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What Is a Hindsight Bias


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The term hindsight bias refers to the tendency people have to view events as more predictable than they really are. After an event, people often believe that they knew the outcome of the event before it actually happened. 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.

For example, researchers Martin Bolt and John Brink (1991) 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-percent of the participants predicted that he would be confirmed. When students were polled again after Thomas was confirmed, 78-percent 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."

As a psychology student, you may have also experienced the hindsight bias in your own studies. As you read your course texts, the information may seem easy. "Of course," you might think after reading the results of a study or experiment. "I knew that all along." When it comes to test time, however, the presence of many different answers on a multiple choice test may make you realize that you did not know the material quite as well as you thought you did. By being aware of this problem, you can develop good study habits to overcome the tendency to assume that you 'knew-it-all-along.'


Myers, David G. (2005). Social psychology (8 ed.). McGraw-Hill Education. pp. 18–19.

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