive coding. Critically, we describe the pivotal role of the dopaminergic system in modulating these two distinct functions. We present attention deficit hyperactivity disorder (ADHD) as an example of a disorder that involves the dopaminergic system and describe deficits in motor and interpersonal synchrony. Finally, we suggest possible directions for future studies emphasizing the role of dopamine modulation as a link between social and motor functioning.

Computerized Assessment of Motor Imitation as a Scalable Method for Distinguishing Children With Autism

BACKGROUND

Imitation deficits are prevalent in autism spectrum conditions (ASCs) and are associated with core autistic traits. Imitating others' actions is central to the development of social skills in typically developing populations, as it facilitates social learning and bond formation. We present a Computerized Assessment of Motor Imitation (CAMI) using a brief (1-min), highly engaging video game task.

METHODS

Using Kinect Xbox motion tracking technology, we recorded 48 children (27 with ASCs, 21 typically developing) as they imitated a model's dance movements. We implemented an algorithm based on metric learning and dynamic time warping that automatically detects and evaluates the important joints and returns a score considering spatial position and timing differences between the child and the model. To establish construct validity and reliability, we compared imitation performance measured by the CAMI method to the more traditional human observation coding (HOC) method across repeated trials and two different movement sequences.

RESULTS

Results revealed poorer imitation in children with ASCs than in typically developing children (ps < .005), with poorer imitation being associated with increased core autism symptoms. While strong correlations between the CAMI and HOC methods (rs = .69-.87) confirmed the CAMI's construct validity, CAMI scores classified the children into diagnostic groups better than the HOC scores (accuracyCAMI = 87.2%, accuracyHOC = 74.4%). Finally, by comparing repeated movement trials, we demonstrated high test-retest reliability of CAMI (rs = .73-.86).

CONCLUSIONS

Findings support the CAMI as an objective, highly scalable, directly interpretable method for assessing motor imitation differences, providing a promising biomarker for defining biologically meaningful ASC subtypes and guiding intervention.

Brain and motor synchrony in children and adolescents with ASD-a fNIRS hyperscanning study

Brain-to-brain synchrony has been proposed as an important mechanism underlying social interaction. While first findings indicate that it may be modulated in children with autism spectrum disorder (ASD), no study to date has investigated the influence of different interaction partners and task characteristics. Using functional near-infrared spectroscopy hyperscanning, we assessed brain-to-brain synchrony in 41 male typically developing (TD) children (8-18 years; control sample), as well as 18 children with ASD and age-matched TD children (matched sample), while performing cooperative and competitive tasks with their parents and an adult stranger. Dyads were instructed either to respond jointly in response to a target (cooperation) or to respond faster than the other player (competition). Wavelet coherence was calculated for oxy- and deoxyhemoglobin brain signals. In the control sample, a widespread enhanced coherence was observed for parent-child competition, and a more localized coherence for parent-child cooperation in the frontopolar cortex. While behaviorally, children with ASD showed a lower motor synchrony than children in the TD group, no significant group differences were observed on the neural level. In order to identify biomarkers for typical and atypical social interactions in the long run, more research is needed to investigate the neurobiological underpinnings of reduced synchrony in ASD.

Impairments of interpersonal synchrony evident in attention deficit hyperactivity disorder (ADHD)

In addition to well-known attention deficiencies, attention deficit hyperactivity disorder (ADHD) is accompanied by deficiencies in social cognition. Both intentional and spontaneous interpersonal synchrony have been found to be an essential part of successful human interaction. Here, we used a novel paradigm to assess intentional and spontaneous interpersonal synchrony in adults with and without ADHD. Our data indicate that intentional interpersonal synchrony is reduced in ADHD, whereas spontaneous interpersonal synchrony remains intact. These results suggest that a dysfunctional pattern of interpersonal synchrony may account for interpersonal difficulties in ADHD.

