Stop press: you're less likely to remember things when you're tired. That's this week's eye-opening revelation from the University of Geneva, where Dr Sophie Schwartz gave a group of 32 volunteers a series of tasks, only to find out that those who had slept properly performed better. Next week: people are more likely to pass their driving test when they aren't being hit in the face with an iron.
Schwartz couched the findings in suitably soporific terms. "A period of sleep following a new experience can consolidate and improve subsequent effects of learning from the experience," she yawned (probably). "This improvement comes from changes in brain activity in specific regions that code for relevant features of the learned material."
Respondents in the study were asked to follow a moving dot on a computer screen with a joystick, and also to remember unknown faces. Those who then had a night of restful sleep improved at the tasks, giving hope to fatigued hitmen everywhere.
But scientists can't agree on how much sleep is necessary for improvement to take place. One recent poll of 4,000 adults in the UK found only one in five sleep for eight hours a night, eight hours being the apparent optimum total. However, sleep expert Daniel Kripke recently told Time magazine that the correct figure is between six-and-a-half and seven-and-a-half hours, and that "people who sleep eight hours or more ... they don't live quite as long."
Still, Schwartz's assertion that sleep helps the brain can't be disputed. For examples of lack of sleep having a detrimental effect on both memory and judgment, you only have to look at the US presidential race. Hillary Clinton insisted in March that she was "sleep-deprived" when she fabricated her report about landing in Bosnia under sniper fire - an incident which caused millions of Americans to wonder: "What if you're sleep-deprived and you accidentally push the button?"
In the same month, her fellow hopeful John McCain supported a Bush veto on a bill which proposed banning extreme interrogation tactics by the CIA, among them sleep-deprivation. As sleep-deprivation was used by the North Vietnamese during McCain's time as a PoW, maybe its effects caused the resolutely anti-torture Republican to forget how harsh it was.
But you don't have to be a politician to take advantage of the study's findings. Its conclusion that sleep lets the brain "consolidate learned experiences and harden up memories which otherwise might fade in time" surely means that, whenever we have a bad experience, we have to stay awake for longer to help our brain blot it out - like alcohol, but without the embarrassment and expense. Whether you've been humiliated at work, rejected by the object of your affections, or have merely walked into a lamp-post in front of the neighbours, lack of sleep will reportedly weaken connections between nerve cells in the brain, preventing you from remembering events in painful detail.
Students can argue that sleeping during the day is crucial to learning, and, if accused of laziness, can quote sleep expert Dr Neil Stanley: "Sleep is not just a waste of time, it is a very active time and we need it for things like memory and learning." Similarly, employees can now ask for a 20-minute power nap after being taught a new skill, explaining that they need to allow their brain to consolidate the new information.
And, most usefully, the study provides a handy excuse for bleary post-coital men everywhere, who after lovemaking can now say: "Sleeping? No dear, of course I'm not sleeping. I'm just preserving the memory of tonight for years to come."
· Ariane Sherine is a television comedy writer