How to Boost Your Memory? Try Sleeping on It

 How to Boost Your Memory? Try Sleeping on It

Can't remember where you put your keys? Here's a tip for you: record the sound of your jingling¹ keys and put it into your iPod. Then get someone to play it to you at night, while you are deep asleep. Chances are it'll help you remember.

That's the conclusion of a recent report in the journal Science by neuroscientists at Northwestern University, who carried out a small study, with 12 volunteers, to figure out whether specific sounds played during sleep would boost the memory of information learned while awake.

First, the participants were asked to memorize the correct location of 50 images on a computer monitor. The images were shown one at a time, arranged in a random² place on the screen — a cat appeared on the bottom left, a gong on the top right and so forth³. Each object was shown with a related sound — so subjects heard a meow with the picture of a cat, and a crashing noise coupled with the image of a gong. After studying the 50 images and locations, the participants were asked to take a short nap in a recliner in an adjacent room.

Volunteers for the study weren't hard to find, notes Ken⁴ Paller, professor of psychology⁵ at Northwestern University and lead author of the paper: "People are happy when they are paid to have a nap."

The volunteers were outfitted⁶ with electrode caps — akin⁷ to a white shower cap with a jungle of wires sticking out of it — that tracked their brain waves in order to determine their stage of slumber⁸. Using an electroencephalogram (EEG), investigators⁹ monitored the sleepers¹⁰' brain activity, and just when the squiggly lines on the screen showed that participants had entered deep sleep, researchers began playing a series of 25 of the sounds that the individual had heard earlier in the memory game. "[The volume] was a little over a whisper, probably much [quieter] than ... your iPod," says John Rudoy, one of the study's authors and a graduate student at Northwestern. (See the top 10 medical breakthroughs of 2008.)

When the participants woke up about an hour later, they said they hadn't heard a thing. But the test results suggested otherwise. On average, each person did slightly better at remembering the correct locations of the 25 objects whose related sounds had been cued during sleep than those of the other objects. The sounds appeared to have entered the sleeping brain and helped consolidate¹¹ associated memories.

Many researchers who study sleep and memory were excited by this new study (not to mention purveyors of nighttime subliminal-message CDs that purport¹² to make you quit smoking or love yourself) — but experts acknowledge that more work needs to be done. "I would consider this a very, very small effect," says Paller, so don't expect to be able to boost your SAT score while sleeping just yet.

For nearly two centuries, researchers have suspected that sleep plays an important role in learning and memory. But it's only in the last decade that neuroscientists have discovered the most convincing evidence that memory is indeed dependent on sleep. The prevailing¹³ theory is that during deep sleep, the brain replays certain experiences from the day, which, in turn, strengthens the memory of what happened. It is thought that when it comes to factual memories, like names, faces, numbers or locations, memory consolidation¹⁴ happens only during deep sleep — a phase of non–rapid eye movement sleep. (The other broad type of sleep, called rapid eye movement or REM sleep, which is when dreaming occurs, is believed to play a role in consolidating¹⁵ memories involving emotions and motor skills, such as dancing or playing an instrument.)

A minority of neuroscientists disagree that sleep actively¹⁶ aids memory, suggesting instead that consolidation of memories is merely a side effect of snoozing. They argue that the true purpose of sleep is to "cool down" the brain by resting the neurons that have been firing all day long. Paller's study lends support for the majority view: when sounds were played to the sleeping brain, the EEG patterns indicated activity — signaling that perhaps certain memories were being revisited — and this processing appeared to strengthen memories. "The meow somehow stimulated¹⁷ the association of the cat with a certain position on the screen," suggests Jan Born, a memory and sleep researcher at the University of Lübeck in Germany, who was not involved in the new study.

