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 th e tritone task, presenting them with a continuous ascending or descend ing chromatic scale created using Shepard tones, and then retesting th em on the tritone task. Results indicated a negative-motion aftereffec t that affected the orientation of the pitch class circle. Differentia l 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 Th e implications of this dissociation are discussed. In addition, since our subjects lived relatively close to the U.S. border, the experiment al pretests allowed us to examine the hypothesis that a canonical Amer ican pitch template similar to that found among ''Californian'' subjec ts (Deutsch, 1991) is propagated by linguistic influences of media suc h as television and radio (Ragozzine & Deutsch, 1994). A sun ey of our subjects indicated that overall, the majority of time engaged in list ening to the radio and watching television or movies was spent with Am erican sources. Despite this, and despite the fact that subjects had w idely varying language and cultural backgrounds, a tight distribution of peak-pitch classes was found that is indicative of a ''British'' pi tch template (Deutsch, 1991) for every subject tested.