- Clearer Thinking Team
A List of Common Cognitive Biases (With Examples)
Updated: 5 days ago
Cognitive biases are patterns of thinking that distort or skew information processing, often leading to errors. These biases often occur when we make a quick decision using intuition or heuristics, which are simple rules or shortcuts that we use to make decisions and solve problems quickly without necessarily considering all available information.
In the early 1970s, cognitive psychologists Amos Tversky and Daniel Kahneman introduced the term 'cognitive bias' after studying perceptual bias in problem-solving that used heuristics. Since then, cognitive psychology has demonstrated that cognitive biases occur systematically and universally and are involuntary: no one is totally immune to them. But it can help to identify them.
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List of the most common cognitive biases
Here, we list the most common cognitive biases. We strongly recommend reading the second part of this article, where we answer popular questions and clarify common misunderstandings about the topic.
The Ambiguity Effect is a cognitive bias whereby people who are faced with a decision tend to pick an option for which they know the probability of a good outcome, rather than an option for which the probability of a good outcome is unknown or ambiguous. Even if the known probability is low and picking it isn't the best strategy.
"I know that if I pick Door 1, I have a 15% chance of winning a decent prize. But if I pick Door 2, I don't know what the odds of winning are or how good the prize would be. I guess I'll pick Door 1!"
Anchoring Bias occurs when a person's expectation about one thing is affected by something they saw, heard, or thought before. In other words, it occurs when a person relies too heavily on a specific piece of information to govern their thought process.
Attention Bias occurs when some information or evidence holds a disproportionate amount of a person's attention because of that person's environment or history.
Example You might only focus on what could go wrong in a situation, less often considering what could go right or how things are likely to go. You might worry a lot, reducing your overall quality of life and preoccupying your mind with unnecessary worries.
The Availability Bias occurs when someone's prediction about an event's frequency or probability is unduly influenced by how easily they can think of examples of that event.
Example Ask yourself "Are there more English words that start with 'k' or that have 'k' as the third letter?" If you (like most people) guessed that there are more words that start with 'k', you were probably influenced by the fact that it's much easier to think of examples of those words. However, there are in fact more words with 'k' as the third letter!
We have a whole mini-course about combating this bias, which you can take free, here!
Bias Blind Spot
A Bias Blind Spot is a tendency to see oneself as being less susceptible to biases (such as those listed in this article) than others in the population.
Choice-Supportive Bias is a cognitive bias whereby someone who has chosen between different options later remembers the option that they chose as having more positive attributes than it did at the time (while they remember options they did not choose as having more negative attributes than they'd had at the time).
Example Someone who chose to undertake an expensive and time-consuming course to gain a particular skill might retrospectively remember many positive aspects of the course they chose (even if these did not enter into their decision at the time), and remember the alternative options as being worse than they were (e.g., they might overestimate how unpleasant or difficult it would have been to learn the skill another way, to gain more work experience while still learning the skill, and so on).
Confirmation Bias refers to a tendency for people to favor information that confirms their preconceptions or hypotheses (even if the information isn't true).
Example The spread of false news stories on social media is a great example of this type of bias. People are less likely to fact check stories that confirm their existing beliefs, and so share dubious stories without thinking carefully about them.
The Denomination Effect is a cognitive bias whereby people tend to be more likely to spend a given amount of money if it is composed of smaller individual sums than if it is composed of larger individual sums.
Imagine you pass a bakery. You might be more likely to buy 5 items that cost $1 each than 1 item that costs $5.
Hindsight Bias refers to a tendency to perceive past events as being more predictable than they were before they took place.
You might exaggerate by saying you “had a bad feeling all along” when a decision you made didn't work out, when in fact you only experienced ordinary nervousness about making a decision.
Optimism Bias is the tendency to be unduly optimistic about the probability of future events, overestimating the probability of positive ones while underestimating the probability of negative ones.
You might say "I know there are risks and logistical problems involved in getting everyone vaccinated against this new disease, but they probably won't be that big of a deal."
Motivated reasoning occurs when you are disposed to interpret new evidence in ways that support your existing beliefs, even when that evidence doesn't really.
Someone reads an academic study containing data supporting the argument that a specific policy might help to reduce crime. However, since they don't support this policy, they construct an argument using the same data from the study, suggesting that it might increase crime.
Frequently Asked Questions (FAQ) about cognitive biases
What are the types of bias?
There are three main types of bias.
1. Explicit biases are prejudiced beliefs regarding a group of people or ways of living. Racism, sexism, religious intolerance, and LGBTQ-phobias are examples of explicit biases.
2. Implicit biases are unconscious beliefs that lead people to form opinions or judgments, often without being fully aware they hold the unconscious beliefs.
3. Cognitive biases differ from explicit and implicit biases: they are a group of systematic patterns in how our beliefs, judgments, and actions differ from what they would if we were completely rational.
How many cognitive biases are there?
There is no consensus among academics regarding how many cognitive biases exist. Some have found ~40, others find >100, and Wikipedia lists over 180.
What are the common causes of cognitive bias?
As we’ve seen above, cognitive biases often appear when one is faced with a decision and has limited resources (such as time, understanding, and cognitive capacity).
