It has been argued that the distinction between factivity and non-factivity is more fundamental to mental state understanding than that between false beliefs and reality. The present study examined children's growing understanding of all possible contrasts between the factive verb "know" and the non-factive verbs "think" and…

First-order theory of mind (ToM) development has shown to conform to a Guttman scale, with desire reasoning developing before belief reasoning. There have been attempts to test for internal consistency and scalability in advanced ToM, but not over a broad age range and only with a limited set of tasks. This 2-year longitudinal study (N = 155;…