What Is Anchoring Bias? | Definition & Examples

Anchoring bias describes people’s tendency to rely too heavily on the first piece of information they receive on a topic. Regardless of the accuracy of that information, people use it as a reference point, or anchor, to make subsequent judgements. Because of this, anchoring bias can lead to poor decisions in various contexts, such as salary negotiations, medical diagnoses, and purchases.

Example: Anchoring bias 
You are considering buying a used car, and you visit a car dealership. The dealer walks you around, showing you all the higher-priced cars, and you start worrying that you can’t afford a car after all.

Next, the car dealer walks you toward the back of the lot, where you see more affordable cars. Having seen all the expensive options, you think these cars seem like a good bargain. In reality, all the cars are overpriced. By showing you all the expensive cars first, the dealer has set an anchor, influencing your perception of the value of a used car.

What is anchoring bias?

Anchoring bias (also known as anchoring heuristic or anchoring effect) is a type of cognitive bias that causes people to favour information they received early in the decision-making process. People hold on to this information, called an anchor, as a reference point and fail to correctly adjust their initial impressions, even after receiving additional information.

Anchoring bias

Once the anchor is set, subsequent judgements are made by adjusting away from that anchor, while staying within the range set by it. For example, the initial price offered for a used car sets the standard for the rest of the negotiation. Here, prices lower than the initial price seem like a good deal, even if they are still higher than the car’s actual value. As a result, our perception of reality is distorted, and our decisions are biased.

Depending on their sources, anchors can be external or internal.

  • External anchors are reference points provided by others (for example, the suggested retail price tags we see on many products).
  • Internal anchors are reference points based on beliefs, experiences, or contextual clues. For example, if your parents followed an active lifestyle and exercised a lot, this experience might set a standard level of exercise for you in adulthood.
It is important to keep in mind that the more knowledgeable we are about a certain topic, the less likely we are to fall for anchoring bias. When we don’t have enough information to know how to value something, we are more likely to be influenced by anchors.

Why does anchoring bias happen?

Although there is no consensus as to why anchoring bias happens, two mechanisms can help explain this phenomenon:

  • Anchoring and adjustment applies best to situations where people are influenced by an internal anchor.
  • Confirmatory hypothesis testing can explain how external anchors influence our judgement.

Anchoring and adjustment

Anchoring and adjustment is the mechanism that explains how people try to answer a general knowledge question when they don’t know the answer.

  • If people don’t know the correct answer, they try to make an educated guess and adjust from there until they reach a conclusion that seems plausible.
  • This initial estimation becomes an internal anchor and influences subsequent adjustments.
  • Because the adjustment is usually insufficient, it results in a biased estimation. In other words, people always end up with an answer that is close to the anchor anyway.
Example: Anchoring and adjustment
Suppose you need to answer the question ‘How long does it take Mars to orbit the Sun?’ but don’t know the correct answer and you’re not allowed to search for it online! You remember that Mars is between Earth and Jupiter, and that it takes 12 years for Jupiter to orbit the Sun.

Based on this, you estimate that the correct answer is somewhere close to 12 years. After thinking some more, you come up with your final answer: 6 years. Unfortunately, your internal anchor (12 years) was too high, and it didn’t allow you to adjust sufficiently so as to approximate the correct answer, which is actually 1.88 years.

Confirmatory hypothesis testing

When we are presented with an external anchor, our first response is to consider the anchor as a possible answer. While we are doing that, we activate existing information in our brain that is consistent with the anchor.

  • This information is more accessible, and so we use it for estimating the absolute value, a phenomenon called selective accessibility.
  • In general, after a comparison with a high anchor, people are likely to base their absolute estimate on knowledge indicating that the target object or situation value is fairly high.
  • However, after a comparison with a low anchor, people are likely to base their absolute estimate on knowledge suggesting that the value is fairly low.
Example: Selective accessibility 
When asked whether Mahatma Gandhi was younger or older than 86 when he died, people often engage in confirmatory hypothesis testing. In other words, they are influenced by the phrasing of the question and recall information that supports the hypothesis presented to them: that Gandhi was approximately 86 years old when he died. As a result, this information is likely to influence their final answer.