Born and his team have also been able to influence memory recall during sleep — not with sounds, but with odors. In that study, published in March 2007 in Science, researchers asked people to play a memory card game while the smell of roses wafted¹⁸ through a special face mask. Later that night, when the participants were fast asleep, the same odor was delivered to some of them. The following morning, each person played the same game, and the results were clear: the players who got the nighttime rose odor were significantly better at remembering the card pairs than the group who smelled nothing.

Commenting on the new paper, Born suggests that using sounds is more effective than smells because it lets you choose the memories you want to promote. "Auditory stimuli¹⁹ have the advantage that they can be very specifically linked to visual stimuli," says Born. "With odors, this kind of thing is not possible."

Beyond sensory²⁰ stimulation²¹ during sleep, the timing²² of sleep may also be important to memory. Recent research suggests that deep sleep can strengthen factual memories, but only if the person naps within 12 hours of learning. In other words, if you have to memorize an SAT word list, you might be better off doing it at night rather than in the morning.

Although researchers are still a long way from understanding exactly how sleep affects memory, they are certain that getting too little sleep is a detriment²³. A 2007 paper in Nature Neuroscience reported that in addition to consolidating recently learned memories, "sleep before learning is equally important in preparing the brain for next-day memory formation." The study found that people who had skipped a night's sleep fared worse at making new memories the next day, compared with those who had gotten a good night's sleep. Turns out, Mom's advice may have been right all along.

1 jingling   

叮当声

参考例句：

• A carriage went jingling by with some reclining figure in it. 一辆马车叮当驶过，车上斜倚着一个人。 来自英汉文学 - 嘉莉妹妹
• Melanie did not seem to know, or care, that life was riding by with jingling spurs. 媚兰好像并不知道，或者不关心，生活正马刺丁当地一路驶过去了呢。

2 random   

adj.随机的；任意的；n.偶然的(或随便的)行动

参考例句：

• The list is arranged in a random order.名单排列不分先后。
• On random inspection the meat was found to be bad.经抽查，发现肉变质了。

3 forth   

adv.向前；向外，往外

参考例句：

• The wind moved the trees gently back and forth.风吹得树轻轻地来回摇晃。
• He gave forth a series of works in rapid succession.他很快连续发表了一系列的作品。

4 ken   

n.视野，知识领域

参考例句：

• Such things are beyond my ken.我可不懂这些事。
• Abstract words are beyond the ken of children.抽象的言辞超出小孩所理解的范围.

5 psychology   

n.心理，心理学，心理状态

参考例句：

• She has a background in child psychology.她受过儿童心理学的教育。
• He studied philosophy and psychology at Cambridge.他在剑桥大学学习哲学和心理学。

6 outfitted   

v.装备，配置设备，供给服装( outfit的过去式和过去分词 )

参考例句：

• They outfitted for the long journey. 他们为远途旅行准备装束。 来自《现代英汉综合大词典》
• They outfitted him with artificial legs. 他们为他安了假腿。 来自辞典例句

7 akin   

adj.同族的，类似的

参考例句：

• She painted flowers and birds pictures akin to those of earlier feminine painters.她画一些同早期女画家类似的花鸟画。
• Listening to his life story is akin to reading a good adventure novel.听他的人生故事犹如阅读一本精彩的冒险小说。

8 slumber   

n.睡眠，沉睡状态

参考例句：

• All the people in the hotels were wrapped in deep slumber.住在各旅馆里的人都已进入梦乡。
• Don't wake him from his slumber because he needs the rest.不要把他从睡眠中唤醒，因为他需要休息。

9 investigators   

n.调查者，审查者( investigator的名词复数 )

参考例句：

• This memo could be the smoking gun that investigators have been looking for. 这份备忘录可能是调查人员一直在寻找的证据。
• The team consisted of six investigators and two secretaries. 这个团队由六个调查人员和两个秘书组成。 来自《简明英汉词典》

