It's a case where children are repeating back what the teacher did, rather than developing a deeper understanding of how the world is. And the other experimental condition shows that the children are capable of developing a deeper understanding.

The children still do have a genuine belief about the external world (they expect the three-step process to produce music), so it's not the most degenerate case of simply parroting words that are meaningless to them, but it still seems to be on the path described in Eliezer's two posts.