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Eye Witness Testimony.
Transcript of Eye Witness Testimony.
This happens after the event has taken place. Often, memories from an event are fragile and can be subject to distortion by post event information. It appears that this misinformation can introduce serious errors into the eyewitness's recall of the event.
Loftus called this "misinformation acceptance" - where people accept the misleading information after an event and absorb it into their memory for the actual event. There is a greater tendency to accept post-event information in this way as the time since the event increases.
This has important implications for the ways in which police and lawyers question individuals in criminal investigations.
EYE WITNESS TESTIMONY
Psychologists are interested in EWT because it's a direct account of an event. The quality of an EWT is important as people can be falsely accused and possibly prosecuted for crimes they didn't commit if the following factors affect its accuracy:
When you witness a crime, it is likely that it causes a high level of anxiety at the time, that is, during the encoding stageof the memory process. This can affect the accuracy of the memory.
When considering how reliable an eye witness testimony is, it is important to bear in mind the type of crime being recalled. Some crimes - such as those that include violence - have high levels of anxiety, while others (such as minor traffic offenses) are likely to cause low anxiety.
The Yerkes Dodson Law suggest that performance is related arousal. Too much arousal would be interpreted as stress and anxiety. When seeing a violent crime (high arousal) our performance drops off and our memory is an area that can be affected.
Age in EWT
Encoding: A child's EWT may be inaccurate because they do not have the correct schema (general perception of something). This can make it difficult to encode an event with accuracy.
Storage: As time between encoding and retrieval increases, the accuracy of the event decreases. Although, this happens to both children and adults it is said to happen more in children.
Retrieval: Children tend to leave out more information than adults although clues can help them get more information. However, when a child is asked a leading question they are more likely to give a straight answer.
Aim: to investigate whether misleading information affects the accuracy of EWT after an event.
Method: Loftus showed 150 participants a film of the events leading up to a car accident. After they had seen film, participants were divided into a control group and an experimental group. The contrl group was asked questions consistent with what they had actually seen ("How fast was the white sports car going when it passed the stop sign?) whereas the experimental group was asked questions including misleading information ("How fast was the white sports car going when it passed the barn whilst travelling along the country road?"). There had been a stop sign in the original film but no barn. All the participants were then asked more questions about the accident.
Result: CONTROL: 3% said YES they saw the barn; EXPERIMENTAL: 17% said YES they saw the barn.
Conclusion: Loftus concluded that some of the participants given the misleading information had actually absorbed this with their original memory for the event and now really believed they had seen a barn.
Loftus and Palmer (1974):
Aim: To investigate whether misleading information affects the accuracy of EWT after an event.
Method: 45 participants (students) were shown a film of a car accident and then asked them a series of questions about events leading up to the accident. One crucial question concerned the speed of the car on impact. One group was asked "How fast were the cars going when they hit each other?". The other was asked the same question, but in each case, the verb was changed to either "smashed", "bumped", "collided" or "contacted".
Results: the verb significantly affected the speed estimates - contacted: 31 mph; hit: 34 mph; bumped: 38 mph; collided: 39 mph; smashed: 41 mph. Therefore, smashed produced the highest estimate and contacted produced the lowest. A week later, when questioned again, participants who had been asked the smashed version of the question were more likely to report having seen broken glass at the scene of the accident, even though there had been none.
Conclusion: The misleading words of the questions affected the accuracy of participants' EWT.
The Weapon Focus Phenomenon
Aim: To find out if anxiety during a witnessed incident affects the accuracy of later identification.
Method: Participants were asked to sit outside a laboratory where they thought they were listening to a genuine exchange between two people inside. Participants were exposed to one of two situations:
1: They overheard a low key discussion in a lab about equipment failure. A person then emerged from the lab, holding a pen and with grease on his hands.
2: They overheard a heated and hostile exchange between two people in a lab. After the sound of breaking glass and crashing chairs, a man emerged from the lab holding a paper knife covered in blood.
Results: Participants who had witnessed the more violent scene were less accurate in identifying the man.
Conclusion: Loftus concluded that this was because of the heightened anxiety of the witness in violent scene caused them to focus on the weapon (i.e. the blood stained knife) and not take in the details (i,e, the face of the man).
Yuille and Cutshall (1986):
A Natural Experiment
Aim: To see if increased anxiety in a real-life shooting incident would affect witness's memory recall.
Method: In Canada, they interviewed 13 witnesses to a real life shooting incident involving the owner of a store and an unarmed thief. The storeowner was wounded but recovered and the thief was shot dead.
Results: Despite the anxiety which the experience had caused, the witnesses' accuracy of recall did not seem to be significantly affected. The witnesses appeared to be resistant to leading questions, they stuck to their original impressions of the event and their was little evidence of memory reconstruction. Those who were most distressed were most accurate after 5 months.
Conclusion: High anxiety did not seem to impair memory recall but actually enhanced the accuracy of EWT.
Aim: To compare the accuracy of information about a witnessed event recalled by young adults and the 'elderly' after a brief delay.
Method: Volunteers from several age groups talked to a female member of a research team for a few minutes. An hour later , the participants were asked to identify the woman in an identity parade.
Results: When the woman actually was in the parade, people aged over 60 identified her 48% of the time, compared with 47% in people aged between 20 and 60. This suggests no differences between the old and the young. HOWEVER, the research also found that when the woman wasn't in the identity parade, 90% of the over 60s thought they had correctly identified her, compared with 53% of the 20-60s making the same mistake.
Conclusion: The findings suggest that there is no difference between the older and the younger people in terms of recall. However, the fact that the elderly people were more likely to pick a person even when the target wasn't present in suggests that identification evidence from elderly people needs strong corroboration if a case is to be tried fairly.
Poole and Lindsay (2001):
Aim: Their aim was to see if children are susceptible to absorbing post-event information into their original memory.
Method: The method included engaging children aged 3 to 8 by watching a video of a science demonstration. That evening, the parents of the children read them a story, which contained some of the elements of the science demonstration but also included new information. The children were then questioned the next day at the science demonstration.
Results: The results were that they had incorporated much of the new information (from the parent's story) into their original memory. In another phase of the experiment, the children were asked to think very carefully about where they had got their information from (this is called source monitoring) and some of the older children then revised their account of the science demonstration and extracted the post-event information. However, the younger children did not seem to be able to do this.
Conclusion: This study has important implications for measuring the accuracy of small children's testimony since they seem very poor at source monitoring.