How can eyewitness testimony be improved?

Eyewitness testimony is often inaccurate, and individuals are often overly and inaccurately confident in their memory of a specific event. As EWT can be influenced by a number of factors, including anxiety and factors relating to the event, for example the presence of a weapon, methods have been taken to work to improve EWT. The Cognitive interview is a way of interviewing eyewitnesses to improve the accuracy and detail of their memory of a crime, based on what psychologists have found out about memory. Memories for events like crimes are made up of lots of different types of information stored in different parts of the human memory system. More accurate and detailed memories can be recalled if interviews help the witness to access and retrieve information from different parts of their memory system. The cognitive interview intends to do this by helping the witness reconstruct the original context of the crime and retrieve lots of different information about the crime stored in the memory. There are 4 main components to the cognitive interview:-    Report everything: include every single detail of the event, even if it is minor or not directly related to the crime. This is intended to improve the detail and accuracy of the memory of the crime.-    Mental reinstatement of the original context: mentally recreate the situation at the time of the crime. This is also intended to improve the detail and accuracy of the memory of the crime.-    Change the order: reverse the order of what happened. This helps to access more information about the crime -    Changing the perspective: recall the crime from many different points of view eg other witnesses, the person carrying out the crime, the victim. This allows the eyewitness to retrieve more information stored in memory. 
EvaluationKohnken et al conducted a meta analysis of 53 studies and found 34% increase in correct recall using the cognitive interview compared with standard interview techniques. This supports the cognitive interview as a better way to interview eye witnesses than standard interview techniques. Similarly Geiselman et al (1984) found that more correct items were found with the CI without an increase in the number of incorrect items.  Holiday (2003) showed two groups of children aged 4-5 and 9-10 years a 5 minute video of a child’s birthday party and the next day they were all interviewed about what they had seen. Those questioned using a cognitive interview had more correct details recalled. Therefore the CI is also effective with children. Stein and Memom tested female cleaning staff in Brazil and found cognitive interviews increased the amount of details remembered about a crime. The details remembered were often useful to police including important details such as a criminals description. This is supporting cognitive interview and has a more representative sample of participants. The evidence above therefore suggests that the cognitive interview is effective with ordinary people as well as students.WeaknessesThe cognitive interview contains several different components and so therefore takes a longer amount of time and needs more training for interviewers. Additionally it is unclear whether all of the 4 components are necessary for an effective interview. It is less effective at enhancing recall when used at longer intervals of time after the event. This is because often people will need cues in order to remember information, which is not given in a cognitive interview. Memon and Bull (1994) demonstrated the need for interviewer training. In this study experienced police detectives received only 4 hours of training into the use of the CI. This brief training did not produce any significant increases compared to the standard interview, in the amount of information a witness could remember.