From unreliable to a little reliable.
Editor’s note: This article comes from the WeChat public account “Brain pole body” (ID: unity007) , author Hai strange.
Sleep learning, as the name suggests, is to enhance human learning ability through sleep.
This concept contains two meanings. The first one is to discuss whether “sleep can consolidate what we learn when we are awake”; the second is to discuss “can we learn new things during sleep”?
Let ’s open a brain hole first.
If Lao Zhuang Zhou lived in modern times during the Warring States Period, how would he view this issue? It is estimated that Zhuang Zhou may feel that human beings are already ill.
We know that Zhuang Zhou once said, “My life also has an end, and knowledge also has an end, so there is end to end, and endless”, that is to say, the reserves of knowledge are endless. It is dangerous to pursue endless knowledge. Now we not only have to waste when we are awake to learn, but also take sleep to pursue new knowledge. Isn’t this crazier?
Despite that, Zhuang Zhou was actually one of the few most knowledgeable scholars at that time. Today, he is estimated to be an arrogant scholar in a college. On the one hand, he vigorously promotes the naturalism theory of human nature, and on the other hand, he explores the mysteries of life of “Zhuang Zhou Meng Die, Die Meng Zhuang Zhou”.
No way. This is due to human curiosity and curiosity The growth of knowledge (of course most of it is only information) has caused modern people to squeeze sleep time over and over. Since the learning potential when we are awake has been tapped out, it is better to seize the potential by sleeping for one third of our lives.
Can we really learn while sleeping? Some studies in recent years are trying to prove this. Before introducing and evaluating these studies in detail, we can first review the secrets related to sleep and learning that scientists have discovered, and the experiments that they have done that are a bit “open brain”, and finally we will look at Current research and problems in sleep learning.
From sci-fi into reality, the “barbaric exploration history” of sleep learning
The germination of new scientific knowledge comes from bold assumptions and conjectures, such as “a small ball slides from the slope toWill this absolutely smooth surface go on endlessly? “” “If I can catch the light, will the time slow down?” “
So we ca n’t laugh at any “whimsy” easily. For example, we keep repeating some knowledge to a person who is asleep. Will this person remember when he wakes up?
Compared to the imagination of “frictionless plane” and “chasing the speed of light”, it is very easy to speak to a person at night when people are quiet. It is said that ancient Buddhist monks would recite the Scriptures in the ears of sleeping young monks to help them remember and understand the scriptures more easily. As for the effect, we have no way of knowing it. Just as countless mothers put Mozart on children in the womb, it is difficult to get accurate results statistics.
But some scientists really want to confirm this.
In 1942, American psychologist Professor Lawrence LeShan designed such a sleep intervention experiment. In the New York State Men’s Summer Camp, he selected a group of children who have the habit of biting their fingers and assigned them to two different wooden houses. One group is the “sleep learning” group, and the other is the reference comparison group.
Every time the child in the “sleep learning” group falls asleep, the gramophone placed in the room will continue to play suggestive words like “It’s not good to bite my finger, my finger is very bitter”. Among the 16,000 sentences about “biting fingers” that were broadcast, some of them were still after the phonograph failed, and Professor LeShan went in and read them to the children in the middle of the night!
Finally, after checking the fingernails of all the children, 40% of the children in the “sleep learning” group changed their bad habits of biting their fingers, and none of them in the control group corrected them. This experiment seems to successfully prove that language instillation during sleep can affect people’s behavior.
The 20th century is really the golden age of scientific and social experiments! Affected by this, in the United States in the 1950s, a county prison also began to use this method to change the prisoners’ bad habits and help them re-become life.
At the same time, the Soviet Union was also involved in this experiment. They were determined to carry out a larger social experiment because they worried that Americans would win the opportunity of sleep learning.
The Soviet Union directly chose a small town where 20,000 people lived to start the experiment. For two months from the end of 1967, the researchers asked the local villagers to turn on the radio before going to bed, and uniformly set the sleeping time. After midnight, the radio will broadcast a series of English lessons on time. The scientists who were ultimately responsible for the project reported that the villagers in the village hadI learned 1,000 English words without knowing it, and I can also have a simple English conversation.
It is conceivable that these “experiments” have various loopholes, at least they cannot confirm whether the subjects are really asleep.
