The effects of context and feedback on age differences in spoken word recognition.

We investigated the hypothesis that age differences in speech discrimination would be reduced by enhancing the distinctiveness of the speech processing event in terms of both the context of encoding and the response outcome. Younger and older adults performed an auditory lexical decision task in which the degree of semantic constraint (context) and type of feedback were manipulated. Main effects of age indicated that older adults generally showed lower discriminability (D) and greater bias (B) toward reporting signals to be words. Consistent with the environmental support hypothesis, older adults were differentially facilitated in discriminability by feedback, but only when semantic context was provided. Also, for both younger and older adults, feedback and context each had the effect of reducing bias and facilitating the speed of rejecting nonwords. Contrary to one suggestion in the literature that aging brings an insensitivity to environmental contingency, older adults were at least as capable as the young in taking advantage of feedback to normalize the speech signal so as to increase discriminability and decrease bias.