Improving the accuracy of eyewitness testimony (EWT)
One strategy for improving EWT is the cognitive interview (CI). Replacing the standard police interview (SPI), which depended on free recall of events, it is an interview procedure facilitating accurate, detailed recall, based on Tulving’s (1974) idea that several retrieval paths to memory exist. The CI also makes use of Tulving & Thomson’s encoding specificity theory (1973), which suggests the use of as many retrieval cues as possible to improve recall. The CI has 4 components:
1 change of narrative order — events being recalled in different chronological orders, e.g. from end to beginning
2 change of perspective — events being recalled from different perspectives, e.g. from the offender’s point of view
3 mental reinstatement of context — making use of environmental context, e.g. weather and emotional context (feelings) of the crime scene
4 report everything — all information is recalled, even trivial or muddled content.
Fisher et al. (1987) produced the enhanced cognitive interview (ECI) to overcome problems caused by inappropriate sequencing of questions. Extra features include: (a) minimisation of distraction, (b) reduction of anxiety, (c) getting witnesses to speak slowly, (d) asking open-ended questions. The modified cognitive interview (MCI) is a shortened version of the CI technique, which is often preferred by police forces as it takes less operational time. MCIs usually omit the ’change narrative order’ and ’change perspective’ components.
Fig 2.6 The modified cognitive interview is often used to allow police officers to interview children
Meissner & Fraser (2010) performed a meta-analysis of studies of the CI, including the ECI and the MCI, to assess their relative effectiveness. They reviewed 57 studies involving comparison of the CI with a control technique, such as the SPI, that had been published in peer reviewed journals. 32 per cent of the studies used the CI, 23 per cent the ECI and 45 per cent the MCI. The CI was found to produce more accurate detail than non-CI techniques, though there was a small increase in inaccurate details with the CI. The MCI produced more inaccurate details than the CI or the ECI and also produced slightly more false memories. This suggests that CIs are superior, as they produce more accurate, detailed information than non-CI techniques. The CI technique is therefore an effective means of conducting interviews, though some inaccurate detail is noticeable.
• Verkampt & Ginet (2010) interviewed children after a painting session, and found that the CI and 4 types of MCI were superior to the SPI in producing accurate detail and that versions of the MCI that removed the ’change of narrative’ component were most superior. This suggests that specific versions of the MCI are most appropriate for certain types of witnesses.
• Holliday (2003) gave children either a SPI or a MCI, specially designed for children, after showing them a video of a child’s birthday party. She found that the MCI produced more accurate detail than the SPI, demonstrating the effectiveness of MCIs with children.
• Milne & Bull (2002) found the ’report everything’ and ’context reinstatement’ components of the CI to be the key techniques in gaining accurate, detailed recall, which implies that some components of the CI are more effective than others.
The CI has potential uses within other organisations, not just the police, where accurate memory is necessary — for example, in the army, where debriefing of soldiers after active combat incidents is used to gain valid recollections.
Fisher & Geiselman (1988) have continued to develop the CI using information gained from watching ’good’ and ’poor’ interviewers. This has led to more open-ended questions and fitting the order of questioning to the witness’s order of experience, increasing accuracy of recall from 40 per cent to 60 per cent.
Variations of the CI have proven to be effective with specific groups of people in generating accurate witness recall of incidents.
Many police forces have problems using the CI, as it is too time-consuming for practical use. This has led to poorer or rushed versions of the technique being used, which can be less effective. The production of confabulations (false memories) is also problematic for police usage.
A limitation of CIs is that they are not generally effective as a method of memory enhancement for recognition of suspects from identity parades or photographs.
Police forces use widely differing versions of the SPI, making objective comparisons difficult to achieve.
MCIs can be used with children. Omitting the ’change perspective’ component is useful here, as children are often too young to see things from others’ point of view. Other groups of witnesses, like those with learning difficulties, can also be interviewed effectively with specifically designed forms of the MCI.