Movements in social interactions are often unintentionally synchronized and dance-like. Recent research in social neuroscience has proposed that a special evolved "mirror" subsystem may be the neural substrate that facilitates these social interactions as well as their more mental concomitants such as rapport, empathy, and dominance relations. One wedge into understanding how the interpersonal coordination patterns emerge from the neural substrate comes from principles of dynamical entrainment. In order to establish the dynamical interpersonal synergy that is the basis for both intentional and spontaneous coordination, people must be attuned to the relevant information in the interpersonal situation. The proposed research explores the perceptual basis of interpersonal entrainment. Studies record the movements of people when they interact with each other in a common task. Movement records are analyzed using spectral and nonlinear time series methods to determine how the coordination patterns are affected by specific properties of the interaction. One such property is the perceptual pickup rhythm (e.g., as indexed by eye movements), which may play a role in interpersonal coordination patterns. Other experiments investigate how interpersonal coordination is affected by the biological/social nature of environmental stimuli, the relationship between mimicry phenomena and more tacit interpersonal coordination, and how behavioral interpersonal coordination is affected by psychological coordination (e.g., rapport) of the individuals involved. This research will provide a better understanding of the tacit dimension of movement coordination in human social interactions and will constrain our understanding of the role that the nervous system plays in creating social behavior. Understanding the bases of interactional synchrony is also important for understanding psychological dysfunction, in that such synchrony breaks down in pathologies such as schizophrenia, autism and even marital dissatisfaction.
Movement coordination is a fundamental aspect of everyday human activity and is essential for effective social interaction and joint action. Research in social neuroscience has proposed that special ‘mirror-neuron’ subsystems may be the material substrate that facilitates social interactions as well their more mental concomitants such as empathy. Over the last decade the PIs of this award have investigated the interpersonal perceiving and acting regularities that emerge from such neural substrates and form the basis for the ordered patterning of social movement coordination. This research has demonstrated that the processes of dynamical synchronization found generically in nature seems to lie beneath the patterning and stability of such coordination and, thus, provide a deep structure of support for the temporal coordination of joint action. Specifically, this research has demonstrated that a.) general dynamical processes of entrainment are involved in producing the spatio-temporal synchronization of interactors’ movements, b.) these dynamical processes cause the formation of an interpersonal dynamical coupled system, c.) these processes function outside of interactors’ awareness and over perceptual linkages, and d.) these processes operate regardless of whether the rhythmically moving stimulus is a social stimulus (i.e., body of another person) or a non-social stimulus (i.e., an animate environmental stimulus). A previous NSF award completed by the PIs investigated how informational linkages (visual vs. verbal) support interpersonal and social movement synergies of different kinds (limb vs. posture coordination) and found tentative evidence to suggest that the activity of perceptual pick-up (e.g., eye-movements) determines the strength of a synergy’s dynamics. The current award further explored the role of informational pick-up processes, and in particular, why eye tracking movements tend to strengthen unintentional interpersonal and social entrainment. Sixteen different studies were conducted in which a participant’s limb, body, and eye movements were recorded during laboratory tasks that required them to either interact with another person or with an animate stimulus display. Using nonlinear and spectral measures to evaluate the pattern and stability of the coordination that occurred under a variety of perceptual and motor manipulations the award resulted in the following findings: 1) perceptual pick-up processes determine the strength of unintentional social coordination and are indeed part of stable social movement coordination; 2) these perceptual pickup rhythms need to be overt and motorically-based rather than covert and attentional; 3) the occurrence and strength of social coordination can be facilitated by the biological nature of environmental stimuli and movements (e.g., motion that includes natural movement variability and/or has biologically plausible kinematics); 4) spontaneous and unintentional movement coordination can facilitate social interaction, increases rapport, and reduce perceived group differences; 5) there is an intimate relationship between cognitive processes and the gesturing that occurs in communicative interactions; 6) the increases in movement variability that occur when an individual observes the movements of a co-actor is not, as previously thought, a motor error or a motor interference effect, but rather is an emergent and constructive property of a social coordination goal; and 7) the patterns of human locomotion and movement can be understood as being the result of the lawful coupling relations that exist between the subcomponents of perceptual-motor systems. The research award provided in-depth research and training opportunities for over 20 undergraduate and graduate students across three institutions (Colby College, College of the Holy Cross, and the University of Cincinnati). The project adopted a multidisciplinary approach to experimentation that exposed these students to concepts from nonlinear dynamics (e.g., phase transitions, hysteresis) and a variety of advanced analysis techniques. Moreover, the collaborative nature of the project between two undergraduate colleges meant that the undergraduate students were exposed to an inter-collegiate research experience typically unavailable to them. More generally, the award resulted in the development of several new methods for objectively assessing visual coordination in a social or group setting, as well as the information pick-up processes involved in such coordination. Accordingly, others in the fields of perception and action, motor control, and social psychology have begun to examine the dynamics of the movement synchrony that occurs between interacting individuals, including what role interpersonal synchrony processes play in the social disconnection of children with autism. Finally, the award resulted in over 20 peer reviewed publications and book chapters, and over 35 conference presentations and posters (over 65% of which included undergraduate and graduate students as coauthors) for the two PIs.
