Show someone a random number, then ask an unrelated question, and their answer drifts toward that number — even when they know it was random. That is anchoring bias: the first figure you encounter quietly sets the frame for every judgment that follows. It runs your shopping, your salary, and negotiations you do not realise you are in.
In this article:
- Why the first number wins
- Does anchoring actually replicate?
- Why your correction is always too small
- Where anchoring shows up
- Anchoring in a negotiation
- Defending against it
- Why knowing about it is not enough
- FAQ
Why the First Number Wins
In the study that named the effect, Amos Tversky and Daniel Kahneman spun a rigged wheel that landed on 10 or 65, then asked people what percentage of African nations were in the UN. Those who saw 10 guessed about 25%; those who saw 65 guessed about 45%. Participants watched the wheel spin. They knew it was random. It moved their answers anyway.
The American Psychological Association defines anchoring as exactly this: relying too heavily on the first piece of information when making a decision. Your mind treats the anchor as a starting point and adjusts from it — but the adjustment almost always stops short.
Does Anchoring Actually Replicate?
This question matters more than it used to. A great deal of classic social psychology from this era has failed to reproduce, and a reader is right to ask whether anchoring is another casualty.
It is not. Anchoring is one of the better-replicated effects in the field. The Many Labs replication project tested it across many independent samples and recovered it consistently.
One honest caveat: well-powered replications suggest the direction of the effect is solid while the size reported by early, smaller studies was often inflated. So treat anchoring as real and reliable, and treat any specific headline percentage with more caution than the effect itself.
Why Your Correction Is Always Too Small
The useful mental picture is not “the anchor tricks you.” It is that the anchor becomes your starting point, and you stop adjusting as soon as the number stops feeling obviously wrong — which happens well before you reach an accurate figure.
That is why anchoring survives awareness. You can know a price is designed to anchor you and still end up negotiating within the range it established, because the range itself is what you inherited.
Where Anchoring Shows Up
- Pricing. “Was €299, now €149” makes €149 feel cheap. The crossed-out price is the product, not the discount.
- Salary. Whoever names a number first sets the range the whole conversation orbits.
- Menus. One very expensive dish makes everything under it look reasonable.
- Estimates. A colleague’s “this will take two days” anchors your own guess before you have thought about the work.
- Medicine and law. An initial diagnosis or an opening damages figure both function as anchors for everything assessed afterwards.
It is one of the most exploited cognitive biases that control daily life, and a staple of the manipulation tactics used every day in shops and sales calls.
Anchoring in a Negotiation
The practical question people actually have is whether to open first.
If you have a reasonable sense of the range, opening first is usually an advantage, because you set the anchor rather than inherit one. If you genuinely do not know the range — an unfamiliar market, a role you have never held — opening first risks anchoring yourself low, and letting the other side speak buys you information.
Either way, the move that helps most is done before the conversation starts: decide your own number in advance, in writing. An anchor lands hardest on someone who has not got one.
Defending Against It
- Set your own anchor first. Before you see a price or hear an offer, decide what the thing is worth to you. Then their number lands against yours instead of into a vacuum.
- Name the anchor out loud. “That €299 is doing psychology, not accounting.” Labelling it does not remove it, but it converts an invisible frame into a visible claim you can argue with.
- Deliberately overcorrect. Because adjustment from an anchor is reliably too small — a documented feature of this cognitive bias — move further than feels right, then check.
- Get an outside number. A comparable price, a salary band, a second estimate. Any independent figure breaks the monopoly the first one had. The same principle runs through the psychology behind everyday decisions.
Why Knowing About It Is Not Enough
Anchoring persists when people are warned about it in advance, and it persists when the anchor is transparently arbitrary. That is the uncomfortable part, and it is the same pattern that shows up across the most common cognitive biases: awareness is a weak intervention, and procedure is a strong one.
Which means the defence that works is not “remember that anchoring exists.” It is having your own number written down before the other one appears.
FAQ
Does anchoring work even if I know about it?
Largely yes. It persists when people are warned and when the anchor is obviously random. Knowing helps only if it makes you set your own reference point first.
What is the best defence against anchoring in a negotiation?
Prepare your number in advance and write it down. Then anchor first if you know the range, and let them open if you do not.
Is anchoring bias the same as the anchoring effect?
They are used interchangeably. “Effect” describes the finding; “bias” emphasises that the result is a systematic error rather than a neutral influence.
Has the anchoring effect survived the replication crisis?
Yes, better than most findings of its generation. Large multi-laboratory replications recover it reliably. The direction is robust; individual effect sizes from early studies were often overstated.
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