Non-native consonant acquisition in noise: Effects of exposure/test similarity

When faced with speech in noise, do listeners rely on robust cues or can they make use of joint speech-plus-noise patterns based on prior experience? Recent studies have suggested that listeners are better able to identify words in noise if they experienced the same word-in-noise tokens in an earlier exposure phase. The current study examines the role of token similarity in exposure and test conditions. In three experiments, Spanish learners of English were exposed to intervocalic consonants during an extensive training phase, bracketed by pre- and post-tests. Distinct cohorts experienced tokens that were either matched or mismatched across test and training phases in one or both of two factors: signal-to-noise ratio (SNR) and talker. Cohorts with fully matching test-training exposure were no better at identifying consonants at the post-test phase than those trained in partially or fully mismatched conditions. Indeed, at more adverse test SNRs, training at more favourable SNRs was beneficial. These findings argue against the use of joint speech-plus-noise representations at the segmental level and instead suggest that listeners are able to extract useful acoustic-phonetic information across a range of exposure conditions.