Within Search Bias
Why Searching Can Make Beliefs More Stubborn
The narrow search effect explains why people can search sincerely and still end up less exposed to evidence that would change their minds.
On this page
- How prior beliefs shape search terms
- Why narrow results reduce belief updating
- Where the effect appears beyond politics
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Introduction
The narrow search effect explains why people can search sincerely for evidence yet become less, rather than more, likely to change their minds. The key insight is that belief reinforcement often begins before any search results appear. Existing beliefs influence the words people type into a search engine or AI assistant, and those words determine which evidence is retrieved. When queries are narrowly framed, even high-quality search systems tend to return information that fits the question being asked, limiting exposure to genuinely conflicting evidence. This means that online confirmation bias is not only about choosing partisan websites or ignoring inconvenient facts; it can originate in the search query itself. Recent research suggests this pattern is remarkably consistent across subjects ranging from health and finance to energy policy and crime, and across both conventional search engines and AI-assisted search tools. [PubMed]pubmed.ncbi.nlm.nih.govThe narrow search effect and how broadening…by E Leung · 2025 · Cited by 11 — We demonstrate that the combination of users' prio…
How prior beliefs shape search terms
The narrow search effect begins with an apparently simple decision: how to phrase a question.
Suppose two people want to learn about the same issue. One searches for “benefits of nuclear power”, while another searches for “risks of nuclear power”. Both may believe they are conducting an objective investigation. Yet each query already directs the search system towards a particular subset of available information.
Researchers Eugina Leung and Oleg Urminsky demonstrated that people consistently generate search terms that align with their existing beliefs. Across 21 studies, including 14 preregistered experiments, participants with stronger prior opinions chose more directionally framed search queries. Those queries produced narrower sets of results, reducing subsequent belief updating. Importantly, this pattern appeared across numerous topics, including coronavirus, caffeine, food safety, Bitcoin, gas prices, crime rates and nuclear energy. It also appeared across multiple search platforms, including Google, ChatGPT, AI-powered Bing and custom experimental search interfaces. [PNAS]pnas.orgThe narrow search effect and how broadening…24 Mar 2025 — We demonstrate that the combination of users' prior beliefs influencing…
The researchers describe this as a chain rather than a single bias:
- prior beliefs influence query wording; [knowledge.uchicago.edu]knowledge.uchicago.eduUChicago KnowledgeThe narrow search effect and how broadening…by E Leung · 2025 · Cited by 11 — Studies 1 to 5 show that users' prior…
- query wording constrains retrieved information;
- constrained information limits opportunities for belief revision.
Because each step feels reasonable to the user, the overall process is often invisible.
Why narrow results reduce belief updating
The most important contribution of the narrow search effect is explaining why searching does not necessarily produce more accurate beliefs.
Search systems are generally designed to retrieve information relevant to the user’s request. If the request itself is one-sided, the system may perform exactly as intended while still exposing the user to an incomplete evidence base. The limitation therefore arises from the interaction between human psychology and search algorithms rather than from either component alone. [PNAS]pnas.orgThe narrow search effect and how broadening…24 Mar 2025 — We demonstrate that the combination of users' prior beliefs influencing…
The PNAS experiments found that narrower searches consistently produced smaller changes in participants’ beliefs after reviewing evidence. People were not necessarily rejecting contradictory information. Instead, they simply encountered less of it because their original search wording filtered much of it out before evaluation even began. [PNAS]pnas.orgThe narrow search effect and how broadening…24 Mar 2025 — We demonstrate that the combination of users' prior beliefs influencing…
This distinction matters because it shifts attention away from deliberate motivated reasoning towards an earlier stage of information gathering. Someone can honestly believe they are “checking the evidence” while unknowingly constructing a search that excludes much of the evidence capable of changing their view.
The evidence goes beyond political topics
Although discussions of online echo chambers often focus on politics, the narrow search effect appears in many everyday decisions.
The research intentionally examined diverse domains to test whether the mechanism depended on ideological conflict. Instead, similar patterns emerged across:
- health questions, such as disease risks and nutrition;
- financial topics, including cryptocurrency and prices;
- public policy issues such as crime and energy;
- general consumer beliefs about food and beverages.
This breadth suggests the effect reflects a general feature of human information seeking rather than a phenomenon unique to political identity. [UChicago Knowledge]knowledge.uchicago.eduUChicago KnowledgeThe narrow search effect and how broadening…by E Leung · 2025 · Cited by 11 — Studies 1 to 5 show that users' prior…
Earlier experimental work reached related conclusions through a different mechanism. Researchers found that confirmation bias becomes especially powerful when confirming and disconfirming evidence use different terminology. If contradictory evidence is described using different words from those already embedded in the search query, search engines may retrieve mainly confirming information even when relevant opposing evidence exists elsewhere. [CORE]core.ac.ukerbate confirmation bias by generating results that consist only of confirming evidence for search…Read more…
The consequence is that narrow searching can reinforce mistaken beliefs in many practical settings, including medical self-diagnosis, investment research and consumer decision-making.
