人類進化結果睡眠更少,更好
Humans are efficient sleepers, and that's why we need less sleep - seven hours - compared to as much as 14 hours a day for our closest animal relatives,
人類的睡眠很有效，這也是爲什麼我們睡得更少，一天只睡7個小時而不是離我們最近的物種所需的多達14個小時。
Researchers at Duke University compiled a database of sleep patterns of hundreds of mammals, including 21 primate species. They found that not only do humans need less sleep than chimps, macaques and lemurs, we spend a greater percentage of our slumber in the deeper, more restorative stages of sleep.
美國杜克大學的研究人員建立了一個幾百種哺乳動物睡眠規律的數據庫，其中包括21種靈長類動物。他們發現，人類睡眠時間不僅比黑猩猩、獼猴和狐猴要少，而且更多時間是沉睡在更深、更有恢復作用的階段。
That might not seem surprising in this age of electric lights and round-the-clock activities, but co-author David Samson says this shift began long before we developed artificial lighting. He traces it back to when human ancestors left their nests in the trees for sleeping on the ground.
在這個有電燈和通宵工作的時代這也許並不令人驚訝。但是這份報告的共同作者大衛·薩姆森說，睡眠的這種變化早在我們發明人工照明之前就開始了。他將這一變化追溯到人類祖先離開樹巢開始睡在地上的時候。
The need to sleep near fire and in larger groups for warmth and safety could have allowed these early humans to get the most out of their sleep in the shortest possible time. He notes that also left more time for other activities, like learning new skills.
由於睡覺時需要靠近火和更大的人羣保持溫暖和安全，這可能使得早期人類儘可能在最短時間內睡得最好。薩姆森提到這也留給人類更多的時間做其他活動，比如學習新技能。
