Cognitive Biases: What They Are and How They Affect You

Cognitive Biases


A cognitive bias is a systematic pattern of deviation from rationality, which occurs due to the way our cognitive system works. Accordingly, cognitive biases cause us to be irrational in the way we search for, evaluate, interpret, judge, use, and remember information, as well as in the way we make decisions.

For example, one well-known cognitive bias is the illusion of transparency, which causes us to believe that our thoughts and emotions are more apparent to others than is actually the case. We experience this bias because when we try to assess how other people see us, it’s hard for us to adjust from the anchor of our own view of ourself.

Cognitive biases affect our thought process in every area of life, from how we form our memories, to how we shape our beliefs, and to how we connect with other people.

These patterns of irrationality vary in terms of the way they affect us and in terms of how strongly they do so. Accordingly, cognitive biases can lead to anything from minor issues, such as forgetting a small detail from a past event, to major issues, such as choosing to avoid an important medical treatment that could save our life.

Because cognitive biases have such a pervasive influence, it’s important to understand them. As such, in the following article you will learn more about cognitive biases, understand why we experience them, see what types of them exist, and find out what you can do in order to mitigate them successfully.


Examples of cognitive biases

One example of a well-known cognitive bias is the halo effect, which is a cognitive bias that causes our impression of someone or something in one domain to influence our impression of them in other domains. The halo effect means, for example, that when we think someone is physically attractive, we tend to believe that they are also more knowledgeable and have a better personality compared to what we would think if they were unattractive.

Another example of a cognitive bias is the illusion of control, which is a cognitive bias that causes us to overestimate our ability to control the outcome of situations where chance plays a greater role than skill. The illusion of control means, for example, that we might overestimate our ability to succeed in a risky business venture, even if that venture is likely to fail regardless of how much effort we put into it.

Another example of a cognitive bias is the outgroup homogeneity bias, which causes people to perceive members of outside groups as being more similar to each other than members of groups that they are a part of. This happens primarily because people tend to allocate more of their attention to members of their own group, since interactions with those people are often perceived as more important.

In addition, other examples of cognitive biases include the following:

  • The rhyme-as-reason effect. The rhyme-as-reason effect is a cognitive bias that makes people more likely to remember, repeat, and believe statements that contain a rhyme, compared to those that do not. For example, people generally perceive the aphorism “woes unite foes” as more accurate than the aphorisms “woes unite enemies” or “misfortunes unite foes”, despite the fact that they all mean roughly the same thing.
  • The zero-sum bias. The zero-sum bias is a cognitive bias that causes people to mistakenly view certain situations as being zero-sum, meaning that they incorrectly believe that one party’s gains are directly balanced by other parties’ losses. For example, the zero-sum bias can cause people to think that there is competition for a resource that they feel is limited, in situations where the resource in question is actually unlimited and freely available.
  • The fundamental attribution error. The fundamental attribution error is a cognitive bias that causes people to underestimate the influence of environment-based situational factors on people’s behavior, and to overestimate the influence of personality-based dispositional factors. For example, the fundamental attribution error can cause someone to assume that if some stranger looks angry, then they must be an angry person in general, even though this person might have been driven to temporary anger by something, such as someone else being rude to them.

Finally, examples of cognitive biases also appear in specific domains:

  • When it comes to entrepreneurship, cognitive biases can cause entrepreneurs to be overly confident and overly optimistic regarding their business ventures.
  • When it comes to medicine, cognitive biases can cause doctors to misdiagnose patients who are displaying symptoms that are atypical for their condition.


Who experiences cognitive biases

Because cognitive biases occur due to the way our basic cognitive system works, every person experiences cognitive biases to some degree, including professional psychologists. Furthermore, cognitive biases occur not only in humans but also in animals, such as bees, pigs, and dogs.


Factors affecting cognitive biases

Various background factors, such as age and culture, can affect the degree to which people experience certain cognitive biases, leading to significant individual variation.

