Cognitive illusion is defined as: “Perception, Judgment, or memory that deviates from reality.” It is an altered perception of a particular situation where the person is unaware that they are not acknowledging reality. It is a challenging task to identify illusions as thoughts are not tangible and can’t be measured. This blog post will provide insights into common cognitive illusions and how they alter our perception.

Common Illusions:

1: Confirmation Bias:

This type of cognitive illusion leads to partial judgment as the individual seeks evidence or information that supports their pre-existing notions. In the case of confirmation bias, people neglect the evidence supporting opposite perspectives and acknowledge only those that support their pre-established conclusion.

It is obvious in a political discussion. Both sides support their perspective without considering the opposite stance, which often leads to futile discussions with no result.

2: Availability:

The availability illusion leads people to believe that the information readily available in their memory is the most important. They tend to overestimate recent happenings while ignoring instances from the past.

For example, when questioning a married couple about their contribution to the household, both partners will likely overestimate their own contribution in the majority of cases. Similarly, in group projects, each team member might emphasize that their contribution is more significant compared to their teammates.

3: Anchoring Effect:

The anchoring effect refers to heavy reliance on the first piece of information while making a decision, even when it is misleading or inaccurate. Alternatively, it can be described as making decisions according to previously established standards.

This kind of bias is often observed in trial judges. The judge may be influenced by journalists or the prosecutor regarding punishment sentences, who have suggested a certain duration of time for punishment.

4: Illusory Correlation:

Illusory correlation is perceiving a relationship between two variables when none actually exists. It may also refer to overestimating the strength of the relationship between two variables due to personal bias.

Examples include young children who can’t differentiate between pleasant and painful stimuli or a false correlation between diseases and symptoms leading to false diagnoses.

5: False Memory:

Studies have shown that people may develop altered memories of events that never happened in reality. False memories are developed as the brain has a tendency to adapt to circumstances.

A person describing a horrific accident that they watched on TV as a real-life event they witnessed. Similarly, children watching a horror movie may remember it as something they experienced in their childhood.

6: Dunning-Kruger Effect:

The Dunning-Kruger effect refers to the tendency of individuals to underestimate or overestimate their abilities. Some people might consider themselves an expert in a particular subject while having little knowledge. Conversely, others might consider themselves inferior even if they have sufficient knowledge.

Unskilled drivers might believe that their newly gained license makes them eligible to take unnecessary risks on the road. Similarly, a novice chess player after winning a few games might think they are a champion now.

7: Halo Effect:

The halo effect refers to the assumption that when a person possesses an admirable quality, they have other admirable qualities as well, even when there is no significant evidence. It also works in the opposite direction. The person may observe a bad quality in an individual and declare them a devil without any evidence.

For example, people might assume that an academically strong student in one subject is exceptional in other subjects as well. Or a physically attractive person possesses other positive qualities such as intelligence, kindness, bravery, etc.

8: Hindsight Bias:

Hindsight bias can be represented as “I already knew it.” This kind of cognitive illusion refers to the false belief that people already predicted the outcome of an event before it occurred. This leads to an illusion of foresight.

After a sports game, the audience might claim that they already knew who was going to win, even when they were unsure of their prediction. After an important invention, people might claim that they knew it was going to be huge while initially being skeptical about it.

9: Labelling Effect:

The labeling effect is also known as the semantic or framing effect. It refers to the powerful effect of language and labels on an individual’s judgment, perception, and decisions about people or objects. This may lead to incorrect judgments and distorted perceptions.

A food item labeled as “organic” might make you think it is healthier compared to an unlabeled one, even when the ingredients are the same in both. Similarly, a person with prestigious job titles such as “CEO” or “Director” is considered more skillful and knowledgeable even if they are not capable in reality.

10: Overconfidence Bias:

The overconfidence bias refers to people’s ability to overestimate their abilities, progress, knowledge, or the accuracy of their beliefs. This type of cognitive illusion makes them believe that they are much more qualified than others. It may lead to underestimating life challenges and poor decision-making.

An investor might believe that they are an expert in the stock market and may take unnecessary risks, causing significant financial losses. Overconfidence bias is also observed in job applicants. Some applicants might overestimate their qualifications and not prepare adequately for the interview. This may lead to poor performance and loss of job opportunities.


Cognitive illusions come in various types and exist in all kinds of circumstances including personal and professional lives. Some of them were discussed above, but minimizing them is a challenge itself. However, recognizing the bias is the first step to improving your judgment. Observe your thoughts and understand them fully to find possible errors. The simple practice of observing and understanding will help you identify thought patterns and prevent them in the future.