Seeing What We Want to See: Understanding Confirmation Bias
Written by Kendra Wang
How much do your beliefs reflect reality? This question confronts us all, challenging our fundamental understanding of the world. Yet, what if I told you that your beliefs might be incorrect far more than you think? In our minds, there exists a silent yet persistent force that influences our everyday perceptions, decisions, and reality: confirmation bias. Confirmation bias causes us to seek and interpret new information in a way that favours our pre-existing beliefs (Nickerson, 1998). Under this influence, we filter information to value evidence that affirms our opinions while neglecting information that contradicts what we already think.
To further understand confirmation bias, let's play a game! I am thinking of a pattern for a three-number sequence; “2-4-6” is an example of a sequence that satisfies my pattern. Your task is to determine what my rule is by testing more sequences. I will tell you whether your guesses fit my rule. Please pause to consider a few sequences that you might test to determine my rule.
This prompt was used in a famous study that investigated confirmation bias (Wason, 1960). Keeping your test sequences in mind from earlier, read on to discover if you approached the experiment similarly to the participants in the study.
The participants first used the clue “2-4-6” to infer that the rule would be “even numbers ascending by two.” They then tested their theory by guessing sequences that fit their idea of the rule (e.g. “8-10-12,” “22-24-26”). When the examiner confirmed that their sequences satisfied the rule, the participants felt confident and offered their final answer. However, their answer was wrong. Actually, the examiner’s rule was simply “a sequence of ascending numbers,” but the participants couldn’t have discovered this without testing sequences that contradicted their initial theories. The participants attempted to confirm their ideas instead of attempting to falsify them (Oswald & Grosjean, 2004). Although there were no consequences for guessing incorrect sequences, the participants avoided testing sequences that might be wrong. This simple demonstration shows that people seek positive rather than negative feedback. This behaviour is an example of confirmation bias.
But why does this matter; why should we care about confirmation bias? Although the example above seems relatively harmless, confirmation bias often has real consequences.
For instance, studies have shown that psychiatrists are susceptible to confirmation bias (Mendel et al., 2011). For example, a psychiatrist who made a preliminary diagnosis of ADHD for a patient will search mainly for symptoms of ADHD in that patient to confirm their initial assumption. In this process, the psychiatrist will disregard evidence that suggests a different condition. This selective evidence-searching can lead to misdiagnoses if the initial diagnosis is incorrect (Mendel et al., 2011). Such misdiagnoses may consequentially result in inappropriate treatments, exposure to unnecessary risks, and a failure to care for the patient’s condition properly. According to a 2011 study, 25% of students and 13% of psychiatrists demonstrated confirmation bias in this manner (Mendel et al., 2011).
In essence, this biased form of information processing causes the information seeker to maintain their pre-established beliefs, regardless of how unjustified their position might be (Johnston, 1996). The implication is that confirmation bias can prohibit learning entirely. When this is applied to everyday affairs such as personal learning, medical diagnoses, and judicial decisions, the consequences can be grave.
The repercussions of confirmation bias are evident, yet why does it still happen to us — students, lawyers, and doctors alike? People enjoy receiving positive feedback, so they tend to favour affirming information (Swann Jr. et al., 1989; Swann Jr. & Read, 1981). When people discover evidence that supports their pre-existing beliefs, it boosts their confidence. This then provides people with a feeling of validation. Similarly, information that challenges their beliefs provokes discomfort. Thus, people subconsciously disregard negative feedback to avoid uneasiness (Swann Jr. & Read, 1981). Lastly, confirmation bias can help people process information more quickly. By favouring information that affirms one's pre-existing beliefs and filtering out contradictory viewpoints, confirmation bias helps people process information and allows individuals to reach conclusions easily. In short, confirmation bias exploits these natural tendencies and “shortcuts” in how humans process information — ultimately making this bias an irresistible behaviour that plagues many.
The truth is, it is unlikely that we can ever eliminate confirmation bias. However, we can try to control it through conscious efforts. Learning about confirmation bias and recognizing when you might be experiencing it is already one step in the right direction; if you are interested in exploring this further, check out this recent review for further insights on confirmation bias. When you notice this bias at play, you may combat it by considering all perspectives available and actively seeking disconfirming evidence. Virtually anyone can benefit from keeping an open mind. This commendable skill can help substantially to reduce the presence and harm of confirmation bias — aligning our beliefs more closely with the nuanced realities of the world around us.
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References
Casu, M., Guarnera, L., Caponnetto, P., & Battiato, S. (2024). GenAI mirage: The impostor bias and the deepfake detection challenge in the era of artificial illusions. Forensic Science International: Digital Investigation, 50, 301795. https://doi.org/10.1016/j.fsidi.2024.301795
Jonas, E., Schulz-Hardt, S., Frey, D., & Thelen, N. (2001). Confirmation bias in sequential information search after preliminary decisions: An expansion of dissonance theoretical research on selective exposure to information. Journal of Personality and Social Psychology, 80(4), 557. https://doi.org/10.1037/0022-3514.80.4.557
Mendel, R., Traut-Mattausch, E., Jonas, E., Leucht, S., Kane, J. M., Maino, K., Kissling, W., & Hamann, J. (2011). Confirmation bias: Why psychiatrists stick to wrong preliminary diagnoses. Psychological Medicine, 41(12), 2651. https://doi.org/10.1017/s0033291711000808
Nickerson, R. S. (1998). Confirmation bias: A ubiquitous phenomenon in many guises. Review of General Psychology, 2(2), 175–176. https://doi.org/10.1037/1089-2680.2.2.175
Oswald, M. E., & Grosjean, S. (2004). Confirmation Bias. In R. F. Pohl (Ed.), Cognitive illusions: A handbook on Fallacies and biases in thinking, judgement and memory, 79-80. https://doi.org/10.13140/2.1.2068.0641
Swann Jr., W. B., & Read, S. J. (1981). Self-verification processes: How we sustain our self-conceptions. Journal of Experimental Social Psychology, 17(4), 351–353. https://doi.org/10.1016/0022-1031(81)90043-3
Swann, W. B., Pelham, B. W., & Krull, D. S. (1989). Agreeable fancy or disagreeable truth? Reconciling self-enhancement and self-verification. Journal of Personality and Social Psychology, 57(5), 782–783. https://doi.org/10.1037/0022-3514.57.5.782
Wason, P. C. (1960). On the failure to eliminate hypotheses in a conceptual task. Quarterly Journal of Experimental Psychology, 12(3), 129–140. https://doi.org/10.1080/17470216008416717
Disclaimer
The blog posts are for informational and educational purposes only. The posts should not be considered as any type of advice (medical, mental health, legal, and/or religious advice). All blog posts have been researched, written, and edited by the undergraduate students and alumni of the Lifespan Cognition Lab. As a teaching and research-based lab, we encourage all lab members to help make knowledge more accessible to all communities through these posts.
