Syllabic vs segmental perception: On the inability to ignore “irrelevant” stimulus parameters

C. C. Wood and R S. Day have shown that reaction times (RT) to target segments within a syllable are significantly longer when the unattended segment in the syllable (either stop consonant or vowel) is varied randomly than when it is held constant. This has been taken as evidence for the perceptual unity of a stop con sonant-vowel syllable. However, this conclusion could be accepted with much more confidence if it could be shown that random variation in unattended segments does not cause an increase in RT if the unattended segments are not in the same syllable as the target segment. The present study, using bisyllabic natural speech stimuli, (1) reconfirms Wood and Day’s results, but (2) finds that random variation in unattended nontautosyllabic segments also results in significantly longer RTs than without nontautosyllabic variation. Segmental vs syllabic speech perception thus remains an open question.