Brain and soul. How neural activity shapes our inner world

Chris Frith

The famous British neuroscientist Chris Frith is well known for his ability to talk simply about very complex problems of psychology - such as mental activity, social behavior, autism and schizophrenia. It is in this area, along with the study of how we perceive the world around us, act, make choices, remember and feel, that today there is a scientific revolution associated with the introduction of neuroimaging methods. In Brain and Soul, Chris Frith talks about all this in the most accessible and entertaining way.

Chris Frith

All Rights Reserved. Authorized translation from the English language edition published by Blackwell Publishing Limited. Responsibility for the accuracy of the translation rests solely with The Dynasty Foundation and is not the responsibility of John Blackwell Publishing Limited. No part of this book may be reproduced in any form without the written permission of the original copyright holder, Blackwell Publishing Limited.

CORPUS® Publishing

All rights reserved. No part of the electronic version of this book may be reproduced in any form or by any means, including posting on the Internet and corporate networks, for private and public use, without the written permission of the copyright owner.

Dedicated to Uta

List of abbreviations

ACT - axial computed tomography

MRI - magnetic resonance imaging

PET - positron emission tomography

fMRI - functional magnetic resonance imaging

EEG - electroencephalogram

BOLD (blood oxygenation level dependent)

Foreword

I have an amazing labor-saving device in my head. My brain - better than a dishwasher or a calculator - frees me from the boring, repetitive work of recognizing things around me and even saves me from having to think about how to control the movements of my body. This gives me the opportunity to focus on what is really important to me: friendship and the exchange of ideas. But, of course, my brain doesn't just save me from tedious daily work. It is he who forms the me, whose life takes place in the society of other people. In addition, it is my brain that allows me to share with my friends the fruits of my inner world. So the brain makes us capable of something more than what each of us is capable of individually. This book is about how the brain performs these miracles.

Thanks

My work on the mind and brain was made possible by funding from the Medical Research Council and the Wellcome Trust. The Medical Research Council gave me the opportunity to work in the neurophysiology of schizophrenia through the financial support of the Tim Crow Psychiatric Unit at the Northwick Park Hospital Clinical Research Center in London, Harrow, Middlesex. At that time, we could judge the relationship between the psyche and the brain only on the basis of indirect data, but everything changed in the eighties, when tomographs were invented to scan the working brain. The Wellcome Trust enabled Richard Frackowiak to set up the Functional Imaging Laboratory and financially supported my work in that laboratory on the neurophysiological basis of consciousness and social interactions. The study of mind and brain is at the intersection of many traditional disciplines, from anatomy and computational neuroscience to philosophy and anthropology. I have been very fortunate to have always worked in interdisciplinary – and multinational – research groups.

I have benefited a lot from my colleagues and friends at University College London, especially Ray Dolan, Dick Passingham, Daniel Wolpert, Tim Shallis, John Driver, Paul Burgess and Patrick Haggard. In the early stages of writing this book, I was aided by many fruitful discussions about the brain and psyche with my friends in Aarhus, Jakob Howu and Andreas Röpstorf, and in Salzburg with Josef Perner and Heinz Wimmer. Martin Frith and John Law have been arguing with me for as long as I can remember about everything in this book. Eva Johnstone and Sean Spence generously shared with me their professional knowledge of psychiatric phenomena and their implications for brain science.

Perhaps the most important impetus for writing this book came from my weekly conversations with past and present breakfast parties. Sarah-Jane Blakemore, Davina Bristow Thierry Chaminade, Jenny Kull, Andrew Duggins, Chloe Farrer, Helen Gallagher, Tony Jack, James Kilner, Haguan Lau, Emiliano Macaluso, Eleanor Maguire, Pierre Macke, Jen Marchant, Dean Mobbs, Matthias Pessilone, Chiara Portas, Geraint Rees, Johannes Schultz, Suchy Shergill, and Tanya Singer helped shape this book. I am deeply grateful to all of them.

To Karl Friston and Richard Gregory, who have read portions of this book, I am grateful for their invaluable help and valuable advice. I am also grateful to Paul Fletcher for supporting the idea of introducing an English professor and other characters who argue with the narrator early on in the book.

Philip Carpenter selflessly contributed to the improvement of this book with his critical remarks.

I am especially grateful to those who read all the chapters and commented in detail on my manuscript. Sean Gallagher and two anonymous readers have made many valuable suggestions for improving the text of this book. Rosalind Ridley made me think carefully about my statements and be careful with terminology. Alex Frith helped me get rid of professional jargon and lack of coherence.

Uta Frith actively participated in this project at all its stages. If she had not set an example and guided me, this book would never have seen the light of day.

Prologue: Real Scientists Don't Study Consciousness

Why psychologists are afraid of parties

Like any other tribe, scientists have their own hierarchy. The place of psychologists in this hierarchy is at the very bottom. I discovered this in my freshman year at university where I was studying science. We were told that college students would, for the first time, have the opportunity to study psychology in the first part of the science course. Encouraged by this news, I went to our group leader to ask him what he knew about this new opportunity. “Yes,” he replied. “But it never crossed my mind that one of my students would be so dumb as to want to study psychology.” He himself was a physicist.

Because, probably, that I was not quite sure what "stupid" meant, this remark did not stop me. I left physics and took up psychology. From then until now, I have continued to study psychology, but I have not forgotten my place in the scientific hierarchy. At parties where scientists gather, from time to time

Page 2 of 23

The question inevitably pops up: “What do you do?” - and I tend to think twice before answering, "I'm a psychologist."

Of course, much has changed in psychology in the last 30 years. We borrowed a lot of methods and concepts from other disciplines. We study not only behavior, but also the brain. We use computers to analyze our data and model mental processes. My university badge doesn't say "psychologist" but "cognitive neuroscientist."

Rice. item 1. General view and section of the human brain

Human brain, side view (top). The arrow marks the place where the cut shown in the bottom photo passed. The outer layer of the brain (cortex) consists of gray matter and forms many folds that allow you to fit a large surface area in a small volume. The cortex contains about 10 billion nerve cells.

And they ask me: “What do you do?” It seems to be the new head of the physics department. Unfortunately, my response “I am a cognitive neuroscientist” only delays the denouement. After my attempts to explain what, in fact, my work consists, she says: “Ah, so you are a psychologist!” - with that characteristic facial expression in which I read: “If only you could do real science!”.

A professor of English joins the conversation and raises the topic of psychoanalysis. She has a new student who "doesn't agree with Freud in many ways." In order not to spoil my evening, I refrain from suggesting that Freud was an inventor, and that his discussions about the human psyche are of little relevance to the case.

A few years ago, the editor of the British Journal of Psychiatry, apparently by mistake, asked me to write a review of a Freudian article. I was immediately struck by one subtle difference from the articles I usually review. As with any scientific article, there were many references to the literature. Basically, these are links to works on the same topic, published earlier. We refer to them partly in order to pay tribute to the achievements of their predecessors, but mainly in order to support certain statements that are contained in our own work. “You don't have to take my word for it. You can read a detailed rationale for the methods I used in Box and Cox (Box and Cox, 1964).” But the authors of this Freudian article did not at all try to back up the cited facts with references. References to the literature were not about facts, but about ideas. Using references, it was possible to trace the development of these ideas in the writings of various followers of Freud up to the original words of the teacher himself. At the same time, no facts were cited by which it would be possible to judge whether his ideas were fair.

“Freud may have had a great influence on literary criticism,” I tell the professor of English, “but he was not a real scientist. He was not interested in facts. I study psychology by scientific methods.”

“So,” she replies, “you are using a monster of machine intelligence to kill the human in us.”

On both sides of the abyss that separates our views, I hear the same thing: "Science cannot investigate consciousness." Why can't?

Exact and inexact sciences

In the system of scientific hierarchy, "exact" sciences occupy a high position, and "inexact" - low. The subjects studied by the exact sciences are like a cut diamond, which has a strictly defined shape, and all parameters can be measured with high accuracy. "Inexact" sciences study objects that look like an ice cream ball, the shape of which is far from being so definite, and the parameters can change from measurement to measurement. The exact sciences, such as physics and chemistry, study tangible objects that can be measured very accurately. For example, the speed of light (in a vacuum) is exactly 299,792,458 meters per second. A phosphorus atom weighs 31 times more than a hydrogen atom. These are very important numbers. Based on the atomic weight of various elements, it is possible to compile a periodic table, which once made it possible to draw the first conclusions about the structure of matter at the subatomic level.

Once biology was not such an exact science as physics and chemistry. This state of affairs changed dramatically after scientists discovered that genes consist of strictly defined sequences of nucleotides in DNA molecules. For example, the sheep prion gene consists of 960 nucleotides and begins like this:

I must admit that in the face of such precision and rigor, psychology looks like a very imprecise science. The most famous number in psychology is 7, the number of things that can be held in working memory at the same time. But even this figure needs to be clarified. George Miller's 1956 paper on this discovery was titled "The Magic Number Seven - Plus or Minus Two." Therefore, the best measurement result obtained by psychologists can vary in one direction or another by almost 30%. The number of items we can hold in working memory varies from time to time and from person to person. In a state of fatigue or anxiety, I will remember fewer numbers. I speak English and therefore can remember more numbers than those who speak Welsh. “What did you expect? says the professor of English. “The human soul cannot be straightened out like a butterfly in a shop window. Each of us is unique.”

This remark is not entirely appropriate. Of course, each of us is unique. But we all have common properties of the psyche. It is these fundamental properties that psychologists are looking for. Chemists had exactly the same problem with the substances they studied before the discovery of chemical

Page 3 of 23

elements in the 18th century. Each substance is unique. Psychology, compared to the "exact" sciences, had little time to find what to measure and figure out how to measure. Psychology as a scientific discipline has only existed for a little over 100 years. I am sure that in time psychologists will find what to measure and develop devices that will help us make these measurements very accurate.

Exact sciences are objective, inexact sciences are subjective

These optimistic words are based on my belief in the unstoppable progress of science. But, unfortunately, in the case of psychology, there are no solid grounds for such optimism. What we are trying to measure is qualitatively different from what is measured in the exact sciences.

In the exact sciences, the results of measurements are objective. They can be checked. “Don't believe that the speed of light is 299,792,458 meters per second? Here's your equipment. Measure yourself!” When we use this measurement equipment, the results will appear on dials, printouts and computer screens where anyone can read them. And psychologists use themselves or their voluntary assistants as measuring instruments. The results of such measurements are subjective. You can't check them.

Here is a simple psychological experiment. I run a program on my computer that shows a field of black dots continuously moving down from the top of the screen to the bottom. I stare at the screen for a minute or two. Then I press "Escape" and the dots stop moving. Objectively, they no longer move. If I put the tip of a pencil on one of them, I can make sure that this point is definitely not moving. But I still have a very strong subjective feeling that the dots are slowly moving up. If at that moment you were to enter my room, you would see fixed points on the screen. I would tell you that it seems to me that the dots are moving up, but how do you check this? After all, their movement occurs only in my head.

A real scientist wants to independently and independently verify the results of measurements reported by others. “Nullius in verba” is the motto of the Royal Society of London: “Do not believe what others tell you, no matter how high their authority may be.” If I followed this principle, I would have to agree that a scientific investigation of your inner world is impossible for me, because for this I have to rely on what you tell me about your inner experience.

For a while, psychologists pretended to be real scientists by only studying behavior—taking objective measurements of things like movements, button presses, reaction times. But behavioral research is by no means enough. Such studies leave out everything that is most interesting in our personal experience. We all know that our inner world is no less real than our life in the material world. Unrequited love brings no less suffering than a burn from touching a hot stove. The work of consciousness can influence the results of physical actions that can be objectively measured. For example, if you imagine that you are playing the piano, the quality of your performance may improve. So why shouldn't I take your word for it that you imagined playing the piano? Now we psychologists have returned to the study of subjective experience: sensations, memories, intentions. But the problem has not gone away: the mental phenomena that we study have a completely different status than the material phenomena that other scientists study. Only from your words can I learn about what is going on in your mind. You press a button to let me know you've seen a red light. Can you tell me what shade that red was. But there is no way I can get into your mind and check for myself how red was the light that you saw.

For my friend Rosalind, each number has a specific position in space, and each day of the week has its own color (see Fig. CV1 in the color inset). But maybe these are just metaphors? I have never experienced anything like it. Why should I believe her when she says that these are her immediate, uncontrollable sensations? Her sensations relate to the phenomena of the inner world, which I can not verify in any way.

Will big science help inexact science?

Exact science becomes "big science" when it starts using very expensive measuring instruments. The science of the brain went big when CT scanners were developed to scan the brain in the last quarter of the 20th century. One such scanner usually costs more than a million pounds. By sheer luck, being in the right place at the right time, I was able to use these devices when they first appeared, in the mid-eighties. The first such devices were based on the long-established principle of fluoroscopy. An x-ray machine can show bones inside your body because bones are much harder (dense) than skin and soft tissues. Similar density differences are observed in the brain. The skull surrounding the brain has a very high density, while the density of the tissues of the brain itself is much less. In the depths of the brain are cavities (ventricles) filled with fluid, they have the lowest density. A breakthrough in this field came with the development of axial computed tomography (ACT) technology and the construction of the ACT scanner. This machine uses X-rays to measure density, then solves a huge number of equations (which requires a powerful computer) and builds a three-dimensional image of the brain (or any other part of the body) reflecting differences in density. Such a device for the first time made it possible to see the internal structure of the brain of a living person - a voluntary participant in the experiment.

