Graduation Year

2012

Document Type

Thesis

Degree

M.S.

Degree Granting Department

Communication Sciences and Disorders

Major Professor

Nathan D. Maxfield

Keywords

activation spreading, age-related decline, event related potentials, lexical access, phonological processing, semantic interference

Abstract

Objective: The aim of the present study was to investigate the mechanics with which older adults activate and access different subdomains of their mental lexicons during word retrieval for picture naming.

Method: Data were analyzed for 12 aging, native English speakers who performed a picture-word priming task. The auditory probe words were presented in the following conditions in relation to the picture stimuli: Identically related, strongly semantically related, weakly semantically related, strongly phonologically related, weakly phonologically related, semantically related to the strong phonological relative of the target picture label, or phonologically-related to the strong semantic relative of the target picture label. Event related potentials were used to measure picture-word priming effects.

Results: Three main results were observed. First, our healthy aging adult participants evidenced strong activation of whole-word phonological representations as well as rhyme representations of target picture labels, but weakened activation of initial phoneme information. Second, they processed semantic information robustly. Finally, our participants appeared to experience phonological competition when accessing target picture labels.

Conclusion: Results from this study suggest that healthy aging adults maintain efficient access to whole-word phonological representations, rhyme representations, and conceptual-semantic representations of target picture labels. However, in line with previously-reported findings, they do seem to evidence limited activation of initial phonological information on the path to picture naming.

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