Tritone Paradox

Discovered by Diana Deutsch (UCSD) in 1986.

Click to Listen

• Example consists of four two-tone patterns.
• Decide whether it is going up or down in pitch.
• When listening in groups, some people hear a pattern as ascending, others descending.

Two computer-produced tones, a tritone apart, are played in sequence: for some, that pattern has the illusion of ascending, while for others, it's decending.

Generally, when a melody is transposed, the perceived relationship between tones is unchanged.

• In the Tritone Paradox, when one pair of notes is played (C followed by F#), a listener might hear a descending pattern.

• Yet when a different pair is played (G# followed by D) the same listener hears an ascending pattern.