A few years later, another method was developed, even better than the previous one - magnetic resonance imaging (MRI). MRI does not use X-rays, but radio waves and a very strong magnetic field. Unlike fluoroscopy, this procedure is not at all dangerous to health. An MRI scanner is much more sensitive to density differences than an ACT scanner. On images of the brain of a living person, obtained with its help, different types of tissues are distinguishable. The quality of such images is not lower than the quality of photographs of the brain, after death, removed from the skull, preserved with chemicals and cut into thin layers.

Rice. item 2. An example of an MRI structural image of the brain and a section of the brain removed from a corpse

Above is a photograph of one of the sections of the brain, removed from the skull after death and cut into thin layers. Below is an image of one of the layers of the brain of a living person, obtained by magnetic resonance imaging (MRI).

Structural tomography of the brain has played a huge role in the development of medicine. Brain injuries from road traffic accidents, strokes, or tumor growth can have a profound effect on behavior. They can lead to severe memory loss or serious personality changes. Before the advent of CT scanners, the only way to find out exactly where an injury occurred was to remove the skull cap and look. Usually this was done after death, but sometimes in a living patient - when a neurosurgical operation was required. Now tomographs allow you to accurately determine the location of the injury. All that is required of the patient is to lie motionless inside the tomograph for 15 minutes.

Rice. item 3. An example of an MRI scan showing brain damage

This patient suffered two strokes in a row, as a result of which the auditory cortex of the right and left hemispheres was destroyed. The injury is clearly visible on the MRI image.

Structural tomography of the brain is both an exact and a big science. Measurements of the structural parameters of the brain, carried out using these methods, can be very accurate and objective. But what do these measurements have to do with the problem of psychology as an "inexact" science?

Measurement of brain activity

It was not structural tomography that helped solve the problem. Progress in this area was provided by functional tomographs, developed a few years after structural ones. These devices allow you to record the energy consumption of brain tissues. Whether we are awake or asleep, the 15 billion nerve cells (neurons) in our brain are constantly sending signals to each other. This consumes a lot of energy. Our brain consumes about 20% of the energy of the entire body, despite the fact that its mass is only about 2% of body weight. The entire brain is permeated with a network of blood vessels, through which energy is transferred in the form of oxygen contained in the blood. The distribution of energy in the brain is very finely tuned, so that more of it flows into those parts of the brain that are most active at the moment. When we use our hearing, the most active parts of our brain are the two lateral regions, which contain neurons that receive signals directly from the ears (see Fig. CV2 in the color inset). When the neurons in these areas are active, more blood flows there. This connection between brain activity and local changes in blood flow has been known to physiologists for more than 100 years, but before the invention of functional tomographs, it was not possible to record such changes. Functional brain imaging scanners (developed on the basis of positron emission tomography (PET) and functional magnetic resonance imaging fMRI) allow you to register such changes in blood supply, indicating which areas of the brain are currently most active.

The biggest disadvantage of such tomographs is the inconvenience that a person experiences when scanning his brain. He has to lie on his back for about an hour, as still as possible. The only thing you can do while inside the scanner is to think, but in the case of fMRI, even thinking is not so easy, because the scanner makes such a noise, as if a jackhammer is working right under your ear. In one of the earliest, groundbreaking studies, using an early model of a positron emission tomograph, subjects were asked to imagine that they were leaving their home and walking through the streets, turning left at every intersection. It turned out that such purely imaginary actions are quite enough to cause the activation of many parts of the brain.

Rice. item 4. The cerebral cortex and its cells

Section of the cerebral cortex under a microscope and layers of nervous tissue visible on the section.

This is where big science comes to the rescue of "inaccurate" psychology. The subject, lying in the tomograph, imagines that he is walking down the street. In fact, he does not move and does not see anything. These events occur only in his head. There is no way I can get into his mind to check if he is really doing what he was asked to do. But with the CT scanner, I can get into his brain. And I can see that when he imagines walking down the street and turning left, there is activity in his brain of a certain nature.

Of course, most tomographic studies of the brain are more objective. For example, a red light is lit in front of the subject's eyes, and he presses buttons while actually moving his fingers. But I (like some of my colleagues) have always been more interested in the side of the brain, associated with purely mental phenomena. We found that when the subject imagines that he is pressing a button, the same areas in his brain are activated that are activated when he actually presses it. If not for the tomograph, we would have absolutely no objective signs by which we could say that the subject imagines that he is pressing the button. We can make sure that there is not the slightest movement of the fingers or muscle contractions. Therefore, we believe that he is following our instruction to imagine that he is pressing a button every time he hears a certain signal. By measuring brain activity, we get objective confirmation of this mental phenomenon. Using a functional tomograph, I could probably tell if you imagine moving your foot or finger. But as of now, I probably won't be able to tell which finger you were thinking about.

Rice. item 5. Parts of the brain and areas of the cortex

Shown at the top are the main parts of the brain. At the bottom, areas (“fields”) of the cerebral cortex according to Brodmann are shown (the cerebellum and brain stem are removed). Brodmann fields are highlighted based on the appearance of cortical areas under a microscope. The numbers assigned to these fields are arbitrary.

Perhaps I should not have done this, but the study of vision. Nancy Canwisher and her group at the Massachusetts Institute of Technology have shown that when we look at a face (anyone), a certain part of the brain is always activated in our brain, and when we look at a house (any one), another part of the brain located nearby is activated. . If you ask the subject to imagine a person or building taken away a few seconds ago, the corresponding areas in his brain are activated. When I lie inside a scanner in Dr. Canwisher's lab, she can tell what I'm thinking (if I'm only thinking of faces or only of houses).

Rice. item 6. Subject lying inside a CT scanner for brain scanning

This solves the problem of psychology as an "inexact" science. Now we have no need to worry about the inaccuracy, the subjectivity of our information about mental phenomena. Instead, we can make accurate, objective measurements of brain activity. Probably, now I will not be ashamed to admit that I am a psychologist.

But back to our party. I can't resist telling everyone about the big science of brain imaging. The head of the department of physics likes this new stage in the development of psychology. After all, it was physics that made it possible. But the English professor is not ready to accept that the study of brain activity can tell us something about the human psyche.

Rice. item 7. Brain scan results during real and imaginary movements

The diagrams above show the brain slices (top and middle) showing the brain activity. The upper slices show the activity observed when the subject moves his right hand, and the lower slices show the activity observed when the subject only imagines that he is moving his right hand.

Rice. item 8. Faces and houses, visible and imagined

The brain (view from below), and its areas associated with the perception of persons and places. The activity of the same area increases both when we see a face and when we only imagine a face. The same applies to the area related to the perception of places.

“Once you thought that we had a camera in our head. Now you think that there is a computer. Even if you manage to look inside this computer, you will still be left with the same battered model. Of course, computers are smarter than cameras. Maybe they are able to recognize faces or collect eggs on a chicken farm with mechanical hands. But they will never be able to generate new ideas and transfer them to other computers. They will never create a computer culture. Such things are beyond the power of the machine mind.”

I'm leaving to fill my glass. I don't get into an argument. I am not a philosopher. I do not hope to convince others that I am right by the force of arguments. I accept only those arguments that are based on practical experience. And I undertake to show how to make the impossible possible.

How can psychic phenomena arise from material phenomena?

Of course, it would be foolish to think that one can limit oneself to measuring brain activity and forget about the psyche. Brain activity can serve as an indicator of mental activity and thus gives us an objective marker of subjective mental experience. But brain activity and mental experience are not the same thing. With the right equipment, I could probably find a neuron in my brain that fires only when I see blue. But, as the professor of English will remind me with pleasure, this activity and the color blue are not the same thing. Tomographic studies of the brain clearly show us the seemingly insurmountable gulf between objective physical matter and subjective psychic experience.

Exact sciences deal with material objects that can directly affect our senses. We see the light. We feel the weight of a piece of iron. Engaging in exact sciences, such as physics, often requires scientists to work hard physically with the materials under study. The best example of such a scientist is Marie Curie, who is said to have had to process several tons of uranium ore to isolate one-tenth of a gram of radium. This

Page 6 of 23

hard physical labor and made it possible to understand the phenomenon of radioactivity, to find medical applications for x-rays, and ultimately to design a computer tomograph. In doing so, of course, we are assisted by special equipment designed to make fine measurements, working with very rare elements such as radium, very small objects, such as nucleotides in a DNA molecule, or very fast processes, such as the propagation of light. But all this special equipment, like magnifying glasses, only artificially enhances the capabilities of our senses. It helps us see what really exists. No such device will allow us to see what is happening in the inner world of another person. The objects of the inner world do not really exist.

And finally at this party there is a meeting that I was most afraid of. This time I am approached by a self-confident young man without a tie, who is probably engaged in molecular genetics.

He is probably a smart person. How can he say such nonsense? He's just mocking me.

It was only very recently that I managed to realize that it was my own stupidity that did not understand him. Of course, I can read other people's minds. And this is available not only to psychologists. We all read each other's minds all the time. Without it, we would not be able to exchange ideas, we would not be able to create a culture! But how does our brain allow us to penetrate into the inner worlds hidden in the minds of other people?

I can look into the depths of the universe with a telescope and observe the activity inside your brain with a tomograph, but I cannot penetrate your consciousness. We all believe that our inner world is not at all the same as the real material world that surrounds us.

And yet, in everyday life, we are as interested in the thoughts of other people as in the objects of the material world. We interact with other people by exchanging thoughts with them, much more than we physically interact with their bodies. By reading this book, you will know my thoughts. And I, in turn, write it in the hope that it will allow me to change the way you think.

How the brain creates our inner world

So, this is the problem of psychologists? Are we trying to explore the inner world of other people and the phenomena of the psyche, while "real" science is concerned with the material world? The material world is qualitatively different from the world of our psyche. The sense organs allow us to make direct contact with the material world. And our inner world belongs only to us. How can another person explore such a world?

In this book, I am going to show that there really is no difference between the inner world of man and the material world. The difference between them is an illusion created by our brain. Everything that we know, both about the material world and about the inner world of other people, we know thanks to the brain. But the connection of our brain with the material world of physical bodies is just as indirect as its connection with the non-material world of ideas. Hiding from us all the unconscious conclusions to which it comes, our brain creates in us the illusion of direct contact with the material world. At the same time, it gives us the illusion that our inner world is separate and belongs only to us. These two illusions give us the feeling that in the world we live in, we are acting as independent agents. At the same time, we can share our experience of perceiving the world around us with other people. Over the millennia, this ability to share experiences has created human culture, which in turn can influence how our brains work.

By overcoming these illusions created by the brain, we can lay the foundation for a science that will explain to us how the brain shapes our consciousness.

“Don't expect me to take your word for it,” says the professor of English. “Give me proof.”

And I promise her that everything I talk about in this book will be convincingly proven by rigorous experimental data. If you would like to review these data yourself, you will find a detailed list of links to all primary sources at the end of the book.

Part one

What is behind the illusions of our brain

1. What a damaged brain can tell us

Perception of the material world

When I was at school, chemistry was given to me worse than all subjects. The only scientific fact I remember from chemistry class is about one trick that can be used in practice. You are given many small containers of white powders, and you must determine which substance is which. Taste them. The sweet tasting substance would be lead acetate. Just don't try too much!

This approach to chemistry is common to many ordinary people. It is usually applied to the contents of those jars that are in the depths of the kitchen cabinet. If you can't tell what it is by looking at it, try it. This is how we get to know the material world. We explore it with our senses.

Rice. 1.1. The retina of the eye, which provides the link between light and brain activity

The retina, located deep in the eye, contains a large number of special neurons (photoreceptors) whose activity changes when light falls on them. Cone photoreceptors are located in the middle of the retina (in the fovea region). There are three types of cones, each of which responds to light of a specific wavelength (red, green, and blue). Around the fovea are photoreceptor rods that react to weak light of any color. All these cells send signals along the optic nerve to the visual cortex.

It follows that if our sense organs are damaged, it is bad for our ability to explore the material world. It is likely that you are nearsighted. If I ask you to take off your glasses and look around, you will not be able to distinguish small objects located just a couple of meters away from you. There is nothing surprising here. It is our sense organs - eyes, ears, tongue and others - that provide a connection between the material world and our consciousness. Our eyes and ears, like a video camera, collect information about the material world and transmit it to consciousness. If the eyes or ears are damaged, this information cannot be transmitted properly. Such damage makes it difficult for us to get to know the outside world.

This problem

Page 7 of 23

becomes even more interesting if we consider how information from the eyes reaches consciousness. Let's forget for a moment the question of how the electrical activity of the eye's photoreceptors translates into our sense of color, and confine ourselves to observing that information from the eyes (as well as ears, tongue, and other senses) enters the brain. It follows that brain damage can also make it difficult to get to know the material world.

Mind and brain

Before we begin to understand how brain damage can affect our perception of the world around us, we need to take a closer look at the connection between our psyche and the brain. This connection must be close. As we learned in the prologue, whenever we imagine a face, a special area in our brain associated with the perception of faces is activated. In this case, knowing about a purely mental experience, we can predict which area of the brain will be activated in this case. As we will soon see, brain injuries can have a profound effect on the psyche. Moreover, knowing exactly where the brain was injured, we can predict how the patient's psyche has changed as a result of this. But this connection between the brain and the psyche is imperfect. This is not a one-to-one relationship. Some changes in brain activity may not affect the psyche in any way.

On the other hand, I am deeply convinced that any changes in the psyche are associated with changes in brain activity. I am convinced of this because I believe that everything that happens in my inner world (mental activity) is caused by brain activity, or at least depends on it.

