Zhang, Mengsen

Relationships
Member of: Graduate College
Person Preferred Name
Zhang, Mengsen
Model
Digital Document
Publisher
Florida Atlantic University
Description
A fundamental question in Complexity Science is how numerous dynamic processes
coordinate with each other on multiple levels of description to form a complex
whole - a multiscale coordinative structure (e.g. a community of interacting people,
organs, cells, molecules etc.). This dissertation includes a series of empirical, theoretical
and methodological studies of rhythmic coordination between multiple agents
to uncover dynamic principles underlying multiscale coordinative structures. First,
a new experimental paradigm was developed for studying coordination at multiple
levels of description in intermediate-sized (N = 8) ensembles of humans. Based
on this paradigm, coordination dynamics in 15 ensembles was examined experimentally,
where the diversity of subjects movement frequency was manipulated to induce
di erent grouping behavior. Phase coordination between subjects was found to be
metastable with inphase and antiphase tendencies. Higher frequency diversity led
to segregation between frequency groups, reduced intragroup coordination, and dispersion
of dyadic phase relations (i.e. relations at di erent levels of description).
Subsequently, a model was developed, successfully capturing these observations. The
model reconciles the Kuramoto and the extended Haken-Kelso-Bunz model (for large- and small-scale coordination respectively) by adding the second-order coupling from
the latter to the former. The second order coupling is indispensable in capturing
experimental observations and connects behavioral complexity (i.e. multistability) of
coordinative structures across scales. Both the experimental and theoretical studies
revealed multiagent metastable coordination as a powerful mechanism for generating
complex spatiotemporal patterns. Coexistence of multiple phase relations gives rise
to many topologically distinct metastable patterns with di erent degrees of complexity.
Finally, a new data-analytic tool was developed to quantify complex metastable
patterns based on their topological features. The recurrence of topological features
revealed important structures and transitions in high-dimensional dynamic patterns
that eluded its non-topological counterparts. Taken together, the work has paved the
way for a deeper understanding of multiscale coordinative structures.
Model
Digital Document
Publisher
Florida Atlantic University
Description
Emotion and coordinated movement complimentarily depicts our social experiences.
How is motion colored? This study investigates variations in emotional responses during social
coordination. Subjects were instructed to coordinate their finger movement with a Virtual Partner
(VP), whose homologous movement was displayed as a video on the computer screen. The
partner was driven by the Haken-Kelso-Bunz equations, an empirically validated model that
captures behavioral and social coordination. It has been shown that people perceive VP as an
intentional human agent. In each of 80 trials, subjects coordinated for 8 sec inphase or antiphase
with VP, and then rated the partner’s intention (cooperation -VP intend same coordination
pattern as human-, or competition) and subjective response to a Turing test of partners’
humanness. VP cooperated for half of the time, and could change its intention in the middle of a
trial. Skin potential response (SPR) quantified the intensity of emotional responses. After
validating the SPR measurements, we compared emotional responses by coordination pattern,
cooperative~competitiveness, and humanness attribution. Subjects experienced higher emotional
responses when they believed that their partner was human. This was observed both during
coordination (ANOVA, p=0.020), and during rating (p=0.012). Furthermore during the rating
period, higher emotional responses were found for cooperative behavior (p=0.012), modulated
by VP’s change of intention and coordination pattern. This study suggests that emotional
responses are strongly influenced by features of the partner’s behavior associated with
humanness, cooperation and change of intention. Implications for mental health (e.g. autism) and
design of socially cooperative machines will be discussed.