Expectation and Entropy in Spoken Word Recognition: Effects of Age and Hearing Acuity

Background/Study Context: Older adults, especially those with reduced hearing acuity, can make good use of linguistic context in word recognition. Less is known about the effects of the weighted distribution of probable target and nontarget words that fit the sentence context (response entropy). The present study examined the effects of age, hearing acuity, linguistic context, and response entropy on spoken word recognition. Methods: Participants were 18 older adults with good hearing acuity (M-age=74.3 years), 18 older adults with mild-to-moderate hearing loss (M-age=76.1 years), and 18 young adults with age-normal hearing (M-age=19.6 years). Participants heard sentence-final words using a word-onset gating paradigm, in which words were heard with increasing amounts of onset information until they could be correctly identified. Degrees of context varied from a neutral context to a high context condition. Results: Older adults with poor hearing acuity required a greater amount of word onset information for recognition of words when heard in a neutral context compared with older adults with good hearing acuity and young adults. This difference progressively decreased with an increase in words' contextual probability. Unlike the young adults, both older adult groups' word recognition thresholds were sensitive to response entropy. Response entropy was not affected by hearing acuity. Conclusion: Increasing linguistic context mitigates the negative effect of age and hearing loss on word recognition. The effect of response entropy on older adults' word recognition is discussed in terms of an age-related inhibition deficit.