No available theories currently explain all adult-child cue weighting differences
Children and adults appear to weight some acoustic cues differently in perceiving certain speech contrasts. There are currently two main theories to explain this difference. One of these is the Developmental Weighting Shift theory, which proposes that children process speech in terms of more global, syllable like units. Thus, in this view, children should always give more weight than should adults to cues like within-syllable vowel formant transitions, and less weight to across-syllable vowel formant transitions . Other researchers have proposed that children have lower general auditory sensitivity than adults, which impacts on their speech perception. Thus, in this view, children should always give more weight than adults to cues that are longer, louder, or more spectrally informative than the alternative cues . The current study tested these hypotheses in two ways. First, we examined adults’ and three- to seven-year-old children’s weighting of vowel-onset formant transitions in contrasts in which we systematically varied the consonantal context and the spectral distinctiveness of the transition. Second, we examined adults’ and five-year-old children’s weighting of vowel-formant offset transitions in spectrally identical within-monosyllabic-word and across-monosyllabic-word contexts. The results of the study showed that adult-child differences in cue weighting are affected by the segmental context of the cues, the salience of the cues, and the position of the cue in the word. However, neither of the above two theories, either on their own or in combination, can account for all of the observed cue weighting behaviour.