A spatial gradient in phonetic recalibration by lipread speech

Exposure to ambiguous speech combined with clear lipread speech can recalibrate auditory speech identification, a phenomenon known as phonetic recalibration (Bertelson, Vroomen, & De Gelder, 2003). Here, we examined whether phonetic recalibration is spatially specific. Participants were presented an ambiguous auditory sound halfway between /b/ and /d/ (A?) combined with lipread /b/ or /d/ at either the left or right ear/side, and were subsequently tested with auditory-only test sounds at either the same or the opposite ear/side. Phonetic recalibration was always strongest if test sounds were presented at the same ear/side than if they were presented at a different ear/side. Phonetic recalibration thus has a spatial gradient, showing that stimulus-specific and non-linguistic factors contribute to this phenomenon.