What is cognitive bias?

Cognitive bias is a systematic error in thinking—a shortcut your brain takes while processing new information, moving data through a filter of preferences and personal experiences. Psychologists Amos Tversky and Daniel Kahneman introduced the concept in 1972.

Psychologists see cognitive bias as a coping mechanism: simplifying new data lets your brain process it faster. On the surface, it works well, but this subconscious act can cause incorrect judgments and interpretations—particularly during the process.

Here’s how cognitive biases work, common types with examples, and ways to overcome them.

Cognitive biases simplified

When your brain discovers new information, it can be hard to process it along with everything else it has to do. Attention and brainpower are finite resources. That’s why our brains look for easy shortcuts, which is when cognitive biases slip in.

Your brain does some guesswork to make new things easier to process. It relies on your opinions, past experiences, and your general view of the world. It’s easy to see why processing information through these lenses can lead to falsely interpreting new data.

For example, if you’ve had a bad experience with a dog, your brain may jump to all dogs being scary and dangerous. Another common one is “all politicians are the same”—a generalization that saves the mental effort of weighing each one individually.

These are examples of a cognitive bias called stereotyping. Generalizations like these make the world easier to process, but they cause us to miss the nuance.

Types of cognitive bias with examples

There are many types of cognitive bias. Here are a few common examples:

Actor-observer bias

The actor-observer bias is when you blame outside forces for your actions while holding other people responsible for theirs. It’s a difference in how we see ourselves and others.

An example of the actor-observer bias is saying you failed a test because it had trick questions, but others failed because they’re incompetent.

Anchoring bias

Anchoring bias is becoming too attached to the first piece of information you encounter on a topic. If you’re unwavering in your views even in the face of fresh data, that’s anchoring. It gets in the way of decisions, and even your mood can influence it.

Examples of anchoring bias appear everywhere, from families to medicine.

Maybe you’ve argued with older generations about the housing market and the impossibility of buying a home nowadays, but they’re adamant it’s a piece of cake. They may be dealing with anchoring bias, believing their experience is the same as yours. Unfortunately for you, it isn’t.

Another example is a doctor’s first impression of a new patient. If the patient is overweight, the doctor may immediately judge them based on this and blame their symptoms on needing to lose weight. This bias can cause the doctor to overlook the real issue—which can be dangerous—and may discourage the patient from seeking medical help in the future.

Confirmation bias

If you mostly listen to information that confirms your beliefs, that’s . This is where the echo chamber reinforces your views and closes your mind to other perspectives.

Confirmation bias examples include:

Refusing to hear the opposing side
Only ‘liking’ or ‘following’ those with the same views on social media
Choosing news outlets that support your mindset
Ignoring facts that don’t align with your views—“fake news” may ring a bell

Availability heuristic

The means you tend to estimate probability by how many examples you can think of. It’s a bias toward what’s most readily available in your mind.

An example is thinking that plane crashes are common, leading many people to fear flying. Crashes dominate the news, but we don’t hear about the roughly 100,000 flights that land safely every day—commercial flying remains one of the safest ways to travel.

Self-serving bias

You fall into the self-serving bias trap when you blame outside influences for problems but take credit for your successes.

Imagine you’re taking your driving test. You pass the second time, thanks to your fantastic driving. But the first fail was the examiner’s fault—they tripped you up. It definitely wasn’t because you ran a red light. Definitely not.

Halo effect

First impressions matter, and the confirms that. When we meet a physically attractive or charming person, we’re more likely to think they’re a good person with other positive traits. This initial positive impression can make it tricky to accept opposing information.

For example, a charismatic politician appears on TV, and you think they’re an excellent candidate because of your positive first impression. If the politician gets caught up in an awful scandal, you may insist they’re a good person solely based on their charisma.

Optimism bias

Optimism bias is when you overestimate the chances of something good happening. It’s also very common to underestimate the chances that something bad will happen.

Two everyday examples are smoking and divorce. Smokers know other people develop cancer from smoking but assume it won’t happen to them. Couples marry confident the divorce statistics don’t apply to them.

False consensus effect

Believing everyone shares your mindset, beliefs, attitude, and values is the . This bias happens for many reasons, including growing up around similar views and surrounding yourself with people of the same mindset.

An example is someone who believes in Bigfoot. They may think they’re in the majority, and only a few don’t believe.

Signs of cognitive bias

Look out for these signs of cognitive bias:

Only listening to information agreeing with your opinion, creating an echo chamber
Blaming others for your bad luck
Taking credit for your achievements while believing others rely on luck
Believing you are always correct
Believing everyone shares your opinion or belief
Thinking you’re an expert in a topic you know little about

Causes of cognitive bias

Several things can cause cognitive bias, like:

Having limited resources and not being able to access different viewpoints
Only hearing one viewpoint most of your life
Personal motivations: Sometimes it’s beneficial to think in a certain way
Having a short attention span where you can’t evaluate details as thoroughly
Living in a community with a majority view where opposing opinions are considered dangerous, offensive, or disrespectful

Ways to overcome cognitive bias

Cognitive bias affects most of us, but we can start defeating it in a few steps:

Consider the current situation

Are current circumstances influencing your thoughts and feelings? Are you experiencing the bandwagon effect and agreeing because everyone else is?

Consider the forces surrounding you and take a step back. What do you think and believe outside this bubble?

Acknowledge your bias

The best way to overcome bias is to recognize it exists. Once you know where the bias is, you can be more careful in your decisions and judgments.

Stay curious

Curiosity means asking questions and exploring information instead of taking things at face value. That’ll widen your worldview and help you beat the bias.

Think about the past

Another way to overcome cognitive bias is to reflect on past mistakes and bad situations and find any patterns. Do you ignore red flags until they become problems?

And then there’s how we form biases. If you grew up in a household with strong opinions, are you still carrying those with you, even with opposing evidence?

See it from all sides

No matter how sure you are of your viewpoint, debate it from the opposite side. Pushing yourself to see all angles of the issue can boost your empathy and remove cognitive bias.

Find refuting evidence

Actively looking for hard evidence that goes against your views can help you find the truth, even if it makes you uncomfortable. Opening up this line of thinking makes you much more open-minded, lowering your cognitive bias.