Eyewitness testimony and Post-event discussion

• what is an eyewitness testimony


  it is the evidence given in court or a police investigation by someone who can affect the accuracy of eye witness reports
• what are the factors that can affect the accuracy of eye witness reports 


  ->misleading information

  ->leading questions

  ->anxiety

  ->post event discussion
• case study-Leading Questions; Loftus & Palmer (1974)exp 1


  ->aim: to investigate the effect of leading questions on the accuracy of eye-witness testimony

  ->method: -the sample was 45 American students, who were divided into five groups of nine

  -in an independent measures design, all the participants watched a video of a car crash and were the asked a specific question about the speed of the cars

  -Loftus and Palmer manipulated the verb used in the question. e,g- 'How fast were the cars going when they smashed/collided/bumped/hit/contacted with each other?
• what were the finding/results and conclusions of the the Loftus and Palmer (experiment1) case study?


  ->they found that the estimated speed was affected by the verb used. E.g participants who were given the verb 'smashed' reported an average seed of 40.5mph

  ->whereas, participants who were given the word 'contacted' reported an average speed of 31.8mph, an overall difference of 8.7mph

  ->conclusion: the results show clearly that the accuracy of eyewitness testimony is affected by leading questions and that a single word in a question can significantly affect the accuracy of our judgement
• Loftus & Palmer (1974)- experiment 2


  -> L&P used a different sample of 150 American students, who were divided into three evenly-sized groups

  ->all students watched a 1 minute vid depicting a car accident and were then given a questionnaire to complete

  ->1st group: "How fast were the cars going where they smashed into each other?"

  ->2nd group: "How fast were the cars going when they hit each other?"

  ->control group: nothing

  ->1 week later; the critical question was: "did you see any broken glass?"

  ->no broken glass in the video clip
• what was the aim of the Loftus and Palmer, experiment 2


  to investigate further how leading questions can affect eyewitness testimony
• what were the results of the Loftus & Palmer, experiment 2


  ->results: 32% of the participants who were previously questioned using the verb smashed reported seeing broken glass; 14% of the participants who were previously questioned using the verb 'hit' reported seeing broken glass and 12% of the control group reported seeing broken glass
• what were the conclusions of the Loftus & Palmer experiment 2?


  ->the participants who were questioned previously using the verb 'smashed' were significantly more likely to report seeing the broken glass as a result of the earlier leading question

  ->the verb 'smashed' has connotation of faster speeds and broken glass and this question led the participants to report seeing something that was not actually present

  ->their memory of the original event was distorted by the question used one week earlier, demonstrating the power of leading questions
• define the term post-event discussion

  when witness/ co-witnesses discuss the details of a crime or accident following an accident
• case-study on post-event discussion

  Gabbert et al, 2003
• what was the aim of the study by Gabbert et al, 2003

  to investigate the effect of post-event discussion on the accuracy of eyewitness testimony
• method- Gabbert et al, 2003

  ->sample: 60 students from the uni of Aberdeen + 60 older adults recruited from a local community

  ->participants watched a vid of a girl stealing money from a wallet
• how were the participants tested in the Gabbert et al 2003

  ->the participants were either tested individually (control group) or in pairs (co-witness group)

  ->they were told that they watched the same video -but they watch different perspectives of the same crime and only one person had actually witnessed the girl stealing

  ->all their participants then completed a questionnaire, testing the memory of the events
• what were the results of the Gabbert et al, 2003?

  ->71% of the witnesses in the co-witness group recalled the information they had not actually seen and 60% said that the girl was guilty

  ->despite the fact that they had not seen her commit a crime
• what was the conclusion of the case-study done by Gabbert et al, 2003

  ->these results highlight the issue of post-event discussion and the powerful effect this can have on the accuracy of eyewitness testimony
• describe the case study done by Braun et al, 2002-> can misleading info create false memories?

  ->this case study tested students who had all been to Disneyland

  ->Participants were asked to evaluate some advertising material about Disney & some of the participants were given material with misleading info
• what was the conclusion of the Braun et al, 2002?

  ->participants who had been exposed to the misleading info were more likely to report having shaken hands with Bugs bunny, even though that couldn't have happened
• what was the conclusion of the Braun et al, 2002?

  ->participants who had been exposed to the misleading info were more likely to report having shaken hands with Bugs bunny, even though that couldn't have happened