Why Do We Get Goosebumps?
为什么我们会起鸡皮疙瘩？
Imagine you're watching a scary movie and a masked man suddenly appears and kills the beautiful girl, scaring the hell out of you and giving you those infamous "goosebumps".
想象一下，你正在看一部恐怖电影，一个蒙面人突然出现，杀死了那个美丽的女孩，吓得你魂不附体，还让你起了些难看的“鸡皮疙瘩”。
To get over the scary film that you were just watching, you decide to go for a swim in a nearby lake.
为了忘掉刚才看的恐怖电影，你决定去附近的湖里游泳。
The water is quite warm, but there is a strong wind blowing, and the moment you step out of the water, you feel chilly and for the second time that night, you get goosebumps.
水很暖和，但是刮起了大风，当你走出水面的时候，你感到寒冷，这天晚上你又一次起了鸡皮疙瘩。
That same night, you're listening to some old music, and it brings back some fond memories.
还是同一天晚上，你在听一些老歌，它们勾起了你一些美好的回忆。
You begin to get all nostalgic（怀旧的） and emotional, and guess what! You get "goosebumps" yet again!
你开始变得怀旧和情绪化，你猜怎么着！你又起鸡皮疙瘩了！
So, why do these three unrelated events all seem to produce the same physical reaction in the body?
那么，为什么这三个不相关的事件似乎都能在体内产生相同的生理反应呢？
What are goosebumps and why do we get them?
什么是鸡皮疙瘩？又为什么会起鸡皮疙瘩呢？
Goosebumps are tiny elevations of the skin at the base of the hair, causing our skin to resemble（像） the skin of poultry（家禽） after the feathers have been plucked.
鸡皮疙瘩是毛发底部皮肤的微小隆起，导致我们的皮肤看起来像家禽拔毛后的皮肤。
The physical reaction of goosebumps have been passed to humans from our animal ancestors, who once had a lot more hair on their bodies.
起鸡皮疙瘩的生理反应是从我们的动物祖先那里传下来的，他们的身上曾经有很多毛发。
Goosebumps are caused when stress (cold temperature, perceived（感知到的） threat, intense emotions etc.) is experienced by our brain.
当我们的大脑感受到压力（寒冷的温度、感知到的威胁、强烈的情绪等）时，就会起鸡皮疙瘩。
In these moments, the nervous system sends a message to nerve endings that trigger the arrector（立肌） pili muscles, which cause goosebumps to appear.
在这些时刻，神经系统向神经末梢发送信息，触发竖毛肌，从而引起鸡皮疙瘩。
In animals with long hair, goosebumps help them protect against cold weather, as standing hair provides more insulation（隔离） to the body.
对于毛发长的动物来说，鸡皮疙瘩可以帮助它们抵御寒冷的天气，因为直立的毛发让身体更多地与外界隔离。
Also, a number of animals, including cats, use goosebumps to look larger and more intimidating when they feel threatened.
此外，包括猫在内的许多动物在感到威胁时会起鸡皮疙瘩，好让自己看起来更大更吓人。
In humans, goosebumps are a pretty useless feature, as we do not have much hair on our skin, but it can be a good indicator（指示） of our surroundings, whether we are too chilly, nervous, overextended, or emotionally drained!
对人类来说，鸡皮疙瘩是一个相当无用的特征，因为我们的皮肤上没有多少毛发，但它可以很好地指示我们周围的环境，无论我们是太冷、太紧张、过度伸展，还是情绪失控！