My brain releases me from dull, repetitive task of recognising the things in the world around me, and even saves me from needing to think about how to control my movements. I can concentrate on the important things of life: making friends and sharing ideas. But, of course, my brain doesn't just save me from tedious chores. My brain creates the „me“ that is released into the social world. Moreover, it is my brain that enables me to share my mental life with my friends and thereby allows us to create something bigger than any of us are capable of on our own.
For a while psychologists pretended to be real scientists by studying only behaviour: making objective measurements of things like movements and button presses and reaction times. But studying behaviour is never enough. It misses out on everything that is interesting about human experience. We all know that our mental life is just as real as our lives in the physical world. Now we psychologists are back studying subjective experience: perception, recollections, intentions. But the problem remains: the mental things that we study have a completely different status from the material things that other scientists study. The only way I can know about the things in your mind is because you tell me about them.
A science that explains how the brain creates the mind.
In this book I shall show that this distinction between the mental and physical is false. It is an illusion created by the brain. Everything we know, whether it is about the physical or mental world, comes to us through our brain. But our brains connection with the physical world of objects is no more direct than our brains connection with the mental world of ideas. By hiding from us all the unconscious inferences that it makes, our brain creates the illusion that we have direct contact with objects in the physical world. And at the same time our brain creates the illusion that our own mental world is isolated in private.
Through these two illusions we experience ourselves as agents, acting independently upon the world. Over the millennia this ability to share experience has created human culture, that has, in its turn, modified the functioning of the human brain. By seeing through these illusions created by our brain, we can begin to develop a science that explains how the brain creates the mind.
I have shown that even an ordinary, healthy brain does not always give us a true picture of the world. Because we have no direct connection to the physical world around us, our brains have to make inferences about that world on the basis of the crude sensations they receive from our eyes, ears, and all the other sense organs. These inferences can be wrong. Furthermore there are all sorts of things our brains know that never reach our conscious minds.
The brains map of the world
Through associative learning the brain constructs a map of the world. This is essentially a map of value. The map locates the objects of high-value where I am likely to be rewarded and the objects of low value where I am not likely to be rewarded.
The invisible actor at the centre of the world.
Through its ability to learn and predict, my brain ties me to the world with many strong threads. Because of these threads, the world is not the buzzing, confusing mass of sensations; instead, everything around me excerpts of push or pull because my brain has learnt to attach values to them. And my brain creates more than mere pushes and pulls. It even specifies all the actions I might need to perform to reach some things and avoid others. But I am not aware of these strong connections - my brain creates the illusion that I am an independent being quite separate from this physical world.
Our perception of the world is a fantasy that coincides with reality.
The remarkable thing about our perception of the physical world in all its beauty and detail is that it seems so easy. In our experience, our perception is not a problem. But this very experience that our perception of the physical world is easy and immediate is an illusion created by our brains.
We didn't know about this illusion until we tried to make machines that could do perception. The only way to find out whether perception is easier difficult is to try to make an artificial brain that will perceive things. In order to make such a brain, we need to identify the components from which it is built and we need to know what these components do.
The information revolution: 19th century: the neuron doctrine – neurons – synapses.
What do the neurons, these building blocks of the brain, actually do? By the middle of the 19th century, Emil du Bois-Reymond had demonstrated the electrical basis of nerve impulses. The electrical impulses in the nerves carry energy from one brain area to another where activity in other nerve cells can be enhanced or inhibited. But how can such activity be the basis of a machine that can perceive objects?
The major advances did not come from students of brains physiology, but from telephone engineers. Telephone lines are like neurons: electrical impulses travel along both. The electrical impulses in a telephone line activate the loudspeaker at the other end, just as the electrical impulses in motor neurons can activate the muscles they are attached to. But we know that what telephone lines transmit is not energy, but messages, whether in the form of speech or as the dots and dashes that compose Morse code.
The development of information theory and the digital computer revealed that perception is a hard problem to solve. But our brains have solved this problem. Does this mean that the digital computer is not a good metaphor for the brain? Or do we need to find new kinds of computations for the computers to carry out?
The problem with the scheme provided by information theory is that it takes no account of the viewer. In this scheme all viewers are the same and then experience of the stimulus will be the same. But we know that all viewers are different. They have different past experiences and different expectations. And these differences affect how we perceive things, our prior knowledge influences our perception.
The Rev Thomas Bayes: How can we modifiy information theory so that it can take account of the different experiences and expectations of viewers? We need to retain the insight that the message is informative if it is unexpected unsurprising. But we must now add our new insight that the message may be more surprising to one person and to another. An objectively surprising and unexpected message may be defined as one that changes our view of the world and hence our behaviour.
