就像粽子是吃甜的还是咸的一样，网上时不时就会出现关于睡圆头好还是睡扁头好的讨论。
看看别人圆润饱满的头形，再摸摸自己小时候被睡扁的后脑勺，很难不发出这样的疑问：老一辈对睡扁头的执念到底是哪来的？
图源：新浪微博
我们所称的睡扁头，其实是头骨人工变形。
有调查研究显示，迄今为止人类颅骨人工变形最早的实物证据，距今约12000年。古人通过使用硬木板固定孩童头部的方式来实现颅骨重塑。
The skull named M45, the earliest known case of head modification on record, dates to about 12,000 years ago. Ancient people in China practiced human head-shaping by bounding some children’s maturing skulls, encouraging the heads to grow into elongated ovals.
吉林后套木嘎遗址发现迄今为止人类颅骨人工变形最早的实物证据，距今约12000年
在不少中国的文献古籍中，都可以看到与扁头有关的记载。
如《后汉书》中的“儿生欲令其头扁，皆押之以石”，意思是说如果想要孩子的后脑勺扁平，就要用石头来压住。
《满洲源流考》对睡扁头的方式也有着较为详细的记载：“国朝旧俗，儿生数月，置卧具，令儿仰寝其中，久而脑骨自平，头形似匾，厮乃习而自然，无足为异。”
不过，值得一提的是，让孩子平躺睡觉也是有科学依据的。
1992年，美国儿科协会曾发起“仰睡大行动”，鼓励幼儿采取平躺入眠，降低婴儿猝死综合征的风险。
During the early 90s, this condition arose with remarkable frequency due to the “back to sleep” campaign, which instructed parents to keep their babies on their backs to ward off SIDS.
如果长期仰卧，后脑变扁平的同时，脸庞也会变宽阔。传统面相讲究“天庭饱满、地阁方圆”，五官疏朗大方，是老一辈眼中的“福相”和“富贵相”，这也让符合这样特征的扁头深受老一辈喜爱。
如今，随着时代的发展，审美正发生改变。年轻人更加喜欢造型立体的五官和头部。有的人甚至开始为孩子佩戴头盔，从而达到“矫正”头形的目的。
Latest craze involves parents shelling out for helmets that they believe can help mold their babies' heads into ideal, rounded shapes. This is because perfectly round heads are viewed as the beauty standard nowadays.
世界各地的头骨执念
对于新生儿来讲，颅骨是柔软的，通过用手挤压婴儿头部，可以实现永久性的颅骨重塑。那么，国外是否也有颅骨重塑这一现象存在呢？
其实，世界上的不少地区都曾发掘出经过人工塑形的人类头骨。颅骨重塑跨越了不同的时代和地理位置。
Cranial deformation is believed to have existed for years and was common amongst certain groups of people. However, archaeologists do not believe that it originated from just one place.
世界各地头部形状独特的族群并不鲜见。
在古埃及的阿玛纳王朝时期，皇室成员都有着形状细长的头骨。不过，目前尚不清楚，这究竟是近亲结婚导致的，还是皇室成员独有的特征。
In Egypt, evidence of elongated skulls appears in all the members of the royal family in during the Armana epoch. Whether or not this was a genetic trait or one enforced on the royal members at birth is unknown.
图源：Ancient Wisdom
下面这座雕像是秘鲁钱凯文化的典型代表，类似的雕像在陵墓中随处可见，头部扁平且两分，标志着智慧、美丽。
图源：Body Arts
This figurine is typical of the Chancay civilization in the central coastal region of Peru, north of Lima, that prospered between AD 1200 and 1450. The exact significance of the flat, bi-lobed head is unclear but since such figures were often found in graves, it is likely to have represented a particular virtue such as wisdom, beauty or godliness.
北美原住民奇努克人还会采用特制的夹板，给新生儿的头颅塑形。
