Improvisation is the nascency of spontaneous music. Improvisation is often considered an achievement of instantaneous composition by composers, where compositional techniques are employed with or without preparation.
This is relevant because it indicates that music is a deeper cognitive process than unexamined phrases such as, "pleasing to the ear" would suggest. Much research in harmony cognition seeks to uncover these conglomerate mental processes involved in Personalized Music listening to music, which may seem intuitively simple, yet are vastly intricate and complex.