Broadening search promotes more accurate belief updating
The same research also tested whether the effect could be reduced.
One approach involved encouraging broader, less directional search queries. Instead of asking questions that assumed a particular answer, users were prompted to formulate more neutral searches. Another approach altered search presentation so that results represented a wider range of relevant evidence.
Both strategies increased belief updating compared with standard narrow searches, with algorithm-based interventions generally producing larger improvements than relying solely on users to reformulate their own queries. Rather than forcing artificial balance, broader retrieval simply increased the likelihood that users encountered relevant evidence inconsistent with their starting assumptions. [PNAS]pnas.orgThe narrow search effect and how broadening…24 Mar 2025 — We demonstrate that the combination of users' prior beliefs influencing…
This finding is significant because it suggests that the narrow search effect is not inevitable. Small changes to either user behaviour or search-system design can substantially increase exposure to information capable of changing minds.
What this means for better analytical thinking
The narrow search effect changes how confirmation bias should be understood during online research.
Instead of asking only whether the sources are trustworthy, it is equally important to ask whether the initial search question unintentionally excluded important evidence. Good analytical thinking therefore begins before evaluating results.
Useful habits include:
- replacing “why is X true?” with “what is the evidence for and against X?”;
- searching for neutral descriptions before searching for explanations;
- deliberately using alternative terminology that opponents or independent experts might use;
- running parallel searches framed from different starting assumptions;
- comparing whether different queries retrieve substantially different evidence.
These practices widen the evidence considered without requiring people to abandon healthy scepticism or accept every opposing claim. Their value lies in increasing the probability that genuinely informative evidence appears before conclusions become fixed.
The narrow search effect therefore highlights a subtle but important lesson: belief updating depends not only on the quality of available information but also on how people ask for it. By broadening search terms at the outset, individuals improve their chances of discovering evidence that genuinely tests, rather than merely confirms, what they already believe. [PNAS+2bps.org.uk]pnas.orgThe narrow search effect and how broadening…24 Mar 2025 — We demonstrate that the combination of users' prior beliefs influencing…
Amazon book picks
Further Reading
Books and field guides related to Why Searching Can Make Beliefs More Stubborn. Use these as the next step if you want deeper reading beyond the article.
The Scout Mindset
Directly addresses motivated reasoning, intellectual openness, and changing one's mind.
Thinking, Fast and Slow
Explains cognitive biases, belief formation, and why people interpret evidence in biased ways.
Mistakes Were Made (but Not by Me)
Explores self-justification, confirmation bias, and why people cling to existing beliefs.
The Believing Brain
Examines how beliefs are formed first and rationalized afterward, closely matching the page topic.
eBay marketplace picks
Marketplace Samples
Live-tested eBay searches with available results related to this page.
Endnotes
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Source: pnas.org
Link: https://www.pnas.org/doi/10.1073/pnas.2408175122Source snippet
The narrow search effect and how broadening...24 Mar 2025 — We demonstrate that the combination of users' prior beliefs influencing...
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Source: knowledge.uchicago.edu
Link: https://knowledge.uchicago.edu/record/14793Source snippet
UChicago KnowledgeThe narrow search effect and how broadening...by E Leung · 2025 · Cited by 11 — Studies 1 to 5 show that users' prior...
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Source: core.ac.uk
Link: https://core.ac.uk/download/pdf/301367349.pdfSource snippet
erbate confirmation bias by generating results that consist only of confirming evidence for search...Read more...
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Source: bps.org.uk
Title: your search engine queries also maintain your online echo chamber
Link: https://www.bps.org.uk/research-digest/your-search-engine-queries-also-maintain-your-online-echo-chamberSource snippet
The narrow search effect and how broadening search promotes belief updating. Proceedings of the National Academy of Sciences, 122(13)...
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Source: pnas.org
Link: https://www.pnas.org/doi/10.1073/pnas.2221911120Source snippet
Flexible synthesis can deliver more tailored and timely...Jun 14, 2023 — Automated searches combined with natural-language processing ma...
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Source: pnas.org
Link: https://www.pnas.org/toc/pnas/122/44Source snippet
Table of Contents — November 4, 2025, 122 (44)The movement patterns of animals while searching for food have been studied extensively in...
Published: November 4, 2025
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Source: pnas.org
Link: https://www.pnas.org/doi/10.1073/pnas.2304862120Source snippet
Failing to replicate predicts citation declines in psychologyJul 10, 2023 — We found consistent evidence that failing to replicate predic...
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Source: pnas.org
Link: https://www.pnas.org/doi/abs/10.1073/pnas.2408175122Source snippet
The narrow search effect and how broadening...by E Leung · 2025 · Cited by 13 — We demonstrate that the combination of users' prior beli...
