Anchoring is a cognitive bias where the first piece of information you encounter disproportionately influences your subsequent judgments and decisions. If someone asks you whether the population of Turkey is more or less than 35 million, then asks you to estimate the actual number, your answer will skew closer to 35 million than if the initial figure had been 100 million. That initial number acts as an “anchor,” pulling your thinking toward it even when it has no logical relevance to the question.
How Anchoring Works
Anchoring was first described by psychologists Amos Tversky and Daniel Kahneman in 1974 as one of several mental shortcuts (heuristics) people use when making decisions under uncertainty. The core mechanism is straightforward: when you need to estimate something unfamiliar, your brain latches onto available information as a starting point and then adjusts from there. The problem is that this adjustment is almost always insufficient. You stay too close to the anchor.
This happens even when the anchor is completely arbitrary. In one classic experiment, participants spun a rigged wheel that landed on either 10 or 65, then were asked what percentage of African countries belong to the United Nations. People who saw 10 on the wheel estimated around 25%. People who saw 65 estimated around 45%. A random number from a spinning wheel had no connection to geopolitics, yet it shifted answers by roughly 20 percentage points.
Two main psychological mechanisms explain why this happens. The first is “anchoring and adjustment,” where you consciously use the anchor as a starting point and try to move away from it, but stop adjusting too soon. The second is “selective accessibility,” where the anchor primes you to think of information consistent with it. If someone suggests a house is worth $400,000, your brain automatically starts retrieving reasons that price might be reasonable, making it harder to arrive at a dramatically different figure.
Anchoring in Everyday Decisions
Anchoring affects nearly every domain where numbers or expectations come into play. In salary negotiations, the first number put on the table sets the range for the entire conversation. Research consistently shows that whoever makes the first offer gains a significant advantage because the counteroffer tends to stay anchored near that initial figure. A candidate who opens at $90,000 will typically land a higher final salary than one who lets the employer open at $65,000, even if both candidates have identical qualifications.
Retail pricing relies heavily on anchoring. When a store displays a “was $200, now $120” tag, the $200 figure anchors your perception of the item’s value. You evaluate the $120 price not on its own merits but relative to that higher number, making it feel like a deal. This is why listing an original price alongside a sale price consistently increases purchases compared to simply showing the discounted price alone.
Real estate provides another well-studied example. When researchers gave real estate agents identical information about a property but varied the listing price, the agents’ appraisals tracked closely with whatever listing price they were shown. Agents who saw a higher listing price appraised the property higher, and those who saw a lower listing price appraised it lower. Most of the agents denied being influenced by the listing price, insisting they relied on their professional expertise. They were wrong.
Courts are not immune either. Studies have found that sentencing recommendations from prosecutors anchor judges’ decisions. When a prosecutor requests a longer sentence, judges tend to hand down longer sentences, and vice versa. In one striking experiment, even rolling dice before making a sentencing decision influenced the length of sentence that experienced judges chose.
Why Expertise Doesn’t Protect You
One of the most counterintuitive findings about anchoring is that knowledge and experience provide surprisingly little protection against it. The real estate agents in the study mentioned above were seasoned professionals, not students guessing at property values. Doctors estimating the probability of diseases, financial analysts projecting stock prices, and lawyers assessing case outcomes all show anchoring effects in controlled studies.
Experts do tend to show slightly smaller anchoring effects than novices in their area of expertise, but the bias doesn’t disappear. Part of the reason is that anchoring operates partly outside conscious awareness. You can’t easily override a process you don’t realize is happening. Even when participants in experiments are explicitly warned about anchoring and told to avoid it, the effect persists. Being told “don’t let this number influence you” reduces the bias only marginally.
Factors That Strengthen or Weaken Anchors
Not all anchors are equally powerful. Several factors determine how much pull an anchor exerts on your judgment.
- Uncertainty: The less you know about the true answer, the more you rely on the anchor. If someone asks you the boiling point of water, no anchor will shift your answer from 100°C. But if they ask about the boiling point of ethanol, you’re far more susceptible.
- Relevance: Anchors that seem related to the question at hand exert stronger effects than obviously random ones. A suggested price for a car pulls harder than a number from a license plate, though even irrelevant anchors have measurable effects.
- Mood: People in sad moods tend to show stronger anchoring effects than people in happy moods. One explanation is that sadness promotes more systematic, detail-focused processing, which paradoxically makes people more likely to engage deeply with the anchor rather than dismiss it.
- Extremity: Anchors that are more extreme don’t necessarily lose their power. Even clearly implausible anchors (like asking whether Mahatma Gandhi died before or after age 140) still shift estimates upward compared to more reasonable anchors on the low end.
Anchoring vs. Other Cognitive Biases
Anchoring is related to but distinct from several other biases. The framing effect describes how the way information is presented changes decisions, but framing involves the structure of choices rather than a specific numerical reference point. Confirmation bias involves seeking information that supports existing beliefs, which overlaps with anchoring’s selective accessibility mechanism but operates more broadly across all kinds of reasoning, not just numerical estimates.
Anchoring also differs from the status quo bias, where people prefer things to stay the same. With anchoring, you don’t necessarily prefer the anchor. You may actively try to move away from it and still fail to move far enough.
Reducing the Anchoring Effect
Completely eliminating anchoring from your thinking is probably impossible, but you can reduce its influence. The most effective strategy is to deliberately consider the opposite direction. If you’ve been given a high anchor, force yourself to think of reasons the true value might be very low. This “consider the opposite” technique has shown consistent results in reducing (though not eliminating) anchoring effects across multiple studies.
Another approach is to generate your own anchor before encountering someone else’s. If you’re negotiating a salary, research the market rate independently before the employer names a number. If you’re buying a house, form your own valuation before seeing the listing price. Your own well-researched anchor can compete with the one being presented to you.
Increasing your knowledge about the specific domain also helps at the margins. While expertise doesn’t make you immune, having concrete reference points reduces ambiguity, and less ambiguity means less room for an external anchor to operate. A mechanic who knows exactly what a brake job costs will be less anchored by an inflated quote than someone with no baseline understanding.
Perhaps the most practical takeaway is simply awareness of the situations where anchoring is most likely to affect you: negotiations, purchases, estimates of unfamiliar quantities, and any context where someone else presents a number before you’ve formed your own judgment. Recognizing those moments won’t neutralize the bias, but it creates a window where you can pause and apply deliberate counterstrategies rather than letting the first number you hear quietly shape everything that follows.