Anchoring Bias
Edited by Paweł Raja, PhD · Published · Updated
Definition
Anchoring Bias is the disproportionate reliance on the first piece of information encountered (the 'anchor') when making subsequent judgments or estimations.
Why it happens: the psychology of anchoring bias
Tversky and Kahneman (1974) showed anchoring with a rigged wheel of fortune that stopped at 10 or 65. Participants then estimated the percentage of African countries in the United Nations. Those who saw 10 gave a median estimate of 25%; those who saw 65 gave 45%. The anchor was obviously random and still moved the answers.
Two mechanisms are well supported. Insufficient adjustment: people start from the anchor and adjust away from it, but stop too early (Epley & Gilovich, 2006). Selective accessibility: considering whether the answer could be near the anchor brings anchor-consistent information to mind (Strack & Mussweiler, 1997). Which one dominates depends on whether people generate the anchor themselves or are given it.
Expertise offers little protection. Real-estate agents' appraisals followed the listing price they were shown (Northcraft & Neale, 1987). Experienced judges' sentencing decisions were pulled by a number rolled on dice (Englich, Mussweiler & Strack, 2006).
Anchoring is also one of the most replicable effects in psychology. In the Many Labs 1 project, run in 36 labs, the anchoring effects replicated strongly, unlike several other well-known findings.
Anchoring Bias examples
In a field experiment, professional real-estate agents who toured the same house appraised it higher when they were shown a higher listing price — while insisting the listing price had not influenced them.
- In a salary negotiation, the first figure named tends to pull the final agreement toward it.
- 'Was $200, now $120' pricing anchors shoppers to the higher number so the discount feels larger than it is.
How to design for it (nudge strategy)
Set high but realistic starting values or suggested donation tiers (e.g., '$50, $100, $250' rather than '$10, $20, $50') to anchor the user's scale.
Ethical use: design for choices people would endorse on reflection — a nudge, not sludge. Be transparent and keep opting out easy.
Key studies
A random wheel-of-fortune number shifted estimates of African UN membership (medians 25% vs. 45%).
Tversky, A., & Kahneman, D. (1974). Judgment under uncertainty: Heuristics and biases. Science, 185(4157), 1124–1131. DOI →
Agents' appraisals of the same house followed the listing price they were given.
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. DOI →
The last two digits of participants' social security numbers anchored how much they would pay for everyday products.
Ariely, D., Loewenstein, G., & Prelec, D. (2003). "Coherent arbitrariness": Stable demand curves without stable preferences. Quarterly Journal of Economics, 118(1), 73–105. DOI →
Experienced judges' sentences were influenced by a number they had just rolled on dice.
Englich, B., Mussweiler, T., & Strack, F. (2006). Playing dice with criminal sentences: The influence of irrelevant anchors on experts' judicial decision making. Personality and Social Psychology Bulletin, 32(2), 188–200. DOI →
Anchoring effects replicated robustly across 36 samples.
Klein, R. A., et al. (2014). Investigating variation in replicability: A "Many Labs" replication project. Social Psychology, 45(3), 142–152. DOI →
Related biases
Anchoring Bias: frequently asked questions
What is anchoring bias?
Anchoring bias is relying too heavily on the first piece of information you encounter — the anchor — when making an estimate or decision, even when that anchor is irrelevant.
What is an example of anchoring bias?
A 'was $200, now $120' price tag makes $120 feel like a bargain; the first salary figure named in a negotiation pulls the final offer toward it; a high listing price raises what buyers and even agents think a house is worth.
Why does anchoring happen?
People adjust away from a starting value but stop too soon, and thinking about the anchor makes anchor-consistent information easier to recall. Both push estimates toward the anchor.
How can you avoid anchoring bias?
Form your own estimate before seeing any numbers, deliberately consider reasons the anchor might be wrong, and use independent reference points such as comparable prices or base rates.
Cite this page
Behavioral Economics Lab. "Anchoring Bias – Definition, Examples & Evidence." Behavioral Economics Lab, https://www.behavioraleconomicslab.com/biases/anchoring.