However, the relationship between these background factors and the occurrence of cognitive biases is complex. For example, general cognitive ability is associated with the likelihood that people will experience certain biases, but not all of them. Furthermore, even in cases where there is an association between cognitive ability and the likelihood of biases, the strength of this association varies based on the bias in question.


Why we have cognitive biases

Though there is no single, agreed-upon explanation for all cognitive biases, many theories suggest that cognitive biases are caused by the imperfect way in which we process information and make decisions. In particular, such theories often suggest that cognitive biases occur primarily when we rely on faulty intuitions, or when we fail to conduct a proper reasoning process for some other reason.

Many of the explanations of cognitive biases are situated under dual-process theory, which suggests that we use two main cognitive systems:

  • System 1. This cognitive system is responsible for our intuitive processing, which is fast, automatic, and effortless. Accordingly, processes on this system run in parallel, meaning that it’s possible to engage this system on multiple fronts simultaneously. This system tends to be strongly influenced by emotions. An example of a situation where System 1 is engaged is when we feel pleased because someone laughed at a joke that we told.
  • System 2. This cognitive system is responsible for our conscious reasoning, which is slow, controlled, and effortful. Accordingly, processes in this system run in a serial manner, meaning that this system can only focus on one thing at a time. This system tends to be relatively detached from emotional considerations. An example of a situation where System 2 is engaged is when we try to solve a complex mathematical equation.

A common situation where we display cognitive biases is when we rely on our intuition (System 1) in order to make a decision that requires complex reasoning skills (System 2). For example, in one experiment, students at Princeton University were asked a simple brain teaser:

“A bat and a ball cost $1.10 in total. The bat costs $1 more than the ball. How much does the ball cost?”

Almost anyone who hears this question feels an initial tendency to answer “10 cents”, because the total sum of $1.10 separates naturally into $1 and 10 cents, so that that the answer “10 cents” sounds about right. The problem is that over half the people in the experiment ended up sticking with this initial estimate, leading them to answer this question incorrectly, since the right answer is that the bat costs $1.05, while the ball costs $0.05.

Essentially, what happens here is that most people make an intuitive assessment of the situation using System 1, which gives them a close but incorrect answer to the question.

Some people then use System 2 to assess this initial solution, which generally allows them to realize that it’s incorrect, and which consequently leads them to calculate the correct solution. However, other people fail to engage System 2 properly or at all, which means that they end up relying on the incorrect initial assessment that they got from System 1.

This does not mean that the intuitive assessments provided by System 1 are inherently faulty. Rather, our intuition can be a powerful and accurate tool, and there are many situations where our intuition provides us with the right solution to problems that we encounter. The issue here is that our intuitive system (System 1) is wrong in some situations, which means that it requires proper monitoring by our conscious reasoning system (System 2).

Furthermore, this doesn’t mean that System 2 is always right either. Rather, there are cases where System 2 leads us to make errors in judgment, even though if we conduct a thorough reasoning process.

Overall, based on this framework, cognitive biases occur primarily for two main reasons:

  • System 1 generates a wrong intuitive judgment, and System 2 fails to correct it. This happens when System 2 fails to go into action and properly supervise System 1, or when System 2 goes into action but fails to properly inhibit System 1.
  • System 2 fails to reason correctly. This happens when System 2 leads us to make a wrong judgment, even though it is driven by our analytical reasoning, rather than intuition.

Note that there is some disagreement regarding the exact mechanisms responsible for cognitive biases. Some researchers, for example, argue in favor of dual processes, rather than systems, or in favor of an additional mediating process.

Furthermore, other researchers suggest that different mechanisms may underlie some or all cognitive biases, such as noisy information processing.

Nevertheless, many of these theories share much in common. As such, the outline in this section explains the general type of mechanisms that are often assumed to be responsible for cognitive biases, and is especially helpful for those interested in understanding the concept of cognitive biases from a practical perspective.