We can also say that the message is informative to the extent that it changes the receiver's beliefs about the world. In order to know how much information is the message conveyed to the receiver, we need to know about the belief of the receiver before the message arrived. We can then see how much this belief changed once the message was received. But is it possible to measure prior beliefs and changes in beliefs? Probability provides a measure of how much I believe in something.
In my brain, perception depends upon prior belief. It is not a linear process like that which produces an image on a photograph or on a TV screen. For my brain, perception is a loop.
In a linear version of perception, energy in the form of light or sound waves would strike the senses and these clues about the outside world would somehow be transmitted and classified by the brain into objects in certain positions in space. It was this approach that made perception so difficult for the first generation of computers.
A brain that uses prediction works in almost the opposite way. When we perceive something, we actually start on the inside: a prior belief, which is a model of a world in which there are objects in certain positions in space. Using this model, my brain can't predict what signals my eyes and ears should be receiving. These predictions are compared with the actual signals, and, of course, there will be errors. My brain welcomes these errors. These errors teach my brain to perceive.
How action tells us about the world: For the brain, perception and action are intimately linked the use our bodies to learn about the world. We do things to the world with our bodies and see what happens. This is another feature that early computers lacked. They just looked at the world. They did not do things. They had no bodies. They did not make predictions. This is another reason why perception and was so difficult for them.
My brain discovers what is out there in the world by constructing models of that world. These models are not arbitrary. They are adjusted to give the best possible predictions of my sensations as I act upon the world. But I'm not aware of this complex mechanism. So what is it that I'm aware of?
Chapter 6: How brains model other minds: It is our brain that enables us to enter the world of other minds. How can our brain do this?
...our knowledge of the physical world is essentially subjective. What I know about the physical world is captured in a model of that world created by my brain. This model is created from my prior knowledge and the cues provided by my senses.My knowledge of the mental world, a world of other minds, can be created in exactly the same way. From the cues provided by my senses my brain creates a model of a mental world of beliefs, desires, and intentions. Mirror neurons: Our brains have an automatic tendency to imitate any movement that we see...To imitate someone, we watch their movements closely, but we don't copy these movements. We use the movements to discover something in the mind of the person you're watching: the goal of their movement. Then we imitate them by making the movements that achieves the same goal.
As soon as we perceive movements in terms of goals, they become special. Anything can simply “move”: rocks can roll in the stream, branches can thrash in the wind. But only certain creatures move of their own accord in order to attain their goals. I will call the these goal-directed movements actions. And it is only the actions of creatures with goals (which I will call agents) that I brain will automatically imitate. Imitation gives us access to the private mental worlds of others.
The experience of agency:The experience of being in control, of deciding to do something and then doing it, of being an agent in control of our destiny. We are all agents. But there is more to our sense of agency than performing actions to achieve goals. We make choices. We are not just agents. We are free agents. At least for small things in life, we all believe that we are in control than can cause things to happen. This is the mystery of mind over matter: the way thought can make things happen in the physical world.
Agents make things happen. Being an agent is all about cause and effect. Our brains are very good at linking cause and effect. It is all a matter of prediction and timing. The effect follows the cause. Having a observed the cause, we can predict what the effect will be and when it will occur. This is what the brain does. It makes predictions about the world and then checks how well these predictions work. Through this process of prediction the brain discovers which causes go with which effects. These causes and effects are then bound together to form units which are actions performed by agents.
I think that I have direct contact with the physical world, but this is an illusion created by my brain. My brain creates models of the physical world by combining signals from my senses and prior expectations, and it is these models that I'm aware of. I acquire my knowledge of the mental world - the minds of others - in the same way. However it may seem to me, my contact with the mental world is neither more or less direct than my contact with the physical world. Using cues acquired from my senses and prior knowledge acquired from my experience, my brain creates models of the minds of others.
Culture and the brain: Sharing Minds – How the Brain creates Culture
The problem with translation: We spend most of our time living in a mental world created by our brains - even when we are assaulted by the real world around us. For most of the time I'm oblivious to the physical world around me. (But) I am not daydreaming in a private world of my own. I am reading books and newspapers. I have entered someone else's mental world.
Without doubt our brains most remarkable achievement is to permit communication between minds. The purpose of writing this book is to transfer ideas from my mind into yours. Sending ideas from one mind to another seems vital, almost a compulsion, for us. But if each mind is a private place, then this process of communication is impossible - isn't it?
