To submit requests for assistance, or provide feedback regarding accessibility, please contact

Science & Tech

How to Identify Bias: 14 Types of Bias

Written by MasterClass

Last updated: Nov 9, 2020 • 5 min read

Understanding your biases and assumptions is crucial to clear thinking and scientific literacy. All of us, no matter our education, intellectual commitment, or good intentions, are susceptible to biases.



Neil deGrasse Tyson Teaches Scientific Thinking and CommunicationNeil deGrasse Tyson Teaches Scientific Thinking and Communication

Renowned astrophysicist Neil deGrasse Tyson teaches you how to find objective truths and shares his tools for communicating what you discover.

Learn More

What Is Bias?

A bias is a strong, preconceived notion of someone or something, based on information we have, perceive to have, or lack. It is a subjective way of thinking that originates from an individual’s own perception or points of view. There are different types of bias people experience that influence and affect the way we think, behave, and perceive others.

14 Types of Bias

When it comes to human behavior, there are many common types of bias we have that can influence the way we think and act in our everyday lives.

  1. Confirmation bias. This type of bias refers to the tendency to seek out information that supports something you already believe, and is a particularly pernicious subset of cognitive bias—you remember the hits and forget the misses, which is a flaw in human reasoning. People will cue into things that matter to them, and dismiss the things that don’t, which can lead to the “ostrich effect” (named so because ostriches bury their heads in the sand), where a subject seeks to avoid information that may disprove their original point.
  2. The Dunning-Kruger Effect. This particular bias refers to how people perceive a concept or event to be simplistic just because their knowledge about it may be simple or lacking—the less you know about something, the less complicated it may appear. However, this form of bias limits curiosity—people don’t feel the need to further explore a concept, because it seems simplistic to them. This bias can also lead people to think they are smarter than they actually are because they have reduced a complex idea to a simplistic understanding.
  3. Cultural bias. Cultural bias, also known as implicit bias, involves those who perceive other cultures as being abnormal, outlying, or exotic, simply based on a comparison to their own culture. Also known as implicit social cognition, this bias attributes the traits and behaviors of an individual to a larger group of people. Implicit bias creates attitudes or stereotypes that can affect or influence our decisions in an unconscious way. This unconscious bias affects many people because they are unaware of the origins of their baseline of thinking.
  4. In-group bias. This type of bias refers to how people are more likely to support or believe someone within their own social group than an outsider. This bias tends to remove objectivity from any sort of selection or hiring process, as individuals tend to favor those who they personally know and want to help.
  5. Decline bias. The decline bias refers to the tendency to compare the past to the present, leading to the decision that things are worse, or becoming worse in comparison to the past, simply because change is occurring.
  6. Optimism or pessimism bias. This bias refers to how individuals are more likely to estimate a positive outcome if they are in a good mood, and a negative outcome if they are in a bad mood.
  7. Self-serving bias. A self-serving bias is an assumption that good things happen to us when we’ve done all the right things, but bad things happen to us because of circumstances outside our control or things other people purport. This bias results in a tendency to blame outside circumstances for bad situations rather than taking personal responsibility.
  8. Information bias. Information bias is a type of cognitive bias that refers to the idea that amassing more information will aid in better decision-making, even if that extra information is irrelevant to the actual subject at hand.
  9. Selection bias. This bias refers to the way individuals notice things more when something has happened to make us notice that particular thing more—like when you buy a car and suddenly notice more models of that car on the road. The car has simply become part of the individual’s observations, so they tend to observe it more elsewhere (also known as observational selection bias).
  10. Availability bias. Also known as the availability heuristic, this bias refers to the tendency to use the information we can quickly recall when evaluating a topic or idea—even if this information is not the best representation of the topic or idea. Using this mental shortcut, we deem the information we can most easily recall as valid and ignore alternative solutions or opinions.
  11. Fundamental attribution error. This bias refers to an individual’s tendency to attribute someone’s particular behaviors to existing, unfounded stereotypes, while attributing their own similar behavior to external factors. For instance, when someone on your team is late to an important meeting, you may assume that they are lazy or lacking motivation without considering internal and external factors like an illness or traffic accident that led to the tardiness. However, when you are running late because of a flat tire, you expect others to attribute the error to the external factor (flat tire) rather than your personal behavior.
  12. Hindsight bias. Hindsight bias, also known as the knew-it-all-along effect, is when people perceive events to be more predictable after they happen. With this bias, people overestimate their ability to predict an outcome beforehand, even though the information they had at the time would not have led them to the correct outcome. This type of bias happens often in sports and world affairs. Hindsight bias can lead to overconfidence in one’s ability to predict future outcomes.
  13. Anchoring bias. The anchoring bias, or focalism, pertains to those who rely too heavily on the first piece of information they receive—an “anchoring” fact— and base all subsequent judgments or opinions on this fact. For instance, if you tell someone a picture frame costs $20 and they go to a store that sells it for $15, their anchoring bias will lead them to perceive the $15 frame as a bargain, even though it may be on sale at a different store for $10. With anchoring bias, the initial price of the frame will influence a person’s perception of its value.
  14. Observer bias. The observer bias occurs when someone’s evaluation of another person is influenced by their own inherent cognitive biases. Observers, like researchers or scientists, may assess the outcome of an experiment differently depending on their existing evaluations of the current subject. Subsequently, the subject that is under observation may alter their behavior if they know they are being observed. Double-blind studies are often implemented to overcome observer bias.
Neil deGrasse Tyson Teaches Scientific Thinking and Communication
Neil deGrasse Tyson Teaches Scientific Thinking and Communication
Dr. Jane Goodall Teaches Conservation
Chris Hadfield Teaches Space Exploration

Learn More

Get the MasterClass Annual Membership for exclusive access to video lessons taught by business and science luminaries, including Neil deGrasse Tyson, Chris Hadfield, Jane Goodall, and more.