So, if I'm right in my belief, the sequence of events should look something like this. Light hits the light-sensitive cells (photoreceptors) in our eyes, and they send signals to the brain. The mechanism of this phenomenon is already well known. Then, the activity that occurs in the brain somehow creates a sense of color and shape in our mind. The mechanism of this phenomenon is still completely unknown. But whatever it is, we can conclude that in our minds there can be no knowledge about the world around us that is not represented in the brain in any way. Everything we know about the world, we know thanks to the brain. Therefore, we probably do not need to ask the question: “how do we or our consciousness cognize the world around us? Instead, you need to ask yourself: how does our brain learn about the world around us? By asking about the brain rather than consciousness, we can put aside for a while the question of how knowledge about the world around us gets into our consciousness. Unfortunately this trick doesn't work. To find out what your brain knows about the world around you, I would first ask you the question: “What do you see?” I appeal to your consciousness to find out what is displayed in your brain. As we will see, this method is not always reliable.

When the brain doesn't know

Of all the sensory systems in the brain, we know the most about the visual system. The visible picture of the world is first displayed in neurons located deep in the retina. The resulting image is inverted and mirrored, just like the image that appears inside a camera: the neurons located on the retina at the upper left represent the lower right part of the visual field. The retina sends signals to the primary visual cortex (V1) in the back of the brain through the thalamus (thalamus), a kind of relay station located deep in the brain. The neurons that transmit these signals partially cross over, so that the left side of each eye is displayed in the right hemisphere, and the right side in the left. The "photographic" image in the primary visual cortex is preserved, so that the neurons located in the upper part of the visual cortex of the left hemisphere? display the lower right part of the field of view.

The consequences of damage to the primary visual cortex depend on where exactly the injury occurred. If the upper left part of the visual cortex is damaged, then the patient is unable to see objects located in the lower right part of the visual field. In this part of the visual field, such patients are blind.

Some migraine sufferers occasionally lose sight of part of their visual field because they temporarily lose blood flow to their visual cortex. This symptom usually begins with a small “blind” area in the visual field, which gradually

Page 8 of 23

grows. This area is often surrounded by a shimmering zigzag line called the fortification spectrum.

Rice. 1.2. How signals are transmitted along the nerves from the retina to the visual cortex

The light signal from the left side of the visual field enters the right hemisphere. The brain is shown below.

Before the information from the primary visual cortex is passed on to the brain for the next stage of processing, the resulting image is decomposed into components such as information about shape, color, and movement. These components of visual information are transmitted further to different parts of the brain. In rare cases, brain injuries can affect areas of the brain involved in the processing of only one of these components, while the rest of the areas remain intact. If the area associated with the perception of color (V4) is damaged, a person sees the world as colorless (this syndrome is called achromatopsia, or color blindness). We have all seen black and white films and photographs, so it is not so difficult to imagine the feelings of people suffering from this syndrome. It is much more difficult to imagine the world of a person who has a damaged area associated with the visual perception of movement (V5). Over time, visible objects, such as cars, change their position in the field of view - but at the same time, it does not seem to the person that they are moving (this syndrome is called akinetopsia). This sensation is probably the opposite of the waterfall illusion I mentioned in the prologue. In this illusion, which each of us can experience, objects do not change their position in the field of view, but it seems to us that they are moving.

Rice. 1.3. How damage to the visual cortex affects perception

Damage to the visual cortex causes blindness in certain parts of the visual field. Loss of the entire visual cortex of the right hemisphere causes blindness on the entire left side of the visual field (hemiopia). Loss of a small area in the lower half of the visual cortex of the right hemisphere leads to the appearance of a blind spot in the upper left half of the visual field (scotoma). Loss of the entire lower half of the visual cortex of the right hemisphere causes blindness in the entire upper half of the left side of the visual field (quadrant hemianopia).

Rice. 1.4. Blind spot development in migraine according to Carl Lashley

The symptom begins with the fact that a blind spot appears in the middle of the visual field, which then gradually increases in size.

At the next stage of processing visual information, its components, such as information about the shape and color, are again combined to recognize objects in the field of view. The areas of the brain where this happens are sometimes damaged, while the areas where the previous stages of visual processing take place remain intact. People with these injuries may have trouble recognizing visible objects. They are able to see and describe the various characteristics of an object, but do not understand what it is. This impairment of recognition is called agnosia. With this syndrome, the primary visual information continues to enter the brain, but the person can no longer comprehend it. In one of the varieties of this syndrome, people are not able to recognize faces (this is prosopagnosia, or agnosia for faces). A person understands that he sees a face in front of him, but cannot understand whose it is. In such people, the area associated with the perception of faces, which I talked about in the prologue, is damaged.

Everything seems to be clear with these observations. Brain damage makes it difficult to transmit information about the world that is collected by the senses. The nature of the impact of these damages on our ability to cognize the world around us is determined by the stage of information transfer at which the damage affects. But sometimes our brain can play weird tricks on us.

When the brain knows but doesn't want to say

The dream of every neurophysiologist is to find a person who would have such an unusual view of the world that we would have to radically reconsider our ideas about how the brain works. To find such a person, two things are needed. First, you need luck to meet him (or her). Secondly, we need to be smart enough to understand the importance of what we observe.

“Of course, you always had enough luck and intelligence,” says the professor of English.

Unfortunately no. Once I was very lucky, but I was not smart enough to understand it. As a young man, when I worked at the Institute of Psychiatry in south London, I explored the human mechanisms of learning. I was introduced to a man who suffered from severe memory loss. For a week, he came to my laboratory every day and learned to perform one task that required a certain motor skill. His result gradually improved without deviations from the norm, and the developed skill was retained by him even after a week's break. But at the same time, he had such a severe memory loss that every day he said that he had never met me before and had never performed this task. “How strange,” I thought. But I was interested in the problems of teaching motor skills. This person learned the required skill normally and did not arouse my interest. Of course, many other researchers have been able to appreciate the importance of people with similar symptoms. Such people may not remember anything about what happened to them earlier, even if it was only yesterday. Previously, we assumed that this is due to the fact that the events that occurred are not recorded in the person's brain. But for the person I worked with, the experience clearly had a long-term effect on the brain, because he was able to perform the task more and more successfully day by day. But these long-term changes taking place in the brain did not affect his consciousness. He couldn't remember anything that happened to him yesterday. The existence of such people indicates that our brain may know something about the world around us that is unknown to our consciousness.

Mel Goodale and David Milner did not repeat my mistake when they met the woman known by the initials D.F. They immediately realized the importance of what they were able to observe. D.F. suffered carbon monoxide poisoning from a malfunctioning water heater. This poisoning damaged the part of her brain's visual system associated with the perception of form. She could vaguely perceive light, shadow, and color, but she could not recognize objects because she could not see what shape they were. Goodale and Milner noticed that D.F. seemed to be much better at walking and picking up items around the test site than one would expect, given her near-total blindness. For several years, they conducted a number of experiments with her participation. These experiments confirmed the presence

Page 9 of 23

discrepancies between what she could see and what she could do.

One of the experiments done by Goodale and Milner looked like this. The experimenter held a stick in his hand and asked D.F. how the stick was positioned. She couldn't tell if the wand was horizontal or vertical or at some angle. It seemed that she did not see the wand at all and was just trying to guess its location. The experimenter then asked her to reach out and take hold of the stick with her hand. It worked out fine for her. At the same time, she turned her hand in advance so that it was more convenient to take the wand. At whatever angle the wand was placed, she could grab it with her hand without any problems. This observation shows that the brain of D.F. “knows” at what angle the wand is located, and can use this information by controlling the movements of her hand. But D.F. cannot use this information to understand where the wand is located. Her brain knows something about the world around her that her consciousness does not know.

Rice. 1.5. Unconscious actions

Patient D.F. the part of the brain needed to recognize objects is damaged, while the part of the brain needed to hold objects in the hand remains intact. She does not understand how the “letter” is rotated relative to the slot. But she can turn it the way she wants by pushing it through the slot.

Very few people are known to have exactly the same symptoms as D.F. But there are quite a few people with brain damage in which the brain plays similar jokes. Perhaps the most striking discrepancy occurs in people with blindsight syndrome, which is caused by trauma to the primary visual cortex. As we already know, such injuries lead to the fact that a person ceases to see any part of the visual field. Lawrence Weiskrantz was the first to show that in some people this blind area of the visual field is not completely blind. In one of his experiments, a light spot moves in front of the subject's eyes in the blind part of his field of vision to the right or left, and the subject is asked to say what? He sees. This question strikes him as extraordinarily stupid. He doesn't see anything. Then, instead, he is asked to guess which way the spot moved, to the left or to the right. This question also strikes him as rather stupid, but he is willing to believe that the venerable Oxford professor knows what he is doing. Professor Weiskrantz found that some people are much better at guessing the direction of the spot than if they were just guessing. In one such experiment, the subject answered correctly more than 80% of the time, although he continued to claim that he did not see anything. Thus, if I had a blindsight syndrome, consciousness could tell me that I can’t see anything, while my brain would have some information about the visible world around me and somehow prompt me, helping me “guess” the correct answer . What is this knowledge that my brain has, but I don't?

When the brain is lying

The unknown knowledge of a person with a blindsight syndrome is at least true. But sometimes brain injuries lead to the fact that consciousness receives information about the world around us, which in reality does not correspond at all. A deaf old woman was awakened in the middle of the night by the sound of loud music. She searched the entire apartment looking for the source of these sounds, but she couldn't find it anywhere. She eventually realized that the music was only in her head. Since then, she has almost always heard this non-existent music. Sometimes it was a baritone accompanied by a guitar, and sometimes a choir accompanied by a whole orchestra.

Rice. 1.6. Spontaneous brain activity associated with blindness (Charles Bonnet syndrome) causes visual hallucinations

The nature of these hallucinations depends on which part of the brain is active. The brain is shown below.

Distinct auditory and visual hallucinations occur in about 10% of elderly people suffering from severe forms of hearing or vision loss. Visual hallucinations that occur with Charles Bonnet syndrome are often only multi-colored spots or patterns. People suffering from this syndrome see the finest nets of gold wire, ovals filled with brickwork-like patterns, or fireworks of brightly colored explosions. Sometimes hallucinations take the form of human faces or figures. These faces are usually crooked and ugly, with protruding eyes and teeth. The figures of people described by patients are usually small, wearing hats or costumes from a certain era.

The heads of men and women of the 17th century are visible, with pleasant thick hair. Probably wigs. Everyone looks extremely disapproving. Never smile.

Dominique Ffitch and his colleagues at the Institute of Psychiatry scanned the brains of people suffering from Charles Bonnet syndrome during such hallucinations. Immediately before a person saw someone's faces in front of him, the activity of the area associated with the perception of faces began to increase in him. Similarly, activity in the area associated with the perception of color began to increase just before the subject reported seeing a color spot.

How Brain Activity Creates False Knowledge

Currently, there are already quite a few studies demonstrating that brain activity can create a false experience regarding events taking place in the outside world. One example of such an experience is related to epilepsy. For every 200 people, on average, there is one who suffers from epilepsy. This disease is associated with a disorder of the brain, as a result of which the electrical activity of a large number of neurons gets out of control from time to time, causing a seizure (seizure). In many cases, the development of a seizure is caused by the activation of a certain part of the brain, in which sometimes a small damaged area can be identified. Uncontrolled activation of neurons begins in this area, and then spreads throughout the brain.

Just before a seizure, many epileptics begin to experience a strange sensation known as an "aura." Epileptics quickly remember what form their aura takes, and when this condition occurs, they know that a seizure will soon begin. Different epileptics experience different sensations. For one, it may be the smell of burnt rubber. For others, it's ringing in the ears. The nature of these sensations depends on the location of the area from which the seizure begins.

Approximately 5% of epileptics have a seizure in the visual cortex. Just before the attack, they see simple multi-colored figures, sometimes rotating or sparkling. We can get some idea of what these sensations are like from sketches made by epileptics after a seizure (see Fig. CV3 in color).

Page 10 of 23

insert).

One patient, Katherine Mize, described in detail complex visual hallucinations that she had associated with flu-induced seizures. She experienced hallucinations for weeks after these seizures stopped.

When I closed my eyes during the lecture, shimmering red geometric shapes appeared in front of me against a black background. At first I was scared, but it was so exciting that I kept looking at them in complete amazement. Fantastic images appeared before my closed eyes. Indistinct circles and rectangles merged to form beautiful symmetrical geometric shapes. These figures constantly grew, again and again absorbed each other and grew again. I remember something like an explosion of black dots on the right side of the visual field. These dots, set against a glowing red background, gracefully spread outward from their point of origin. Two flat red rectangles appeared and moved in different directions. A red ball on a stick moved in circles around these rectangles.

Then a flickering and running red wave appeared at the bottom of the field of vision.

Some epileptics have a seizure in the auditory cortex, and before it starts, they hear sounds and voices.

Sometimes during the aura, epileptics experience complex sensations, during which they relive the events of the past:

A girl who had seizures at the age of eleven. [At the beginning of the seizure] sees herself at the age of seven, walking through a grassy field. Suddenly it seems to her that someone is going to attack her from behind and begin to choke her, or hit her on the head, and she is seized with fear. This episode recurred almost unchanged before each seizure and was apparently based on a real event [which happened to her at the age of seven].

These observations suggest that the abnormal neural activity associated with epileptic seizures may lead to a false knowledge of the world around the person. But in order to verify the validity of this conclusion, it is necessary to conduct an appropriate experiment, during which we will control the nervous activity of the brain by directly stimulating its cells.

