Factors affecting the accuracy of EWT

• Eyewitness testimony

  (EWT) refers to an account given by

  people when they have observed an event take place. For example, an individual who saw a robbery take place may be required to give a description to police officers and/or at a court trial. This will include describing details of the crime and the offender. Juries tend to pay close attention to eyewitness testimony and generally consider it a reliable source of information. However, research into this area has found that many factors can affect the accuracy of eyewitness testimony.
• Misleading information

  information given to someone that may change the way they remember an event. Misleading information can take two forms including leading questions and post-event discussion.
• What are the two types of Misleading information

  • Leading questions
  • Post-event discussion
• Loftus & Palmer (1974) aims and procedure

  Aims: To investigate the effect of leading questions on EWT.

  Procedure: 45 student participants were shown short video clips

  of cars colliding. They were split into 5 groups. All of the participants were asked: ‘About how fast were the cars going when they ________ each other’. Each group was given a different verb to fill in the blank. These verbs were ‘smashed, collided, bumped, hit or contacted’.
• Loftus & Palmer (1974) findings and conclusions

  Findings: When the verb ‘smashed’ was used, participants estimated that the cars were travelling much faster (on average 40.8mph) than when the verb ‘contacted’ was used (on average 31.8mph).

  Conclusion: The verb used in the question influenced the participants’ estimates of speed. This illustrates the effect of leading questions on the accuracy of EWT as the verb ‘smashed’ would infer the cars were traveling at a faster speed than the verb ‘contacted’.
• What is a criticism of Loftus & palmers investigation?

  researchers have criticised that the verb used in the question

  did not actually alter the participants’ memories of the event. Rather,

  they weren’t sure of the speed of the cars so just relied upon the verb

  to produce an estimate. In response to this, Loftus and Palmer

  conducted a further study to investigate whether the verb used in a leading question could actually alter the participants memeories.
• Loftus & Palmer (1974) 2nd research aims and procedure


  Aims: To investigate the effects of leading questions on EWT.

  Procedure: 150 student participants viewed a video of a car crash before being asked ‘how fast were the cars going when they _______ into each other. 50 were asked the key question with the word ‘smashed’, 50 with the word ‘hit’ and a control group of 50 weren’t asked any question. One week later they were questioned about their memory of the event, with the key question being ‘Did you see any broken glass?’ (there wasn’t any).
• Loftus & Palmer (1974) 2nd findings and conclusions

  Findings: Participants who originally heard ‘smashed’ were more likely to report seeing broken glass than those who had heard ‘hit’ and those in the control group.

  
  

  Conclusions: The verb ‘smashed’ would indicate that the cars were travelling at a faster speed and so would be more likely to result in smashed glass. The change in the verb therefore altered participants’ memory of the incident.
• What does Loftus & palmers research suggest

  Together, these studies suggest that leading questions do not just influence how participants decide to answer, but actually change their memories of events.Together, these studies suggest that leading questions do not just influence how participants decide to answer, but actually change their memories of events.
• What are the aims of Gabbert al (2003)

  To investigate the impact of post-event discussion on EWT.
• What are the Procedures of Gabbert al (2003)

  Participants watched a video of a girl stealingmoney from a wallet. The participants were either tested individually (control group) or in pairs (co-witness group). The participants in the co-witness group were told that

  they had watched the same video, however they had in fact seen different perspectives of the same crime and only one person had actually witnessed the girl stealing.

  Participants in the co-witness group discussed the crime

  together. All of the participants then completed a

  questionnaire, testing their memory of the event.
• What are the findings and conclusions of Gabbert al (2003)


  Findings: 71% of the witnesses in the co-witness group recalled information they had not actually seen and 60% said that the girl was guilty, despite the fact they may not have seen her commit a crime.

  Conclusions: Post-event discussion can impact the accuracy of eyewitness testimony.
• Evaluation of research into misleading information as a factor influencing the accuracy of EWT


  • it has resulted in important practical applications
  • much of the research has involved artificial tasks
  • on the accuracy of EWT is that it is typically conducted in artificial environments.
  • is that leading questions and post-event discussion are typically found to only affect unimportant aspects of memory.
• Anxiety as a factor affecting the accuracy of EWT

  Anxiety is defined as an emotion characterised by feelings of tension, worried thoughts and physical changes like increased blood pressure. Anxiety has been shown to have both a negative and positive impact on the accuracy of EWT.
• what are the negative effects of the accuracy of EWT

  Laboratory-based research has found that when participants experience high levels of anxiety, their eyewitness testimony is less accurate.
• what are the positive effects of the accuracy of EWT


  Research into real-life eyewitness testimonies has found that when witnesses have experienced high levels of anxiety, their eyewitness testimony is more accurate.