Interactional Synchrony and Its Association with Social and Communication Ability in Children With and Without Autism Spectrum Disorder

Social partners tend to coordinate their behaviors in time. This "interactional synchrony" is associated with a host of positive social outcomes, making it ripe for study in autism spectrum disorder (ASD). Twenty children with ASD and 17 typically developing (TD) children participated in conversations with familiar and unfamiliar adults. Conversations were rated for movement synchrony and verbal synchrony, and mothers completed measures regarding children's everyday social and communication skills. Children with ASD exhibited less interactional synchrony, with familiar and unfamiliar partners, than TD peers. Beyond group-level differences, interactional synchrony negatively correlated with autism symptom severity, and predicted dimensional scores on established social and communication measures. Results suggest that disrupted interactional synchrony may be associated with impaired social functioning in ASD.

Brief Report: Classification of Autistic Traits According to Brain Activity Recoded by fNIRS Using ε-Complexity Coefficients

Individuals with ASD have been shown to have different pattern of functional connectivity. In this study, brain activity of participants with many and few autistic traits, was recorded using an fNIRS device, as participants preformed an interpersonal synchronization task. This type of task involves synchronization and functional connectivity of different brain regions. A novel method for assessing signal complexity, using ε-complexity coefficients, applied for the first i.e. on fNIRS recording, was used to classify brain recording of participants with many/few autistic traits. Successful classification was achieved implying that this method may be useful for classification of fNIRS recordings and that there is a difference in brain activity between participants with low and high autistic traits as they perform an interpersonal synchronization task.

Differences in cortical activation patterns during action observation, action execution, and interpersonal synchrony between children with or without autism spectrum disorder (ASD): An fNIRS pilot study

Engaging in socially embedded actions such as imitation and interpersonal synchrony facilitates relationships with peers and caregivers. Imitation and interpersonal synchrony impairments of children with Autism Spectrum Disorder (ASD) might contribute to their difficulties in connecting and learning from others. Previous fMRI studies investigated cortical activation in children with ASD during finger/hand movement imitation; however, we do not know whether these findings generalize to naturalistic face-to-face imitation/interpersonal synchrony tasks. Using functional near infrared spectroscopy (fNIRS), the current study assessed the cortical activation of children with and without ASD during a face-to-face interpersonal synchrony task. Fourteen children with ASD and 17 typically developing (TD) children completed three conditions: a) Watch-observed an adult clean up blocks; b) Do-cleaned up the blocks on their own; and c) Together-synchronized their block clean up actions to that of an adult. Children with ASD showed lower spatial and temporal synchrony accuracies but intact motor accuracy during the Together/interpersonal synchrony condition. In terms of cortical activation, children with ASD had hypoactivation in the middle and inferior frontal gyri (MIFG) as well as middle and superior temporal gyri (MSTG) while showing hyperactivation in the inferior parietal cortices/lobule (IPL) compared to the TD children. During the Together condition, the TD children showed bilaterally symmetrical activation whereas children with ASD showed more left-lateralized activation over MIFG and right-lateralized activation over MSTG. Additionally, using ADOS scores, in children with ASD greater social affect impairment was associated with lower activation in the left MIFG and more repetitive behavior impairment was associated with greater activation over bilateral MSTG. In children with ASD better communication performance on the VABS was associated with greater MIFG and/or MSTG activation. We identified objective neural biomarkers that could be utilized as outcome predictors or treatment response indicators in future intervention studies.

Herding in human groups is related to high autistic traits

Herding is ubiquitous throughout all social life forms, providing beneficial outcomes. Here, we examine whether herding emerges spontaneously in human groups and whether it adheres to the core principles of herding observed in the animal kingdom. Using a computerized paradigm involving the movements of circles, we tested the emergence of spontaneous and intentional herding of 136 participants assigned into groups of four participants. Herding was assessed by measuring directional synchrony in the movements of the circles, level of cohesion, and separation between circles. We found that human groups tend to spontaneously herd, particularly in terms of directional synchrony, supporting the notion of a human herding instinct. We further asked whether individuals with high traits of Autism Spectrum Disorder (ASD) exhibit differences in their herding tendencies. Results indicated that individuals with high ASD traits showed greater social separation from the group, compared to individuals with low ASD traits. Moreover, we found diminished spontaneous synchrony, but intact instructed synchrony in the high vs. the low ASD traits group. We contend that humans spontaneously herd with their group and suggest that the spontaneous tendency to synchronize with others is diminished in individuals with high ASD traits, though it is recovered when synchronization is intentional.