Beautiful experiments in social science: Reversing the implication

People tend to make the logical error of reversing the implication, i.e. believing that "If A then B" implies "If B than A." A clever experimental design devised by psychologist Peter Cathcart Wason showed how often that mistake is made. Here's the design:

You are shown a set of four cards placed on a table, each of which has a number on one side and a colored patch on the other side. The visible faces of the cards show 1, 2, red and blue. Which card(s) should you turn over in order to test the truth of the proposition that if a card shows a 2 on one face, then its opposite face is red?

Answer given by more than 90% of participants: 2 and red. Correct answer: 2 and blue. The incorrect answer clearly stems from reversing the implication.