10 sleepers   

n.卧铺（通常以复数形式出现）；卧车( sleeper的名词复数 )；轨枕；睡觉（呈某种状态）的人；小耳环

参考例句：

• He trod quietly so as not to disturb the sleepers. 他轻移脚步，以免吵醒睡着的人。 来自辞典例句
• The nurse was out, and we two sleepers were alone. 保姆出去了，只剩下我们两个瞌睡虫。 来自辞典例句

11 consolidate   

v.使加固，使加强；(把...)联为一体，合并

参考例句：

• The two banks will consolidate in July next year. 这两家银行明年7月将合并。
• The government hoped to consolidate ten states to form three new ones.政府希望把十个州合并成三个新的州。

12 purport   

n.意义，要旨，大要；v.意味著，做为...要旨，要领是...

参考例句：

• Many theories purport to explain growth in terms of a single cause.许多理论都标榜以单一的原因解释生长。
• Her letter may purport her forthcoming arrival.她的来信可能意味着她快要到了。

13 prevailing   

adj.盛行的；占优势的；主要的

参考例句：

• She wears a fashionable hair style prevailing in the city.她的发型是这个城市流行的款式。
• This reflects attitudes and values prevailing in society.这反映了社会上盛行的态度和价值观。

14 consolidation   

n.合并,巩固

参考例句：

• The denser population necessitates closer consolidation both for internal and external action. 住得日益稠密的居民，对内和对外都不得不更紧密地团结起来。 来自英汉非文学 - 家庭、私有制和国家的起源
• The state ensures the consolidation and growth of the state economy. 国家保障国营经济的巩固和发展。 来自汉英非文学 - 中国宪法

15 consolidating   

v.（使）巩固， （使）加强( consolidate的现在分词 )；（使）合并

参考例句：

• These measures are meant for consolidating the system of basic medical care. 这些举措旨在夯实基层医疗体系，让老百姓看大病不必出远门。 来自互联网
• We are consolidating the Chinese and English versions of our homepage. 我们将为您提供中英文版本一起的主页。 来自互联网

16 actively   

adv.积极地，勤奋地

参考例句：

• During this period all the students were actively participating.在这节课中所有的学生都积极参加。
• We are actively intervening to settle a quarrel.我们正在积极调解争执。

17 stimulated   

a.刺激的

参考例句：

• The exhibition has stimulated interest in her work. 展览增进了人们对她作品的兴趣。
• The award has stimulated her into working still harder. 奖金促使她更加努力地工作。

18 wafted   

v.吹送，飘送，（使）浮动( waft的过去式和过去分词 )

参考例句：

• The sound of their voices wafted across the lake. 他们的声音飘过湖面传到了另一边。
• A delicious smell of freshly baked bread wafted across the garden. 花园中飘过一股刚出炉面包的香味。 来自《简明英汉词典》

19 stimuli   

n.刺激（物）

参考例句：

• It is necessary to curtail or alter normally coexisting stimuli.必需消除或改变正常时并存的刺激。
• My sweat glands also respond to emotional stimuli.我的汗腺对情绪刺激也能产生反应。

20 sensory   

adj.知觉的，感觉的，知觉器官的

参考例句：

• Human powers of sensory discrimination are limited.人类感官分辨能力有限。
• The sensory system may undergo long-term adaptation in alien environments.感觉系统对陌生的环境可能经过长时期才能适应。

21 stimulation   

n.刺激，激励，鼓舞

参考例句：

• The playgroup provides plenty of stimulation for the children.幼儿游戏组给孩子很多启发。
• You don't get any intellectual stimulation in this job.你不能从这份工作中获得任何智力启发。

22 timing   

n.时间安排，时间选择

参考例句：

• The timing of the meeting is not convenient.会议的时间安排不合适。
• The timing of our statement is very opportune.我们发表声明选择的时机很恰当。

23 detriment   

n.损害；损害物，造成损害的根源

参考例句：

• Smoking is a detriment to one's health.吸烟危害健康。
• His lack of education is a serious detriment to his career.他的未受教育对他的事业是一种严重的妨碍。