Informational masking and the effects of differences in fundamental frequency and fundamental-frequency contour on phonetic integration in a formant ensemble.
This study explored the effects on speech intelligibility of across-formant differences in fundamental frequency (ΔF0) and F0 contour. Sentence-length speech analogues were presented dichotically (left = F1+F3; right = F2), either alone or-because competition usually reveals grouping cues most clearly-accompanied in the left ear by a competitor for F2 (F2C) that listeners must reject to optimize recognition. F2C was created by inverting the F2 frequency contour. In experiment 1, all left-ear formants shared the same constant F0 and ΔF0F2was 0 or ±4 semitones. In experiment 2, all left-ear formants shared the natural F0 contour and that for F2 was natural, constant, exaggerated, or inverted. Adding F2C lowered keyword scores, presumably because of informational masking. The results for experiment 1 were complicated by effects associated with the direction of ΔF0F2; this problem was avoided in experiment 2 because all four F0 contours had the same geometric mean frequency. When the target formants were presented alone, scores were relatively high and did not depend on the F0F2contour. F2C impact was greater when F2 had a different F0 contour from the other formants. This effect was a direct consequence of the associated ΔF0; the F0F2contour per se did not influence competitor impact.
Psychology, School of Life and Health Sciences, Aston University, Birmingham B4 7ET, UK.
Robert J
RJ
Summers
Department of Psychology, University of York, Heslington, York YO10 5DD, UK.
Peter J
PJ
Bailey
Psychology, School of Life and Health Sciences, Aston University, Birmingham B4 7ET, UK. Electronic address: b.roberts@aston.ac.uk.
Brian
B
Roberts
D000161:Acoustic Stimulation; D000162:Acoustics; D000293:Adolescent; D000328:Adult; D001302:Audiometry, Speech; D005260:Female; D006801:Humans; D008297:Male; D009622:Noise / Q000009:adverse effects*; D010470:Perceptual Masking; D010700:Phonetics; D021641:Recognition, Psychology; D013018:Sound Spectrography; D013061:Speech Acoustics; D013065:Speech Intelligibility; D013067:Speech Perception; D014833:Voice Quality; D055815:Young Adult
Competition; Formant integration; Informational masking; Speech intelligibility; Speech segregation; Target-masker similarity