Discriminate acoustic cues in vowel sequence perception
John E. Kerivan, Peter J. Alfonso, Blas Espinoza-Varas · The Journal of the Acoustical Society of America · 1981
In previous reports we have described the importance of smooth pitch continuities between adjacent first formants of four synthetic vowels /i,æ,a,u/for vowel temporal order identification [Kerivan and Alfonso, J. Acoust. Soc. Am. Suppl. 1 66, S86 (1979)]. In a followup study we asked trained listeners to discriminate vowel sequences which contained differences along the following physical parameters: (1) vowel permuted order, (2) vowel and intervowel durations ranging from 15–120 ms, and (3) pitch or loudness fundamental frequency contours, natural versus flat. Using a variable standard the task was to decide whether a “comparison” sequence was in any way different from a “standard” sequence. Preliminary results indicate that listeners can reliably discriminate (d′ = 1.0) natural from flat pitch contours of vowels in sequence at vowel durations as brief as 30 ms. They can also discriminate placement of a 15 or 30 ms intervowel duration in a given sequence at similar performance levels. Vowel permuted order effects were minimal, a finding that sharply contrasts with identification of vowels in sequence. The temporal processing capabilities of trained listeners appear sufficient to discriminate dynamic ms-level changes in pitch, loudness and duration cues of very brief vowel spectra. [Work partially supported by an NINCDS NIH grant awarded to Haskins Laboratories and the University of Connecticut Research Foundation].