When a musician is playing a piece, and the audience is enjoying it, they can develop physical synchronies. Both might tap their feet, sway their bodies, or clap their hands.
“Through music, the producer and the perceiver connect emotionally and behaviourally,” note the authors of a new paper, published in NeuroImage. And now this team, led by Yingying Hou at East China Normal University, has uncovered a connection right down at the neural level. The team has observed “inter-brain coherence” (IBC) — a synchronisation in brain activity — between a musician and the audience. What’s more, the strength of this coherence could be used to predict how much the audience enjoyed a piece.
The team used a technique called near-infrared spectroscopy to monitor the brain activity of a professional violinist while he was videoed playing a series of 12 brief, classical pieces. They then used the same technique (which involves shining beams of light through the skull, to monitor changes in blood flow) on 16 women while they watched the video, and listened to all of these pieces. (Because gender differences in inter-brain synchronisation have previously been observed, only women were recruited as listeners.)
The violinist had been instructed to look directly at the camera and maintain a neutral expression while he played the pieces, which each lasted about 100 seconds. If he was enjoying one piece more than another, the team hoped this would not be obvious to the viewers. They were told to gaze at the violinist’s face while they listened. After each piece, they rated how much they liked it on a seven-point scale.
The data revealed inter-brain coherence between each of the listeners and the musician, for all of the violin pieces. That is, there were similar patterns of heightened activity in certain key regions of the brain while the violinist played and the other participants listened.