In some severe forms of epilepsy, the only way to get rid of seizures is to cut out the damaged part of the brain. Before cutting this area, the neurosurgeon must make sure that its removal will not affect any vital function, such as speech. The great Canadian neurosurgeon Wilder Penfield was the first to perform such operations, during which the patient's brain was stimulated with electrical discharges in order to get an idea of the functions of its individual sections. This is done by applying an electrode to the surface of the exposed brain and passing a very weak electrical current through the brain, which causes the activation of neurons located close to the electrode. This procedure is completely painless and can be performed when the patient is fully conscious.

Rice. 1.7. Direct brain stimulation causes the illusion of real sensations

Above is a photograph of a patient prepared for surgery; an incision line is marked above the left ear.

Below is the surface of the brain with numbered labels that mark areas of positive responses to stimulation.

Patients whose brains are stimulated in this way report sensations similar to those experienced before an epileptic seizure. The nature of these sensations depends on which part of the brain is being stimulated at the moment.

Patient 21: “Wait a minute. Looks like the figure on the left. Seems to be male or female. I think it was a woman. She didn't seem to be wearing any clothes. She seemed to be dragging something or running after the van.”

Patient 13: "They're saying something, but I can't make out what it is." When stimulating the neighboring area, he said: “Here, it starts again. It's water, it sounds like a toilet flush or a dog barking. First the sound of the drain, and then the dog barked.” When stimulating the third, neighboring area, he said: “I think I have music in my ears. A girl or a woman sings, but I don't know the tune. It came from a tape recorder or from a receiver.”

Patient 15: When the electrode was applied, she said, “I feel like a lot of people are yelling at me.” After stimulating the neighboring area, she said: “Oh, everyone is yelling at me, let them stop!” She explained: “They were yelling at me for doing something wrong, everyone was yelling.”

These observations confirm that we can create false knowledge about the world around us by directly stimulating certain areas of the brain. But all of these patients had brain damage. Will the same be observed in healthy people?

How to make our brain deceive us

Do not stick electrodes into the human brain unless absolutely necessary. However, at all times and in all cultures, many people have felt the need to stimulate their brain with various substances. During such stimulations, our brain informs us not about the “real” world around us, but about some other world, which, according to many, is better than ours. Like any other student in the sixties, I read Aldous Huxley's book on hallucinogenic drugs, The Doors of Perception. Perhaps my fascination with this book led me to devote a significant part of my subsequent scientific activity to the study of hallucinations?

Describing the action of mescaline, Huxley wrote: "That's how you should see what things really are." When he closed his eyes, his field of vision was filled with “brightly colored, constantly

Page 11 of 23

changing structures. Huxley also quotes Weir Mitchell's more detailed description of the action of mescaline:

Upon entering this world, he saw many "stellar points" and what looked like "shards of colored glass." Then there were “gentle floating films of color”. They were replaced by a “harsh rush of countless dots of white light” that swept across the field of view. Then came zigzag lines of bright colors, which somehow turned into swollen clouds of even brighter hues. There were buildings, then landscapes. There was a gothic tower of bizarre construction, with dilapidated statues in doorways or on stone pillars. “As I watched, every protruding corner, cornice, and even the faces of the stones at the joints began to gradually be covered or humiliated with clusters of what seemed to be huge gems, but the stones were unworked, so that some looked like masses of transparent fruits ...”

The action of LSD can be very similar.

Now, little by little, I began to enjoy the unprecedented colors and play of shapes that continued to exist before my closed eyes. A kaleidoscope of fantastic images washed over me; alternating, motley, they diverged and converged in circles and spirals, exploded in fountains of color, mixed and turned into each other in a continuous stream.

When the eyes are open, the face of the “real” world is strangely altered.

The world around me is now even more terrifyingly transformed. Everything in the room was spinning, and familiar things and pieces of furniture took on a grotesque menacing shape. They were all in constant motion, as if possessed by inner restlessness.

Rice. 1.8. Effects that psychotropic drugs may have on visual experience

I saw that various folds and waves were moving all over the surface of my blanket, as if snakes were crawling under it. I couldn't follow the individual waves, but I could clearly see them moving across the blanket. Suddenly, all these waves began to gather together in one section of the blanket.

Verification of experience for compliance with reality

I must conclude that if my brain is damaged or disturbed by electrical stimulation or psychotropic drugs, then I should be very careful in trusting the information that my mind receives about the world around me. Some of this information will no longer be available to me. Some will receive my brain, but I will not know anything about it. Even worse, some of the information I receive may turn out to be false and have nothing to do with the real-life material world.

When faced with such a problem, my main task should be to learn to distinguish between true sensations and false ones. Sometimes it's simple. If I see something when my eyes are closed, then these are visions, and not components of the material world. If I hear voices when I'm alone in a room with good soundproofing, then these voices are most likely only in my head. I must not trust such sensations, because I know that my senses need to contact the outside world in order to collect information about it.

Sometimes I can understand that I should not trust my feelings if they are too fantastic to be true. If I see a woman a few inches tall, dressed in a 17th century dress and pushing a baby carriage, it is clearly a hallucination. If I see hedgehogs and some small brown rodents walking on the ceiling above my head, I understand that this is a hallucination. I understand that I should not believe such sensations, because in the real world this does not happen.

But how do I know that my feelings are false if they are perfectly plausible? That deaf old woman, who first heard loud music, at first thought that the music was really coming from somewhere, and looked for its source in her apartment. Only after she could not find anything did she come to the conclusion that this music sounds only in her head. If she lived in an apartment with thin walls and suffered from noisy neighbors, she might conclude, and quite logically, that they turned the radio back on full volume.

How do we know what is real and what is not?

Sometimes a person can be absolutely sure of the reality of their sensations, which are actually false.

A great many terrible and frightening visions and voices haunted me, and although (in my opinion) they had no reality in themselves, yet they seemed to me to be so and made exactly the same impression on me as if they really were what they seemed to be. .

The passage quoted is taken from The Life of the Rev. Mr. George Tross. This book was written by George Tross himself and published by his order in 1714, shortly after his death. The described impressions were experienced by him much earlier, when he was in his early 20s. Remembering them later, Mr. Tross understood that these voices did not really exist, but at the time when he suffered from this illness, he was completely sure of their reality.

I heard a voice, I thought, right behind me, saying More Humility... More Humility... quite a long time. In agreement with him, then I took off my stockings, then my trousers, then my camisole, and while I was undressing like this, I had a strong inner feeling that I was doing everything right and in full accordance with the intention of the voice.

Today, a person who talks about such experiences would be diagnosed with schizophrenia. We still have not been able to figure out what the cause of this disease is. But what is striking is that schizophrenics, experiencing such false sensations, firmly believe in their reality. They go to great lengths of intellectual effort to explain how such apparently impossible things

Page 12 of 23

may actually exist.

In the 40s of the XX century, Percy King was sure that he was being pursued on the streets of New York by a group of young people.

I couldn't see them anywhere. I heard one of them, a woman, say: “You can’t get away from us: we will watch for you and sooner or later we will get to you!” The riddle was aggravated by the fact that one of these "persecutors" repeated my thoughts aloud verbatim. I tried to get away from them like before, but this time I tried to do it with the subway, running in and out of stations, jumping in and out of trains, until 1:00 am. But at every station where I got off the train, I heard their voices closer than ever. I wondered: how could so many pursuers chase me so quickly without being seen by me?

Not believing in either the devil or God, King found an explanation for his experience related to modern technology.

Maybe they were ghosts? Or is it that I developed the ability of a medium? No! Among these persecutors, as I later gradually discovered by deduction, were evidently several brothers and sisters who had inherited from one of their parents some amazing, unprecedented, absolutely unthinkable occult abilities. Believe it or not, some of them not only could read other people's minds, but they could also transmit their magnetic voices - commonly referred to here as "radio voices" - over several miles without raising their voices or making any noticeable effort, and their voices sounded at this distance as if they were heard from the headphones of a radio receiver, and this was done without the use of electrical devices. This unique occult ability to transmit their "radio voices" over such great distances seems to be provided by their natural, bodily electricity, which they have many times greater than that of normal people. Perhaps the iron in their red blood cells is magnetized. The vibrations of their vocal cords apparently generate wireless waves, and these vocal radio waves are picked up by the human ear without being rectified. As a result, combined with their telepathic abilities, they are able to carry on a conversation with another person's unspoken thoughts and then, through so-called "radio voices", respond to those thoughts aloud so that that person can hear them. These persecutors are also capable of transmitting their magnetic voices through plumbing pipes, using them as electrical conductors, speaking while pressed against the pipe, so that the speaker's voice seems to come from the water flowing from the faucet connected to this pipe. One of them is able to make his voice rumble through large water mains for miles - a truly amazing phenomenon. Most people are hesitant to talk about such things to their accomplices, lest they be mistaken for lunatics.

Unfortunately, King himself was not ready to follow his own advice. He knew that "people who have auditory hallucinations hear imaginary things." But he was convinced that the voices he himself heard were real and not the product of hallucinations. He believed that he had discovered “the greatest observed psychological phenomena” and told others about it. But for all the ingenuity with which he explained the reality of these voices, he failed to convince the psychiatrists that he was right. He was kept in a psychiatric hospital.

King and many people like him are convinced that their feelings do not deceive them. If what they feel seems incredible or impossible, they are ready to change their ideas about the world around them rather than deny reality to their sensations.

But the hallucinations associated with schizophrenia have one very interesting feature. These are not just false sensations concerning the material world. Schizophrenics don't just see some colors and hear some sounds. Their hallucinations themselves relate to the phenomena of the psyche. They hear voices that comment on their actions, give advice and give orders. Our brains are capable of forming false inner worlds of other people.

So, if something happens to my brain, my perception of the world can no longer be taken at face value. The brain can create distinct sensations that have nothing to do with reality. These sensations reflect things that do not exist, but one can be quite sure that they exist.

“Yes, but my brain is fine,” says the English professor. “I know what is true and what is not.”

This chapter shows that a damaged brain not only makes it difficult to perceive the world around us. It can also create a sense of perception of something that is not really there. But we should not turn up our noses either. As we will see in the next chapter, even if our brain is healthy and working perfectly, it can still tell us lies about the world around us.

2. What a healthy brain tells us about the world

Even if all our senses are in order and the brain is working normally, we still do not have direct access to the material world. It may seem to us that we directly perceive the world around us, but this is an illusion created by our brain.

Illusion of completeness of perception

Imagine that I blindfolded you and led you into an unfamiliar room. Then I remove the bandage from your eyes, and you look around. Even in that unusual case, if there is an elephant in one corner of the room and a sewing machine in the other, you will immediately get an idea of \u200b\u200bwhat is in this room. You don't have to think or make any effort to get this idea.

In the first half of the 19th century, the human ability to easily and quickly perceive the world around us was in full agreement with the ideas of that time about the work of the brain. It was already known that the nervous system consists of nerve fibers through which electrical signals are transmitted. It was known that electrical energy can be transferred very quickly (at the speed of light), and

Page 13 of 23

therefore, our perception of the world around us with the help of nerve fibers coming from our eyes could well be almost instantaneous. The professor under whom Hermann Helmholtz studied told him that it was impossible to measure the speed of signal propagation along the nerves. It was believed that this speed is too high. But Helmholtz, as befits a good student, ignored this advice. In 1852, he was able to measure the speed of propagation of nerve signals and show that this speed is relatively low. Through the processes of sensory neurons, a nerve impulse propagates 1 meter in about 20 milliseconds. Helmholtz also measured "time of perception": he asked subjects to press a button as soon as they felt a touch on a particular part of the body. It turned out that it takes even more time, more than 100 milliseconds. These observations showed that we do not perceive the objects of the surrounding world instantly. Helmholtz realized that before any object of the surrounding world is displayed in the mind, a number of processes must go through in the brain. He put forward the idea that our perception of the world around us is not directly, but depends on "unconscious inferences." In other words, before we perceive any object, the brain must conclude what it might be for the object, based on the information coming from the senses.

Not only does it seem to us that we perceive the world instantly and effortlessly, it also seems to us that we see the entire field of vision clearly and in detail. This is also an illusion. We see in detail and in color only the central part of the visual field, the light from which enters the center of the retina. This is due to the fact that only in the center of the retina (in the fovea region) are densely packed light-sensitive neurons (cones). At an angle of about 10° from the center, the light-sensitive neurons (rods) are no longer so closely spaced and only distinguish color and shadow. At the edges of the field of view, we see the world blurry and colorless.

Normally, we are not aware of this blurring of our visual field. Our eyes are in constant motion, so that any part of the field of view can be in the center, where it will be visible in detail. But even when we think we have examined everything in sight, we are still in the grip of an illusion. In 1997, Ron Rensink and his colleagues described “change blindness” and since then this phenomenon has become a favorite subject for demonstrations at open houses for everyone involved in cognitive psychology.

Rice. 2.1. In our field of view, everything except the central area is blurry.

Above is the apparent visible image.

Below is the actual visible image.

The problem with psychologists is that every person knows something about the subject of our science from personal experience. It would never occur to me to explain to someone who is into molecular genetics or nuclear physics how to interpret their data, but they are quite happy to explain to me how to interpret mine. Change blindness is so appealing to us psychologists because it can show people that their experiences are deceptive. We know something about their consciousness that they themselves do not know.

The professor of English has come to our department's open day and is heroically trying not to show that she is bored. I demonstrate to her the phenomenon of blindness to change.

The demonstration includes two versions of a complex picture, between which there is one difference. In this case, it is a photograph of a military transport aircraft standing on the runway at the airport. In one version, the aircraft is missing one engine. It is located in the very center of the picture and takes up a lot of space. I show these pictures one after another on a computer screen (and, and this is important, I show a uniform gray screen in between). The English professor sees no difference. After a minute, I show the difference on the screen, and it becomes painfully obvious.

“Quite funny. But where is the science in this?

