Discuss research into one factor which affects eyewitness testimony

by vutantruong (student)

Steven Truong

Discuss research into one factor which affects EWT (12 marks)

Eyewitness testimony is the evidence given in court or in police investigations by someone who has witnessed a crime or an accident.

Misinformation is a factor which can affect eyewitness testimony. The exposure to misleading information after the encoding of the event causes distortion in memory recall, this occurs when information presented later interferes with the ability to retain previously encoded information and displacement happens where the old encoded information is replaced with the new misleading information. This questions the reliability of eyewitness testimony.

Loftus in 1975 did a study which aimed to discover the influence of misleading information on eye-witness testimony. 150 participants were shown a film then divided into 2 groups. Group 1 (the control group) were asked 10 questions which were consistent with the original film whereas Group 2 (the experimental group) were asked the same questions apart from 1 question which was ‘How fast was the white sports car going when it passed the barn?’. This was a misleading question as it suggested that there was a barn in the film, even though there wasn’t one (misinformation). A week later both groups were asked ‘did you see the barn?’ 17% of the experimental group reported seeing a barn in the original film but only 3% of the control group made this error.

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For those in the experimental group, it is likely that they formed an image of a barn, which over time became implanted into their mental representation of what they had actually seen in the film. This study shows that misleading information can alter the mental representation a witness has of an event, consequentially reducing their accuracy. However this study could be criticised as it was a lab experiment so it was an artificial task as it used a realistic video footage so the participants knew they had to pay attention. It lacks ecological validity due to the use of a video footage and not a real life scenario. It also involves demand characteristics so it could be argued there was no real change to the memory, and that participants were simply altering what they say. The use of the footage cause distress as it was of a car accident and the leading question is example of deception thus a debriefing is crucial.

In 1978 Loftus et al. did another study to demonstrate the effects of misleading questions on accuracy of event recall, unlike the previous study they showed a set of photo slides showing the events leading up to a car accident. Group 1 saw a red car stopping at a junction with a ‘Yield’ sign where as group 2 saw the same one except it was a ‘Stop’ Sign. A questionnaire was given to the participants are viewing the slides. Half the participants in each group were asked a question about whether they saw another car pass by, when the red car was stopped at the ‘Stop’ sign whereas the other half were asked if it was stopped at the ‘Yield’ sign. This meant that half the participants in each group were asked a misleading question and the other half of each group were asked a question that was not misleading, as it was consistent with what they had seen. After 20 minutes they were all shown 15 pairs of random slides and had to select one slide from each pair, what they had seen earlier. There was a critical pair of slides, where one slide showed the red car stopped at ‘Yield’ sign, the other, a ‘Stop’ sign. Only 41% of the participants that were provided with the misleading question selected the correct slide, compared to 75% of those who had received the non-misleading question.

Loftus suggested that the misleading question replaced the true information from memory and that the original memory was no longer stored and only the misleading information could be accessed however, participants were only shown photo slides which are not representative of real-life conditions therefore lacks ecological validity.

Bekerian and Bowers (1983) study suggests that it is possible that the original information is only ‘covered’ by the misleading information so it may still be uncovered to be retrieved again. They replicated the study by Loftus et al (1978) where the car is showed stopping at a Stop and Yield sign. The Loftus study involved the participants being shown the slides in random order whereas the slides were presented in chronological order in Bekerian and Bowers study. It was found in this study that the memory of the participants who were provided with the misleading information was nearly as accurate as that of those provided with the consistent non-misleading information. Bekerian and Bowers concluded that the original memory wasn’t lost for the participants and that the display of the slides in the correct order provided sufficient cues for the original memory to be retrieved, despite the misinformation provided. This opposes Loftus’ conclusion that the information is displaced, where instead the information is just covered but can still be uncovered again. However there has been criticism towards this study as McCloskey and Zaragoza (1985) could not replicate the findings therefore shows that it lacks reliability.

Loftus’ two studies provides sufficient evidence as well as the Bekerian and Bowers’ study that misinformation does indeed have an effect on eyewitness testimony however one study (Bekerian and Bowers) argues that misinformation does not displace the encoded memory however its results has not be able to be replicated therefore Loftus initial conclusion that misinformation can alter a person’s mental representation of an event still stands although its ecological validity may question if it can be applied to eyewitness testimonies or not.