From Robert Louis Stevenson to Mendeleev: sleeping on it does make a difference

The old adage "let's sleep on it" has a scientific basis: a study shows people really do have deeper insights into difficult problems after a good night's rest.

Many of the greatest artistic and scientific achievements are said to have come after slumber and now researchers have demonstrated that a period of profound sleep helps to consolidate memory in such a way that it enables a person to wake up with a fresh ability to gain a significant insight into something that might otherwise prove inscrutable. Robert Louis Stevenson is said to have been inspired to write scenes in his novel The Strange Case of Dr Jekyll and Mr Hyde after sleeping, while Dmitri Mendeleev said that he formulated the critical rule for the periodic table of chemical elements after sleeping deeply.

Scientists believe that sleep can do something more for us than merely provide rest - it can help the human brain to structure the thought processes of memory. The study used a psychological test that measured the time it took for experimental volunteers to become conscious of a hidden rule.

Some 60 per cent of those who had slept gained insight into the hidden rule while only 22 per cent of those who remained awake managed to discover it, the study published in the journal Nature showed. Pierre Maquet and Perrine Ruby of the University of Liege in Belgium, write: "Wagner et al give us good reason to fully respect our periods of sleep, especially given the current trend to recklessly curtail them."