Thinking Flaws

A collection of all thinking flaws - cognitive biases, fallacies, psychological weirdities and more.

Every cognitive bias is there for a reason - primarily to save our brains time or energy. If you look at them by the problem they're trying to solve, it becomes a lot easier to understand why they exist, how they're useful, and the trade-offs(resulting mental errors) that they introduce.

Cognitive Biases addresses these issues...

1. Information overload

Our brain filters out information that it thinks is not important. There is too much information available - its not practical to process all of it.

Notice only that are primed or repeated

  • Hot-Cold Empathy Gap

    There is a significant difference in how we act in an emotionally charged state(hot state) when compared to your normal state(cold).

  • Context effect

    We might not be able to recall information without memory aids/cues that we used at study.

  • Mere-Exposure Effect

    Psychological phenomenon by which people tend to develop a preference for things merely because they are familiar with them.

  • Attentional bias

    What we believe/want influences what we focus on/notice.

  • Frequency illusion

    Once you learn a new word/concept, you see it everywhere.

  • Illusory truth effect

    We believe incorrect information to be correct after repeated exposure.

  • Recency bias

    More significance is given to a recent event/data/evidence when compared to past events/data/evidence.

  • Availability Heuristic

    You overestimate the probability of something that you hear more often/remember easily.

Bizarre/funny/visually-striking/anthropomorphic are more Noticeable

We generally skip information that's ordinary or expected.

Change is Noticed Prominantly

  • Framing effect

    People's choices can change based on how the question is framed or worded.

  • Distinction bias

    When evaluating between two options, we view them as very different - as compared to evaluating them separately(we would have evaluated them very close to each other).

  • Anchoring Effect

    Choices are affected by an anchor.

  • Weber–Fechner law

    Perceived difference is not the same as actual difference.

Drawn to details that confirms existing beliefs

And ignore/miss details that contridicts our beliefs

We notice flaws in others easier than in ourselves.

  • Bias blind spot

    It's more difficult to notice biases in ourselves.

  • Naive realism

    Belief that our view of the world is objective, and people who disagree are irrational/biased/misinformed.

  • Naive Cynicism

    Expecting others to be biased all the time.

2. Not enough meaning

The world is too complex to understand fully. So we compensate by filling in the gaps of our understanding to make better sense of it - or at least have a belief that we have an understanding of the world. We assign meaning to the world - we do our own sensemaking.

We find patterns and meaning even with little data

Our brain needs to feel that it has a coherent model/story about the situation - even if we have too little information about it.

  • Clustering illusion

    Belief that streaks or clusters in parts of random data are non-random.

  • Anecdotal fallacy

    We believe that personal experience/anecdotal examples trumps data or logical argument.

  • Neglect of probability

    Tendency to ignore probability when making decisions in uncertain conditions.

  • Gambler's fallacy

    If an unlikely event(that's statistically independent) occurred multiple times, it's less likely to occur in the future.

  • Anthropomorphism

    Assigning human traits, attributes, emotions or agency to non-human things.

  • Confabulation

    Memory error - people sometimes have wrong/distorted memories that they are confident about.

  • Hot-hand fallacy

    Belief that someone who has been successful will be more likely to be successful in future attempts.

  • Insensitivity to sample size

    People tend to ignore sample size of data. They forget that variation is more likely in smaller sample sizes.

  • Illusory correlation

    Perceiving a relation between things(people, behaviours, events, etc) when no such relation exists.

  • Illusion of validity

    Overestimation of ability to interpret and predict outcome when analysing data that shows a consistent pattern.

  • Pareidolia

    Seeing a pattern/meaning where there is none.

We jump to conclusions using stereotypes, generalities, past occurrences.

When we have only limited information/gap in knowledge we tend to fill in the gaps using best guesses from stereotypes and generalities. Once its done, we can't easily determine which part is real and which part is filled up.

  • Placebo effect

    An inert pill can cure health issues if the patient believes that it will.

  • Automation bias

    Tendency to believe decisions from an automated decision making system have more accuracy. And even ignore contradictory information made without automation.

  • Bandwagon effect

    Tendency to follow the crowd. Adopting behaviours, practices, attitudes, beliefs only because others are doing it.

  • Authority bias

    We believe that the views of an authority figure(Eg. God, Govt., Parent) is more accurate - and let it influence our options.

