When a learner takes in information, the information becomes knowledge. When knowledge becomes embedded in long-term memory, connecting it to knowledge that is already there embeds the knowledge. The knowledge overlays what is already there.
This is an efficient and brilliant way to track learning. Memory traces that are already there can be slightly modified with the new information and (hopefully) a more accurate internal representation of reality is the result. However, if the knowledge that is already there is inaccurate, the new knowledge will only be as accurate a representation of reality as the foundation that it is tied to.
Cognitive bias is the bias that we see when individuals choose to consume information that supports their current worldview. This is because the new knowledge fits easily with the structure of the knowledge that is already there. The effort to encode information that fits well onto the knowledge with strong memory traces. The knowledge already there is easily available and the new information being transformed into knowledge easily fits.
The real challenge with new knowledge is that when it does not fit well with an internal representation of reality, what do you do with it. You have one of two choices, ignore the information and make no effort to incorporate it into your pre-existing knowledge base, or restructure your current representation of reality in order to comfortably incorporate the new knowledge.
By far, the easiest option of the two is to ignore information that does not align itself with your current internal reality. Much more difficult is the tearing apart your internal reality in order to incorporate new information and make it a part of a transformed internal representation of reality. The restructuring process takes both time and energy. The restructuring process takes work.
This restructuring process represents the ability to self-correct. A painful process that requires the admission that some of your internal representation of reality was wrong. It is not only difficult to admit that you are wrong to others, it is difficult to admit it to yourself as well. As a result, people hold onto their internal representations in a dogmatic fashion that makes long-held beliefs and ways of viewing the world very difficult to change.
However, when a person engages in a formal learning process at any age, they are of a mindset that means that their internal representation of reality is somewhat fluid and open to restructuring. Children are usually learning concrete principles and knowledge for which they have no previous representation. That is one of the reasons children learn so well. It is as though they are a sponge, soaking up everything as they build an initial representation that combines with their environmental experiences to define who they are. As we age, our internal reality becomes more brittle and difficult to restructure. The ability to self-correct is still there, but the willingness to engage in it is lessened because of the difficulty of the challenge.
The adoption of a mindset that is always open to evidence and self-correction is a core attribute of critical thinking. Unfortunately, because of the difficulty of changing our internal representation of reality, critical thinking within our society is in dangerously short supply. Playing a video game, watching television or YouTube is much easier – especially if you can find something that bolsters your already solidly held (and accurate) representation of reality.