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这篇短文来自扇贝阅读

Fingernails on a Chalkboard: Why This Sound Gives You the Shivers

指甲在黑板上滑动：为什么这种声音让你颤抖

Overall, research shows that this ear-splitting noise has the same frequency as that of a crying baby and a human scream, indicating that these sounds are tied to survival. For instance, people attuned to these frequencies may rescue a crying infant sooner, improving the baby's longevity.

一般来说，研究显示震耳欲聋的声音和有和孩子哭泣的声音和人类尖叫有同样的频率，表明这种声音和生存相关联。例如，人们认为这种频率可以更快的拯救一个哭泣的婴儿，提升孩子的寿命

One study has suggested that the shape of our ear canals, as well as our own perceptions, are to blame for our distaste of shrill sounds.

一种研究认为耳道的形状，就和我们的认知一样，是我们厌恶这种尖锐的声音的原因

The study's participants rated their discomfort to various unpleasant noises, such as a fork scraping against a plate or Styrofoam squeaking. The two sounds rated as the most unpleasant, they said, were fingernails scratching on a chalkboard and a piece of chalk running against slate.

研究的参与者将他们对大量不惹人喜欢的声音进行了评估，例如叉子刮盘子的声音、聚苯乙烯嘎吱的声响。其中两种声音被认为所最令人反感的，他们说，所指甲划过黑板的声音和粉笔划过岩石的声音。

The researchers then created variations of these two sounds by modifying certain frequency ranges, removing the harmonic portions. They told half of the listeners the true source of the sounds, and the other half that the sounds came from pieces of contemporary music.

研究人员制造出大量的这两种声音通过改变他们确定的评率范围，去除谐波分量。他们告诉一半的听者声音真正的源头，并且告诉另一半的人这个声音来自现代音乐的一段

Finally, they played back the new sounds for the participants, while monitoring certain indicators of stress, such as heart rate, blood pressure and the electrical conductivity of skin.

最终，他们给参与者回放新的声音，当检测某些压力指标，例如心率、血压和皮肤的电导率

They found that the offensive sounds changed the listeners' skin conductivity significantly, showing that they really do cause a measureable, physical stress reaction.

他们发现这个冒犯的声音极大的改变听者皮肤电导率，显示他们真的造成了可测量的物理的压力反应

The most painful frequencies were not the highest or lowest, but instead those that were between 2,000 and 4,000 Hertz. The human ear is most sensitive to sounds that fall in this frequency range, said study researcher Michael Oehler, a professor of media and music management at Macromedia University of Applied Sciences in Germany.

最让人难受的频率不是最高和最低的，而是那些在2000到4000赫兹之间的。人们的耳朵是对在这个频率内的声音是最敏感的，专业的在德国Macromedia 大学的应用科学影音管理人员研究人员Michael Oehler说道。

Oehler pointed out that the shape of the human ear canal may have evolved to amplify frequencies that are important for communication and survival. Thus, a painfully amplified chalkboard screech is just an unfortunate side effect of this development.

Oehler指出人耳道的形状可能已经进化得能够放大那些对交流和生存重要的频率。因此，痛苦的放大黑板刺响是这种进化的副作用

Brain pickings

大脑提取

Another study, published in the Journal of Neuroscience in 2012, reveals what's happening in the brain when people hear screechy sounds. The findings suggest that the fingernail-chalkboard sound triggers an uptick in communication between a region of the brain involved in hearing and another region of the brain involved in emotions.

另外一个研究，2012年的时候在Journal of Neuroscience 在公布，揭露了当人听到尖锐的声音大脑会发生的事情。研究认为指甲黑板声音触发了在大脑听力区域和大脑情感区域的交流的一个轻微的提升

In the study, 13 participants listened to 74 sounds, including nails on a chalkboard and the whine of power tools, and rated them according to their pleasantness. Researchers used functional magnetic resonance imaging (fMRI) to examine how the participants' brains responded to the sounds.

在研究中，13名参与者听了74个声音，包括指甲在黑板上和电动工具的哀鸣，并且测量了他们的不愉快程度。研究人员使用了核磁共振技术去测量参与者对于声音的大脑的反应

When the participants heard an unpleasant sound, there was an interaction between the auditory cortex, which processes sound, and the amygdala, which processes negative emotions.

当参与者听到这种不愉快的声音，听觉的大脑皮层（来处理这种声音）和杏仁体（会产生一个负面的情绪）就会发生作用

"It appears there is something very primitive kicking in," said study researcher Sukhbinder Kumar. "It's a possible distress signal from the amygdala to the auditory cortex."

“这显示了这是一种简单的作用”研究人员Sukhbinder Kumar说“这可能是杏仁体给听觉皮层的不幸的信号”

Moreover, the more averse the sound, the greater the activity between these two brain regions, the researchers said. Some of the most unpleasant sounds, according to the participants' ratings, included a knife on a bottle, a fork on a glass and chalk on a blackboard. The nicest sounds included flowing water, thunder and a laughing baby, they found.

而且，越多这种令人不快的声音，这两个大脑区域的活动就会更加的频繁，研究人员说。一些最让人不快的声音，根据参与者的测试，包括小刀在瓶上滑，叉子在玻璃上和粉笔在黑板上。最让人愉快的声音声音包括浇水、闪电和婴儿的笑声，他们发现

Frequencies between 2,000 and 5,000 Hertz were found to be unpleasant — roughly the same frequencies found by the 2011 research. "This is the frequency range where our ears are most sensitive," Kumar said. The reason for such sensitivity is not exactly understood, but this range includes the sounds of screams, which people find intrinsically unpleasant, he said.

频率在2000到5000赫兹的声音被发现是令人不快的—大致和2011年研究的评率相同“这种频率范围是我们耳朵最铭感的”Kumar 说。这种铭感的原因是位置的，但是这种范围包括尖叫的声音，本来就让人非常难受，他说

Ig Noble Prize

Ig诺贝尔奖

In a study investigating shrill sounds, scientists recorded the sound of a garden tool scraping over a chalkboard. Then the researchers fiddled with the recording, removing the high, middle and low frequencies from different recordings.

在一个调查尖锐声音的研究中，科学家记录园艺工具划过黑板的声音，然后研究人员处理录音，在不同的录音中去除高中低频在

After playing the modified sounds to volunteers, the researchers found that removing the high frequencies didn't make the sounds more pleasant. Rather, eliminating the low and middle frequencies of the sound made the sounds more appealing.

在给志愿者们播放了修改过的声音，研究人员发现去除了高频的声音并不能让人听起来更加舒服，相反去除了中低频让声音更加令人可以接受

In addition, the warning cry of a chimpanzee is similar to the sound of fingernails on a chalkboard, they found. Perhaps people have an unconscious reflex to this sound because of its uncanny resemblance to a warning call, the researchers told Medical Press.

此外，黑猩猩哭声的警告和指甲盖在黑板上的声音相似。他们发现或许人们有对这种声音无意识的反应，因为这种声音和警告的声音可怕的相似，研究人员告诉医学出版社