EWT: misleading information

• Misleading information - incorrect information given to the eyewitness (usually after the event). It can take many forms such as leading questions or post event discussion
• Leading question - a question which because of the way it is phrased, suggests a certain answer
• Loftus and Palmer divided 45 university students into 5 groups and showed them a video of a car crash in a lab study. When they asked the pps questions afterwards about the car crash, they changed the verb in their question about the pps estimate for the vehicle’s speed. They found the verb ‘smashed’ had the highest speed estimate of 40.5mph whereas ‘contacted’ had the lowest speed estimate of 31.8mph
• Response bias explanation - wording of question has no real effect on memory but influences how they decide to answer
• Substitution explanation - wording of the question actually changes the pps memory
• The criminal justice system relies heavily on the accounts of eyewitnesses and Loftus and Palmer’s research highlights the danger of misleading information being used in the courtroom by lawyers, as a single misleading question can affect the accuracy of EWT
• Post-event discussion - occurs when there is more than one witness to an event. Witnesses may discuss what they have seen with co-witnesses or other people. This may influence the accuracy of each witness’ recall of the event.
• Gabbert (2003)

  • 60 students from aberdeen university and 60 older adults from local community
  • Some were tested individually as a control group
  • Split into pairs, with 2 conditions. One person watched a video of a woman in an office whilst the other saw a video which clearly showed her stealing. They were told they saw the same video. They then discussed the video together and then afterwards they individually took a test of recall. 

  71% mistakenly recalled aspects of the event they didn’t see. 60% who didn’t see her steal said she was guilty.
• Source monitoring theory - memories of the event are genuinely distorted. The eyewitness can recall information about the event (accurate and inaccurate) but they can’t recall where it came from
• Conformity theory - argues that eyewitness memories are not actually distorted by post event discussion. Instead the eyewitness’ recall appears to change only because they go along with the accounts of other people. Links to ISI and NSI
• Gabbert et al's results have questionable ecological validity. The pps in the co witness conditions witnessed different perspectives of the same crime, as would typically be the case in real life crimes. However they knew they were taking part in an experiment and were more likely to pay attention to the details in the video
• Gabbert's sample has 60 university students and also 60 older adults which means there is a range of ages and life experience
• Although providing an insight into the effect of post event discussion on eyewitness testimony, the research does not give an explanation for why this effect occurs