List of Common Cognitive Biases

Cognitive bias can be very subtle. You may not even realize that they are influencing you by:

  • Influencing your beliefs;
  • Distorting your thinking;
  • Swaying your judgment.

This happens because our brains naturally rely on mental shortcuts in order to make decisions more quickly. We couldn’t possibly evaluate every single detail and possible scenario when we need to form an opinion, and this is when cognitive bias may play an important role.

This article will illustrate the most common types of cognitive biases. Even though some of the following biases are inevitable, knowing them will help you make better decisions.

The Actor-Observer Bias

When we witness other people’s actions, especially when they make a mistake, we are more likely to attribute their behavior to internal causes, such as:

  • Their being lazy;
  • Their lack of incompetence;
  • Their lack of intelligence.

Instead, when we need to justify our mistakes, we tend to attribute them to external causes, such as:

  • The test being too difficult for the level required;
  • The lack of sleep;
  • Other people’s bad influence.

In the first case, we are the observers. In the second, the actors. This makes a huge difference in our judgment. We go easier on ourselves because we are aware of our thoughts and intentions. Instead, when we judge others, we lack empathy and do not take into account all of the variables that may have played a role.

The Anchoring bias

The anchoring bias is the tendency to be influenced by the very first piece of information we hear, called anchor, that we adjust to before making a decision. For example, before buying a new car or a new house, it is very common to try to estimate what the average price is and stick to that to negotiate. To combat this anchoring bias, you should instead come up with a range of possible prices that are reasonable to you and forget the overall average price.

Currently, we do not fully understand what causes this bias. The factors that may play a role include:

  • The source of the anchor information;
  • Priming;
  • Mood.

Knowing this bias will help you consider other factors before making a decision.

The Availability Heuristic

The availability heuristic is a mental shortcut that allows us to make decisions more quickly, by estimating the probability of something happening based on the examples we can think of. For example, we might think that plane crashes happen more often than they actually do because we can easily think of many different examples.

This will inevitably lead to poor estimation, and poor decisions as a consequence.

The Confirmation Bias

We are always more likely to listen to those who validate and confirm our original opinion. This means that we often let out or don’t consider important information simply because it would lead us to reconsider our position.

We do this in order to:

  • Preserve our self-esteem;
  • Limit the use of mental resources.

This behavior will inevitably lead to:

  • Poor choices;
  • Inability to listen to opposing view;
  • A limited or distorted way of thinking;
  • Inability to confront people with different opinions.

Example of this behavior include:

  • Only following people on social media who validate your beliefs;
  • Only paying attention to information that confirms your beliefs;
  • Not considering all of the facts in a logical and rational manner;
  • Refusing to listen to those who think differently.

Knowing this mechanism will help you remember that you need as much information as possible before making a decision or forming an opinion.

The False Consensus effect

We often tend to overestimate how much other people agree with us and think that most people share our same values. This is called “the False Consensus effect”.

This happens for several different reasons, including:

  • The time spent with our family and friends, with whom we share similar opinions and values. This leads us to think that this small group of people is a valid representation of the rest of the world, but this might not be the case;
  • Believing that others think like us helps us feel normal and increases our self-esteem.

The false consensus bias can lead to an overvaluation of one’s personal opinions and to not consider other points of views before making a decision.

The Halo Effect

Also known as the “Physical attractiveness stereotype”, the Halo effect is the tendency to judge a person based on their physical appearance.

This applies to:

  • People. If someone is good-looking, we are more likely to think that they are funnier, kinder and smarter;
  • Products. If a product is sponsored by attractive people, we tend to think it is a good product.

This process is influenced by our need to validate our opinions. We want to always be right, even when it comes to a simple first impression.

It is extremely important to acknowledge this bias because we might discard valid people based on their appearance, for example during job interviews.

The Hindsight Bias

The hindsight bias is what makes us think that a particular event was more predictable than it actually was. This happens because we often tend to misremember our previous predictions and because we need to always feel in control of the events.

Examples of this behavior include:

  • Insisting that you knew the outcome of an event once it is over;
  • Often repeating something on the lines of “I knew it all along”;
  • Saying that you knew you weren’t going to win after losing a competition.

Knowing you tend to overestimate your abilities will help you think more objectively and avoid poor decisions.

The Misinformation effect

Unfortunately, our memories do not always mirror the actual event. Instead, they can be heavily influenced by:

  • Questions asked in a certain way;
  • Watching television coverage;
  • Hearing other people talk from a different perspective.

This means that memories are not entirely reliable and need to be validated before making a decision, even if we remember them vividly.

The Optimism Bias

Optimism is not necessarily a positive influence on the decision-making process. It was shown that people tend to ignore negative factors when they need to make an estimation. This is due to the human tendency to believe that bad things can happen to others but not to us. People are also more likely to blame the victims for what happened to them, instead of acknowledging the fact that it could have happened to anyone else.

This is called optimism bias and leads us to underestimate the likelihood of bad experiences in our life. Knowing that can prevent us from making poor decisions based on faulty reasons.

The Self-Serving Bias

We often tend to give ourselves credit for our successes. Instead, we blame others or external causes when we fail. This is called self-serving bias.

In other words, when we succeed we think we deserved it by working hard. When we fail, we look for external explanations that do not depend on us.

This happens because we need to protect our self-esteem, but can also lead to poor self-evaluation.

Other Kinds of Cognitive Bias

  • Apophenia, the tendency to perceive patterns in random occurrences;
  • Framing, the tendency to present a situation in a way that gives a specific impression;
  • Status quo bias, reflecting a desire to keep things as they are and refuse change, even when it is for the best.


Cognitive bias can influence us without us even noticing. Being aware of such mechanisms will help us make better decisions, taking all factors into account.


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