I wonder if instead, kids simply learn it as their brains mature. That is, maybe the repetition does nothing but annoy everyone. There are all sorts of studies that show that brains continue to mature even into the twenties. When, as a kid, I heard the phrase "Think before you act", it was usually not in the context of major life decisions -- it was in the context of measure-twice-cut-once situations. To be fair, some of these could turn out to be major life decisions (i.e. diving head-first into an insufficiently deep pool), but they aren't intended to be so.
I am going to do Splash! Fall 2011 at the University of Chicago, where I chose a subject to teach kids. I'm teaching a 1 hour class on the basics on rationality, and I am outlining the topics I want to cover.
Right now, I'm planning on teaching map and territory, reductionism, a basic introduction to biases, and what having a belief should mean (paying rent).
What other ideas would be useful to teach high school students? And does anyone have suggestions on interesting ways to teach these concepts?
Edit: All comments say four is too many topics, I will focus on map and territory and beliefs paying rent.