Perceptual retuning or perceptual bias? Investigating lexically guided learning across a phoneme boundary

Lexically guided perceptual learning studies have shown that speakers use their knowledge of phonemes in words to retune existing phonemic categories in response to different pronunciations. In a previous study, the authors tested whether lexically guided retuning could occur across a native category boundary, that is, when words were pronounced with an incorrect native phoneme. Monolingual Australian-English listeners completed a training phase followed by a visual lexical decision task with cross-modal priming. For participants who were trained to perceive /θ/ as /f/, /θ/-bearing auditory stimuli subsequently primed visual f-targets but not s-targets, consistent with training, but those in the /θ/=/s/ training group also showed a tendency for priming in the same direction. Here we tested whether priming would occur for the same cross-modal priming task in the absence of training. Results demonstrated a similar priming effect to that of the previous study, suggesting that the priming effects were due to a pre-existing bias to perceive /θ/ as /f/. Taken together, the two studies suggest that lexically guided retuning may not be possible across a native phoneme boundary