Listeners heard an ambiguous /f-s/ in nonword contexts where only one of /f/ or /s/ was legal (e.g., frul/*srul or *fnud/snud). In later categorisation of a phonetic continuum from /f/ to /s/, their category boundaries had shifted; hearing -rul led to expanded /f/ categories, -nud expanded /s/. Thus phonotactic sequence information alone induces perceptual retuning of phoneme category boundaries; lexical access is not required.
Bibliographic reference. Cutler, Anne / McQueen, James M. / Butterfield, Sally / Norris, Dennis (2008): "Prelexically-driven perceptual retuning of phoneme boundaries", In INTERSPEECH-2008, 2056.