When we talk about logic and decision making in class we often use the following example: If a card shows an even number on one face, then its opposite face is blue. Which cards must you turn over in order to test the truth of his proposition, without turning over any unnecessary cards? Here is a link to a video with feedback on answer choices.
If you and your students are intrigued by this puzzle and why it is so difficult, check out this article in The Nautilus Magazine. This article provides an interesting look at the psychologist who developed this puzzle, Peter Wason, and some explanations about the puzzle and a way to illustrate the importance of context.
Psychologists Richard Griggs and James Cox put forth the hypothesis that it is the wording that makes solving this puzzle so difficult. When the they changed the wording and put it in a familiar context (trying to discover if there is an under-aged drinker) the problem became much more easy to solve.
The article also summarizes the explanation for why we struggle with this puzzle that is put forth by Daniel Kahneman in his book, Thinking, Fast and Slow. The very short version is when initially attempting this problem, our cognitive systems attempt to use "shortcuts" to make the process quicker, which leads us to making less efficient decisions. Our brains like to take shortcuts and this is highlighted by this puzzle in its original form.
Take a look at the article. It is an interesting read that can add another dimension to using this puzzle the next time you teach decision making and logic.
Let me know how else you use this puzzle. Also tell us how it goes and your thoughts about the article.