factors affecting eyewitness testimony

• Misleading questions= a question that suggests to the witness there is a certain answer

  Post even discussion= when co witnesses discuss a crime and their testimonies become contaminated , memory us altered.
• Loftus and palmer

  Aim= See the effects of misleading questions (estimates of speed)

  Procedure= 45 pp watched a series of car accidents, then asked a critical Q: Describe how fast the car was travelling. Each group was asked a different verb such as smashed.

  findings= Contact had lowest mean estimate of speed (31mph) while smashed was the highest (40 mph)

  Conclusion= The leading question made the answer bias
• Loftus and palmer then wanted to see if the leading questions changed the pp memory of the event.

  Procedure= The pp answered another question a week later ( was there broken glass). Ones who had smashed as their verb said yes when there wasn't.

  It altered the pp memory of the clips, making it inaccurate.
• Gabbert et al investigated the effects of Post event discussion on the accuracy of EWT.

  Procedure= pp watched a video of a girl stealing money. They were then put into pairs (told they watched the same video) and asked to discuss the crime.

  Findings= 71% of the witnesses recalled information they had not seen. 60% said the girl was guilty even if they didn't see her commit a crime.

  PED has a powerful effect on the accuracy of EWT.
• One strength is that it has good practical applications to the criminal justice system. Evidence shows that leading questions can have a big effect on memory. This shows that police need to be careful when asking questions. This allowed the cognitive interview to be created to improve the accuracy of testimonies to improve the legal system
• A limitation is that the information used artificial materials in a lab study. This means it doesn't create any stress as there would be in a real life scenario. This suggests the research lacks ecological validity as the pp can demonstrate demand characteristics.
• Negative effect of anxiety on recall done by Johnson and Scott

  Procedure= pp were divided into 2 conditions ( low anxiety/high anxiety). They sat in a waiting room and those in the first condition heard an argument then a man walks out holding a pen with grease. In the other condition there was the sound of glass breaking accompanying the shouting. The man walks out holding a bloody knife. Pp then asked to recall the mans face from photos.

  Findings= 49% accuracy in low anxiety condition. 33% in high anxiety

  Conclusion = Focusing on the weapon instead of the mans face( tunnel effect).
• Positive effect of anxiety composed by Cutshall et al in a natural setting.

  Procedure= real life shooting in Canada . Witnesses interviewed by police, rated their anxiety on a scale of 1-7.

  5 months later they were asked to give an account and was compared to the original statement.

  Findings= 88% who remained accurate in recall also scored high in anxiety.

  conclusion= anxiety has a positive effect on ewt
• Yerkes-Dodson law= contradicts the findings of anxiety because it states there is an optimum point which is medium levels of anxiety. This leads to better recall at medium arousal/anxiety
• A limitation is that anxiety may not be related to weapon focus as the pp were more surprised than scared in Johnsons weapon focus study. EW accuracy poor in unusual conditions. Suggests that it is not telling us much about anxiety.
• Another limitation is that lab studies do not create anxiety levels from real life scenarios. Johnson et al study lacks ecological validity as the pp may have been anticipating something was going to happen. This shows that the weapon focus effect is false in the context of the crime.
• The research was highly unethical as it created distress to the pp. They were also decieved about the nature of the research. Those who know someone or were involved in a kife crime would have psychological harm regarding the bloody knife. Shows that real life studies are more beneficial
• Research has found individual differences can impact eyewitness recall for example, own age bias. Rhodes et al showed 24 individuals from three different age groups, a series of photos and asked to rate them for attractiveness. they were then shown the same photos mixed in with new ones and asked to recall. Found that people would have a better recall if they were in the same age group. Suggesting that own age bias can impact EW.