VOA健康报道2024--What Is the Color of Noise? Can It Help Sleep, Memory?

What Is the Color of Noise? Can It Help Sleep, Memory?

From VOA Learning English, this is the Health & Lifestyle report.

You may have heard of white noise being used to cover or hide background sounds. But now white noise has some colorful competition.

There is a growing interest around different kinds of noises. Pink noise, brown noise, and green noise make up a rainbow of calming sounds. And there is a growing interest in their theoretical effects on sleep, concentration, and relaxation¹.

The science is new. There have only been a few small studies that look at the effects of the noises. But the lack of research has not stopped thousands of people from listening to hours of these noises on YouTube and on meditation² apps.

What is pink noise?

Before we look at pink noise, let’s talk about the most common of colored noises -- white.

White noise is similar to static on a radio or television. Sound engineers describe it as having equal volume across all the frequencies that humans can hear. It gets its name from white light, which contains all the visible color wavelengths⁴.

However, the high frequencies of white noise can sound severe. Pink noise reduces the sound on those higher frequencies. It sounds lower in pitch, more like the natural sound of rain or the ocean.

Let’s listen to an example of white noise.

[AUDIO EXAMPLE: WHITE NOISE]

And this is an example of pink noise.

[AUDIO EXAMPLE: PINK NOISE]

Brown noise is even lower in pitch. This makes a pleasing sound.

[AUDIO EXAMPLE: BROWN NOISE]

Pink and brown have standard definitions to audio experts. Other colored noises, such as green, are more recent creations. So, their definitions are not as strict.

How are colored noises used to help?

Some research has found that white noise and pink noise may provide help for people with attention-deficit/hyperactivity disorder⁵, or ADHD. These people have difficulty staying on a task or finishing it. This claim comes from a review of limited ADHD studies.

In theory, white and pink noises wake up the brain, said ADHD researcher Joel Nigg. He is with Oregon Health & Science University in Portland.

He is a co-writer of the report “Systematic Review and Meta-Analysis: Do White Noise or Pink Noise Help With Task Performance in Youth With Attention-Deficit/Hyperactivity Disorder or With Elevated Attention Problems?” It appeared in the Journal of the American Academy of Child & Adolescent Psychiatry⁶.

“The noise provides stimulation⁷ to the brain without providing information, and so it doesn’t distract,” Nigg said.

White noise has been used to treat ringing or buzzing in the ear, called tinnitus.

Scientists at Northwestern University in Illinois are studying how short pulses of pink noise can increase the slow brain waves of deep sleep. In small studies, these pink-noise pulses have shown promise in improving memory and the relaxation response.

Dr. Roneil Malkani is a professor of brain science at Northwestern University’s Feinberg School of Medicine. He said the frequency characteristics of pink noise are similar to “…brain wave frequencies we see in slow-wave sleep because these are large, slow waves.”

If the research on pink noise at Northwestern University holds up under testing, it could lead to a medical device aimed at improving sleep or memory through pulses of pink noise. These pulses would be made to fit an individual.

But many scientific questions remain unanswered, Malkani said. “There’s still a lot of work we have to do.”

Is there any harm in trying colored noises?

If colored noises feel calming and help you focus, it makes sense to use them. But Nigg offers a few pieces of advice. He suggests keeping them at a quiet level to prevent hearing loss and to take “plenty of breaks for the ears to rest.”

Words in This Story

static -n. noise produced in a radio or television receiver by atmospheric⁸ or electrical disturbances⁹ frequency -n.

wavelength³ -n. the distance (as from crest¹⁰ to crest) in the line of advance of a wave from any one point to the next corresponding point

pitch -n. the property of a sound and especially a musical tone that is determined¹¹ by the frequency of the waves producing it : highness or lowness of sound

stimulate¹² -v. to excite to activity or growth or to greater activity : stimulation -n.

distract -v. to draw the attention or mind to something else

pulse -n. an electromagnetic wave or a sound wave lasting only a short length of time

1 relaxation   

n.松弛，放松；休息；消遣；娱乐

参考例句：

• The minister has consistently opposed any relaxation in the law.部长一向反对法律上的任何放宽。
• She listens to classical music for relaxation.她听古典音乐放松。

2 meditation   

n.熟虑，（尤指宗教的）默想，沉思，（pl.）冥想录

参考例句：

• This peaceful garden lends itself to meditation.这个恬静的花园适于冥想。
• I'm sorry to interrupt your meditation.很抱歉，我打断了你的沉思。

3 wavelength   

n.波长

参考例句：

• The authorities were unable to jam this wavelength.当局无法干扰这一波长。
• Radio One has broadcast on this wavelength for years.广播1台已经用这个波长广播多年了。

4 wavelengths   

n.波长( wavelength的名词复数 )；具有相同的/不同的思路；合拍；不合拍

参考例句：

• I find him difficult to talk to—we're on completely different wavelengths. 我没法和他谈话，因为我们俩完全不对路。 来自《简明英汉词典》
• Sunlight consists of different wavelengths of radiation. 阳光由几种不同波长的射线组成。 来自辞典例句

5 disorder   

n.紊乱，混乱；骚动，骚乱；疾病，失调

参考例句：

• When returning back,he discovered the room to be in disorder.回家后，他发现屋子里乱七八糟。
• It contained a vast number of letters in great disorder.里面七零八落地装着许多信件。

6 psychiatry   

n.精神病学，精神病疗法

参考例句：

• The study appeared in the Amercian science Journal of Psychiatry.这个研究发表在美国精神病学的杂志上。
• A physician is someone who specializes in psychiatry.精神病专家是专门从事精神病治疗的人。

7 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。

8 atmospheric   

adj.大气的，空气的；大气层的；大气所引起的

参考例句：

• Sea surface temperatures and atmospheric circulation are strongly coupled.海洋表面温度与大气环流是密切相关的。
• Clouds return radiant energy to the surface primarily via the atmospheric window.云主要通过大气窗区向地表辐射能量。

9 disturbances   

n.骚乱( disturbance的名词复数 )；打扰；困扰；障碍

参考例句：

• The government has set up a commission of inquiry into the disturbances at the prison. 政府成立了一个委员会来调查监狱骚乱事件。
• Extra police were called in to quell the disturbances. 已调集了增援警力来平定骚乱。

10 crest   

n.顶点；饰章；羽冠；vt.达到顶点；vi.形成浪尖

参考例句：

• The rooster bristled his crest.公鸡竖起了鸡冠。
• He reached the crest of the hill before dawn.他于黎明前到达山顶。

11 determined   

adj.坚定的；有决心的

参考例句：

• I have determined on going to Tibet after graduation.我已决定毕业后去西藏。
• He determined to view the rooms behind the office.他决定查看一下办公室后面的房间。

12 stimulate   

vt.刺激，使兴奋；激励，使…振奋

参考例句：

• Your encouragement will stimulate me to further efforts.你的鼓励会激发我进一步努力。
• Success will stimulate the people for fresh efforts.成功能鼓舞人们去作新的努力。