“…Second, by the beginning of formal schooling, children already have an abstract understanding of what constitutes informative teaching (i.e., the information communicated should be accurate, su cient, yet not superfluous), and readily evaluate others' teaching accordingly 19,20,21,22,23 . As teachers themselves, children can also tailor the content of their communication based on the learner's goal or knowledge state 24,25,26 , readily selecting appropriate evidence to communicate a concept 27 , correct others' false beliefs 28 , or disambiguate a causal system 29,22 . In particular, when evidence is physically costly to generate (e.g., demonstration requires multiple actions or walking over a distance), 5-to 6-year-olds resist providing unnecessary information 29,22 , suggesting that children are sensitive not only to the value of information but also the cost of generating it.…”