The difficulty of discerning between composed and improvised music

Abstract

The generative processes (types) of composition and improvisation are often claimed to differ from each other with respect to complexity, spontaneity, and listener expectation. While this conceptual difference might be tenable, it is unclear whether it has an empirical perceptual basis. In a listening experiment with three contrasting pieces - classical (Mozart), romantic (Scriabin), and free jazz (Rissi) - we compared composed and non-composed musical stimuli. 102 experts rated six one-minute excerpts using the scales “spontaneous/improvised” and “coherent/ rehearsed”. The ratings were of acceptable, though moderate, reliability, and the listeners reacted markedly differently to the three styles. However, the effect of generative type was either non-significant (Mozart, Scriabin) or caused by performative aspects for the free jazz piece (Rissi). This lack of clear evidence for perceiving the two generative types is in line with other research showing divergence between theoretical concepts and their perceptual salience.