Wenyi Huang
Michael D. Hall
Richard E. Pastore
Psychoacoust. Lab., Ctr. for Cognitive and Psycholinguist. Sci., SUNY, Binghamton, NY 13902-6000
In the octave illusion, dichotic pairs of octave-related tones are physically alternated across ears, with perception of only a single fused tone shifting both in pitch and from side-to-side in synchrony with the physical alternation. Huang et al. [J. Acoust. Soc. Am. 91, 2374 (A) (1992)] demonstrated that dichotic fusion of octave stimuli is a primary factor in the occurrence of the illusion. Since the work of Helmholtz, it has been known that fusion occurs most often for stimuli in an octave relationship and decreases in frequency for other specified relationships. Therefore it is conjectured that similar illusion patterns should be observed with specific frequency intervals other than octaves. Experiment 1 evaluated the incidence of dichotic fusion for different frequency integer ratio. Experiment 2 replicated parts of experiment 1 and determined the incidence of the illusion for some noninteger frequency ratios. Incidence of the illusion tended to be greater for stimuli that are known to more readily fuse. [Research supported by NSF and AFOSR.]