Hindsight Bias: I Knew It All Along!

Have You Ever?

Have you ever been to a sports game where both teams were strong, and you weren’t quite sure who would win? You and a friend might have chatted and cheered and been left in suspense for most of the game. Finally, in the last five seconds, the team you were rooting for wins! Your friend shouts, “Yes! I knew they would win all along!” Is this true though? Weren’t you both unsure for the whole game? Why is your friend suddenly so sure that this was always going to be the outcome?

Here’s Why

When the outcome of an event is known, it is easy to say that it was obvious in retrospect. When your friend found out that your team won, they became convinced that they knew victory was guaranteed, even though they were uncertain, just like you.

Hindsight Bias

Hindsight bias is the tendency to overestimate the accuracy of one’s prediction after learning the outcome of an event.

The Experiment

A doctoral student at the Hebrew University of Jerusalem named Baruch Fischhoff was the first one to document the concept of hindsight bias. In his study in 1975, Fischhoff presented five groups of people with a bit of background information about a small conflict between British and Napolese soldiers from 1814. After they read the informative paragraph about the event, he gave each of the four groups a different outcome. The outcomes were things like “British victory” and “military stalemate with a peace settlement.” The fifth group did not have an outcome at the end of their informative paragraph. Finally, Fischhoff had all the participants predict the likelihood of all four results. He found that people in the groups who were given a “known” outcome were more likely to see that specific outcome as obvious.

Why Care?

Further experimentation supported the concept of hindsight bias. One study conducted in 1993 by Dorothee Dietrich and Matthew Olsen demonstrated that people’s confidence in their ability to predict election results is consistent with the idea of hindsight bias. Additionally, in a study conducted in 2012, researchers Colin Camerer and Shinsuke Shimojo found that participants exhibited hindsight bias when they were asked to judge other participants’ ability to identify humans in blurry pictures. 

Hindsight bias often increases people’s confidence in their predictions, to the point where they become overconfident. It happens to people like investors and judges all the time. For example, an investor is likely to see a change in the market as “obvious” after it occurs, so they may regret not investing in the correct thing early enough. In the case of a judge, since the crime or event in question has already happened, it is easy to immediately blame the defendant for an accident that they might not have been able to prevent in that specific moment. Unfortunately for the defendant, this often means that an innocent person can receive jail time and fines because it appears that they could have done something better after the fact.

Hindsight bias happens a lot in some professions, but it can be a problem for everyone. It can lead to false confidence in your abilities to predict the weather, the stock market growth or decline, and your physical and mental capabilities. How often have you read a fact in a textbook and then thought, “I already knew that!” even though five minutes prior, you wouldn’t have been able to list it off? Hindsight bias can create problems daily, so it is essential to be aware of it. 

Now that you know about hindsight bias, you can work on developing your ability to recognize it and realize that your predictions might not always be as accurate as you think they are, especially after you learn the outcome of an event. Use this knowledge wisely to shield yourself from overconfidence in your predictions by constantly reassessing your predictions, and thinking hard about whether your initial predictions were actually correct after you find out the outcome of an event. You might find that admitting when you were wrong can help you learn a lot more, which allows you to become a better, more educated person by attempting to limit your hindsight bias.

Think Further

  1. How have you experienced hindsight bias in your daily life?
  2. How might a different profession experience hindsight bias?
  3. Can you think of any other ways to test hindsight bias?


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Learn More

  1. Fischhoff, Baruch. “Hindsight Is Not Equal to Foresight: The Effect of Outcome Knowledge on Judgment under Uncertainty.” Journal of Experimental Psychology: Human Perception and Performance, vol. 1, no. 3, 1975, pp. 288–299., doi:10.1037/0096-1523.1.3.288.
  2. Inman, Mary. “Hindsight Bias.” Encyclopedia Britannica, 23 May 2016, www.britannica.com/topic/hindsight-bias.
  3. Dwyer, Christopher. “12 Common Biases That Affect How We Make Everyday Decisions.” Psychology Today, Sussex Publishers, 7 Sept. 2018, www.psychologytoday.com/us/blog/thoughts-thinking/201809/12-common-biases-affect-how-we-make-everyday-decisions.
  4. Cherry, Kendra. “How Hindsight Bias Affects How We View the Past.” Verywell Mind, Verywell Mind, 6 May 2020, www.verywellmind.com/what-is-a-hindsight-bias-2795236.
  5. Woo, Marcus. “Reducing 20/20 Hindsight Bias.” California Institute of Technology, 25 Nov. 2012, www.caltech.edu/about/news/reducing-2020-hindsight-bias-37563.