Eyewitness testimony: Misleading information

• Loftus and Palmer arranged for 45 participants to watch clips of car accidents and then asked them questions about the accident. In the critical question participants were asked to describe how fast the cars were travelling. There were five groups and each group was given a different verb: hit, contacted, bumped, collided or smashed.
• Loftus and Palmer found that the verb 'contacted' resulted in a mean estimated speed of 31.8mph. For the verb 'smashed', the mean was 40.5mph. The leading question biased the eyewitness' recall of events.
• The response-bias explanation suggests that the wording of the question has no real effect on the participants' memories, but just influences how they decide to answer.
• Loftus and Palmer conducted a second experiment that supported the substitution explanation, which proposes the wording of a leading question changes the participant's memory. This was shown because participants who heard 'smashed' were later more likely to report seeing broken glass than those who heard 'hit'. The critical verb altered their memory of the incident.
• Gabbert et al. studied participants in pairs. Each participant watched a video of the same crime but from different points of view. This means each participants could see elements in the event that the other could not. Both participants discussed what they had seen before individually completing a test of recall.
• Gabbert found that 71% of the participants mistakenly recalled aspects of the event that they did not see in the video but had picked up in the discussion. In a control group where there was no discussion, 0% mistakenly recalled aspects they had not seen. This was evidence of memory conformity.
• Why does post-event discussion affect EWT?


  memory contamination or memory conformity
• Memory contamination = when co-witnesses to a crime discuss it, their eyewitness testimonies may become altered or distorted. This is because they combine misinformation from other witnesses with their own memories.
• Memory conformity = Gabbert concluded witnesses often go along with each other, either to win social approval or because they believe the other witnesses are right and they are wrong. Unlike memory contamination, the actual memory is unchanged.
• Research into misleading information has important practical uses in the criminal justice system. The consequences of inaccurate EWT can be very serious. Loftus believes leading questions can have such a distorting effect on memory that police officers need to be careful how they phrase their questions. Psychologists are sometimes asked to act as expert witnesses in court trials ad explain the limits of EWT to juries. This shows psychologists can help improve the way the legal system works, especially by protecting innocent people from faulty convictions based on unreliable EWT.
• However, Loftus and Palmer's participants watched film clips in a lab, a very different experience from witnessing a real event. Foster pointed out that what eyewitnesses remember has important consequences in the real world, but participants' responses in research do not matter in the same way (participants are less motivated to be accurate). This suggests researchers such as Loftus are too pessimistic about the effects of misleading information- EWT may be kore dependable than many studies suggest.
• EWT is more accurate for some aspects of an event than for others. Sutherland and Hayne showed participants a video clip. When participants were later asked misleading questions, their recall was more accurate for central details than for peripheral ones. Presumably the participants' attention was focused on central features of the event and these memories were relatively resistant to misleading information. This suggests original memories for central details were not distorted, an outcome that is not predicted by the substation explanation.
• A limitation of memory conformity is evidence that post-event discussion actually alters EWT. Skagerberg and Wright showed their participants film clips. There were two versions. Participants discussed the clips in pairs, each having seen different versions. They often didn't report what they had seen or what they had heard from the co-witness but a blend of the two. This suggest the memory itself is distorted through contamination by misleading post-event discussion, rather than the result of memory conformity.