The children in Professor LeShan ’s experiment are likely to be awake to really hear these threats about biting their fingers, not to mention may hear the professor in the dark personally “training”; the prisoners may be in order to obtain good Acting and deliberately showing what the prison wants; and the residents of the Volga town may have already woken up at night and studied these English programs seriously. I don’t know if it would have such a good effect if I switched to Chinese at that time.
In order to verify the experimental conclusion of Professor LeShan, in 1956 William Emmons and Charles Simon of Rand Corporation reset the research experiment of stricter sleep learning, because the volunteers brought EEG monitoring equipment, the experiment will be in It was confirmed that they really started to play after falling asleep. Finally, the test proved that the subjects could not clearly indicate the words heard during sleep.
Since then, a series of experiments have proved that the “sleep learning effect” is unbearable.
Of course, scientists have neither given up the study of sleep nor the study of the effect of sleep on learning. At least with the progress of brain science, we have learned some more very positive conclusions.
Enhancement of memory: Sleep itself is a kind of learning
Regarding sleep research, the two major advances in the 20th century were the discovery of sleep cycles and rapid eye movements.
The study found that the average person’s sleep has a sleep rhythm of about 90-100 minutes, during which it will experience a non-rapid eye movement period (NREMs) and a rapid eye movement period (REMs) from shallow to deep sleep. Among them, the REM period is regarded as the main basis for people’s dreams, and it is also regarded as the key stage of the brain’s memory integration.
In 2015, a report published by the research team at the University of Tsukuba, Japan, in Science pointed out that they found a nerve cell that can switch between REM sleep and non-REM sleep.
By controlling this cell, reducing the duration of sleep in the REM phase will reduce the appearance of a delta wave brain wave in the non-REM phase. And Delta brain waves can strengthen the connection between nerve cells, is believed to increase the body’s auxin secretion, but also related to enhance people’s learning and memory ability.
This conclusion has already been proved by a large number of comparative experiments.
From the perspective of how much sleep time you have, adequate sleep and insufficient sleep have a huge impact on people ’s ability to learn and remember. In a test of a group of elementary school students by the Avi Sad team of Tel Aviv University in Israel, a group of students who were asked to sleep half an hour earlyIn multiple tests for students who asked to sleep for half an hour late, the performance of children who had insufficient sleep showed a significant regression.
In addition, in a survey of a large number of high school students in the United States, the students with the highest rankings are 45 minutes earlier in bed time and 25 minutes longer in sleep than those with poor grades. A high school adjusted the morning class time from 7 to 8:30, and the average grades of students also increased significantly.
Obviously, in this modern society where sleep is a luxury, more sleep time may be more conducive to improving the quality of learning.
From the perspective of memory, sleep also helps memory.
In 2007, this conclusion was confirmed in an “Egg Experiment” led by Harvard University. Compared with the “wake group” who studies the evening exams during the day, the “sleep group” who studies the day exams at night is 24% higher in the recognition rate of the hierarchical relationship of the eggs. After 24 hours of testing again, the accuracy rate of the sleeping group was still 35% higher than that of the awake group.
The wake-up group studying during the day originally had more time to remember, but the testers who spent most of their time sleeping have remembered more words, which is indeed counterintuitive.
Researchers analyzed that the picture of memory may be widened during sleep, and there is evidence that the time this memory is widened occurs during the rapid eye movement period, during which the brain carries out memory information Organizing work, thus strengthening and consolidating what we learned when we were awake.
In addition, the researchers found that a short nap during the day, from 6 minutes to 1 hour, can also bring a great improvement in memory. These examples are not only suitable for children, but also for any professional or professional. At the same time, taking a nap can also reduce the risk of cardiovascular and cerebrovascular diseases.
This discovery is actually very much in line with people ’s experience, and many people have a personal experience of “no sleep at noon, collapse in the afternoon”. And now you may be more confident in telling the results of the research that thinks that lunch break is a lazy leader. As an example, you can say that Google has placed some “lunch breaks” in the headquarters as early as 2010 to ensure that the employees recover their energyIn the afternoon, you can achieve better work efficiency.
Of course, merely discovering the causal link between sleep and learning will never satisfy the curiosity of scientists. Some researchers will go further and experiment with various variables related to sleep and learning and memory.