For instance, when buying a banana, you can't consider every single possible other use of that money to determine whether a banana is truly the single best use. You are limited in both how much time you have to think and how much total cognitive capacity you have. Heuristics are an effective way of reasoning in these situations because they require fewer resources than careful thinking. However, your decisions may be more swayed by cognitive biases when you have to act fast with little information.
Of course, it's plausible that even with plenty of time and cognitive resources, people might still be prone to cognitive biases. For instance, there might be survival value for such bias as attention bias and the ambiguity effect.
Is cognitive bias a good or bad thing?
Cognitive biases are not good or bad in themselves. They are an unavoidable effect of not having infinite intelligence and infinite time to think. Sometimes they produce good outcomes, and sometimes they produce bad.
Good outcomes can occur when they help us to make optimal decisions despite uncertainty, such as when accepting a challenge at work due to optimism bias.
Bad outcomes can occur, for instance, when you favor the good aspects of a candidate's reputation because you believe he is the best fit.
How do you identify cognitive biases?
Just knowing that there are such things as cognitive biases is a great first step to identifying them in yourself. Once you’ve done that, it can be helpful to get to know the most common cognitive biases (such as the ones presented above) so that you can look out for them in your own thinking.
Can you avoid cognitive bias?
Yes and no. It is possible to reduce the influence of cognitive biases on your thinking (and this can be very beneficial!), but it's not possible to completely remove all of your cognitive biases.
How do you overcome cognitive biases?
Unfortunately, it’s impossible to overcome all of your cognitive biases completely. However, that doesn’t mean you can’t do anything. A good first step on the path to getting your cognitive biases under control is familiarizing yourself with them - here is one of our interactive tools that might help!
However, just knowing about your cognitive biases isn’t enough. You need to take action! Here are some practical steps we recommend:
Using tools to achieve your task is helpful, e.g., keeping track of information, developing evaluation criteria, and scoring data. Even the simplest checklist is a great way to deal with peak-end rule and selective perception bias, for instance.
Biases such as overconfidence, confirmation bias, and the illusion of control can be reduced or avoided by having multiple points of view. Surrounding yourself and listening to people with diverse experiences, systems of beliefs, and expertise reduces the chances of falling into one of the said biases. This is also true for the source of information: it is less likely that you fall into a cognitive bias if you look for other data sources and conflict.
Another strategy recommended by researchers who studied cognitive biases in physicians, is to consciously consider the options you dismissed at first, so you can reach a more mindful answer.
What is a cognitive vs. an emotional bias?
Emotional biases can be considered a subcategory of cognitive biases. What separates them from other cognitive biases is that they are based on emotions such as anger, disgust, fear, happiness, sadness, and surprise.
Emotional biases are linked to emotional dispositions (commonly known as ‘temperament’). Different emotional dispositions may even lead to different emotional reactions to the same occurrence of events.
Acknowledging emotional biases helps us explain optimism and pessimism biases.
How do cognitive biases affect critical thinking?
Cognitive biases interfere with impartiality, and they can negatively affect critical thinking in a myriad of different ways. Here are several:
Motivated reasoning leads us to underestimate the arguments for conclusions we don’t believe in and overestimate the arguments for conclusions we want to believe;
Availability bias messes with our critical thinking because it leads us to asses risk by how readily examples come to mind;
And remember, we are also prone to blind spot bias, meaning that we are less likely to identify biases in our own judgment than in other people's.
How do cognitive biases affect decision-making?
Cognitive biases affect decision-making in at least two ways: they help decision-making by speeding it up and cutting corners when we have limited time or cognitive power, but they also hinder decision-making by being prone to errors.
Is gender a factor for cognitive biases?
Research has shown some correlation between gender and specific biases. For instance, researchers found that male investors tend to show overconfidence and optimism biases, while female investors tend to exhibit anchoring and hindsight biases. (The research makes no claims about what causes such gendered differences - e.g., socialization or biology.)
Are gender stereotypes cognitive bias?
Gender stereotypes are explicit biases, which means they are not cognitive biases. However, there are many cognitive biases that involve gender stereotypes. For example, masculine bias is the tendency to assume a person is a male after hearing gender-neutral information about them, and the tendency to use gender as a description only when describing women.
Gender stereotypes are also a sign of binary thinking.
Do cognitive biases cause depression?
Research has shown some cognitive biases are correlated with depression. This is the case for negative interpretation bias (the tendency to interpret ambiguous scenarios as negative) and pessimistic biases, which lead people to predict future situations as negative.
Cognitive behavioral therapy is based on the assumption that individuals with depression have negative cognitive biases. Evidence for and against this assumption is not conclusive.
Are cognitive biases scientific (is their existence scientifically proven)?
Yes. They have been studied since the early 1970s by cognitive psychologists, sociologists, and behavioral economists. There is even research on the presence of cognitive biases in scientific contexts and academic publications. Nobody is immune!
Do scientists exhibit cognitive biases?
Just like every other human being, scientists can exhibit cognitive biases. It may be overconfidence bias or selection bias, for example. This has been researched as it relates to the replication crisis social psychology faces today.
Are cognitive biases learned? Or are we born with cognitive biases?
Both. Our brains have evolved to be prone to all sorts of cognitive biases because those biases have been highly effective in decision-making processes. But the details of many specific cognitive biases are learned as we move through the world. For example, humans have evolved a tendency to engage in motivated reasoning, but which conclusions motivate your reasoning is something you aren’t born with and must be learned.
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