ASA 129th Meeting - Washington, DC - 1995 May 30 .. Jun 06

4aSC5. Lexical influence on the perception and segmentation of speech: Evidence from the migration paradigm.

Sven L. Mattys

Arthur G. Samuel

Dept. of Psych., SUNY at Stony Brook, Stony Brook, NY 11794-2500

The present study addresses the issue of lexical influence on perception through a new paradigm based on the migration of linguistic units from one ear to the other when two stimuli are presented dichotically. For example, ``dentast'' and ``kolbisk'' could be presented dichotically, with subjects judging if ``dentist'' was presented. The migration of the vowel, leading to erroneous perception of a pre-specified target, occurred less often with word targets than with nonsense word targets. This result indicate that the lexical representation of a signal imposes some restriction on the acoustic-phonetic stage of processing of the signal. Furthermore, when the two items of the pairs were played binaurally rather than dichotically, the migration rate increased substantially, but the size of the lexical effect remained unchanged. However, the lexical effect disappeared when the migrating vowel was located in the stressed syllable of the stimuli. In this condition, the lexical resistance collapses and words become as susceptible to migrations as nonsense words. This second result may suggest that lexical access is initiated on strong syllables of words: when the stressed syllable is mispronounced, lexical access is impaired, eliminating the lexical effect. [Work supported by AFOSR, NIMH, and BAEF.]