It Takes Two: Interpersonal Neural Synchrony Is Increased after Musical Interaction

Abstract

Music's deeply interpersonal nature suggests that music-derived neuroplasticity relates to interpersonal temporal dynamics, or synchrony. Interpersonal neural synchrony (INS) has been found to correlate with increased behavioral synchrony during social interactions and may represent mechanisms that support them. As social interactions often do not have clearly delineated boundaries, and many start and stop intermittently, we hypothesize that a neural signature of INS may be detectable following an interaction. The present study aimed to investigate this hypothesis using a pre-post paradigm, measuring interbrain phase coherence before and after a cooperative dyadic musical interaction. Ten dyads underwent synchronous electroencephalographic (EEG) recording during silent, non-interactive periods before and after a musical interaction in the form of a cooperative tapping game. Significant post-interaction increases in delta band INS were found in the post-condition and were positively correlated with the duration of the preceding interaction. These findings suggest a mechanism by which social interaction may be efficiently continued after interruption and hold the potential for measuring neuroplastic adaption in longitudinal studies. These findings also support the idea that INS during social interaction represents active mechanisms for maintaining synchrony rather than mere parallel processing of stimuli and motor activity.

Keywords: electroencephalography (EEG); entrainment; hyperscanning; interbrain phase coherence; interpersonal neural synchrony; interpersonal synchrony; music; neuroplasticity.

Figure 1

An illustration of the experimental setup during the tapping game. Participants wearing EEG caps (A,B) faced each other during the tapping game, tapping on a synth drum pad (1), and turned 90 degrees to their left during pre/post silent periods. Guide tones were played through a speaker (2) from a computer (C) in an adjacent room, which was also used for data collection.

Figure 2

Left: Cognionics headset used for the present study (viewed from the left); right top: a research assistant tests the headset and drum machine; right bottom: tined and smooth electrodes for placement in hair and on the skin, respectively.

Figure 3

(Top) Representation of one instance of the anti-phase tapping game. The sequence above was repeated multiple times at increasing rates (tempi) selected by participants. (Bottom) Representation of the entire study procedure each dyad underwent.

Figure 4

Grand average wavelet power at each of the 5 electrode sites. PRE (black) POST (red). Shading shows standard error and horizontal bars show delta and theta band analysis regions.

Figure 5

(A) Bar graphs representing mean phase correlation in PRE (grey) and POST (red) conditions at each of the five electrode sites used for the study. Statistical significance is indicated by the asterisks (*). (B) Correlations between duration of musical interaction and POST condition delta band INS.

Figure 6

Relative phase per trial for participant dyads. Each dyad’s trials comprise blue dots connected by a blue line. The final trial of each dyad is marked in bold.