If you've lost your keys, or forgotten where you parked your car, take a minute to close your eyes. And hopefully you'll remember.

According to researchers from the University of Surrey in the UK, closing your eyes can improve your short-term memory, and they say the technique could prove useful for eyewitnesses to crimes who are being questioned by police.   

Closing one's eyes will "help people visualise the details of the event they are trying to remember," lead researcher Robert Nash told the BBC. He added that it could "help focus on audio information, too." 

The researchers showed 178 participants a silent film clip of an electrician entering a home, performing a job, and then stealing possessions. 

The participants were split into groups: half kept their eyes open, and the other half closed their eyes. (These groups were further subdivided into people with whom the researchers had and hadn't "built up a rapport" with).

The participants were then asked questions about details in the film (such as "what was written on the front of the van?") to test their recall. 

The group that shut their eyes answered 71 percent of the questions correctly, while the group that kept their eyes open answered only 48 percent of the questions. 

In a second experiment, researchers showed a clip from a British crime show with sound, depicting an elderly man being attacked in his home. Again, the group that closed their eyes had a better recall percentage - not only for visual information, but also audial information. 

Building rapport with the participants also led to more correct answers, the study found. 

The results were published in the journal Legal and Criminological Psychology. 

Previous studies have also shown that witnesses can improve their recall of relevant details by closing their eyes (without any increase in the recall of false information). It is suspected that this is because it helps people block out distractions. 

Victim and eyewitness testimony is considered to be the best predictor when it comes to solving a crime.  

A number of interview methods exist to help police get reliable information, some of which employ the technique of asking people to shut their eyes. 

However, police often receive very little training in the art of interviewing cooperative witnesses. 

Questioning people about crimes can be tricky business. Another study published this week showed that innocent people can be questioned by police in such a way that they end up convincing themselves that they've committed a serious crime as a teenager. This false memory was generated by three hours in a "friendly interview environment, where the interviewer introduces a few wrong details and uses poor memory-retrieval techniques," the authors said. 

The researchers from the University of Surrey say their results highlight the importance of building up rapport.

"It is clear from our research that closing the eyes and building rapport help with witness recall," said Nash in a press release. 

"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," he said. "That in itself is vital if we are to encourage witnesses to use this helpful technique during interviews."

Sources: BBC