Labeling of /s/ and [see text] by listeners with normal and impaired hearing, revisited

The two aims of this study were (a) to determine the perceptual weight given formant transition and relative amplitude information for labeling fricative place of articulation perception and (b) to determine the extent of integration of relative amplitude and formant transition cues. Seven listeners with normal hearing and 7 listeners with sensorineural hearing loss participated. The listeners were asked to label the fricatives of synthetic consonant-vowel stimuli as either /s/ or [see text]. Across the stimuli, 3 cues were varied: (a) The amplitude of the spectral peak in the 2500-Hz range of the frication relative to the adjacent vowel peak amplitude in the same frequency region, (b) the frication duration, which was either 50 or 140 ms, and (c) the second formant transition onset frequency, which was varied from 1200 to 1800 Hz. An analysis of variance model was used to determine weightings for the relative amplitude and transition cues for the different frication duration conditions. A 30-ms gap of silence was inserted between the frication and vocalic portions of the stimuli, with the intent that a temporal separation of frication and transition information might affect how the cues were integrated. The weighting given transition or relative amplitude differed between the listening groups and depended on frication duration. Use of the transition cue was most affected by insertion of the silent gap. Listeners with hearing loss had smaller interaction terms for the cues than listeners with normal hearing, suggesting less integration of cues.