Instructed timing and body posture in guitar and bass playing in groove performance

Body movements play a crucial role in music performance and perception, and they do so well beyond those devoted to sound production itself. Various movements related to the performer’s emotional intentions or structural aspects of the music are also part of the performance and crucial to the listening experience. In the present study, we investigated the effect of instructed timing on such non-sound producing body movements, focusing on musicians’ body posture. We used an infrared motion-capture system to record the movements of skilled guitarists and bassists while they were playing electric guitar and electric bass, respectively. We instructed the musicians to perform under three different timing-style conditions: laid-back (behind), on-the-beat, and pushed (ahead). We also conducted short semistructured interviews to gain further insight into their movement strategies. The results show that performers generally leaned forward when instructed to play systematically slightly ahead of the pulse. We suggest that this change is related to an alteration in the performer’s experience of the feel of the music. The results support the view that musicians’ non-sound-producing body movements are not random, but integral to the performance, and that they are closely related to the music’s microrhythmic feel.