According to your text, the key to solving the Wason four-card problem is:

• A. Using rote memorization of the rule
• B. Applying the falsification principle to test the rule
• C. Relying on confirmation bias to support the rule
• D. Focusing only on the cards that match the rule

Answer: (B)

Verified step by step guidance

1. Understand the Wason four-card problem: it is a logic puzzle used to study conditional reasoning, where participants must decide which cards to turn over to test a rule of the form 'If P, then Q.'
2. Recognize that the key to solving this problem is not to confirm the rule by checking cards that fit the rule, but to try to falsify it by looking for evidence that could disprove it.
3. Learn about the falsification principle, which states that to test a conditional rule 'If P, then Q,' you must check cases where P is true but Q might be false, as these can invalidate the rule.
4. Apply this principle by identifying which cards represent P and not-Q, and decide to turn over those cards to see if the rule holds or is falsified.
5. Avoid relying on confirmation bias, which is the tendency to seek out information that confirms the rule, rather than information that could disprove it.