Research in to factors affecting EWT

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Loftus (1987)

A: Investigate how the anxiety produced by the presence of a weapon affects EWT accuracy

P: In an indepedent Measures Design study, participants either heard a discussion about an equipment failure, then a man emerged holding a pen with grease on his hands. In the second condition, participants heard a heated exchange, before a man emerged holding a knife with blood on it

F: Those in the first condition identified the man 49% of the time. Those in the second condition only identifies the man 33% of the time

Co: This suggest that the anxiety produced by the presence of a weapon leads to decreased accuracy of eye witness testimonies because the person will focus on the weapon, as opposed to the person's face

Cr: As this study was completed in a laboratory environment, the effects may differ to real life so it lacks in ecological validity. Psychological harm could have arisen as a result of seeing the weapon, so asking participants to recall details of it could be distressing.

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Loftus and Burns (1982)

A: Investigate how the anxiety produced by witnessing a violent crime affects EWT accuracy

P: In a laboratory experiment, participants were exposed to one of two condition. In the first, participants watched a non-violent film of a crime. In the second, participants watched a violnet film of a crime whereby a boy was shot in the face.

F: They found that those who saw the violent version were less accurate in recalling information about the crime

Co: This suggests that anxiety leads to decreased accuarcy of EWT

Cr: As this study was done in a laboratory settings, the study lacks ecological validity because it could differ to real life, because in reality someone may not be paying that much attention to the crime as they were not told to focus on the person or watch closely. Also, there are ethicla issues to consider. Psychological harm could have arisen due to watching violent videos, so asking them to recall details could be distressing.

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Yuille and Cutshall (1986)

A: Investigated the effects of anxiety on the accuracy of EWT in natural settings

P: They interviewed 13 witnesses to an armed robbery of a shop, wherby the theif was shot 6 times by the shopkeeper and died. Some witnesses had seen the incident close up, while others were more distant.

F: They found that the accuracy of EWT was very high, even 5 months after the event, and even after the witnesses had been subjected to misleading question. This was particulary true of those who were closest to the shooting, and presumably the most anxious.

Co: This suggests that high anxiety does not decrease accuracy of EWT, as suggested by lab studies, by actually increases it.

Cr: Due to participant variables, the people close to the shooting may not have neccessarily been the most anxious. For example, if there was a old lady at the back, she may have been the most terrified. Plus, the people closest may have not actually seen the most as they could have been simply looking the other way. Plus, the study is not scientific or replicable as variables were not tightly controlled.

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Christianson and Hubinette (1993)

A: Investigate the effects of anxiety on the accuarcy of EWT in real life settings.

P: They interviewed 110 eye-witnesses who had witnessed genuine bank robberies. The interviews were conducted up to 15 months after the event. Some of the witnesses had been onlookers who happened to be in the bank at the time, whereas others were bank employees who had been directly threatened in the robberies.

F: They found that the victims who were directly threatened in some way during the robbery were more accurate in their recall than those who were just bystanders. This accuaracy continued to be evident 15 months after the event.

Co: This suggests that high anxiety does not decrease accuracy of eye witness testimonies.

Cr: This study has good ecological validity, but is not scientific or replicable because variables were not tightly controlled. Plus, the results are on the assumption that the people directly threatened were the most anxious, whereas they may have remained calm or an old lady at the back of the bank could have been the most terrified about the situation.

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Parker and Carranza (1989)

A: To invstigate the effects of age on the accuracy of EWT to see if children could provide good testimonies.

P: They showed both primary school and college aged students a slide sequence of a mock crime and then asked them to identify a target person from a range of photographs; they were given the option of 'target not present'.

F: They found the younger participants were more likely to choose a photo of someone rather than selecting the 'target not present' option

Co: This suggests that child witnesses may be less accurate in identification and are also more likely to make false identifications

Cr: As it was a lab experiment, it could lack in ecological validity, so it may be difficult to apply the findings to real life situations.

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Roberts and Lamb

A: To investigate children's accuracy in EWT

P: They analysed 161 police interviews with children regarding allegations of abuse

F: In 68 of the interviews, the interviewer misinterpreted "in private" as "in the privates" and in 2/3 of these cases, this remained uncorrected by the children

Co: This suggests that people of a young age do not have accuarte EWT as they can be easily mislead

Cr: The study has good ecological validity, but is not scientific or replicable as the variables were not tightly controlled.

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Other studies into the accuracy of children's EWT

Poole and Lindsay (2001) - found that children included a lot of post event information in their recollections of a science demonstration, suggesting they are affected by this and thus provide more inaccurate EWT

Warren et al (2005) - found that older children were more influenced by leading questionsthan adults. This suggests children do not have have accurate EWT

Davies - found that differences between child and adult interviews were overstated and that children can provide very valuable EWT as long as care is taken during the interview procedure. This suggests young children can have accurate EWT

Anastasi and Rhodes (2006) - used particpants aged 18 - 78 years old and found evidence for own age bias - people doing better when asked to identify people of their own age

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Kapel et al (2001)

A: To investigate the effects of old age on the accuracy of EWT and recall

P: Elderly people watched a video of a bank robbery and were asked to recall details of what happened and the criminal

F: They found that the elderly were less accurate in their recall and they were more vulnerable to leading questions

Co: This suggests that the elderly provide less accurate or less detailed EWT

Cr: There could have been confounding variables that effected the results, for example older people may have poorer health, leading to an appearance in memory impairment

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Coxon and Valentine

A: To investigate the impact of age of an eye witness on the accuracy of EWT and recall

P: They asked children, young adults and the elderly questions containing misleading information after they had watched a video. They subsequently asked participants a further 20 specific questions to asses whether they had been influenced by the misleading information or not.

F: They found that the elderly were less suggestible to the misleading information and were the only age group not to show a significant misinformation effect

Co: This shows that people of an older age group do have and accurate recall and can provide accurate eyewitness testimonies.

Cr: As this research was lab based, it lacks in ecological validity,so it could be difficult to apply the findings to real life similar situations

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Cohen and Faulkner

A: To investigate the impact of age on EWT

P: They showed 70 year old and 35 year olds a film of a kidnapping and then presented them with misleading information before asking them to recall and explain what happened in the film

F: They found that the 70 year olds were more likely to be misled and include more incorrect information than the 35 year old participants

Co: This suggests that people of an older age do not have an accurate recall, meaning their eye witness testimonies are less accurate

Cr: This research was lab based, so the results lack ecological validity and may not be applicable to real life settings. Also there could have been confounding variables that effected the results, for example older people may have poorer health, leading to an appearance in memory impairment

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Memon et al (2003)

A: To investigate the effects of age on the accuracy of recall and eye witness testimonies and the the accuracy of EWT over time.

P: They showed a film to participants and then tested identification of the criminal a week later.

F: They found that older participants (aged 60-82) were significantly less accurate than the participants in their recall.

Co: This suggests elderly people can provide less accurate eye witness testimonies than younger people. It also shows that the accuracy of EWT diminishes over time.

Cr: There could have been confounding variables that effected the results, for example older people may have poorer health, which could lead to an appearance in memory impairment. Also, as the experiment was lab based, it lacks ecological validity meaning it may be difficult to apply it to real life.

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