of the Annual Meeting of the Cognitive Science Society Title Expressions Related to Knowledge and Belief in Children ’ s Speech Permalink

Children develop certain abilities related to Theory of Mind reasoning, particularly concerning the False-belief Task, between the ages of 3 and 5. This paper investigates whether there is a corresponding change in the frequency of linguistic expressions related to knowledge and belief produced by children around these ages. Automated corpus analysis techniques are used to tag each expression related to knowledge and belief in a large corpus of transcripts of speech from normally developing English-learning children. Results indicate that the frequency of expressions related to knowledge and belief increases steadily from the beginning of children’s language production. Tracking of individual concepts related to knowledge and belief indicates that there are no clear qualitative changes in the set of concepts that are expressed by children of different ages. The implications for the relationship between language and the development of Theory of Mind reasoning abilities in children are discussed. A Developing Theory of Mind Among the most interesting of human cognitive abilities are those concerning how we understand and reason about the minds of others. The term Theory of Mind is used pervasively throughout the cognitive sciences to refer to the set of abilities that enable people to reflect introspectively on their own reasoning, to empathize with other people by imagining what it would be like to be in their position, and to generate reasonable expectations and inferences about mental states and processes. Within the research area of developmental psychology, Theory of Mind has been studied as a set of cognitive abilities that progressively emerge in children. A standard experimental instrument for studying children's Theory of Mind abilities is the false-belief task. In a standard version of this task (Wimmer & Perner, 1983), the child is introduced to two characters, Maxi and his mother. Maxi places an object of interest into a cupboard, and then leaves the scene. While he is away, his mother removes the object from the cupboard and places it in a drawer. The child is then asked to predict where Maxi will look for the object when he returns to the scene. Success on this task has been criticized as neither entirely dependent on Theory of Mind abilities nor broadly representative of them (Bloom & German, 2000), however its utility has been in reliably demonstrating a developmental shift. Wellman et al. (2001) analyzed 178 separate studies that employed a version of this task, finding that 3-year-olds will consistently fail this task on the majority of trials by indicating that Maxi will look for the object in the location to which his mother has moved it. 4-year-olds will succeed on half the trials, while 5-year-olds will succeed on the majority of trials. Call & Tomasello (1999) demonstrate that these results are consistent across verbal and non-verbal versions of this task. Children’s developing performance on the false-belief task is particularly interesting when couched within the larger debate concerning maturation and. conceptual change in cognitive development. Like every other cognitive ability that emerges in childhood, performance on Theory of Mind tasks is likely due to a complex combination of maturing innate abilities and knowledge learned through experience. Still, understanding the relative importance of these two factors may have some utility in evaluating two types of cognitive process models that have been proposed to account for human Theory of Mind abilities. First, Theory Theory hypothesizes that Theory of Mind abilities are computed by prediction and explanation mechanisms by employing representation-level knowledge about mental attitudes (Gopnik & Meltzoff, 1997; Nichols & Stich, 2002). Second, Simulation Theory argues that Theory of Mind abilities are computed by imagining that you are in the place of the other person, then inferring their mental states by monitoring the processing that is done by your own cognitive abilities (Goldman, 2000). With respect to the development of Theory of Mind abilities in children, each of these theories would emphasize different things as most important. Theory Theorists would argue that the acquisition of mental models of commonsense psychology would play the most important role, a view consistent with a conceptual change model of development (e.g. Bartsch & Wellman, 1995). In contrast, Simulation Theorists would look instead for a maturational change that enabled children to take the perspective of other people or in the monitoring of one’s own mental state, a view consistent with a modularity model of development (e.g. Scholl & Leslie, 2001). One approach to investigating this issue is to look for evidence of the acquisition of mental models of commonsense psychology in the language that children use in everyday conversation. The contemporary view of natural language understanding and generation presupposes that the meaning of verbal expressions are representational in nature, and that these underlying representations are the same ones that would be manipulated for the purposes of inference (e.g. explanation and prediction). By tracking the production of children’s speech that references commonsense psychology concepts, we can look for some correlation between linguistic competency with commonsense psychology concepts and emerging Theory of Mind abilities.