Musician subjects were required to detect interval and contour changes in transposed versions of standard melodies of 3, 5, 7, 9,11,13, and 15 notes. Subjects were significantly better at detecting contour alterations for melodies of up to 11 notes but significantly better at detecting interval alterations in the 15-note melodies. Serial position effects for 5-, 7-, and 9-note melodies showed contour to be immediately precise after transposition, whereas the ability to detect interval alterations improved as the melodies progressed. These results suggest that, on transposition, contour information is immediately precise but is lost as melody length increases. Interval information is initially less precise but is more resistant to forgetting in longer melodies. The implication of this is that contour can be encoded independently of tonal context, whereas interval information becomes more precise as a tonal framework is established. Some musical implications of the finding are discussed.