Evaluation of the Cognitive Interview

• strengths

  supporting research evidence (Kohnken et al, Milne and Bull)
• supporting research evidence

  an abundance of research has demonstrated the special benefits of the Cognitive Interview (CI)

  studies overall revealed how the use of the cognitive interview has improved the accuracy of eyewitness’ accounts compared to the standard police interview

  a meta-analysis was carried out by Kohnken et al. (1999). they found an average increase of 41% in the amount of correct information generated in the CI compared with standard interviewing techniques. in addition Milne and Bull (2002) found that when participants were interviewed using a combination of the ‘report everything’ and ‘mental reinstatement’ components of the CI, their recall was significantly higher than when using just one individual component or the control condition
• support research evidence COUNTER

  however, Kohnken et al. found that the CI actually just increased the quantity of information, but not the quality. there was an increase of correct information but also a 61% increase in incorrect information (false positives) when the enhanced CI was used compared to a standard interview
• limitations

  • it is time consuming
  • comparisons are difficult
• it is time-consuming

  the CI requires a lot fo time and training to implement it

  Kebbell and Wagstaff report a problem with the CI in practice:

  • the interview tales a lot more time than a standard interview- more time needed to establish rapport with the witness and allow them to relax
  • CI requires special training and many forces have not been able to provide more than just a few hours

  unlikely that the use of CI technique has been widespread
• comparisons are difficult

  it is hard to establish the effectiveness of the CI when it is used in the real world as it is not just one ‘procedure’ but a collection of related techniques

  Thames Valley Police use a version that does not include the ’changing perspectives’ component. other police forces have tended to use only the ‘reinstate context’ and ‘report everything‘ components

  it is hard to establish the overall effectiveness of the technique when using all components