Here's a review and synthesis of recent work and thinking on human synchrony (from the Dartmouth lab of Thalia Wheatley):
Thalia Wheatley, Olivia Kang, Carolyn Parkinson, and Christine E. Looser. From Mind Perception to Mental Connection: Synchrony as a Mechanism for Social Understanding. Social and Personality Psychology Compass 6/8 (2012): 589–606, 10.1111/j.1751-9004.2012.00450.xConnecting deeply with another mind is as enigmatic as it is fulfilling. Why people ‘‘click’’ with some people but not others is one of the great unsolved mysteries of science. However, research- ers from psychology and neuroscience are converging on a likely physiological basis for connec- tion – neural synchrony (entrainment). Here, we review research on the necessary precursors for interpersonal synchrony: the ability to detect a mind and resonate with its outputs. Further, We describe potential mechanisms for the development of synchrony between two minds. We then consider recent neuroimaging and behavioral evidence for the adaptive benefits of synchrony, including neural efficiency and the release of a reward signal that promotes future social interaction. In nature, neural synchrony yields behavioral synchrony. Humans use behavioral syn- chrony to promote neural synchrony, and thus, social bonding. This reverse-engineering of social connection is an important innovation likely underlying this distinctively human capacity to create large-scale social coordination and cohesion.
Three comments: 1) It's interesting to see this material framed in terms of The brain's Turing Tests. I take this as an index of how thoroughly the computational conception of mind has come to permeate our thinking. 2) I particularly recommend attention to the section, Neural efficiency: "A hallmark of mental connection is that it feels effortless." This has an affinity for the conception of pleasure I develop in Chapter 4 of Beethoven's Anvil. See also Bernstein's concept of dimensional compression which comes up in this post, Cooperation, Coupling, Music, and Soccer. 3) Attend to various remarks about loss of a sense of self.
Here's an article reporting a study of clapping (see my post The Sound of Many Hands Clapping: Group Intentionality):
Richard P. Mann1, Jolyon Faria, David J. T. Sumpter and Jens Krause. The dynamics of audience applause. Journal of the Royal Society Interface 6 August 2013 vol. 10 no. 85 20130466The study of social identity and crowd psychology looks at how and why individual people change their behaviour in response to others. Within a group, a new behaviour can emerge first in a few individuals before it spreads rapidly to all other members. A number of mathematical models have been hypothesized to describe these social contagion phenomena, but these models remain largely untested against empirical data. We used Bayesian model selection to test between various hypotheses about the spread of a simple social behaviour, applause after an academic presentation. Individuals' probability of starting clapping increased in proportion to the number of other audience members already ‘infected’ by this social contagion, regardless of their spatial proximity. The cessation of applause is similarly socially mediated, but is to a lesser degree controlled by the reluctance of individuals to clap too many times. We also found consistent differences between individuals in their willingness to start and stop clapping. The social contagion model arising from our analysis predicts that the time the audience spends clapping can vary considerably, even in the absence of any differences in the quality of the presentations they have heard.