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factors affecting accuracy of eye witness testimony - Coggle Diagram
factors affecting accuracy of eye witness testimony
Eyewitness testimony refers to the description given by people of an event they have experienced, including that given in a criminal trial by individuals present at the time of the crime. It includes the identification of people as well as details such as speed of vehicles, weather conditions etc.
misleading information
leading questions
Loftus&palmer- investigated effect of leading questions on accuracy of EWT .used sample of American students. All participants watched a video of a car crash and were then asked specific question about the speed of the cars. manipulated verb used in the question, for example: “How fast were they cars going when they smashed/ collided/ bumped/ hit/ contacted with each other?” found the estimated speed was affected by the verb used. For example, participants who were given the verb ‘smashed’ reported an average speed of 40.8 mph, whereas participants who were given the word ‘contacted’ reported an average speed of 31.8 mph.this shows that the accuracy of EWT is affected by leading questions and that a single word in a question can significantly affect the accuracy of judgement.
strength- research took place in highly controlled lab and reduced extraneous variables meaning causal link can be established between verb used and estimation of speed. high internal validity
limitation- has questionable ecological validity as In everyday reports of car accidents, witnesses rarely see the whole event; they either are involved in the event directly, or see a small part of the event happen in their peripheral vision.Therefore, their results do not reflect everyday car accidents and are unable to conclude if eyewitnesses to real accidents, who would have a stronger emotional connection to the event, would be susceptible to leading questions in the same way
post-event discussion
memory of an event may be altered or contaminated through discussing events with others and/or being questioned multiple times
This occurs because witnesses combine misinformation from other witnesses with their own memories
Gabbert and colleagues
Each ptpt watched a video of the same crime filmed from different points of view.meant that each ptpt could see elements of the event that the other could not see. Pairs in one condition were encouraged to discuss the event with each other before each partner individually recalled the event they watched. In the control group, there was no discussion.
found that 71% of participants in the experimental group mistakenly recalled aspects of the event that they could not have seen but had picked up in the discussion. This compares with 0% in the control group. Gabbert called this memory conformity and suggested that witnesses go along with each other for social approval or because they believe the other witnesses are right and they are wrong.
strength- gabbers tested 2 diff populations of students and older adults and found little difference between the two conditions, suggesting good population validity
limitation-distortion could be the result of poor memory, where people assimilate new information into their own accounts of the event and are unable to distinguish between what they have seen and what they have heard.On the other hand, it could be that the distortion occurs due to conformity and the social pressure from the co‐witness.Therefore, further research is required in the real‐world to demonstrate the exact effect on misleading information on the accuracy of EWT
evaluation
alternative explanation- anxiety levels
real life application- led to the development of the cognitive interview where the police are trained to use techniques such as ‘report everything’ which means that witnesses to crimes are encouraged to describe what they have seen, without interruption from the police officers.means that the police are much less likely to use leading questions, which will improve the accuracy of EWT.
anxiety
Many psychologists believe that anxiety affects the accuracy of eyewitness testimony in a negative way (decreases the accuracy), whilst others believe that anxiety can improve the accuracy of eyewitness testimony.
Deffenbacher
was one of the first to investigate the link between anxiety and EWT and after reviewing 21 studies, he found that accuracy is poor when emotional arousal is either high or low, but is better under conditions of moderate arousal.
Yerkes-Dodson Law
suggests that there is a relationship between performance and arousal. Increased arousal as caused by anxiety can help improve performance, but only up to a certain point. At the point when arousal becomes excessive, performance diminishes. In the context of EWT the Yerkes-Dodson law suggests moderate anxiety is associated with better recall than very high or very low anxiety.
Laboratory based studies have generally shown impaired recall in people who have witnessed unpleasant or anxiety-inducing situations.
Johnson and Scott suggested the participants who saw the knife experienced more anxiety and therefore focused their attention on the weapon, not the face, which is called the weapon focus effect. Therefore, the anxiety associated with seeing a knife reduces the accuracy of eyewitness testimony.
evaluation
methodological issues as Real life research into EWT has limited control, unable to be replicated and issues with confounding variables. For example, in Yuille & Cutshall’s study those who experienced the highest levels of stress were closer to the event, which might have helped their recall.means that there are issues with validity when investigating the effects of anxiety on the accuracy of EWT
has practical applications as when taking EWTs the police need to take into account the witness’s level of anxiety. According to the Yerkes-Dodson law if witnesses are highly anxious they may miss important information.Furthermore, anxiety level should be taken into consideration alongside other factors such as the view the witness had of the crime to increase the accuracy of EWT.
This means that improving the accuracy of eyewitness reporting enables better use of police time and resources which also has economic benefits, such as not wasting the tax payers money on the wrong criminal.
However, other research into real-life incidents involving high levels of stress, have shown that in such situations, memory can be detailed, accurate and long-lasting
Yuille and Cutshall investigated the effect of anxiety in a real‐life shooting, in which one person was killed and another person seriously wounded. ptpts rated how stressed they felt at the time of the incident and then were interviewed again after 5 months. Participants who reported the highest levels of stress were most accurate in their recall about 88% compared to 75% for the less stressed group.These results refute the weapon focus effect and show that in real‐life cases of extreme anxiety, the accuracy of eyewitness testimony is improved.