美国国家公共电台 NPR--I usually wake up just ahead of my alarm. What's up with that?

I usually wake up just ahead of my alarm. What's up with that?

Transcript¹

Maybe this happens to you sometimes, too:

You go to bed with some morning obligation on your mind, maybe a flight to catch or an important meeting. The next morning, you wake up on your own and discover you've beat your alarm clock by just a minute or two.

What's going on here? Is it pure luck? Or perhaps you possess some uncanny ability to wake up precisely² on time without help?

It turns out many people have come to Dr. Robert Stickgold over the years wondering about this phenomenon.

"This is one of those questions in the study of sleep where everybody in the field seems to agree that's what's obviously true couldn't be," says Stickgold, who's a cognitive³ neuroscientist at Harvard Medical School and Beth Israel Deaconess Medical Center.

Stickgold even remembers bringing it up to his mentor⁴ when he was just starting out in the field — only to be greeted with a dubious⁵ look and a far from satisfactory explanation. "I can assure you that all of us sleep researchers say 'balderdash, that's impossible,' " he says.

And yet Stickgold still believes there is something to it. "This kind of precision waking is reported by hundreds and thousands of people,'" he says, including himself. "I can wake up at 7:59 and turn off the alarm clock before my wife wakes up." At least, sometimes.

Of course, it's well known that humans have an elegant and intricate system of internal processes that help our bodies keep time. Somewhat shaped by our exposure to sunlight, caffeine, meals, exercise and other factors, these processes regulate our circadian rhythms throughout the roughly 24-hour cycle of day and night, and this affects when we go to bed and wake up.

If you are getting enough sleep and your lifestyle is aligned⁶ with your circadian rhythms, you should typically wake up around the same time every morning, adjusting for seasonal⁷ differences, says Philip Gehrman, a sleep scientist at the University of Pennsylvania.

But that still doesn't adequately explain this phenomenon of waking up precisely a few minutes before your alarm, especially when it's a time that deviates⁸ from your normal schedule.

"I hear this all the time," he says. "I think it's that anxiety about being late that's contributing."

Scientists get curious — with mixed results

Actually, some scientists have looked into this enigma⁹ over the years with, admittedly, mixed results.

For example, one tiny, 15-person study from 1979 found that, over the course of two nights, the subjects were able to wake up within 20 minutes of the target more than half of the time. The two subjects who did the best were then followed for another week, but their accuracy quickly plummeted¹⁰. Another small experiment let the participants choose when they'd get up and concluded that about half of the spontaneous awakenings were within seven minutes of the choice they'd written down before they went to sleep.

Other researchers have taken more subjective¹¹ approaches, asking people to report if they have the ability to wake up at a certain time. In one such study, more than half of the respondents said they could do this. Indeed, Stickgold says it's quite possible that "like a lot of things that we think we do all the time, we only do it once in a while."

OK, so the scientific evidence isn't exactly overwhelming.

But there was one intriguing¹² line of evidence that caught my eye, thanks to Dr. Phyllis Zee, chief of sleep medicine at Northwestern University Feinberg School of Medicine.

Stress hormones¹⁴ might play a role

In the late '90s, a group of researchers in Germany wanted to figure out how expecting to wake up influenced what's known as the HPA axis¹⁵ — a complex system in the body that deals with our response to stress and involves the hypothalamus, the pituitary gland¹⁶ and the adrenal glands¹⁷.

Jan Born, one of the study's authors, says they knew that levels of a hormone¹³ that's stored in the pituitary gland, called ACTH, start increasing in advance of the time you habitually¹⁸ wake up, which in turn signals the adrenal glands to release cortisol, a so-called "stress hormone" that helps wake you up, among other things.

"In this context, we decided¹⁹ to try it out and it came out actually as hypothesized," says Born, who's now a professor of behavioral neuroscience at the University of Tubingen, in Germany.

Here's what Born and his team did: They found 15 people who would normally wake up around 7 or 7:30 a.m., put them in a sleep lab and took blood samples over the course of three nights.

The subjects were divided into three different groups: Five of them were told they'd have to get up at 6 a.m.; others were assigned 9 a.m.; the third group were given a 9 a.m. wake-up time, but were then unexpectedly awakened²⁰ at 6 a.m.

Born says a clear difference emerged as their wake-up time approached.

The subjects who anticipated waking up at 6 a.m. had a notable rise in the concentration of ACTH, starting about 5 a.m. It was as if their bodies knew they had to get up earlier, says Born.

"This is a good adaptive preparatory response of the organism," says Born with a chuckle²¹, "because then you have enough energy to cope with getting up and you can make it until you have your first coffee."

