Most of us can't bear the sound of nails on a chalkboard , but now, researchers have a possible explanation as to why the sound makes us cringe and cover our ears.
我們大部分人都忍受不了用指甲刮黑板的聲音，現(xiàn)在科學家們對我們無法忍受這種聲音并忍不住要捂耳朵的現(xiàn)象有了一種解釋。

It turns out our adverse reaction to the piercing sound is partly physical and partly psychological, and that the part of the noise that makes us wince has a frequency between 2,000 and 4,000 Hz (hertz), a range naturally amplified by the shape of our ear canals, Wired Science explains.
我們對刺耳的聲音做出的不良反應(yīng)一部分是生理的，一部分是心理的。這種讓我們難受的聲音一般是在2000-4000赫茲之間，由于我們耳廓的形狀，這個區(qū)間內(nèi)的聲音會被放大，Wired Science解釋說。

Researchers from the Macromedia University for Media and Communication in Germany and the University of Vienna worked together to get to the bottom of the sound's bad rep.
來自德國Macromedia傳媒學院和維也納大學的研究者一起研究出了出現(xiàn)這種情況的原因。

They exposed participants to the sound of nails on a chalkboard as well as similar sounds, such as a fork scraping a plate and Styrofoam squeak, according to ScienceNow.
ScienceNow刊文顯示，科學家們揭示了測試參加者無法忍受類似于指甲刮黑板、叉子刮盤子和塑料摩擦的聲音的原因。

Some were told the sound was part of a "musical composition," while others were told the source of the noise. The researchers measured the physical reactions (blood pressure, heart rate, skin conductivity) of all persons. All participants were told to rate how pleasant or unpleasant they found each noise to be.
科學家們告訴一部分受測試者，說這是某個“樂曲”的一部分，而告訴另一部分受測試者，說這是噪音。通過測量受測試者的身體反應(yīng)（包括血壓、心率、皮膚傳導性），來得知受測試者對這段音樂的反應(yīng)。

Researchers also experimented with removing certain parts of the sound in an effort to identify which parts participants found unpleasant.
研究者試著移除整段聲音的某些段落，試圖找出是哪一段讓人有不舒服的感覺。

If people knew what caused the noise, they tended to rate it as more unpleasant. Those who were told the noise was part of a tune rated it as less unpleasant. However, both groups had measurable physical reactions to the displeasing frequencies, despite how they rated the sound, Wired Science points out.
如果人們知道造成這種噪聲的是什么，覺得難受的幾率會增加。而被告知這是樂音的人，覺得難以忍受的幾率則會較低。Wired Science指出，不論他們怎么看待這段聲音，兩組受測試者對這種讓人難受的音頻頻率都表現(xiàn)出了一定的身體反應(yīng)。