Effects of speaker variability and phoneme location on speech perception

The effects of variation in a speaker's voice and temporal phoneme location were assessed through a series of speeded classification experiments. Listeners monitored speech syllables for target consonants or vowels. The results showed that speaker variability and phoneme-location variability had detrimental effects on classification latencies for target sounds. In addition, an interaction between variables showed that the speaker variability effect was obtained only when temporal phoneme location was fixed across trials. A subadditive decrement in latencies produced by the interaction of the two variables was also obtained, suggesting that perceptual loads may not affect perceptual adjustments to a speaker's voice in the same way that memory loads do.