Memory Errors, Memory Gaps Reasons why we remember so much and so little at the same time

Memory Errors, Memory Gaps

Reasons why we remember so much and so little at the same time...

Memory and its failures

Why do memory errors happen?- Semantic activation - Inferences- Schemas- Update of memory

Memory errors & everyday life- In the court- In therapy- In important events of your life

Semantic Activation

• Example:– You will hear a list of words, once the list ends, recall as many words

as possible

– Bed, Rest, Awake, Snooze, Tired, Dream, Blanket, Doze, Slumber, Snore, Nap, Yawn, Drowsy

– Missing word: ‘sleep’

•

Inference in Recognition Memory

• John was trying to fix the bird house. He was pounding the nail when his father came out to watch him and to help him do the work.

Recognition test: “John was using the hammer to fix the bird house when his father came out to watch him and to help him do the work.”

• John was trying to fix the bird house. He was looking for the nail when his father came out to watch him and to help him do the work.

with the hammer

with the hammer

Schema (script): A high-level representation of knowledge about familiar situations.

Schemata help us to deal with the world efficiently by representing those aspects of our experience that are usually the same from one time to another…

Event Schema (script): Going to a restaurant• Enter

– Walk into restaurant

– Look for table

– Decide where to sit

– Go to table

– Sit down

• Order– Get menu

– Choose food

– Waiter arrives

– Give orders to waiter

– Wait, talk

– Cook prepares food

• Eat– Cook gives food to waiter

– Waiter delivers food

– Eat

– Talk

• Leave– Waiter delivers bill

– Examine bill

– Calculate tip

– Leave tip

– Get belongings

– Pay bill

– Leave restaurant

Memory Update: Misinformation Effect• See event: film of two-car accident

• Receive misinformation

– When the cars smashed each other,

– When the cars hit each other,

• Memory test: the speed was … – a) “smashed” (41 mph)

– b) “hit” (34 mph)

Is this a ‘memory’ distortion, or a report bias?

A week later: Did you see broken glass? (correct answer: no) a) “smashed”: 32% yes

b) ‘hit’: 14% yes

(Elizabeth Loftus)

(Loftus & Palmer, 1974)

Relevance to Criminal Justice System

• most obvious case

– crime --> study

– picture of suspect --> misinformation

– Lineup --> test• Eyewitness may recognize suspect from police display, not from crime

scene.

• Conclusions:– Do not let potential witnesses see suspects.– Interrogate without asking leading questions (Capturing the Freedmans)

• Further sources of error:– newspaper stories, etc.

Memory Contamination & Psychotherapy

•Therapist repeatedly asks child about abuse at day care center. Eventually, child “remembers” abuse.

•Therapist repeatedly asks woman about childhood abuse. Eventually, woman “recovers repressed memory” of abuse.

Are these repressed memories or false memories?

Big debate! (Loftus vs. Freyd)

Autobiographical flashbulb memory

• A type of episodic memory• Memory for personal experiences• Components

• Imagery (e.g., visual imagery)• Lots of detail (flashbulb memory: where were you on 9/11?)

• High confidence in its accuracy (even if it is wrong!)

• Emotion

• It has a narrative (it tells a story), thus

• It is constructive– is biased by goals at the time of retrieval

MemoryMemory• memory illusion - a false but convincing memory (false

memory task, 1st day of class)

• Memory is reconstructive - we extract the gist to make things easier to remember (but this may contribute to memory errors)

Copyright © Allyn & Bacon 2009

Suggestibility and Suggestibility and Child TestimonyChild Testimony

• Young children are especially vulnerable to suggestions to recall events that did not occur– May cling to false memory, even when assured

it did not occur– Repeated questioning may elicit

misinformation– Especially affected by schemas


False MemoriesFalse Memories• Flashbulb memories - very vivid, able to be

recalled in detail– But subject to change over time, just like other memories

• Study of Challenger explosion

• Source monitoring - ability to identify the origins of a memory–


Implanting False Implanting False Memories in the LabMemories in the Lab

• Implanted memories– Lost in the mall study

– Easier to implant memory for • Plausible events

• Events in the distant past

– Existence proofs for implanted memories• Hot air balloon ride

• Bugs Bunny at Disneyland

– Demand characteristics? Not likely, many subjects continue to insist on the validity of false memories even when told they are implanted


Eyewitness TestimonyEyewitness Testimony• Weak correlation between witness confidence

in their testimony and its accuracy – Less accurate when

• Observing others of different race• Witness has talked to other witnesses• The observed situation is stressful (e.g., threatening,

weapon involved)

– Improved accuracy with sequential (vs. simultaneous) lineup


Schacter’s Seven Sins of MemorySchacter’s Seven Sins of Memory

1. Suggestibility

2. Misattribution

3. Bias

4. Transience

5. Persistence

6. Blocking

7. Absentmindedness

Documents

Memory Errors, Memory Gaps Reasons why we remember so much and so little at the same time