This demonstration shows that we are quickly grasping the essence of the observed picture: a military transport aircraft on a runway. But in fact, we do not keep in mind all its details. In order for the subject to notice a change in one of these details, I must draw his attention to it (“Look at the engine!”). Otherwise, he will not be able to find the changing detail until he accidentally looks at it at the moment when the picture changes. This is how change blindness arises in this psychological focus. You don't know exactly where the change is happening, and so you don't notice it.

In real life, our peripheral vision, although it gives us a blurry picture of the world, is very sensitive to changes. If the brain detects movement at the edge of the visual field, the eyes immediately turn to that side, allowing the area to be viewed. But in an experiment demonstrating change blindness, the subject sees a blank gray screen in between the pictures. In this case, the entire visible picture changes greatly, since the surface of the screen was multi-colored, and becomes completely gray.

Rice. 2.2. Blind to change

How quickly can you spot the difference between these two pictures?

So we must come to the conclusion that our sense of instantaneous and complete perception of everything that we have in our field of vision is false. Perception occurs with a slight delay, during which the brain produces “unconscious inferences” that give us an idea of the essence of the observed picture. In addition, many parts of this picture remain blurred and not visible in all details. But our brain knows that what we are seeing is not blurry, and it also knows that eye movements can show any part of the visual field sharply and distinctly at any time. Thus, the detailed visible picture of the world that seems to us reflects only what we can potentially consider in detail, and not what is already displayed in detail in our brain. immediacy

Page 14 of 23

our contact with the material world is sufficient for practical purposes. But this contact depends on our brain, and our brain, even quite healthy, does not always tell us everything it knows.

Our hidden brain

Could it be that in an experience that demonstrates blindness to change, our brain still sees the changes that occur in the picture, despite the fact that they are not visible to consciousness? Until recently, this question was very difficult to answer. Let's step away from the brain for a moment and ask ourselves if we can be affected by something we've seen but aren't aware of. In the sixties, this phenomenon was called subliminal perception, and psychologists strongly doubted its existence. On the one hand, many people believed that advertisers could introduce a hidden message into the film that would make us, for example, buy this or that drink more often, without realizing that we were being manipulated. On the other hand, many psychologists believed that there was no subliminal perception. They argued that in a properly designed experiment, the effect would be observed only if the subjects were aware of what they saw. Since then, many experiments have been carried out and no evidence has been obtained that unconsciously perceived advertising hidden in films can make us buy a drink more often. However, it has been shown that some unconsciously perceived objects can have a small effect on our behavior. But it is difficult to demonstrate this effect. To make sure that the subject is not aware that he saw some object, it is shown very quickly and "masked" it, immediately after that another object is shown in the same place.

The displayed objects are usually words or pictures on a computer screen. If the duration of the demonstration of the first object is short enough, the subject sees only the second object, but if it is too short, then there will be no effect. The first object must be shown for a strictly defined time. How to measure the impact of objects that the subject sees, but does not realize it? If you ask the subject to guess some properties of an object that he has not seen, such a request will seem strange to him. He will try his best to see the flashing image for a moment. After a number of attempts, this may work.

The whole point is that the result of the impact is preserved after the demonstration of the object. Whether this result can be tracked depends on the questions asked. Robert Zajonc showed subjects a series of unfamiliar faces, each masked by a tangle of lines so that the subjects were unaware they were seeing faces. Then he showed each of these faces again, next to another, new face. When he asked, “Guess which of these faces I just showed you?” - the subjects guessed no more often than they were wrong. But when he asked, “Which of these faces do you like best?” - they more often chose exactly the face that they had just seen unconsciously.

Rice. 2.3. Image masking

Two faces are shown on the screen, one after the other. If the interval between the first face and the second is less than approximately 40 milliseconds, the subject is unaware that he has seen the first face.

When brain-scanning CT scanners became available, researchers were able to ask a slightly different question about subthreshold perception: “Does an object cause changes in our brain activity, even if we are not aware that we are seeing it?” This question is much easier to answer because it does not require the subject to give any answers about objects he has not seen. It's enough just to watch his brain. Paul Whalen and his colleagues used a frightened face as such an object.

John Morris and his colleagues had previously established that showing a person images of faces with a frightened expression (as opposed to a happy or calm one) increased activity in the amygdala, a small area of the brain that seems to be associated with monitoring dangerous situations. Whalen and his colleagues conducted similar experiments, but this time images of frightened faces were perceived only at a subthreshold level. In some cases, the subjects immediately after the frightened face were shown a calm one. In other cases, a calm face was preceded by a joyful one. In both cases, people said they saw only a calm face. But when a calm face was preceded by a frightened one, there was an increase in activity in the amygdala, despite the fact that the subject was not aware that he was seeing a frightened face.

Rice. 2.4. Our brain reacts to scary things we've seen without realizing it.

Diana Beck and her colleagues also used faces as subjects, but they based their experiments on demonstrating change blindness. In some cases, the face of one person was replaced by the face of another. In other cases, the face remained the same. The experiment was set up in such a way that the subjects noticed changes in only about half of the cases when these changes occurred. The subjects did not feel any difference between the cases when there were no changes and when there were changes that they did not notice. But their brains felt the difference. In cases where the image of the face changed to another, there was an increase in activity in the area of the brain associated with the perception of faces.

So, our brain does not tell us everything it knows. But he is not capable of such a thing: sometimes he actively misleads us ...

Rice. 2.5. Our brain reacts to changes we see but are not aware of.

Sources: Redrawn from: Beck, D.M., Rees, G., Frith, C.D., & Lavie, N. (2001). Neural correlates of change detection and change blindness. Nature Neuroscience, 4(6), 645–656.

Our inadequate brain

Before the discovery of change blindness, the favorite focus of psychologists was visual illusions (deceptions of the eye). They also make it easy to demonstrate that we do not always see what is actually there. Most of these illusions are known to psychologists for more than

Page 15 of 23

hundred years, and for artists and architects much longer.

Here is one simple example: Hering's illusion.

Rice. 2.6. Goering's illusion

Even if we know that the two horizontal lines are actually straight, they appear to us to be arcuately curved. Ewald Göring, 1861

Horizontal lines appear distinctly curved. But if you put a ruler on them, you will see that they are absolutely straight. There are many other similar illusions in which straight lines appear to be curved or objects of the same size appear to be different sizes. In Hering's illusion, the background that the lines run through somehow prevents us from seeing them for what they really are. Examples of such a distorted perception can be found not only in the pages of psychology textbooks. They are also found in the objects of the material world. The most famous example is the Parthenon in Athens. The beauty of this building lies in the ideal proportions and symmetry of the straight and parallel lines of its outlines. But in reality, these lines are neither straight nor parallel. The architects introduced curves and distortions into the proportions of the Parthenon, calculated so that the building looked straight and strictly symmetrical.

To me, the most striking thing about these illusions is that my brain continues to give me false information even when I know that this information is false, and even when I know what these objects really look like. I can't bring myself to see the lines in Hering's illusion as straight. “Amendments” to the proportions of the Parthenon still work, after more than two thousand years.

The Ames Room is an even more striking example of how little our knowledge can influence our vision of the world around us.

I know that all these people are actually the same height. The one on the left seems small because it is further away from us. The room is not really rectangular. The left edge of the back wall is much further away from us than the right edge. The proportions of the windows in the back wall are distorted so that they appear rectangular (like the Parthenon). And yet my brain prefers to perceive it as a rectangular room containing three people of impossibly different heights than as an oddly shaped room that someone has built, containing three people of normal height.

Rice. 2.7. The perfection of the appearance of the Parthenon is the result of an optical illusion

Schemes based on the findings of John Pennethorne (Pennethorne, 1844); deviations are greatly exaggerated.

There is at least one thing to be said to justify my brain. The appearance of the Ames room is indeed ambiguous. What we see is either three unusual people in an ordinary rectangular room, or three normal people in a strangely shaped room. The interpretation of this picture that my brain chooses may not be plausible, but it is at least a possible interpretation.

“But there is no single correct interpretation and cannot be!” says the professor of English.

I object that although our information is ambiguous, this does not mean that there can be no correct interpretation at all. And one more thing: our brain hides this possibility of a double interpretation from us and gives us only one of the possible interpretations.

Moreover, sometimes our brain does not take into account the available information about the world around us at all.

Rice. 2.8. Ames room

A 1946 invention by Adelbert Ames, Jr. based on an idea by Helmholtz.

All three people are actually the same height, but the proportions of the room are distorted.

Sources: Wittreich, W.J. (1959). Visual perception and personality, Scientific American, 200(4), 56–60(58). Photo courtesy of William Vandivert.

Our creative brain

Confusion of feelings

I know a few people who look completely normal. But they see a world different from the one I see.

As a synesthete, I live in a different world than those around me, in a world where there are more colors, shapes and sensations. In my universe, the ones are black and the environments are green, the numbers go up into the sky, and every year is like a roller coaster.

Most of us have different feelings completely separate from each other. Light waves enter our eyes and we see colors and shapes. Sound waves enter our ears and we hear words or music. But some people, called synesthetes, not only hear sounds when sound waves hit their ears, but they also experience colors. D.S., when she hears music, sees various objects in front of her: falling golden balls, flickering lines, silvery waves, like on an oscilloscope screen, which float in front of her six inches from her nose. The most common form of synesthesia is color hearing.

Every word you hear evokes a sensation of color. In most cases, this color is determined by the first letter of the word. For each synesthete, any letter and any number has its own color, and these colors remain unchanged throughout life (see Fig. 1 in the color insert). Synesthetes do not like it if the depicted letter or number is painted in the “wrong” color. For the synesthete, known by the initials G.S., the three is red and the four is cornflower blue. Carol Mills showed G.S. a series of multi-colored numbers and asked her to name their colors as quickly as possible. When the subject was shown a number of the “wrong” color (for example, a blue three), she needed more time to answer. The synesthetic color that this figure had for her interfered with the perception of her real color. This experiment gives us objective evidence that the sensations described by synesthetes are no less real than the sensations of other people. He also shows that these sensations come whether the person wants it or not. extreme forms

Page 16 of 23

synesthesia can interfere with a person's life, making it difficult to perceive words.

The late S.M. had such a voice. Eisenstein, as if some kind of flame with veins was approaching me.

Or, on the contrary, they can help.

From time to time, when I was not sure how to spell a particular word, I thought about what color it should be, and this helped me figure it out. In my opinion, this technique has helped me more than once to write correctly, both in English and in foreign languages.

Synesthetes know that the colors they see are not really there, but despite this, their brain creates a vivid and distinct sensation that they are. “And why do you say that these flowers do not really exist? asks the professor of English. - Are colors phenomena of the material world or our consciousness? If consciousness, then how is your world better than the world of your acquaintance with synesthesia?

When my friend says that these colors do not really exist, she must mean that most other people, including myself, do not feel them.

Sleeper hallucinations

Synesthesia is quite rare. But each of us has had dreams. Every night while we sleep, we experience distinct sensations and strong emotions.

I dreamed that I needed to enter the room, but I did not have the key. I went to the house, and Charles R. was standing there. The thing is, I was trying to climb in the window. Anyway, Charles was standing there at the door, and he gave me sandwiches, two sandwiches. They were red - I think with raw smoked ham, and he had boiled pork. I didn't understand why he gave me the worse ones. Anyway, after that he entered the room, and something was not right there. Looks like there was some sort of party going on. I guess that's when I began to think about how quickly I could get out of there, if necessary. And there was something to do with nitroglycerin, I don't really remember. The last thing I remember is someone throwing a baseball.

Despite the fact that the sensations experienced in a dream are so distinct, we remember only a small part of them (about 5%).

“But how do you know that I have so many dreams, even if I myself cannot remember them?” asks the professor of English.

In the 1950s, Eugene Aserinsky and Nathaniel Kleitman discovered a special phase of sleep during which rapid eye movement occurs. Different phases of sleep are associated with different forms of brain activity, which can be measured using the EEG. During one of these phases, our brain activity on the EEG looks exactly the same as during wakefulness. But at the same time, all our muscles are, in fact, paralyzed, and we cannot move. The only exception is the muscles of the eyes. During this phase of sleep, the eyes move rapidly from side to side, despite the fact that the eyelids remain closed. This is the so-called phase of REM sleep, or REM phase (rapid eye movement phase). If I wake you up during REM sleep, you will most likely (with a 90% chance) say that you were watching a dream when you were awakened, and you will be able to remember many details of this dream. However, if I wake you up five minutes after the end of REM sleep, you will not remember any dreams. These experiments show how quickly dreams are erased from our memory. We remember them only when we wake up during or immediately after REM sleep. But I can tell you're dreaming by monitoring your eye movements and your brain activity while you sleep.

Wakefulness: fast, asynchronous nerve activity, muscle activity, eye movement

Non-REM sleep: slow, synchronous nerve activity, some muscle activity, no eye movement, few dreams

REM sleep: REM, non-synchronous neural activity, paralysis, no muscle activity, rapid eye movement, many dreams

The pictures that the brain shows us during dreams do not reflect the objects of the material world. But we perceive them so clearly that some people have wondered if they are accessing some other reality in their dreams. Twenty-four centuries ago Chuang Tzu had a dream in which he was a butterfly. “I dreamed that I was a butterfly fluttering from flower to flower and knowing nothing about Chuang Tzu.” Waking up, he, according to him, did not know who he was - a man who dreamed that he was a butterfly, or a butterfly who dreamed that she was a man.

Robert Frost's dream about the apples he just picked

... And I comprehended

What a vision the soul languished.

All apples are huge and round,

flickered around me

A pink blush from the mist,

And the shin and foot ached

From stairs, rungs.

