Graduation Year

2019

Document Type

Dissertation

Degree

Ph.D.

Degree Name

Doctor of Philosophy (Ph.D.)

Degree Granting Department

Communication Sciences and Disorders

Major Professor

Howard Goldstein, Ph.D., CCC-SLP

Committee Member

Jennifer Lister, Ph.D., CCC-A, FAAA

Committee Member

Amy Pace, Ph.D., CCC-SLP

Committee Member

Robert M. Barker, Ph.D.

Keywords

N400, amplitude, vocabulary, Preschoolers, ERP

Abstract

A large body of research relates families’ socioeconomic status (SES) to child language development (Hoff & Tian, 2005). Results from these studies indicate preschoolers from low SES backgrounds may have underdeveloped linguistic foundations required for future academic success (Sirin, 2005; Lacouri & Tissington, 2011). These differences have been said to create a 30 million word-gap between the language experiences of low and middle to high SES children by the age of 3 years. Thus, children who come from lower SES backgrounds often lack the vocabulary knowledge used in school and in textbooks (Hart & Risley, 1995). One index of SES is parental level of education, specifically maternal education (Hoff & Tien, 2005). The current study compared the language processes related to word knowledge of 17 preschoolers who live in lower maternal education attainment (LEA) homes and 17 preschoolers who live in higher maternal education attainment (HEA) homes. An event related potential (ERP) thought to index semantic congruity and comprehension monitoring, the N400, was used. Preschoolers listened to nouns and verbs presented aurally that matched or mismatched with pictures to understand how preschoolers from varying SES backgrounds process linguistic stimuli. Additionally, participants completed an Auditory Oddball Paradigm, or tone judgment task, to evaluate how preschoolers categorized and judged non-linguistic stimuli (e.g., standard and target pure tones). Tone judgment results revealed a Group x region midline interaction, indicating that the groups may recruit different neural resources to judge tones. The noun picture task results indicated that the HEA group processed familiar object labels more robustly and quicker than the LEA group. N400 results did not differ for the verb picture task. These results may indicate that both groups require more neural resources to process action labels and that perhaps verbs represent a higher level of linguistic complexity for young children. These results provide preliminary evidence of neural linguistic processing differences between preschoolers from varying socioeconomic backgrounds. Because of the lack of minimal differences on associated behavioral measures of language, one may speculate that ERP underpinnings as exemplified in the current study may hold promise for identifying subtle underlying differences in the processing of language among preschoolers

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