Developmental changes in the perception of syllable-final stop voicing are not explained by age-related differences in auditory sensitivity

Abstract

Two cues to voicing decisions for syllable-final stops are vocalic duration and formant transitions, especially F1, at syllable offset. Developmental studies show that children weight vocalic duration less and formant transitions more than adults. This study tested the hypothesis that age-related differences in auditory sensitivity can explain these developmental changes by measuring adults’ and children’s sensitivities to changes in the duration of nonspeech, complex tones and analogous speech stimuli. The durations of three-tone sinusoidal stimuli and natural cob and cop were varied. Duration difference limens (DLs) were similar for listeners across ages, and similar for nonspeech and speech. Also, the extent of frequency fall was varied in three-tone sinusoidal stimuli for the first tone (T1) only or for all three tones, as well as for F1 only in synthetic buck/bug. DLs for frequency extent were similar for listeners across ages for nonspeech stimuli when all three tones fell, but children had larger DLs than adults when only T1 or F1 fell, a finding contrary to labeling results showing that children weight this very property more than adults. Overall the evidence contradicted the hypothesis that age-related differences in auditory sensitivity can explain developmental changes in the perception of syllable-final stop voicing.