The relations of desire and belief language during joint reading behaviour and theory of mind development

Recent research in the area of social development in children has looked into the causes and consequences of theory of mind (ToM) abilities. This study examined developmental patterns in both parents and children's use of different types of mental state terms during a joint reading task in a group of 2 and 3 year olds and a group of 4 and 5 year olds and their parents. Desire and cognitive mental state terms were coded from elaborations of the text of two children's books, and parent terms were classified as appropriate or not to child mental states. The current study showed that children's ToM abilities seem to encompass a relatively simple desire understanding before 4 and a more complex belief-desire understanding after 4 years of age. Furthermore, this study examined the differential role of parent's appropriate desire and cognitive mental state terms on concurrent desire, belief and total ToM understanding. It was found that parent's appropriate use of cognitive state, but not desire state, terms was significantly related to measures of children' desire and total ToM abilities in the 4 and 5 year olds. These relations held independent of socio-economic status, and children's language ability and this finding was close to significant in the 2 and 3 years olds. Implications for the developmental significance of parent's appropriate use of mental state language at different time points, and possible alternative factors affecting belief understanding, are discussed.