Veronica Romero

Movement coordination or movement interference: visual tracking and spontaneous coordination modulate rhythmic movement interference.

When an actor performs a rhythmic limb movement while observing a spatially incongruent movement he or she exhibits increased movement orthogonal to the instructed motion. Known as rhythmic movement interference, this phenomenon has been interpreted as a motor contagion effect, whereby observing the incongruent movement interferes with the intended movement and results in a motor production error. Here we test the hypothesis that rhythmic movement interference is an emergent property of rhythmic coordination. Participants performed rhythmic limb movements at a self-selected tempo while observing a computer stimulus moving in a congruent or incongruent manner. The degree to which participants visually tracked the stimulus was manipulated to influence whether participants became spontaneously entrained to the stimulus or not. Consistent with the rhythmic coordination hypothesis, participants only exhibited the rhythmic movement interference effect when they became spontaneously entrained to the incongruent stimulus.

Visual Multifrequency Entrainment: Can 1:2, 2:3, and 3:4 Coordination Occur Spontaneously?

ABSTRACT. Complex patterns of interlimb coordination, such as multifrequency relationships of 1:2, 2:3, or 3:4, are difficult to perform intentionally without extensive practice. The current study investigated whether these patterns might nonetheless occur spontaneously given an appropriate balance between the movement frequencies, or oscillatory periods, of an individuals movements and a visual-environmental stimulus. In order to test this, participants swung a fixed-period wrist-pendulum while observing an oscillating computer-generated stimulus. Results indicated that at given differences in period, 1:2, 2:3, and 3:4 coordination patterns emerged between the participant and stimulus. This suggests that large period differences do not altogether prevent the emergence of rhythmic visuomotor coordination, but instead provide the opportunity for complex patterns of coordination to emerge spontaneously.

Can Discrete Joint Action Be Synergistic? Studying the Stabilization of Interpersonal Hand Coordination

The human perceptual-motor system is tightly coupled to the physical and informational dynamics of a task environment. These dynamics operate to constrain the high-dimensional order of the human movement system into low-dimensional, task-specific synergies-functional groupings of structural elements that are temporarily constrained to act as a single coordinated unit. The aim of the current study was to determine whether synergistic processes operate when coacting individuals coordinate to perform a discrete joint-action task. Pairs of participants sat next to each other and each used 1 arm to complete a pointer-to-target task. Using the uncontrolled manifold (UCM) analysis for the first time in a discrete joint action, the structure of joint-angle variance was examined to determine whether there was synergistic organization of the degrees of freedom employed at the interpersonal or intrapersonal levels. The results revealed that the motor actions performed by coactors were synergistically organized at both the interpersonal and intrapersonal levels. More importantly, however, the interpersonal synergy was found to be significantly stronger than the intrapersonal synergies. Accordingly, the results provide clear evidence that coacting individuals can become temporarily organized to form single synergistic 2-person systems during performance of a discrete joint action.

Social Motor Synchronization: Insights for Understanding Social Behavior in Autism

Impairments in social interaction and communication are critical features of ASD but the underlying processes are poorly understood. An under-explored area is the social motor synchronization that happens when we coordinate our bodies with others. Here, we explored the relationships between dynamical measures of social motor synchronization and assessments of ASD traits. We found (a) spontaneous social motor synchronization was associated with responding to joint attention, cooperation, and theory of mind while intentional social motor synchronization was associated with initiating joint attention and theory of mind; and (b) social motor synchronization was associated with ASD severity but not fully explained by motor problems. Findings suggest that objective measures of social motor synchronization may provide insights into understanding ASD traits.

Evaluating the importance of social motor synchronization and motor skill for understanding autism

Impairments in social interaction and communicating with others are core features of autism spectrum disorder (ASD), but the specific processes underlying such social competence impairments are not well understood. An important key for increasing our understanding of ASD‐specific social deficits may lie with the social motor synchronization that takes place when we implicitly coordinate our bodies with others. Here, we tested whether dynamical measures of synchronization differentiate children with ASD from controls and further explored the relationships between synchronization ability and motor control problems. We found (a) that children with ASD exhibited different and less stable patterns of social synchronization ability than controls; (b) children with ASD performed motor movements that were slower and more variable in both spacing and timing; and (c) some social synchronization that involved motor timing was related to motor ability but less rhythmic synchronization was not. These findings raise the possibility that objective dynamical measures of synchronization ability and motor skill could provide new insights into understanding the social deficits in ASD that could ultimately aid clinical diagnosis and prognosis. Autism Res 2017, 10: 1687–1699.

