From an email I have just read based on a recent The Chronicle of Higher Education comes:

Steve Kolowich, in “Confuse Students to Help Them Learn”, uses the example of a physics teacher who by trying out clear versus ambiguous presentations discovered that “if you just present the correct information, five things happen…. One, students think they know it. Two, they don’t pay their utmost attention. Three, they don’t recognize that what was presented differs from what they were already thinking. Four, they don’t learn a thing. And five, perhaps most troublingly, they get more confident in the ideas they were thinking before.”