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A Comparison of Intra- and Interpersonal Interlimb Coordination: Coordination Breakdowns and Coupling Strength
Abstract and Figures
Intra- and interpersonal interlimb coordination of pendulums swung from the wrist was investigated. For both kinds of coordination, the steady state and breakdown of bimanual rhythmic coordination as indexed by the time series of the relative phase angle phi were studied under the manipulation of coordination mode, frequency of oscillation, and the difference in the eigenfrequencies (preferred tempos) of the individual oscillating limbs. The properties observed for both intra- and interpersonal coordination were those predicted by a dynamical model of rhythmic coordination that considers the coordinated limbs coupled to be nonlinear oscillators. Using a regression method, the coupling strengths of the coupled system were recovered. As predicted by the dynamical model, the strength of the dynamic was generally greater for the in-phase than the anti-phase mode and decreased with increasing frequency. Further, the strength of the interpersonal interlimb coupling was weaker than that of intrapersonal interlimb coupling.
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... Experiment 1 examined the validity of the rocking chair paradigm for the study of intentional coordination by having participants coordinate rocking chairs inphase (φ = 0˚) or antiphase (φ = 180˚) under three different magnitudes of detuning (∆ω). It was expected that the patterns of interpersonal coordination would be consistent with a coupled oscillator dynamic, such that: (1) inphase would be more stable (less variable) than antiphase; (2) ∆ω ≠ 0 would result in a phase shift that would be (3) more pronounced for antiphase than for inphase, and (4) the variability of relative phase would be greater for ∆ω ≠ 0 than for ∆ω = 0 (Schmidt & Turvey, 1994;Schmidt et al., 1998). ...
... Overall, the results are consistent with previous research using a wristpendulum paradigm to study interpersonal coordination (Schmidt & Turvey, 1994, Schmidt & O'Brien, 1997Schmidt et al., 1998) and provide further evi- dence that such coordination is constrained in accordance with a coupled oscillator dynamic. Moreover, the data establish the efficacy and ecological validity of the rocking chair paradigm for the study of interpersonal coordination. ...
... The behavioral characteristics of leaders and followers in such joint motor actions may manifest in task-specific ways. In some movement tasks, the leader temporally leads the actions, while the follower lags behind [5][6][7][8][9][10] . In other tasks, the leader may exhibit less movement variability to increase the predictability of their actions for the follower 11,12 when the follower was explicitly tasked to coordinate with the movement of the assigned leader. ...
... Following a systematic exploration of the solution space, the experimental conditions characterized by haptic feedback (S400 and S200) led dyads to co-adapt and converge to similar solutions whereby one of the agents' (left) movement spatio-temporally led the other agent's (right) movement (Fig. 3). These asymmetrical contributions suggest that role specialization occurred where the left agent assumed the leader's role according to the common lead-lag definition of leaders in joint motor tasks [5][6][7][8] . Moreover, the left agent also exerted greater force and exhibited more corrective forces than the right agent (Fig. 4), which is consistent with the force-based role specialization found in some of the previous studies 9, 13,14 . ...
Are leaders made or born? Leader–follower roles have been well characterized in social science, but they remain somewhat obscure in sensory-motor coordination. Furthermore, it is unknown how and why leader–follower relationships are acquired, including innate versus acquired controversies. We developed a novel asymmetrical coordination task in which two participants (dyad) need to collaborate in transporting a simulated beam while maintaining its horizontal attitude. This experimental paradigm was implemented by twin robotic manipulanda, simulated beam dynamics, haptic interactions, and a projection screen. Clear leader–follower relationships were learned only when strong haptic feedback was introduced. This phenomenon occurred despite participants not being informed that they were interacting with each other and the large number of equally-valid alternative dyadic coordination strategies. We demonstrate the emergence of consistent leader–follower relationships in sensory-motor coordination, and further show that haptic interaction is essential for dyadic co-adaptation. These results provide insights into neural mechanisms responsible for the formation of leader–follower relationships in our society.
... According to della Gatta et al., this suggests that participants represented the joint goal (drawing a circle and a line) motorically, almost as if they were performing the two actions with their own two hands. Thus, the intrapersonal motor coupling typically observed in bimanual coordination (Franz et al., 1991) emerged here in the form of interpersonal coupling (consistent with the account that coordination within and between individuals relies on similar processes (e.g., Fine & Amazeen, 2011;Richardson et al., 2007;Schmidt et al., 1998;Schmidt & Richardson, 2008)). ...
