Dissociating the Impact of Auditory Access and Language Access in Deaf Children’s Cognitive Development
Deaf and hard of hearing (DHH) children have been claimed to lag behind their hearing peers in various domains of cognitive development, especially in implicit learning, executive function, and working memory. Two major accounts of these deficits have been proposed: one based on a lack of auditory access, and one based on a lack of language access. This chapter reviews these theories in relation to the available evidence and concludes that there is little evidence of direct effects of diminished auditory access on cognitive development that could not also be explained by diminished language access. Specifically, reports of deficits in implicit learning are not broadly replicable. Some differences in executive function do stem from deafness itself but are not necessarily deficits. Where clinically relevant deficits in executive function are observed, they are inconsistent with the predictions of accounts based on auditory access, but consistent with accounts based on language access. Deaf–hearing differences on verbal working memory tasks may indicate problems with perception and/or language, rather than with working memory. Deaf–hearing differences on nonverbal tasks are more consistent with accounts based on language access, but much more study is needed in this area. The chapter concludes by considering the implications of these findings for psychological theory and for clinical/educational practice and by identifying high-priority targets for future research.