Did you really know it all along? – The dangers of hindsight bias
Written by Liam Ruel
On September 11th, 2001, terrorists hijacked four planes in the United States, two of which were flown into the twin towers of New York’s World Trade Centre (Divine, 2002). Following the completely unpredictable attack, the public accused then-president George Bush of ignoring vital signs of the attack, allowing thousands of innocent citizens to lose their lives. Although some evidence might have predicted the attack, nobody would have connected it with the events of 9/11 until after the attack. In reality, there was no way the attack could have been predicted, let alone prevented.
This event, and many others over the course of history, are examples of hindsight bias – the tendency to think that a past event was more predictable after knowing its outcome. Humans struggle to ignore information when making decisions, because it can provide valuable context to inform their choice. Unfortunately, in the case of hindsight bias, being unable to ignore certain information might not always be a good thing. It can over-inflate one’s confidence in the ability to make decisions, increase the likelihood of risky decisions in the future, and leave one with feelings of anger and frustration when things don’t work out as expected. Research suggests that people of all ages show hindsight bias (Bernstein et al., 2011) and that it can be very difficult to avoid or prevent (Pezzo, 2010). Because of this, hindsight bias can – and does – impact many aspects of life.
But why does this happen? Hindsight bias commonly leads to distortions in memory when people mistakenly believe that they predicted an event that they really didn’t predict (Roese and Vohs, 2012). Further, people can come to think that they knew an event was going to take place. These feelings of foreseeability are responsible for the bulk of hindsight bias’ negative effects. If someone believes that they could accurately predict the outcome of an event because of hindsight bias, they might believe they could predict the outcome of future events, even when this is not probable. Even when one outcome seems far more likely than any others, there will always be a chance that something could happen to change these odds, making it nearly impossible to be 100% certain of an event’s outcome. For example, a study by Giroux et al., asked people to estimate the frequency of COVID-19 deaths and cases in different countries. 8-10 weeks later, these participants were told the exact case numbers and asked to recall their previous guesses. Participants’ recalled guesses were much closer to the exact statistics than their original guesses, indicating memory distortions. Hindsight bias plays a large role in gambling behaviour, specifically around the way gambling outcomes are perceived (Gilovich, 1983). People often report that they accurately predicted the outcome of a gambling attempt even if this was not the case. They come to believe that they can accurately predict gambling outcomes, motivating them to continue.
Hindsight bias also has serious implications for medical diagnoses. When people are asked to evaluate the competence of healthcare workers who provide the same treatment to different patients with the same symptoms, their ratings are heavily dependent on the patient’s health outcome. If two patients are given the same treatment, but one patient dies of their condition while the other makes a full recovery, the healthcare worker is rated as much less competent in the latter case. (Banham-Hall and Stevens, 2019). Decisions around medical malpractice tend to be heavily influenced by hindsight bias, with jurors believing it should have been much easier than it really was to select the right treatment or diagnosis for a patient (Arkes, 2013). Because of this, some healthcare workers focus on avoiding any potential malpractice claims that could jeopardize their career (Bishop et al., 2010). This means that even if a healthcare worker is certain of the problem, they will evaluate every possible diagnosis and treatment path before taking action. Unfortunately, this process could significantly delay treatment for the patient in question, as well as others waiting for care. In time-sensitive situations, this could even result in a patient’s death.
Another area heavily impacted by hindsight bias is the courtroom. Jurors need to ignore their knowledge of the outcome of the event in order to make unbiased decisions about the guilt of a defendant. (Harley, 2007). This allows them to make a decision based on the risks associated with the defendant’s actions, without being biased by the damages those actions caused. For example, imagine jurors evaluating the cases of two people who ran a red light, based on the resulting damage. Knowing the outcome that damages resulted might result in different conclusions about each individual’s guilt or innocence. If one defendant collided with oncoming traffic resulting in the death or injury of others, jurors may believe they were more guilty than the other defendant who simply ran the light without causing significant harm. Although both defendants chose to make the risky decision of running the light, and both had the potential to cause a great deal of damage, their cases may not be evaluated equally. Hindsight bias is found more often in legal cases with strong negative outcomes, with jurors being much more likely to find defendants guilty (Harley, 2007; Giroux et al., 2016). As a result, people may not be punished fairly for their actions – potentially meaning excessive jail time or restrictions.
So what does all of this mean? Since hindsight bias is very difficult to prevent or avoid, it’s important to evaluate how it could influence your decisions in high-stake situations. Even if you can’t eliminate hindsight bias, taking a minute to consider whether your confidence in a past event is warranted could help you make more informed decisions down the road.
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References
Arkes, H. R. (2013). The consequences of the hindsight bias in medical decision making. Current Directions in Psychological Science, 22(5), 356–360. https://doi.org/10.1177/0963721413489988
Banham-Hall, E., & Stevens, S. (2019). Hindsight bias critically impacts on clinicians’ assessment of care quality in Retrospective case note review. Clinical Medicine, 19(1), 16–21. https://doi.org/10.7861/clinmedicine.19-1-16
Bernstein, D. M., Erdfelder, E., Meltzoff, A. N., Peria, W., & Loftus, G. R. (2011). "hindsight bias from 3 to 95 years of age": Correction to Bernstein et al. (2011). Journal of Experimental Psychology: Learning, Memory, and Cognition, 37(3), 800–800. https://doi.org/10.1037/a0023586
Bishop, T. F., Federman, A. D., & Keyhani, S. (2010). Physicians’ views on defensive medicine: A national survey. Archives of Internal Medicine, 170(12), 1081–1083. https://doi.org/10.1001/archinternmed.2010.155
Columbian College of Arts & Sciences. (2002, May). Could 9-11 have been predicted? Retrieved May 2022, from https://historynewsnetwork.org/article/749.
Gilovich, T. (1983). Biased evaluation and persistence in gambling. Journal of Personality and Social Psychology, 44(6), 1110–1126. https://doi.org/10.1037/0022-3514.44.6.1110
Giroux, M. E., Coburn, P. I., Harley, E. M., Connolly, D. A., & Bernstein, D. M. (2016). Hindsight bias and law. Zeitschrift Für Psychologie, 224(3), 190–203. https://doi.org/10.1027/2151-2604/a000253
Giroux, M. E., Derksen, D. G., Coburn, P. I., & Bernstein, D. M. (2022). Hindsight bias and covid-19: Hindsight was not 20/20 in 2020. Journal of Applied Research in Memory and Cognition. https://doi.org/10.1037/mac0000033
Harley, E. M. (2007). Hindsight bias in legal decision making. Social Cognition, 25(1), 48–63. https://doi.org/10.1521/soco.2007.25.1.48
Pezzo, M. (2003). Surprise, defence, or making sense: What removes hindsight bias? Memory, 11(4-5), 421–441. https://doi.org/10.1080/09658210244000603
Roese, N. J., & Vohs, K. D. (2012). Hindsight bias. Perspectives on Psychological Science, 7(5), 411–426. https://doi.org/10.1177/1745691612454303
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.