  • Argument from fallacy

    The idea that since an argument had a logical fallacy in it, it must be false.

  • Functional fixedness

    Cognitive bias that limits your imagination of how an object can be used to only its traditional use.

  • Essentialism

    Philosophical view that all things have a set of properties that are necessary to their identity.

  • Group attribution error

    Belief that the characteristics of one person in a group must be there in all.

  • Just-world hypothesis

    Belief that people will get what they deserve. Or Everything happens for a reason.

  • Moral credential effect

    A previous 'good' behaviour will make it easier to do 'bad' behaviour.

  • Stereotyping

    General belief about a group of people - and expects that belief to be true of all individuals in the group.

  • Ultimate attribution error

    Explains the negative behaviours of out-group(others) to personality defects and negative behaviours of the in-group(us) to external circumstances or chance.

Belief that liked or known things are better

Belief that people/things we like or familiar with are better than that we don't like/are familiar with.

Simplification of Probability and Numbers

Subconscious mind is bad at maths - and uses simplification to optimize decision making. This can get wrong results.

  • Denomination effect

    Less likely to spend a large denomination currency than the equal value in smaller notes.

  • Subadditivity effect

    Belief that probability of the whole is lesser than the sum of probabilities of the parts.

  • Mental accounting

    People tend to assign subjective value to money - this is susceptible to biases, thinking flaws.

  • Appeal to probability fallacy

    Belief that if it's possible, then it's probable.

  • Base rate fallacy

    We tend to overvalue the specific information - rather than integrating it with general information like the base rate.

  • Conservatism

    People don't easily change existing belief even when presented with new evidence.

  • Hofstadter's law

    It describes the widely experienced difficulty of accurately estimating the time it will take to complete tasks of substantial complexity.

  • Money illusion

    People mistake the face value of money(the amount of money) with the real value(what it can buy).

  • Magic number 7+-2

    Number of items that can be held in short term memory: 7 +/- 2

  • Normalcy bias

    The brain sometimes ignores multiple warnings signals.

  • Survivorship bias

    Concentrating on the people/things that got past a selection point.

  • Swimmer's body illusion

    People confuse selection factors with results.

  • Time-saving bias

    We underestimate time saved when moving from a relatively smaller speed to higher speed. Also, we overestimate time saved when moving from a relatively faster speed to even faster speed.

  • Zero sum bias

    Belief that your situation is a zero sum situation and competing - even when there are unlimited resources.

We think we know what others think

We model the thinking of other people based on our own mind or a much simpler mind than ours.

  • Bystander effect

    Individuals are less likely to offer help to a victim when there are other people present.

  • Curse of knowledge

    When communicating with others, we assume that they have all the background information about the topic that we have already.

  • Extrinsic incentive error

    We think other people are driven more by extrinsic motivators(like monetary reward) and we are driven more by intrinsic motivators(learning a new skill).

  • Illusion of transparency

    We think other people can understand our mental state fairly accurately.

  • Illusion of external agency

    A belief that good/bad things happen to us because of external influences rather than personal actions.

  • Illusion of asymmetric insight

    Belief that we know other people better than the other person knows us.

  • Spotlight effect

    We think we are noticed/thought about by others way more than we actually are.

Current mind state is projected to past and future

  • Pessimism bias

    We exaggerate the probability of bad things happening to us.

  • Pro-innovation bias

    If we see an innovation at work, we tend to believe that it can be applied everywhere without need of alterations.

  • Projection bias

    We forecast our current preference on to a future event.

  • Hindsight Bias

    People tend to think that events could have been easily predictable AFTER the outcome is clear.

  • Impact bias

    We overestimate duration and intensity of future emotional states.

  • Declinism

    Belief that a society or institution is becoming worse over time.

  • Moral luck

    Assigning praise or blame of an action based on outcome even if its not fully in their control.

  • Outcome bias

    Evaluating the quality of a decision after the outcome is known.

  • Planning fallacy

    We underestimate time required to finish a task.

  • Rosy retrospection

    We judge past events more positively than we do the present.

  • Restraint bias

    We overestimate our ability to control impulsive behaviour.

  • Self-consistency bias

    We believe that we are consistent in our beliefs, behaviours, options, attitudes, etc.

