Explicit theory of mind is even more unified than previously assumed: belief ascription and understanding aspectuality emerge together in development.

Existing evidence suggests that children, when they first pass standard theory-of-mind tasks, still fail to understand the essential aspectuality of beliefs and other propositional attitudes: such attitudes refer to objects only under specific aspects. Oedipus, for example, believes Yocaste (his mother) is beautiful, but this does not imply that he believes his mother is beautiful. In three experiments, 3- to 6-year-olds' (N = 119) understanding of aspectuality was tested with a novel, radically simplified task. In contrast to all previous findings, this task was as difficult as and highly correlated with a standard false belief task. This suggests that a conceptual capacity more unified than previously assumed emerges around ages 4-5, a full-fledged metarepresentational scheme of propositional attitudes.