Anchoring Bias

Anchoring bias is the tendency to rely too heavily on the first piece of information you encounter, letting it dominate your thinking and distort your judgment, even when later information is more informative.

In job interviews or performance reviews, the first few minutes can create an anchor, leading a manager to ignore later evidence that contradicts their initial impression. This works in both directions — a bad early impression is just as sticky as a good one, and just as unreliable.

A doctor sees a patient, forms an immediate impression, and then spends the rest of the consultation finding evidence to support that first impression. Even when contradictory signs appear, even when the patient mentions symptoms that don’t fit, even when the obvious answer is sitting right there in front of them.

They can’t see it. They’re anchored to that first piece of information, and your brain does this constantly. Every decision you make is influenced by whatever anchor your brain latched onto first.

How Anchoring Controls Your Decisions

Here’s how it works. Someone shows you a house listed at £800,000. That number becomes your anchor. Even if the house is clearly overpriced, even if comparable properties in the area sell for £650,000, you’ll negotiate around that £800,000 anchor. You might get them down to £750,000 and feel like you won. You didn’t. You got anchored at a higher price.

Or you’re shopping for a laptop. The first one you see costs £1,500. Now every other laptop gets judged against that price. A £1,200 laptop looks like a bargain, even if it’s objectively overpriced for its specs. A £900 laptop feels cheap, possibly inferior, even if it’s perfectly adequate, it just feels too cheap.

Your brain uses that first number as a reference point for everything that follows. It’s automatic. You’re not consciously thinking, ‘I’ll use this as my baseline.’ Your brain does it without asking permission.

Research shows this effect is remarkably powerful. In a well-known study, participants were asked whether Gandhi was more or less than 140 years old when he died. Obviously absurd. Everyone knows he wasn’t 140. But when asked to estimate his actual age at death, those participants gave meaningfully higher estimates than people who were first asked whether he was more or less than 9 years old.

The anchor pulled their estimates toward it, even though they consciously knew it was ridiculous.

Why This Matters in Medicine

In medical practice, anchoring bias can contribute to genuinely serious mistakes.

A patient comes in. You form your first impression based on their appearance, their opening sentence, or something in their notes. That impression becomes your anchor. You start looking for evidence that confirms it. You unconsciously discount evidence that contradicts it.

The patient mentions chest pain. Your first thought is gastric reflux because they’re overweight and just ate a large meal. That’s your anchor. They mention the pain radiates to their jaw. You explain that away. They mention feeling clammy. You rationalise it. You’re so anchored to your initial gastric reflux diagnosis that you miss the myocardial infarction sitting right in front of you.

This happens. Not rarely. Regularly. Diagnostic error causes a large, and disputed, number of deaths every year — an older estimate put US hospital deaths in the tens of thousands annually, and more recent analysis suggests the true toll, including permanent disability, is considerably higher. Anchoring bias is one identifiable contributor to that error, though the best evidence suggests knowledge gaps and premature closure — settling on a diagnosis before genuinely testing it — do more of the damage than any single cognitive bias on its own.

Start Again

The solution? Start from scratch. Deliberately. Actively look for disconfirming evidence. Ask yourself ‘What am I missing?’ Force yourself to consider alternative diagnoses, even when you’re confident about your initial impression.

Especially when you’re confident about your initial impression.

Anchoring in Your Life

You’re not making life-or-death medical decisions, but anchoring bias is still costing you.

In negotiations, the person who sets the first number typically wins. They’ve established the anchor. If you’re selling your car and the buyer opens with ‘I’ll give you £3,000,’ that anchor will pull your counteroffer downward. Even if you were planning to ask £5,000, you’ll probably come down to £4,500 or £4,000. The anchor worked.

Smart negotiators know this. They make the first offer. They set the anchor high if they’re selling, low if they’re buying. They control the frame of the entire negotiation with that first number.

In relationships, your first impression of someone becomes incredibly sticky. If your initial take is ‘This person is arrogant,’ you’ll interpret everything they do through that lens. Confidence becomes arrogance. Self-assurance becomes ego. You’re anchored, and you’ll filter all subsequent interactions through that anchor.

Even when they demonstrate humility, even when they show genuine kindness, you’ll find ways to explain it away. ‘They’re just putting on an act.’ ‘They want something.’ Your anchor won’t let go.

Why Anchoring Is So Persistent

Anchoring bias persists because of how your brain processes information. You’re not a perfectly rational computer evaluating each piece of data independently. You’re a pattern-matching machine looking for shortcuts, and that’s exactly what makes you vulnerable to anchoring.

When you encounter new information, your brain doesn’t start from zero. It starts from the anchor and adjusts from there. But here’s the problem. Those adjustments are usually insufficient. You don’t adjust far enough away from the anchor to reach the objectively correct answer.

