EWT : misleading information

• Loftus and Palmer - leading questions


  • Procedure - 45 participants watched clips of a car accident and then answered questions about the speed. The critical question was 'How fast were the cars going when they hit eachother ?. Five groups of participants where each given a different verb in the critical question : hit, contacted, bumped, collided and smashed.
  • Findings - the verb 'contacted' produced a mean estimate of 30mph whereas the verb ' smashed' produced a mean estimate of 40mph. The leading question biased eyewitness recall of an event.
• why leading questions affect EWT

  1. Response bias explanation - wording of a question has no enduring effect on an eyewitness's memory of an event, but influences the kind of answer given
  2. Substitution explanation - wording of questions does affect eyewitness memory, it interferes with the ordinal memory, distorting its accuracy.
• Gabbert - post event discussion


  • Procedure - Paired participants watched a video of the same crime, but filmed so each participant could see elements in the event that others couldn't. Both participants discussed what they had seen on the video before individually completing a test of recall.
  • Findings - 71% of participants wrongly recalled aspects of the event they did not see in the video but had heard in the discussion. This was evidence of memory conformity.
• Why does post event information affect EWT

  1. Memory contamination - when co witnesses discuss a crime, they mix information from other witnesses with their own memories.
  2. Memory conformity - witnesses go along with each other to win social approval or because they believe the other witnesses are right.
• Evaluation

  One strength is real world application in the criminal justice system. The consequences of accurate eyewitness testimony are serious. Loftus argues police officers should be careful in phrasing questions to witnesses because of distorting effects. Psychologists are sometimes expert witnesses in trials and explain limits of eyewitness testimony to juries. Therefore, psychologists can improve how the legal system works and protect the innocent from faulty convictions based on unreliable eyewitness testimony.
• Evaluation

  One limitation is demand characteristics. Lab studies give researchers high control over variables so they can demonstrate that misleading information causes inaccurate eyewitness testimony. But lab experiments suffer from demand characteristics as participants want to help so they guess when they can't answer a question which creates low internal validity. Therefore, to maximise internal validity researchers should reduce demand characteristics by removing the cues that participant use to work out the hypothesis.
• Evaluation

  One limitation is that evidence does not support memory conformity. Skagerberg and Wright's participants discussed film clips they had seen. The participants recalled a 'blend' of what they had seen and what they had heard from their co-witnesses, rather than one or the other. This suggests that the memory itself is distorted through contamination by post event discussion and is not the result of memory conformity