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Lesson
Lesson 1. Confirmation: we only look for “pros”
Understand confirmation bias — why we look for facts that confirm our view and miss the ones that refute it, and how to check for it.
Confirmation bias
We see what we already believe
Confirmation bias is the habit of looking for, noticing, and remembering what supports our opinion, and passing over what contradicts it. It may be the most important bias in the whole course: it lies at the root of many arguments, conflicts, and stubborn misconceptions.
How it works in practice:
— Once a person believes in horoscopes, they remember the times it “came true” and forget the dozens of misses.
— If we think a coworker is lazy, we notice every time he's late and don't see him staying after hours.
— Having picked a party or a blogger, we eagerly repost proof they're right and scroll past inconvenient facts.
The danger is that confirmation bias feels like objectivity: “I can see the confirmation with my own eyes!” But you see it because it's the only thing you looked for.
The antidote is the habit of deliberately asking: “What fact would prove me WRONG? And where should I look for it?” If your belief could not, even in principle, be disproved, it's not knowledge but faith.
Lesson notes
We see what we already believe
Confirmation bias is the habit of looking for, noticing, and remembering what supports our opinion, and passing over what contradicts it. It may be the most important bias in the whole course: it lies at the root of many arguments, conflicts, and stubborn misconceptions.
How it works in practice:
— Once a person believes in horoscopes, they remember the times it “came true” and forget the dozens of misses.
— If we think a coworker is lazy, we notice every time he's late and don't see him staying after hours.
— Having picked a party or a blogger, we eagerly repost proof they're right and scroll past inconvenient facts.
The danger is that confirmation bias feels like objectivity: “I can see the confirmation with my own eyes!” But you see it because it's the only thing you looked for.
The antidote is the habit of deliberately asking: “What fact would prove me WRONG? And where should I look for it?” If your belief could not, even in principle, be disproved, it's not knowledge but faith.
A classic experiment
In 1960 the psychologist Peter Wason came up with this task. I've thought of a rule that a triple of numbers follows. The triple “2, 4, 6” fits the rule. You have to guess the rule by naming your own triples; to each one I answer “fits” or “doesn't fit”.
Most people immediately decide the rule is “even numbers going up by 2” or “add 2” and start naming only confirming triples: 8-10-12, 20-22-24. Every one gets the answer “fits” — and the person confidently announces their (wrong!) rule.
The actual rule was simple: “any three numbers in increasing order”. To uncover it, you had to name a triple that DISPROVES your hypothesis, for example 1-2-3 (not going up by 2) or 6-4-2 (decreasing). But almost no one does that: we instinctively test “our” rule to confirm it, not to try to break it.
The moral: to find the truth, you have to try to disprove your idea, not pile up check marks “for” it.