Reliability Of Eyewitness Testimony

Question 1

Two models of recognition

Answer 1

Recollection - intentional, conscious, affected by attention

Familiarity- automatic, conscious, not affected by attention, supports priming

Question 2

Susceptibility of memory; changing an existing memory

Answer 2

1) following exposure to post event information (the misinformation effect)
2) after discussing memories with a co witness (the memory conformity effect)
3) after suggestive questions in an interview or when cross examined in court (interrogative suggestibility)

Question 3

Why is our memory susceptible to misinformation?

Answer 3

Memory is not a passive store or an exact replica of original events

Humans are best adapted for acquiring knowledge- not providing verbatim accounts

Memory is reconstructive

Question 4

Exposure to Post Event Information

PEI

Answer 4

Study phase: participants exposed to an event

Misinformation phase: after a period of time, half the participants receive misleading PEI (misinformation) about the event, e.g. They could be asked to read a narrative about the event that contains errant details.

Test phase: participants are given a memory test about the originally encoded information.

Question 5

The misinformation effect

Answer 5

Misled participants often report the suggested misinformation at test, even when they have been asked to recall the original details of an event

Question 6

Why do we report Post-Event Information at test

Answer 6

Trace alteration

• original memory trace is overwritten
• creates some kind of memory blend

Trace Blocking
- access to original memory is blocked by the suggested information

Source monitoring
- confusion about source of memories

Social demand
- PEI is reported at test due to processes operating at the time of retrieval, such as task demands or a motivation to be accurate.

Question 7

Loftus 1978

Answer 7

Participants view slides:

• car turns right at intersection and hit pedestrian
• half see a stop sign, half see a yield sign.

Misinformation phase:
Participants hear a narrative describing the accident which is either consistent or misleading.

Test phase:
Recognition tests for slides

Results:
Critical slides to test for misinformation effect (stop vs yield)
75% of control participants chose correctly
Only 41% of misled participants were correct

Question 8

McCloskey & Zaragoza 1985

Critique

Answer 8

Criticise Loftus’ methodology
- the final test does not allow the researchers to draw the bold conclusions that were made about misinformation overwriting an original memory trace

Suggests different interpretations of the data, that do not necessarily imply trace alteration

• both traces exist, but participants select the misinformation because they feel obliged, or trust the experimenter more than own memory.
• the initial detail was never encoded, so participants select the misinformation as its the only familiar option.

Question 9

McCloskey & Zaragoza’s 1895

Answer 9

Believed that misinformation was due to the influences through reports of subjects who never encoded the original event. Subjects would be lured into producing the misinformation, and after deliberation conclude it to be correct.

Participants viewed a yield sign
Half the participants hear about the car passing a stop sign, the other half heard that it’s a yield sign.

Yield vs. Stop sign. 35% drop in accuracy for participants exposed to misinformation.

Yield v NO U TURN sign = high accuracy, and no difference in accuracy between conditions n

This methodology controls for response biases and task demands by excluding the misinformation item as a response choice.
If original memory trace was overwritten, performance would end at chance, performance would be at chance for the misled participants

Question 10

The misinformation effect summary

Answer 10

To fully understand how suggestible our memory is, it is vital to design well controlled experiments

Recent eye witness research, employing valid methodological procedures, supports the view that both the original information and the PEI coexist in memory.

People sometimes errant lay report post-event at test when the information is available

Question 11

Okado & Stark 2005

Answer 11

Standard three stage procedure

Man stealing a girls wallet.
Next some subjects got some misinformation about the event, such as the fact that the girls arm was hurt in the process rather than her neck.
Subjects asked to remember what they saw, many claimed they saw the misinformation details in the original event.

The misinformation was remembered as being part of the original event about 47% of the time.

Robust impairment of memory was produced by exposure to misinformation - the misinformation effect.

Question 12

Okado & Stark 2005

Neural activity

Answer 12

They went on to show neural activity that occurred while the subjects processed the events and later the misinformation predicted whether a misinformation effect would occur.

Question 13

The when question

Greater susceptibility to misinformation

Loftus 1978

Tousignant 1986

Answer 13

Loftus 1978: People are particularly prone to having their memories affected by misinformation when it is introduced after the passage of time has allowed the original event to fade.

Reason: event memory is weakened, less likelihood that a discrepancy is noticed while the misinformation is being processed.