Using Cross-Recurrence Quantification Analysis to Understand Social Motor Coordination in Children with Autism Spectrum Disorder

Interpersonal motor coordination is considered to be an integral part of maintaining successful social interactions. Research has shown that simply coordinating one’s movements with another actor can influence rapport as well as feelings of social connection and social competence. Past research has also found that deficits in social motor coordination are associated with psychological dysfunction such as schizophrenia and borderline personality disorders. However, the potential association between interpersonal motor coordination and autism spectrum disorder (ASD) has only received a very limited amount of attention. In the current experiment, children who had been previously diagnosed with ASD and typically developing (TD) children were asked to synchronize with or imitate the movements of an experimenter in two different interpersonal motor tasks: object tapping and hand-clapping. Both the experimenter’s and the participants’ movements were captured and compared to each other using relative phase analysis and cross-recurrence quantification analysis (CRQA). The results reveal differences not only in the patterning of the coordination that occurred for ASD and TD children, but also in the stability and deterministic structure of the coordination. Of particular interest was the finding that children with ASD exhibited less stable (robust), but more deterministic patterns of interpersonal social motor coordination compared to TD children.

Can low-cost motion-tracking systems substitute a Polhemus system when researching social motor coordination in children?

Functionally stable and robust interpersonal motor coordination has been found to play an integral role in the effectiveness of social interactions. However, the motion-tracking equipment required to record and objectively measure the dynamic limb and body movements during social interaction has been very costly, cumbersome, and impractical within a non-clinical or non-laboratory setting. Here we examined whether three low-cost motion-tracking options (Microsoft Kinect skeletal tracking of either one limb or whole body and a video-based pixel change method) can be employed to investigate social motor coordination. Of particular interest was the degree to which these low-cost methods of motion tracking could be used to capture and index the coordination dynamics that occurred between a child and an experimenter for three simple social motor coordination tasks in comparison to a more expensive, laboratory-grade motion-tracking system (i.e., a Polhemus Latus system). Overall, the results demonstrated that these low-cost systems cannot substitute the Polhemus system in some tasks. However, the lower-cost Microsoft Kinect skeletal tracking and video pixel change methods were successfully able to index differences in social motor coordination in tasks that involved larger-scale, naturalistic whole body movements, which can be cumbersome and expensive to record with a Polhemus. However, we found the Kinect to be particularly vulnerable to occlusion and the pixel change method to movements that cross the video frame midline. Therefore, particular care needs to be taken in choosing the motion-tracking system that is best suited for the particular research.

Interaction between intention and environmental constraints on the fractal dynamics of human performance

Abstract The current study investigated whether the influence of available task constraints on power-law scaling might be moderated by a participant’s task intention. Participants performed a simple rhythmic movement task with the intention of controlling either movement period or amplitude, either with or without an experimental stimulus designed to constrain period. In the absence of the stimulus, differences in intention did not produce any changes in power-law scaling. When the stimulus was present, however, a shift toward more random fluctuations occurred in the corresponding task dimension, regardless of participants’ intentions. More importantly, participants’ intentions interacted with available task constraints to produce an even greater shift toward random variation when the task dimension constrained by the stimulus was also the dimension the participant intended to control. Together, the results suggest that intentions serve to more tightly constrain behavior to existing environmental constraints, evidenced by changes in the fractal scaling of task performance.

Evidence of embodied social competence during conversation in high functioning children with autism spectrum disorder

Even high functioning children with Autism Spectrum Disorder (ASD) exhibit impairments that affect their ability to carry out and maintain effective social interactions in multiple contexts. One aspect of subtle nonverbal communication that might play a role in this impairment is the whole-body motor coordination that naturally arises between people during conversation. The current study aimed to measure the time-dependent, coordinated whole-body movements between children with ASD and a clinician during a conversational exchange using tools of nonlinear dynamics. Given the influence that subtle interpersonal coordination has on social interaction feelings, we expected there to be important associations between the dynamic motor movement measures introduced in the current study and the measures used traditionally to categorize ASD impairment (ADOS-2, joint attention and theory of mind). The study found that children with ASD coordinated their bodily movements with a clinician, that these movements were complex and that the complexity of the children’s movements matched that of the clinician’s movements. Importantly, the degree of this bodily coordination was related to higher social cognitive ability. This suggests children with ASD are embodying some degree of social competence during conversations. This study demonstrates the importance of further investigating the subtle but important bodily movement coordination that occurs during social interaction in children with ASD.

Understanding the Influence of Social and Motor Context on the Co-occurring Frequency of Restricted and Repetitive Behaviors in Autism

The social and motor context in which restricted and repetitive behaviors (RRBs) occur in autism and their relationship to social traits are not well-understood. Participants with and without autism completed tasks that varied in social and motor engagement and RRB frequency was measured. Motor and verbal RRBs were most common, RRBs varied based on motor and social context for participants with autism, and social engagement was associated with lower motor and verbal RRBs. Significant correlations between RRBs and autism severity, social synchrony, and nonverbal mental age were also found. This research confirms the importance of context for understanding RRBs during on-going tasks and raises questions about whether the factors that elicit vocal and motor RRBs are unique for individual children.