Confirmation bias is the tendency to search for, interpret, favor, and recall information in a way that confirms or strengthens one’s prior personal beliefs or hypotheses. It is a type of cognitive bias. People display this bias when they gather or remember information selectively, or when they interpret it in a biased way. The effect is stronger for desired outcomes, for emotionally charged issues, and for deeply entrenched beliefs. Confirmation bias cannot be eliminated entirely, but it can be managed to improve decision making.
What is confirmation bias?
Confirmation bias is a cognitive bias that involves favoring information that confirms your previously existing beliefs or biases. This inherently involves selectively collecting evidence that supports what you already believe while ignoring or undervaluing any evidence that could disprove your beliefs. As a result of the selective collection and interpretation of evidence, confirmation bias can lead to overconfidence in personal beliefs and judgments. People display this tendency when they gather or remember information selectively, or when they interpret it in a biased way. The effect is stronger for emotionally charged issues and for deeply entrenched beliefs. In addition, people also interpret ambiguous evidence as supporting their existing position. Biased search, interpretation and memory have been invoked to explain attitude polarization, belief perseverance, the irrational primacy effect and illusory correlation.
In psychology and cognitive science, confirmation bias is a pervasive concept: it is of interest in social psychology, personality psychology, and cognitive psychology and biases related to confirmation bias are studied in philosophy and statistics. Confirmation bias, as a phenomenon in psychopathology, has been described over the years by numerous psychiatrists, including Leo Alexander in the course of the Nuremberg Trials, and Laurence Kirmayer. According to Kirmayer, “personal experience inclines us to place faith in our intuitive beliefs, however improbable they are.” He continues, “The scientific method requires us to step back from our intuitions and test them. Rigorous critical thinking obliges us to face the possibility that a favored hypothesis may be wrong.”
Examples of confirmation bias
Politics
In politics, confirmation bias can cause adherents of a political party or ideology to collect and recall information that supports their pre-existing viewpoints while interpreting contradictory information as insignificant or unreliable. Individuals are often overly confident in their views and tend to deny the possibility that their views are incorrect. They also tend to believe that those who disagree with them are biased, irrational or ill-informed.
For example, during the 2016 U.S. presidential election, supporters of Donald Trump shared stories about crimes committed by immigrants more often than crimes committed by those born in the United States, illustrating confirmation bias through their tendency to interpret evidence in a way that validated their political beliefs. Similarly, supporters of Hillary Clinton focused on evidence of Trump’s dishonesty while overlooking or excusing evidence of her own.
Science
In science, confirmation bias can influence the process of gathering data or interpreting results. Scientists may be more likely to accept evidence that confirms their hypothesis and more critically question evidence that disproves it. They may also be more likely to publish positive results over negative ones. This type of bias has been identified as a common hindrance to the scientific method.
For example, early studies of a phenomenon may find a correlation between A and B, and future studies would then tend to find more supportive evidence for the connection. However, later studies that do not reproduce the original results receive little attention. As a result, the positive results receive more focus and confidence in the existence of the effect is strengthened, regardless of what the bulk of the data supports.
Law enforcement
In criminal investigations and law enforcement, confirmation bias can influence the collection of evidence and case construction. Police officers may consciously look for evidence that confirms existing suspicions about a suspect while subconsciously dismissing evidence that points elsewhere. Fact finders such as judges and juries may also seek out information that reinforces their existing views. This bias can result in failures to consider alternative suspects and wrongful convictions.
For example, if police believe a suspect is guilty, they may construct the case around proving that hypothesis while overlooking evidence that suggests innocence. Interrogations may involve leading questions or putting pressure on witnesses. As a result, recollections become skewed or distorted in a way that supports the assumption of guilt.
Recruiting and hiring
During recruitment and hiring processes, confirmation bias can influence how resumes and applications are evaluated. Recruiters or managers may screen for information that matches their predetermined criteria of a good candidate while dismissing information that doesn’t align with their expectations.
