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Distortions of Memory

The Biology of Memory

Quick Review

Memories aren’t exact records of events. Instead, memories are reconstructed in many different ways after events happen, which means they can be distorted by several factors. These factors include schemas, source amnesia, the misinformation effect, the hindsight bias, the overconfidence effect, and confabulation.


A schema is a mental model of an object or event that includes knowledge as well as beliefs and expectations. Schemas can distort memory.

Example: Suppose a high school junior visits her sister’s college dorm room for the first time. She’s never been to a dorm before, but she’s seen dorms in movies, read about them, and heard her friends talking about them. When she describes the room to another friend after the visit, she comments on how many clothes her sister had and how many huge books were on her sister’s desk. In reality, the books were hidden under the bed, not out in the open. The clothes were something she actually saw, while the books were part of her dorm-room schema.

Source Amnesia

Another reason for distorted memories is that people often don’t accurately remember the origin of information.

Example: After witnessing a car crash on the freeway, Sam later tells friends many details about what he saw. It turns out, however, that there is no way he could have actually seen some of the details he described and that he is, in fact, just reporting details he heard on TV about the accident. He isn’t deliberately lying. He just may not be able to remember where all the different pieces of information came from.

This inaccurate recall of the origin of information is called source amnesia, source misattribution, or source monitoring error.

The Misinformation Effect

The misinformation effect occurs when people’s recollections of events are distorted by information given to them after the event occurred. The psychologist Elizabeth Loftus did influential research on the misinformation effect that showed that memory reconstructions can affect eyewitness testimony.

Example: A bank robber enters a crowded bank in the middle of the day, brandishing a gun. He shoots out the security cameras and terrifies everyone. He is taking money from a teller when one of two security guards approaches the robber, draws his own weapon, and shoots. Suddenly, another shot is fired from a different direction and the security guard falls to the ground, shot. Some of the customers see that the other security guard, who was approaching the robber from the other side, mistakenly shot his partner. Later, police ask the witnesses when the robber shot the guard, and they report that he shot after the guard fired on him. Even though they saw one guard shoot the other, they are swayed by the misinformation given by the police.

The Hindsight Bias

The hindsight bias is the tendency to interpret the past in a way that fits the present. For example, if Laura’s boyfriend cheats on her, she may recall the boyfriend as always having seemed promiscuous, even if this is not true.

The Overconfidence Effect

The overconfidence effect is the tendency people have to overestimate their ability to recall events correctly.

Example: Tina asks her father to tell her all about the day she was born: when her mother first went into labor, how long it took to get to the hospital, what time of day or night it was. Tina’s father tells her a wonderful story about how he and her mother made a late night rush to the hospital the night of Thursday, the twelfth, and how Tracy’s mother barely made it into the delivery room before Tracy emerged, and how the doctor kindly put 11:59 p.m. as the time of birth to avoid a Friday the thirteenth birthday. Years later, when glancing at an old calendar, Tracy discovers she was actually born on a Tuesday, not a Thursday.


Sometimes people claim to remember something that didn’t happen or think that something happened to them when it actually happened to someone else. This phenomenon is confabulation.

Example: Steve is in his early twenties, and he and a roommate have just moved to New York City. Steve has all sorts of interesting experiences. One night, he goes out to a local pub and meets Robert De Niro, who is just sitting there eating a hamburger. The two of them chat about baseball for a while and even shoot a game of pool. Later, Steve tells his roommate about the evening. Many years later, Steve and his old roommate get together to talk about old times, and the roommate relates the “De Niro story” as if it happened to him.

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