Dissertations, Theses, and Capstone Projects

Date of Degree

6-2014

Document Type

Dissertation

Degree Name

Ph.D.

Program

Speech-Language-Hearing Sciences

Advisor

Richard G. Schwartz

Subject Categories

Cognitive Psychology | Linguistics | Other Languages, Societies, and Cultures

Keywords

Adults, Lexical Access, Lexical Restructuring, Phonological Neighborhood Density, Specific Language Impairment

Abstract

The present study was designed to examine how adults, children with typical language development (TLD), and children with Specific Language Impairment (SLI) process words from sparse and dense phonological neighborhoods, using the Cross Modal Picture-Word Interference Paradigm. The participants were asked to label a picture presented on a computer screen, while ignoring auditory distractors (interfering words or IWs) presented over headphones. The target items were manipulated according to neighborhood density (high and low density words), and the auditory distractors were either identical to the target, a neutral distractor (good), phonologically related (by rhyme), or unrelated to the target item. The interfering words were presented either before the target item ( -750, -450, or -150 ms ) before the picture, or after the picture ( +150 ms ). Participants were asked to name the pictures as quickly as possible, while ignoring the auditory distractors. Reaction times and error rates were measured.

Eleven children with SLI (6;5-10;1), ten children with typical language development (6;10-10;2), and 22 young adults participated in the study. The results revealed that adults demonstrated increased sensitivity to rhyme-related distractors in the Low Density condition only, reflecting less detailed phonological representations of low density words. Children with TLD and SLI both demonstrated less interference of related IWs in both the high and low density conditions. There were no significant group differences in reaction time or overall error rates. However, the SLI group produced significantly more errors on low density words than the TLD group. In addition, children with SLI demonstrated similar response time differences for the related and unrelated items for both density types, while the children with TLD appeared to benefit more from the related distractors in the low density condition. The results are discussed in relation to the Lexical Restructuring Model (Metsala & Walley, 1998).

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