Can one really "get out of the body"?

The sense of self is the result of a very complex interaction between the brain and the nervous system of a person and depends on the "input information" supplied by the senses. If a malfunction occurs in the brain or nervous system, amazing, though not joyful, things happen to our personality. For example, as a result of damage to the parietal lobe, a disorder called somatoparaphrenia can occur. In this case, the patient ceases to feel his left arm or left leg as part of himself. It may even seem to him that someone else is controlling his own limbs. Another disease - one-sided spatial agnosia - leads to the fact that the patient simply ignores half of his body, as if it simply does not exist. For example, a woman applying makeup will apply powder, shadow or mascara to only one half of her face, leaving the other completely untouched. In another case, a person suffering from such a disease will eat exactly half of the dish from his plate, being in complete confidence that everything is eaten. If the plate is rotated 90 °, the patient, as if nothing had happened, will eat the second half of the porridge or salad.

“I” and “This” Humanity has long been asking itself questions about where the “I” ends and the world around us begins and whether an individual can feel himself outside the body.

Rubber hand

However, games with the consciousness of completely healthy people can lead to unexpected results. An amazing experiment is known, set by a group of scientists from the Department of Neuropsychology of the Carolingian Institute (Stockholm), led by Dr. Henrik Ersson. The experiment demonstrates the so-called "illusion of a rubber hand." The test subject sits down and lays a palm on the surface of the table. The hand is fenced off with a small screen, so that the participant in the experiment does not see it, however, immediately before it on the same table, a rubber dummy of the human hand is laid out. Now a member of the research team picks up brushes and starts simultaneously stroking the subject’s hand and a rubber dummy in the same places. A small miracle happens: after a while the visual information “clogs” the natural feeling of owning one’s own hand. It begins to seem to the participant of the experiment that the sensations of stroking with a brush come from a piece of rubber.


People and iron

The contingent of subjects for the experiments that were conducted within the walls of Carolingian University by Henrik Ersson, Valeria Petkova and their colleagues was selected among young men and women aged about 18 to 34 years.

In a scientific article, Swedish researchers write that the main criterion for selection is health and naivety. Probably, it was meant that girls and young people with excessive intellectual baggage and their own ideas about the nature and purpose of the experiments can consciously or unconsciously distort the results of experiments, answering questionnaires, guided not only by direct impressions, but also by their ratings. Getting out of the body is a serious matter, therefore, all potential subjects gave written consent to participate in the experiments. A positive conclusion was also received from the Ethics Committee of the Carolingian University of Stockholm.

As already mentioned, the equipment for the experiments was comparatively simple and consisted of video glasses with a resolution of 640x480, giving a real stereoscopic picture and differing in wide viewing - 71.5º. They were connected by radio with synchronized color surveillance cameras mounted on special helmets. The distance between them was adjusted to match the distance between the eyes of a particular subject. The signal from the cameras was fed directly to the video glasses without any software processing, as a result of which there was practically no difference between the visible reality and the image. The most difficult element of the experimental equipment was, of course, a device for measuring skin conductivity. It was released by Biopac Systems and took data from electrodes mounted on the subject's middle and index fingers.

In other words, a person is able not only to “believe” that a part of the body does not belong to him, but also to feel completely “his” foreign object. An illusion is born in the so-called premotor region of the cerebral cortex, where neurons are located that receive both tactile and visual information and integrate data from both sources. It is this part of our “gray matter” that is largely responsible for the feeling of owning our own body, drawing a line between “I” and “not me”. And so, as studies by Swedish scientists have shown, in deceiving your own brain you can go much further and not only recognize your rubber hand, but ... feel yourself outside your own body. This is clearly demonstrated by the experiments of Henrik Ersson and his colleague Valeria Petkova.

First person

One of the main factors that allows us to feel the possession of our own body is the position of the eyes fixed in relation to the head, trunk and limbs, that is, what we call “first-person vision”. Inspecting ourselves, we always find all parts of our body oriented in a known manner relative to each other. If, with the help of rather simple tricks and devices, the “picture” is changed, the test subject may have the illusion of not only being in a different point from the space other than real, but also of moving his “I”. During the experiments, their participants felt themselves in the body of another person and even met with the “real self” face to face, shaking hands with him. All this time, the illusion persisted.

