The confirmation bias

In my blog last week I mentioned the confirmation bias. I think that I should say a little bit more about it, for it is one of the most important fallacies in human thinking. The confirmation bias is the tendency to look only for evidence that supports your belief, view, opinion and so on. This usually goes together with a tendency to ignore, deny and overlook what doesn’t fit what you already think or want to think. As such this might not be unreasonable, especially if you must take a quick decision. Gathering negative evidence that undermines your ideas often takes much more time than getting positive evidence that supports them. Moreover, for many people it is often quite frustrating to give up what they consider right or to admit that another person was right (certainly if they don’t like him or her). However, the confirmation bias can lead to serious mistakes, for the problem is that you can find confirming evidence for any idea that you want to defend, even if it is false. By considering only positive evidence and ignoring negative evidence, it will not be difficult to “prove” any statement or theory, for instance that Santa exists (don’t we find presents under the Christmas tree each year?). Even more, if we accept only positive evidence for what we belief or think right, we can never prove that it is false, even if it is. That’s why we must be open to counterevidence and be critical towards ourselves. However, studies have shown that we tend to dig in our heels, when we are confronted with evidence that refutes what we consider true.

Several human phenomena can be seen as variants or expressions of the confirmation bias. So, many people listen, watch or read only the media that fit their political views. Conservatives often watch only conservative news channels and liberals watch liberal channels. You find the same selective tendency on the Internet when you use a searching machine like Google, use social media like Facebook etc. But in this case the selective information is also often forced upon you, unknown to you and against your will. It’s called the “filter bubble”. Generally, searching machines select information based on what they “think” that you find interesting in view of your past searching behaviour. This makes that you mainly get information you already agree with, with the effect that the information you get is restricted to your “normative environment”. Critical information is screened out even if you just want to have it. It’s often very difficult to escape the filter bubble, even if you intentionally try it. The machinery works against you.

Cognitive dissonance is another example of the confirmation bias. Say, you expected that the world would be destructed on 2 March 2020. However, the prophecy didn’t come true and now two weeks later the world still exists. You feel quite ill at ease and you try to understand what went wrong. Then you might think: A supreme being has given the world a second chance. According to the theory of cognitive dissonance, you try to reduce the dissonance between your conviction and what actually happened by looking for an explanation that confirms our original view when it seems to fail.

We can also explicitly use the confirmation bias for manipulating others. I found a nice illustration in the Wikipedia, although there it isn’t presented as a case of manipulation but as an example of the influence of a question’s wording on the way people look for information in order to answer the question. Here it is: Participants in a test of a fictional child custody case “read that Parent A was moderately suitable to be the guardian in multiple ways. Parent B had a mix of salient positive and negative qualities: a close relationship with the child but a job that would take them away for long periods of time. When asked, ‘Which parent should have custody of the child?’ the majority of participants chose Parent B, looking mainly for positive attributes. However, when asked, ‘Which parent should be denied custody of the child?’ they looked for negative attributes and the majority answered that Parent B should be denied custody, implying that Parent A should have custody.” (https://en.wikipedia.org/wiki/Confirmation_bias, section 1.1) This example illustrates that the answer to a question often is dependent on the its wording. So, by “cleverly” asking questions you can “push” people to give the answers you want to have. One step further then is presenting the answers as the way people “really” think about a certain theme.

It will not be difficult to find more striking cases of the confirmation bias. They make clear that as such it is not bad to look for confirming information of your views, but often it can disturb your thinking and lead to false ideas. So, beware of what you believe and be open to what can undermine what you take as true. And now that you know what the confirmation bias is, you’ll certainly see it everywhere.

Sources

Arp et al. 2019 (see blog last week); Wikipedia (see above).