Читать книгу Philosophy of Psychology - Lisa Bortolotti - Страница 29

According to deductive logic, for a conditional statement of the form ‘If P then Q’ to be falsified, the antecedent (P) must be true and the consequent (Q) must be false. So, the statement ‘If you want to go to Brighton, then you need to catch the next train’ is false if you do want to go to Brighton but you don’t need to catch the next train.

The purpose of the selection task is to establish whether people can recognize when conditional statements are false. In the classic version of the task (Wason 1966), there is a deck of cards and each of them has a number on one side and a letter on the other. Participants can see four cards on the table, the first has a vowel (A) on the visible side, the second an odd number (7), the third a consonant (K), and the last an even number (4) (Figure 1). Participants have to say which cards they need to turn to test the following rule: ‘If a card has a vowel on one side, then it has an even number on the other side.’ Most participants in the classic version of the task said that the cards to be turned are the card with A on the visible side and the card with 4 on the visible side, or just the card with A on the visible side. However, the correct way to test the rule is to turn the card with A on the visible side and the card with 7 on the visible side, because a conditional statement is falsified when the antecedent (‘If a card has a vowel on one side’) is true and the consequent (‘then it has an even number on the other side’) is false. Only 5% of the participants solved the selection task in this version.

Figure 1. Wason selection task with abstract options