Seven - Hypothesis Testing
Truth and Evidence
Published online by Cambridge University Press: 05 June 2012
Summary
In 1960, British research psychologist Peter Wason reported a curious phenomenon in human reasoning. He gave his participants this simple task:
You will be given three numbers that conform to a simple rule I have in mind. This rule is concerned with a relation between any three numbers and not with their absolute magnitude, i.e., it is not a rule like all numbers greater (or less) than 50, etc.
Your aim is to discover this rule by writing down sets of three numbers, together with reasons for your choice. After you have written down each set, I shall tell you whether your numbers conform to the rule or not, and you can make a note of this outcome on the record sheet provided. There is no time limit, but you should try to discover this rule by citing the minimum number of sets of numbers.
Remember that your aim is not simply to find numbers that conform to the rule but to discover the rule itself. When you feel highly confident that you have discovered it, and not before, you are to write it down and tell me what it is.
Here are the numbers that conform to the rule I have in mind: 2 4 6
Before you continue, try to guess what the rule is. Then write down some triples that would help you find out whether or not you’re right. That is, if you showed the triples to Wason, he could tell you whether or not each one was an instance of the rule he had in mind.
Confirmation Bias: Tell Me I’m Right
If you are like the majority of Wason’s participants (54%), the rule you’re entertaining – your hypothesis – is something like “increasing intervals of two” or “consecutive even numbers.” But you would be wrong.
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- Good ThinkingSeven Powerful Ideas That Influence the Way We Think, pp. 115 - 137Publisher: Cambridge University PressPrint publication year: 2012