Pleasantness makes a good time: musical consonance shapes interpersonal synchronization in dyadic joint action

Abstract

Introduction: Music making is a process by which humans across cultures come together to create patterns of sounds that are aesthetically pleasing. What remains unclear is how this aesthetic outcome affects the sensorimotor interaction between participants.

Method: Here we approach this question using an interpersonal sensorimotor synchronization paradigm to test whether the quality of a jointly created chord (consonant vs. dissonant) affects movement coordination. We recruited non-musician participants in dyads to perform a dyadic synchronization-continuation task (dSCT): on each trial, participants first synchronized their movements to a metronome (synchronization phase) and then continued tapping together at the same tempo without the metronome (continuation phase). Each tap yielded a note and participants heard both their own and that of their partner, thus creating a chord that was varied to be either consonant (Perf5 or Maj6) or dissonant (Min2 or Maj2). For each trial, participants also rated the pleasure they felt in creating the sounds together. Additionally, they completed questionnaires about social closeness to the other participant, musical reward sensitivity and musical training.

Results: Results showed that participants' taps were closer in time when they jointly created consonant (high pleasure) vs. dissonant (low pleasure) chords, and that pleasure experienced by the dyad in each trial predicted interpersonal synchronization. However, consonance did not affect individual synchronization with the metronome or individual tapping when the metronome was discontinued. The effect of consonance on synchronization was greater in dyads who reported feeling less close prior to the task.

Discussion: Together, these results highlight the role of consonance in shaping the temporal coordination of our actions with others. More broadly, this work shows that the aesthetic outcome of what we create together affects joint behaviors.

Keywords: consonance; interpersonal synchronization; joint action; joint outcome; musical pleasantness.

Figure 1

(A) Flow chart of the procedure. IOS, Inclusion of Other in Self scale, administered once before (pre) and once after (post) the dSCT; Individual-SCT, individual synchronization-continuation task; dSCT, dyadic synchronization-continuation task; eBMRQ, extended Barcelona Music Reward Questionnaire; Gold-MSI, Goldsmith Musical Sophistication Index; AQ, Autism Quotient Questionnaire. Assessment of inter-individual differences is outlined in gray, while the assessment of pitch discrimination and synchronization abilities with a dashed line. (B) Top view of the experimental setup. Participants sat facing each other on opposite sides of the table, with a central panel preventing them from seeing each other; they wore noise-canceling earphones. Participant A of the dyad (in blue) taps on the “A” key of one keyboard, while participant B (in yellow) on the “L” key of the other. Keyboards and earphones were linked to the same computer. (C) The four musical chords employed in the experiment, divided into consonant and dissonant ones. (D) Dyadic synchronization-continuation task (dSCT) structure. Red dots indicate clicks of the metronome, which is discontinued in the continuation phase, while blue (Participant A) and yellow (Participant B) dots refer to participants' taps. A gong (depicted on top right corner) indicates the end of each trial. Time differences between each participant's tap and the closest metronome click (Δt = tap A/B – metronome) were calculated for the individual timing in the synchronization phase, while time differences between participant A and B closest taps were computed for the interpersonal synchronization (Δt = |tap A – tap B|) in both synchronization and continuation phase, bottom right corner of the Figure.

Figure 2

Subjective rating of pleasure. Boxplot of the subjective ratings of pleasure as a function of auditory feedback duration (150, 200, and 400 ms), consonance (consonant vs. dissonant) and split by metronome IOI (450, 550, and 650 ms). Diamonds indicate the mean for each condition, while dots refer to the single participants' mean pleasure rating for that specific combination of conditions. Asterisks indicate a significant difference between consonant vs. dissonant in that specific combination of conditions.

Figure 3

Pleasure and interpersonal synchronization relationship for all dyads. (A) Shows one example dyad. Each dot corresponds to one of the 72 trials. The red line indicates the regression model fit, predicting the mean of absolute taps difference (in log ms, not averaged per trial) by dyadic average ratings of pleasure (slope = 0.15), and the shaded area its standard error. Note that the y axis is inverted with higher values suggesting better interpersonal synchrony. The slope was extracted for group analysis. This analysis was repeated for all dyads individually. (B) Shows the slopes for all the dyads as dots. The red dot indicates the slope for the dyad shown in (A); the diamond indicates the slopes' mean. Higher values indicate steeper slope lines.

Figure 4

Consonance effect. (A) Boxplot of the subjective ratings of pleasure as a function of consonance (consonant vs. dissonant). Dots refer to the individual participants' mean rating of pleasure for each condition. (B) Boxplot of consonance effect on interpersonal synchronization (measured as the mean of absolute taps difference log transformed). Diamonds indicate the general consonant and dissonant means, while dots refer to the dyadic mean of absolute taps difference for each condition. Note that the y axis is inverted so that higher values suggest better interpersonal synchrony. (C) Boxplot of the consonance effect on the individual tapping precision (tap timing relative to the metronome) in the synchronization phase (measured as the mean of signed time differences in ms). Diamonds indicate the general consonant and dissonant means, while dots refer to the individual mean of signed difference for each condition. Zero suggests perfect synchronization with the metronome. (D) Boxplot of the consonance effect on individual tapping precision in the continuation phase (measured as mean inter-tap interval, mean ITI). Diamonds indicate consonant and dissonant mean ITI, while dots refer to the individual mean ITI for each condition. Asterisks indicate a significant difference between consonant vs. dissonant condition.

Figure 5

Correlation with consonance effect (A, B) and interpersonal synchronization (C, D). (A, B) Depict the consonance effect (measured as interpersonal synchronization in the consonant minus the dissonant trials, in log ms) by dyadic sum of (A) music reward sensitivity (eBMRQ) and (B) social closeness before the experimental session (IOS pre, expressed in percentage). Higher points suggest higher consonant effect. Dashed lines indicate values with no consonance-dissonance difference. (C, D) Represent the interpersonal synchronization (measured as the mean of absolute taps difference in log ms) as a function of the dyadic sum of (C) musical training and (D) perceptual abilities. Each point indicates the mean of absolute taps difference for each dyad. Note that the y axis is inverted with higher values suggesting better interpersonal synchrony. Lines indicate the regression model fit and the shaded area its standard error. Asterisks indicate significant correlations.