If someone tells you a house costs £800,000, and you discover comparable houses sell for £650,000, you should adjust your valuation to £650,000. You don’t. You adjust to maybe £700,000 or £720,000. Still influenced by that initial anchor.

This happens even when you know about anchoring bias. Even when you’re consciously trying to avoid it, it still affects you.

Research demonstrates that experts aren’t immune. Professional real estate agents who view the same properties at different listing prices give different valuations based on the listing price — and, tellingly, deny that the listing price influenced them at all. They know about anchoring bias. They’re trained to avoid it. It affects them anyway.

Breaking Free from Anchors

You can’t eliminate anchoring bias. It’s built into how your brain works. But you can reduce its impact.

First, actively seek disconfirming information. Don’t just look for evidence that supports your initial impression. Deliberately look for evidence that contradicts it. Ask ‘What would I need to see to change my mind about this?’

Second, start from scratch periodically. In medical practice, we call this ‘going back to square one.’ Forget your initial diagnosis. Look at the patient fresh. Consider the symptoms without your preconceptions. What diagnosis would fit if you’d never seen this patient before?

Third, notice the anchor, even though noticing it on its own won’t make it disappear. Recognise when someone has set one. In negotiations, if they make the first offer, you’ve been anchored. Naming it — ‘that’s their anchor, it’s not reality’ — won’t dissolve its pull, but it tells you when to actually run the two steps above.

Fourth, get outside perspectives. Other people aren’t anchored to your anchor. They’ll see things you’re missing. In medicine, we have protocols for this. Second opinions. Peer review. Multidisciplinary team meetings. These exist specifically to catch anchoring errors.

Apply this to your life. Making a big decision? Ask someone uninvolved. They haven’t been anchored by your initial thinking. They’ll spot things you’ve been filtering out.

The Cost of Staying Anchored

When you let anchors control your decisions, you pay in missed opportunities, poor judgments, and persistent errors.

You overpay for purchases because the seller has set a high anchor price. You undersell your services because you anchored too low. You maintain relationships with the wrong people because your first impression was positive, and you can’t update it. You avoid good opportunities because your initial assessment was negative and you filtered out contradictory evidence.

In medicine, you misdiagnose patients. In business, you misjudge markets. In life, you miss what’s actually happening because you’re too fixated on what you first thought was happening.

The anchor feels like the truth. That’s the danger. You’re not consciously thinking, ‘I’m being irrational.’ You’re thinking, ‘This is obviously correct.’ Your confidence in your anchored judgment prevents you from questioning it.

Here’s what you need to remember. The first piece of information you encounter isn’t necessarily the most accurate. It’s just the first. Your brain gives it disproportionate weight because that’s what brains do. But you can override this.

Question your first impressions. Look for disconfirming evidence. Start from scratch when it matters. Get outside perspectives.

And when someone makes the first offer in a negotiation, recognise they’re setting an anchor. Don’t let it pull you where you don’t want to go.

The anchor only has power if you don’t see it. Once you recognise it’s there, you can work around it.

Being Anchored in Your Old Self

One more thing: you’ve come a long way. You’ve changed. You are not your old self any more, so don’t devalue yourself, and don’t let others do it to you either.

When people tell you something is really difficult, they may be inflating the difficulty, which can make it feel too difficult for you to achieve, making it easier for you to give up. If they tell you that something isn’t important, they may be devaluing the effort and work you’ve already put in. Don’t accept either framing without checking it against the evidence.

Be aware of what you want and what value it will give you, and don’t let others anchor your mind to alternatives.

Anchoring bias is one way your past experience can work against you. The Curse of Knowledge is another, and in some ways more dangerous, because the better you get at something, the harder it becomes to see it the way a beginner does. The next article unpacks why that matters.

Further reading

1. Tversky, A., & Kahneman, D. (1974). Judgment under uncertainty: Heuristics and biases. Science, 185(4157), 1124–1131.
2. Northcraft, G. B., & Neale, M. A. (1987). Experts, amateurs, and real estate: An anchoring-and-adjustment perspective on property pricing decisions. Organizational Behavior and Human Decision Processes, 39(1), 84–97.
3. Epley, N., & Gilovich, T. (2006). The anchoring-and-adjustment heuristic: Why the adjustments are insufficient. Psychological Science, 17(4), 311–318.
4. Wilson, T. D., Houston, C. E., Etling, K. M., & Brekke, N. (1996). A new look at anchoring effects: Basic anchoring and its antecedents. Journal of Experimental Psychology: General, 125(4), 387–402.
5. Norman, G. R., Monteiro, S. D., Sherbino, J., Ilgen, J. S., Schmidt, H. G., & Mamede, S. (2017). The causes of errors in clinical reasoning: Cognitive biases, knowledge deficits, and dual process thinking. Academic Medicine, 92(1), 23–30.