For example, if a manager assumes that a suitable candidate must have an Ivy League education, they may focus on applicants who list those schools while disregarding strong candidates from less prestigious institutions. Or if they believe that high academic achievement indicates success on the job, they might overweight GPAs and test scores. This bias limits the number of qualified applicants they seriously consider for the role.
Relationships
In interpersonal relationships, confirmation bias can lead people to seek out or interpret information in a way that suits their preconceived notions about a partner, family member or friend. People may cling to evidence that reinforces their existing views of their spouse, while ignoring or explaining away actions or comments that contradict those views.
For example, someone who thinks their partner is angry with them may interpret ambiguous behaviors like lack of text responses as proof of their assumption. They may not consider more benign explanations like their partner being busy at work. As a result, they strengthen their confirmation bias by reaffirming their unproven belief.
Memory
Confirmation bias affects the way people remember events to reinforce their expectations, even if those recollections are incorrect. People are more likely to remember information that confirms their preconceptions.
For example, fans watching a sports match are more likely to remember good plays made by members of their favorite team and bad plays by the opposing team, even if their overall play quality was comparable. They may also recall the match as being closer than the actual score if that better fits their assumption of it being a tight game.
Gambling
Confirmation bias can lead gamblers to perceive patterns in truly random events. If a person wins big after wearing their “lucky shirt,” they may continue wearing it despite the outcome being entirely due to chance. The person remembers and focuses on the times they won in that shirt while dismissing or forgetting the times they lost while wearing it.
This bias also causes gamblers to rely too heavily on systems or strategies that seem to work but do not necessarily influence long-term results. A gambler may remember the occasions a system worked but not pay attention to the overall house edge.
Advertising
In advertising, marketers attempt to take advantage of confirmation bias by tailoring their messaging to appeal to existing attitudes and preferences. Rather than attempting to change minds, ads can aim to reinforce what viewers already believe or assume to be true.
For example, an ad promoting a new SUV might emphasize its power and off-road capabilities if the target demographic tends to value those attributes and identify them as necessary for a “real” SUV. The ad seeks to confirm those preconceptions rather than convince viewers they might prefer something different.
Finance
Confirmation bias routinely affects investing as people favor information that confirms their beliefs regarding a company or the market as a whole. Investors tend to overweight data that affirms their decision to buy or sell stocks and ignore evidence that suggests they are wrong.
For example, an investor that purchases stock in a company may interpret positive news coverage as validation that it was a good investment. They may dismiss any negative coverage as temporary or an overreaction. As a result, confirmation bias can exacerbate losses on poorly performing stocks.
Health
In healthcare, confirmation bias can cause patients and doctors to emphasize evidence that confirms a diagnosis over ruling it out. They may ask questions that produce answers supporting the hypothesis or dismiss test results that point to alternative conditions.
For example, if a doctor suspects their patient has a particular illness, they may pay more attention to symptoms that align with that illness than those that may indicate something else. As a result, they may order tests that confirm their suspicion rather than first testing for other reasonable possibilities.
Technology
Confirmation bias shapes the way people interact with technology like social media and search engines. Content that confirms someone’s beliefs or views tends to gain more likes, shares, and engagement on social platforms. People also tend to craft queries intended to produce results that affirm their assumptions.
For example, someone that believes vaccines are dangerous may run targeted searches on platforms like Facebook or YouTube for content that supports those views rather than evidence that contradicts them. The algorithms then serve up more similar content, reinforcing the bias.
How can confirmation bias impact decisions?
Confirmation bias can influence people’s opinions and attitudes, how they perceive events, and how they make decisions. In many cases, confirmation bias can exacerbate poor judgment, leading to inaccurate assessments. It impacts decision-making processes like:
- Evaluating information – People place more weight on details that confirm pre-existing views while dismissing contradictory evidence.
- Interpreting events – Individuals may skew perceptions of events to align with their expectations, even if that contradicts objective facts.
