The Confirmation Bias

Imagine that each square below represents a card. Suppose that you are participating in a study in which the experimenter tells you that every card has a letter on one side and a number on the other side.

You are then given this rule about these four cards: ‘‘IF A CARD HAS A VOWEL ON ONE SIDE, THEN IT HAS AN EVEN NUMBER ON THE OTHER SIDE.’’

Your task is to decide which card (or cards) you would need to turn over, so that you can find out whether this rule is valid or invalid. What is your answer? The correct answer is discussed later in the chapter.

(Incidentally, the answer to the problem about the objects on p. 415 is‘‘valid.’’)