Confirmation Bias: How to Avoid Errors in Judgment

Imagine that you’re taking part in a psychology experiment.

The experimenter gives you a three number sequence and informs you that these numbers follow a particular rule only she knows about.

Your task is to figure out what that rule is, and you can do that by proposing your own three number strings, and asking the experimenter whether they meet the rule.

The series of numbers you’re given is:


Try It!

What underlying rule do you think these numbers follow?

And what’s another string you can give to the experimenter to see if you’re right?

If you’re like most people, you’ll assume the rule is “numbers increasing by two” or “ascending even numbers.”

To find out if you’re right, you guess something like:


And, to your delight, the experimenter says: “Yes, that string of numbers follows the rule.”

To make sure that your hypothesis is correct, you propose another sequence:


“Yes!” the experimenter says, and you confidently make your guess about the underlying rule: “Even numbers, ascending in twos!”

But, to your surprise, the experimenter says, “No!”

It turns out that the rule is “any ascending numbers.”

So, 10-12-14 and 50-52-54 fit the rule — but so does 1-2-3 or 9-748-1047.

Don’t Confirm — Disconfirm

The only way to figure that out is to guess strings of numbers that would prove your beloved hypothesis wrong — and that’s not something that comes naturally to us.

In the original study, only one in five participants guessed the correct rule.

The 2-4-6 task beautifully illustrates our bias toward confirming, rather than disproving, our ideas.

And that tendency has a massive influence on how we interpret information, form beliefs, and make decisions.

Consider, for example….

The Global Warming Controversy

Let’s say Mary believes climate change is a serious issue.

Because of that, she seeks out and reads stories about how the climate is changing.

As a result, she continues to confirm and support those beliefs.

Meanwhile, Linda does not believe that climate change is a serious issue.

Because of that, she seeks out and reads stories about how climate change is a hoax.

As a result, she continues to confirm and support those beliefs instead.

Confirming is Comfortable

The confirmation bias makes us pay attention to what supports our views and dismiss what doesn’t.

And the more convinced we become about something, the more we’ll filter out and ignore all evidence to the contrary.

It feels much better to support our beliefs than it does to discredit them.

Evaluating and adjusting our worldview is scary, uncomfortable, and strenuous. So we prefer strengthening it instead.

The confirmation bias helps us do that. But it does so at the expense of clear judgment.

Counteract the Confirmation Bias

To keep an open, flexible, and rational mind, you have to continually challenge what you think you know.

You need to deliberately seek out disconfirming evidence and always be ready to change your mind.

It’s not easy, but with practice, it will make you much better at interpreting information, updating your beliefs, and making well-informed decisions.

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