The role of Temporal Context in the Tritone Paradox

The Tritone Paradox refers to a sequence of two specially synthesised "Shepard" tones which may sound ascending to one listener, and descending to another. The present study examines a recent suggestion that people's responses on this task may be determined by neural processes which are sensitive to temporal variations in pitch - so-called spectral motion detectors. Twelve listeners with normal hearing were presented with pairs of Shepard tones in each of two conditions - first in the traditional sequential manner, and then simultaneously, with one tone presented to each ear. Results indicated that respondents were able to judge consistent relationships between the tones even when presented simultaneously, and a high degree of similarity was observed between responses in each condition. The implications of these results for current theories of the Tritone Paradox are discussed.