Communicating Your Way to a Theory of Mind. The development of mentalizing skills in children with atypical language development

Sammanfattning: This thesis aimed to study the development of theory of mind (ToM) in two groups of children with atypical language development, using a longitudinal design. The two groups were children with cerebral palsy and severe speech impairment (SSPI) (aged between 5 and 7 years at the first data collection) and deaf non-native, early signing, children (aged between 7 and 10 years at the first data collection), the emphasis being on the deaf children. In study I a 2-phase longitudinal study was conducted in order to explore the developmental aspects of ToM in children with SSPI. Using a three-stage developmental model of theory of mind suggested by Gopnik and Slaughter (1991) the question of deviance versus delay in the development of theory of mind was also addressed. The aim of Study II was to investigate ToM skills in non-native signing children who were offered what seems to be very good conditions for developing their language, given the lack of a signing deaf person in the home. If delays in the development of theory of mind would be found even in this group it would constitute a further strong support for the importance of conversational experience in a language common for the child and the family/caretakers. It has been argued that linguistic complexity of ToM tasks might mask a child?s underlying competence. In Study III therefore a ToM task less linguistically challenging was given to the same group of children as in study II in order to see if this would improve their results. A possible relationship between working memory, both verbal and visuo-spatial, and ToM performance was also explored. The aim of study IV was to examine the referential communication abilities in a group of non-native early signing, deaf children. A further aim was also to examine the possible role played by chronological and mental age, IQ, working memory and linguistic skill in the ability to complete the referential communication task. A comparison between referential communication and a standard theory of mind task was also done. Results from Study I indicated a non-deviant, but severely delayed ToM development in the children with SSPI. In Study II the results showed that the hearing children performed better than the deaf children on all ToM tasks and there was also very little development over time in the deaf group. Results in study III showed that lowering the linguistic demands of the ToM task did not help the deaf children. The deaf children?s performance on the spatial and verbal backward recall working memory tasks matched that of the hearing children, but they did not perform as well as the hearing children on the verbal working memory task, forward recall. Study IV showed that the hearing children were more efficient than the deaf children in the referential communication task. They also provided more relevant information and were better at judging whether enough information had been provided or not. These differences were significant and were not affected when age (chronological and mental), memory (verbal and spatial) and theory of mind was controlled for. The results speak in favour of the crucial importance of early communication using a language common for both child and family for the typical developmental trajectory of mentalizing skills, providing support for the early social-interaction hypothesis for the development of ToM. Keywords: cerebral palsy, deafness, early interaction, longitudinal design, mentalizing, theory of Mind.