[2020] Ultimate List of Cognitive Biases with examples (Part 4 of 4)

Section One

Section Two

Section Three

Section Four

Section Four

Not enough memory

There’s too much information in the universe. We can only afford to keep around the bits that are most likely to prove useful in the future. We need to make constant bets and trade-offs around what we try to remember and what we forget. For example, we prefer generalizations over specifics because they take up less space. When there are lots of irreducible details, we pick out a few standout items to save and discard the rest. What we save here is what is most likely to inform our filters related to problem 1’s information overload, as well as inform what comes to mind during the processes mentioned in problem 2 around filling in incomplete information. It’s all self-reinforcing.

Chapter Seventeen

We edit and reinforce some memories after the fact

During that process, memories can become stronger, however various details can also get accidentally swapped. We sometimes accidentally inject a detail into the memory that wasn’t there before.

Misattribution of memory

Misattribution is divided into three components: cryptomnesia, false memories, and source confusion.

Example – Attribute the memory to the wrong source. Thinking you invented the idea. Or just a false memory.

Source confusion 

Confusing episodic memories with other information, creating distorted memories.

Example – Source confusion is an attribute seen in different people’s accounts of the same event after hearing people speak about the situation. An example of this would be, a witness who heard a police officer say he had a gun and then that witness later says they saw the gun.


A form of misattribution where a memory is mistaken for imagination, because there is no subjective experience of it being a memory.

Example – A person may falsely recall creating an idea, thought, or joke, not intentionally engaging in plagiarism, but nevertheless believing to be the original source of memory.

False memory

A form of misattribution where imagination is mistaken for a memory.

Example – False memories are often the result of leading questions in a therapeutic practice termed Recovered Memory Therapy.

Satanic panic and day-care sex-abuse hysteria were moral panics in the 80’s and early 90’s all over the world. The most expensive criminal case in US history, McMartin preschool trial, is such an example where a social worker implanted memories into 360 children because a schizophrenic mother told tales of flying people and child abuse. Some of children stories involved flying witches, secret tunnels, flight in hot-air balloons, children getting flushed though toilets into secret abuse rooms.


A form of misattribution where ideas suggested by a questioner are mistaken for memory.

Example – Children are told by their parents they’re good singers, so from then on they believe they are talented while their parents were in fact being falsely encouraging.

Spacing effect

That information is better recalled if exposure to it is repeated over a long span of time rather than a short one.

Example – The spacing effect and its underlying mechanisms have important applications to the world of advertising. For instance, the spacing effect dictates that it is not an effective advertising strategy to present the some commercial back-to-back (massed repetition). Spaced ads were remembered better than ads that had been repeated back to back.

Reminiscence bump

The recalling of more personal events from adolescence and early adulthood than personal events from other lifetime periods.

Example – People from totalitarian states who have moved to a democratic state may still remember their young days fondly partly because they were more sexually attractive and had more energy.

Chapter Eighteen

We discard specifics to form generalities

We do this out of necessity, but the impact of implicit associations, stereotypes, and prejudice results in some of the most glaringly bad consequences from our full set of cognitive biases.

Implicit association 

The speed with which people can match words depends on how closely they are associated.

Example – Used to test implicit stereotype bias too. The Harvard Implicit Association Test features in most psychology textbooks, but is an example of great bias as it has not been possible to find any clear factor it is testing and it’s unrelated to racism overall.

Implicit stereotypes

An implicit bias, or implicit stereotype, is the unconscious attribution of particular qualities to a member of a certain social group.

Example – A psychology hypothesis. The correlation between implicit bias and discriminatory behavior appears weaker than previously thought. There is little evidence that changes in implicit bias correlate with changes in a person’s behavior.

Stereotypical bias

Memory distorted towards stereotypes (e.g., racial or gender).

Example – Jews were stereotyped as being evil and yearning for world domination. So antisemites may have memories about Jews that are extra negative.


Prejudice is an affective feeling towards a person based on that person’s perceived group membership.

Example – For example, Classism: “a biased or discriminatory attitude on distinctions made between social or economic classes.”

