Thinking, Fast and Slow · Daniel Kahneman

The first number you hear quietly drags every guess after it

Curated by · reviewed 2026-05-31

The first number you see becomes a mental reference point, and your later estimates drift toward it — even when that anchor is arbitrary or completely irrelevant.

Anchoring: the first number you see becomes a reference point that pulls all your later estimates toward it — even when it's irrelevant.

Spin a wheel that lands on 65, then ask people what percentage of African nations are in the UN — they guess higher than people who watched the wheel land on 10. The wheel is random and everyone knows it. Yet the number they just saw still drags their answer.

Daniel Kahneman and Amos Tversky called this anchoring: the first value you encounter sets a reference point, and your mind adjusts from there — usually not far enough. It's why a slashed "was €200, now €80" price feels like a steal, and why the first offer in a negotiation shapes the entire range that follows.

Before you let a number land, ask: "Where did this anchor come from, and would my estimate be different without it?" Set your own reference point first — your honest target, your independent valuation — before you hear theirs. The first number isn't the true one; it's just the first.

Why it matters

It explains why prices, offers, and first impressions hold so much power — and gives you a way to think past the number in front of you.

A common misreading

Misread as "first impressions matter." Anchoring is stranger: even a clearly irrelevant or random number pulls your estimate toward it, often without your awareness. That's why it's exploited in pricing and negotiation. Defending against it means generating your own number before you hear theirs.

Put it to work

Test yourself

Why does a random first number change people's later estimates?
Show answer
Anchoring: the first number sets a reference point your mind adjusts from — and the adjustment is usually too small, so your estimate drifts toward the anchor.

Reading it once isn’t remembering it.

Lock this idea into memory with a 5-minute active-recall session — the science of spaced repetition, no signup.

Try this idea free →
Worth remembering? Post on X
Embed this idea on your site

A self-contained card that links back here — paste it anywhere:

Related ideas

Losses hurt about twice as much as gains feel goodThinking, Fast and Slow We're irrational — but in predictable waysPredictably Irrational Your mind runs on two systems: fast and slowThinking, Fast and Slow

FAQ

What is the anchoring effect?
Anchoring is the tendency to rely too heavily on the first piece of information — often a number — when making decisions. Later estimates drift toward that anchor, even when it's arbitrary or irrelevant.
How does anchoring affect prices and negotiation?
A high "original" price anchors what you think an item is worth, making a discount feel like a bargain. In negotiation, the first offer sets the reference range both sides adjust from, so it carries outsized weight.