It is really a ghost.

There is a popular saying in China that ghosts press the bed. Ghosts in people's mouths look different, but the experience of encountering ghosts is very similar. What are these terrible monsters that are ready to act in the middle of the night? Why do they make waves in our sweet sleep and make people restless? An expedition to find ghosts began. How much does the ghost know in the dream? "Things always happen when I just fall asleep or just get up. That strange and horrible experience is very clear. I'm sure I'm awake I have woken up from my sleep, but I also clearly know that something unusual is hovering around me. " "I can hear someone whispering my name in my ear. He turned on the lamp and leaned over me. I can even clearly see the shadow of this person reflected on the wall. " "My ears rumbled and my whole body trembled like an electric shock. A terrible black monster sat on my chest. He made me unable to breathe and my chest was extremely heavy. My consciousness is very clear. I want to scream and punch him away, but no matter how hard I try, my body can't move and I don't listen to my command at all. I'm scared. " Listen to these remarks! There is a terrible ghost in your bedroom. He will threaten you like a prank, but you can't move. I can only watch him run amok. People who meet ghosts are usually sober. They know that they are not making up some unrealistic stories. They really felt the hidden danger around them. The TV set at home is turned on, and the dialogue of the characters in the TV can be clearly heard. The electric fan beside the bed started, and a white shadow stood in front of it, shaking back and forth by the wind. This is a terrible thing for anyone. The footprints of ghosts seem to have traveled everywhere where people live. In18th century England, people were afraid of a monster called nightmare demon, which would invade women while they were asleep and make them unable to move. In Germany, a similar experience is called "witch crossing", in Thailand it is called "being hugged by ghosts" and in Japan it is widely accepted to be "bound by metal". In Newfoundland, Canada, similar demons are called "old witches". He appeared in the form of terror, sitting on the chest of a sleeping man. In Zanzibar, Tanzania, the islanders dictated a magical flying dwarf-"Bob Bawa". The above description has obvious traces of regional culture, but some features are very consistent. These ghosts haunt people when they sleep. They can restrain people's actions and make people feel extremely scared. It's not fun to let these monsters break into our home and control our bodies between dreams and waking up. We must catch these reckless guys! Since these ghosts always appear after people fall asleep, let's lurk next to the sleeping people and see if the ghosts dare to provoke them. Through the observation of sleepers, scientists found that people always do periodic eye movements regularly during sleep. This aroused the interest of researchers, who recorded the whole EEG activity during sleep with instruments and divided the sleep process into several stages according to the types of brain waves. The first stage is called slow-wave sleep. According to the sleep EEG, as the sleep goes from shallow to deep, the amplitude of the pattern goes from low to high, and the frequency goes from fast to slow, and normal sleep begins at this stage. According to the characteristics of brain waves, scientists divide this stage into four stages: thinking sleep, light sleep, middle sleep and deep sleep. The process of slow wave sleep is from the first stage to the fourth stage, and then from the fourth stage to the first stage. After the first stage, sleep turns to the fast wave stage. This period is also called heterogeneous sleep, because the sleep is deep at this time, but the EEG activity is similar to that of awakening. With the help of the instrument, scientists can observe that the sleeper's breathing becomes shallow and fast, the heart rate increases, the blood pressure increases, and the cerebral blood flow doubles, especially when the eyes often move suddenly and rapidly, so this stage is also called rapid eye movement sleep. At this stage, people are most sensitive to external stimuli and are easily awakened. After rapid eye movement sleep, it circulates to shallow sleep, and the whole process lasts about 90 minutes. This cycle usually goes through 4~6 times a night. At this point, the scientists stayed the whole night and found no trace of ghosts. Did these scary guys get the news of being rounded up in advance and temporarily hide? Scientists decided to make persistent efforts. They wake the subject once in each sleep stage and ask him what he is thinking. In the slow-wave sleep stage, the subjects claimed that they would have some short-lived thoughts during sleep, but most of them were not dreams full of imagination, magnificent colors and specific contents. Only in the rapid eye movement stage, 80% of the subjects reported that they were dreaming, and most people's dreams did not enter the memory. The dream they remember is usually the last dream they had before they woke up. The researchers further found that during REM sleep, there will be a mechanism in the human body, and the brain stem area will send out special information, which will inhibit the function of the brain motor center and lead to physical paralysis. This paralysis is meaningful because it can prevent our limbs from