susceptibilitatea memoriei Flashcards
Do eyewitnesses make mistakes?
Yes.
Misinformation effect- after exposure to post-event information
The memory conformity effect - after discussing memories with a co-witness
Interrogative susceptibility - after suggestive questions in an interview or when cross-examined in court
Why is memory suggestible
Memory is not an exact replica of original events
Memory is reconstructive - details of an incident may be reconstructed according to witness expectations and pre-existing schemata
We are susceptible to inaccurate or misleading information from external sources
- Exposure to post event information PEI
Participants are exposed to an event e.g. a video
Misinformation phase: after a period of time, half the participants receive misleading PEI about the event. E.g. they could be asked to read a narrative about the event that contains errant details
Participants are given a memory test about the originally encoded information
What are the findings about PEI
Misled participants often report the suggested misinformation at test, when when they have been asked to recall the original details of the event
This is the misinformation effect
What is the study of Loftus, miller and burns (1978)
Participants view slides
Car turns right at intersection and hits a pedestrian
Half see stop sign, half see yield sign
Misinformation phase: participants hear a narrative describing the accident which is either consistent or misleading
In test phase they are asked which sign they saw
75% of control participants chose correctly
41% of mislead participants were correct
So the original memory was overwritten by post event information
What are criticisms of this experiment
People select the misinformation because they feel obliged, or trust experimenter more than their own memory
Or maybe the initial detail was never encoded, so people select the misinformation as it’s the only familiar option
What is an experiment that tested the limitations of loftus study (McCloskey and Zaragoza, 1985)
Participants view yield sign
Half the participants hear about the cat passing a stop sign the other half hear that it’s a yield sign
Yield sign vs stop sign - 35% drop in surface for ps exposed to misinformation
Yield sign vs no u turn sign - high accuracy, and no difference in accuracy between controls and ps in misinformed condition
Why do we report post event information
Trace alteration: original memory trace is overwritten
Social demands/response bias: PEI is reported at test due to task demands, or a motivation to be accurate
Source monitoring error
What is source monitoring framework
Source minoring refers to the decision process by which memories are discriminated against one another in order to make attributions about the source of these memories
source-monitoring framework
theoretical account of memory
describes how ppl accurately identify the source of a memory, and why errors can occur
monitoring decisions are based in part on the qualities of retrieved memories:
- vividness
-availability
-temporal information
-associated memories
how do we source monitor
memories acquired from different sources tend to differ in qualitative characteristics
e.g. suggested events typically have less vivid perceptual, emotive, temporal, spatial information than perceived events
source attributions are often made automatically using heuristic-based decisions
e.g. if a memory comes to mind quickly and vividly it is often assumed to be true
source-monitoring decisions can also be made through more controlled and deliberate strategies such as
- retrieval of additional information
- supporting memories
- extended reasoning about whether a memory is plausible
source monitoring errors
being able to recall a memory does not guarantee its authenticity
source-monitoring errors can occur when the heuristic judgement process, based on the expected memory characteristics, is wrong
this can occur when the qualities associated with memory from each source are similar
research shows that the harder it is to retrieve specific source-information, the more we make source-monitoring errors
Lindsay (1990)
participants viewed a slide show
misinformation phase. post-even information was presented in a subsequent audio description of the event. there were 2 conditions:
low discriminability conditionL ps listened to second description immediately following slide show. the recording was in the same voice as had accompanied the slides
high discriminability condition: ps listened to second description 48 hrs after the slide show. the was presented to ps in a different part of the room, and in a different voice to the original recording
ps told to disregard information in the second description of the slides because it was wrong
a misinformation effect was only apparent in the low discriminability condition because ps found it difficult to discriminate the source of their memories
ps in high discriminability condition took advantage of the difference in the memory characteristics accompanying the original information and the PEI
Horry, Colton and Williamson (2014)
examined the effect of retention interval on a person’s ability to accurately identify the source of their memory
ps viewed a videotaped staged crime event and read a misleading narrative about it
manipulated the duration of time before a cued-recall test about details of the original event (7minutes vs 7 days)
