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The confirmation bias

The confirmation bias is the tendency to value, remember, interpret or even research information that confirms pre-existing beliefs.

We often develop convictions with ease. Even on complex subjects, most people have an opinion even when they have very little information on the subject. Various biases such as availability or authority contribute to this.

Once an idea has been formed on an issue, we tend to consider it right and develop a lot of resistance in accepting information that contradicts this initial perception.

We stop perceiving reality objectively and actively seek confirmation of this belief. At the same time we ignore or reject any information that contradicts it.

How it is manifested

  • We place more value on evidence that supports our beliefs and devalue those that do not;
  • We look for sources that tend to reinforce our ideas and we avoid those that undermine them;
  • We interpret the data to confirm our thesis, even if they are ambiguous or contradictory;
  • We remember events or information that validate our perspective and forget those that contradict it (“cherry-picking”).

Why is it important?

The confirmation bias is one of the most impacting in our individual and social life.

At the individual level, it can cause a great distortion of perception about various realities and help to create “certainties” based on scarce or unreliable information. It leads to misunderstanding of other perspectives and inappropriate decision-making.

In groups, the confirmation bias helps to strengthen “group thinking“, thus contributing to the formation of collective beliefs and very biased perceptions of reality. The limitation of information, which happens in these situations, sometimes leads to a radicalisation of the group.


  • Many people, because they love a public figure, disregard negative information about it.
  • When we do a search, we tend to look for information that meets our ideas and despise any that goes against them.
  • When (some) politicians take a decision, they tend to justify it later, sometimes even against their own interests.

  • Even scientists tend to privilege evidence that confirms their theories over evidence that contradicts them, which leads to other important biases such as publication.

  • Affiliations (clubistic, ideological, partisan) are largely exposed to this bias. They can also be reinforced or even supported by it.

How to avoid

Cognitive biases cannot be completely eliminated and this is one of the most difficult to counter. However, there are some ways of trying to do this.

  • Before we rush to take a position on an issue we must seek information from credible and diverse sources. Many may seem reliable, but often they are not.
  • Focus on scientific evidence. In social networks and on the internet it is not always easy to find credible sources and this requires a careful search.
  • Even within science we must be cautious. There are some very popular studies, because they are attractive, that are of poor quality. Even the opinions of “experts” (often going beyond their area of competence) should not be regarded as “the truth”. On complex topics there are different views within the scientific community, and the evidence is often contradictory, which suggests some caution.
  • Do not “invest” too much in a perspective based on a first impression or intuition. When there are different theories on a subject it is important not to have a closed position. Even if we have a given vision, we must justify it with concrete data, identify alternative hypotheses and don´t be afraid to change through new evidence.
  • Try to discuss with those who have different perspectives. This can promote a more comprehensive view and prevent the initial biases from getting worse.
  • Avoid forming opinions based on “group thinking”, particularly in groups with pronounced ideological leanings, as this may undermine exemption in the evaluation of information and the creation of dogmas.
  • Try to see how we can be affected by this bias. For example, because we have taken a hasty initial position, because we have too much exposure to one of the perspectives, or because we are an interested party.
  • Practice the difficult task of recognizing evaluation errors and succeeding in redefining positions in the face of new evidence. Encourage others to do so, including by praising this attitude.


We are all strongly influenced by the confirmation bias. When we attach ourselves to a given perspective, we feel our self-esteem at stake and the way to safeguard it is to confirm our positions biasedly. Often unconsciously.

There are factors in modern life that further accentuate the problem. For example, some technologies use filters that, through algorithms, lead us to content that is more enjoyable to us. They tend to reinforce our beliefs, radicalize positions and undermine our critical sense.

We are even more exposed to our limitations, and vulnerable to commercial, political or ideological manipulations.

Fortunately, there are other factors that can counter this trend. It is up to each of us to keep a curious mind, open to new information and with a critical sense.

Although difficult, we need to focus more on uncovering the truth than proving that we were right from the start.

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