In the third millenium BCE, Mesopotamian kings recorded and interpreted their dreams on wax tablets.
公元前三千年，美索不达米亚国王在蜡质石板上记录并解释了他们的梦。
A thousand years later, Ancient Egyptians wrote a dream book listing over a hundred common dreams and their meanings.
一千年之后，古埃及人写了一本关于梦的书，列出了一百多个日常的梦以及它们的解释。
And in the years since, we haven't paused in our quest to understand why we dream.
多年之后，我们从未停止过探索我们做梦的原因。
So, after a great deal of scientific research, technological advancement, and persistence, we still don't have any definite answers, but we have some interesting theories.
所以，我们在经历了大量的科学研究、科技进步以及坚持不懈之后，依旧没有任何确切的答案，但是我们已经发展了一些有趣的理论。
We dream to fulfill our wishes.
我们为了满足自己的愿望而做梦。
In the early 1900s, Sigmund Freud proposed that while all of our dreams, including our nightmares, are a collection of images from our daily conscious lives, they also have symbolic meanings, which relate to the fulfillment of our subconscious wishes.
在19世纪早期，西格蒙德·弗洛伊德提出，虽然我们所有的梦包括梦魇，都来自有意识的日常生活画面集，但他们也有一些抽象意义，它和我们潜意识中的愿望满足感有关。
Freud theorized that everything we remember when we wake up from a dream is a symbolic representation of our unconscious primitive thoughts, urges, and desires.
弗洛伊德提出，我们从梦中醒来记得的所有事情都是无意识的原始想法、冲动、以及欲望的象征性代表。
Freud believed that by analyzing those remembered elements, the unconscious content would be revealed to our conscious mind, and psychological issues stemming from its repression could be addressed and resolved.
弗洛伊德相信，通过分析我们记得的这些元素，那些无意识的内容可以反映出我们有意识的思想，精神上受到的压抑可以被理解和解答。
We dream to remember.
我们做梦是为了记忆。
To increase performance on certain mental tasks, sleep is good, but dreaming while sleeping is better.
为了加强一些脑力工作上的表现，睡眠非常有效，然而睡觉时做梦效果会更好。
In 2010, researchers found that subjects were much better at getting through a complex 3-D maze if they had napped and dreamed of the maze prior to their second attempt.
2010年，研究人员发现，如果被试者在第二次尝试穿越迷宫之前小憩一会儿并且做了一会儿梦的话，他们在穿越一个复杂的三维迷宫时会表现更佳。
In fact, they were up to ten times better at it than those who only thought of the maze while awake between attempts, and those who napped but did not dream about the maze.
事实上，他们比那些在两次之间醒着思考迷宫的人，以及那些虽然睡了但是没有做梦的人表现要好十多倍。
Researchers theorize that certain memory processes can happen only when we are asleep, and our dreams are a signal that these processes are taking place.
研究者推断，特定的记忆过程只在我们睡着时才会发生，而我们的梦是一个触发这些过程的信号。
We dream to forget.
我们做梦是为了遗忘。
There are about 10,000 trillion neural connections within the architecture of your brain.
我们的大脑构造里有大约一万兆的神经连接。
They are created by everything you think and everything you do.
它们因你思考以及所做的所有事情而形成。
A 1983 neurobiological theory of dreaming, called reverse learning, holds that while sleeping, and mainly during REM sleep cycles, your neocortex reviews these neural connections and dumps the unnecessary ones.
1983年，一个关于梦的神经生物学理论提出逆向学习的概念，该理论认为我们在睡觉时，尤其是在快速眼动睡眠周期时，大脑新皮质会回顾这些神经连接并清理掉那些不需要的部分。
Without this unlearning process, which results in your dreams, your brain could be overrun by useless connections and parasitic thoughts could disrupt the necessary thinking you need to do while you're awake.
如果没有做梦来产生这种反学习的过程，你的大脑就会因无用连接而过度运转，同时无用的想法会干扰到你醒着的时候需要进行的必要思考。