That same rise in stress hormones before waking up wasn't recorded in members of the group who did not plan to get up early, but were surprised with a 6 a.m. wake-up call. The third group — the one assigned a 9 a.m. wake-up time, didn't have a pronounced rise in ACTH an hour before getting up. (Born says that suggests that this was simply too late in the morning to see the same effect.)

Born's experiment wasn't actually measuring whether people would ultimately wake up on their own before a predetermined time, but he says the findings raise some intriguing questions about that phenomenon. After all, how did their bodies know that they would have to get up earlier than normal?

"It tells you that the system is plastic, it can adapt, per se, to shifts in time," he says. And it also suggests that we have some capacity to exploit this "system" while awake. That idea isn't entirely²² foreign in the field of sleep research, he says.

A "scientific mystery" still to be solved

"It is well known that there is a kind of mechanism²³ in the brain that you can use by volition²⁴ to influence your body, your brain, while it is sleeping," says Born. He points to research showing that a hypnotic suggestion can help make someone sleep more deeply.

Zee at Northwestern says there are probably "multiple biological systems" that could explain why some people seem capable of waking up without an alarm clock at a given time. It's possible that the worry about getting up is somehow "overriding²⁵" our master internal clock, she says.

"This paper really is neat because it shows that your brain is still working," she says.

Of course, exactly how it's working and to what extent you can rely on this enigmatic internal alarm system remains²⁶ a big, unanswered question. And while none of the sleep researchers I spoke²⁷ to are planning to ditch their alarm clocks, Harvard's Stickgold says he's not ready to dismiss the question.

"It's a true scientific mystery," he says, "which we have a lot of." And as in many fields, he adds, when facing a mystery, it would be arrogant²⁸ "to assume that since we don't know how it could happen, that it can't."

1 transcript   

n.抄本，誊本，副本，肄业证书

参考例句：

• A transcript of the tapes was presented as evidence in court.一份录音带的文字本作为证据被呈交法庭。
• They wouldn't let me have a transcript of the interview.他们拒绝给我一份采访的文字整理稿。

2 precisely   

adv.恰好，正好，精确地，细致地

参考例句：

• It's precisely that sort of slick sales-talk that I mistrust.我不相信的正是那种油腔滑调的推销宣传。
• The man adjusted very precisely.那个人调得很准。

3 cognitive   

adj.认知的，认识的，有感知的

参考例句：

• As children grow older,their cognitive processes become sharper.孩子们越长越大，他们的认知过程变得更为敏锐。
• The cognitive psychologist is like the tinker who wants to know how a clock works.认知心理学者倒很像一个需要通晓钟表如何运转的钟表修理匠。

4 mentor   

n.指导者，良师益友；v.指导

参考例句：

• He fed on the great ideas of his mentor.他以他导师的伟大思想为支撑。
• He had mentored scores of younger doctors.他指导过许多更年轻的医生。

5 dubious   

adj.怀疑的，无把握的；有问题的，靠不住的

参考例句：

• What he said yesterday was dubious.他昨天说的话很含糊。
• He uses some dubious shifts to get money.他用一些可疑的手段去赚钱。

6 aligned   

adj.对齐的，均衡的

参考例句：

• Make sure the shelf is aligned with the top of the cupboard.务必使搁架与橱柜顶端对齐。

7 seasonal   

adj.季节的，季节性的

参考例句：

• The town relies on the seasonal tourist industry for jobs.这个城镇依靠季节性旅游业提供就业机会。
• The hors d'oeuvre is seasonal vegetables.餐前小吃是应时蔬菜。

8 deviates   

v.偏离，越轨( deviate的第三人称单数 )

参考例句：

• The boy's behavior deviates from the usual pattern. 这个男孩子的举止与一般人不同。 来自《简明英汉词典》
• The limit occurs when the ordinate deviates appreciably from unity. 这个限度发生在纵坐标明显地从单位1偏离的时候。 来自辞典例句

9 enigma   

n.谜，谜一样的人或事

参考例句：

• I've known him for many years,but he remains something of an enigma to me.我与他相识多年，他仍然难以捉摸。
• Even after all the testimonies,the murder remained a enigma.即使听完了所有的证词，这件谋杀案仍然是一个谜。

10 plummeted   

v.垂直落下，骤然跌落( plummet的过去式和过去分词 )

参考例句：

• Share prices plummeted to an all-time low. 股票价格暴跌到历史最低点。
• A plane plummeted to earth. 一架飞机一头栽向地面。 来自《简明英汉词典》

11 subjective   

a.主观(上)的，个人的

参考例句：

• The way they interpreted their past was highly subjective. 他们解释其过去的方式太主观。
• A literary critic should not be too subjective in his approach. 文学评论家的看法不应太主观。

