When dance partners perform, their bodily movements become synchronised. This is deliberate on their part, of course, and we can see the timed interplay of their actions. What psychologists have begun to realise is that this kind of bodily synchrony also occurs between people in many everyday situations, except in these cases the physical “dance” is unintentional and it’s more subtle, such as when two people sitting in rocking chairs begin to rock in time without realising it.
For the latest demonstration of this effect, Richard Schmidt and his colleagues have explored the physical choreography that occurs between people during the telling of formulaic knock-knock jokes. The researchers used a Kinect camera to record the movements of 32 students as they performed these jokes in pairs. The Kinect, which is found in many homes as part of a video-gaming console, detects the 3D locations of 21 body joints for each person, and records up to 30 frames per second. Eight of the participant pairs had never met each other before, but before the joke telling all pairs performed physical ice-breaker exercises, such as standing back-to-back, locking arms and attempting to stand up together. There were eight all-female pairs, and eight mixed-gender pairs.
The researchers observed significant bodily movement synchrony between joke tellers and responders. This was true across a session of ten jokes; within each joke lasting five to seven seconds; and also within each joke sub-component, such as each utterance or teller-responder exchange. This synchrony was not due to chance – when the researchers compared movement between participants who were not paired together, no such synchrony was observed. In technical terms, the synchrony between joke tellers and responders was “in-phase” – that is, bodily movement by the teller was reliably followed by movement by the responder; and it also showed “coherence”, in that the lag between teller and responder tended not to change over time.
Schmidt and his colleagues said their study has shown the “bodily ‘dance’ underlying human communication interactions…” There were some further details to the study. Half the time, the pairs performed the jokes facing away from each other. This reduced, but did not eliminate, the “dance”. Half the pairs were told to perform certain gestures during the joke telling – for example, the teller was to perform a door knocking mime, and the responder to shrug their shoulders when they uttered “Who’s there?”. The dance between teller and responder was actually reduced for these pairs. The researchers surmised that this is because focusing on performing these prescribed movements took the participants’ attention away from their partner.
Finally, after the main task, the participants completed questionnaires tapping their social skills – a measure of social monitoring (how much a person tailors their behaviour to the social context) and the Autism Spectrum Quotient. People who scored higher on the latter measure tended to display less of a “dance” during the joke telling/responding. Zooming in on the sub-scales of this autism measure, social skills were not relevant. Rather, it was specifically those people who said they paid more attention to detail and/or had trouble switching their attention, who also tended to display less of a physical “dance” with their partner during the joke telling.
“Individuals vary in terms of their ability to create stable interpersonal entrainment,” the researchers said, “and such skill seems to be underwritten by the flexibility by which they can attend to and pick up information about their environment.”