Common Biases
•This bias is the tendency to search for or interpret information in a way that confirms one’s preconceptions
•A person who believes left-handed people are more creative only notices examples of creative left-handed people while ignoring equally creative right-handed people.
Confirmation Bias
•The tendency to rely too heavily, or “anchor” on a past reference or on one trait or piece of information when making decisions.
•When buying a used car, the seller starts with a very high price; even if the buyer negotiates down, their final offer is still biased by the initial “anchor.”
Anchoring Effect
•The tendency to overestimate the probability of good things happening.
•Someone starting a new business assumes it’s very unlikely they’ll fail, even though most startups close within five years.
Positive Outcome Bias or Optimism Bias
•The tendency for people to like things to stay the same. The tendency to defend and bolster the status quo. Existing social, economic, and political arrangements tend to be preferred, and alternatives disparaged sometimes even at the expense of individual and collective self-interest. Ex. Staying in a bad relationship, not taking a chance on a better job, remaining in the same place at the expense of a better choice because “things are fine” the way they are.
•An employee sticks with outdated software because “we’ve always used it,” even though newer tools would be faster.
Status Quo Bias
•The tendency to concentrate on the people or things that “survived” some process and ignoring those that didn’t, or arguing that a strategy is effective given the winners, while ignoring the large amount of losers.
•Looking at successful entrepreneurs like Steve Jobs or Elon Musk and assuming anyone can succeed by “working hard,” while ignoring the vast number of failed startups.
Survivorship Bias
•The tendency to think that future probabilities are altered by past events, when in reality they are unchanged. For example, “I’ve flipped heads with this coin five times consecutively, so the chance of tails coming out on the sixth flip is much greater than heads.”
•After losing five coin tosses in a row, someone believes the next flip is “due” to be a win.
Gambler's Fallacy
•The tendency to remember one’s choices as better than they actually were.
•After buying an expensive phone, the buyer downplays its flaws and overstates its benefits to feel better about their choice.
Choice Supportive Bias
•The tendency to overestimate one’s ability to show restraint in the face of temptation.
•A dieter buys junk food, convinced they’ll resist eating it later, but then ends up snacking.
Restraint Bias
•A form of misattribution where ideas suggested by a questioner are mistaken for memory.
•A witness remembers seeing a blue car at a crime scene because the police asked, “Was the blue car speeding?”
Suggestibility
•The tendency to judge a decision by its eventual outcome instead of based on the quality of the decision at the time it was made.
•A company praises a risky business decision because it worked out, even though it was based on poor reasoning.
Outcome Bias
•The tendency for human beings to believe they can control or at least influence outcomes that they clearly cannot.
•Blowing on dice before rolling, believing it increases the chance of rolling a six.
Illusion of Control
•Incorrectly remembering one’s past attitudes and behavior as resembling present attitudes and behavior.
•A person who now supports climate action insists they always cared deeply about the environment, even if their past actions show otherwise.
Consistency Bias
•The urge to do the opposite of what someone wants you to do out of a need to resist a perceived attempt to constrain your freedom of choice.
•A teenager is told not to dye their hair and immediately feels an urge to do it.
Reactance
•Perceiving oneself responsible for desirable outcomes but not responsible for undesirable ones.
•A student attributes their good grade to hard work, but a poor grade to unfair test questions.
Self Serving Bias
•Phenomenon in which humans pay more attention to and give more weight to negative than positive experiences or other kinds of information.
•After receiving ten compliments and one criticism, someone dwells only on the criticism.
Negativity Bias
•The fallacy of selecting or adjusting a hypothesis after the data is collected, making it impossible to test the hypothesis fairly. Refers to the concept of firing shots at a barn door, drawing a circle around the best group, and declaring that to be the target.
•A company highlights one region where their product sold well while ignoring many regions where it failed.
Texas Sharpshooter fallacy
•Filtering memory of past events through present knowledge, so that those events look more predictable than they actually were; also known as the “I knew it all along” effect.
•After a sports team wins, fans insist they “knew it all along” despite having doubts before the game.
Hindsight Bias
•Excessive confidence in one’s own answers to questions. For example, for certain types of questions, answers that people rate as 99% certain turn out to be wrong 40% of the time.
•A driver believes they’re “much safer than average,” even though statistically most people can’t be above average.
Overconfidence Effect
•A vague or random stimulus (often an image or sound) is perceived as significant. Ex. seeing images of animals or faces in the clouds, the man in the moon, or hearing hidden messages in reverse.
•Seeing the face of Jesus in a piece of toast.
Pareidolia
•Using an approach or description of the situation or issue that is too narrow. Basing a conclusion on how the data is presented (framed).
•A surgery is described as having a “90% survival rate” vs. “10% mortality rate” — people react more positively to the first framing.
Framing
•Expecting a member of a group to have certain characteristics without having actual information about that person.
•Assuming that women are worse drivers than men without evidence.
Stereotyping
•The tendency for people to over-emphasize personality-based explanations for behaviors observed in others while under-emphasizing the role and power of situational influences on the same behavior.
•Example; the other team lost the game because they are poor players, while our team lost because it was raining that day. (Even though it was also raining when the other team played.)
Fundamental Attribution Error or Actor-Observer Bias
•Ignoring an obvious (negative) situation. AKA “Burying your head in the sand.”
•Avoiding checking a bank account after a weekend of heavy spending.
Ostrich Effect
•The tendency to see patterns where in fact none exist.
•Believing a basketball player is on a “hot streak” because they made three shots in a row, even though each shot is independent.
Clustering Illusion
•Estimating what is more likely by what is more available in memory, which is biased toward vivid, unusual or emotionally charged examples.
•After seeing news reports of airplane crashes, someone fears flying more than driving, even though driving is riskier.
Availability Heuristic