Instructed eye closure and reliable eyewitness recall

Police want cooperating witnesses to remember as much useful information as possible. A detail might provide a new lead or establish that a suspect was somewhere else when a crime occurred. The practical question is how to get that information without also getting more mistakes. More confident or more talkative witnesses aren't necessarily more reliable ones.

The first option is the cognitive interview. Think of it as a package: memory techniques, such as trying to retrieve a memory more than once, combined with communication skills that help the interviewer build rapport. The package gets witnesses to recall more details. But keep the result precise. The writer says it neither increases nor decreases overall accuracy; we shouldn't turn a benefit in the amount recalled into a general claim that everything witnesses say becomes more trustworthy.

So why not use it every time? It takes substantial training and a long time to conduct. Some officers never receive the training, and even trained officers don't always follow the procedures. Those are two different obstacles. Paying to train everyone could address the first without fixing the second. As a practical illustration, an elaborate interview may be harder to justify for a minor shoplifting report than for a serious investigation. The point is the demand on time and resources, not a recommendation to neglect any particular crime.

Could hypnosis offer an easier alternative? Its techniques are less complex, but simpler doesn't automatically mean better. The proportion of correct to incorrect reports generally doesn't improve and may get worse. Hypnosis can also produce false confidence: a witness might insist, “I'm sure that's who I saw,” even when the identification is wrong. Asking how sure the witness is wouldn't resolve that problem. And some people aren't susceptible to hypnosis at all.

By now, we can see what a better method would need to accomplish. It should be easy for the interviewer, usable with all potential witnesses, and capable of drawing out more correct information without adding false details. Those criteria respond to the problems we've just encountered; they aren't an unrelated wish list.

The proposed solution is surprisingly simple: ask the witness to close their eyes while trying to remember. Both hypnosis and the cognitive interview already include that technique. The new question is whether this one piece can do the useful work of the larger package on its own.

The studies suggest that it can. Eye closure benefits recall of things heard as well as things seen, and of events experienced in person as well as on video. It doesn't depend on susceptibility to hypnosis. Most significantly, eye closure alone appears to improve recall as much as the whole cognitive interview, with no increase in errors. An interviewer can give that instruction without specialist training or a more complicated interview.

That is why the ending matters more than simply observing that two older techniques share a feature. We started with a demanding method and a simpler but problematic alternative. Now we have evidence that a small component can preserve the recall benefit while avoiding those practical obstacles. The claim remains tied to what these studies suggest; we haven't established perfect memory or the elimination of every possible error.