The Cognitive Interview

It's an undeniable fact that eyewitnesses sometimes fail to remember things that are crucial for a criminal investigation-for example, facts that might help identify the perpetrator. Can we take any steps, therefore, to help witnesses remember more, to maximize the information we get from them? One promising approach is the cognitive interview. In this technique, witnesses are led to approach the event to be remembered from more than one perspective, so that, for example, they're encouraged to recount the event from its start to its end, and then in reverse sequence, from the end back to the beginning. The witnesses are also led to reconstruct the environmental and personal context of the event, in essence, putting themselves back into the same frame of mind that they were in at the time of the crime.

Evidence suggests that the cognitive interview helps both adult and child witnesses to remember more about a previously experienced event, and, importantly, does so without encouraging false memories. It is gratifying, then, that the cognitive interview has been adopted by a number of police departments as their preferred interview technique.

Why does the cognitive interview technique work? As we have discussed, not every gap in our recollection reflects a "memory failure." Instead, we sometimes cannot remember things simply because we didn't note them in the first place, and so no record of the desired information was ever placed in long-term storage. But in other cases, gaps in our recollection have a different source: retrieval failure. The desired information is in memory, but we're unable to find it. In the terms we used in Chapter 8 of the textbook, activation does not reach the relevant nodes, and so the information is never located.

The likelihood of retrieval failure is reduced, though, if multiple retrieval cues are available. Each cue will trigger its own nodes, leading to a retrieval path. By trying multiple paths, we maximize the chances of finding one that's well enough established to lead us to the target materials. In addition, with multiple cues simultaneously activated, the target nodes in memory can receive activation from several sources at the same time, and this too makes retrieval more likely. We've also discussed the fact that context reinstatement can be a powerful aid to remembering: By putting someone back into the same mental context that they were in during the target event, we are likely to activate thoughts and ideas that are associated with that context. Activation can then spread from the nodes representing these ideas to the target materials.

Note, by the way, that hypnosis can also be used to reinstate an earlier context. If this were all that hypnosis did, then hypnosis, like the cognitive interview, would be a useful tool for police interviewers. Unfortunately, though, hypnosis also has several other effects-such as making someone more vulnerable to suggestion and less able to discriminate genuine recollection from after-the-fact reconstruction. As a result, the benefits of hypnosis are outweighed by the problems.

Overall, it's really no surprise that the cognitive interview is effective; the interview simply capitalizes on mechanisms that we already know to be helpful. More important, though, the cognitive interview provides a clear example of how we can use what we know about memory to aid anyone-including law-enforcement professionals-who needs to draw as much information from memory as possible.

To learn more about this topic in cognitive psychology and the law:

See, in the textbook chapter, pages 254-257

Holliday, R. E., & Albon, A. J. (2004). Minimising Misinformation Effects in Young Children with Cognitive Interview Mnemonics. Applied Cognitive Psychology, 18, 263-281.

Milne, R., & Bull, R. (2002). Back to basics: A componential analysis of the original cognitive interview mnemonics with three age groups. Applied Cognitive Psychology, 16, 743-753.

Davis, M. R., McMahon, M., & Greenwood, K. M. (2005). The Efficacy of Mnemonic Components of the Cognitive Interview: Towards a Shortened Variant for Time-Critical Investigations. Applied Cognitive Psychology, 19, 75-93.

Koehnken, G., Milne, R., Memon, A., & Bull, R. (1999). The cognitive interview: A meta-analysis. Psychology, Crime & Law, 5, 3-27.