ASA 124th Meeting New Orleans 1992 October

5aSP1. Effects of first formant onset frequency on voicing judgments result from auditory processes not specific to humans.

Andrew J. Lotto

Keith R. Kluender

Dept. of Psychol., Univ. of Wisconsin, 1202 W. Johnson St., Madison, WI 53706

When Fl onset frequency is lower, a longer F1 cutback (VOT) is required for human listeners to perceive synthesized stop consonants as voiceless. K. R. Kluender [J. Acoust. Soc. Am. 90, 83--96 (1991)] found comparable effects of F1 onset frequency on the ``labeling'' of stop consonants by Japanese quail (Coturnix coturnix japonica) trained to distinguish stop consonants varying in F1 cutback. In that study, CV's were synthesized with natural-like rising F1 transitions. Consequently, endpoint training stimuli (with 5- or 65-ms F1 cutback) differed in the onset frequency of F1 because a longer cutback resulted in a higher F1 onset. In order to assess whether earlier results were due to auditory predispositions or due to animals learning the covariance between F1 cutback and F1 onset frequency, the present experiment was conducted with synthetic continua having either a relatively low (375-Hz) or high (750-Hz) constant-frequency F1. Eight birds were trained to respond differentially to endpoint stimuli from three series of synthesized /Ca/'s varying in duration of F1 cutback. Second and third format transitions were appropriate for labial, alveolar, or velar stops. Despite the fact that there was no opportunity to use experienced covariation of F1 onset frequency and F1 cutback, quail exhibited reliably shorter ``labeling'' boundaries (more voiceless stops) for intermediate stimuli of the continua when F1 frequency was higher. Human performance with the same stimuli was like that for the birds. These results support the conclusion that the effect of F1 onset frequency may be adequately explained by general auditory processes. [Work supported by NIDCD/NIH Grant No. DC-00719.]