The Confirmation Bias

Let’s try the Wason Selection Task.

Rule: If a card has a star on one side, it has an even number on the other side.

Which cards should you flip to check if the rule holds true?

The common mistake that people make is to flip the 4 to check if there is a star on the other side. However, that flip is not going to be informative because there is no way for any result to break the rule.

Either there is a star or no star on the other side, the rule is good. The rule did not mention what goes with non-star shapes.

Flipping the 4 can only show that the rule is right, not wrong.

Rule: If (Star), then (Even)

The opposite would be if (Not Star), then (Not Even).

What we should do is to disconfirm the rule. The cards that you should flip to check are the star & 3.

If you flipped the 4, you may have fallen prey to the confirmation bias, a term coined by psychologist Peter Wason.

What is Confirmation Bias?

Confirmation bias is the tendency to look for evidence, information, and favor that confirms and supports our pre-existing beliefs. We look for reasons why we are right, not reasons why we are wrong.

The human tendency is that we want to confirm what we already know and believe rather than disconfirm it. More often than not, we fall prey to confirmation bias at some point in our lives.

For example, if all the birds you have seen so far are white, discovering another white bird will not prove the theory that “all birds are white” to be confirmed truth. There could possibly be other colored birds out there that have yet to be found, which we need to look for as evidence to support the theory.

Another example, people who support or oppose a particular issue tend to seek information that supports it and interpret news stories in a way that upholds their existing beliefs.

What you should do instead is to actively seek out information that disconfirms and contradicts your beliefs rather than those that support it. When you’re willing to be wrong, you open yourself up to new perspectives. Focus less on being right, embrace disagreement, and surround yourself with a variety of viewpoints on every aspect of life.