Effects of word predictability, child development, and aging on time-gated speech recognition performance.

This study examined the interaction of acoustic-phonetic information with higher-level linguistic contextual information during the real-time speech perception process in child, young adult, and older adult listeners. Five age groups were studied: (a) young children ranging in age from 5 to 7 years, (b) older children aged 8 to 10 years, (c) young adults aged 18 to 23 years, (d) older adults aged 60 to 69 years, and (e) older adults aged 70 to 83 years. All subjects were presented with time-gated monosyllabic target words presented in sentence contexts containing contrasting levels of word predictability. Findings indicated that target word predictability influenced the timing and nature of the real-time recognition process including the listeners' use of initial word sounds. Predictability-high (PH) words were recognized earlier and with greater confidence than predictability-low (PL) words. PH recognition performance was more influenced by child development and aging than PL recognition performance. Older adult listeners required more PH-gated word stimuli to produce accurate responses than younger adults. Older children showed more effective use of PH contexts than younger children.