The human brain is pretty tricky: While we think we know things, there’s a whole list of cognitive biases that can be gumming up the works. We’ve found 50 types of cognitive bias that come up nearly every day, in petty Facebook arguments, in horoscopes, and on the global stage. Along with their definitions, these are real-life examples of cognitive bias, from the subtle groupthink sabotaging your management meetings to the pull of anchoring making you spend way too much money at a store during a sale. Knowing about this list of biases can help you make more informed decisions and realize when you’re way off the mark.
What Is Cognitive Bias?
Let’s start off with a basic cognitive bias definition: It is a systematic error in cognitive processes (like thinking, perceiving, and memory) diverging from rationality, which can affect judgments. If we think of the human brain as a computer, cognitive bias basically is an error in the code, making us perceive the input differently or come up with an output that’s illogical.
But there are other types of bias as well that aren’t necessarily cognitive; for example, there’s the theory of social proofing, which is one of the more popular social psychological biases. Also, there can be cognitive theories that aren’t necessarily considered biases, or rather, they’re more like a network of common biases tangled together, like cognitive dissonance, which causes mental discomfort when we hold conflicting ideas or beliefs in our minds. Then, there’s the world-famous placebo effect, which can actually result in physiological changes.
Let’s go into some common cognitive bias examples to really see how they work!
50 Types of Common Cognitive Biases
- Fundamental Attribution Error: We judge others on their personality or fundamental character, but we judge ourselves on the situation.
- Self-Serving Bias: Our failures are situational, but our successes are our responsibility.
- In-Group Favoritism: We favor people who are in our in-group as opposed to an out-group.
- Bandwagon Effect: Ideas, fads, and beliefs grow as more people adopt them.
- Groupthink: Due to a desire for conformity and harmony in the group, we make irrational decisions, often to minimize conflict.
- Halo Effect: If you see a person as having a positive trait, that positive impression will spill over into their other traits. (This also works for negative traits.)
- Moral Luck: Better moral standing happens due to a positive outcome; worse moral standing happens due to a negative outcome.
- False Consensus: We believe more people agree with us than is actually the case.
- Curse of Knowledge: Once we know something, we assume everyone else knows it, too.
- Spotlight Effect: We overestimate how much people are paying attention to our behavior and appearance.
- Availability Heuristic: We rely on immediate examples that come to mind while making judgments.
- Defensive Attribution: As a witness who secretly fears being vulnerable to a serious mishap, we will blame the victim less if we relate to the victim.
- Just-World Hypothesis: We tend to believe the world is just; therefore, we assume acts of injustice are deserved.
- Naïve Realism: We believe that we observe objective reality and that other people are irrational, uninformed, or biased.
- Naïve Cynicism: We believe that we observe objective reality and that other people have a higher egocentric bias than they actually do in their intentions/actions.
- Forer Effect (aka Barnum Effect): We easily attribute our personalities to vague statements, even if they can apply to a wide range of people.
- Dunning-Kruger Effect: The less you know, the more confident you are. The more you know, the less confident you are.
- Anchoring: We rely heavily on the first piece of information introduced when making decisions.
- Automation Bias: We rely on automated systems, sometimes trusting too much in the automated correction of actually correct decisions.
- Google Effect (aka Digital Amnesia): We tend to forget information that’s easily looked up in search engines.
- Reactance: We do the opposite of what we’re told, especially when we perceive threats to personal freedoms.
- Confirmation Bias: We tend to find and remember information that confirms our perceptions.
- Backfire Effect: Disproving evidence sometimes has the unwarranted effect of confirming our beliefs.
- Third-Person Effect: We believe that others are more affected by mass media consumption than we ourselves are.
- Belief Bias: We judge an argument’s strength not by how strongly it supports the conclusion but how plausible the conclusion is in our own minds.
- Availability Cascade: Tied to our need for social acceptance, collective beliefs gain more plausibility through public repetition.
- Declinism: We tent to romanticize the past and view the future negatively, believing that societies/institutions are by and large in decline.
- Status Quo Bias: We tend to prefer things to stay the same; changes from the baseline are considered to be a loss.
- Sunk Cost Fallacy (aka Escalation of Commitment): We invest more in things that have cost us something rather than altering our investments, even if we face negative outcomes.
- Gambler’s Fallacy: We think future possibilities are affected by past events.
- Zero-Risk Bias: We prefer to reduce small risks to zero, even if we can reduce more risk overall with another option.
- Framing Effect: We often draw different conclusions from the same information depending on how it’s presented.
- Stereotyping: We adopt generalized beliefs that members of a group will have certain characteristics, despite not having information about the individual.
- Outgroup Homogeneity Bias: We perceive out-group members as homogeneous and our own in-groups as more diverse.
- Authority Bias: We trust and are more often influenced by the opinions of authority figures.
- Placebo Effect: If we believe a treatment will work, it often will have a small physiological effect.
- Survivorship Bias: We tend to focus on those things that survived a process and overlook ones that failed.
- Tachypsychia: Our perceptions of time shift depending on trauma, drug use, and physical exertion.
- Law of Triviality (aka “Bike-Shedding”): We give disproportionate weight to trivial issues, often while avoiding more complex issues.
- Zeigarnik Effect: We remember incomplete tasks more than completed ones.
- IKEA Effect: We place higher value on things we partially created ourselves.
- Ben Franklin Effect: We like doing favors; we are more likely to do another favor for someone if we’ve already done a favor for them than if we had received a favor from that person.
- Bystander Effect: The more other people are around, the less likely we are to help a victim.
- Suggestibility: We, especially children, sometimes mistake ideas suggested by a questioner for memories.
- False Memory: We mistake imagination for real memories.
- Cryptomnesia: We mistake real memories for imagination.
- Clustering Illusion: We find patterns and “clusters” in random data.
- Pessimism Bias: We sometimes overestimate the likelihood of bad outcomes.
- Optimism Bias: We sometimes are over-optimistic about good outcomes.
- Blind Spot Bias: We don’t think we have bias, and we see it others more than ourselves.
Use our cognitive bias infographic as inspiration for becoming better and knowing more! You can even print it out and use it as a cognitive bias poster to encourage others to do the same.