Wason Selection


The human mind is often likened to a computer, but do humans really think like computers 'think'? One test of this analogy is to look at how well humans deal with conditional statements such as "If A, then B". Computer programs are structured around conditional statements and when given one a computer will never make an error, thus if humans are like computers, they should never make mistakes with conditional statements either.... One of the first experimental studies of human conditional reasoning was reported by Wason (1966) using what is known as 'the Wason selection task'. First you will try the 'selection task' yourself a number of times, then we will consider general results from conditional reasoning experiments and their implications for our understanding of human cognition.

Review Question

Question: Suppose you presented participants in an experiment with the problem "if you get a flu shot you will not get the flu" and then gave them two options... testing the hypothesis by studying people who did not get the flu last year, or testing the hypothesis but studying people who got the flu shot, which approach do you think MOST of your participants would choose and why?

Answer: Most would probably study people who did not get the flu because of 'confirmation bias'. This is the incorrect approach. The best way to study this problem is to try to prove the theory wrong: study people who got the shot and look for cases where they did get the flu.

Question: Some researchers have argued that humans have not evolved the ability to reason conditionally but have evolved the ability to catch people violating rules. What aspect of typical results from Wason selection tasks supports this hypothesis?

Answer: Most people have difficulty with the Wason selection task when the rule the cards must follow is abstract (e.g. if there is a square on one side there must be a vowel on the other) while having little difficulty with the selection task when the rule cards must follow is related to following a social rule (e.g. if the person is at an R movie they must be 18).