One of the simplest experiments, during which the illusion of moving to another body was noted, was carried out using a mannequin. A helmet was put on the head of a standing mannequin, to which two electronic video cameras were attached. The body of a mannequin appeared in their field of vision - this is how we see our body from the first person, slightly tilting our head. Here in this position - with his head bowed forward - the subject stood opposite the dummy. He wore video glasses, on each of which screens a “picture” was fed from video cameras on a mannequin helmet. It turned out that the participant in the experiment, looking as if at his body, saw in the glasses the body of a mannequin.

Further, the laboratory employee took two sticks and began to make synchronous movements, gently stroking the lower abdomen of both the test subject and the mannequin. For control and comparison, in some experiments, stroking series were out of sync. After the experiment, the subjects were asked to fill out a questionnaire in which they had to evaluate each of the probable sensations on a seven-point scale. As it was found out, illusions began to arise with synchronous stroking, and with asynchronous strokes they disappeared completely or appeared slightly. The most powerful sensations were the following: the participants in the experiment felt a touch on the body of the mannequin; it also seemed to them that the mannequin was their own body. Some subjects felt that their body became plastic or that they had two bodies.


View from the outside

The theme of going beyond the body lies on the verge of medicine, psychology and mysticism.

Cases where the patient saw himself as if from above or from above were recorded by doctors and are often cited by the authors of books about the “near-death experience” as evidence of the independent existence of the human soul and confirmation of faith in the underworld. However, precedents of spontaneous exit from the body may have explanations that do not go beyond the scientific understanding of human biology.

One of these cases was of great interest to the Swiss neuropsychologist Olaf Blancke, who at that time was an employee of the University of Geneva Hospital. An elderly woman said that once she felt herself soaring above her body lying on a hospital bed. At this point, the patient underwent a course of treatment for epilepsy, during which the so-called angular gyrus of the cerebral cortex was simulated by electric current using a supplied electrode. Interestingly, it is the angular gyrus that is largely responsible for the orientation and sensation of the body. “The patient was not even scared, ” Blanca later said. “She only said that leaving the body was a very strange sensation.”

Being interested in the mechanisms that attach the human “I” to the body, Blanque conducted a series of experiments at the Federal Polytechnic School in Lausanne (Switzerland) that were generally similar to the experiments of Ersson and Petkova.

In one of these experiments, a stereo camera was placed behind the subject’s back, and in video glasses he watched his 3D image from the back. Then a plastic wand appeared in the field of view of the cameras, aimed just below the cameras, approximately at the level of the participant’s chest, and he felt that a touch could happen now .. At the same time, the other wand really touched the subject’s chest. He had the illusion that his body was in front, that is, where his virtual image is visible. The experiment had a very interesting ending. Subjects were turned off their glasses and blindfolded, and then asked to step back a few steps. After that, the experimenter invited the participant to return to the old place. However, each time the attempt was unsuccessful. Subject took more steps than necessary, trying to take the place of his virtual alter ego.

Fear lives in the skin

In another experiment, it was decided to use not only the subjective sensations of the subjects, but also objective indicators associated with changes in the electrochemical properties of the skin to confirm the "relocation" to another body. This is a measure of the reaction of skin conduction, which changes if a person experiences fear or feels danger. The beginning of the experiment completely coincided with the previous one, however, after a series of synchronized stroking, the subject saw in his video glasses how a knife appeared next to the mannequin’s stomach, which cuts the “skin”. For control and comparison, in some cases, the initial strokes were out of sync. In other experiments of the series, the mannequin’s stomach was “threatened” with a similar in size, but not so formidable metal object - a tablespoon. As a result, the greatest increase in the index of skin conduction reaction in the subject was observed precisely when, after a series of synchronized stroking, the mannequin received an incision with a knife. But even with asynchronous strokes, the knife still excelled in front of a spoon, clearly less frightening the subject, who seemed to be a mannequin.