- Assessing arguments – People tend to more readily accept arguments and positions that match their own opinions.
- Recalling details – Details that support a person’s existing views are more likely to be remembered accurately.
- Making predictions – Predictions tend to align with someone’s hypotheses and existing way of thinking.
- Seeking evidence – The evidence people look for and collect tends to be selective and biased toward confirmation.
In all of these examples, confirmation bias limits objective analysis and promotes faulty reasoning. Decisions based on biased evidence rarely lead to optimal outcomes. Confirmation bias perpetuates close-minded thinking, inaccurate beliefs and poor judgment.
Does confirmation bias affect beliefs?
Yes, confirmation bias strongly reinforces existing beliefs and makes people less receptive to alternate ideas, viewpoints, or information. When people selectively gather and interpret evidence to support their beliefs, it strengthens their conviction that their views are correct. This makes them less open to questioning their opinions or changing their mind when presented with counter evidence.
In some cases, confirmation bias can lead to strengthening faulty or even dangerous beliefs. For example, gathering selective information from questionable sources may solidify conspiracy theories or extreme viewpoints detached from facts. Confirmation bias contributes to overconfidence and perpetuates beliefs that do not align with reality.
Can confirmation bias be avoided?
Complete avoidance of confirmation bias is likely impossible since it is an innate cognitive trait shared by all human beings. However, there are strategies that can help identify and manage confirmation bias to reduce its effects on decision making and belief formation:
- Seek out alternative viewpoints – Proactively look for sources, opinions, and evidence that contradict your views rather than just reinforcing ones.
- Question assumptions – Continuously re-evaluate your beliefs and hypotheses rather than assuming they are absolutely correct.
- Consider contradictory explanations – Entertain other reasonable conclusions from evidence rather than defaulting to the ones that fit your narrative.
- Analyze motivation – Recognize personal motivations that may subconsciously guide information searches and interpretations.
- Focus on facts – Emphasize objective, empirical evidence over personal anecdotes and experiences.
- Consult others – Seek input from people likely to challenge your thinking rather than just those who agree with you.
While confirmation bias cannot be eliminated, purposeful steps can be taken to minimize its influence over reasoning and decisions.
How can you tell if someone is experiencing confirmation bias?
There are several indicators that suggest an individual may be exhibiting confirmation bias:
- They seek out information that aligns with their existing beliefs.
- They interpret evidence in a way that supports their hypotheses.
- They dismiss or downplay facts that contradict their assumptions.
- They remember details that reinforce their biases better than ones that oppose them.
- Their opinions remain stagnant regardless of counterarguments or new information.
- They surround themselves with sources and individuals who share the same views.
- Their conclusions always seem to match their predictions and expectations.
- They struggle to consider alternative perspectives or arguments.
The presence of one or more of these signs points to a likelihood that confirmation bias is influencing the person’s thought processes and conclusions.
Does everyone have some degree of confirmation bias?
Yes, confirmation bias appears to be a universal human trait. Extensive psychological research indicates that every individual is susceptible to seeking and interpreting evidence in a biased manner that aligns with their existing beliefs and expectations. Challenging one’s own views and considering contradictory information is difficult, requiring purposeful cognitive effort.
People can have more or less awareness of their own confirmation biases. But even those who actively try to avoid it cannot eliminate it completely. Factors like cognitive ability, education level, intelligence, and open-mindedness can influence someone’s self-awareness of confirmation bias. However, all human reasoning contains at least some degree of preferential treatment toward confirming existing hypotheses.
Conclusion
Confirmation bias influences how people gather, interpret, and recall information by making them prone to prioritizing details that conform to their existing beliefs. It can reinforce potentially inaccurate beliefs and viewpoints through selective evidence collection and interpretation. While impossible to eliminate fully, being aware of confirmation bias can help reduce its harmful effects on judgment and decision-making through more balanced reasoning and analysis.