July 16, 2026 • 9 min read

Anchoring Bias: How the First Number You See Controls Your Decisions

Ask someone to estimate the population of Turkey after first asking whether it's more or less than 5 million, and you'll get a lower guess than if you'd first asked whether it's more or less than 80 million — even though the first number was completely arbitrary. That's anchoring, and it shapes far more of your daily decisions than feels comfortable to admit.

Anchoring bias is the tendency to rely too heavily on the first piece of information offered — the "anchor" — when making decisions, even when that number has no logical connection to the correct answer. Once an anchor is set, every subsequent judgment gets pulled toward it, whether you're negotiating a salary, evaluating a price tag, or estimating how long a project will take.

The Original Experiment

Psychologists Amos Tversky and Daniel Kahneman demonstrated the effect in a now-famous 1974 study. Participants spun a wheel rigged to land on either 10 or 65, then were asked to estimate the percentage of African countries in the United Nations. Despite knowing the wheel's number was random, people who saw 65 gave much higher estimates than people who saw 10. A meaningless number, seen seconds earlier, dragged their reasoning toward it.

What makes this finding uncomfortable is that it doesn't require the anchor to be relevant, credible, or even remembered consciously. The mind uses whatever number is available as a starting point and adjusts from there — and the adjustment is almost always insufficient.

Where Anchoring Shows Up in Real Life

Once you know the pattern, it's visible everywhere transactions or estimates happen:

• Retail pricing: a "was $200, now $89" tag anchors you to $200, making $89 feel like a bargain regardless of the item's actual worth.
• Salary negotiation: whoever states a number first sets the range the rest of the conversation revolves around.
• Real estate: a home's listing price anchors buyer offers, even among experienced agents who insist they're pricing independently.
• Project estimates: the first duration mentioned in a planning meeting anchors every later estimate, regardless of the work's actual complexity.

"The first number on the table has a gravitational pull on everything that follows it." — a common summary of decades of anchoring research

Why the Anchor Doesn't Need to Be Relevant

One of the strangest findings in this research area is that anchors work even when people know they're arbitrary. In one study, participants were asked to write down the last two digits of their social security number before bidding on unrelated items — wine, chocolate, keyboards. People with higher two-digit numbers bid meaningfully higher, despite the digits having zero connection to the products' value. The brain treats any recently seen number as a reference point, not just relevant ones.

Anchoring and Self-Assessment

Anchoring doesn't just affect how you judge prices and estimates from others — it affects how you judge yourself. If your first performance review used a harsh comparison point, later feedback tends to get measured against that early anchor rather than assessed fresh. The same applies to fitness goals, financial targets, and personal timelines: the first number you set for yourself becomes a gravitational center that's hard to escape, for better or worse.

Five Ways to Counter Anchoring

Anchoring in Planning and Goal-Setting

Anchoring compounds with other estimation errors, particularly the tendency covered in our guide to the planning fallacy, where an initial optimistic timeline anchors every later revision even as evidence of delay accumulates. It also interacts with loss aversion in negotiations, where the framing of an anchor as a "loss" from the opening number makes concessions feel more painful than they logically should. Building better judgment means deliberately using tools from mental models for better decisions to generate independent estimates before an anchor has a chance to take hold.

The goal isn't to eliminate anchors entirely — that's not really possible. It's to notice when one has been set, ask whether it's actually relevant, and deliberately generate an independent estimate before letting the first number in the room do your thinking for you.

Key Takeaways