Spectral-motion aftereffects and the tritone paradox among Canadian subjects.

The effect of spectral motion on the tritone paradox was investigated by pretesting subjects residing in southwestern Ontario, Canada, on the tritone task, presenting them with a continuous ascending or descending chromatic scale created using Shepard tones, and then retesting them on the tritone task. Results indicated a negative-motion aftereffect that affected the orientation of the pitch class circle. Differential effects of perceived pitch height on the lower portion of the pitch class circle and of adaptation on the upper portion of the pitch class circle were found in the pre- and postadaptation data, respectively. The implications of this dissociation are discussed. In addition, since our subjects lived relatively close to the U.S. border, the experimental pretests allowed us to examine the hypothesis that a canonical American pitch template similar to that found among "Californian" subjects (Deutsch, 1991) is propagated by linguistic influences of media such as television and radio (Ragozzine & Deutsch, 1994). A survey of our subjects indicated that overall, the majority of time engaged in listening to the radio and watching television or movies was spent with American sources. Despite this, and despite the fact that subjects had widely varying language and cultural backgrounds, a tight distribution of peak-pitch classes was found that is indicative of a "British" pitch template (Deutsch, 1991) for every subject tested.