If you're cramming for a test or have an important date to remember, you might find this simple tip useful: close your eyes.

Researchers from the University of Surrey found that eyewitnesses have a better chance of remembering details about a crime when they close their eyes. The team conducted two experiments with 178 people.

In the first experiment, they asked participants to watch a film in which an electrician stole items from homes where he did jobs. They then split viewers into four groups: the subjects were asked to either close their eyes or keep them open, or they built up a good relationship with the interviewer or did not build up a relationship with the interviewer.

The team found that when the participants closed their eyes, they were able to remember 23 percent more information than the people in the other groups. Having a good relationship with the interviewer also helped people answer more questions about the crime correctly, but if the person closed his or her eyes, the recall was effective regardless of the rapport the person felt with the interviewer.

In the second experiment, the conditions were the same as before but with an additional twist: there was audio along with the video. The researchers found that closing the eyes helped the participants remember both audial and visual information.

The researchers found that closing your eyes during an investigation is likely to make you feel less comfortable unless you have built up a good rapport with the questioner. Participants who had not built a rapport with their interrogator said that they felt uncomfortable closing their eyes in both experiments. However, participants who had built a rapport said that they felt more comfortable when they closed their eyes.

"It is clear from our research that closing the eyes and building rapport help with witness recall. Although closing your eyes to remember seems to work whether or not rapport has been built beforehand, our results show that building rapport makes witnesses more at ease with closing their eyes. That in itself is vital if we are to encourage witnesses to use this helpful technique during interviews," said Dr. Robert Nash, lead author of the study.

Can this revelation help people remember other types of information in other circumstances? It should, according to Nash.

"The mechanisms we identified ought to apply to other contexts, for example trying to remember details of a lecture," Nash said.