Smart people believe some pretty ridiculous things. Oh... not me! Right? That's the uncomfortable part.

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We tend to imagine intelligence as a kind of mental security system. Give a smart person enough information and surely they'll spot the holes, question the contradictions, and politely escort the nonsense to the door. Unfortunately, the human brain didn't get that memo.

 

Being intelligent can make us good at evaluating evidence.

But it can also make us exceptionally good at defending what we already believe.

 

Think about something you've believed since childhood. Maybe it came from your parents. Your religion. Your culture. Your teachers. Chances are, nobody sat five-year-old you down with competing arguments and said, Take your time. Review the evidence. You absorbed it. And that's how many beliefs begin—not with evidence, but with trust. Then something else happens.

 

We find people who agree with us. That's comforting. We listen to them. We read what they read. We notice information that confirms what we already believe and find perfectly reasonable explanations for information that doesn't. Psychologists call this confirmation bias.

 

Repetition helps, too. Researchers have repeatedly found that statements can begin to feel more truthful simply because we've encountered them before. Psychologists call this the illusory truth effect. Apparently, the brain occasionally mistakes I've heard that before for I've investigated that thoroughly.

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Then there's belonging. Humans are social creatures. For most of our history, being rejected by our group wasn't merely uncomfortable. It could be dangerous. We still carry some of that wiring around with us.

 

So questioning a belief can mean much more than changing our minds.

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What if changing my mind disappoints my parents?

What if my friends think I've lost it?

What if my church rejects me?

What if my colleagues stop respecting me?

What if I have to admit I've been wrong for thirty years?

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Suddenly, we're no longer evaluating an idea. We're evaluating the price of questioning it. And here's where intelligent people can get themselves into particular trouble.

 

The better we are at reasoning, the better we may also be at constructing arguments for the conclusion we want to reach.

 

Instead of asking, Is this true? we can quietly begin asking, How can I prove this is true? Those are very different questions. None of this means we're helpless—or that every inherited belief is wrong. Plenty of things our parents, teachers, religions and communities taught us may withstand scrutiny beautifully.

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Perhaps intelligence isn't measured only by how effectively we can defend what we believe. Maybe occasionally it's measured by our willingness to turn around, look directly at something we've believed for years, and ask one deceptively simple question:

How do I know this is true?