In the morning, we will dress up in the mirror and start our day beautifully. When shopping, we will try on all kinds of new clothes in the mirror and enjoy it. It can be said that the mirror has been integrated into our daily life so that looking into the mirror has long become a habit. However, just like the bridges often used in horror movies, suddenly one day we don’t see ourselves in the mirror, you will definitely take a breath of horror. After thinking about it terribly, a question that was taken for granted now, but now “skeptical of life”, arises: why do we know that it is ourselves in the mirror? This problem is not simple, because behind it means one of the most important high-level cognitive functions of our human brain-self-awareness.
Consciousness is the most advanced and mysterious function of the human brain, and it is also the ultimate goal for scientists to study the brain. Self-consciousness, as the name suggests, is the recognition of the self, which distinguishes itself from other individuals in the environment. For human beings, self-awareness can include multiple levels. First, we have the cognition of our body, understand the state and position of each part of our body, etc. Second, we have the cognition of our mental state, understand our emotional character, etc. Recognize your position in society and understand your relationship with others. Self-awareness is also the basis of many other advanced cognitive abilities of human beings. Only when you recognize yourself and non-self can you have verbal communication and “you”, “I”, and “he”; only when you know yourself and others, Only the so-called “envy, jealousy, hatred” and other emotions. Because human beings have language, it doesn’t seem difficult to judge whether a person has self-awareness. We can judge directly by asking questions. So the question is, is there a sense of self-awareness in human newborn babies? Babies can’t speak, how can we judge their self-awareness? The mirror works, and scientists have come up with a way to paint the baby’s face with non-toxic and tasteless paint when the baby falls asleep. And try to wipe it off, we think that the baby has the ability to mirror self-recognition, this ability can be used to reflect self-consciousness. This test method is called “marking test” before the mirror. Through this test, scientists have found that human self-awareness is not innate. Babies generally do not pass the “marking test” until the age of two. This is why we often see little babies and mirrors having fun. It must be playing with the baby in the mirror as his little friend. From this point of view, our brain development needs to develop to a certain degree in order to have self-awareness.
Speaking of development, what about evolution? What about self-awareness in the evolution of species? Will the kittens, puppies, chicks, and ducklings in our house look in the mirror? It is often said that chimps are equivalent to the intelligence of a five-year-old child. The term general intelligence is obviously not very rigorous, but people can’t help thinking, then, do chimpanzees have self-awareness? In fact, scientists have long studied this problem. The “marker test” is a good way to test whether an animal has self-awareness. Some individuals in a few apes, such as chimpanzees, gorillas, bonobos, can pass the test and show spontaneous behavior. Act of looking in the mirror. Now that there is such a good method of “marking test”, then “is the mule or the horse pulled out?” Scientists have tested many other animals, and many of them have passed the test, such as dolphins, elephants, and magpie, which are considered to be very smart. However, the “marking test” is a bit problematic for these animals, because they do not have hands that can catch their faces, they can only make strange moves, such as the nose of an elephant, the fin of a dolphin, and the mouth of a magpie. So, it is questionable whether the results of this “marking test” with a bit of imagination are applicable. In addition, because too few individuals were observed, the experimental results also lacked repetition. So, whether these kinds of animals have self-awareness or not is left aside, because scientists are most concerned about whether monkeys look in the mirror. The reason is self-evident. Monkeys and us humans are primates. They are closest to each other in evolution, and the structure of the brain is similar to that of humans. The scientists researched for decades, found several monkeys, showed monkeys mirrors of various sizes and shapes, and even showed monkeys mirrors at birth. Unfortunately, no monkeys passed the mark test in previous studies. Therefore, it is generally accepted that only humans and a few apes have self-awareness.
At this time, the problem came again. From an evolutionary perspective, all of our biological characteristics should be traceable in evolution and can be traced to its roots. If self-awareness is judged by the standard of looking in the mirror, where does the self-awareness come from in the evolution process from monkey to apes? From nothing to nothing? Maybe the monkey has self-awareness, but there is a problem with the method of “marking test” in front of the mirror, which cannot reflect the monkey’s self-awareness. Here’s another clue. Although monkeys can’t pass the “mark test” and can’t look in the mirror, monkeys use mirrors. For example, if you put a banana behind the monkey’s side, the monkey can obtain the banana behind by looking at the image reflected in the mirror; if the monkey sees another monkey or a person coming from behind in the mirror, he will turn around Go find the monkey or person. In fact, not only monkeys but also other animals, such as birds, also use mirrors as tools to find objects that cannot be seen directly behind them or elsewhere. That is, the monkey knows the correspondence between the space in the mirror and the space in which he is, but he just doesn’t know that he is in the mirror. Maybe using the mirror as a tool to find things and looking in the mirror yourself are two different levels of brain function? This may sound strange, but one thing scientists realized is that monkeys may be a key entry point for studying the evolutionary origins and brain mechanisms of self-awareness.