From enhancing “sleep learning” to sleep “learning” new knowledge
Alders Huxley, in “The New World of Beauty” published in 1931, described a way of sleep learning, which is also similar to the practice of the county prison in the United States. After the children fell asleep, Use radio to softly play some prejudiced content, so as to adapt them to their social class.
Although this idea is dark and dystopian, it still stimulates people’s strong interest and imagination in sleep learning. There is a huge gap between “sleep helps to consolidate new knowledge of learning and memory” and “sleep can learn new knowledge”. But does it contain a possibility to cross this gap?
In 2004, a research team at the University of Tübingen, Germany, tried to investigate whether the “transcranial direct current stimulation” (tDCS) can affect memory by discharging brain waves that affect sleep. They wanted to stimulate their brain precursors with electrical current when the subjects entered deep sleep. After several days of controlled trials (sometimes energized, sometimes not), subjects were able to remember more words after receiving current stimulation.
In 2007, researchers at the University of Lubic in Germany tried to influence this sleep learning process through smell. They designed a memory game before going to bed, and the testers would smell the roses during the learning process. After they enter deep sleep, the researchers will let them smell the roses again. The final result test, as expected, after smelling the smell of roses after sleeping, the memory effect is better than when there is no smell. The researchers analyzed that it is likely that the taste brain area is connected to the hippocampus, which is more likely to affect memory.
So, along with visual memory, what about sound stimulation? Inspired by odor experiments, the cognitive neuroscientist Ken Paller of Northwestern University in the United States used pictures accompanied by specific sounds to test. They found that those pictures that played sounds during sleep were easier to remember than those without sounds.
Paller has further experimented. If he plays a certain piece of music to a sleeping person, he wakes up and scores the same piece of music in the game “Guitar Hero”Will be higher.
This not only proves that sleep helps memory learning, but by adding certain stimulating factors during the deep sleep stage, the effect of memory learning can be improved or further enhanced.
Does this mean that the balance is moving closer to “learning new knowledge in sleep”?
Yes. As we all closed our eyes tightly during sleep, we closed the largest visual organ, but we still retain hearing and breathing, we can hear sounds and smell odors. The researchers found that during slow wave deep sleep rather than rapid eye movement sleep, the stimulation of sound and smell activates the brain’s memory. Although we wake up unconscious, we react to the sound or smell we hear during sleep.
Now, the next step is naturally to test the language information stimulation of sleep.
In January 2019, the latest research published by the University of Berne in the journal Current Biology found that the sleeping brain can encode new information and save it for a long time, and more importantly, it can also establish new contact.
Researchers designed a vocabulary test. The subject will hear a pair of physical words during slow wave sleep, one is a made-up foreign language word, and the other is a so-called translation of the word, such as “biktum” and “bird”. Hear a series of fabricated words, and then let them judge whether the object represented by the word is larger than the shoe box to test the hidden words that were heard during sleep.
The results prove that the correct rate of the classified words that the subjects heard in sleep is 10% higher than that of random classification. During the test, MRI also showed that when the subject heard the new words learned, the hippocampus and language-related areas of the brain were activated.
This means that memory is still functioning during sleep, and the vocabulary heard during sleep is combined to remember.
However, this experiment still has limitations, that is, it still uses the brain’s associated memory for sound, rather than semantic understanding. That is, it has not been proven that the sleeping brain can learn new languages or remember new vocabulary.
Of course, maybe you think I will think the same way, I hope that the study of sleep learning will probably stop here. If we stimulate some sounds and smells during sleep, we can improve our art appreciation, musical sensibility, or change bad habits such as smoking and alcoholism. This is already a very powerful effect.
If you go in againOne step is to let people learn something new when they sleep, such as learning a new language or a new concept, by using some equipment or ordering some medicine. Think about whether you feel “Beautiful New World” The prophecy is approaching reality again.
But we know that researchers will not stop there, and those commercial organizations will not give up. As far as memory is concerned, the endless stream of health products and various instruments is already a very large industry, not to mention the hundreds of billions of commercial scale brought about by insomnia or sleep disorders. This makes business people want to become scientists.
As ordinary people, we all know the benefits of more sleep on the body and learning. But when it comes to unfinished dramas, short videos that can’t be finished, new knowledge that can’t be learned, who has the heart to put down the phone before zero and sleep well.
Eating melatonin for a long night, what a painful realization!
If there is really a way in the future that we can learn everything we can learn and play when we sleep, is there still a little excitement?