Memory Decay and Distortion 1 & 2 (wk 3) Flashcards
List three factors that can influence Memory between storage and retrieval
- Passage of time (forgetting)
- Intervening knowledge/experience (learning)
- Misinformation (Gaining incorrect information regarding an event
Eyewitness memory is …….
Reconstructive
Hermann Ebbinghaus
- Investigated memory scientifically and systematically exploring how info is stored in the brain and decays over time
- Studied this by presenting participants with nonsense syllables and then asked them to recall these after different time delays
- Results led to the formulation of the Ebbinghaus forgetting curve which suggests forgetting is a non-linear process
The Forgetting Function
Forgetting functions describe how accuracy or discriminability declines as the temporal distance from the event to be remembered increases.
This was one of Ebbinhaus’s findings in developing the forgetting curve
Describe how Memory becomes fragile in recall
Memory is formed through encoding and consolidation.
When we retrieve or recall information from our memory, it moves from a stable, consolidated format into a neurobiologically fragile state which is susceptible to change. As such, when memory is recalled and reconsolidated, the memory trace itself can change
What did Soren Kierkegaard say about Intervening Knowledge/Experience?
“Life is backwards, but must be lived forwards”
This stresses the idea that our memory guides our future actions, and that memory is continually being updated to integrate new and present knowledge
Snyder and Uranowitz 1978 Study on Intervening Knowledge/Experience and Memory
- Participants were presented with a case history about “Betty K”
- After one day or one week from reading the case history, participants were told that Betty was either straight or gay (or a control group was told nothing)
- Then participants’ memory for the case history was assessed
Findings showed the delay before intervening was unimportant but that participants made more label-consistent errors in recall than label-inconsistent errors.
Aka. Intervening knowledge (Betty’s sexuality) attributed for some error in the memory trace regarding the case history
Hindsight Bias
= When knowledge of current events, emotions, or outcomes, bias judgments, and the memory of processes leading up to those judgements.
(ie. I always knew he’d cheat on her)
- This is a product of intervening knowledge/experience infiltrating our memory trace
(eg. the more clues we get someone is a cheater, the more likely we are to think we always had doubts about them)
Hindsight bias can both influence our judgements and our memory for past events
Davis, Lopez, Koyama et al., 2005 study on Intervening Knowledge/Experience
Participants listened to an audio tape of a couple arguing
- Half the participants were told the couple subsequently broke up
- The other half were told the female was murdered, and her bf was a suspect in the murder
Participants were then tested on their memory for the audio tape
When told she was murdered, participants were more likely to accurately remember the threatening statements made by the male, however, were more likely to inaccurately recall aspects of the story (like he hit her and threatened her classmate etc)
(like being a liberal responder in a SDT with more hits and more false positives)
Misinformation and Memory
Misinformation is any information gained after a memory is laid down that was not part of the original event. (aka. Post event information)
Misinformation can reliably interfere with our memory trace
Elizabeth Loftus; Standard Misinformation Procedure
- Event (expose a participant to something)
- After some duration of time mislead the participant by planting inaccurate information
- After another duration of time interview the participant about the original event
eg. Watch red car in an accident –> ask “how fast was the blue car going” –> What colour was the car?
Misinformation Effect
Is a robust memory effect, in which misinformation becomes part of our memory trace
TWA 800 Flight as an example of memory inaccuracy
In the 1900’s TWA Flight 800 left New York and crashed shortly after near Long Island
There were no survivors in the crash but many eyewitnesses.
One eyewitness reported seeing something ‘hit’ the plane and media speculated it was a missile which caused the crash
Speculation in media and eyewitness reports were everywhere, until people were convinced they saw the missile hit the plane and believed when reports revealed the plane crashed due to a faulty fuel tank that the government were covering up a terrorist attack
What are three sources of misinformation in memory
- Media
- Other witnesses (co-witness discussions)
- Investigators (ie police)
Media as a source of misinformation ; Ei AI Crash, Amsterdam 1995
Shows how media can be both a good investigative tool but also a source of misinformation
- A plane crashed into an apartment at night and there was no video footage
- media speculated what could have happened
- in a survey 6 - 9 months after the crash 50% of people believed they had seen video footage of the crash
This shows how media reports are impactful as people can create memories for information they read
Media and Misinformation; Loftus and Banaji 1989
Showed participants a short video (4 mins) of a robbery and shooting
Then participants were exposed to either a TV report containing misinformation or no misinformation (that was either consistent or inconsistent with the informaiton in the original stimulus video).
Participants were asked to watch the TV report and evaluate the news caster before they were tested for memory on information in the original stimulus video.
Those exposed to a misinformation filled news caster video were more likely to incorporate misinformation . In fact 1/3 of misinformed participants incorporated the misinfo in their reports, whilst control responses were highly accurate
Co-witness discussions; Paterson and Kemp 2006
85% of witnesses engage in co-witness discussions (often before the police arrive)
According to witnesses, the primary purpose of these discussions is to ‘provide/exchange info’
Why are Co-witness discussions bad for the justice process?
“What a court wants is the independent recollection of the individual witness” - Heaton Armstrong 1987
Co-witness discussions means reports are not independent but a collation of multiple witnesses perspectives which may have originally differed
Possible Advantages to Co-witness discussions (Patterson and Kemp, 2005)
- May prompt a witness to recall forgotten details
- May reinforce memory
- May aid recovery from trauma
- May paint a more accurate overall picture
(these advantages are speculated by police generally)
Possible Disadvantages to Co-witness discussions (Pattern and Kemp 2005)
- May contaminate independant recollection (stressed to be of importance by Heaton-Armstrong)
- May weaken the prosecution case
- Witnesses may become unsure of their testimony
- May lead to reports of ‘common things’
- Collusion
Oklahoma Bombing and Co-witness Testimony
In 1995 an apartment building was blown up by a bomb in a rented truck. When tracking back the rental, the owner of the rental company said he remembered loaning the car to two men (however, the two women working in the office said they only remembered one person). Police began looking for two culprits until the rental car owner said he had misremembered and it was only one person who rented the car.
Interestingly, the two women who remembered correctly at the beginning, after hearing their boss admit to only one person having rented the car, felt convinced it was actually two people
Soloman Asch - Conformity Studies
The Solomon Asch paradigm involved presenting a stimulus line, followed by 3 test lines - participants are asked to match the stimulus line to the test line that is of the same length.
In a staged event, participants would do this task in front of a number of confederates, who would intentionally answer wrong (unanimously)
Asch found, participants would alter their response and choose the wrong answer to match the confederates 37% of the time
The conformity response reduced, when there were 2 participants in the group of confederates and when participants were asked to write their answers on paper instead
What are the types of conformity resulting from Solomon Asch’s paradigm
Informational conformity = when a participants gives the wrong answer (the answer that matches confederate responses) as they believe they must be wrong, if the rest of the group is correct
Normative conformity = when a participant knows the answer they’re giving is wrong but they don’t want to disagree with the group
Based from Asch’s findings on Conformity, what can be expect about conformity in the legal system?
As witness interviews are generally done one on one, it’s likely there isn’t a large normative conformity effect. However, due to witness statements being a memory test of sorts, there is likely to be less confidence in information recall anyways - so likely to be a high informative conformity effect if other witnesses have different reports