Do deaf adults with limited language have advanced theory of mind?

Abstract

Previous studies show that deaf children have deficits in false belief understanding due to their language impairment. However, it is not clear whether deaf adults still have problems in advanced theory of mind (ToM). The present study examined deaf adults' performance on three aspects of advanced ToM. All of the deaf groups lacking mental state language tended to perform worse than the hearing group on explicit mental state understanding. Deaf groups with either vocabulary skill or interpersonal experience from early years were similar to the hearing group in implicit mental state reasoning. Individuals frequently using syntactic complements or having interpersonal experience with hearing people from early years tended to use ToM better. Moreover, language ability was the only predictor for explicit rather than implicit mental state understanding. Sufficient language is not necessary for all aspects of advanced ToM. Rich interpersonal experience as a substitute for language may facilitate deaf adults' advanced ToM.