A comparison of the vowel sequence illusion and the verbal transformation effect
Jeffrey M. Cooley, Richard M. Warren, James A. Bashford · The Journal of the Acoustical Society of America · 2000
When repeated sequences of steady-state vowels have durations of their phonetic components below the 100-ms threshold for identification of order, the phonemes lose their identity. The sequences are heard as syllables occurring in the listener’s lexicon (the Vowel-Sequence Illusion). When listening to repeating words, listeners also hear illusory syllables occurring in their lexicon (the Verbal-Transformation Illusion). Verbal transformations require the decay (satiation) of the initial veridical organization before the repetition-induced shifts in criteria permit nonveridical forms to be heard: The Vowel-Sequence Illusion does not require initial verbal satiation, and hence permits repetition-induced criteria shifts to tap directly into the lexicon-based syllabary. The intrinsic differences in the nature of the phonetic stimuli producing the two illusions result in characteristic distinctions between the organizations heard in the two illusions. Among these distinctions is the spectral splitting of the vowel sequences into two simultaneous organizations, one consisting of components above and the other below the 1500-Hz crossover frequency encountered in other contexts. This and other aspects of the two verbal illusions will be compared and contrasted, and demonstrations of both will be available. [Work supported by NIH.]