Tousignant 1986: proposed a fundamental principle in determining when changes in recollection after misinformation would occur: the discrepancy detection principle.

Question 14

Assefi & Garry 2002

Scoboria 2002

Answer 14

Temporarily changing someone’s state can increase misinformation effects.
If people are good they have drank alcohol they are more susceptible.

When people are hypnotised they are more susceptible

Effects people’s abilities to detect discrepancies

Question 15

Warning

Greene 1982

Eakin 2003

Answer 15

A warning given after misinterpretation had been processed did not improve ability to resist the misinterpretation effect.

Misinterpreted information had already been encore rated into the memory and altered memory now existing in the mind of the individual.

When people get a warning they suppress the misinformation and it has less ability to interfere.

Suppression may have more trouble when misinformation is too accessible.

Question 16

Ceci & Bruck 1993

Karpel 2001

Answer 16

Younger children are more susceptible to misinformation than are older children and adults

Elderly are more susceptible than are younger adults

Effect of age may present an idea of cognitive resources, as misinformation effects are stronger when attentional resources are limited.

Question 17

Personality variables and susceptibility

Answer 17

The more one has self reported lapses in memory and attention, the more susceptible one is to misinformation effects.

Question 18

Electrophysical studies

Answer 18

Sensory activity is greater for true recognition than false recognition

The hippocampus and a few other cortical regions come into play when people claim to have seen tags they did not see

Question 19

Suggestible because they want thief report to be correct

Hardin & Higgins 1996

Allan 2012

Allan & Gabbert 2008

Answer 19

Individual doubts their accuracy of this own memory of when the information encountered from another individual convinces them that their initial judgement might be wrong.

Those who believe they have inferior memory quality to others were more likely to become influenced by, and subsequently report items of errant PEI encountered for another person.

Overt confidence with which individuals make their assertions to each other can operate systematically as a cue that promotes conformity

Question 20

Emotion & suggestibility

Jacobs & Nadel 2006

Roozendal 2000

Gabbert & Hope 2016

Answer 20

Emotionally arousing events are generally remembered better than natural events.

Stress hormones can enhance memory performance

High stress levels experienced in naturalistic settings generally impairs memory and these detrimental effects have been well documented

Question 21

Suggestibility & stress during encoding

Morgan 2013

Answer 21

Increased level of suggestibility have been associated with stress at encoding.

800 soldiers taking part in survival training. Found those following a high stress interrogate were 40% more likely to identify the person shown at misinformation phase as their interrogator than those who did not receive this information.
27% soldiers mistaken to report their interrogator threatened them with a weapon.

Question 22

Intoxication & memory

Answer 22

Basic research on effects of alcohol on memory tend to show memory impairment.

Lab study: found intoxicated witnesses were no less accurate or vulnerable to suggestion than sober witnesses in their recall of staged events in a lab based study.

Field study: although accuracy did not differ, significantly less information was provided.

Also found alcohol intoxication impaired memory and increased susceptibility to suggestive questions during an immediate interview.

Question 23

Suggestibility & alcohol

Gudjonsson, Hannesdottir 2002

Answer 23

High rates of drug and alcohol intoxication associated with false confessions.

Subjects experiencing withdrawal symptoms may be particularly vulnerable to suggestion and false confession.

Question 24

Working memory suggestibility

Jaschinski & Wentura 2002

Answer 24

Working memory capacity relates to the effect of misinformation on memory.

Found participants with a large working memory capacity were less susceptible to the misinformation.
May be because people with greater memory capacity build a coherent mental model of events during the encoding phase.
Thus they are able to reject misinformation because they recognise it contrasts with their own memory, or because their mental model represents the event is already detailed so additional information is ignored.

Been found working memory capacity negatively associated with suggestibility.

Question 25

Discussing memories with a co witness

Answer 25

Crimes often have more than one witness

86% surveys found witnesses admitted to they had discussed the event with co witness before being interviewed by the police

Question 26

Why report unseen information

Normative motivations to conform

Informational motivations to conform

Memory distortion

Answer 26

Normative: reflects a need for social approval, and a manifest as public declarations of agreement despite private disagreement

Informational: Reflects a desire to be accurate, arises when the correct answer is ambiguous.

