Every so often scientists produce findings that, while considered controversial by their peers, confirm something the rest of us suspected all along, writes Frank McNally.
So it is with Dr Olaf Lahl of the University of Dusseldorf, who has discovered evidence that even very short periods of sleep dramatically improve human brain function. In a study, students he asked to memorise a list of words were discovered to have much better recall an hour later if allowed a five-minute nap in the interim.
This points to the possiblity, Dr Lahl told New Scientist magazine - and here is where other experts disagree with him - that the mere act of falling asleep, rather than being asleep, is what counts.
We all know that a mid-day nap, however short, can be inordinately refreshing. Minute-for-minute, it seems to do a much better job than the six or eight or 10 hours rest you have at night. And such micro-sleep is all the more effective when it is spontaneous, creeping up on you at the desk, or on the train (and not - it is to be hoped - at the wheel of your car).
The problem is that, next to speaking in public, the thought of falling asleep in public is a source of dread to many people. There are good reasons for this, apart from the deep-seated human fear of being seen to drool. The fact is that society stigmatises public sleeping: unless you suffer from narcolepsy and display a doctor's certificate to that effect, it is considered a sign of weakness.
Should you have the double misfortune of (a) falling asleep in public while (b) being famous, you can also be sure that some pesky press photographer or "citizen journalist" will be on hand to record your shame for a wider audience.
Illustrating the point, YouTube currently features an admittedly very entertaining video of Bill Clinton nodding off during a Baptist church ceremony last month. Not only was this a gift to press photographers. The former US president also earned the gratitude of headline writers by doing it at a Martin Luther King Day commemoration - cueing several variations of the immortal "I Have a Dream". It was the classic, furtive nap. Unfortunately, Clinton was on the podium at the time, just behind the speaker, who was clearly boring the tail-end off everyone in the room. Just as clearly, Clinton needed to lie down for a while. But, this being impossible, he propped his head on his hand for a few moments and closed his eyes, as if in thought - a ruse he might have got away with except that, inevitably, his elbow slipped off the arm of the chair, causing him to wake with a visible start.
A few moments later, he was gone again. When he woke the second time, old trouper that he is, he instinctively nodded in agreement, as if the speaker had just made a particularly good point (which he had not). This is a popular tactic among politicians - "nodding on" you could call it - although it didn't quite work on this occasion.
Republicans were quick to point out that Clinton had previously nodded off during Ronald Reagan's funeral. Perhaps more damaging to his wife's presidential campaign, he once did it at a New York Mets baseball game as well. But in his defence, it must be said he is an avowed napper, on record as saying that a few minutes' sleep in the middle of the day is crucial to his workrate.
For most of us, the workplace is precisely where the urge to nod off will overtake us. Unfortunately, napping during company time is particularly problematic. Workers are hard-wired to pretend they're busy even when doing nothing; and bosses are equally prone to wanting their staff to maintain at least the appearance of consciousness at all times.
But attitudes may be changing. The Wall Street Journal last year highlighted the case of a New York publisher who actively encourages his 200 employees to catnap at work, under the desk if necessary. It added to this triumph for the napping movement that his name was "Peter Workman". Thus staff at the soberly-titled Workman Publishing were leading a fight-back against the macho dictum: "Snooze and you lose". If Dr Lahl is correct, far from causing you to lose anything, the ability to fall asleep at key moments could be the key to maximising brain performance.
Another specialist, Dr Robert Stickgold of Harvard University agrees - explaining that, just before sleep, the brain replays recent events, causing us to have dreamlike sensations and "crazy" thoughts. It's as if our minds are "sifting through new material to figure out what to work on", he says. And it could be this short "hypnagogic" state, rather than prolonged sleep, that facilitates good recall.
Some of the wisest people among us - elderly judges - have always known this instinctively. So the next time you see one nodding off in the middle of a defence lawyer's summing-up, don't think of it as the unfortunate consequence of advanced age and a heavy lunch. Neither is it grounds for an appeal by the losing side. On the contrary, the judge is undergoing a self-induced hypnagogic state, designed to marshal the facts of a complex case - all the better to deliver a Solomon-like judgment.