  • Telescoping effect

    Events in the past or future seems more distant(backward telescoping/time expansion) or nearer(forward telescoping) than they actually are.

3. We have to act fast

We evolved with the need to make quick decisions when faced with limited time and information. This programming continues in the present time in form of these thinking flaws.

To act, we should feel important and impactful

  • Egocentric Bias

    We overestimate our own perspective.

  • Third-person effect

    We think that mass media affects other people more than it affects us.

  • Illusion of control

    We overestimate how much control we have over situations.

  • Defensive attribution hypothesis

    We tend to believe theories about the cause of a mishap in a way that minimizes our own blame or threat in that mishap.

  • Fundamental Attribution Error

    We attribute the reason of our own(or of our friends) failures to the environment, but the failures of others(or our enemies) to their character.

  • Optimism Bias

    We exaggerate the probability of good things happening to us.

  • Hard Easy Effect

    Hard tasks makes you overconfident - and predict higher success probability while easier tasks makes you under confident - and predict lower success.

  • Effort justification

    If we put in a lot of effort into something, its value will go up in our mind.

  • Illusory superiority

    We overestimate our own qualities and abilities when compared to other people.

  • Dunning-Kruger Effect

    Dunning–Kruger effect is a cognitive bias in which people with low ability at a task overestimate their ability.

  • Barnum effect

    We think that vague and generic personality descriptions that can apply to a lot of people are very accurate and made specifically for them.

  • False consensus effect

    We think our beliefs, behaviours, personal qualities are the norm.

  • Overconfidence effect

    We overestimate our performance, think our performance is better than that of others, and think we have more accurate beliefs.

  • Risk compensation

    We adjust behaviour according to perceived risk - we are more risk taking when we feel protected, and more careful when we sense greater risk.

  • Self serving bias

    Our thinking and perception is distorted in ways to enhance our self esteem.

  • Trait ascription bias

    We think that our traits, attitudes, behaviours, moods are relatively variable(it can change as needed) - but other peoples traits are more predictable and static.

  • Social-desirability Bias

    Survey respondents will give answers that be viewed favourably by others.

Favor immediate, known things over distant ones

We favor present over future. Stories about specific individuals over anonymous person.

  • Hyperbolic discounting

    We discount the value of a reward given later by a factor of the delay in getting the reward.

  • Appeal to novelty

    We believe that things are better just because they are new.

  • Identifiable victim effect

    We are more willing to help a specific, identifiable person over a large but vaguely defined group with the same issue.

We want to finish things we have invested in

Helps us to finish things, even with difficult. Actions have inertia - once started its easier to continue.

  • Endowment effect

    We want to keep a thing we own more than we want to get the same thing when we don't own it.

  • IKEA effect

    We value things much higher if we created them(even partially).

  • Zero risk bias

    We prefer to eliminate risks completely in a smaller part rather than reduce overall risk even if the second option reduces risk to a greater extend.

  • Backfire effect

    When we are presented with evidence against a pre-existing belief that we had, we sometimes reject the evidence and hold the belief even more strongly.

  • Generation effect

    We remember things better if our own mind makes it up rather than when we just read it.

  • Pseudocertainty effect

    We think of an outcome as certain - but in reality if we zoom out, it would be part of a multi-step process - which in entirety is not certain.

  • Sunk Cost Fallacy

    People generally put in more investment into a failing thing to win back the investment that has already gone in.

  • Unit bias

    We want to finish a unit of anything we are consuming - we don't want to stop in the middle.

  • Disposition effect

    When doing stock investing, we tend to sell off stocks that do well/increase in price - and keep the stock that is performing poorly.

  • Irrational escalation

    When we get negative feedback for an outcome we are invested in, we increase effort towards it instead of altering course.

  • Loss aversion

    We prefer to avoid making a loss over making a profit of the same value.

We want to have autonomy and status. Also, we want to avoid irreversable decisions

  • Status quo bias

    We prefer the current situation. We tend to think it is better than other alternatives.

  • Reverse psychology

    Reverse psychology is a manipulation technique that asks someone to do something opposite to the action that is actually required.

  • Hippo Effect

    Hippo - or Highest Paid Person's Opinion. In meetings, there might be a person who has the most experience or authority(usually the boss). Decisions they make might go unchallenged.

