EWT Flashcards
Eye witness testimony
The ability of a person to remember details of an event they have observed
Mainly used for crimes / accidents
Accuracy of EWT can be affected by leading questions + anxiety and other factors
What is a leading question
A question in which, because of the way it is
phrased, suggests a certain answer.
These can have a negative effect on EWT and can seriously alter accuracy of a persons recall of events
Loftus + palmer 1974 procedure
45 students.
Shown video clips of road traffic accidents. After each clip Ps asked to give an account of the accident.
They were then split into 5 groups with 9
participants in each group.
All of the participants were asked: ‘About how fast were the cars going when they ________ into each other’ (smashed, hit, bumped etc)
Participants estimates were recorded in miles per hour (mph)
Loftus + palmer findings
Smashed - estimated 40.8 mph
Collided - estimated 39.3 mph
Bumped - 38.1
Hit - 34
Contacted - 31.8
Leading questions clearly influence perception of speed with participant speed estimates for the word ‘smashed’ being almost 10mph faster than for the word ‘contacted’
Why do leading Qs affect EWT
1. Response bias
The wording of a question has no real effect on a persons memories but just influences how they decide to answer
When a participant gets a leading question with ‘smashed’ it encourages them to estimate a higher speed
Why do leading Qs affect EWT
2. substitution
the wording of a question actually changes a person’s memory of an event
it will alter the way we remember the event affecting the way we might give an EWT.
loftus + palmer follow up study
150 students watched a short video (multi car accident)
Ps split into 3 groups - 50Ps each
group 1 - “how fast were they going when they hit each other?”
group 2 - how fast were the cars going when they smashed into each other
group 3 - not asked about speed of vehicles
followed up after 1 week - “Did you see any broken glass?” - there wasn’t any!
loftus + palmer follow up study findings
16 people who said yes were asked using the word smashed
44 people who said no were in the control group
what is post event discussion
occurs when there is more than 1 witness to an event
those who have observed the event will discuss what happened with other co-witnesses
post event discussion can influence accuracy of EWT
Gabbert et al procedure
Pairs of participants - each watched video of the same crime from different POV so they may see things that others didn’t.
Pairs were able to discuss what they had witnessed before carrying out a recall test of the event seen in the video
Gabbert et al findings
71% of eyewitnesses who had discussed the crime made mistakes when recalling the events
no discussion - 0% of mistakes in recall were made
This suggests that PED can lead to inaccurate eyewitness testimony
Strength of misleading info - useful
P: research into the effects of misleading information has been useful.
E: This research has been useful in developing questioning techniques e.g. Cognitive Interview that the police will use when gathering EWT. It attempts to minimise the use of leading questions for example, so you are more likely to gather a reliable EWT.
C: if info is wrong then correct offender may or may not be convicted
Strength of misleading Qs - lab exp
P: studies that support misleading Qs on EWT is that they are conducted in a lab - Loftus + palmer
E: EVs can be controlled. Use of standardised procedures eg. All Ps watch the same video
C: this allows a C+E relationship to be established eg. more aggressive word eg smashed causes a higher estimated speeds. Standardised procedures increases reliability.
Limitation of misleading info - tasks given
P: can criticise tasks used in supportive studies eg Loftus + palmer
E: Ps were asked to estimate speed of car after watching a video clip. However in real life anxiety could affect EWT so your estimate speed may differ. PED could also happen.
C: this means it lacks ecological validity. So we can’t generalise findings real life so you don’t know much about EWT in real life
limitation of studies supporting misleading info - conducted in lab
P: eg. Loftus + Palmer
E: artificial environment so Ps may display demand characteristics. Eg. by paying more attention to the video
C: can’t generalise findings as they lack validity. Might not tell us how EWT works in everyday life.
anxiety
a state of emotional & physical arousal.
Emotional: worried thoughts/ feelings of tension.
Physical: increased heart rate/sweatiness.
anxiety - negative effects on recall
Johnson & Scott (1976)
P’s thought they were taking part in a laboratory study- seated in a “waiting room”
P’s heard an argument coming from the next room.
Condition 1(low anxiety group)- a man left the room with a pen & grease on his hands.
Condition 2 (high anxiety group)- a man left with a knife and blood on his hands.
Had to identify the man from a set of 50 photos.
Johnson & Scott (1976)
findings
33% of P’s in the high anxiety group could correctly identify the man with a knife & blood on his hands.
49% of the P’s in low anxiety group could correctly identify the man with a pen & grease on his hands.
Tunnel theory & Weapon Focus: witnesses’ attention is drawn towards the weapon, as it’s a source of anxiety.
anxiety - positive effects on recall
linked to fight or flight response- makes us more alert/improves memory
Conducted a study of a real life shooting in Vancouver- the shopkeeper shot the thief dead!
13 witnesses agreed to take part in study.
Interviewed 4-5 months after event- compared to their original accounts at time of incident.
Also asked to rate stress levels and if they had experienced any emotional problems since.
Yuille & Cutshall (1986)- findings
Witnesses were very accurate in their accounts- little change in accuracy levels.
Those who reported highest levels of stress were most accurate (88% most stressed vs. 75% for less stressed).
Supports the idea that anxiety can have a positive impact on recall of events.
Yerkes - Dodson law = ‘inverted U’
Link between emotional state & performance.
Lower levels of anxiety= lower EWT accuracy.
Memory becomes more accurate, as anxiety increases until it reaches an optimal point. This is when EWT are most accurate.
However, there becomes a point in which the anxiety levels become too high and accuracy begins to reduce.
strength of anxiety - supportive studies conducted in lab
P: eg. Johnson + Scott
E: high control of EVs and could use standardised procedures eg. in 1 condition there was always the same man holding the knife
C: can establish C+E relationship eg. higher anxiety, lower accuracy. Standardised procedures increases reliability.
limitation of anxiety - Johnson & Scott conducted in lab
artificial environment - doesn’t reflect real world
results lack ecological validity so can’t generalise
can’t tell you much about anxiety in real life
limitation of anxiety - studies criticised for breaching ethical issues
E: Johnson & Scott. Here, deception + informed consent breached as Ps thought they were taking part in lab study but then they were asked to identify man with knife. Couldn’t consent as didn’t know what study involved.
C: breached ethical guidelines that have been put in place to protect the right of the Ps.