moving in dreams, thus preventing our bodies from being hurt during sleep. Similar experiences are also shown in animal experiments. Scientists cut off the neural pathways that inhibit the muscles of animals' brains. When animals go to REM sleep, their muscles are not inhibited, and they will show what they do in their dreams. For example, a sleeping cat, because its muscles are not restrained, usually makes patrol behavior, which often appears in cats' dreams. Scientists have a hunch that they are getting closer to the truth step by step, and this paralyzed state is familiar. I remember that in the previous survey, everyone who was harassed by ghosts described themselves as unable to move, which is so similar to the fact that the brain suppressed the motor center and almost paralyzed all muscles. The difference is that people who are paralyzed are usually in sweet sleep, while people who are haunted by ghosts claim that they are completely awake and really see people. Hallucinations and ghosts come to dreams. Generally speaking, this paralysis will subside after we wake up, but for some people, it doesn't always happen as expected. These people often suffer from REM sleep. Harassment usually occurs when people are half asleep, and the awakening system in the brain is easily stimulated. Under the action of fast-frequency brain waves similar to waking state, people will have "false awakening", that is, when they wake up, they find themselves still dreaming and sleeping in reality. This "false wake-up" is usually repeated many times, accompanied by fear of this repetition. When the sleep state extends to the awake state, it will produce extremely realistic hallucinations, which are much clearer than our memories of ordinary dreams. Because at this time, our brain is awake, the dream in our brain continues, and the conscious mind constantly reflects the situation in the dream. For these illogical fantasy scenes, we instinctively associate them with potential threats, generate fear and expect to protect ourselves. Unfortunately, at such a critical moment, the inhibition has not been lifted. The skeletal muscles of the whole body are still in a state of bondage except the respiratory muscles and eye muscles, and we can't control our bodies. In the face of this "lucid dream", we are extremely frightened, and even if we struggle to wake up, we are already sweating. Fortunately, this paralysis only lasted for a few seconds to a few minutes, and then we were free again, and the terrible ghost disappeared without a trace. Now scientists finally know what these different ghosts are. These fearful and evil people who originally lived in people's imaginary world took the opportunity to invade people's awake brains when they experienced REM sleep disorder. This phenomenon is called sleep paralysis. 60% people will experience sleep paralysis once in their lives, but some people are often troubled by it. These people usually have a family history, and their awakening system has extraordinary vigilance. Weird "alien" psychologists believe that the concept of sleep paralysis can also explain other incomprehensible anomalies. The researchers found that most people who claimed to be kidnapped by aliens had this experience: "I woke up in the middle of the night and found that my body could not move. I felt as if there was something in the room, and that was aliens." According to statistics, about 1000 people claim to have seen aliens. By analyzing their personalities, it is found that most people are convinced of divination, constellations and the like, and they love fantasy. But obviously, they all have symptoms of sleep paralysis. Not only aliens, but also angels, demons and vampires appear in their consciousness. It turns out that many aliens are just sleeping with people as a joke, which is an illusion created by people themselves. However, why do so many people want to believe that they have been kidnapped and violated by aliens? Scientists have found that in experiments, those who are "kidnapped" are more inclined to express false memories and cognition, and they often describe more details when talking to experts. This way of helping memory through imagination afterwards is bound to produce false memories more easily. Psychologists conducted a standard word association test on people who claimed to have been kidnapped by aliens to understand the extent of their false memories. Participants should infer a word that is not given according to the relationship between the given words, for example, from "sugar", "candy", "acid" and "bitterness", infer that the word that is not given is "sweet". In this test, people who have memories of being kidnapped by aliens are more likely to give wrong answers. They often mistakenly attribute the source of memory to, for example, confusing the vague memory of a movie with a dream. In another experiment, the researchers found that recalling the memory of kidnapping can cause some physiological changes in the body, for example, blood pressure and sweat gland reaction fluctuate greatly. Those memories caused strong mental trauma. Whenever this kind of memory appears, it will deepen people's impression that illusion is really a reality. On the other hand, it may be thought that the story of alien kidnapping is just an explanation for people's special liking for supernatural phenomena. People comfort themselves in their sleep, implying in their hearts that we are not alone in this universe.