An auditory paradox

This paper describes and demonstrates a pattern of tones with some remarkable properties. When played in one key, it is heard as ascending; yet, when played in a different key, it is heard as descending instead. When a tape recording is made of the pattern and it is played back at different speeds, the pattern is heard either as ascending or as descending, depending on the speed of playback. To add to the paradox, when the pattern is played in any one key it is heard as ascending by some listeners but as descending by others. This effect is shown to be robust in the face of a number of parametric manipulations. Implications for processes underlying pitch perception are discussed.