Correspondence in Perception of the Tritone Paradox and Perfect-Fifth/Perfect-Fourth Intervals

Shepard (1964) found that the pitch height of a pair of octave-related complex tones is perceived in accordance with the principle of proximity around a pitch class circle. However, when these tones form a tritone interval, proximity cannot be used. In the tritone paradox, Deutsch (1986) found that listeners perceive these tones such that half of the pitch class circle is heard as higher in pitch, and the opposite half as lower, with individual differences in which half is heard as higher. In the present experiments, listeners judged the height of octave-related complexes forming tritones and forming intervals of perfect fifths (P5) and perfect fourths (P4). There was a strong relationship between the pitch classes heard higher in the tritone paradox and those heard higher when presented with P5/P4 intervals. Rather than using proximity to judge pitch height with P5/P4 intervals, listeners instead use the same mechanism involved in perception of the tritone paradox.