Continuity in false belief understanding from 33 to 52 months of age

Conceptual continuity in children's false belief understanding from toddlerhood to childhood was investigated in a longitudinal study of 75 children. Performance in a low-demands false belief task at 33 months of age was significantly correlated with performance in a content false belief task at 52 months independent of language ability and executive function. In contrast, there was no correlation with performance in a location false belief task, which differed from the "Sally-Anne" format of the low-demands task and was high in executive demands. These findings support the view that explicit false belief understanding may be continuous from toddlerhood to childhood and that developmental change may be characterized in terms of enrichment and increasing stability of core conceptual understanding rather than in terms of fundamental change.

Does syntax play a role in Theory of Mind development before the age of 3 years?

Language plays an important role in Theory of Mind development. Specifically, longitudinal and training studies indicate that the acquisition of complement syntax has an effect on three- to five-year-old children's mastery of the concept of false belief. There is evidence for both a beginning explicit understanding of the mind and mastery of complement syntax in children before their third birthday. In the present study, we investigated longitudinally whether an early sensitivity to complement syntax is related to early development of Theory of Mind abilities in a sample of N = 159 German-speaking 27- to 36-month-old children. Children's sensitivity to formal properties of complement syntax at 33 months was associated with their perspective-taking skills and their metacognition of own ignorance three months later. This relation remained significant when controlling for the effects of general language abilities. Furthermore, children's sensitivity to complement syntax was concurrently related to their early false belief understanding. These findings support the view that complement syntax shares representational demands with an understanding of epistemic states and that language begins to support the acquisition of epistemic concepts earlier than was previously thought.

Infants Generalize Beliefs Across Individuals

It has been argued that infants possess a rich, sophisticated theory of mind (ToM) that is only revealed with tasks based on spontaneous responses. A mature (ToM) implies the understanding that mental states are person specific. Previous studies on infants' understanding of motivational mental states, such as goals and preferences have revealed that, by 9 months of age, infants do not generalize these motivational mental states across agents. However, it remains to be determined if infants also perceive epistemic states as person specific. Therefore, the goal of the present study was to use a switch agent paradigm with the classic false belief violation-of-expectation task. Results revealed that 16-month-old infants attributed true and false beliefs to a naïve agent - they did not perceive beliefs as person specific. These findings indicate that the mechanisms that underlie infants' implicit attribution of beliefs differ from those assumed for explicit reasoning about beliefs.