When interviewing witnesses to a crime, police interviewers seek to maximize the amount of information that a cooperating eyewitness can give them so that they can generate leads to follow, confirm or disconfirm alibis, and so forth. One method for eliciting witness might otherwise provide is the cognitive interview.
Developed by psychologists and adopted by police forces around the world, the cognitive interview combines cognitive techniques known to improve recall, such as multiple retrieval attempts, with communication strategies developed by social psychologists, such as conversation-management skills and techniques for building rapport between interviewer and interviewee. The general consensus is that this training, and even trained officers often deviate from the procedures specified in the cognitive interview training.
An alternative to the cognitive interview is hypnosis. Indeed, hypnotic investigative interviewing was a precursor to the cognitive interview. However, even though the techniques involved are much less complex, the evidence suggests that overall accuracy, as determined by the proportion of correct to incorrect responses, is not generally improved with hypnosis; in There are other practical difficulties, most notably that not all witnesses are susceptible to hypnosis.
For police interviewers, the ideal method for eliciting additional information from an eyewitness would be one that requires no special training for the interviewer, that can be applied to the entire population of potential witnesses, and that has a positive effect on correct memory reports, with no corresponding increase in false details achieved with no increase in errors, no specialist training, and no greater complexity of interviewing technique.
What this question is testing
Topic
The author is comparing three different ways police can interview a cooperative witness to get more information out of them — and quietly working toward the conclusion that the third one is the best.
Framework
Problem/Solution. The author isn't arguing against an opponent — they're showing why the existing tools have drawbacks and then introducing a tool that doesn't.
Main Point
Here's the simpler version: getting witnesses to close their eyes during recall — "instructed eye-closure" — gives you about the same boost in recall as the much fancier cognitive interview, without any of its downsides. And it doesn't have hypnosis's problems either. So it looks like the ideal technique.
P1: Why this matters
Police interviewers want as much usable information as a cooperative witness can give. The cognitive interview is one tool that's been built to help.
P2: The cognitive interview — works, but it's a lot
It really does help witnesses recall more without making them less accurate. The catch: it's elaborate, takes serious training, and even officers who are trained tend to fall back on shortcuts in real interviews.
P3: Hypnosis — easier, but messier
Hypnosis is much simpler to learn, but the research isn't kind to it. Overall accuracy doesn't improve, and witnesses become more confident in everything they say — including the wrong stuff. Plus, not everyone can even be hypnotized.
Reading along? Open the full official question in LawHub — we show a fragment here and keep the reasoning in our own words.