Suddenly I shook the stairs sharply ...

(Excerpt from the poem “After picking apples”, 1914)

Usually the content of our dreams is implausible enough for us to confuse the dream with reality (see figure 4 in color inset). For example, there are often inconsistencies between the appearance of people we see in a dream and their real prototypes. “I was talking to my colleague (in my dream), but she looked different, much younger, like one of the girls I went to school with, about thirteen years old.” However, during sleep, we are convinced that everything that happens to us is actually happening. And only at the moment of awakening do we realize, usually with relief, that “it was only a dream. I don't have to run away from anyone."

Hallucinations in healthy people

Synesthetes are unusual people. When we dream, our brain is also in an unusual state. To what extent the brain of an ordinary, physically healthy person in the waking state is able to create something

Page 17 of 23

similar? It was this question that was devoted to a large-scale study, which involved 17,000 people, conducted at the end of the 19th century by the Society for Psychical Research. The main goal of this society was to find evidence for the existence of telepathy, that is, the transmission of thoughts directly from one person to another without any obvious material intermediaries. It was believed that such a transmission of thoughts at a distance is especially likely in a state of strong emotional stress.

On October 5, 1863, I woke up at five o'clock in the morning. It was at Minto House Normal School in Edinburgh. I distinctly heard the characteristic and well-known voice of one of my close friends, repeating the words of a famous church hymn. Nothing was visible. I lay in bed fully conscious, in good health, and not disturbed by anything in particular. At the same time, almost at the same moment, my friend was suddenly stricken with a fatal illness. He died on the same day, and on the same evening I received a telegram announcing this.

Today, psychologists treat such claims with extreme distrust. But at that time, the Society for Psychical Research included several eminent scientists in its ranks. The chairman of the commission overseeing this "census of hallucinations" was Professor Henry Sidgwick, the Cambridge philosopher and founder of Newham College. The collection of materials was carried out with great care, and a report published in 1894 included the results of a detailed statistical analysis. The compilers of the report tried to exclude from it data on sensations that could be the fruits of dreams or delusions associated with bodily diseases, or hallucinations associated with mental illnesses. They also went to great lengths to draw the line between hallucinations and illusions.

Here is the exact question they asked the respondents:

Have you ever experienced, while fully conscious, the distinct sensation that you are seeing or touching a living being or an inanimate object, or hearing a voice, although this sensation, as far as you could determine, was not due to any external physical influence?

The published report is almost 400 pages long and consists mostly of the actual words of the respondents describing their feelings. Ten percent of the respondents experienced hallucinations, and most of these hallucinations were visual (over 80%). For me, the most interesting cases are those that have no obvious relation to telepathy.

From Mrs. Girdlestone, January 1891

For several months in 1886 and 1887, as I walked down the stairs of our Clifton house in broad daylight, I felt, more than saw, a multitude of animals (mostly cats) passing me and pushing me aside.

Mrs Girdlestone writes:

The hallucinations consisted of hearing my name called so clearly that I turned around to see where the sound was coming from, whether it was a figment of the imagination or a memory of how this happened in the past, this voice, if you can call it that, had a completely inexpressible quality that invariably frightened me and separated it from ordinary sounds. This went on for several years. I have no explanation for these circumstances.

If she were to describe such experiences to her therapist today, he would most likely suggest that she undergo a neurological examination.

I also find interesting cases classified as illusions: their origin was clearly connected with the physical phenomena of the material world.

From Dr. J. J. Stoney

A few years ago, on an unusually dark summer evening, my friend and I rode bicycles—he on a two-wheeler, I on a three-wheeler—from Glendalough to Rathdrum. It was drizzling, we had no streetlights, and the road was obscured by trees standing on either side of it, between which the horizon line was barely visible. I was riding slowly and carefully, about ten or twelve yards ahead of me on the horizon, when my bike went over some tin or something like that on the road and there was a loud bang. My companion immediately drove up and called out to me in extreme anxiety. He saw through the darkness how my bike turned over and I flew out of the saddle. The ringing made him think of the most probable cause of it, and at the same time a visible picture arose in his mind, faint, but in this case sufficient to see it distinctly, when it was not overpowered by objects normally visible to the human eye.

In this example, Dr. Stoney's friend saw an event that didn't actually happen. According to Dr. Stoney, the expected picture created a visual image strong enough in the mind of his friend to see him before his eyes. In terms that I would use, his friend's brain created a plausible interpretation of what happened, and this interpretation he saw as a real event.

From Miss W.

One evening, at dusk, I went into my bedroom to get one thing from the mantelpiece. A slanting beam of light from a lantern fell through the window, which barely made it possible to see the vague outlines of the main pieces of furniture that were in the room. I was carefully feeling around for the thing I had come for, when, turning slightly, I saw behind me, not far from me, the figure of a little old woman, sitting very sedately, with her hands clasped in her lap, and holding a white handkerchief. I was very frightened, because before that I had not seen anyone in the room, and cried out: “Who is there?” -

Page 18 of 23

but no one answered, and when I turned face to face with my guest, she immediately disappeared from view ...

In most stories about ghosts and spirits, the story would end there, but Miss W persisted.

Since I am very nearsighted, at first I thought it was just an optical illusion, so I returned to my search for opportunities in the same position and when I found what I was looking for, I began to turn around to leave, and suddenly - here are the miracles ! - I saw this old woman again, clearly, as never before, with her funny cap and dark dress, with meekly folded hands, clutching a white handkerchief. This time, I quickly turned around and resolutely approached the vision, which disappeared just as suddenly as the last time.

So, the effect was reproducible. What was his reason?

Now, convinced that this is not a hoax, I decided to investigate, as far as possible, the causes and nature of this riddle. Slowly returning and taking up my former position by the fireplace and seeing the same figure again, I slowly turned my head from side to side and noticed that she was doing the same. Then I slowly walked backwards, without changing the position of my head, reached the same place, slowly, turned around - and the riddle was solved.

A small lacquered mahogany bedside table standing near the window, in which I kept various trinkets, seemed to be the body of an old woman, a sheet of paper sticking out of its half-open door played the role of a handkerchief, a vase standing on the bedside table looked like a head in a cap, and an oblique beam of light falling on it , along with a white curtain on the window, completed the illusion. I dismantled and reassembled this figure several times and marveled at how clearly it was visible when all the components occupied exactly the same position in relation to each other.

Miss W.'s brain incorrectly deduced that the set of objects in the dark room was a little old woman sitting sedately by the window. Miss W. doubted this. But notice how much she had to work to figure out this illusion. At first, she doubted that what she was seeing was true. She didn't expect to meet anyone in this room. Sometimes her eyes deceive her. Then she experiments with her perception, looking at this "old woman" from different positions. How easy it is to be deceived by such an illusion! But very often we do not have the opportunity to experiment with our perception, and there is no reason to believe that our sensations are deceptive.

Edgar Allan Poe describes his fear of the "dead head"

At the end of a very hot day, I sat with a book in my hands near an open window overlooking the banks of the river and a distant hill. Looking up from the page, I saw a bare slope, and on it a hideous-looking monster, which quickly descended from the hill and disappeared into the dense forest at its foot.

The size of the monster, which I judged from the trunks of the huge trees through which it moved, was much larger than any of the ocean ships. His mouth was placed at the end of a trunk sixty or seventy feet long, and about the thickness of an elephant's body. At the base of the trunk were tufts of thick black hair, more than on the skins of a dozen buffaloes. On either side of the trunk ran a gigantic horn thirty or forty feet high, prismatic and crystalline, reflecting the rays of the setting sun dazzlingly. The body was wedge-shaped and pointed down. From it came two pairs of wings, each nearly a hundred yards long; they were located one above the other and were completely covered with metal scales. I noticed that the top pair was connected to the bottom thick chain. But the main feature of this terrible creature was the image of a skull, which occupied almost the entire of its chest and brightly whitened on its dark body, as if carefully drawn by an artist. While I was looking at the terrifying animal, the huge jaws, which were located at the end of its trunk, suddenly opened, and from them came a loud and mournful cry, which sounded in my ears with an ominous omen; As soon as the monster disappeared at the bottom of the hill, I fell senseless to the floor.

[The owner of Po's house explains:] Let me read you the description of the genus Sphinx, family Crepuscularia, order Lepidoptera, class Insecta, i.e. insects. Here is the description:

“The Death's Head Sphinx sometimes inspires considerable fear in unenlightened people because of the sad sound it makes and the death emblem on its shield.”

He closed the book and leaned forward to find the exact position I was in when I saw the monster.

- Well, yes, here it is! he exclaimed. “Now it is creeping up, and I must admit it looks unusual. However, it is not as large and not as far away from you as you imagined. I see that it is no more than one sixteenth of an inch long, and the same distance, one sixteenth of an inch, separates it from my pupil.

(Excerpts from the story "The Sphinx", 1850)

This chapter shows that even a normal, healthy brain does not always give us a true picture of the world. Due to the fact that we do not have a direct connection with the material world around us, our brain has to make conclusions about the world based on the raw data received from the eyes, ears and all other senses. These conclusions may be erroneous. Moreover, our brain knows a lot of all sorts of things that do not reach our consciousness at all.

But there is one piece of the material world that we always invariably carry with us. After all, at least we have direct access to information about the state of our own body? Or is this also an illusion created by our brain?

3. What our brain tells us about our body

Privileged access?

My body is an object of the material world. But I have a special relationship with my own body, not the same as with other material objects. In particular, my brain is also part of my body. The processes of sensory neurons lead directly to the brain. Outgrowths of motor neurons lead from the brain to all my muscles. These are very direct connections. I have direct control over everything my body does, and I don't need any inference to understand what state it is in. I have almost instant access to any part of my body at any given time.

So why do I still get a little shock when I see a plump old man in the mirror? Maybe I don't really know much about myself? Or is my memory forever corrupted by vanity?

Where is the border?

My first mistake is the thought that there is a clear difference between my body and the rest of the material world. Here is a little party trick invented by Matthew Botvinick and Jonathan Cohen. You put your left hand on the table and I cover it with a screen. On the same table, I place a rubber hand in front of you so that you can see it. Then I touch both your hand and the rubber hand at the same time with two brushes. You feel your hand being touched and you see a rubber hand being touched. But after a few minutes, you will no longer feel the touch of the brush where it touches your hand. You will feel it where it touches the rubber hand. The sensation will somehow go beyond your body and pass into an object of the world around you separate from you.

Such tricks performed by our brain are not only suitable for parties. In the parietal lobes of the cortex of some monkeys (presumably humans too) there are neurons that are activated when the monkey sees something near its hand. It doesn't matter where her brush is at the same time. Neurons are activated when something is in close proximity to it. Apparently, these neurons indicate the presence of objects that the monkey can reach with his hand. But if you give a monkey a paddle to use, very soon those same neurons will start responding whenever the monkey sees anything near the end of that paddle. For this part of the brain, the shoulder blade becomes like an extension of the monkey's hand. This is how we feel the tools we use. With a little practice, we get the feeling that we control the tool as directly as if it were part of our body. This applies to things as small as a fork and as big as a car.

Rice. 3.2. Monkey and shovel

If a monkey sees anything within range, the activity of certain neurons in its parietal cortex increases. Atsushi Iriki taught monkeys how to use a shovel to get food that was out of reach for their hands. When a monkey uses such a shovel, the parietal lobe neurons respond in exactly the same way to objects located within the reach of a hand armed with a shovel.

We feel ourselves as independent agents, freely interacting with the material world around us. We are aware of ourselves and our actions, because we are in complete control of our actions. We act according to our own understanding and are responsible for our choice. Every act and every decision becomes part of the experience that forms our inner subjective world of ideas and sensations. The world is isolated, belonging exclusively to us. But is it?

The British neuroscientist Chris Frith demonstrates with examples that the inner world of each of us is formed by the brain, and that this very brain hides from us most of the decisions it makes, giving us the illusion of independence. In his book, he shows us that understanding other people is not just a possible thing, but no less natural than the perception of the material world. But first things first.

The first illusion is that we think we are interacting with the outside world directly.

"Our brain gives us the illusion of direct contact with the material world." This, according to Chris Frith, is the first illusion to be overcome.

Material objects and phenomena affect our senses directly. We feel the rough surface, hear the sound, feel the taste of food. However, as it turned out, the direct impact of material objects on our sense organs does not yet mean our direct perception of the surrounding world. What comes from the senses to our brain are only signals. By converting them into separate ready-made models, the brain creates images of the outside world, which become our representations of reality. How objective are these views? Hard to say. In this case, something else is more important to us: we perceive not the world itself, but its models created by our brain. Take, for example, our vision: "the visual image that arises in the retina of our eyes is two-dimensional, and yet the brain gives us a distinct sense of the world, consisting of objects distributed in three-dimensional space" .

The feeling of immediacy of perception of the world is reinforced by another important component, namely the ease with which we receive information about the world. Instantaneous perception is also the result of brain activity. We simply do not notice all the work done that precedes the creation of this image.

So it turns out that we perceive not the world, but its model. And although the model of the world is not the world itself, for us, in fact, it is one and the same. As Chris Frith writes in his book: “You can say that our sensations are fantasies that coincide with reality.”

The second illusion - we believe that our inner world is separate from the outer and belongs only to us

Unlike the external world, the perception of which is not a problem for us, it is more and more difficult with the inner world of other people. The subjective world of representations cannot be studied using natural scientific methods. We can measure the speed of movement of a material object, even one that we cannot see with the naked eye. However, it is not possible to make such measurements with mental processes. Does this mean that the inner world of a single person will remain a secret for us with seven seals?

