How secure memorization promotes expression: A longitudinal case study of performing Chopin’s Barcarolle, Op. 60

Experienced musicians can perform reliably from memory because they prepare performance cues (PCs) that allow them to recover when performance is disrupted. We describe a longitudinal case study in which a pianist (the second author) learned and performed Chopin’s Barcarolle, Op. 60, over a 12-year period. The pianist provided PC reports for 28 performances, starting a month before her first public performance. Shortly after each performance, she marked the features of the music that guided her playing (PCs) on a clean copy of the score, distinguishing five types of PC: structural, Schenkerian (tonal elaborations), expressive, interpretive, and basic. Structural PCs predominated at first and were later replaced by expressive and Schenkerian PCs. PCs were more frequent at structural boundaries than at other locations. This boundary effect was larger under typical, compared to atypical performance conditions, and increased over time, suggesting that the main function of PCs was promoting expression rather than guarding against mistakes. Although the pianist’s initial purpose in learning to use PCs was to have a safety net in case of memory failure, she was surprised to find that she enjoyed playing with PCs and believed they helped her to play more expressively.