Module 5 · Making decisions · Lesson 6 of 10

Traps in what you notice

Confirmation bias, anchoring and availability: the mind’s shortcuts about what counts as evidence.

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The idea

The mind uses shortcuts to decide what counts as evidence. They are usually helpful — without them, every decision would take forever — but in some situations they mislead in predictable ways. Three are especially common.

Confirmation bias is noticing and believing information that fits what you already think, and overlooking what does not. Anchoring is being pulled toward the first number or idea you hear: a price, a salary, an estimate. The availability bias is judging how likely something is by how easily examples come to mind — so vivid news stories feel more common than they are.

Nobody can switch these off. What helps is knowing them well enough to ask a few simple questions: What would I expect to see if I were wrong? Where did this first number come from? Is this common, or just memorable?

Why it matters

These shortcuts quietly shape decisions about money, health, relationships and work. Catching them even occasionally can prevent expensive or painful mistakes.

See it happen

Carlos is sure his colleague dislikes him. He remembers her short replies and the meeting where she disagreed with him.

The first read

He has several clear memories of her being cold, so the pattern seems obvious and he starts avoiding her.

With this idea

He asks what he would expect to see if he were wrong, and remembers her recommending him for a project and laughing at his joke last week — which he had filed away. He decides she is simply brisk, and asks her for coffee.

What changed

He looked for evidence against his belief instead of only collecting evidence for it.

Easy to get wrong

• Believing that knowing about biases makes you immune. Everyone, including experts, still falls for them.
• Using bias labels to dismiss other people’s views while ignoring your own.

What this rests on

Well studied. Researchers have studied this a good deal. The core idea holds up, though details vary between people and settings.

• Amos Tversky & Daniel Kahneman — Judgment under Uncertainty: Heuristics and Biases (1974) — The paper that described anchoring, availability and representativeness: mental shortcuts that usually help and sometimes mislead.
• Daniel Kahneman — Thinking, Fast and Slow (2011) — A tour of decades of research on fast, intuitive judgement and slower, deliberate reasoning, and the predictable errors each can make. A few studies the book describes (notably on priming) have not replicated well; Kahneman himself later said so.

Try it: Three questions

1. Pick one belief you hold firmly about a situation in your life.
2. Ask: what would I expect to see if I were wrong — and have I looked?
3. If a number is involved, ask where it first came from.
4. Ask whether your examples are common or just memorable.

Reflect

• What belief of yours have you never tried to prove wrong?
• What first number or idea is anchoring a decision you are making?

Use it in the coming days

Before a decision this week that involves a number — a price, a salary, a time estimate — write down where the first number came from and one other reference point.

Where to do it: My Journal

Writing your reasoning down makes these traps easier to spot afterwards.