Why do babies fall asleep when they're rocked? All parents know it works, and have their own special way of moving with an irritable sleepy baby - in a sling, up and down, side to side, in the car. Recent research on rocking doesn't answer the baby question, but shines a light on the salutary effect it can have on grown-ups.
Anyone who's experienced sleeping on a boat will wax lyrical about it - the special soothing sensation of being rocked to sleep by gently lapping water. There's even a company that specializes in offering floating accommodations. And novelists from Graham Greene to Paul Theroux have encapsulated the romance of the night train - boarding at bedtime, swaying in your berth with a clickety-clack lullaby, waking refreshed and ready to explore the completely different place you are now in. There is obviously something to be said for moving gently while sleeping.
任何在船上睡过觉的人都会对其热情吹捧--船儿轻轻拍打水面带来一种舒缓的入睡感。甚至有公司专门提供浮动住宿服务。格雷厄姆·格林（Graham Greene）和保罗·塞鲁克斯（Paul Theroux）等小说家们已将夜间列车的浪漫故事融入了摇摇晃晃的摇篮曲--睡前登船、躺在卧铺上摇晃，第二天醒来精神焕发，准备探索这一截然不同的所处地。显然，睡觉时的轻微晃动是有益的。
Some research was undertaken in 2011 which looked at how napping was improved by rocking to and fro, which inspired a group of scientists from the Department of Neuroscience at the University of Geneva in Switzerland to carry out this new research on a full night's shut-eye.
Eighteen healthy young volunteers spent two nights sleeping in the lab and playing memory games with pairs of words, while researchers tracked their brain activity with an electroencephalogram. One of the nights was spent in a traditional bed, while the second was spent gently rocking in a bed the scientists had rigged up. The special bed swayed approximately four inches each way over the period of eight seconds.
The results show that even adults benefit from being rocked while they sleep. The subjects took an average of seven minutes' less time to fall asleep in the rocking bed than they did in the steady bed, they spent more time in deep non-REM sleep, and they woke less often.
结果表明，即使是成年人也能在摇晃中睡个好觉。受试者在摇晃床上入睡的时间比在平稳床上入睡的时间平均少7分钟，他们深度非快速眼动睡眠（deep non-REM sleep）的时间更久，醒来的频次也更少。
After rocking through the night, they also had a better recall of the word pairs they had learned the night before, suggesting that better sleep improves memory.