Bounded rationality, satisficing, and heuristics

When understanding why people experience cognitive biases, there are several important concepts that are helpful to understand, beyond the ones discussed so far:

  • Bounded rationality. Bounded rationality is the idea that our decision-making ability is constrained by the limitations of our cognitive systems, and depends on the type of information that we have to process as well as on the amount of time that we have in order to process it. This means that when we try to solve a problem, we often end up reaching a solution that is different from the one we would reach if our cognitive systems were perfect, or from the one that we would reach if we had more time to consider the problem. Cognitive biases are a notable feature of our bounded rationality.
  • Satisficing. Satisficing, which is a blend of sufficing and satisfying, represents the willingness to pass judgments and make decisions that are good enough given the circumstances, rather than perfect. It is therefore contrasted with maximizing, which is the preference for finding the absolute best course of action. Satisficing can lead us to experience a variety of cognitive biases.
  • Heuristics. Heuristics are mental shortcuts that help us quickly reach a ‘good enough’ solution to our problems. For example, if we are asked how many apples there are in a basket, then instead of counting all the apples individually, we can apply a heuristic, and see how much room 3 apples take, and then estimate how many groups of 3 apples there are in the basket. Heuristics, which are associated primarily with System 1, are generally seen as a form of satisficing, and stand at the core of many cognitive biases. This includes, for example, biases such as the availability heuristic and the representativeness heuristic.


Additional information about our cognitive system

When understanding our cognitive system, in the context of cognitive biases, there are two additional concepts that can be useful to understand.

First, which System is engaged at any given time depends on factors such as a person’s skill level and the circumstances. For example, skilled drivers are often able to talk while driving, which indicates that for them, driving is intuitive, since it’s difficult to perform two System 2 processes simultaneously, as we saw above. However, even the most experienced drivers will generally struggle to talk if they’re driving in rough conditions, which require their full attention.

Second, our perception system, which is responsible for our ability to perceive input, is considered to be distinct from our two other cognitive systems (System 1 and System 2). Though there are some similarities between our perception system and System 1, since they both consist primarily of automatic subconscious processes that run in parallel to each other, there are some key differences between them:

  • Our perception is relatively neutral, while System 1 is influenced by various emotional and social considerations.
  • Our perception is evoked by direct stimulus only, while System 1 can be evoked by things such as thoughts.
  • Our perception is limited to perceptual representations, while System 1 can generate abstract representations.
  • Our perception is limited to stimuli that we encounter in the present, while System 1 can also deal with information that relates to the past or the future.

Essentially, our perceptual system provides us with information that is fed into System 1, in order to form intuitive impressions. Then, these impressions undergo deliberate operations of reasoning by System 2, in order to form conscious judgments.


Types of cognitive biases

Various criteria have been used to categorize the different types of cognitive biases, and there is no single, agreed-upon scheme. However, biases are often categorized based on the aspect of people’s judgment and decision-making that they affect, as well as their reason for doing so. Based on this criterion, the main types of biases are often the following:

  • Calculation biases. These are biases that affect the way in which we calculate things such as probabilities or values. For example, the gambler’s fallacy is a cognitive bias that causes people to mistakenly believe that if something happens more frequently than normal during a given time period, then it will happen less frequently in the future. This occurs because people believe that a short sequence of random independent events should be representative of a longer sequence of such events.
  • Information biases. These are biases that affect the way in which we acquire and process information. For example, the contrast effect is a cognitive bias that distorts our perception of something when we compare it to something else, by enhancing the differences between them. The main reason why people experience this bias is that the process which we use to process and evaluate information often relies on comparisons, regardless of whether or not those comparisons are to our benefit.
  • Belief biases. These are biases that affect the way in which we form and modify our beliefs. For example, the false-consensus effect is a cognitive bias that causes people to overestimate the degree to which their beliefs, values, characteristics, and behaviors are shared by others. Essentially, this means that the false consensus effect leads people to assume that others think and act in the same way that they do, even when that isn’t the case.
  • Memory biases. These are biases that affect the way our memory works. For example, rosy retrospection is a cognitive bias that causes people to remember past events as being more positive than they were in reality. This occurs because when people experience a certain event, they tend to have both positive and negative thoughts, but as time passes they are more likely to forget their negative thoughts than their positive ones.
  • Social biases. These are biases that affect our social perception and behavior. For example, the spotlight effect is a cognitive bias that causes people to think that they are being observed and noticed by others more than they actually are. This occurs because people naturally see everything from their own point of view, so they struggle to accurately judge how they look through other people’s eyes.

