Perceptual benefits of implicit auditory learning of rule-based nonspeech sound patterns in younger and older adults

Abstract

Sounds in everyday environments typically precede and follow one another in systematic ways determined by the properties and interactions of corresponding sound sources. Familiar and predictable contextual relationships between consecutive sounds are known to provide perceptual benefit under adverse listening conditions. Previous work has demonstrated implicit learning of arbitrary rule-based sound patterns by young normal hearing adults. However, the role of such rule-based learning on identification of individual sounds within a sound pattern and the effect of listener age has not been investigated. Here younger and older adults with age-appropriate hearing were first familiarized with a set of rule-based nonspeech sound sequences produced by a finite-state machine. Subsequently, they identified individual target sounds within sequences under a range of signal-to-noise ratios (0 to -15 dB). The test sequences were (a) familiar, rule-based; (b) novel, rule-based; or (c) novel, non rule-based. The results for both younger and older listeners revealed superior sound identification in sequences versus in isolation, and a greater overall accuracy of rule-based versus non rule-based sequences. Younger listeners significantly outperformed older listeners. Implicit learning benefit did not correlate with measures of working memory processing. Current findings have implications for audiologic rehabilitation and auditory display design.