Date of Award

Spring 1-1-2012

Document Type

Thesis

Degree Name

Master of Arts (MA)

Department

Speech, Language & Hearing Sciences

First Advisor

Phillip Gilley

Second Advisor

Brenda Schick

Third Advisor

Jeff Coady

Abstract

This study sought to compare classification of words and syllables using the P3 response of the auditory event related potential (ERP) as an index of speed of classification. In this study, we measured ERPs and behavioral reaction times to auditory stimuli consisting of three-phoneme words (e.g. /bæd/) and two-phoneme syllables (e.g. /bæ/) in ten young adults. Stimuli were presented in an auditory odd-ball paradigm under two experimental conditions (words-rare and syllables-rare), presented monaurally and repeated in each ear. Using planned comparisons on the PZ electrode, and controlling for ear, condition was a significant predictor of latency with earlier P3 latencies in the words-rare condition. This is consistent with the behavioral data revealing faster responses to words than to syllables. The interaction of ear and condition was significant with participants having earlier P3 latencies on average in their left ear in the syllables-rare condition, and earlier P3 latencies on average in their right ear in the words-rare condition. The right ear advantage was present in the P3 response to words; however, the response to syllables did not show this advantage. The difference in P3 latencies suggests that classification occurs faster for words than for syllables, and may suggest that the latency of the P3 response reflects the behavioral relevance of the stimulus.

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