eye witness testimony Flashcards
what is weapon focus effect
weapon focus is the tendency for witnesses to violent crimes to focus
their attention on the weapon used. Weapon focus usually results in poor quality testimony, as the witness is unable to describe much that is useful about other aspects of the incident.
give research to support weapon focus effect. how good is the research?
Kohnen (1989) carried out a field experiment in which participants were approach by a woman holding either a pen or a syringe. Participants in the ‘pen’ condition were able to supply more accurate descriptions of the woman. Studies like these give support to the suggestion that witnesses’ attention tends to be drawn towards a weapon,
thereby preventing them from taking in other details about the situation. research is limited as lacks ecological validity as a pen/syringe do not pose a threat to the ppts so will not cause the same reaction as weapon focus.
give another piece of research to support weapon focus effects
Loftus et al (1987) showed participants one of two films. In one, a customer in a restaurant was holding a cheque, in the other he was holding a gun. It was found that participants had a higher recall for the ‘cheque’ condition. high ecological validity as it is carried out it reflects how EWT works in real life conditions.
describe the effect anxiety has on EWT
According to the Yerkes-Dodson Law, an increase in arousal improves performance but only up to a point. Once arousal has passed a critical point called the optimum, performance tends to decline. A possible interpretation of the research on violence distraction is that witnessing violence raises witnesses’ arousal level past optimum, leading to poorer memory performance.
give research to support
Clifford and Scott (1978) found that witnesses to violent incidents generally recall less than witnesses to non-violent incidents, regardless of whether a weapon was used or not. They showed participants one of two films involving the same people. In one film there was a physical assault. Participants who viewed this film were less likely to identify the people involved than those who had viewed the non-violent film. lacks ecological validity as it doesn’t mirror the high levels of stress and anxiety experienced during a real life crime so we cannot establish that this is how EWT works when faced in a real life crime
give a counter argument for critics of EWT
Yullele and Cutshall showed that witnesses of a real-life incident (a gun shooting outside a gun shop in Canada) had remarkable accurate memories of a stressful event involving weapons. A thief stole guns and money, but was shot six times and died.
The police interviewed witnesses, and thirteen of them were re-interviewed five months later. Recall was found to be accurate, even after a long time, and two misleading questions inserted by the research team had no effect on recall accuracy. One weakness of this study was that the witnesses who experienced the highest levels of stress where actually closer to the event, and this may have helped with the accuracy of their memory recall.
what is post event information, give an example of how this can distort recall of memories
Post-event discussion is when eyewitnesses discuss what they saw in an event with each other. This can influence the accuracy of an eyewitness’ recall because the other person’s view could feed them incorrect information.
give research to support post event information. how good is the research?
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 from the other person in discussion. However, the corresponding figure in a control group (where there was no discussion) was 0%. This comparison shows how powerful post-event discussion can be. Gabbert et al. concluded that witnesses often go along with each other, either to win social approval or because they simply believe that the other witnesses are right and they are wrong. however lacks ecological validity as a lab experiment where ppts watched the crime on TV screen so doesn’t represent how EWT works in real life conditions when experiencing high levels of anxiety
what are leading questions
a question that prompts the desired answer ie was there glass on the floor? vs was there anything on the floor? reduce the reliability of EWT.
what is the application of EWT
the delvin report - we cannot solely convict someone of a criminal offence based on EWT alone. the cognitive interview helps to build rapport ie report everything, shift perspective, go back to the scene of the crime in mind to increase EWT and better train interviewers to use less leading questions. at a scene of a crime split witnesses up so that they cant speak with other people
