Over the last decade, the concept of entrainment—emerging from the fields of physics and biology—has grown as a tool for investigating rhythmic adjustments among musicians, and between different groups of musicians. When combined with methods of audio data analysis, this approach has benefits for the assessment of musical behavior, previously limited to largely descriptive ethnomusicological research based on ethnographic data collected through field study. However, musical behavior is not only biophysically determined, but also a highly social activity. Therefore, this article focuses on “social entrainment”—a concept coined by the social scientists Joseph E. McGrath and Janice R. Kelly in 1986 which recently has been taken up in music research. Relating this concept to certain approaches in relevant current empirical studies on interpersonal coordination, the authors develop their own categories of social behavior, which are broader than those of social entrainment but can accordingly be applied to the social entrainment that may occur in musical practices. These categories range from basic behaviors that do not involve social cognition but are meaningful to interacting individuals and groups, to high-order social behaviors that require collective intentionality and can lead to sophisticated interaction involving music-specific phenomena such as a “groove.” Consequently, a concept of entrainment which goes beyond both an adaptation of the established concept of physical and biological entrainment and McGrath and Kelly’s original concept of social entrainment is proposed: “musical social entrainment.” The authors use this term to refer to intra-individual, inter-individual, intra-group, and inter-group entrainment to exogenous musical rhythms—including the rhythms of other musically acting individuals and groups—embedded in a social context and contributing to sociality. Finally, reviewing selected studies relevant to musical social entrainment, the authors discuss problems and open questions concerning music-related entrainment research, and potential contributions in the future of entrainment studies in general.

The purpose of the study was to investigate the effectiveness of musical feedback on the stride length of patients with idiopathic Parkinson's disease (PD). To do that, we extended the concept of rhythmic auditory stimulation (RAS) with interactive musical feedback (MF). The comparison between RAS, MF, and no stimulation was conducted on a sample of 15 PD patients in a randomized repeated-measures design. All 3 interventions included verbal instructions to make long steps. As a countercheck, a further investigation with the same design was conducted on 10 healthy participants matched for age, sex, and height. In the MF condition, as the stride length increased, the complexity of the music increased over 5 different levels, ranging from a simple beat to a full orchestral sound. We hypothesized that MF, operating on a fast, nearly automatic level, fosters a greater stride length than the other conditions. Both PD and healthy participants confirmed our hypothesis in the within-subjects comparison. For patients, MF was significantly more effective than the other conditions; for healthy participants, MF did not show significance, but had nonetheless a small effect size. Our results encourage further research on the role of musical feedback as a therapeutic device.

Sentire is a body–machine interface that sonifies motor behaviour in real time and a participatory, interactive performance in which two people use their physical movements to collaboratively create sound while constantly being influenced by the results. Based on our informal observation that basal social behaviours emerge during Sentire performances, the present article investigates our principal hypothesis that Sentire can foster basic mechanisms underlying non-verbal social interaction. We illustrate how coordination serves as a crucial basic mechanism for social interaction, and consider how it is addressed by various therapeutic approaches, including therapeutic use of real-time auditory feedback. Then we argue that the implementation of Sentire may be fruitful in healthcare contexts and in promoting general well-being. We describe how the Sentire system has been developed further within the scope of the research project ‘Social interaction through sound feedback–Sentire’ that combines human–computer interaction, sound design and real-world research, against the background of the relationship between sound, sociality and therapy. The question concerning how interaction is facilitated through Sentire is addressed through the first results of behavioural analysis using structured observation, which allows for a quasi-quantitative sequential analysis of interactive behaviour.

Sentire is both an artwork and a research project in which proximity and touch are sonified with the aim to enhance body perception and social interaction. Sentire uses a digital system that mediates body movements and musical sounds, using a Body-Machine-Interface that allows two (or more) people to interact with one an- other in a physical environment—rather than in a virtual environment. The artwork consists of a participatory performance, which has been presented at numerous events since 2016. Distance and touch between the users can be measured and mapped to an algorithmic sound environment in real time. Through this multi- modal experience, the awareness of the self and the other is enhanced on bodily, especially kinaesthetic levels, i.e. movement perception. Since 2019, Sentire has been also a research project at the Humboldt University of Berlin , with the aim to develop the system for therapeutic purposes.