The dirty little secret of college education is that students spend countless hours acquiring knowledge that isn't very useful after you graduate (unless you stay in academia). But what is really important is the larger lessons you learn. These have to do with things like how to focus, work hard, be responsible, and think critically.
Every teacher values critical thinking skills. And we'd like to help our students develop them. But how? The intuitive answers, which most teachers adhere to, get practiced in the classroom. But rigorous scientific study shows that these techniques fail pretty spectacularly.
D. Alan Bensley has written an article in the most recent APS Observer, the trade magazine of the Association for Psychological Science, in which he provides guidelines for psychology instructors who want to teach critical thinking skills. The guidelines apply beyond psychology. It's an eye-opening read. For example, he says:
Some instructors expect their students will improve CT skills like argument analysis skills by simply immersing them in challenging course work. Others expect improvement because they use a textbook with special CT questions or modules, give lectures that critically review the literature, or have students complete written assignments. While these and other traditional techniques may help, a growing body of research suggests they are not sufficient to efficiently produce measurable changes in CT skills.
Students often find it hard to see the larger picture if teachers don't make it explicit. The teachers don't make it explicit, often, because from their perspective it's so obvious. But it's not obvious to the students. Making the process of critical thinking explicit is a perfect example of this problem.
The bottom line seems to be this: Teaching CT doesn't boil down to allowing people to observe it or try to practice it. To be effective, it seems, you actually have to teach critical thinking explicitly. And Alan Bensley's article provides advice on how to do so.