Rocking together: dynamics of intentional and unintentional interpersonal coordination

Can social interaction constitute social cognition?

An important shift is taking place in social cognition research, away from a focus on the individual mind and toward embodied and participatory aspects of social understanding. Empirical results already imply that social cognition is not reducible to the workings of individual cognitive mechanisms. To galvanize this interactive turn, we provide an operational definition of social interaction and distinguish the different explanatory roles - contextual, enabling and constitutive - it can play in social cognition. We show that interactive processes are more than a context for social cognition: they can complement and even replace individual mechanisms. This new explanatory power of social interaction can push the field forward by expanding the possibilities of scientific explanation beyond the individual.

Stability and variability of acoustically specified coordination patterns while walking side-by-side on a treadmill: does the seagull effect hold?

To examine whether the Haken-Kelso-Bunz model for rhythmic interlimb coordination applies to walking side-by-side on a treadmill, we invited six pairs of participants to coordinate their stepping movements at seven prescribed relative phases (between 0 degrees and 180 degrees ) to scan the attractor layout governing their coordination. Two auditory metronomes, one for each participant, specified the required relative phase. For each trial participants were instructed to synchronize their left heel strikes with the beeps of the metronome (2min) and to continue walking after the metronome stopped (1min). If the Haken-Kelso-Bunz model applies to interpersonal coordination during treadmill walking, then (1) the variability of in- and antiphase should be minimal, (2) intermediate relative phases should be attracted to either in- or antiphase, and (3) the absolute shift away from the required relative phase should be greatest for a required relative phase of 90 degrees . Only the third of these hypotheses was confirmed, indicating that the dynamical model for rhythmic interlimb coordination does not readily apply, at least not generically or robustly, to interpersonal coordination during walking side-by-side on a treadmill.

Interpersonal pattern dynamics and adaptive behavior in multiagent neurobiological systems: conceptual model and data

Ecological dynamics characterizes adaptive behavior as an emergent, self-organizing property of interpersonal interactions in complex social systems. The authors conceptualize and investigate constraints on dynamics of decisions and actions in the multiagent system of team sports. They studied coadaptive interpersonal dynamics in rugby union to model potential control parameter and collective variable relations in attacker-defender dyads. A videogrammetry analysis revealed how some agents generated fluctuations by adapting displacement velocity to create phase transitions and destabilize dyadic subsystems near the try line. Agent interpersonal dynamics exhibited characteristics of chaotic attractors and informational constraints of rugby union boxed dyadic systems into a low dimensional attractor. Data suggests that decisions and actions of agents in sports teams may be characterized as emergent, self-organizing properties, governed by laws of dynamical systems at the ecological scale. Further research needs to generalize this conceptual model of adaptive behavior in performance to other multiagent populations.

Nonlinear time series analysis of knee and ankle kinematics during side by side treadmill walking

Nonlinear time series analysis was used to estimate maximal Lyapunov exponents of select ankle and knee kinematics during three different conditions of treadmill walking: independent, side by side, and side by side with forced synchronization of stepping. Stride to stride variability was significantly increased for the condition in which individuals walked side by side and synchronized unintentionally when compared to the conditions of forced synchronization and independent walking. In addition, standard deviations of three kinematic variables of lower extremity movement were significantly increased during the condition in which unintentional synchronization occurred. No relationship was found between standard deviation and estimates of maximal Lyapunov exponents. An increase in kinematic variability during side by side walking for nonimpaired individuals who are not at risk of falling suggests that variability in certain aspects of performance might be indicative of a healthy system. Modeling this variability for an impaired individual to imitate may have beneficial effects on locomotor function. These results may therefore have implications for the rehabilitation of gait in humans by suggesting that a different functional outcome might be achieved by practicing side by side walking as opposed to more commonly used strategies involving independent walking.

Evolving intentions for social interaction: from entrainment to joint action

This article discusses four different scenarios to specify increasingly complex mechanisms that enable increasingly flexible social interactions. The key dimension on which these mechanisms differ is the extent to which organisms are able to process other organisms' intentions and to keep them apart from their own. Drawing on findings from ecological psychology, scenario 1 focuses on entrainment and simultaneous affordance in 'intentionally blind' individuals. Scenario 2 discusses how an interface between perception and action allows observers to simulate intentional action in others. Scenario 3 is concerned with shared perceptions, arising through joint attention and the ability to distinguish between self and other. Scenario 4 illustrates how people could form intentions to act together while simultaneously distinguishing between their own and the other's part of a joint action. The final part focuses on how combining the functionality of the four mechanisms can explain different forms of social interactions. It is proposed that basic interpersonal processes are put to service by more advanced functions that support the type of intentionality required to engage in joint action, cultural learning, and communication.

Neuroimaging coordination dynamics in the sport sciences

Key methodological issues for designing, analyzing, and interpreting neuroimaging experiments are presented from the perspective of the framework of Coordination Dynamics. To this end, a brief overview of Coordination Dynamics is introduced, including the main concepts of control parameters and collective variables, theoretical modeling, novel experimental paradigms, and cardinal empirical findings. Basic conceptual and methodological issues for the design and implementation of coordination experiments in the context of neuroimaging are discussed. The paper concludes with a presentation of neuroimaging findings central to understanding the neural basis of coordination and addresses their relevance for the sport sciences. The latter include but are not restricted to learning and practice-related issues, the role of mental imagery, and the recovery of function following brain injury.

Entrainment of syntactic processing? ERP-responses to predictable time intervals during syntactic reanalysis

Synchronization of two independent systems is a widely discussed phenomenon observed in many disciplines. Recent studies have shown its relevance to cognitive functions. However, its influence on language perception has not yet been investigated. As successful syntactic processing relies on rules that enable the listener to predict the category of the next incoming element, such prediction can be maximized if the auditory speech input is temporally regular and hence motivates synchronization. For this reason, the present ERP-experiments investigated the influence of successful synchronization in auditory syntactic processing. Our results clearly demonstrate that late syntactic processes (P600) are controlled by a temporally regular input. In particular, the latency of the P600 varies as a function of the duration of a pre-determined interval between successive elements. The current data therefore attest the impact of synchronization on higher level cognitive processes such as syntax in language.

Comparing the attractor strength of intra- and interpersonal interlimb coordination using cross-recurrence analysis

Previous research has demonstrated that intra- and interpersonal rhythmic interlimb coordination are both constrained by the self-organizing entrainment process of coupled oscillators. Despite intra- and interpersonal coordination exhibiting the same stable macroscopic movement patterns the variability of the coordination is typically found to be much greater for inter- compared to intrapersonal coordination. Researchers have assumed that this is due to the interpersonal visual-motor coupling producing a weaker attractor dynamic than the intrapersonal neuromuscular coupling. To determine whether this assumption is true, two experiments were conducted in which pairs of participants coordinated hand-held pendulums swung about the wrist, either intra- and interpersonally. Using the cross-recurrence statistics of percent recurrence and maxline to independently index the level of noise and the attractor strength of the coordination, respectively, the results confirmed that the attractor strength was significantly weaker for inter- compared to intrapersonal coordination and that a similar magnitude of noise underlies both.