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At least once in your life, you've probably heard someone explain
一生中，你至少有一次听到过某人解释称
that if you start shaving somewhere new, the hair will grow back even thicker.
如果你开始刮掉某些区域新长出来的毛发，那么这块的毛发会越长越浓密。
And if you've ever rubbed your hand across rough stubble after a recent shave, you gotta understand why.
如果你摸摸刚被刮过的留茬，你会明白这种说法的。
But as far as scientists can tell, this is a thing even if our own experiences of battling body hair seem to say otherwise.
但是目前科学家们表示这完全是一种谬见，即便和体毛斗争的亲身经历似乎正好相反。
Scientists have been looking into the connection between shaving and hair thickness since at least 1928,
科学家们至少从1928年就开始观察剃毛和毛发厚度之间的联系，
when a study had four men repeatedly shave a certain part of their face.
当时一项研究要求四名男士反复给脸部某块区域剃毛。
That experiment, along with other early shaving studies, concluded that shaving didn't make people more hairy.
该实验以及其他早期相关研究的结论表明剃毛不会让毛发更浓密。
But they only measured the rate of hair growth, and not the thickness of the individual hair shafts.
但是它他们仅测量了毛发的生长率而没有测量个人毛干的厚度。
So, in a later study from 1970, researchers had 5 men shave one leg every week for several months.
所以，在1970年后的一项研究中，研究人员让五名男士在几个月内每周刮一条腿上的毛。
The other leg was left ungroomed, as the control.
作为对照，则不管另一条腿上的毛。
The team measured the diameter, density, and weight of the hair, as well as the rate of growth,
团队测量了毛发的直径、密度、重量以及生长率
and concluded that shaving didn't make the hair grow back thicker.
并得出结论—剃毛后不会让长回的毛发更浓密。
Other studies had similar results, like one from 2006 that analyzed high resolution photos taken with a microscope.
其他研究也得出了相似的结果，比如2006年的一项研究分析了用显微镜拍下的高分辨率照片。
Overall, studies consistently find that shaving doesn't make hair grow back faster or thicker, or make new hairs grow in the shaved area.
总的来说，研究一致发现剃毛不会让毛发生长更快或更厚实，也不会让被剃部分长出新毛发。
Still, the belief that shaving thickens hair is remarkably common.
剃毛会让毛发更浓密的说法仍然很常见。
Part of the reason might be that your first shaving experiences
部分原因可能是因为你的初次剃毛经历
often overlap with a dramatic period of hormonal fluctuation in your life.
通常和荷尔蒙波动的强烈期相重叠。
If you began shaving regularly around puberty, your hair probably was growing in thicker.
如果你在青春期开始定期剃毛，你的毛发可能越长越浓密。
But not because you were shaving!
但这不是剃毛引起的！
Another reason you might think the hair is thicker when it grows back is that over time,
另一个让你认为剃毛会让毛发越来越浓密的原因是随时间增长
hair gets lighter from exposure to things like sunlight or chemical compounds.
暴露在阳光或化合物中的毛发会越来越亮。
So the hair that grows back after a shave can look darker, but your cells aren't actually making hair with more pigment.
所以剃毛后长回来的毛发看起来更黑，但是你的细胞真的不会让毛发产生更多色素。
Shaving also creates a bit of an illusion around hair shaft thickness.
剃毛也会给毛干周围造成毛发浓密的假象。
When you shave, you're not like yanking the whole hair shaft out of its follicle — you're just slicing it off at the surface of your skin.
剃毛没有把毛囊中的整个毛干都拔出来—你只是把它们从皮肤表面刮掉。
It's like a blade of grass.
就像是一片草叶。
When you let it grow naturally, it tapers at the end and when you pass a lawnmower over it
当你让它自然生长时，它最后会长越细，但是当你用除草机时，
you chop it off near the base and leave a thick blunt end behind. The same thing happens with your hair.
根基附近的部分被除掉，留下的是厚厚的钝端。你的毛发也一样。
As it grows back after shaving it, it feels thicker and coarser because you've chopped it off at its thickest point,
感觉剃毛后长回来的毛发更厚更粗糙，这是因为你是在最浓密的点上将其剃除，
and lost the softer tapered end in the process.
在其过程中失去了更加柔软的锥形尾端。
But as the hair continues to grow, wear and tear will eventually taper off the blunt end again.
但是随着毛发的继续生长，磨损最终会再次逐渐削减出钝端。
So while you might feel some doubt as you closely examine your stubble in the mirror a couple of days after your last shave, rest assured:
所以当你在镜子前仔细检查自己的发茬时，你可能会感到怀疑，但是请放心：
You're not gonna create a thick carpet of hair through your grooming habits.
剃毛的习惯不会让你变成厚厚的小毛毯。
Otherwise, bald guys would shave their head every dang day.
否则秃顶的人每天都会剃头。
It's your body's natural growth cycle that's making this call for you!
是身体的自然生长周期让你变成这样的！
Thanks to Patreon patrons Allison and Gwendolyn B for asking,
感谢Patreon赞助人Allison和Gwendolyn B的提问，
and thanks to all of our patrons who suggest fascinating questions for us to answer!
感谢所有给我们提问求答案的赞助人！
If you want to help support this show and get access to our patrons-only quick questions inbox, you can check out patreon.com/scishow.
如果你想帮助支持我们并访问我们的赞助人专用问题接受箱，你可以登陆patreon.com/scishow。
