Here’s an experiment to try the next time you’re on the phone with a colleague or friend: As you’re listening to the other person talk, see if you can guess whether they’re also gesticulating with their hands and how.
There’s a strong chance that your conversation partner’s movements will leave an acoustic signature that you may be able to perceive, says Wim Pouw, a cognitive scientist at the Donders Institute for Brain, Cognition and Behaviour at Radboud University Nijmegen in the Netherlands and the author of a new study on this topic recently published in the journal PNAS.
In previous research, Pouw discovered that upper limb and wrist movements created acoustic imprints on vocalizations. Now, working with a team of researchers at the University of Connecticut, he found people who listened to an audio recording of someone saying “ahh” while making a hand gesture as if they were chopping wood (but also keeping their “ahh” as steady as possible) could accurately replicate the speaker’s chopping gestures, at the right tempo, without any visual references. The synchronicity was spontaneous and flawless.