Is Eyewitness Testimony reliable? Evaluate research that has investigated the effect of leading questions on memory.
An eyewitness testimony refers to an explanation someone gives of an event that they have witnessed, for example they may be required to give a description of a robbery or a road accident that they witnessed. This includes identification of perpetrators, details of the crime scene, etc. Eyewitness testimonies allow jurors to feel and see a clear picture of a crime that has been committed. The validity of eyewitness testimonies are often overestimated because of extra factors which may compromise the witness' accuracy. There are many factors that may compromise the accuracy of an eyewitness, for example anxiety or stress, reconstructive memory, weapon focus and leading questions.
Numerous psychological studies have shown that people are not very good at identifying people they saw only once for a relatively short period of time, the studies reveal error rates of as high as 50%. Many innocent people have been put in prison on the basis of eyewitness testimony, often questions asked during a police interview may distort an eyewitness' memory and therefore reduce its reliability.
Eyewitness identification is one of the most effective tools available to police and prosecutors, however under interrogation eyewitness' were frequently interrupted, this made it hard for the witness to concentrate fully on the process of retrieval and this reduced recall. Gary Wells (1998) researched 40 special cases and found that in all 40 cases the use of DNA proved that all 40 of the convicted suspects were innocent. In addition, in 36 of these cases, eyewitnesses wrongfully accused the suspect.
Leading questions introduce new information, and this new information may activate wrong schemas in the witness' mind; as a result the witness may recall events incorrectly. Eyewitness testimony are most affected by leading questions when witness' believes the other person knows more than them or when the witness' do not realise that they are being misled. (Eysenck, M.W. 2005).
The link between reconstructive memory and eyewitness testimony was made by Elizabeth Loftus in the 1970s. Loftus suggested that any new information about the crime that the witness took in had the potential to distort their recall of events. One of the most problematic sources of new information distorting original memories is leading questions that may be asked by police or lawyers. A leading question is a question that contains information previously unknown to the witness.
Loftus and Palmer (1974) asked participants to estimate the speed of cars in miles asking different forms of questions for different groups of participants. 45 American students were shown slides of a car accident and were asked to describe what they saw. Participants were asked specific questions, including “About how fast were the cars going when they hit each other?”. However, not all participants were asked this question with the word “hit”, which was substituted with “smashed”, “collided”, “bumped” and “contacted” for different groups of participants.
Loftus and Palmer found that the estimated speed was affected by the verb used. Participants who were asked the “smashed” question thought the cars were going faster than those who were asked the “hit” question. When participants were asked a week later if they saw any broken glass at the scene, although there was not any, participants in the smashed group were more likely to say yes. (Baddeley, A.D. 1999).
This research suggests that memory is easily distorted by questioning technique and information acquired after the event can merge with original memory causing inaccurate recall or reconstructive memory.
However, this study lacks ecological validity because the slides shown does not hold the same emotional impact as the witness of a real-life accident. This study suggests that the wording of questions can affect the judgements of an eyewitness, and therefore may prompt false memories. This study may not have very good ecological validity because student were used, therefore the findings cannot be generalised to the whole population. Artificial stimuli in the form of slides were used, this is not a realistic event or setting and may result in inaccurate answers.
There are also demand characteristics, where the participants gave higher speeds because they thought this is what the experimenter wanted rather than as a result of a leading question. Participants may have guessed the experimental hypothesis and acted accordingly. As a result, the internal and external validity of the research must be questioned and caution must be taken in generalising these findings to real-life eyewitness testimonies. Therefore, the extent to which psychological research can improve the reliability of eyewitness testimonies is limited because of the methodological weaknesses of the research.
In another study by Loftus and Zanni (1975) 100 students viewed part of a short film depicting a multiple car accident. Immediately afterward participants filled out a 22-item questionnaire which contained 6 critical questions. 3 of these asked about items that had appeared in the film, whereas the other 3 asked about items not present in the film. For 50 of the students, all the critical questions began with the words, “Did you see a..” and for the remaining 50 students the critical questions began with the words, “Did you see the..”. The word “the” that was used in the questions for half the participants indicates that the object being referred to exists. For example, “Did you see the broken headlight?”, in contrast to questions with the word “a”, which do not necessarily imply that the objects exists.
