factors affecting eye-witness testimony

• leading questions - misleading info study

  • by Loftus and Palmer
  • 45 students watched clips of car accidents and were asked after, how fast the cars were travelling when they "HIT"
  • 5 groups given different verbs in the critical question: contacted, hit, bumped, collided, smashed
• results of leading questions - misleading info study

  mean estimated speed answered for each group:

  • contacted = 31.8 mph
  • smashed = 40.5 mph

  This suggests the leading question biased the participants recall of an event.
• post event discussion - misleading info study

  • by Gabbert et al.
  • studied participants in pairs
  • each PP watched a video of the same crime but from different angles, so they could see elements the other couldn't.
  • both PPs then discussed what they had seen and individually take a recall test.
• results of post event discussion - misleading info study

  • 71 % of PPs mistakenly recalled aspects that they didn't see in the video but had picked up from discussion
  • control group with no discussion = 0 % made mistakes
  • This suggests evidence of memory conformity.
• anxiety has a negative affect on recall - anxiety study

  • by Johnson and Scott
  • PPs believed they were taking part in a different experiment and were seated in a waiting room
  • condition 1 (low anxiety): PPs heard a casual convo in the next room and saw a man walk past with a pen and grease on his hands.
  • condition 2 (high anxiety): PPs heard shouting and sound of breaking glass then saw a man walk past with a bloody knife
• results of anxiety has a negative affect on recall - anxiety study

  PPs later picked out the man from 50 photos

  • low anxiety = 49 % accurate
  • high anxiety = 33 % accurate
  • This suggests that the presence of the weapon created tunnel vision, causing the PPs to focus on the weapon rather than other details
• anxiety has a positive affect on recall - anxiety study

  • Yuille and Cutshaw studied a real shooting in a gun store in Canada where the owner shot the thief dead.
  • 21 witnesses but 13 took part in the study.
  • PPs were interviewed 5 months after the incident and compared the accuracy of detail in the report to the original police reports.
  • PPs were also asked about stress levels during event and if they had any emotional problems after
• results of anxiety has a positive affect on recall - anxiety study

  • PPs were very accurate on accounts and there was little change in accuracy after 5 months.
  • PPs who reported more stressed = more accurate
• evaluate leading questions study - misleading questions (STRENGTHS)

  • lab experiment = control of extraneous variables so reliable results due to standardised procedure (same video for all PPs)
• evaluate leading questions study - misleading questions (LIMITS)

  • lab experiment = lacks mundane realism as in real life you would be distressed.
  • demand characteristics = PPs know they're being studied so may pay more attention to video than in real life.
  • unreliable sample = young students so they may be less experienced with driving so are more affected by leading questions on car speed. So lacks population validity.
• evaluate post event discussion study - misleading questions (STRENGTHS)

  • lab experiment = high controls of extraneous variables so reliable and easy to replicate.
  • good population validity = younger and older sample
• evaluate post event discussion study - misleading questions (LIMITATIONS)

  demand characteristics = PPs know they're being studied so may pay more attention to the video than in real life
• evaluate negative anxiety study (STRENGTHS)

  • lab experiment = reliable and can be replicated because of standardised procedure
  • no demand characteristics because the PPs didn't know the true aim of the study = authentic reactions = valid results.
• evaluate negative anxiety study (LIMITS)

  ethical issues = aim of the study was to create distress. Therefore lacked protection from harm and full informed consent.
• evaluate positive anxiety study (STRENGTHS)

  • natural study = has ecological validity and no demand characteristics because the reactions were authentic
  • PPs given right to withdraw = only 13 / 21 witnesses took part
• evaluate positive anxiety study (LIMITS)

  • natural study = cannot control extraneous variables. e.g. some people may have been closer and therefore have better accuracy
  • cannot be replicated = unethical bc the study was natural
  • lack of protection from harm = causing PPs distress when asking to recall event.