DIBRIS, University of Genoa, Genoa, Italy.
MARCS Institute for Brain, Behaviour and Development, Western Sydney University, Penrith, Australia.
PLoS One. 2024 Apr 3;19(4):e0300663. doi: 10.1371/journal.pone.0300663. eCollection 2024.
Music ensemble performance provides an ecologically valid context for investigating leadership dynamics in small group interactions. Musical texture, specifically the relative salience of simultaneously sounding ensemble parts, is a feature that can potentially alter leadership dynamics by introducing hierarchical relationships between individual parts. The present study extended previous work on quantifying interpersonal coupling in musical ensembles by examining the relationship between musical texture and leader-follower relations, operationalised as directionality of influence between co-performers' body motion in concert video recordings. It was hypothesised that the directionality of influence, indexed by Granger Causality, would be greater for 'homophonic' textures with a clear distinction between melody and accompaniment parts than for 'polyphonic' textures with less distinction between melody and accompaniment. This hypothesis was tested by using pose estimation algorithms to track instrumentalists' body movements in a string quartet and a clarinet quintet, and then applying Granger Causality analysis to their head motion to estimate directional influence between instrumentalist pairs for sections of the pieces that varied in texture. It was found that Granger Causality values were generally higher (indicating greater directionality of influence) for homophonic than polyphonic textures. Furthermore, considering melody and accompaniment instrument roles revealed more evidence for the melody instrument influencing accompanying instruments than vice versa, plus a high degree of directionality among accompanying instruments, in homophonic textures. These observed patterns of directional information flow in co-performer body motion are consistent with changing leader-follower relations depending on hierarchical relations between ensemble parts in terms of the relative salience of melodic material in the musical texture. The finding that automatic pose estimation can detect modulations of leadership dynamics in standard video recordings under naturalistic performance conditions has implications for investigating interpersonal coordination in large-scale music video datasets representing different cultural traditions, and for exploring nonverbal communication in group activities more generally.
音乐合奏表演为研究小团体互动中的领导动态提供了一个生态有效的环境。音乐织体，特别是同时发声的合奏部分的相对突出性，是一种可能通过在个体部分之间引入层次关系来改变领导动态的特征。本研究通过检查音乐织体与领导者-追随者关系之间的关系，扩展了以前关于量化音乐合奏中人际耦合的工作，这种关系表现为在音乐会视频记录中表演者身体运动之间的影响方向。假设影响的方向，即由格兰杰因果关系索引，对于具有明显旋律和伴奏部分之间区别的“主调”织体，将大于具有旋律和伴奏部分之间区别较小的“复调”织体。通过使用姿势估计算法跟踪弦乐四重奏和单簧管五重奏中乐器演奏者的身体运动，然后将格兰杰因果关系分析应用于他们的头部运动，以估计不同织体部分中乐器演奏者对的头部运动的定向影响，来检验这一假设。结果发现，对于主调织体，格兰杰因果关系值通常高于复调织体（表示影响的方向更大）。此外，考虑旋律和伴奏乐器角色，除了在主调织体中伴奏乐器之间存在高度的定向性之外，还发现旋律乐器对伴奏乐器的影响大于反之。在合奏部分的相对突出性方面，在旋律材料方面，这些观察到的协同表演者身体运动中定向信息流模式与领导动态的变化一致。在自然表演条件下，自动姿势估计可以检测标准视频记录中领导动态的调制，这对于研究代表不同文化传统的大型音乐视频数据集的人际协调以及更广泛地探索群体活动中的非言语交流具有重要意义。
