Dement and others hope that recent research on the consequences of our national sleep deficit will persuade society to change - psychologically, culturally, even legislatively. "We need to recognize that as a culture we are exactly where we were with drinking and driving in the 1950s," says David Dinges, chief of the Division of Sleep and Chronobiology at the University of Pennsylvania. "People used to think it was O.K to drink to drunkenness, then get in a car. Finally someone said, no, enough.

And we've gone all the way from having a civil issue to a serious criminal issue. We need a similar evolution recognizing another large biological impairment, the adequacy of one's sleep, which is an impairment that can afflict anybody and that plays a role in how safe we are."

"There were no sleep disorders before 1970," says Dement, and what he means is there was precious little science. Now instead of groping in the dark, sleep researchers know the nature and extent of the problem - and at least some of the solutions. They understand that pathological sleep patterns cheat a person out of needed rest; that snoring is often a sign of a dangerous sleep impairment; that a car crash without skid marks was probably caused by someone asleep at the wheel.

There have also been major breakthroughs in the diagnosis and treatment of sleep disorders. Insomnia, which once was seen as a manifestation of depression to be fought with anti-depressants, is now treated with drugs that adjust neurotransmitters. Sleepwalking and night-screaming, long assumed to be psychological syndromes, are now considered physiological problems.

WHY DOES A CAT NAP?
Fido naps all day, and Kitty falls asleep hundreds of times; Cows get barely three hours of sleep, rabbits get eight; mice pile up 13; and the sloth, mascot of all long-sleepers, needs 20. Evolution bequeaths sleep schedules that fit the species; only man tampers with his needs. Not surprisingly, the sleep-wake cycle of apes is closest to that of humans.
As Stanley Coren wrote in his 1996 study, Sleep Thieves, since "apes and monkeys... sleep 10 hours or more each day, we might conclude that human beings are sleeping around two and a half hours less than they should."