The results showed that witnesses who were asked questions with the word “the” were more likely to report having seen something, whether or not it had really appeared in the film, compared to those who answered questions with the word “a”. These results strongly suggest that even with this subtle changing in wording witnesses can be influenced and misled.
Whilst Loftus and Palmer (1974), and Loftus and Zanni (1975) have demonstrated the effect of leading questions and post-event information, this research was carried out in the artificial conditions of a laboratory.
An additional study of Loftus' used 150 university students, who watched a short video depicting an accident of a white sports car; participants were then asked 10 questions about what they had just seen. Half of the participants were asked “How fast was the white sports car going when it passed the barn while travelling across the country road?”. The other half of the participants were asked “How fast was the white sports car going while travelling across the country road?”. A week later the participants returned and answered 10 new questions about the accident, the question addressing the issue of the study was “Did you see a barn?”. 13 (17.3%) participants who were in group 1 and only 2 (2.7%) participants who were in group 2 answered yes. (Loftus, E.F. 1975).
In a study by Loftus et al (1978) participants watched a slide sequence in which a car is driving down the road, it turns right and hit's a pedestrian. Half of the participants are shown a “yield” sign in their slide sequence, whilst the other half are shown a “stop” sign. Some of the participants were then asked a question containing a misleading suggestion about the sign that they had seen. The misleading suggestion was the question asking them about the sign that was not really shown to them. The results showed that many of the misled participants claimed to have seen the sign that was suggested in the question they answered and not the one they had actually seen. These studies demonstrate that misleading post-event information affects what people incorrectly report about the past. (Pohl, R. 2004).
In contrast to the results found and theories proposed by Loftus, researchers Yuille and Cutshall (1986) interviewed witness' of a real crime in which a thief attempted to rob a shop owner who he shot, the owner returned fire and the thief was shot dead. The police interviewed witnesses who were at the scene of the crime; 5 months later they were re-interviewed. The results showed that the witness' recall was found to be accurate even after this 5 month period of time. In addition to this, 2 misleading questions were placed in by the research team to manipulate the memory of the witnesses, however these misleading questions had absolutely no effect on any of the witnesses as they were not misled to believe something else had happened. The Yuille and Cutshall study illustrates that misleading questions do not always have the same effect as has been found in laboratory studies such as the Loftus and Palmer study.
Loftus' findings seem to indicate that memory for an event that has been witnessed is highly flexible. If someone is exposed to new information during the interval between witnessing the event and recalling it, this new information may have marked effects on what they recall. The studies show that most of the participants were completely unaware that they had been misled, which helps reduce the risk that the results produced in Loftus' studies were simply the result of demand characteristics.
Research on eyewitness testimony has had a positive impact on police procedures, for example the cognitive interview has been developed based on Loftus' findings on leading questions and post-event information. Geiselman found that the average number of correct statements produced by eyewitnesses in a cognitive interview was 41.1 compared to only 29.4 in a standard police interview. Research suggests the cognitive interview yields twice as many correct statements as the standard police interview and so this has improved the reliability of eyewitness testimony. (Eysenck, M.W. 2005).
Clifford, B.R. and Scott, J. (1978). Individual and situational factors in eyewitness testimony. Journal of Applied Psychology. 63 (3), 352-359.
Loftus, E.F. (1975). Leading questions and the Eyewitness Report. Cognitive Psychology. Vol. 7, 560-572.
Eysenck, M.W. (2005). Psychology for AS Level. 75-85. Taylor and Francis.
Baddeley, A.D. (1999). Essentials of Human Memory. 204-217.
Pohl, R. (2004). Cognitive Illusions: A Handbook on Fallacies and Biases in Thinking, Judgement and Memory. 345-349.
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