Factors affecting EWT Flashcards
What is EWT?
Recollection of an event by a witness, usually a significant period of time afterwards
What are leading questions?
A question that influences the individual to give an answer that is desired by someone and not necessarily what happened. A question which, because of the way it is phrased, suggests a certain answer.
For example: ‘Was the knife in the accused’s left hand?’. This suggests the answer is ‘left hand’.
What is post-event discussion?
Discussion with others after the event can also have an effect on memory
What did Loftus and Palmer (1974) find?
150 Washington state university students were split into 3 groups. All groups watch a 1 minute video of a car accident and then given a questionnaire to complete.
Condition 1 - “How fast were the cars going when they hit each other?”
Condition 2 - “How fast were the cars going when they smashed into each other?”
Condition 3 - Control - not asked
Asked to come back in one week and then asked “did you see any broken glass?”
Condition 1 - 14%
Condition 2 - 30%
Condition 3 - 12 %
What did Yuille and Cutshall (1986) find?
21 witnesses observed a shooting incident in which 1 person was killed and a 2nd seriously wounded. The incident took place on a major thoroughfare in mid-afternoon. All of the witnesses were interviewed by the investigating police, and 13 witnesses (aged 15–32 yrs) agreed to a research interview 4–5 mo after the event. In the present study, the eyewitness accounts provided in both the police and research interviews were analyzed. The witnesses were highly accurate in their accounts, and there was little change in amount or accuracy of recall over 5 mo. However, some aspects of color memory and age, height, and weight estimations were found to be erroneous. The eyewitnesses resisted leading questions, and their stress levels at the time of the event appeared to have no negative effects on subsequent memory. The findings above imply that laboratory findings about leading questions and EWT may be inaccurate.
Factors in post event discussion that can effect EWT?
- Retroactive interference/media coverage
- Conformity
- Repeat interviewing
What is retroactive interference/media coverage as a factor of post event discussion?
Information currently present in the media interferes with the recall of past events e.g. discussing events with other people e.g. most countries do not allow pre-trial media coverage because of this.
What is conformity as a factor of post event discussion?
Normative - Changing opinions to fit in with the group e.g. if your friends are discussing events
Informational - Changing opinions because if a police or a lawyer that we view as experts suggest misleading information during post event discussion then we will internalise this and genuinely believe them leading to altered memory
What is repeat interviewing as a factor of post event discussion?
Due to the reconstructive nature of memory, many psychologists believe that repeated interviewing could potentially damage the original memory of events. Interviewed by the Police, potentially more than once, and then in a court of law could create subtle differences in recall of events. Usefully, the Police tend to record all interviews carefully to help minimise this risk of RECONSTRUCTIVE ERRORS.
What did Gabbert et al (2003) find?
Investigated the effect of post-event discussion by asking 120 ppts to watch a video of a girl stealing money from a wallet. The ppts were either tested individually (control group) or in pairs (co-witness group where they had actually seen different perspectives of the same crime where one saw the girl steal the money and one didn’t). The cowitness group were allowed to discuss the video afterwards. Gabbert found 71% in the co-witness group recalled information they had not actually seen and 60% said she was guilty despite not seeing her commit a crime.
What is anxiety in relation to EWT?
Witnesses may be in a state of high arousal. This will be particularly likely if there is threat or danger or if the witnesses may have a naturally more anxious personality
What is the Yerkes-Dodson law?
Suggests that performance and arousal are directly related. In simpler terms, increase in arousal to a certain level can help to boost performance. Once the arousal crosses the optimal level, performance of the individual starts to diminish
What is the weapon focus effect?
If a witness is anxious due to a threat, they may remember more about the thing that poses the threat and less about the other details and there may be difficulty recalling information about other factors, such as the description of the offender etc.
What did Loftus and Burns (1982) find?
The study had two conditions: one violent and one non-violent. In both conditions Pt’s saw a video of a bank robbery
- One group of participants a film of a crime with no violence.
- Another group were shown the same film but with a violent incident (a boy was shot in the face).
Those who saw the violent incident recalled significantly less than those who saw the film without the violent incident: suggesting that the anxiety caused by the violence negatively affected recall.
What did Johnston and Scott (1979) find?
The study aimed to see if anxiety would damage EW identification. In one of two conditions Pts, i) overheard a low key discussion in a lab about equipment failure. A person then emerged from the lab holding a pen in grease covered hands; or ii) overheard a heated and hostile debate between people in the lab. After the sound of breaking glass and crashing chairs, a man came out of the lab holding a letter opener covered in blood. Pt’s were then asked to recall the person from 50 photos. 49% correctly recalled the man when he was holding a pen compared to just 33% when he was holding the letter opener, weapon.