Some biases can into multiple categories.

For example, the bandwagon effect is a cognitive bias that causes people to do something because they believe that other people are doing the same thing. It is a social bias, but it can affect people in various domains, such as when it comes to their belief or their memory.

Similarly, the confirmation bias, which is a cognitive bias that causes people to search for, favor, interpret, and recall information in a way that confirms their preexisting beliefs. This is an information bias, but it can affect the way people shape their beliefs or remember or information.


Hot and cold biases

A criterion that is sometimes used to categorize cognitive biases is the distinction between hot and cold biases:

  • Hot biases are biases that are motivated by emotional considerations, such as our desire to have a positive self-image. For example, the self-serving bias is a cognitive bias that causes people to take credit for their successes and positive behaviors by attributing them to dispositional factors, and to deny responsibility for failures and negative behaviors by attributing them to situational factors. This bias occurs due to people’s need to enhance their self-esteem, and is strongly influenced by various emotional considerations.
  • Cold biases are biases that occur due to emotionally-neutral processes, such as limitations of our cognitive capacity. For example, the telescoping effect is a cognitive bias that causes people to perceive past events as being more recent than they are, and recent events as being more remote. This bias occurs due to the way our memory works, and isn’t generally affected by any emotional considerations.

Accordingly, the difference between hot and cold biases is that hot biases are emotionally motivated, whereas cold biases are not.

This distinction is imperfect, since it is sometimes difficult to establish whether a certain bias is hot or cold, either in general or under particular circumstances.

For example, the hindsight bias causes people to overestimate how predictable a past event was, once they already know its outcome. The hindsight bias can occur due to “hot” reasons, such as when a person wants to believe that they were smart enough to have predicted what was going to happen. However, the hindsight bias can also occur due to “cold” reasons, such as when a person struggles to ignore information that they have available to them in the present, when trying to assess their mindset in the past.

Nevertheless, despite the limitations of the hot/cold distinction when it comes to cognitive biases, it can be useful in some cases, such as when a certain bias is clearly “hot” or clearly “cold”.


Cognitive debiasing

The problem with cognitive biases

As we saw so far, cognitive biases can be problematic, because they distort our thinking and can cause us to make bad decisions.

For example, the ostrich effect is a cognitive bias that causes people to avoid information that they perceive as potentially unpleasant. This means that this bias can cause you to avoid acquiring important information, such as information on how to deal with a medical condition that you have. Being able to mitigate the ostrich effect is therefore important, since it can prompt you to acquire useful information that you would otherwise avoid.

Accordingly, learning how to debias can be beneficial in many situations, both when it comes to helping yourself thinking more clearly, as well as when it comes to helping others.


Reducing and avoiding cognitive biases

As we saw earlier, cognitive biases occur as a result of two main issues with our cognitive system:

  • Failure of System 1 (our intuitive system) to generate correct intuitions together with a failure of System 2 (our reasoning system) to monitor and inhibit System 1.
  • Failure of System 2 to conduct a proper reasoning process.

Based on this, there are three main things that you can do in order to mitigate cognitive biases:

  • Help System 1 generate better intuitions. You can do this in various ways, such as by practicing the formation of intuitive impressions, while providing System 1 with feedback that helps it improve in the long-term.
  • Help System 2 monitor and inhibit System 1 better. You can do this in various ways, such as by improving your decision-making environment, to help System 2 inhibit System 1.
  • Help System 2 conduct a proper reasoning process. You can do this in various ways, such as by slowing down your reasoning process, to give System 2 more time to carry it out properly.

