How Hindsight Bias Affects How We View the Past

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Have you ever noticed that events seem more predictable after they have already happened? The results of an election, for example, often seem more obvious after the tallies have been counted. They say that hindsight is 20/20. In other words, things always seem more obvious and predictable after they have already happened.

In psychology, this is what is referred to as the hindsight bias, and it can have a major impact on not only your beliefs but also on your behaviors. Let's take a closer look at how the hindsight bias works and how it might influence some of the beliefs you hold as well as the decisions you make on a day-to-day basis. 

What Is Hindsight Bias?

The term hindsight bias refers to the tendency people have to view events as more predictable than they really are. Before an event takes place, while you might be able to offer a guess as to the outcome, there is really no way to actually know what's going to happen. 

After an event, people often believe that they knew the outcome of the event before it actually happened. This is why it is often referred to as the "I knew it all along" phenomenon.

After your favorite team loses the Super Bowl, you might feel convinced that you knew they were going to lose (even though you didn't feel that way before the game). The phenomenon has been demonstrated in a number of different situations, including politics and sporting events. In experiments, people often recall their predictions before the event as much stronger than they actually were.

Practical Examples

For example, researchers Dorothee Dietrich and Matthew Olson (1993) asked college students to predict how the U.S. Senate would vote on the confirmation of Supreme Court nominee Clarence Thomas. Prior to the Senate vote, 58% of the participants predicted that he would be confirmed. When students were polled again after Thomas was confirmed, 78% of the participants said that they thought Thomas would be approved.

The hindsight bias is often referred to as the "I-knew-it-all-along phenomenon." It involves the tendency people have to assume that they knew the outcome of an event after the outcome has already been determined.

For example, after attending a baseball game, you might insist that you knew that the winning team was going to win beforehand. High school and college students often experience hindsight bias during the course of their studies.

As they read their course texts, the information may seem easy. "Of course," students often think after reading the results of a study or experiment. "I knew that all along."

This can be a dangerous habit for students to fall into, however, particularly when test time approaches. By assuming that they already knew the information, they might fail to adequately study the test materials.

When it comes to testing time, however, the presence of many different answers on a multiple-choice test may make many students realize that they did not know the material quite as well as they thought they did. By being aware of this potential problem, however, students can develop good study habits to overcome the tendency to assume that they 'knew-it-all-along.'

Explanations of Hindsight Bias

So what exactly causes this bias to happen? Researchers suggest that three key variables interact to contribute to this tendency to see things as more predictable than they really are.

  • Cognitive: People tend to distort or even misremember their earlier predictions about an event. It may be easier to recall information that is consistent with their current knowledge.
  • Metacognitive: When we can easily understand how or why an event happened, that event can seem like it was easily foreseeable.
  • Motivational: People like to think of the world as a predictable place. Believing an outcome was "inevitable" can be comforting for some people.

When all three of these factors occur readily in a situation, the hindsight bias is more likely to occur.

When a movie reaches its end and we discover who the killer really was, we might look back on our memory of the film and misremember our initial impressions of the guilty character. We might also look at all the situations and secondary characters and believe that given these variables, it was clear what was going to happen. You might walk away from the film thinking that you knew it all along, but the reality is that you probably didn't.

One potential problem with this way of thinking is that it can lead to overconfidence. If we mistakenly believe that we have exceptional foresight or intuition, we might become too confident and more likely to take unnecessary risks.

Such risks might be financial, such as placing too much of your nest egg in a risky stock portfolio. They might also be emotional, such as investing too much of yourself in a bad relationship. 

So, is there anything that you can do to counteract the hindsight bias? Researchers Roese and Vohs suggest that one way to counteract this bias is to consider things that might have happened but didn't. By mentally reviewing potential outcomes, people might gain a more balanced view of an outcome's apparent inevitability.

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3 Sources
Verywell Mind uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Pezzo M. Hindsight bias: A primer for motivational researchers. Social and Personality Psychology Compass. 2011;5(9):665-678. doi:10.1111/j.1751-9004.2011.00381.x

  2. Dietrich D, Olson M. A demonstration of hindsight bias using the Thomas confirmation vote. Psychological Reports. 1993;72(2):377-378. doi:10.2466/pr0.1993.72.2.377

  3. Roese NJ, Vohs KD. Hindsight bias. Perspect Psychol Sci. 2012;7(5):411-426. doi:10.1177/1745691612454303

Additional Reading
  • Myers, David G. Social psychology (8 ed.). McGraw-Hill Education; 2005.