The Perversity of Self-Referential Teaching

When I taught my students version one of the Fundamental Theorem of Calculus (the one which tells you how to take derivatives of functions involving integrals), I said:

Isn't this easy? Don't you wish the whole test was going to be this? Well, I will go ahead and tell you that when I put one of these problems on the exam, half of you will forget and miss it.

I say this every time I teach the section, in the hopes that it might make the material stick. This time I went one step further and added:

That will be true despite the fact that I have just told you this.

I thought possibly that this statement might make at least a few more students decide to remember it. (It seemed to make an impression at least; they did laugh.)

Well I gave the exam this morning, and it turns out that in fact more than half the class forgot it. I think somewhere around 80% forgot it. Maybe next time I will try: "Everyone gets this problem every time, so don't bother to study this at all."