Not necessarily. The impossibility of revealing the essence of the inner world using the above methods only means that these methods are not suitable for this particular area. Then how can one comprehend the inner subjective world?

It was already mentioned earlier that we do not have direct access to the material world. The brain is constantly building models of the world around us. “Our knowledge of the inner world of other people can arise in exactly the same way. The signals coming from our senses allow the brain to create a model of the non-material world of ideas, desires and intentions.

In other words, the same techniques of the brain that allow us to perceive the material world give us the opportunity to comprehend the inner subjective world of another person.

A good example is the explanation given by Chris Frith:

When I look at a tree in a garden, I don't have a tree in my mind. In my mind there is only a model of this tree created by my brain (or an idea about it). This model is built using a series of assumptions and predictions. In the same way, when I try to tell you something, your thought cannot be in my mind, but my brain, through assumptions and predictions, can create a model of your thought (an idea of \u200b\u200bit in my mind). Now I have two things in my mind: 1) my own thought and 2) my model of your thought. I can directly compare them. If they are similar, then I probably managed to communicate my idea to you. If they are different, then I clearly failed.

There is really no difference between the inner world of a person and the material world

We experience the outer world in a completely different way than our inner world, not to mention the subjective world of another person. When we look around, we see the world around us and ourselves in it. However, Chris Frith explains this feeling by citing Helmholtz's developments in the book, in which the German scientist explains that the brain gives us a feeling of a static world, although with every eye movement we should see the opposite.

How does he create this feeling? The brain has information about when and where our eyes will be turned. Knowing the trajectory of eye movement even before this very movement, our brain determines exactly how the space we see will change. With this information, predicting our next move, he paints a complete picture of what we see. So the brain generates a sense of the stillness of the world.

Our separation from him is also illusory. In fact, our brain integrates us not only into the material world, but also into the inner world of other people. Our knowledge of the world through images allows us to create similar images of the inner world of other people, which gives us the opportunity to influence their behavior. Moreover, our own inner world is largely determined by the people with whom we interact, they also influence our actions and thoughts.

Conclusion

Chris Frith writes about how the brain shapes our consciousness and influences our perception of the world and ourselves in it. This book will not provide answers to such questions as "What is consciousness?", "What is I?", "Is there free will?" and others. She wasn't designed for that. In it, the neuropsychologist, summarizing numerous experiments and experiments conducted both by himself and his colleagues, is trying to change our traditional ideas, which later, according to the author, will allow us to lay "the foundation of a science that will explain to us how the brain forms our consciousness" .

Literature:

1. Brain and Soul: How Nervous Activity Shapes Our Inner World / Chris Frith; per. from English. P. Petrov. - M: Astrel: CORPUS, 2010. - 335 p.
2. Chris Frith https://sites.google.com/site/chrisdfrith/Home

Editor: Chekardina Elizaveta Yurievna

Chris Frith
Brain and soul
How physiology shapes our inner world
(Christopher Donald Frith.
Making up the mind. How the brain creates our mental world)

Corpus, 2010
Series: Elements
Pages: 288, hardcover, 145х217
ISBN: 978-5-271-28988-0. Circulation: 4000.
Translation from English by Peter Petrov.

The famous British neurophysiologist Chris Frith is well known for his ability to talk simply about very complex problems of psychology - such as mental activity, social behavior, autism and schizophrenia. It is in this area, along with the study of how we perceive the world around us, act, make choices, remember and feel, that today there is a scientific revolution associated with the introduction of neuroimaging methods. In Brain and Soul, Chris Frith talks about all this in the most accessible and entertaining way.

Chapter 5

The kind of learning discovered by Pavlov and Thorndike serves us well, but it works very crudely. Everything in the world around us is divided into only two categories: pleasant and unpleasant. But we perceive the world not in such rough categories. When I look at the garden outside my window, I immediately see such a wealth of various colors and shapes that it seems like a hopeless undertaking to try to convey this feeling in its entirety to anyone else. But at the same time that I experience all these colors and shapes, I also see them as objects that I can recognize and name: freshly cut grass, primroses, old brick posts and, at this particular moment, a magnificent green woodpecker with bright - a red cap. These sensations and recognitions go far beyond the simple categories of pleasant and unpleasant. How does our brain discover what is in the world around us? How does our brain know what makes us feel?

Our brain creates a feeling of lightness in our perception

A remarkable feature of our perception of the material world in all its beauty and in all its details is that it seems to us so easy. According to our feelings, the perception of the world around us is not a problem. But this feeling of lightness and instantaneity of our perception is an illusion created by our brain. And we didn't know about this illusion until we tried to make machines capable of perception.

The only way to know whether it is easy or difficult for our brain to perceive the world around us is to make an artificial brain capable of perceiving the environment. To make such a brain, you need to establish what components it should consist of, and find out what functions these components should perform.

Information revolution

The main components of the brain were discovered by neurophysiologists at the end of the 19th century. The fine structure of the brain was established by examining thin sections of brain tissue under a microscope. These sections were stained differently to show different aspects of brain structure. Research has shown that the brain contains many nerve cells and a very complex network of interconnected fibers. But the main discovery in the field of studying the main components of the brain was made by the neuroanatomist Santiago Ramón y Cajal. Through detailed studies, he showed that the fibers of this network grow from nerve cells and, most importantly, there are gaps in this network. A fiber growing from one cell comes very close to the next cell, but does not merge with it. These gaps are the synapses described in the previous chapter (see Figure 4.3). From the results of his research, Ramon y Cajal concluded that the main element of the brain is a neuron, that is, a nerve cell, with all its fibers and other processes. This concept was widely accepted and became known as the "neural doctrine".

Rice. 4.3. Synapse. Location of signal transmission from one nerve cell to another
1. A nerve impulse (action potential) reaches the presynaptic membrane at the end of one cell.
2. Because of this, the vesicles swim up to the membrane and release the neurotransmitter contained in them into the synaptic cleft.
3. Neurotransmitter molecules reach receptors located on the postsynaptic membrane belonging to the second cell. If it's an excitatory synapse and the signal is strong enough, it could trigger a nerve impulse in a second cell. If this is an inhibitory synapse, then the postsynaptic cell will become less active. However, each neuron usually synapses with many others, so what happens in the second cell depends on the combined effect of all its synapses.
Subsequently, the neurotransmitters are taken up again by the presynaptic membrane and the whole cycle can be repeated again.

But what exactly do neurons, these basic elements of the brain, do? In the middle of the 19th century, Émile Dubois-Reymond demonstrated the electrical nature of nerve impulses. And by the end of the 19th century, David Ferrier and other researchers showed that electrical stimulation of certain parts of the brain causes specific movements and sensations. Electrical impulses propagating along the fibers of neurons carry signals from one part of the brain to another, activating other neurons there or suppressing their activity. But how can such processes underlie the operation of a device capable of perceiving objects of the surrounding world?

A serious step towards solving this problem was made not even by neurophysiologists, but by design engineers of telephone lines. Telephone lines are like neurons: electrical impulses propagate along both of them. In a telephone line, electrical impulses activate the speaker at the other end of the wire, in the same way that impulses from motor neurons can activate the muscles to which the processes of these neurons lead. But we know that telephone lines are needed not to transmit power, but to transmit messages, whether in the form of speech or in the form of Morse code dots and dashes.

Rice. 5.1. A great tangle that has been untangled. Nerve cells are the basic units that make up the brain. This drawing by Santiago Ramón y Cajal shows nerve cells in the cerebral cortex stained using a technique developed by Camillo Golgi. Numerous neurons of various types and their processes are visible.
Source: Rice. 117, “Coupe tranversal du tubercule quadrijumeau antérieur; lapin âgé de 8 jours, Méthode de Golgi”, from Cajal, S. R. y. (1901). The great unraveled knot. From William Hall, Department of Neuroscience, Duke University Medical Center

Bell Telephone Laboratories engineers were looking for the most efficient way to send telephone messages. In the course of their research, the idea arose that telephone wires actually serve to transmit information. The whole point of transmitting a message is that after receiving it, we know more than before.

Rice. 5.8. Illusion of a convex mask. Photographs of Charlie Chaplin's rotating mask (sequence from right to left and from top to bottom). The face at the bottom right is concave, because we are looking at the mask from the inside, but we involuntarily perceive it as convex, with a protruding nose. In this case, our knowledge that faces are convex takes precedence over what we know about light and shadow.
Source: Professor Richard Gregory, Department of Experimental Psychology, University of Bristol.

How our actions tell us about the world

For the brain, there is a close relationship between perception and action. Our body serves us to learn about the world around us. We interact with the outside world through our body and see what comes of it. This ability was also lacking in early computers. They just looked at the world. They didn't do anything. They didn't have a phone. They didn't make predictions. Perception was given to them with such difficulty, including for this reason.

Even the simplest movements help us separate one perceived object from another. When I look at my garden, I see a fence with a tree behind it. How do I know which brown spots are fence and which are wood? If, according to my model of the world, there is a fence in front of a tree, then I can predict that the sensations associated with the fence and with the tree will change differently when I move my head. Since the fence is closer to me than the tree, the fragments of the fence move before my eyes faster than the fragments of the tree. My brain can bring all these tree fragments together thanks to their coordinated movement. But at the same time I move, the perceiver, and not a tree or a fence.

Rice. 5.9. We can understand where something is through movement When we move past two trees, the closer tree moves faster in our field of vision than the farther deciduous tree. This phenomenon is called motion parallax. It helps us understand that the tree is closer to us than the deciduous tree.

Simple movements help our perception. But movements made for some purpose, which I will call actions, help perception even more. If I have a glass of wine in front of me, I am aware Yu what shape and color it is. But I don't realize that my brain has already calculated what position my hand should take to take this glass by the stem, and anticipates what sensations will arise in my fingers. These preparations and forebodings occur even if I am not going to take this glass in my hand (see Fig. 4.6). Part of the brain maps the world around us in terms of our actions, such as the actions needed to leave a room or take a bottle from a table. Our brain continuously and automatically predicts what movements will be best to carry out this or that action that we may need to perform. Whenever we take an action, these predictions are tested and our model of the world is improved based on the errors in such predictions.

Rice. 4.6. Our brain automatically prepares action programs in accordance with the surrounding objects. Umberto Castiello and his colleagues conducted a series of experiments showing how various objects in the field of view cause the automatic activation of the reactions (programs of actions) required to reach out and take each of these objects into it, even if the person does not have a conscious intention to take them into hands. This was done by very accurately measuring the movements of the hands of the subjects while picking up various objects. When we take something with our hand, the distance between the thumb and the rest of the fingers is adjusted in advance to the size of the object. When I reach for an apple, I open my arm wider than when I reach for a cherry. But if I reach for a cherry while there is an apple on the table besides the cherry, I open my hand wider than I usually do to take the cherry. The action required to take a cherry is affected by the action required to take an apple. Such an influence of a possible action on the performed one shows that the brain simultaneously prepares programs for all these actions in parallel.
Source: Redrawn from: Castiello, U. (2005). The neuroscience of grasping. Nature Reviews Neuroscience, 6 (9), 726–736.

The experience of handling a glass of wine improves my understanding of its shape. In the future, it will be easier for me to understand what form it is through such an imperfect and ambiguous sense as vision.

Our brain learns the world around us by creating models of this world. These are not arbitrary models. They are constantly being improved to give us the best possible predictions of our sensations that arise when interacting with the outside world. But we are not aware of the work of this complex mechanism. So what are we actually aware of?

We perceive not the world, but its model created by the brain

What we perceive is not those raw and ambiguous signals coming from the outside world to our eyes, ears and fingers. Our perception is much richer - it combines all these raw signals with the treasures of our experience. Our perception is a prediction of what should be in the world around us. And this prediction is constantly tested by actions.

But any system, when it fails, makes certain characteristic mistakes. Fortunately, these errors are quite informative. Not only are they important to the system itself in that it learns from them, they are also important to us when we observe the system to understand how it works. They give us an idea of how this system works. What mistakes will a system that works by predictions make? She will have problems in any situation that allows for an ambiguous interpretation, for example, when two different objects of the world around her cause the same sensation. Such problems are usually solved by making one of the possible interpretations much more likely than the other. It is highly unlikely that a rhinoceros is currently in this room. But as a result, the system is deceived when the unlikely interpretation is in fact the correct one. Many of the visual illusions that psychologists love so much work precisely because they trick our brains in this way.

The very strange shape of the Ames room is designed to give us the same visual experience as a regular rectangular room (see Figure 2.8). Both models, the oddly shaped room and the regular rectangular room, are equally good at predicting what our eyes see. But in experience we have dealt with rectangular rooms so much more often that we inevitably see the Ames room as rectangular, and it seems to us that people who move from corner to corner in it increase and decrease in an unthinkable way. The a priori probability (expectation) that we are looking at a room of such a strange shape is so small that our Bayesian brain does not take into account unusual information about the possibility of such a room.

But what happens when we have no a priori reason to prefer one interpretation to another? This happens, for example, with the Necker cube. We might see it as a rather complex flat figure, but in experience we have dealt with cubes much more often. Therefore we see a cube. The problem is that these can be two different cubes. One has the front side at the top right and the other at the bottom left. We have no reason to prefer one interpretation to another, so our perception spontaneously switches from one possible cube to another and back.