  • Abilene paradox

    It is possible for a group to decide on something that is against most or all of the group members' preference.

  • Chesterton's fence

    Ideally, we should not change something until we understand the purpose behind it.

  • Decoy effect

    When deciding between two options, an unattractive third option can change the perceived preference between the other two.

  • Law of the instrument

    We tend to over-rely on a familiar tool.

  • Reactance

    Reactance is the resistance we feel when there is a threat to our behavioural freedom.

  • Social comparison bias

    We have a feeling of dislike and competitiveness towards people who we think are better than us.

  • System justification

    We tend to defend the system we are in because it provides for many of our underlying needs.

We prefer simple or complete options over complex, ambiguous options

  • Information bias

    We want to search for information even when it does not affect the decision.

  • Ambiguity effect

    We prefer options with known probability over options with unknown probability even if the payout is smaller in the known option.

  • Belief bias

    We judge arguments based on the probability of the conclusion rather than how strongly the argument supports the conclusion.

  • Bike shed effect

    We tend to spend more time on figuring out trivial things rather than spending time on the important things.

  • Conjunction fallacy

    We think that specific conditions are more probable than a single general condition.

  • Occam's razor

    The simplest explanation is often the best one.

  • Linguistic relativity

    The languages you know influence your cognition and world view.

  • Less-is-better effect

    lesser option is preferred when evaluated separately.

  • Rhyme as reason effect

    We believe that proverbs, sayings etc. are more accurate if it rhymes.

  • Delmore effect

    We tend to have more defined and articulated goals about parts of our lives which has lower priority.

4. What to remember

We have to prioritize what to remember and what to discard. We have a set of filters that will help us do this - but it can cause issues too.

We edit memories after the event

  • Cryptomnesia

    We some times remember something that was forgotten - but we think that is an original thought that we made.

  • Misattribution of memory

    We tend to wrongly identify the source of a memory at point of recall.

  • Suggestibility

    Suggestibility is tendency to accept or act on the suggestion of others.

  • Broaden-and-build Theory

    Negative emotions have immediate survival benefits. Positive emotions have long term benefits.

  • False memory

    Memory error that can create slightly wrong or wildly inaccurate recollection that the person is very confident about.

  • Spacing effect

    Recollection of memory is better if we try to remember that information at specific intervals.

  • Social identity theory

    Social identity is the part of a person's self-concept that is made from their membership in a social group.

We discard specifics to create generalizations

  • Fading affect bias

    Memories associated with negative emotions are forgotten more quickly than memories associated with positive emotions.

  • Implicit stereotype

    We assign certain qualities to a member of an out group.

  • Prejudice

    Prejudice is a preconceived(usually unfavourable) assignment of qualities to members of an out group.

We reduce events and lists to its key elements

We chose a few items to represent the whole.

  • Serial recall

    We are able to recollect items or events in the order they are given.

  • Misinformation effect

    Our memory can change and become less accurate based on information we get after the event.

  • Modality effect

    Our memory of things we study is based on the presentations of the material.

  • Peak End Rule

    We judge an experience based on what happens at either the peak(most intense part of the experience) or at the end of the event rather that the entire event.

  • Serial-position effect

    We tend to recall the first(Primacy effect) and last items(Recency effect) in a series.

  • Suffix Effect

    The Serial-position effect ie. strong recall of last item of the list, will be impaired if there is an irrelevant item(that need not be remembered) at the end of the list.

  • Duration neglect

    Our judgment of how unpleasant an experience is does not depend on the duration of the event - but on the peak(most intense part) and how quickly the pain reduces.

  • Memory inhibition

    Memory inhibition is the ability NOT to remember irrelevant information.

  • Levelling and sharpening

    There are automatic functions of memory. Sharpening is when we remember small details in retelling of a memory. Levelling is when we leave out parts of the memory.

We store memory differently based on how the experience was

Our brain will save things that it thinks is important. Importantce is judged based on the situation - not just the value of the information. Eg. Traumatic memories can be very strong.


I've stood on the shoulders of gaints to create this site. Most of the heavy lifting was done by brilliant people before me...

  • Many Psycologists over the last few decades who did the original research.
  • All the wikipeda contributers for biases I have listed. Most of the source in the bias leads you to a wikipeda page.
  • Buster Benson for categorization and clustering.