before completing the memory test, all ps were warned that the narrative contained misleading details (to encourage source monitoring)
observed a large effect of retention interval on discrepancy detection and a person’s ability to accurately identify the source of their memory
the strength of the confidence-accuracy relationship declined significantly over the delay
after the extended delay, fewer diagnostic source details were available to ps, increasing reliance on retrieval fluency as a basis for memory and metamemory decisions
secure eyewitness statements as soon as possbile, when witnesses are best able to discriminate between information that was personally seen and post-event information
Suggestibility and the misinformation effect: summary
to fully understand how suggestible our memory is, it is vital to design well controlled experiments
recent eyewitness research, employing valid methodological procedures, supports the view that both the original information and the PEI co-exist in memory
ppl sometimes errantly report post-event information at test even when the original information is available
- this often happens because of a source-monitoring error
- discussing memories with a co-witness
over half of a UK survey of real eyewitnesses and 86% of a similar Australian survey found witnesses admitted they had discussed the event with a co-witness before being interviewed by the police
remembering with other people
a single shared account is often sought after and established
collaborative remembering can lead to memory conformity
why report information from someone else
normative motivations to conform - reflects a need for social approval, and manifest as public declarations of agreement despite private disagreement
informational motivations to conform - reflects a desire to be accurate; arises when you don’t know the correct answer
source confusions and memory distortion - information suggested by another person becoming, over time, part of an episodic memory. ppl can remember seeing information which they only heard from another eyewitness
can eyewitnesses influence each other’s memories for an event (Gabbert et al, 2003)
120 ps
2 (young adults, older adults) x 2 ( co-witness dyads, control)
investigated memory conformity effects between individuals who witness and then discuss a criminal event
each member of a dyad watches a different video of the same event
each video contained unique items that were thus seen only by one witness
dyads in one condition were encouraged to discuss the event before each witness individually performed a recall test
in a control condition, dyads were not allowed to discuss the event prior to recall
a significant proportion (71%) of witnesses who had discussed the event went on to mistakenly recall items acquired during the discussion
no age related differences in susceptibility to these memory conformity effects in younger (18-30) compared to older (60-80) ps.
Hope et al 2008
we are more likely to conform to our friends than stranger
suggests memory conformity might be adaptive
evidence for source-monitoring errors?
Gabbert et al 2007
ps viewed 4 slides of different scenes
2 versions of each slide
2 critical items unique to each version
ps discussed the slides prior to providing an individual account of what they had seen
ps were given a source monitoring task where they were asked to review their accounts
a. circle the details that they had remembered hearing from their co-witness, but not actually seeing themsleves
b. leave unmarked the details that they did remember seeing in the slides
underline the details for which they could not remember the source
of the post-event information reported at test, approximately half were correctly categorised as having been encountered in the co-witness discussion.
however, the other half were incorrectly attributed to having been seen in the original slide presentation
evidence for source-monitoring errors (Paterson et al 2009)
similar study
ps were asked to attribute the source of their statements to one of four sources - video only, discussion only, both the video and discussion, or unsure
ps frequently reported that they had seen items of post-event information that had in fact only been suggested to them in the co-witness discussion
accurate source monitoring decisions were made 43% of the time
- interrogative suggestibility
interviewers can sometimes suggest things to an interviewee that they had not mentioned themselves (post-event information)
- using leading questions
-revealing details about the case
this can change what an interviewee subsequently reports
children are particularly vulenrable to interrogative suggestibility
- more likely to acquiesce
- more likely to trust adults, especially those in a position of power
case study: McMartin Preschool, Manhattan Beach, CA
August 1983, a parent tells police her son was molested by Ray Buckey
letters were sent out to parents of past and present students which caused panic
soon, over 300 children were thought to have been abused, 100’s of interviews conducted
Buckey was arrested and served 5 years in prison waiting for the trial
the court case took 6 years
wild allegations leading to over 300 charges of child abuse against Buckey and 6 colleagues
Huge media attention with reports of a child sex ring in LA
hundreds of children believed they were victims of abuse
but no evidence - the case was eventually closed with all charges dismissed