When acting jointly, individuals often attend and respond to the same object or spatial location in complementary ways (e.g., when passing a mug, one person grasps its handle with a precision grip; the other receives it with a whole-hand grip). At the same time, the spatial relation between individuals’ actions affects attentional orienting: one is slower to attend and respond to locations another person previously acted upon than to alternate locations (“social inhibition of return”, social IOR). Achieving joint goals (e.g., passing a mug), however, often requires complementary return responses to a co-actor’s previous location. This raises the question of whether attentional orienting, and hence the social IOR, is affected by the (joint) goal our actions are directed at. The present study addresses this question. Participants responded to cued locations on a computer screen, taking turns with a virtual co-actor. They pursued either an individual goal or performed complementary actions with the co-actor, in pursuit of a joint goal. Four experiments showed that the social IOR was significantly modulated when participant and co-actor pursued a joint goal. This suggests that attentional orienting is affected not only by the spatial but also by the social relation between two agents’ actions. Our findings thus extend research on interpersonal perception-action effects, showing that the way another agent’s perceived action shapes our own depends on whether we share a joint goal with that agent.
... tion ( Camazine et al., 2003 ;Pezzulo et al., 2019 ). As such, INS would be reminiscent of many other self-organized entrainment phenomena observed across very heterogeneous fields of research, including psychology ( Oullier et al., 2008 ;Richardson et al., 2007Richardson et al., , 2005Schmidt et al., 1998 ;Varlet et al., 2017 ), ethology ( Ballerini et al., 2008 ;Buhl et al., 2006 ;Cavagna et al., 2010 ;Couzin, 2007 ;Yates et al., 2009 ), or even physics ( Peña Ramirez et al., 2016 ;Von Humboldt, 1846 ). For instance, INS might be qualitatively similar to the spontaneous synchronization of behavioral states in multiple collective animal behavior like flocking in birds ( Ballerini et al., 2008 ), or swarms of insects ( Yates et al., 2009 ). ...
Synchronization of neural activity across brains - interpersonal neural synchrony (INS) - is emerging as a powerful marker of social interaction that predicts success of multi-person coordination, communication, and cooperation. As the origins of INS are poorly understood, we tested whether and how INS might emerge from spontaneous dyadic behavior. We recorded neural activity (EEG) and human behavior (full-body kinematics, eye movements and facial expressions) while dyads of participants were instructed to look at each other without speaking or making co-verbal gestures. We made four fundamental observations. First, despite the absence of a structured social task, INS emerged spontaneously only when participants were able to see each other. Second, we show that such spontaneous INS, comprising specific spectral and topographic profiles, did not merely reflect intra-personal modulations of neural activity, but it rather reflected real-time and dyad-specific coupling of neural activities. Third, using state-of-art video-image processing and deep learning, we extracted the temporal unfolding of three notable social behavioral cues - body movement, eye contact, and smiling - and demonstrated that these behaviors also spontaneously synchronized within dyads. Fourth, we probed the correlates of INS in such synchronized social behaviors. Using cross-correlation and Granger causality analyses, we show that synchronized social behaviors anticipate and in fact Granger cause INS. These results provide proof-of-concept evidence for studying interpersonal neural and behavioral synchrony under natural and unconstrained conditions. Most importantly, the results suggest that INS could be conceptualized as an emergent property of two coupled neural systems: an entrainment phenomenon, promoted by real-time dyadic behavior.
... Individuals appear to rely on prediction in order to maintain a certain tempo during joint tapping because individuals depend on an anticipatory mechanism to achieve good synchrony [41][42] [43]. Performing fast antiphase tapping would require each participant to accurately predict the behavior of their partner to keep a constant tempo because anti-phase tapping tends to become unstable (high SDRP) at a fast tempo, which similarly occurs during bimanual coordination [12] [44]. In contrast, it is easy for participants to keep anti-phase tapping at a slow tempo (slow, free, and pseudo conditions), which therefore requires less prediction between partners. ...
Inter-brain synchronization is enhanced when individuals perform rhythmic interpersonal coordination tasks, such as playing instruments in music ensembles. Experimentally, synchronization has been shown to correlate with the performance of joint tapping tasks. However, it is unclear whether inter-brain synchronization is related to the stability of interpersonal coordination represented as the standard deviation of relative phase (SDRP). In this study, we simultaneously recorded electroencephalograms of two paired individuals during anti-phase tapping in three speed conditions: slow (reference inter-tap interval [ITI]: 0.5 s), fast (reference ITI: 0.25 s), and free (preferred ITI). We calculated the inter-brain synchronization within six regions of interest: frontal, central, left/right temporal, parietal, and occipital regions. We found that synchronization of the central-temporal regions was positively correlated with SDRP in the theta and alpha bands, while synchronization of the frontal-frontal and frontal-central was positively correlated with SDRP in the beta band. These results demonstrate that inter-brain synchronization occurs only when task requirements are high, and that it increases with the instability of the coordination. This may be explained by the stronger mutual prediction required in unstable coordination than that in stable coordination, which increases inter-brain synchronization.
