1. How Can Evidence Be Made More Reliable?
Eye Witness Testimony
How Can Evidence Be Made More Reliable?

2. How Can Evidence Be Made More Reliable?
Many innocent people have been put in prison on the basis of eyewitness testimony.

3. How Can Evidence Be Made More Reliable?
Questions asked during a police interview may distort an eyewitness’s memory and thus reduce its reliability
Karen Matthews (Shannon’s mum) was arrested for abducting her own daughter.
Although we know that Karen wasn’t the witness  see this clip to see the techniques used to elicit information from Karen
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4. Fisher (1987) found….
witnesses were frequently bombarded with a series of brief, direct and close-ended questions aimed to elicit facts – they studied real life interviews by detective officers in Florida over 4 month period.
However, the sequencing of these questions often seemed to be out of sync with the witnesses’ own mental representation of the event.
Witnesses were often interrupted and not allowed to talk freely about their experiences.
As they were frequently interrupted….
….this made it hard for the witness to concentrate fully on the process of retrieval and thus reduced recall

5. How Can Evidence Be Made More Reliable?
The Home office has now issued clear guidance based on psychological research on police interviews
Interviews should move from free recall to general open-ended questions, concluding with more specific questions.

6. How Can Evidence Be Made More Reliable?
Geiselman (1985) argues that interviews should take into account the following features of human memory:
Memory traces are complex containing different kinds of information.
The effectiveness of a retrieval cue depends on the extent that the information it contains overlaps with information stored in the memory trace
Various retrieval cues may permit access to any given memory trace. Re-enactments of crimes are a means of providing cues to retrieve memories.

7. Cognitive Interviews (Geiselman et al 1985) Report EVERYTHING
1. The eyewitness then simply reports everything they can think of relating to the incident, even if the information is fragmented.

8. Reinstate the Context
2. the eyewitness tries to recreate mentally the context that existed at the time of the crime including the environment and their state of mind/mood.

9. Recall in reverse order
3. Report the episode in several different temporal orders moving backwards and forwards in time

10. Different Perspectives
4. The eyewitness is encouraged to report the details in various orders and from different perspectives

11. Remember….
These techniques all designed to enhance retrieval of the original memory
Although this kind of detail might seem trivial and poorly related to the actual witnessed event, it is designed to provide extra cues that might help to jog witnesses’ memory for more central details

12. Research has shown….
With the cognitive interview the average number of correct statements produced by eyewitnesses was 41.1
With the standard police interview the correct response rate was 29.4
– watching this again, could the interviewer have gone about the questions differently?

13. Tasks – see hand out
Why would you advise police officers to use the Cognitive Interview technique?
(Identify strengths and weaknesses)
Original Fisher, Geiselman articles on the Blog
Complete task sheet