Measuring Acoustic Social Worlds: Reflections on a Study of Multi-Agent Human Interaction

When individuals are sharing similar behavioral, physiological, or neural states—that is, when individuals’ actions, body states, or brain activity are changing together in time—then a collective interpersonal synergy forms (Riley et al., 2011). Each individual starts to behave together as a member of one large group. Measurement of an interpersonal synergy can be indicative of shared social cognition—of joint participation in co-regulating multiple patterns of activity between two or more agents engaged in a social interaction (De Jaegher, Di Paolo, Gallagher, 2010). In order to examine the dynamics of multiagent groups of people, and the emergence of these interpersonal synergies, scientists generally measure signals emitted by each individual to detect correlations between these signals.However, humans are highly capable of tracking complex behavioral dynamics of multiagent groups in our everyday interactions with the world even without access to individual behavioral, physiological, or neural signals from each individual agent. Our everyday human interactions provide us with access to a shared and co-created acoustic social world. Interactions among members of musical ensembles in particular provide useful insight into the co-creation of acoustic social worlds and the emergence of collective synergies. In the context of 4E cognition and the dynamical systems framework, this chapter provides an examination of the measurement of collective synergies from acoustic signals not of individual musicians, but of the acoustic signal co-created by a musical ensemble as a whole, in performance of a musical work that was composed to highlight the emergence of such a collective synergy.