Effects of talker variability on categorization of spectrally degraded vowels.

When a person listens to a context sentence with prominent higher frequencies, the subsequent vowel sound is more likely to be perceived as being of a lower frequency and vice versa. This is a spectral contrast effect (SCE). Recent work has shown that talker variability diminishes these SCEs. They were found to be smaller when 200 sentences were spoken by a different talker each time compared to one talker (Assgari & Stilp, 2015). Cochlear Implant (CI) users’ speech categorization is also influenced by SCEs but are known to struggle with talker discrimination. Here, I tested whether talker variability affected SCEs when the speech was spectrally degraded. Listeners indicated whether they heard “ih” (as in bit) or “eh” (as in bet) following 200 context sentences spoken by the same talker or varying talkers (Assgari & Stilp, 2015). The sentences were noise vocoded to broadly simulate CI processing. SCEs occurred but did not significantly differ across one-talker and 200-talker conditions. Talker variability does not appear to affect perception in acoustic simulations of CI processing in the same way it does for normal-hearing listeners