Date on Master's Thesis/Doctoral Dissertation

5-2013

Document Type

Doctoral Dissertation

Degree Name

Ph. D.

Department

Psychological and Brain Sciences

Committee Chair

Wightman, Fred

Committee Co-Chair (if applicable)

Houston, Derek

Subject

Deaf children--Language; Hearing impaired children--Language; Language awareness in children; Deafness in children--Language; Cochlear implants

Abstract

The first aim of this dissertation was to determine whether early deafness is related to children's nonverbal cognitive abilities. Performance of a group of deaf infants were compared to that of same-aged hearing infants on visual sequence learning (VSL) and visual recognition memory (VRM) tasks. The hypothesis was that if deafness is negatively related to general cognitive ability, then the deaf infants would perform more poorly than same-aged hearing infants on the two tasks. There were no significant differences in VSL (n = 19) or VRM (n = 13) performance between the two groups (Chapter III). These results are inconclusive due to the small sample sizes, but importantly, there were individual infants in both groups who demonstrated learning on the two nonverbal tasks. The second aim was to determine whether VSL and VRM ability can provide predictive information about spoken language development. The results for the normal hearing 8.5-month-olds provide evidence for a significant relation between VSL ability and spoken language outcomes (Chapter IV). Specifically, it was found that sequence learning (thought to rely on procedural memory ability) may contribute to vocabulary and gestural development in normal-hearing infants. Further research with larger samples of infants is needed to determine whether procedural learning may be important for grammar acquisition. These results suggest that VSL ability may not be related to spoken language outcomes for deaf infants who use cochlear implants (Chapter V), although VRM ability may be (Chapter VI). If this pattern of results held up for a larger sample of deaf infants, this would suggest that the nonverbal cognitive abilities tapped in the VSL and VRM tasks are not critical for at least some aspects of spoken language development in deaf children who use cochlear implants, and that potential deficits in nonverbal cognitive ability are not necessarily associated with poorer spoken language ability in this population. In future research a larger sample of deaf infants should be recruited in order to clarify whether nonverbal cognitive skills are related to early deafness, and how those nonverbal skills might relate to spoken language development in this unique population.

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