This selective accessibility mechanism works even when anchors are clearly unrealistic. When asked whether Mahatma Gandhi was

  1. older or younger than 140 years old when he died


  1. older or younger than 9 years old when he died

participants were influenced by these implausible anchors.

Participants who received the high implausible anchor estimated on average that Gandhi lived 67 years, whereas participants who received the low implausible anchor thought that he was just 50 years old when he died.

Anchoring bias examples

Salary negotiations are particularly susceptible to anchoring bias. The person who opens the negotiations and sets the anchor has an advantage.

Example: Anchoring bias and salary negotiations 
You have passed the first round of interviews for a job, and you are now invited to a second round. During a call, the HR person makes you an offer of $50,000 per year. Considering the role and your previous experience, you know this is too low of an offer.

With that amount as a starting point, you manage to negotiate up to $55,000. You are satisfied that you got more than they initially offered. In reality, the HR person could have offered you more, but they used the anchoring effect against you. By starting with a low value, they influenced your perception of what an acceptable salary would be.

Anchors that are entirely arbitrary and unrelated to the decision can still influence our judgement, especially when we lack the knowledge to make an educated guess.

Example: Anchoring bias and random anchors
In an experiment, participants were asked to estimate the percentage of African countries in the United Nations (UN) in two ways:

  • First, they were asked whether the percentage is smaller or larger than a given number (the anchor), which was randomly determined by spinning a wheel.
  • Next, participants were asked to estimate the exact percentage of African UN member states.

Even though the anchor was entirely arbitrary and irrelevant to the question, it still influenced participants who used it as a standard in their subsequent judgement. As a result, their answers were close to the anchor. For example:

  • If the anchor was 10, participants’ mean estimate of the true value was 25.
  • If the anchor was 65, their mean estimate was 45.

This shows that under the anchoring bias, irrelevant anchors are just as impactful as anchors that offer relevant informational cues.

Other types of cognitive bias in decision-making

Apart from anchoring bias, there are two more types of heuristics that people use that can affect their decision-making:

  • The availability heuristic occurs when we place greater emphasis on information that is easier to recall while forming a judgement.
  • The representativeness heuristic arises when we estimate the probability of something based on the degree to which it is similar to (or is representative of) a known situation.

Although all of them help us reduce the time and effort needed to form a judgement, they do so in different ways.

Other types of research bias

Frequently asked questions

What is the difference between anchoring bias and availability bias?

Although anchoring bias and availability bias are both types of cognitive bias (or heuristics) and may seem similar, they are quite different:

  • The availability bias refers to people’s tendency to estimate the probability of an outcome (e.g., being struck by lightning), based on how easily they can recall similar events. Because of this, people sometimes mix up ease of recall with probability or frequency and end up believing that some events are far more common than they actually are.
  • Anchoring bias refers to people’s tendency to give disproportionate weight to the first piece of information they receive in a decision-making context. As a result, this becomes a reference point or anchor that influences people’s perception of subsequent information.

In other words, although both anchoring and availability bias influence our perception, anchoring is related to the order in which we receive the information, while availability is related to ease of recall.

When does anchoring bias occur?

Anchoring bias occurs when you focus on the first piece of information you receive during a decision-making process and fail to consider any other information that follows.

What is anchoring and adjustment bias?

Anchoring and adjustment bias refers to the mechanism underlying cases in which we are influenced by an internal anchor or reference point. When we are faced with a decision or question and we are uncertain about the right option, we try to make an educated guess.

For example, when we are trying to estimate how long it will take us to write a paper. In this case, we start with an initial anchor value that seems reasonable and then adjust until an acceptable answer is found. Because we subconsciously place more importance on the initial value or answer we come up with, we typically fail to adjust sufficiently from there on and our judgement is biased.

Sources for this article

We strongly encourage students to use sources in their work. You can cite our article (APA Style) or take a deep dive into the articles below.

This Scribbr article

Nikolopoulou, K. (2023, June 02). What Is Anchoring Bias? | Definition & Examples. Scribbr. Retrieved 17 July 2024, from https://www.scribbr.co.uk/bias-in-research/the-anchoring-bias/


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Kassiani Nikolopoulou

Kassiani has an academic background in Communication, Bioeconomy and Circular Economy. As a former journalist she enjoys turning complex scientific information into easily accessible articles to help students. She specialises in writing about research methods and research bias.