PERFORMANCES BY CONCERT PIANISTS in the Western classical tradition are normally highly prepared, yet must sound fresh and spontaneous. We propose that musicians achieve the necessary spontaneity by strategic management of the variability inherent in any action. Musical gestures that make up the artist's interpretation (e.g., crescendos, ritardandos) are attenuated or exaggerated to different degrees in each performance, while movements critical for technique are less varied.We examined 7 highly polished performances of J.S. Bach's Italian Concerto (Presto) by a concert pianist. There were small but consistent differences between performances in 4 of 9 identified musical gestures, each of which occurred in several locations. In contrast, at points where the pianist reported attending to technique during performance, slower tempi and lower dynamic variability suggested that she controlled execution of planned movements more closely. Increased control at technical difficulties permitted more spontaneous variation in the musical gestures important to her interpretation.
Experts in many fields approach a new problem by identifying the general principles involved before starting work on details. Do expert musicians similarly begin work on a new piece with the big picture, an artistic image of the piece, in mind? To find out, a concert pianist recorded her practice of the third movement, Presto , of J. S. Bach's Italian Concerto , commenting as she did so about what she was doing. The behavioral record of where playing started, stopped, and slowed down indicated the musical dimensions affecting practice, while the comments indicated the main focus of the pianist's attention. An artistic image for the piece was already evident in the initial sight-read performance, guided work on technique in sessions 1-6, and was transformed into a plan for performance by practice of performance cues in sessions 7-8. Interpretive details were added in sessions 9-10 and remaining problems touched up in session 11-12. Despite its pervasive effects on practice, the pianist's artistic image was mentioned only indirectly in comments about technique in sessions 1-6 and about structure, memory, and interpretation in later sessions.