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Abstract

In this study we investigated perceptual learning of a foreign accent in young and elderly listeners by testing speech-perception thresholds over consecutive blocks of speech materials. Participants (20 young and 30 elderly) were first presented with four blocks of Standard Dutch sentences to establish their baseline speech-perception thresholds (SRTs). They were then presented with four sentence blocks spoken by the same speaker, but now in an artificial foreign accent of Dutch in which pronunciation of all vowel phonemes was systematically altered. We studied whether young and elderly listeners show similar-sized effects of accent on their SRTs and similar amounts of adaptation. SRTs in both age groups were higher in the accented than in the non-accented condition. In the accented condition, SRTs decreased more over blocks than in the non-accented condition, indicating that listeners adapted to the accent. Importantly, a triple interaction between speech type, block and age group indicated that the pattern of adaptation to the accent differed for the age groups: whereas the elderly hardly show further adaptation beyond the second block, the young adults do show further improvement with longer exposure. Among the elderly participants, hearing acuity predicted one's SRT and predicted the accent effect on one's SRT. Furthermore, a measure of executive function predicted the impact of the accent on one's SRT. In sum, these results indicate that accentedness is more detrimental to speech understanding in elderly than in young adults. This seems to be due both to poorer hearing and decreased mental flexibility in the elderly.