Anchoring & Adjustment

Spin a wheel of fortune, watch it stop on a number, then answer a question that has nothing to do with the wheel: what percentage of the countries in the United Nations are in Africa? In 1974, two psychologists ran exactly this, and the wheel was rigged to land on either 10 or 65. People who saw 10 guessed, on average, about 25%. People who saw 65 guessed about 45%. Same question, same true answer, same room — and a casino wheel everyone had just watched being spun moved the average estimate by twenty full points. The number was transparently random. It changed the answer anyway.

That is anchoring: the first number you encounter becomes a mental starting point — an anchor — and your final estimate stays stubbornly close to it, even when the anchor is arbitrary, irrelevant, or obviously planted. The two psychologists were Amos Tversky and Daniel Kahneman, the same pair who mapped the availability heuristic and, later, prospect theory; anchoring is one of the three biases in their founding 1974 paper and among the most replicated findings in all of psychology. It works on experts and novices, on people warned about it in advance, on estimates of population and price and probability and prison sentences. It barely weakens when you offer money for accuracy. It is, frankly, a little humiliating — which is exactly why it’s worth learning to see.

The mechanism has a second half, and it’s where the name comes from. You don’t ignore the anchor and you don’t stay on it either — you adjust away from it, toward what you actually believe. The catch is that you stop too early. You adjust until your estimate enters the range of “plausible,” then quit, and that range is wide, so you halt while still closer to the anchor than to the truth. Psychologists call this insufficient adjustment, and it’s the engine of the whole effect: not that people can’t move off the anchor, but that they don’t move far enough. Two people handed two different anchors both adjust inward, both stop short, and end up far apart — a gap manufactured entirely out of two meaningless numbers.

This course follows that mechanism everywhere it does damage. You’ll pin down the precise definition and watch the wheel-of-fortune experiment (and the equally absurd one where your own Social Security number changes what you’ll pay for wine). You’ll open up why anchors stick — the two competing accounts, anchor-and-adjust and selective accessibility, and why even a number you know is random still pulls. You’ll tour where it bites in the real world: the first offer in a negotiation, the “was $1,200, now $499” price tag, the asking price on a house that moves what professional appraisers decide it’s worth, the prosecutor’s demand that shifts a judge’s sentence — even when the “demand” was set by rolling dice. And because a bias you can’t defend against is just a nicer name for a weakness, you’ll finish with the debiasing craft: consider the opposite, generate your own anchor before you hear theirs, question whether the anchor has any business being relevant, and think in ranges instead of single numbers.

It builds on two ideas already in hand: thinking in probabilities (so you can see anchoring as a distortion of the estimates and odds you’re trying to judge) and incentives (because the first number is the cheapest lever there is — a salesperson, negotiator, or headline sets your anchor for free, changing your behavior without changing a single real payoff). By the end you won’t just know that the first number matters. You’ll catch it in the act — in every price tag, opening bid, salary band, and “expert estimate” someone puts in front of you — and you’ll know how to set the anchor instead of being set by it.