Hindsight bias or “I knew it all along”

szklana kula
szklana kula

Published: 06-02-2022

“I knew it would rain, I had to take an umbrella”, “I knew from the beginning that Spain would be the European Champion”, “I knew this event would be weak” – how many times do we hear such statements? And why don’t people take these umbrellas if they knew it was going to rain? Why did they stress when they watched matches, if they knew who would win anyway and why would they go to events they know in advance will be bad?

This is explained by the hindsight bias. The events that have already occurred seem more predictable to us than they really were. Shortly before the accident at the Chernobyl nuclear power plant, a survey was carried out in the Netherlands, in which, among other things, there were questions about the likelihood of a major accident at the nuclear power plant. Some time after the accident, respondents were asked to recall how high they had rated the probability that such an event might occur. It turned out that after the fact they thought that they estimated the probability higher than they actually did in the previous study (Tyszka, 1999).

Fischhoff (1975 as cited in: Tyszka, 1999) examined the occurrence of hindsight bias in psychotherapists. In his study, one group of psychologists was tasked with assessing the probability that certain results will be achieved by applying a certain type of psychotherapy. The second group of psychologists was informed that psychotherapy had already taken place and certain results had been achieved. Their task was to assess the probability with which it was possible to predict in advance that such results would be achieved. They assessed the probability of these results as higher than the group that assessed them before starting psychotherapy. They were convinced that it was possible to predict with high probability that this was how psychotherapy would end. People who did not know about the results yet were not so sure about it.

The phenomenon of hindsight bias can also lead to blaming victims of violence for what happened to them. This is illustrated by a study (Janoff-Bulman, Carli, 1985 as cited in: Tyszka, 1999), in which participants read a description of a date that differed in the ending in two study groups. One group read on the end the sentence: “The next thing I realized was that he raped me,” while the other group read at the end: “The next thing I realized was that he took me to his home”. The rest of the dating description was exactly the same in both groups. All study participants were asked to rate how likely it was, based on the description of the date (not taking into account the ending), to predict whether it could have led to a rape. In the group that read that the date had ended with rape, the assessment of the chance that it might have ended like this was much higher than in the group that did not know about it. Besides, people who read about rape blamed the woman to a greater extent for her behavior that could have provoke to commit it … They believed that it was known that if she behaved like this, she would be raped, so she could predict it.


Tyszka, T. (1999). Psychologiczne pułapki oceniania i podejmowania decyzji. Gdańsk: Gdańskie Wydawnictwo Psychologiczne.

Author: Maja Kochanowska

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