Memory distortions: information suggested by anther person becoming over time part of an episodic memory. People can only remember seeing information which they only heard from another eyewitness.

Question 27

Gabbert, Memon & Allan 2003

Answer 27

Participants watched the same mock crime event from different eyewitness perspectives. Found that a significant proportion 71% of participants who had discussed the event reported at least one or two erroneous detail acquired during the discussion of their partner. No age related differences (18-30).

This may be possible social and cognitive mechanisms underlying the distortions of memory due to conformity.

Low ecological validity, due to misleading PEI was controlled, type of information imparted.

Question 28

Hope 2008

Answer 28

We are more likely to conform to our friends than a stranger, which makes us think our memory must be adaptive

Question 29

Principe & Ceci 2002

Answer 29

Investigated memory conformity in children
Staged a classroom based archeological dig for three groups of preschool children.
3 main conditions;
- target group (witnessed archeological dig and finding being destroyed)
- classmate group (did not witness either of these)
- control
The children were interviewed in either a neural or suggestive manner on three occasions. Results from the fourth interview by a new experimenter revealed that the combination of suggestive interviews and peer exposure led to claims of witnessing the target activities by the classmate group that were comparable to the children who actually did witness these activities.
Misleading questions and employing peer pressure and false claims of actually seeing vs hearing about the target activities were elevated following opportunities with to discuss these activities with peers.

Question 30

Martin & Gabbert 2011

The visual partner paradigm

Answer 30

3 households depicting busy household scenes. Participants told that their encoding duration would be half their partners.
Perceived encoding manipulation and then presented forced choice questions.

Response from partner was shown, and it was found that perceived encoding duration only affects memory conformity in the shortest encoding duration condition.

Reliance on other peoples memory is dynamically and strategically adjusted according to knowledge of the conditions under which we and other people have acquired different memories.

Question 31

Memory conformity

Hebert & wheeler 2017

Answer 31

When people discuss their memories they can influence each other’s such that their subsequent individual memory reports become similar.

Question 32

Paterson & Kemp 2006

Answer 32

People are more suggestible when post event information is encountered directly from a co witness

Question 33

Meade & Roediger 2002

Answer 33

Participants were more likely to make source- misattribution errors for items of misinformation encountered from a co -witness, reporting that they could remember seeing items that they had in fact only been suggested.

Gabbert 2004: possible that information encountered during face to face interaction is attended to more fully and deemed to be more credible than information from an absent and anonymous source. This might encourage more active and deeper processing of the information, making it more difficult to later discriminate from the originally encoded information.

Question 34

People may conform to another persons memory due to;

Answer 34

Not wanting to disagree with the other person

Thinking the other person is right

Having a constructed memory based on what the other person said (due to memory distortion or a source attribution).

Question 35

Source monitoring

Answer 35

Source monitoring refers to the decision by process by which memories are discriminated against one another in order to make attributions about the source of these memories.

Question 36

Johnsson 1993

The source monitoring framework

Answer 36

Source monitoring is based on the qualities of experience resulting from combinations of perceptual and reflective processes, usually requires relatively differentiated phenomenal experience, and involves attributions varying in deliberateness.

These judgements evaluate information according to flexible criteria and are subject to error and disruption.

Question 37

Source monitoring decisions can also be made through controlled deliberate strategies such as;

Answer 37

Retrieval of additional information

Supporting memories

Extended reasoning about whether memory is plausible

Question 38

Source monitoring errors

Answer 38

Being able to recall memory does not guarantee its authenticity

Source monitoring errors can occur when the heuristic judgement process, based in the expected memory characteristics is wrong.

This can occur when the qualities associated with memory from each source are similar.

Question 39

Lindsey 1990

Answer 39

136 American students
79 colour slides, man steals money and a calculator from an office.
Tape recorded voice accompanied slides with description of events.
Post event information was the narrative

Low discriminability: female voice, participants listened to second description immediately following the slide show. The recording was in the same voice as had accompanied the slides.

High discriminability: male voice. Participants listened to second description 48 hours after the slide show. In a different room and a different voice.

Participants told to disregard information in the second description because it was wrong.

Results: a misinformation effect was only apparent in the ‘low discriminability’ condition because participants found it difficult to discriminate the source of their memories.

Participants in high discriminability condition took advantage of the differences in the memory characteristics accompanying the original information and the PEI.