... Research on collective tasks showed that when sharing visual information on their performance, group members tend to coordinate their forces and movements [36,39,40]. Hence, the visual feedback could have an impact on the muscular effort variability between dyads, as well as between participants within each dyad. ...
Team lifting is a complex and collective motor task comprising motor and cognitive components. The purpose of this research is to investigate how individual and collective performances are impacted during load transport combined with a cognitive task. Ten dyads performed a first condition in which they transported a load (CC), and a second one in which they transported the load while maintaining a ball on its top (PC). The recovery-rate, amplitude and period of the centre-of-mass (COM) trajectory were computed for the system (dyad + table = PACS). We analysed the forces and moments exerted at each joint of the upper limbs of the participants. We observed a decrease in the overall performance of the dyads during PC: (i) the velocity and amplitude of CoMPACS decreased by 1.7% and 5.8%, respectively, (ii) inter-participant variability of the Moment-Cost-Function and recovery rate decreased by 95%, and 19.2%, respectively during PC. Kinetic synergy analysis showed that the participants reorganized their coordination in the PC. We demonstrated that adding a precision task affects the economy of collective load carriage at the PACS level while the upper-limbs joint moments were better balanced across the paired participants for the PC.
... Phase synchrony, then, represents the relation between phase angles of two oscillating systems that are coupled. In the case of interpersonal synchrony, coupling refers to an interdependent relationship facilitated through a shared visual or auditory space (Oullier et al., 2008;Schmidt et al., 1998). It has been shown that once in action, coupled systems stabilize to either an in-phase (same phase angle) or anti-phase (opposite angles, e.g., 0° and 180°) angle, and remain in this state robustly (Schmidt et al., 1990). ...
Interpersonal synchrony serves as a subtle, yet powerful bonding mechanism in social interactions. Problematically, the term ‘synchrony’ has been used to label a variety of distinct aspects of interpersonal coordination, such as postural similarities or movement activity entrainment. Accordingly, different algorithms have been suggested to quantify interpersonal synchrony. Yet, it remains unknown whether the different measures of synchrony represent correlated features of the same perceivable core phenomenon. The current study addresses this by comparing the suitability of a set of algorithms with respect to their association with observers’ judgments of dyadic synchrony and leader-followership. One-hundred fifteen observers viewed computer animations of characters portraying the movements of real dyads who performed a repetitive motor task with instruction to move in unison. Animations were based on full-body motion capture data synchronously collected for both partners during the joint exercise. Results showed most synchrony measures significantly correlated with (a) perceived synchrony and (b) the perceived level of balance of leading/following by each dyad member. Phase synchrony and Pearson correlations were associated most strongly with the observer ratings. This might be typical for intentional, structured forms synchrony such as ritualized group activities. It remains open if these findings also apply to spontaneous forms of synchrony as, for instance, occurring in free-running conversations.
Movements are naturally composed of submovements, i.e. recurrent speed pulses (2–3 Hz), possibly reflecting intermittent feedback-based motor adjustments. In visuomotor (unimanual) synchronization tasks, partners alternate submovements over time, indicating mutual coregulation. However, it is unclear whether submovement coordination is organized differently between and within individuals. Indeed, different types of information may be variably exploited for intrapersonal and interpersonal coordination. Participants performed a series of bimanual tasks alone or in pairs, with or without visual feedback (solo task only). We analysed the relative timing of submovements between their own hands or between their own hands and those of their partner. Distinct coordinative structures emerged at the submovement level depending on the relevance of visual feedback. Specifically, the relative timing of submovements (between partners/effectors) shifts from alternation to simultaneity and a mixture of both when coordination is achieved using vision (interpersonal), proprioception/efference-copy only (intrapersonal, without vision) or all information sources (intrapersonal, with vision), respectively. These results suggest that submovement coordination represents a behavioural proxy for the adaptive weighting of different sources of information within action-perception loops. In sum, the microstructure of movement reveals common principles governing the dynamics of sensorimotor control to achieve both intra- and interpersonal coordination.
Socially situated thought and behaviour are pervasive and vitally important in human society. The social brain has become a focus of study for researchers in the neurosciences, psychology, biology and other areas of behavioural science, and it is becoming increasingly clear that social behaviour is heavily dependent on shared representations. Any social activity, from a simple conversation to a well-drilled military exercise to an exquisitely perfected dance routine, involves information sharing between the brains of those involved. This volume comprises a collection of cutting-edge essays centred on the idea of shared representations, broadly defined. Featuring contributions from established world leaders in their fields and written in a simultaneously accessible and detailed style, this is an invaluable resource for established researchers and those who are new to the field.