Negativity bias

The notion that, even when of equal intensity, things of a more negative nature have a greater effect on one’s psychological state and processes than neutral or positive things.

Example – When people are presented with a range of trait information about a target individual, the traits are neither “averaged” nor “summed” to reach a final impression. When these traits differ in terms of their positivity and negativity, negative traits disproportionately impact the final impression.

Fading affect bias

A bias in which the emotion associated with unpleasant memories fades more quickly than the emotion associated with positive events.

Example – Individuals were asked to keep dream journals in which they rated their feelings about their dreams when they happened and were later asked to recall how they felt about those same dreams. In line with previous findings about the nature of autobiographical memory, positive affect at time of occurrence and at time of recall decreased slower than that of negative affect.

Women are wonderful effect

A tendency to associate more positive attributes with women than with men.

Example – A study found that women’s in-group biases were 4.5 times stronger than those of men. And only women (not men) showed cognitive balance among in-group bias, identity, and self-esteem, revealing that men lack a mechanism that bolsters automatic preference for their own gender.

Chapter Nineteen

We reduce events and lists to their key elements

It’s difficult to reduce events and lists to generalities, so instead we pick out a few items to represent the whole.

Peak-end rule

That people seem to perceive not the sum of an experience but the average of how it was at its peak (e.g., pleasant or unpleasant) and how it ended.

For a more in-depth understanding of the peak-end rule check out this article by kent hendricks.

Example – Since most consumer interactions have set beginnings and ends, they fit the peak-end model. As a consequence, negative occurrences in any consumer interaction can be counteracted by establishing a firmly positive peak and end. This can be accomplished through playing music customers enjoy, giving out free samples, or paying a clerk to hold the door for patrons as they leave.

This amazing illustration of the conjunction fallacy was made by @cartoonbias. Do check out their work on Instagram.

Leveling and sharpening

Memory distortions introduced by the loss of details in a recollection over time, often concurrent with sharpening or selective recollection of certain details that take on exaggerated significance in relation to the details or aspects of the experience lost through leveling. Both biases may be reinforced over time, and by repeated recollection or re-telling of a memory.

Example – In storytelling one may add details to some parts to make the story vivid and realistic while keeping other parts hazy to make the reader fill out the details by engaging with the story.

Misinformation effect

Memory becoming less accurate because of interference from post-event information.

Example – Examples of such memories include fabricated stories about participants getting lost in the supermarket or shopping mall as children. Researchers often rely on suggestive interviews and the power of suggestion from family members, known as familial informant false narrative procedure. Around 30% of subjects have gone on to produce either partial or complete false memories in these studies.

Serial recall effect

There are certain effects observed when people recall series.

Example – Short words and first words are remembered better.

List-length effect

Serial recall ability decreases as the length of the list or sequence increases.

Example – A smaller percentage of items are remembered in a longer list, but as the length of the list increases, the absolute number of items remembered increases as well. For example, consider a list of 30 items (“L30″) and a list of 100 items (1100”). An individual may remember 15 items from L30, or 50%, whereas the individual may remember 40 items from L100, or 40%. Although the percent of L30 items remembered (50%) is greater than the percent of L100 (40%), more L100 items (40) are remembered than L30 items (15).

Duration neglect

The neglect of the duration of an episode in determining its value.

Example – Daniel Kahneman and Barbara Fredrickson showed subjects pleasant or aversive film clips. When reviewing the clips mentally at a later time, subjects did not appear to take the length of the stimuli into account, instead judging them as if they were only a series of affective “snapshots”.

Modality effect

That memory recall is higher for the last items of a list when the list items were received via speech than when they were received through writing.

Example – In a study a visual list of English words was found to have an immediate recall of 4.82 words while an auditory representation of this same list led to a memory span of 5.36, a statistically significant variance.

Memory inhibition 

While some memories are retained for a lifetime, most memories are forgotten.

Example – According to evolutionary psychologists, forgetting is adaptive because it facilitates selectivity of rapid, efficient recollection. For example, a person trying to remember where they parked their car would not want to remember every place they have ever parked. In order to remember something, therefore, it is essential not only to activate the relevant information, but also to inhibit irrelevant information.