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Source: pnas.org
Title: Table of Contents —
Link: https://www.pnas.org/toc/pnas/122/46Source snippet
November 18, 2025, 122 (46)The Euler Characteristic Transform (ECT) of Turner et al. provides a way to statistically analyze nondiffeomor...
Published: November 18, 2025
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Source: pnas.org
Title: Table of Contents —
Link: https://www.pnas.org/toc/pnas/122/20Source snippet
May 20, 2025, 122 (20)A half-century of climate change in major agricultural regions: Trends, impacts, and surprises. Efforts to anticipa...
Published: May 20, 2025
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Source: youtube.com
Title: Episode 9 | The Visibility Brief: How Psychology Shapes [AI Search]({{ ‘ai-search/’ | relative_url }}) and Discovery
Link: https://www.youtube.com/watch?v=WIhZxore53sSource snippet
Confirmation Bias | Ethics Defined...
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Source: youtube.com
Title: Confirmation Bias | Ethics Defined
Link: https://www.youtube.com/watch?v=7zoWTb3KP-kSource snippet
The Most Common Cognitive Bias...
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Source: pubmed.ncbi.nlm.nih.gov
Link: https://pubmed.ncbi.nlm.nih.gov/40127267/Source snippet
The narrow search effect and how broadening...by E Leung · 2025 · Cited by 11 — We demonstrate that the combination of users' prio...
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Source: ncbi.nlm.nih.gov
Link: https://www.ncbi.nlm.nih.gov/clinvar/variation/802880/?new_evidence=trueSource snippet
nih.govVCV000802880.14 - ClinVar - NCBIFour of five in-silico tools predict a benign effect of the variant on protein function.... Last...
Additional References
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Source: thedecisionlab.com
Link: https://thedecisionlab.com/biases/confirmation-biasSource snippet
Confirmation BiasConfirmation bias describes our underlying tendency to notice, focus on, and provide greater credence to evidence that f...
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Source: researchgate.net
Link: https://www.researchgate.net/publication/349693310_Confirmation_bias_in_information_search_interpretation_and_memory_recall_evidence_from_reasoning_about_four_controversial_topicsSource snippet
evidence from reasoning about four controversial topicsThe results showed that confirmation bias was most prevalent in information search...
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Source: academic.oup.com
Link: https://academic.oup.com/pnasnexus/article/4/12/pgaf363/8322299Source snippet
oup.comHigh-value decisions are made quickly, with no consistent...by A Pirrone · 2025 — High-value decisions tend to be made more quickly...
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Source: Wikipedia
Title: Proceedings of the National Academy of Sciences of the United States of America
Link: https://en.wikipedia.org/wiki/Proceedings_of_the_National_Academy_of_Sciences_of_the_United_States_of_AmericaSource snippet
Proceedings of the National Academy of SciencesIt is the official journal of the National Academy of Sciences, published since 1915, a...
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Source: psypost.org
Title: scientists show how youre unknowingly sealing yourself in an information bubble
Link: https://www.psypost.org/scientists-show-how-youre-unknowingly-sealing-yourself-in-an-information-bubble/Source snippet
Scientists show how you're unknowingly sealing yourself in...29 Jun 2025 — The study, “The narrow search effect and how broadening searc...
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Source: facebook.com
Title: för inte så länge sedan ledde sökningen ”varför är vaccin farliga?
Link: https://www.facebook.com/groups/kallkritik/posts/2000043273853202/Source snippet
Modifying search algorithms to provide broader results increased belief updating, fostering a more shared factual understanding. Belief p...
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Source: marketing.wharton.upenn.edu
Link: https://marketing.wharton.upenn.edu/wp-content/uploads/2025/09/leung-urminsky-2025-the-narrow-search-effect-and-how-broadening-search-promotes-belief-updating.pdfSource snippet
narrow search effect and how broadening search...by E Leunga · 2025 · Cited by 13 — Directionally narrow search terms are a modern manif...
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Source: researchgate.net
Link: https://www.researchgate.net/publication/390140594_The_narrow_search_effect_and_how_broadening_search_promotes_belief_updatingSource snippet
The narrow search effect and how broadening...24 Mar 2025 — Studies 1 to 5 show that users' prior beliefs influence the direction of the...
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Source: visualize.jove.com
Link: https://visualize.jove.com/40127267-the-narrow-search-effect-and-how-broadening-search-promotes-belief-updatingSource snippet
narrow search effect and how broadening...28 Sept 2018 — Search algorithms and user beliefs create narrow search results, limiting belie...
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Source: findresearcher.sdu.dk
Link: https://findresearcher.sdu.dk/ws/files/282565971Source snippet
Overall, setting up a LLM and validating the inclusion and exclusion criteria for a narrow review like this might take as much time as...
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