Eyewitness Testimony Flashcards
The weapon-focus effect
This is where in violent crimes, arousal may focus the witness on more central details of the attack (eg: weapon) than the more peripheral details (eg: what else was going on and what the perpetrator looked like).
YERKES-DODSON LAW (1908)
- The relationship between emotional arousal (anxiety) and performance is an inverted U.
- There is an optimal level of anxiety needed for accurate recall.
Christianson & Hubinette 1993
- Questioned real victims of a bank robbery. They found that those who had actually been threatened were more accurate in their recall, compared to those who were onlookers. This continued to be true 15 months later.
What was the procedure of Lotfus and Palmer 1974 on misleading questions?
- 45 students shown 7 films of traffic incidents
- Students were given questionnaire
- There was one critical question about how fast the cars were going - each with a different verb
- collide, hit, bump, contacted, smashed
Johnson & Scott (1976):
- Participants believed it was a lab study
- The low anxiety group heard a casual conversation then a man walking out with a pen and greasy hands
- The high anxiety group heard a heated argument followed by the sound of breaking
glass then a man walked out with a bloody knife
Johnson & Scott (1976) findings and conclusions
- The participants then had to pick out the man from 50 photos
- 49% who saw the man holding a pen could pick him out
- 33% who saw the man holding the bloody knife could pick him out
- Tunnel theory suggests that people have enhanced memory for central events; weapon focus as a result of anxiety can have this effect
Yuille & Cutshall (1986):
- Study of an actual shooting in a gun shop in Vancouver
- Shop owner shot their dead
- There were 21 witnesses and 13 took part in the study
- Interviewed 4-5 months after event
- Interviews compared to real police interviews months prior
- Accuracy determined by number of details reported
- They had to rate how stressful it was on 7-point scale and if they had emotional
damage
Yuille & Cutshall (1986) findings and conclusions
- Participants were accurate in their accounts
- Some details were less accurate such as colour of items
- Participants with highest stress levels were most accurate (88% compared to 75% of
less stressed group) - This suggests that anxiety does not have detrimental effect on the accuracy of
eyewitness memory in real world
What did Deffenbacher et al 2004 discover for EWT?
It was a meta-analysis which found that high levels of stress impacted on the accuracy of EWT.
What is misleading information?
Incorrect information given to an eyewitness usually after the event (hence often called post-event information’). It can take many forms, such as leading questions and post- event discussion between co-witnesses and/or other people.
What were the findings discovered by Lotfus and Palmer with misleading questions?
The mean estimated speed was calculated for each participant group. - The verb contacted resulted in a mean estimated speed of 31.8 mph.
- For the verb smashed, the mean was 40.5 mph. The leading question biased the eyewitness’s recall of an event
What procedure did Gabbert et al use when studying post-event discussion?
- Fiona Gabbert et al. (2003) studied participants in pairs. Each participant watched a video of the same crime, but filmed from different points of view.
- This meant that each participant could see elements in the event that the other could not. For example, only one of the participants could see the title of a book being carried by a young woman
- Both participants then discussed what they had seen before individually completing a test of recall.
What were the findings Gabbert et al discover when studying post-event discussion?
- The researchers found that 71% of the participants mistakenly recalled aspects of the event that they did not see in the video but had picked up in the discussion.
- The corresponding figure in a control group, where there was no discussion, was 0%. This was evidence of memory conformity.
Why does post-event discussion affect EWT?
- One explanation is memory contamination. When co-witnesses to a crime discuss it with each other, their eyewitness testimonies may become altered or distorted. This is because they combine (mis)information
from other witnesses with their own memories. - Another explanation is memory conformity. Gabbert et al. concluded that Witnesses often go along with each other, either to win social approval or because they believe the other witnesses are right and they are wrong
- Unlike with memory contamination, the actual memory is unchanged.
What is the real-world application of study into misleading information?
- One strength of research into misleading information is that it has important practical uses in the criminal justice system.
- The consequences of inaccurate EWT can be very serious. Loftus (1975) believes that leading questions can have such a distorting effect on memory that police officers need to be very careful about how they phrase their questions when interviewing eyewitnesses. Psychologists are sometimes asked to act as expert witnesses in court trials and explain the limits of EWT to juries.
- This shows that psychologists can help to improve the way the legal
system works, especially by protecting innocent people from faulty convictions based on unreliable EWT.
What are the four aspects of cognitive interview?
- Report everything
- Reinstate the context
- Reverse the order
- Change perspective
What is reporting everything in cognitive interviews?
- Witnesses are encouraged to include every single detail of the event, even though it may seem irrelevant or the witness doesn’t feel confident about it. Seemingly trivial details may be important and, moreover, they may trigger other important memories.
What is reinstating context in cognitive interviews?
- The witness should return to the original crime scene ‘in their mind” and imagine the environment (such as what the weather was like, what they could see) and their emotions
[such as whether they were happy or bored). - This is related to context-dependent forgetting.
What is reversing the order in cognitive interviews?
- Events should be recalled in a different order from the original sequence, for example, from the final point back to the beginning, or from the middle to the beginning.
- This is done to prevent people reporting their expectations of how the event must have happened rather than reporting the actual events.
- It also prevents dishonesty (it’s harder for people to produce an untruthful account if they have to reverse it).
What is changing perspective in cognitive interviews?
- Witnesses should recall the incident from other people’s perspectives. - For example, how it would have appeared to other witnesses or to the perpetrator. This again is done to disrupt the effect of expectations and also the effect of schema on recall.
- The schema you have for a particular setting (such as going into a shop) generate expectations of what would have happened and it is the schema that is recalled rather than what actually happened.