Primacy effect

That items near the end of a sequence are the easiest to recall, followed by the items at the beginning of a sequence; items in the middle are the least likely to be remembered.

Example – A subject who reads a sufficiently long list of words is more likely to remember words toward the beginning than words in the middle.

Recency effect

When asked to recall a list of items in any order (free recall), people tend to begin recall with the end of the list, recalling those items best.

Example – May be caused by the fact that recent memories are not yet fully sorted into the important vs. unimportant categories.

Part-set cueing effect

Providing a portion of to-be-remembered items as test cues often impairs retrieval of the remaining un-cued items compared with performance in a no-cue (free-recall) control condition.

Example – Similar to Suffix effect.

Serial-position effect

Serial-position effect is the tendency of a person to recall the first and last items in a series best, and the middle items worst.

Example – Longer presentation lists have been found to reduce the primacy effect.

This amazing illustration of the conjunction fallacy was made by @cartoonbias. Do check out their work on Instagram.

Suffix effect

Diminishment of the recency effect because a sound item is appended to the list that the subject is not required to recall.

Example – Similar to part-set cueing effect.

Verbatim effect

That the “gist” of what someone has said is better remembered than the verbatim wording. This is because memories are representations, not exact copies.

Example – This is just a basic memory premise. We save information in compact way like a zip file on a PC. We need to remember the gist of the situation and the emotional valence to make us act accordingly.

Chapter Twenty

We store memories differently based on how they were experienced

Our brains will only encode information that it deems important at the time, but this decision can be affected by other circumstances (what else is happening, how is the information presenting itself, can we easily find the information again if we need to, etc) that have little to do with the information’s value.

Levels-of-processing effect

That different methods of encoding information into memory have different levels of effectiveness.

Example – Participants were given a list of 60 words. They were given 3 category questions. How is it visually presented? What are the phonetic qualities? And lastly, can you relate the word to a context from real life? The result of this study showed that the words which contained deep processing (the latter) were remembered better.


Absent-mindedness is where a person shows inattentive or forgetful behavior.

Example –

It can have three different causes:

1. a low level of attention (“blanking” or “zoning out”) 2. intense attention to a single object of focus (hyperfocus) that makes a person oblivious to events around him or her; 3. unwarranted distraction of attention from the object of focus by irrelevant thoughts or environmental events.

Testing effect

The fact that you more easily remember information you have read by rewriting it instead of rereading it.

Example – First described in a study from 1909. Flashcards are tools to tap into this effect as it forces the reader to recall the memory before reading the answer.

This amazing illustration of the conjunction fallacy was made by @cartoonbias. Do check out their work on Instagram.

Next-in-line effect

When taking turns speaking in a group using a predetermined order (e.g. going clockwise around a room, taking numbers, etc.) people tend to have diminished recall for the words of the person who spoke immediately before them.

Example – In an experiment the participants were each in turn reading a word aloud from an index card, and after 25 words were asked to recall as many of all the read words as possible. The results of the experiment showed that words read aloud within approximately nine seconds before the subject’s own turn were recalled worse than other words.

Google effect

The tendency to forget information that can be found readily online by using Internet search engines.

Example – In a big replication study published in “Nature, 2018” the Google-Effect was one of the experiments which could not be replicated. One replication study showed that 50% of cognitive psychology studies could be replicated while only 25% of social psychology studies could be replicated

When an author of the original study redid his study it was bound to show a positive effect yet again. 91.7% successful replication rates in studies with author overlap compared to 64.6% success replication rates without author overlap.

This amazing illustration of the conjunction fallacy was made by @cartoonbias. Do check out their work on Instagram.

Tip of the tongue phenomenon 

When a subject is able to recall parts of an item, or related information, but is frustratingly unable to recall the whole item. This is thought to be an instance of “blocking” where multiple similar memories are being recalled and interfere with each other.

Example – The tip of the tongue phenomenon was first described as a psychological phenomenon in the text “The Principles of Psychology” by William James.

Have you read part 1 yet?

Ultimate List of Cognitive Biases with examples (Part 1 of 4) – Too much info