Don’t answer this puzzle too quickly. Read the question closely, and consider your answer carefully (especially if you’ve seen this kind of puzzle before).

Sunday Puzzle #45: A Devious Selection Task

This week’s puzzle is a twist on a logic problem devised in 1966 by cognitive psychologist Peter Cathcart Wason (we’ll talk more about its origins next week). It was suggested by reader Barb G., who came across it in economist Richard Thaler’s recently published book Misbehaving: The Making of Behavioral Economics. The puzzle appears below:

On the table before you are four cards:


Your task is to turn over as few cards as possible to verify whether the following statement is true: Every card with a vowel on one side has an even number on the other side. You must decide in advance which cards you will examine.

Click here for a hint, especially if you’ve seen this kind of puzzle before.

We’ll be back next week with the solution—and a new puzzle! Got a great brainteaser, original or otherwise, that you’d like to see featured? E-mail me with your recommendations. (Be sure to include “Sunday Puzzle” in the subject line.)


SOLUTION to Sunday Puzzle #44: A Hidden Star

Last week, I asked you to find the regular, five-pointed star hidden in this illustration. For the solution, I refer you to last week’s comment section, where a number of readers highlighted, outlined, and otherwise identified the star in question.


Contact the author at Art by Tara Jacoby.