1. Introduction: the concept of entrainment はじめに:エントレインメントの概念

The aim of this publication is to stimulate research in ethnomusicology rooted in the concept of entrainment, which describes the interaction and consequent synchronization of two or more rhythmic processes or oscillators. Entrainment as a concept has a considerable history – it was first identified by the Dutch physicist Christiaan Huygens in 1665 and has been applied widely in mathematics and in the physical, biological, and social sciences. It is a process that manifests itself in many ways, some of which involve human agency or cognition. Strangely though, it has had relatively little impact to date in studies of music, where it might be thought to be particularly relevant, and is only beginning to be seriously considered within ethnomusicology. This is, to our knowledge, the first publication to address the concept in detail from an ethnomusicological perspective.

In music research, we have seen an entrainment perspective adopted in the study of musical metre, particularly in the 1990s. Instead of looking for musical cues transmitted from performer to listener as the sole determinants of time and metre precepts, music psychologists have begun to apply an entrainment model in which rhythmic processes endogenous to the listener entrain to cues in the musical sound (Large and Kolen 1994). Although there is much to be done in this area, the entrainment model seems to reflect the cognitive processes much better than do previous models of metrical perception. Some recent work also points to new perspectives offered on the entrainment concept in the study of proto-musical behaviour in infants, and in the evolution of musical behaviour in the human species (Trevarthen, 1999-2000; Merker 2000).
音楽研究において、特に1990年代に入ってから、音楽拍子の研究にエントレインメントの視点が取り入れられるようになった。音楽心理学者は、演奏者から聴き手に伝わる音楽的な手がかりを時間や拍子の唯一の決定要因として探すのではなく、聴き手に内在するリズムのプロセスが音楽の音における手がかりに同調するという同調モデルを適用し始めている(Large and Kolen 1994)。この分野にはまだ多くの課題があるが、同調モデルはこれまでの計量的知覚のモデルよりも認知過程をよく反映していると思われる。また、最近の研究では、幼児の原始的な音楽行動の研究や、ヒトという種の音楽行動の進化において、エントレインメントという概念に新しい視点が提供されていることも指摘されている(Trevarthen, 1999-2000; Merker 2000)。

We believe that the concept of entrainment could have a particularly significant impact if applied to ethnomusicological research because it offers a new approach to understanding music making and music perception as an integrated, embodied and interactive process and can therefore shed light on many issues central to ethnomusicological thought. Entrainment may be central to an ethnomusicological orientation for which performance and listening are the focus of interest. Such a development is likely to be more productive if researchers share an understanding of what the concept implies (as well as what its limitations might be); we offer this contribution to colleagues in that spirit.

In later sections we discuss the relationship between entrainment and ethnomusicological research, and offer some suggestions regarding methods for investigation. Before that, however, it is important to establish what entrainment means and how other disciplines have characterised its main features. What follows is an overview of the concept of entrainment and its application in other fields, particularly the biological and social sciences (sections 2 and 3); some consideration of applications to date in music studies (section 4); some suggestions on the relevance of entrainment in ethnomusicology, with a preliminary consideration of possible methods (sections 5 and 6); and finally some case studies illustrating one methodological strand, that of chronometric analysis. Our focus is, of course, on music, but by discussing work in other fields we first aim to build up a more nuanced picture of entrainment and its ramifications so that ethnomusicological research can build more productively on this base.