Rice. 5.10. Ambiguous images.
Sources: Necker Cube: Necker, L.A. (1832). Observations on some remarkable optical phenomena seen in Switzerland; and on an optical phenomenon which occurs on viewing a figure of a crystal or geometrical solid. The London and Edinburgh Philosophical Magazine and Journal of Science, 1 (5), 329–337. Chalice/faces (Rubin figure): Rubin, E. (1958). figure and ground. In D Beardslee & M. Wertheimer (Ed. and Trans.), Readings in perception(pp. 35–101). Princeton, NJ: Van Nostrand. (Original published 1915.) Wife/mother-in-law: Boring, E.G. (1930). A new ambiguous figure. American Journal of Psychology, 42 (3), 444–445. The original was drawn by renowned cartoonist William Hill and published in the magazine Pack for November 6, 1915.

Even more complex images, such as the figure of Rubin and the portrait of a wife or mother-in-law, demonstrate spontaneous switching from one perceived image to another, also related to the fact that both interpretations are equally plausible. The fact that our brain reacts in this way to ambiguous images is further evidence that our brain is a Bayesian device that learns about the world around us by predicting and searching for the causes of our sensations.

Colors exist only in our minds

You might object that all these ambiguous images are invented by psychologists. We do not encounter such objects in the real world. It's right. But the real world is also ambiguous. Consider the problem of color. We recognize the color of objects solely by the light they reflect.

Color is determined by the wavelength of that light. Long wavelengths are perceived as red, short wavelengths as violet, and intermediate wavelengths as other colors. Our eyes have special receptors that are sensitive to light with different wavelengths. So the signals coming from these receptors tell us what color the tomato is? But here comes the problem. After all, this is not the color of the tomato itself. This is a characteristic of the light reflected by the tomato. If you illuminate a tomato with white light, it reflects red light. That's why it looks red to us. But what if you light the tomato blue? Now it can only reflect blue. Will it now look blue? No. We still perceive it as red. Judging by the colors of all visible objects, our brain decides that they are lit blue and predicts the "true" color that each of these objects should have. Our perception is determined by this predicted color, not by the wavelength of the light entering our eyes. Given that we are seeing this predicted color and not the "true" color, we can create spectacular illusions in which the elements of the picture, from which the color comes from the same wavelength, appear to be colored differently.

Perception is fantasy matching reality

Our brain builds models of the world around us and constantly changes these models based on the signals that reach our senses. Therefore, in fact, we do not perceive the world itself, but its models created by our brain.

These models and the world are not the same, but for us they are essentially the same. We can say that our sensations are fantasies that coincide with reality. Moreover, in the absence of signals from the senses, our brain finds how to fill in the gaps that arise in the incoming information. There is a blind spot in the retina of our eyes where there are no photoreceptors. It is located where all the nerve fibers that carry signals from the retina to the brain come together to form the optic nerve. There is no place for photoreceptors there. We don't realize that we have this blind spot because our brain always finds something to fill this part of the visual field with. Our brain uses signals from the area of the retina immediately surrounding the blind spot to make up for this lack of information.

Place your finger right in front of your eyes and look at it carefully. Then close your left eye and slowly move your finger to the right, but at the same time continue to carefully look straight ahead. At some point, your fingertip will disappear and then reappear after passing through the blind spot. But when there is a blind spot on your fingertip, your brain fills the gap with a pattern on the wallpaper against which the fingertip is visible, and not with the fingertip itself.

But even what we see in the center of our visual field is determined by what our brain expects to see in combination with the actual signals coming from the senses. Sometimes these expectations are so strong that we see what we expect to see, and not what is actually there. This can be confirmed by a spectacular laboratory experiment in which subjects are shown visual stimuli, such as the letters of the alphabet, so quickly that their vision can barely distinguish them. A subject who expects to see the letter A will sometimes remain convinced that he saw it, even though the letter B was actually shown to him.

We are not slaves of our feelings

It may seem that the tendency to hallucinate is too high a price to pay for the ability of our brain to build models of the world around us. Couldn't the system have been set up in such a way that the signals coming from the sense organs always play a major role in our sensations? Then hallucinations would be impossible. But this is actually a bad idea, for a number of reasons. Sensory signals are simply not reliable enough. But more importantly, their dominance would make us slaves to our senses. Our attention, like a butterfly fluttering from flower to flower, would be constantly distracted by something new. Sometimes people become such slaves to their senses due to brain damage. There are people who are involuntarily distracted by everything that their eyes fall on. The man puts on glasses. But then he sees other glasses, and puts them on too. If he sees a glass of wine, he must drink it. If he sees a pencil, he should write something to them. Such people are not able to implement any plan or follow any instructions. It turns out that they usually have severe damage to the frontal lobes of the cortex. Their strange behavior was first described by François Lhermitte.

Patient<...>came to my house.<...>We returned to the bedroom. The bedspread was taken off the bed and the top sheet was folded back as usual. When the patient saw this, he immediately began to undress [including taking off his wig]. He climbed into bed, pulled the sheet up to his chin, and prepared to go to sleep.

Using controlled fantasies, our brain is saved from the tyranny of the environment. In the Babylonian pandemonium of a university party, I can catch the voice of an English professor arguing with me and listen to what she says.

I can find her face among a sea of other faces. Brain imaging studies show that when we decide to pay attention to someone's face, there is an increase in neural activity in the brain in the area associated with the perception of faces, even before the face is in our field of view. The activity of this area increases even when we only imagine someone's face (see Fig. 5.8). That's how powerful our brain's ability to create controlled fantasies is. We can anticipate the appearance of a face in the field of view. We can even imagine a face when in fact there is no face in front of us.

How do we know what is real and what is not?

There are two problems with our fantasies about the world around us. First, how do we know that our brain's model of the world is correct? But this is not the most serious problem. For our interaction with the outside world, it does not matter whether the model built by our brain is correct. The only thing that matters is whether it works. Does it allow you to act adequately and live another day? In general, yes, it does.

As we will see in the next chapter, questions about the “fidelity” of our brain models only arise when it communicates with the brain of another person, and it turns out that his model of the world around us differs from ours.

Another problem was revealed to us in the course of those tomographic studies of face perception. The area of the brain associated with the perception of faces is activated when we see or imagine a face. So how does our brain know when we are actually seeing a face and when we are only imagining it?

In both cases, the brain creates an image of the face. How do we know if there is a real face behind this model? This problem applies not only to faces, but also to anything else.

But this problem is solved very simply. When we only imagine a face, our brain does not receive signals from the senses with which it could compare its predictions. No errors are tracked either. When we see a real face, the model our brain creates is always a bit imperfect. The brain is constantly refining this model to capture all the fleeting changes in that face's expression and all the play of light and shadow. Fortunately, reality is always full of surprises.

Imagination is a very boring thing

We have already seen how visual illusions help us understand how the brain models reality. The aforementioned Necker cube is a well-known visual illusion (see Figure 5.10). We can see in this picture a cube whose front side is directed to the left and down. But then our perception suddenly changes, and we see a cube, the front side of which is directed to the right and up. This is explained very simply. Our brain sees in this picture a cube rather than a flat figure, which is actually there. But as an image of a cube, this drawing is ambiguous. It allows two possible three-dimensional interpretations. Our brains spontaneously switch from one interpretation to another in a relentless attempt to find an option that better matches the signals coming from the senses.

But what happens if I find an inexperienced person who has never seen a Necker Cube before and doesn't know that it seems to point one way or the other? I will show him the drawing briefly so that he can see only one version of the cube. Then I will ask him to imagine this figure. Will there be a switching of images when he looks at this figure in his imagination? It turns out that in the imagination the Necker cube never changes its shape.

Our imagination is completely uncreative. It does not make predictions or correct errors. We don't create anything in our head. We create by putting our thoughts in the form of sketches, strokes and drafts that allow us to benefit from the surprises with which reality is full.

It is thanks to these inexhaustible surprises that interaction with the outside world brings us so much joy.

This chapter shows how our brain learns about the world around us by building models and making predictions. He builds these models by combining information from the senses with our a priori expectations. For this, both sensations and expectations are absolutely necessary. We are not aware of all the work our brain is doing. We are aware only of the models that result from this work. Therefore, it seems to us that we perceive the world around us directly, without making any special efforts.

Chris Frith (Christopher Donald Frith, born in 1942 in England) is an eminent British neurophysiologist, working primarily in the field of neuroimaging.

Since 2007 - Distinguished Professor at the Center for Neurodiagnostics at University College London (Wellcome Trust Center for Neuroimaging at University College London) and Visiting Professor at Aarhus University (University of Aarhus, Denmark). The main scientific interest is the use of functional neuroimaging in the study of higher human cognitive functions.

He studied natural sciences at the University of Cambridge, in 1969 he defended his thesis in experimental psychology.

Author of over 400 publications, including seminal books in neuroscience such as the classic The Cognitive Neuropsychology of Schizophrenia (1992). The popular science book Making Up the Mind (2007) was longlisted for the Royal Society Science Book Award.

Books (2)

Schizophrenia

Schizophrenia - a common mental illness - spoils the life of one in a hundred people, has a devastating effect on those who suffer from it and on their families.

This book tells what the disease really looks like, how it progresses and how it can be treated. The authors of the book summarized the latest research on the biological basis of schizophrenia.

Brain and soul

Brain and soul. How nervous activity shapes our inner world.

It is in this area, along with the study of how we perceive the world around us, act, make choices, remember and feel, that today there is a scientific revolution associated with the introduction of neuroimaging methods. In Brain and Soul, Chris Frith talks about all this in the most accessible and entertaining way.

Reader Comments

Gurka Lamov/ 11/10/2016 No matter how large the number of material (brain) correlates of the functioning of consciousness is, none of them explains the cause of these dependencies. For example, to explain the existence of such dependences by the origin of consciousness from the material activity of the brain is only one of the possible hypotheses. Other reasons can be imagined that are just as legitimate.

Alexei/ 06/30/2010 A good popular science book. How is disease defined? The history of the concept of schizophrenia. Causes of occurrence and scientific search for a solution to this problem. The book is small (200 pages) and will be useful and understandable to an unprepared reader.

Rated the book

A rather simple and unpretentious book "about the brain", quite advanced, but at the same time very lightweight. The author seems to be such a clumsy bum, afraid of his imaginary opponents - the bearer of the humanitarian consciousness of the professor of literature (for sure, that still spectacular little thing) and the aggressive professor of physics, responsible for the attack on the conclusions of all these neuropsychologies from the exact sciences. In principle, this can be understood - this area is really severely interdisciplinary (that is, it is lame on both legs, my inner skeptic tells me), and few people like the results of its activities, since they are very inconvenient. So the author has to literally crawl on the ground on his own, dodging humanitarian howls and caustic attacks (alas, often justified) and trying to lure a not very educated reader into his science. If you have already read something like that about the brain or are generally interested in the current state of affairs in brain science, you will not see interesting new discoveries here. But if you are a beginner and your ideas about how hard the body can deceive itself are limited to simple optical illusions, then you are here. Well, a brief summary: our life is just a dream, but 16 hours a day its content is quite close to objective reality.

Rated the book

I knew! I knew, I knew, I knew! I have always known that my brain and I are completely different personalities and often with opposite desires. If you also thought that you and someone inside your skull were different personalities, don't worry. This is not schizophrenia, but a well-proven scientific fact.

Over the course of three hundred pages, the author explains, with references to scientific research, that every person has a "gray cardinal" in the skull. He paints a picture of the world for us, and with great reluctance admits the mistakes he made in the process, he decides what we will do and convinces us that we did just that, even if this is obviously not the case. The author will give a sufficient number of examples from scientific practice showing that even if we realize the fallacy of the picture of the real world that our “manager” has drawn for us, we will need to spend a lot of time and make certain efforts to prove it to our own brain.

Fritt will quite colorfully prove that everything we know about the reality around us is nothing more than an illusion drawn for us by our brain. And not even always based on signals from the senses. The brain follows the path of the greatest acceleration of the work performed and often finishes the picture simply on the principle of the greatest probability, based on previous experience. So if you suddenly see a flying lilac giraffe outside the window, you will have to argue for a long time with those who are sitting inside the skull and prove that consciousness and vision have not gone crazy. The brain, by the way, will resist and impose its own point of view on these issues. As about the lilac giraffe, and about your own sanity.

Of course, it's not that bad. After all, the brain solves more tasks every second than modern computers could ever dream of. Few people think about the fact that absolutely every movement, even the smallest, up to microscopic changes that allow you not to fall when walking, is sanctioned by the brain. A constant stream of information is processed, analyzed and transformed into signals for the rest of the body. And only a few percent of this our brain considers it necessary to bring to the attention of our consciousness. If we were to receive this data in full, we would go crazy pretty quickly.

This book is not exactly about psychology, as most people understand it, but rather about neuroscience. The author, although he calls himself a psychologist, is much more interested in the physiology of the brain and the processes that occur in it during any activity, both intellectual and physical. That area of science, which most readers call psychology, the author passes over in silence. Although he does not do without some digressions into the history of psychology and psychiatry, and quite regularly goes to Sigmund Freud and his theory. Obviously, Chris Frith dislikes both Freud's theory and Freud himself with all his followers, up to the modern ones. He goes to great lengths to prove that Freudianism is unscientific, erroneous, based solely on assumptions, and generally has nothing to do with psychology in general and Chris Fritt in particular. Well, everyone can have their own opinion on this issue.

The area of scientific interests of Fritt himself lies in the field of higher nervous activity. The book contains many cross-sectional pictures of the brain, in which the reader is shown exactly where the cells will be activated when performing this or that activity, during reflections, fantasies, and the like. In addition, he gives a large number of examples from practice showing the various consequences of impaired brain activity or damage to various areas of the brain.

This book is a good way to understand a little better how the organ of our body works and functions, which, in fact, makes a person a person. Realize how much work he does non-stop throughout his life. But still, if you see a flying lilac giraffe outside the window, do not rush to call an ambulance, even if the brain has already given the hands the command to grab the phone.