But in fact, is it so fundamentally important for the illusion that the subject to contemplate through his video glasses exactly the model of the human body? Yes, the habit of seeing "in the first person" is the body that plays a key role in the occurrence of the effect. Special experiments in which the mannequin was replaced by a rectangular object that did not have anthropomorphic outlines showed that the illusion of a sense of belonging to a foreign object in this case usually does not arise.

However, strangely enough, gender does not play any role in creating an illusion. In the experiments of Swedish researchers, a mannequin was used that uniquely reproduces the features of the male body. At the same time, both women and men were among the subjects. When the knife threatened the mannequin’s stomach, the skin conductivity reaction showed almost the same indicators for both sexes. So for the illusion of moving into someone else’s body it is not required that it be like yours. It is enough that it be human.

Deceptive handshake

The theme of the exchange of bodies between two "I" formed the basis of the plots of many films and science fiction novels, however, it is rather difficult to imagine this in reality. It is much easier to make a person at least temporarily believe that this is possible, and not in the cinema, but in a scientific laboratory.

The experiment with the "exchange of bodies" was organized as follows. A block of two video cameras was installed on the experimenter's head, which captured the reality as it was seen by the eyes of a researcher. Exactly the opposite, in the field of view of the cameras, the subject stood in video glasses. As you might guess, the video “broadcast from the first person”, such as the eyes of the experimenter, was broadcast on the video glasses. At the same time, the participant in the experiment saw himself in glasses from about the head to the knees. The subject was offered to stretch his right hand forward and shake the hand of the experimenter. Then the experimenter and the subject had to squeeze and unclench their hands several times within two minutes. First, the shakes were carried out simultaneously, and then asynchronously.

Subsequent interviews with the subject showed that during the experiment there was a strong illusion of relocation to someone else's body. The subject began to perceive the experimenter's hand as his own, since he saw his own body behind it. Moreover, it seems that the situation was such that the tactile sensations arising from the handshake went to the subject’s brain precisely from the experimenter's hand, and not from his own hand visible in front of him.

It was decided to complicate the experience with the introduction of an additional, “threatening” factor into it. At the time of the handshake, the laboratory technician would use a knife on the wrist of either the experimenter or the subject. Of course, the skin was protected by tapes of a dense patch, so that in reality there were no traumatic consequences of contact with edged weapons. However, when measuring the test of the skin’s conductivity, it turned out that this indicator was much higher then the knife “threatened” the experimenter's wrist. The foreign hand clearly seemed to the brain "closer to the body."

World of illusion

In psychology, illusion is an incorrect, distorted interpretation by the brain of signals from the senses. Illusion should not be confused with hallucination, since hallucination can occur in the absence of any effect on the receptors and is the result of painful changes in consciousness. Illusions are able to feel quite healthy people.


Money issue

Another entertaining tactile illusion can easily be demonstrated with coins, preferably larger ones. One coin should be slightly warmed up, for example, by putting a table lamp under the light, and the other should be kept in the refrigerator for half an hour. Now if you put the cold and warm coins at the same time on the back of your hand, a paradoxical feeling will appear: a cold coin is heavier! Pressure receptors located in the skin are responsible for determining weight. By temperature, they are supposed to be indifferent. However, as it turns out, they are still sensitive to it, and it is to the cold. However, in contact with a cold object, pressure receptors send information to the brain not about a lower temperature, but about a stronger pressure. More precisely, this is how the brain interprets this information. The question of which is heavier - a kilogram of cast iron or a kilogram of fluff - is among the number of children's draws, however, among two balls of the same weight, we will certainly feel that the one with the larger radius is heavier. Say what you like, but our feelings fool the brain not so rarely.

We have been familiar with optical illusions since childhood: which of us did not look at static patterns that suddenly begin to move, dark spots at the intersection of absolutely white lines separating black squares from each other, or segments of equal length in which the eye does not want to recognize equality. Auditory and tactile illusions are much less known, although some of them demonstrate very unusual properties of the “brain - nervous system” ligament.

