Signposts to Development: Theory of Mind in Deaf Children

Signposts_Child_Development

In Child Development, 2002

Signposts to Development: Theory of Mind in Deaf Children Tyron Woolfe, Stephen C. Want & Michael Siegal University of Sheffield This paper was prepared with support to TW from the Lord Snowdon Trust and the Wingate Scholarship Fund and by a Nuffield Foundation New Career Development Fellowship grant to SW and MS. We thank anonymous reviewers for their many helpful suggestions. Correspondence regarding this paper should be addressed to Michael Siegal, Department of Psychology, University of Sheffield, Western Bank, Sheffield S10 2TP, UK; E-mail: M.Siegal@Sheffield.ac.uk telephone: +44 114 222 6506, fax: +44 114 276 6515

Abstract Possession of a “theory of mind” (ToM) — as demonstrated by an understanding of the false beliefs of others — is fundamental in children’s cognitive development. A key question for debate concerns the effect of language input on ToM. In this respect, comparisons of deaf native signing children raised by deaf signing parents with deaf late signers raised by hearing parents provide a critical test. We report two studies using ‘thought picture’ measures of ToM that minimize verbal task performance requirements. These demonstrate that, even when factors such as syntax ability, mental age in spatial ability and executive functioning are considered, deaf late signers still show deficits in ToM understanding relative to deaf native signers or hearing controls. Even though the native signers were significantly younger than a sample of late signers matched for spatial mental age and scores on a test of receptive sign language ability, native signers outperformed late signers on pictorial ToM tasks. The results are discussed in terms of access to conversation and extra-linguistic influences on development such as the presence of sibling relationships, and suggest that the expression of a ToM is the end result of social understanding mediated by early conversational experience.