First, the relevant interpretation of ancient times:
Ancient thinkers and physicians in China not only realized that physical factors and physiological factors can lead to dreams, but also realized that psychological factors can lead to dreams. What psychological factors can cause people's dreams? Judging from the comments of ancient thinkers and physicians in China, perception, memory, thinking, emotion and personality will all affect the generation and content of dreams. But more discussion is about the influence of thinking, emotion and personality on dreams. (1) Thinking leads to dreams. (2) Emotion leads to dreams. (3) Personality leads to dreams.
Second, modern related explanations:
Dreams are a form of brain activity. It's almost like an idea. Unlike other organs, the brain supports rest or doesn't need much rest. When most organs of the human body stop working, only a few organs continue to work, such as the brain. In fact, in normal times, our brains also have dreams. It's just that this dream is not another dream. Every day when we are awake, the brain processes the information we receive from the outside world, and our limbs and other parts can respond to the information from the outside world. (logical operation, instinctive reaction, etc. ) But at night, it's different. We are sleeping, and the brain is still processing external information. The difference is that we are sleeping. Therefore, in many cases, its processing results will not cause reactions of limbs and so on, but the results still exist, so they exist in our minds (including the subconscious). It formed a dream.
Think during the day and dream at night. In the same way, the brain will deal with things that we often associate with, and at night, the brain will also deal with them habitually.