...our brain solves this problem by using guesses about the world to predict what will happen next as react upon the world. The errors in our prediction enable us to refine our guesses until we have a good model of what is out there in the world. In the same way we (or rather our brains) guess what someone's goal may be and then predict what they will do next. We guess what someone is trying to communicate to us and then predict what she will say next.
...So how do we start with our guessing? Making guesses about what people are like before we have any information about them is pre-judging them. It is prejudice. Prejudice is in fact crucial for our brains to function. (Long before numerous scientists became Bayesians, prejudice had already been rehabilitated by Hans Georg Gadamer in this development of hermeneutics (the theory of understanding). Rather than closing us off, he suggests, our prejudices (prior knowledge) open us up to what is to be understood.)
Prejudice enables us to start our guessing - and it doesn't matter how accurate the guesses, as long as we adjust our next guess in response to the error. Prejudice has been built in by evolution....there's nothing special about the problem of minds. When I look at a tree in the garden, I don't have the tree in my mind. What I have in my mind is a model (or representation) of that reconstructed by my brain. This model is built up through a series of guesses and predictions. In the same way, when I'm trying to tell you something, I can't have your idea in my mind, but my brain, again through guesses and predictions, can construct a model (a representation) of your idea in my mind. Now I have two things in my mind: my idea and my model of your idea. I can compare them directly.
Communication, when we confront each other face-to-face, is not a one-way process from me to you. The way you respond to me alters the way I respond to you. This is a communication loop. In addition it is not just me who is trying to predict what you will say next on the basis of my model of your idea. You will also have a model of my idea in your mind. You are also trying to predict what I will say next. You also will alter what you say to indicate that your model of my meaning is not quite working to predict what I'm going to say.
This is the big difference from my interactions with the physical world. The physical world is utterly indifferent to my attempts to interpret it.
When two people interact face-to-face, their exchange of meaning is a cooperative venture. The flow is never just one way. Even when my aim is to communicate an idea to you, inevitably the idea that it's finally communicated will have been coloured by you.
By building models of the mental world, our brains have solved the problem of how to get inside the minds of others. And it is this ability to make models of the mental world that has created the great gap between humans and all other species. Without the ability to build and share mental models of the world, there would be no such things as language and culture.
Our ability to make models of the mental world opens up an entirely new way of changing the behaviour of others. In the physical world, behaviour is changed by rewards and punishments. We stop doing things that cause pain. We repeat actions that lead to pleasure. We can alter the behaviour of others using pain and pleasure - this is how we train animals.
But in the mental world behaviour is changed by knowledge. I will take an umbrella with me, not because it is raining now, but because I believe it is going to rain later this afternoon. And we can use knowledge to change the behaviour of others. The sharing of experiences is not just words. When I tell you of my experience, your brain will change as if you had the same experience.
Our brains ability to communicate ideas from one mind to another can bring horror as well as benefit. We all know how easy it is to be deceived by false beliefs. Our mental currency consists of beliefs created by our brains.
By making models of the minds of others (in the same way that it makes models of the physical world), my brain enables me to enter a shared mental world. By sharing my mental world with others, I can also learn from their experiences and adopt the models of others that are better than my own. From this process, truth and progress can emerge, but so can deception and mass delusions.
Me and my brain: We are embedded in the mental world of others just as we are in bedded in the physical world. What we are currently doing and thinking is moulded by whomever we are interacting with.
But this is not how we experience ourselves. We experience ourselves as agents with minds of our own. This is the final illusion created by our brains.
If we look at the person and the brain in isolation, then the frontal cortex is the ultimate source of control. But people and their brains are rarely found in isolation. Isolation is bad for them. The human brain is essentially tuned for interactions with other people. Concepts like will, responsibility, and even meaning arise from these interactions.
Conveying meaning from one mind to another depends upon interaction. We each predict what the other will say and adjust our predictions until we reach mutual agreement. As a result the final meaning agreed-upon depends on both people and therefore will be slightly different depending on whom we are talking to. Meaning arises from the interactions between brains.
If we want to understand the neural basis of these interactions, it is no good looking at just one brain. We need to study to brains as they interact this programme of research is only just beginning.
...There is an intimate relationship between our experience that we are free agents and our willingness to be altruistic, feeling pleased when we are behaving fairly ourselves and feeling upset by the unfairness of others. For these feelings to arise it is crucial that we experience ourselves and others as free agents. We believe that all of us make deliberate choices. Otherwise I willingness to cooperate would fall apart. This final illusion created by our brain - that we are detached from the social world and free agents - enables us to create together a society and culture that is so much more than any individual.
Chris Frith: Making up the Mind - Summary