Overview
The Wason selection task is the most studied experiment in the psychology of reasoning. Most people test a rule by confirming it, when logic demands you try to break it.
How to solve The Wason Selection Task
- The rule 'vowel ⇒ even' can only be broken by a vowel with an odd number behind it.
- Flip the vowel (A) to check its number, and flip the odd number (7) to check its letter.
- The consonant (K) and the even number (4) can never violate the rule, so leave them.
The key insight
Test the cases that could falsify the rule, not those that could confirm it. Flipping the '4' feels productive but no result there can ever break a vowel⇒even rule.
Variations & echoes
- People solve the identical logic far better when it's framed as catching rule-breakers (e.g. underage drinking).
- It illustrates confirmation bias — our pull toward evidence that agrees with us.
Frequently asked questions
Why not flip the 4?
The rule doesn't claim even numbers have vowels. Whatever letter is behind the 4, the rule stays intact — so flipping it tests nothing.