研究告訴你人爲什麼會起雞皮疙瘩

Chilly bumps, goose pimples, goosebumps – there are a few names for when tiny elevations on your skin form that resemble a goose's flesh after its feathers are plucked.

冷風疹子、小疙瘩、雞皮疙瘩--有好幾個別名來形容這種情況。人的皮膚上有時候會起一些小疹子，看起來就像雞拔掉羽毛後的樣子。

And the cold, a sad tune or powerful scene from a movie can trigger this phenomenon when you least expect it.

人在遇到寒冷的時候，聽到悲傷的曲調的時候，或者從電影中看到令人震撼的場景的時候，就會產生這種你最不願看到的現象。

In this week's episode of BrainCraft, Youtuber Vanessa Hill dives into the weird and wonderful science of why humans experience the chilling sensation of goosebumps.

在本週的《大腦飛船》節目裏，凡妮莎·希爾在Youtube上展示了這一怪異而又奇妙的科學，解釋了爲什麼人會起雞皮疙瘩的疑問。

The scientific term for this evolutionary trait is pilomotor reflex or piloerection.

科學上描述這一進化特徵的專有名詞是“豎毛反射”或者“立毛”。

'I want you to think of the last time you remember experiencing them,' says Hill in the YouTube clip. 'Was it at the beginning of this video? And if not, was it from the cold? Or music? A movie? Were you just having an intense emotional response to something?'

希爾在Youtube視頻上說道：“我希望你們想一想最後一次起雞皮疙瘩的情形。那是不是在視頻開始的時候。如果不是，那麼因爲遇冷？音樂？或者電影？或者說你當時對什麼東西有強烈的情緒反應？”

She continues to explain when hair standing to attention, it forms a buffer between your skin and the cold air –helping you to thermorgulate or regulate your body temperature. This is why most people tend to get goosebumps when they are cold or feel a chill.

希爾繼續解釋說道，當毛髮豎起來的時候，在皮膚和冷空氣之間形成了一道屏障--從而幫助你調節溫度或者說控制體溫。那也正是爲什麼人在冷或者感覺冷的時候會起雞皮疙瘩。

The sensation is caused by the tiny muscles underneath each follicle, called arrector pili, and when they contract, the hair is pulled upright.

這種感覺是由每個毛囊裏的細小肌肉造成的，被稱之爲“立毛肌”，當這些肌肉收縮時，毛髮就會立起來。

'These are involuntary muscles and they're part of our sympathetic nervous system, which is responsible for most fight or flight responses,' explains Hill. 'The reaction is closely tied to our emotional state, and apart from being cold, this is why movies may be the best trigger for goosebumps.'

希爾解釋說道：“這些是'不隨意肌'，是我們交感神經系統的一部分，這個系統產生了大多數的應激反應。這個反應的產生和我們的情緒狀態有着密切的關係，這也正是爲什麼除了感覺冷以外，人們最經常因爲電影而起雞皮疙瘩。”

This is because brain imaging studies have found that goosebumps activates structures like the amygdala and parts of the prefrontal cortex -- both found associated with pleasure and reward. And there is no rhyme or reason to when this sensation will occur, as it is sometimes brought on by a distant memory of a past event.

關於大腦成像的研究已經發現，雞皮疙瘩能夠激活人類大腦中的杏仁核神經元和部分額葉皮質--這兩部分都和大腦的愉悅和激勵有關。而且雞皮疙瘩的產生沒有任何規律或者理由可尋，因爲有時人們會因爲記憶中久遠以前的一件事而起雞皮疙瘩。

However, this phenomenon is one which descends from our ancient ancestors who used it to keep warm and it may have even kept them alive by deterring predators -- but experts have deemed this reaction useless to modern day humans.

但是，這一現象是從我們的先祖那裏繼承而來的，他們曾利用這一反應來保持體溫。並且嚇跑捕食者--不過專家們認爲對於現代人類來說，這種反應毫無作用。

However, goosebumps are very important to some creatures of the world, such as cats, dogs and other mammals who use it has a way to seem larger and scarier to their predators.

然而，雞皮疙瘩對地球上其他一些生物來說卻非常重要，例如貓、狗和其他哺乳動物，它們用這一現象來使得自己看起來更大一些，從而嚇跑捕食者。