The Change Matters! Measuring the Effect of Changing the Leader in Joint Music Performances

In a joint action, a group of individuals coordinate their movements to reach a shared goal. When a change–i.e., an event that affects group functioning–occurs, the group adopts strategies to face it. This article investigates how a change involving a strategic core role in a group affects interpersonal coordination, and ultimately group effectiveness in performing a joint action. Following the entrainment theory, interpersonal coordination is addressed in terms of the rhythmic cycles of the individuals and of the group and their adjustment. Music is used as an ideal ecological scenario for investigation. More specifically, this article focuses on orchestra playing. By adopting a computational approach, research is devoted to measure how a change of conductor (i.e., the leader) influences entrainment between players and its variation over time as well as the relationship between entrainment and external ratings of the orchestra performance. Results show that, whereas the change of conductor had a limited significant effect on entrainment, a significant effect was found when entrainment is used as a predictor of the external ratings. Both the obtained results and the techniques developed for measuring entrainment may open novel research directions in the area of automated analysis of group behavior, and particularly of emotion in groups.