Most commonly, to avoid and reduce cognitive biases, you will need to implement various debiasing techniques, which are a type of metacognitive strategies that help you regulate your cognition.

Different debiasing techniques are applicable in different circumstances.

Some techniques are relatively simple and universal; this includes, for example, increasing your awareness of relevant biases. Other techniques are more specific; this includes, for example, creating psychological self-distance in order to mitigate the egocentric bias, which is a cognitive bias that causes people to rely too heavily on their own point of view when they examine events in their life or when they try to see things from other people’s perspective.

Furthermore, the effectiveness of debiasing techniques varies based on the bias in question. For example, consider the anchoring bias, which causes people to over-rely on an initial piece of information during subsequent judgment. Debiasing is generally much less effective when the anchoring is based on an explicit comparison between the anchor and the subsequent piece of information, meaning that it’s harder to reduce this bias when the comparison to the anchor is one that the person was explicitly asked to make.

Note that because the use of these debiasing techniques requires conscious efforts, they primarily have to do with improving the functioning of System 2. However, the application of these techniques can become easier over time, sometimes to the degree where they can also influence your intuition, though they can be effective even at an early stage.

Overall, this section describes the basic principles behind cognitive debiasing. If you would like to learn more about how to debias effectively, you should read the dedicated article on the topic.


Additional information

Cognitive biases aren’t always bad

Though cognitive biases are examples of irrationality, they do not always affect us in a negative manner. Rather, cognitive biases can sometimes influence our thought process in a positive way, that helps us make optimal decisions.

For example, the pessimism bias is a cognitive bias that causes people to overestimate the likelihood of negative things and underestimate the likelihood of positive things, especially when it comes to assuming that future events will have a bad outcome.

This bias can negatively impact people in some cases, such as when it causes them to avoid making an effort, by leading them to assume that they will inevitably fail. However, the pessimism bias can also positively impact people in some cases, such as when it causes people to properly prepare for the future, by leading them to believe that they are likely to encounter difficulties.

Furthermore, many biases serve as useful mental shortcuts, that can help us simplify complex problems and make decisions quickly, which can be beneficial in many cases, even if it means that we won’t make the best possible decision in every situation.

Finally, cognitive biases can also be beneficial in various other ways. From an individual perspective, for example, cognitive biases can help people make optimal decisions when uncertainty is involved. Similarly, from a group perspective, cognitive biases can encourage people to help each other.

Accordingly, from an evolutionary perspective, cognitive biases are sometimes viewed as design features rather than design flaws, meaning that they are viewed as adaptive behavior, that can be beneficial in many cases.

Overall, though cognitive biases can negatively impact people in various ways, they can also be beneficial in some cases. This is true both on an individual scale, such as when biases encourage people to prepare for the future, and on a group scale, such as when biases encourage cooperation.

As such, it’s important to understand that cognitive biases can sometimes help you to make optimal decisions, even if they distort your view of the situation. At the same time, however, it’s still important to be aware of them, so that you can evaluate their effect, and determine whether or not you will benefit from reducing their influence.

Note: when discussing the potential value of cognitive biases, some researchers draw a distinction between cognitive biases as an “inaccurate view of the world” and outcome biases as “a departure from rational behavior”. Under this distinction, a cognitive bias “might produce rational behaviour or might result in an outcome bias”.


The difference between cognitive biases and logical fallacies

While cognitive biases and logical fallacies are similar, they represent two distinctly different things:

  • Cognitive biases involve systematic errors in cognition, and are therefore a psychological concept.
  • Logical fallacies involve flawed patterns of argumentation, and are therefore a philosophical concept.

Cognitive biases often occur at a more basic level of thinking, particularly when they’re rooted in people’s intuition, and they can lead to the use of various logical fallacies.

