Ashley Walton

Improvisation and the self-organization of multiple musical bodies

Understanding everyday behavior relies heavily upon understanding our ability to improvise, how we are able to continuously anticipate and adapt in order to coordinate with our environment and others. Here we consider the ability of musicians to improvise, where they must spontaneously coordinate their actions with co-performers in order to produce novel musical expressions. Investigations of this behavior have traditionally focused on describing the organization of cognitive structures. The focus, here, however, is on the ability of the time-evolving patterns of inter-musician movement coordination as revealed by the mathematical tools of complex dynamical systems to provide a new understanding of what potentiates the novelty of spontaneous musical action. We demonstrate this approach through the application of cross wavelet spectral analysis, which isolates the strength and patterning of the behavioral coordination that occurs between improvising musicians across a range of nested time-scales. Revealing the sophistication of the previously unexplored dynamics of movement coordination between improvising musicians is an important step toward understanding how creative musical expressions emerge from the spontaneous coordination of multiple musical bodies.

Self-organized complementary joint action: Behavioral dynamics of an interpersonal collision-avoidance task.

Understanding stable patterns of interpersonal movement coordination is essential to understanding successful social interaction and activity (i.e., joint action). Previous research investigating such coordination has primarily focused on the synchronization of simple rhythmic movements (e.g., finger/forearm oscillations or pendulum swinging). Very few studies, however, have explored the stable patterns of coordination that emerge during task-directed complementary coordination tasks. Thus, the aim of the current study was to investigate and model the behavioral dynamics of a complementary collision-avoidance task. Participant pairs performed a repetitive targeting task in which they moved computer stimuli back and forth between sets of target locations without colliding into each other. The results revealed that pairs quickly converged onto a stable, asymmetric pattern of movement coordination that reflected differential control across participants, with 1 participant adopting a more straight-line movement trajectory between targets, and the other participant adopting a more elliptical trajectory between targets. This asymmetric movement pattern was also characterized by a phase lag between participants and was essential to task success. Coupling directionality analysis and dynamical modeling revealed that this dynamic regime was due to participant-specific differences in the coupling functions that defined the task-dynamics of participant pairs. Collectively, the current findings provide evidence that the dynamical coordination processes previously identified to underlie simple motor synchronization can also support more complex, goal-directed, joint action behavior, and can participate the spontaneous emergence of complementary joint action roles.

Optimizing Digital Integrated Care via Micro‐Randomized Trials

Mobile health (mHealth) interventions are a promising tool in providing digitally mediated integrative care. They can extend care outside of the clinic by providing reminders to take medications, assisting in managing symptoms, and supporting healthy behaviors including physical activity, healthy eating, and stress management. mHealth interventions can adapt the delivery of care across time in order to optimize treatment effectiveness. Yet there exists limited empirical evidence useful to the development of adaptive mHealth interventions. This article describes a new randomized trial design, the Micro‐Randomized Trial (MRT), for informing the development of mHealth interventions. We provide examples of scientific questions important to the development of an mHealth intervention, and describe how these questions can be answered using an MRT.

Essential kinematic information, athletic experience, and affordance perception for others

The present study investigated the role of different types of movement in affordance perception, as well as the influence of sports experience. Perception of another actor’s maximum vertical jumping height and horizontal long-jumping distance was evaluated for basketball players, soccer players, and nonplayer controls after viewing point-light representations of the actors’ movements. Perceptual reports were more accurate after jumping-related movements (walking and squatting) were viewed than after nonrelated movements (standing and twisting). Vertical jump reports were more accurate than horizontal jump reports. Basketball and soccer players demonstrated higher accuracy than did controls. This research establishes that point-light displays contain essential kinematic information sufficient to support accurate affordance perception, and athletes appear better attuned to kinematic information specifying affordances for others as a result of their sports experience.

Quantifying and Modeling Coordination and Coherence in Pedestrian Groups

Coherent collective behavior emerges from local interactions between individuals that generate group dynamics. An outstanding question is how to quantify group coordination of non-rhythmic behavior, in order to understand the nature of these dynamics at both a local and global level. We investigate this problem in the context of a small group of four pedestrians walking to a goal, treating their speed, and heading as behavioral variables. To measure the local coordination between pairs of pedestrians, we employ cross-correlation to estimate coupling strength and cross-recurrence quantification (CRQ) analysis to estimate dynamic stability. When compared to reshuffled virtual control groups, the results indicate lower-dimensional behavior and a stronger, more stable coupling of walking speed in real groups. There were no differences in heading alignment observed between the real and virtual groups, due to the common goal. By modeling the local speed coupling, we can simulate coordination at the dyad and group levels. The findings demonstrate spontaneous coordination in pedestrian groups that gives rise to coherent global behavior. They also offer a methodological approach for investigating group dynamics in more complex settings.

Musical creativity and the embodied mind: Exploring the possibilities of 4E cognition and dynamical systems theory

The phenomenon of creativity has received a growing amount of attention from scholars working across a range of disciplines. While this research has produced many important insights, it has also traditionally tended to explore creativity in terms of the reception of products or outcomes, conceiving of it as a cognitive process that is limited to the individual domain of the creative agent. More recently, however, researchers have begun to develop perspectives on creativity that highlight the patterns of adaptive embodied interaction that occur between multiple agents, as well as the broader socio-material milieu they are situated in. This has promoted new understandings of creativity, which is now often considered as a distributed phenomenon. Because music involves such a wide range of socio-cultural, bodily, technological, and temporal dimensions it is increasingly taken as a paradigmatic example for researchers who wish to explore creativity from this more relational perspective. In this article, we aim to contribute to this project by discussing musical creativity in light of recent developments in embodied cognitive science. More specifically, we will attempt to frame an approach to musical creativity based in an 4E (embodied, embedded, enactive, and extended) understanding of cognition. We suggest that this approach may help us better understand creativity in terms of how interacting individuals and social groups bring forth worlds of meaning through shared, embodied processes of dynamic interactivity. We also explore how dynamical systems theory (DST) may offer useful tools for research and theory that align closely with the 4E perspective. To conclude, we summarize our discussion and suggest possibilities for future research.

Measuring regional displacements of tongue parts on ultrasound during /ɹ/ articulation

The ability to differentiate movements of the front, back and root portions of the tongue is important to the development of mature speech coordination. This ability is particularly relevant for sounds with complex tongue shapes, such as the American English rhotic approximant /ɹ/ (“r”), but speakers also have a wider scope of coarticulatory opportunities if able to control tongue parts independently [Zharkova, 2012]. In addition, lack of independence in tongue part movement is associated with speech sound disorders [Gibbon, 1999; Gick et al., 2008]. For this study, relative displacements of tongue blade, dorsum, and root were analyzed using MATLAB-based image processing. Regions of interest (ROIs) were drawn for these three areas on ultrasound images during production of /ɑɹ/ by 25 adults. Displacements of each region were measured by tracking of local brightness maxima from images representing /ɑ/ and /ɹ/ production, resulting in ranges of relative blade, dorsum and root displacement associated with nor...