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Eyewitness Testimony

   Memory in real life!
Loftus (1974)
• Presented Pp’s with a fictitious
  case and asked them to judge the
  guilt of a man accused of robbing a
  grocers and killing the owner and
  his 5-yr. old granddaughter.

• On the evidence presented, 9/50
  said the man was guilty
What if there was an eye-witness?

• Other Pp’s were presented with the
  same case but were told that one of the
  shop assistants had testified as an
  eye-witness who was sure that the
  accused was the man who had
  committed the crimes.

• On this evidence, 36/50 judged the
  accused to be guilty
How reliable is the EWT?
• A third group of Pp’s were presented
  with the original evidence and the
  assistant’s EWT. However, they were
  also told that the defence lawyer had
  discredited the assistant. He is short-
  sighted and had not been wearing his
  glasses when the crime occurred so
  couldn’t possibly have seen the
  accused’s face.
How many students in the third
 group do you think judged the
     accused to be guilty?


   Explain your answer and say
   what this tells us about the
      importance of EWT.
The Results?
• In fact, 34/50 thought he was guilty!

• So, a mistaken witness who couldn’t
  possibly have seen the crime does seem
  to be better than no witness.
Eyewitness
testimony
Loftus & the role of misleading
                information
 Elizabeth Loftus (1975) suggested:
                                     Eyewitnesses are
        Memory is                 unreliable because the
      reconstructive             memory of an event can
                                 be affected by the type of
                                     questioning used
        Post-event effect
New information suggested after
an event can be encoded into the
                                     Leading questions
 original memory, resulting in the
  memory becoming inaccurate
Misleading Information
 Loftus & Palmer              AIM: to investigate the effects of
                            leading questions on the accuracy of
      (1975)                  an eye-witnesses immediate recall

PROCEDURE:                                              Which verb do
Laboratory Experiment                                     you think
                                                         elicited the
45 students / 5 groups (her own students)
                                                            highest
Students shown 7 films of different traffic accidents estimated speed?
P’s were given a questionnaire after each
Questionnaire’s included one critical question –
“How fast were the cars going when they hit each other?       Why?

One group (control group) were given ‘hit’ the other 4 were given
different verbs: Smashed, Collided, Bumped or Contacted
Misleading Information
                                               FINDINGS:
                 VERB                          SPEED (mph)
                 Smashed                              40.8
                 Collided                             39.3
                 Bumped                               38.1
                 Hit                                  34.0
                 Contacted                            31.8
CONCLUSION:
The form of questioning can have a significant effect on a witnesses
answer.
Leading questions provide post event information which can be
stored and affect the original memory forever, reducing the
accuracy of EWT
Misleading Information – A02

Think research
                              Who were the
  methods!                    participants?
 Where was
the research                   What’s
   done?           What’s     wrong with
                 good about      this?
   What’s not       this?
    so good
   about this?

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Eyewitness testimony

  • 1. Eyewitness Testimony Memory in real life!
  • 2. Loftus (1974) • Presented Pp’s with a fictitious case and asked them to judge the guilt of a man accused of robbing a grocers and killing the owner and his 5-yr. old granddaughter. • On the evidence presented, 9/50 said the man was guilty
  • 3. What if there was an eye-witness? • Other Pp’s were presented with the same case but were told that one of the shop assistants had testified as an eye-witness who was sure that the accused was the man who had committed the crimes. • On this evidence, 36/50 judged the accused to be guilty
  • 4. How reliable is the EWT? • A third group of Pp’s were presented with the original evidence and the assistant’s EWT. However, they were also told that the defence lawyer had discredited the assistant. He is short- sighted and had not been wearing his glasses when the crime occurred so couldn’t possibly have seen the accused’s face.
  • 5. How many students in the third group do you think judged the accused to be guilty? Explain your answer and say what this tells us about the importance of EWT.
  • 6. The Results? • In fact, 34/50 thought he was guilty! • So, a mistaken witness who couldn’t possibly have seen the crime does seem to be better than no witness.
  • 8. Loftus & the role of misleading information Elizabeth Loftus (1975) suggested: Eyewitnesses are Memory is unreliable because the reconstructive memory of an event can be affected by the type of questioning used Post-event effect New information suggested after an event can be encoded into the Leading questions original memory, resulting in the memory becoming inaccurate
  • 9. Misleading Information Loftus & Palmer AIM: to investigate the effects of leading questions on the accuracy of (1975) an eye-witnesses immediate recall PROCEDURE: Which verb do Laboratory Experiment you think elicited the 45 students / 5 groups (her own students) highest Students shown 7 films of different traffic accidents estimated speed? P’s were given a questionnaire after each Questionnaire’s included one critical question – “How fast were the cars going when they hit each other? Why? One group (control group) were given ‘hit’ the other 4 were given different verbs: Smashed, Collided, Bumped or Contacted
  • 10. Misleading Information FINDINGS: VERB SPEED (mph) Smashed 40.8 Collided 39.3 Bumped 38.1 Hit 34.0 Contacted 31.8 CONCLUSION: The form of questioning can have a significant effect on a witnesses answer. Leading questions provide post event information which can be stored and affect the original memory forever, reducing the accuracy of EWT
  • 11. Misleading Information – A02 Think research Who were the methods! participants? Where was the research What’s done? What’s wrong with good about this? What’s not this? so good about this?