For example, consider the appeal to nature, which is a logical fallacy where something is claimed to be good because it’s perceived as natural, or bad because it’s perceived as unnatural. This fallacy can sometimes be rooted in certain cognitive biases, that cause people to instinctively prefer things that they perceive as being natural.

Furthermore, in some cases, certain logical fallacies, and particularly those that are employed for rhetorical purposes, can take advantage of people’s cognitive biases.

For example, consider slippery slope arguments, which are argument that suggests that a certain initial action could lead to a chain of events with a relatively extreme result, or that if we treat one case a certain way then we will have to treat more extreme cases the same way too. Someone using such arguments might take advantage of people’s pessimism bias, in order to make them believe that the conclusion of a fallacious slippery slope argument is more likely than is actually the case.

However, this doesn’t mean that the use of logical fallacies is always associated with related cognitive biases.

For example, consider strawman arguments, which are fallacious arguments that distort an opposing stance in order to make it easier to attack. While someone might use a strawman argument because they misunderstand their opponent’s argument due to some cognitive bias, it’s also entirely possible to use such arguments consciously, while being aware that you are doing so, and without being driven to it by any bias or trying to get someone else to experience a cognitive bias either.

Overall, the main distinction between cognitive biases and logical fallacies is that biases are a psychological concept, that has to do with cognition, while fallacies are a philosophical concept, that has to do with argumentation. Cognitive biases are sometimes associated with certain fallacies, such as when a cognitive bias leads to the use of a fallacy, or when a fallacy’s rhetorical effectiveness relies on an underlying bias, but each of these phenomena can appear on its own.

Note: logical fallacies are often described as flawed patterns of reasoning, rather than argumentation. The term ‘argumentation’ is used here to emphasize that fallacies have to do with a different type of reasoning than cognitive biases.


The history of cognitive biases

Though cognitive biases have affected humans and other animals from an early stage of our development, this concept was formalized and popularized in the early 1970s by two researchers, Daniel Kahneman and Amos Tversky, in a series of papers on the topic. These initial papers, which deal with systematic irrationality in general and with the concept of biases in particular, include the following:

The two earlier papers served primarily to introduce the concept of heuristics under the framework described by Kahneman and Tversky, while the 1974 paper became the most-cited article on the topic, and introduced cognitive biases as we know them today.

Kahneman went on to win the 2002 Nobel Prize in Economics for his joint work with Tversky, who died in 1996.

To learn more about the history of cognitive biases, you should read Kahneman’s famous book on the topic: “Thinking, Fast and Slow“. If interested, you can also read the book written about Kahneman and Tversky: “The Undoing Project: A Friendship That Changed Our Minds“, or the review of the book published in The New Yorker.


Summary and conclusions

  • A cognitive bias is a systematic pattern of deviation from rationality, which occurs due to the way our cognitive system works.
  • Cognitive biases cause us to be irrational in the way we search for, evaluate, interpret, judge, use, and remember information, as well as in the way we make decisions.
  • Though various factors affect the way in which people experience cognitive biases, everyone experiences biases to some degree, including trained psychologists.
  • Many different theories have been proposed to explain why we experience biases; a notable one is dual-process theory, which generally suggests that we experience biases as a result of faulty intuitions that our analytical system fails to correct, or as a reason of our analytical system failing to conduct a proper reasoning process.
  • Cognitive biases can often lead to problems with our judgment and decision-making, but it is possible to reduce and avoid them in various ways, including, most notably, through the use of general and specialized debiasing techniques.

If you want to read more about this topic, you want to learn more about the concept of cognitive biases, the best book on the topic is “Thinking, Fast and Slow“, by Daniel Kahneman, the Nobel laureate who first described the concept.

In addition, two other recommended books are “Predictably Irrational” and “The Art of Thinking Clearly“, which will help you learn more about common biases and patterns of irrationality that people display.