Social behaviors rely on the coordination of multiple effectors within one’s own body as well as between the interacting bodies. However, little is known about how coupling at the interpersonal level impacts coordination among body parts at the intrapersonal level, especially in ecological, complex, situations. Here, we perturbed interpersonal sensorimotor communication in violin players of an orchestra and investigated how this impacted musicians’ intrapersonal movements coordination. More precisely, first section violinists were asked to turn their back to the conductor and to face the second section of violinists, who still faced the conductor. Motion capture of head and bow kinematics showed that altering the usual interpersonal coupling scheme increased intrapersonal coordination. Our perturbation also induced smaller yet more complex head movements, which spanned multiple, faster timescales that closely matched the metrical levels of the musical score. Importantly, perturbation differentially increased intrapersonal coordination across these timescales. We interpret this behavioral shift as a sensorimotor strategy that exploits periodical movements to effectively tune sensory processing in time and allows coping with the disruption in the interpersonal coupling scheme. As such, head movements, which are usually deemed to fulfill communicative functions, may possibly be adapted to help regulate own performance in time.
In this paper we pursue the argument that where a group of muscles functions as a single unit the resulting coordinative structure, to a first approximation, exhibits behavior qualitatively like that of a force-driven mass-spring system. Data are presented illustrating the generative and context-independent characteristics of this system in tasks that require animals and humans to produce accurate limb movements in spite of unpredictable changes in initial conditions, perturbations during the movement and functional deafferentation. Analogous findings come from studies of articulatory compensation in speech production. Finally we provide evidence suggesting that one classically-defined source of information for movement, namely proprioception, may not be dimension-specific in its contribution to coordination and control.
Between-person visual coordination of rhythmic limb movements was investigated under manipulation of both social and physical variables. Each member of a pair of participants oscillated a hand-held pendulum at the same tempo, with both visually coordinating their movements so as to maintain the alternate phase mode. Participants' social competence was assessed and they were paired to produce three types of combinations: high-high (HH), low-low (LL), and high-low (HL). The frequency of oscillation (set by a metronome) and the preferred frequency differ- ence of the pendulum combinations (set by changing the relative lengths of the pendulums to be coordinated) were manipulated. Mean relative phase angle 4 and its variability were measured as indices of coordination. Standard results from interlimb coordination were replicated in the manipulation of the physical vari- ables: (a) More breakdowns in phase locking (defined as mean 4s outside the stable 130 deg. to 230 deg. range) were observed for the higher frequency of oscillation, (b) Relative phase lag changed proportionately with absolute difference in the pre- ferred frequency of the individual pendulums. Further, anomalous 4 standard- deviation results seemed to indicate a second source of fluctuations being caused by strong nonlinearities at the level of the component rhythmic units. Impor- tantly, the coordination was also affected by the social competence manipulations: HH and LL pairs demonstrated more breakdowns in phase locking than did the HL pair.
Human handedness was investigated in a 1:1 interlimb rhythmic coordination in which consistent and inconsistent left-handed and right-handed individuals oscillated hand-held pendulums. Mean phase difference (φ
stable) and its standard deviation (
SDφ) were evaluated as functions of mode of coordination (in-phase vs anti-phase) and the symmetry conditions imposed by controlling the natural frequencies of the left and right pendulums. The dependencies of φ
stable and
SDφ on coordination mode and imposed symmetry were found to be systematically affected by handedness. The data were consistent with an elaboration of the established order parameter dynamics of interlimb rhythmic coordination. The elaboration includes additional 27π periodic terms that break the symmetry of those dynamics when the natural frequencies of the component rhythmic units are identical. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
Synergetic phase transitions afford a special window into the principles of behavior at several levels of desciption. The reason is that instabilities serve to demarcate behavioral patterns, thereby allowing a precise identification of collective variables or order parameters for patterns and their (nonlinear) dynamics. Once the, order parameter dynamics are known for particular experimental model systems, not only can they be derived or synthesized, but a number of steps of generalization becomes possible. Certain essential psychological functions such as the perception of dynamic visual and speech patterns, intentional behavioral change and learning a novel behavioral pattern are addressed here. All observed phenomena may be expressed in dynamical language.
review the evidence of the existence of . . . high-level programs, functioning as localized "unifying structures" for bimanual movements, and in particular . . . restate the question in terms of localization / [address] the problem of whether specific cortical areas are responsible for temporal and spatial coupling of both hands when they are engaged in purposeful cooperative manipulations, as is so often the case in the natural movement repertoire of primates / [develop] a bimanual task in order to learn more about the possible role of the SMA [supplementary motor area] in controlling the precise temporal and spatial coordination in [monkeys] (PsycINFO Database Record (c) 2012 APA, all rights reserved)