12 intriguing   

adj.有趣的；迷人的v.搞阴谋诡计(intrigue的现在分词)；激起…的好奇心

参考例句：

• These discoveries raise intriguing questions. 这些发现带来了非常有趣的问题。
• It all sounds very intriguing. 这些听起来都很有趣。 来自《简明英汉词典》

13 hormone   

n.荷尔蒙，激素，内分泌

参考例句：

• Hormone implants are used as growth boosters.激素植入物被用作生长辅助剂。
• This hormone interacts closely with other hormones in the body.这种荷尔蒙与体內其他荷尔蒙紧密地相互作用。

14 hormones   

n. 荷尔蒙，激素 名词hormone的复数形式

参考例句：

• This hormone interacts closely with other hormones in the body. 这种荷尔蒙与体內其他荷尔蒙紧密地相互作用。
• The adrenals produce a large per cent of a man's sex hormones. 肾上腺分泌人体的大部分性激素。

15 axis   

n.轴，轴线，中心线；坐标轴，基准线

参考例句：

• The earth's axis is the line between the North and South Poles.地轴是南北极之间的线。
• The axis of a circle is its diameter.圆的轴线是其直径。

16 gland   

n.腺体，(机)密封压盖，填料盖

参考例句：

• This is a snake's poison gland.这就是蛇的毒腺。
• Her mother has an underactive adrenal gland.她的母亲肾上腺机能不全。

17 glands   

n.腺( gland的名词复数 )

参考例句：

• a snake's poison glands 蛇的毒腺
• the sebaceous glands in the skin 皮脂腺

18 habitually   

ad.习惯地，通常地

参考例句：

• The pain of the disease caused him habitually to furrow his brow. 病痛使他习惯性地紧皱眉头。
• Habitually obedient to John, I came up to his chair. 我已经习惯于服从约翰，我来到他的椅子跟前。

19 decided   

adj.决定了的，坚决的；明显的，明确的

参考例句：

• This gave them a decided advantage over their opponents.这使他们比对手具有明显的优势。
• There is a decided difference between British and Chinese way of greeting.英国人和中国人打招呼的方式有很明显的区别。

20 awakened   

v.（使）醒( awaken的过去式和过去分词 )；（使）觉醒；弄醒；（使）意识到

参考例句：

• She awakened to the sound of birds singing. 她醒来听到鸟的叫声。
• The public has been awakened to the full horror of the situation. 公众完全意识到了这一状况的可怕程度。 来自《简明英汉词典》

21 chuckle   

vi.／n.轻声笑，咯咯笑

参考例句：

• He shook his head with a soft chuckle.他轻轻地笑着摇了摇头。
• I couldn't suppress a soft chuckle at the thought of it.想到这个，我忍不住轻轻地笑起来。

22 entirely   

ad.全部地，完整地；完全地，彻底地

参考例句：

• The fire was entirely caused by their neglect of duty. 那场火灾完全是由于他们失职而引起的。
• His life was entirely given up to the educational work. 他的一生统统献给了教育工作。

23 mechanism   

n.机械装置；机构，结构

参考例句：

• The bones and muscles are parts of the mechanism of the body.骨骼和肌肉是人体的组成部件。
• The mechanism of the machine is very complicated.这台机器的结构是非常复杂的。

24 volition   

n.意志；决意

参考例句：

• We like to think that everything we do and everything we think is a product of our volition.我们常常认为我们所做和所想的一切都出自自己的意愿。
• Makin said Mr Coombes had gone to the police of his own volition.梅金说库姆斯先生是主动去投案的。

25 overriding   

a.最主要的

参考例句：

• Development is of overriding importance. 发展是硬道理
• My overriding concern is to raise the standards of state education. 我最关心的是提高国民教育水平。

26 remains   

n.剩余物，残留物；遗体，遗迹

参考例句：

• He ate the remains of food hungrily.他狼吞虎咽地吃剩余的食物。
• The remains of the meal were fed to the dog.残羹剩饭喂狗了。

27 spoke   

n.（车轮的）辐条；轮辐；破坏某人的计划；阻挠某人的行动 v.讲，谈（speak的过去式）；说；演说；从某种观点来说

参考例句：

• They sourced the spoke nuts from our company.他们的轮辐螺帽是从我们公司获得的。
• The spokes of a wheel are the bars that connect the outer ring to the centre.辐条是轮子上连接外圈与中心的条棒。

28 arrogant   

adj.傲慢的，自大的

参考例句：

• You've got to get rid of your arrogant ways.你这骄傲劲儿得好好改改。
• People are waking up that he is arrogant.人们开始认识到他很傲慢。