Even Aristotle discovered the illusion of two balls. If you cross two fingers, the index and the middle, and roll the small glass ball with the tips of these fingers, closing your eyes, then it seems that there are two balls. Roughly the same thing happens if one of the crossed fingers touches the tip of the nose, and the other on its side. If you choose the right position of the fingers, while also closing your eyes, you will feel two noses.

Another interesting tactile illusion is associated with the nerve receptors of the skin of the wrist and elbow. If you consistently conduct a series of light taps, first in the wrist area, and then in the elbow area, then after that without any physical impact either in the elbow area or in the wrist area, alternating tremors will be felt, as if someone is jumping back and forth. This illusion is often called the rabbit illusion.

Due to the fact that the density of receptors that respond to pressure in different parts of the body is different, an interesting effect of a converging compass occurs. Если закрывшему глаза испытуемому слегка покалывать кожу на внешней стороне кисти руки разведенными ножками циркуля, а потом, медленно сводя их, повторять укол, то на определенном расстоянии между ними испытуемый перестанет чувствовать прикосновение двух ножек и ощутит лишь один укол.

Температурные рецепторы слегка обманывают мозг, когда одну руку, вынутую из тазика с горячей водой, и другую руку, вынутую из тазика с ледяной водой, мы опускаем в третий тазик — с теплой водой. Одной руке в этом случае теплая вода покажется горячей, а другой — прохладной. Механизмы тактильных иллюзий очень разнообразны, но часто значительную роль в их возникновении играет память.

Почему, дотрагиваясь до носа или до стеклянного шарика скрещенными пальцами, человек ощущает два предмета вместо одного? Да потому что таким образом мы сводим вместе рецепторы, которые в обычной жизни практически никогда не касаются одного и того же предмета. В результате объект раздваивается. В процессе принятия решений к информации, поступающей непосредственно от рецепторов, мозг добавляет некое первичное знание, полученное в течение жизни. В большинстве случаев это приводит к тому, что решения принимаются точнее и быстрее, но иногда этим можно воспользоваться с тем, чтобы ввести «серое вещество» в заблуждение.

Такой же механизм срабатывает в иллюзии обмена телами, которую сумели воспроизвести Хенрик Эрссон и Валерия Петкова. Ведь для правильной ориентации собственного тела в пространстве и для ощущения принадлежности своему «я» туловища и конечностей ведущую роль играет взгляд на себя «от первого лица». Найдя способ подменить этот взгляд, исследователи разрушили казалось бы нерушимую связь между телом и индивидуальным сознанием.

Важно заметить, что взгляд «от первого лица» на себя со стороны — это нечто совершенно иное, нежели узнавание себя в зеркале, на экране или фотографии. Все дело в том, что жизненный опыт подсказывает нам, что «я» в зеркале — это не «я», то есть мы имеем дело со взглядом со стороны, «от третьего лица».

Для роботов и богословов

Шведских исследователей интересуют не просто игры с человеческим сознанием. По их мнению, эти опыты будут иметь серьезное значение и для науки, и для медицины, и для промышленности. Например, данные, полученные при «обмене телами», смогут помочь лучше понять природу соматопсихических расстройств — вроде тех, что упоминались в начале данной статьи, а также проблем идентичности в социальной психологии.

Эксперименты шведов также имеют непосредственный выход на проблематику, связанную с конструированием дистанционно управляемых роботов и систем виртуальной реальности, в которых человек зачастую управляет своим электронным alter ego именно от первого лица.

Ну и наконец, нельзя исключить, что отчеты нейропсихологов из Стокгольма о том, как с помощью нехитрого приспособления заставить человека ощутить себя манекеном, станут отправной точкой дебатов мировоззренческого, а может быть, даже религиозного характера. О том, что связывает душу и тело, издавна рассуждают богословы, а представители европейских школ иррационалистической философии не раз пытались ответить в своих трудах на вопрос, что отделяет «я» от окружающего мира, где проходит тонкая граница между «быть» и «иметь». Не то чтобы на вопросы богословов и философов наконец-то найден ответ, но порассуждать на эту тему еще раз с учетом данных современной науки, возможно, очень даже стоит.

Статья «Так просто выйти из себя» опубликована в журнале «Популярная механика» (№2, Февраль 2009).

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