The research team of the Chinese Academy of Sciences’ neuroscience research came up with a coup. They asked the monkey to sit on the monkey chair and train to the mirror. During the training, the monkey’s face was illuminated with a high-power laser pointer. The laser will shine a light spot on the monkey’s face, accompanied by a slight irritating heat sensation, which will guide the monkey to grab the light spot on the face (Figure 1). Therefore, the monkey can see in front of the mirror that he is scratching the light spot on his face with his hand. After 2 to 5 weeks of training, the monkey has learned the association between the light spot in the mirror and the light spot on his face. When the laser is shot on the monkey’s face with a low-power, non-sensing laser, the monkey can still be in front of the mirror. Touch the light spot on your face accurately. Trained monkeys can successfully pass the “marking test” in front of the mirror. In this experiment, seven monkeys trained only in there. 5 only showing a typical behavior of the mirror, the mirror that is able to self-identify, for example, pigments hand touch the face in the mirror after the marker, you will see A look, a smell, a lick of a finger, it’s like thinking “What’s on my face?” They will further spontaneously use mirrors to observe parts of their bodies that are usually invisible (Figure 2). This research is the first time that scientists have shown that monkeys can pass the “marking test” in front of the mirror. It seems that the monkey’s brain already has the basic “hardware” to identify the self in the mirror, but it needs proper training to obtain the necessary “software” to Achieve self-identification. In this study, the experimenter made a monkey show self-awareness from scratch, then scientists can use MRI and other experimental methods to monitor monkey brain activity in real-time to see if self-consciousness appears in brain activity. How it manifests, in other words, the self-conscious brain mechanism can be studied on monkeys.
Figure 1. Using a high-power laser pen to illuminate a red light spot on a monkey’s face, creating a heat sensation to induce the monkey to touch the light spot on the face in front of a mirror
Figure 2 The trained monkey passed the “marking test” in front of the mirror (left picture) and showed spontaneous mirroring behavior in front of the mirror (right picture).
This research result has further caused controversy. Accepted people believe that this discovery fills a gap in the evolution of advanced brain functions. We can use monkeys to study the neural mechanism of self-awareness. Opponents believe that human self-awareness It is generated spontaneously, and the trained self-awareness is just a simple conditional response. The past behavior is artificially induced and does not represent true self-cognition. In fact, this is not the first time such an argument has been made. In the 1980s, some scientists trained pigeons to pass the “marking test” in front of the mirror and proposed that pigeons also have self-awareness, and self-awareness is a product of learning. The debate over this pigeon research has continued to this day. The experimental dispute can only be resolved through experiments. The research team of the Institute of Neuroscience of the Chinese Academy of Sciences has redesigned the experimental scheme. They distinguished the rhesus monkeys from “learning to use a mirror as a tool” and “seeing yourself using a mirror”. This time, they no longer project the laser spot on the face of the rhesus monkey for training, but hit the laser red dot on the cardboard near the rhesus monkey, so that it can only see the light spot through the mirror, and then use the image in the mirror to track and grab the red dot on the cardboard (Figure 3). When the three rhesus monkeys trained can accurately use the mirror image to touch the light spots on the cardboard, the experimenter moved the light spots to the monkey’s face and found that all three monkeys could accurately touch the face. The light spot passed the “marking test” in front of the mirror spontaneously, and showed a typical behavior of looking in the mirror, that is, using the mirror to check the parts of the body that could not be seen. This time, they once again proved that rhesus monkeys do have the ability to mirror self-recognition and that this ability was only spontaneously demonstrated by monkeys trained to use mirrors as tools. More importantly, this experiment also made scientists realize that even the most classic tests may have their limitations. Take the “marking test” in front of a mirror. If an animal fails the test, it may be because it does not use a mirror, not because it is not self-aware. If we improve or create new test methods, perhaps humans will find that more Many animal friends around you, like yourself, have self-awareness.
Figure 3 Train a monkey to use a mirror as a tool to touch the red dot on the cardboard around him.
In fact, scientists have thought of other tactics for studying self-awareness. There is a classic experiment called the “rubber hand effect”. In simple terms, a rubber prosthesis with a shape and a position close to each other is placed on the side of the real arm of the subject, and the real arm of the subject is blocked. Only the rubber hand can be seen. At this time, the experimenter used a brush to stimulate the real arm and the rubber prosthesis at the same time. After a certain period of time, the subject would have the illusion that the rubber hand is his real body. When the experimenter struck the rubber hand hard, the test subject The person will retract his real arm. The “rubber hand effect” can also be extended to the entire body. Some scientists have tried a kind of “soul-extracting” experiment, which brought the participants a pair of virtual reality glasses, which saw themselves after being processed by the camera. The back of the body is used to stimulate the subject’s back with a brush or the like. At the same time, the virtual body stimulus can be seen in the virtual reality glasses. After a certain period of training, the subject will also have the illusion that they see in the glasses It is his real body, and the virtual operation of the virtual body will also cause the subject’s real body to react. The “rubber hand effect” and the “soul out of touch” reflect a kind of self-awareness of the body, which can also represent some level of self-awareness. Now, scientists are trying to use these experimental methods to study monkeys. We can wait and see and see what magical performance Sun Dasheng can bring us.