Consonant manner is thought to be perceptually robust, and fricatives categorized by frication. However, work on the /b/-/w/ contrast in American English [Shinn two pairs both containing all continua; or one pair of longerblocks containing all continua. Participants heard only one of two vowels (/a/ or /i/). Interim results do not replicate previous categorization findings: we report similarly steep responses across continua, contrasting with previous ceiling and floor effects for /b/- and /w/-amplitude continua. Free response findings do replicate, showing that longer TD induces “w” responses and ART delineates “b” and “v” responses. This suggests formant details are relevant for fricative category, and manner is more malleable after all.
Boye-Lynn et al. (Wed,) studied this question.