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 information over and above what a cooperative 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 package has proven successful in increasing the number of details recalled by witnesses, with little impact on the number of incorrect details reported (neither increasing nor decreasing overall accuracy). However, a problem associated with the cognitive interview is that it is a complex procedure, requiring substantial training to learn and a long time to conduct. Because of this complexity, not all officers receive 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 fact, sometimes it may deteriorate. Hypnosis may also give rise to a "false confidence" effect, whereby witnesses are more confident in their reports generally, including reports of incorrect information. 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 reported. Research suggests that such a method may in fact be available. Encouraging eyewitnesses to close their eyes during recall attempts is a technique that is common to both hypnosis and the cognitive interview. Recent studies demonstrate that instructed eye-closure can benefit recall for both visual and auditory materials, for events witnessed on video, and for events witnessed through live interactions. These studies indicate an improvement over hypnotic interviewing, with no problems of participant dropout because of lack of hypnotic susceptibility. More significantly, instructed eye-closure by itself appears to improve witness recall to a degree equivalent to that demonstrated by the cognitive interview. And the benefits of eye-closure are achieved with no increase in errors, no specialist training, and no greater complexity of interviewing technique.