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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.
For our brains it is not a buzzing blooming confusion we see around us, but the map of signs about future possibilities. And through this map of future possibilities our bodies are intimately tied to the world immediately around us. I just have to look at that mug over there and my brain starts tensing my muscles and curling my fingers in case I should want to reach for it.
This is how our minds becoming embedded in the physical world, how our brains learn about the world without needing a teacher. This map has no memory. As long as our predictions are correct, the pattern remains stable. The failure of prediction shakes up the pattern so that a new one can emerge to replace the old one. In this way we can adapt our behaviour to an ever-changing world.
Page 100
The dramatic discrepancy between what our brains know about the world and our conscious experience of the world.
Associative learning can explain how our brains acquire knowledge about the world, but we are hardly aware of this knowledge all its acquisition. What, then, is the experience of the world that our brains create?
Whatever my brain may be doing, I do not experience myself embedded in the physical world. I experience myself in the physical world, but detached from it. My brain may have cleverly embedded me in the physical world, but I am not aware of this embedding.
Associative learning is vital for our survival. It allows us to respond quickly and efficiently to the world. Through associative learning we acquire important knowledge about the physical world. But we are hardly aware of this knowledge, our minds are on higher things. And usually these higher things are our own private wishes and desires.
Page 105
The feeling of being in control
There are many reasons why prediction is a good thing. If we know what is going to happen, then we can relax. We don't have to keep making our plans about what to do. We need to change our plans only when something unexpected happens. Also if we know what is going to happen, then we feel that we are in control. We all like the feeling of being in control. And the thing we control best is our own body. Yet, paradoxically, because our brain suppresses the bodily sensations it can predict, we feel most in control when we don't feel anything. I reach for my glass and all I experience is the look and taste of the wine as I drink it. I don't experience the various corrections made to the movements as my brain navigates my arm through the various obstacles on the table to reach the wine glass. I don't experience the changes of the angles of my elbow or feel of the glass on my fingertips as they adjust perfectly to the size of the stem. I feel in control of myself because I know what I want to do (have a drink) I can achieve this aim without any parent effort. As long as I stay in control, I don't have to bother whith the physical world of actions and sensations. I can stay in the subjective world of desires and pleasures.
The world of the imagination.
The Professor of English thinks I am talking nonsense. "You may move through the world like a zombie, she says, but I am certainly aware of what I'm doing."
"No, I reply. Most of the time you're not aware of what you're doing what you are aware of is what you intend to do. As long as your intentions are fulfilled, you're not aware of what movements you're actually making.
We can live in this world of intentions, this imaginary world, because our brain can predict the consequences of our movements. Our brain knows in advance how long the movement will take, what I hand it will look like at the end, and what the movement should feel like. And even if we do not move at all, we can imagine making movements.
Page 106
We learn by prediction. My brain predicts what is going to happen when I move and uses the error in its prediction to do better next time. But if we don't move, there is no final outcome to compare with a prediction. There is no error. So how can I learn by simply imagining making a movement? Learning in the imagination is possible because my brain makes two different predictions about my movements. First it can predict which particular sequence of commands sent to my muscles will generate a movement I want to make. This prediction is called the inverse model because my brain has to reason backward from the output of my motor system to its input.
Second, my brain can predict which exact movements will occur in every sense a certain sequence of commands to my muscles. This prediction is called the forward model since my brain has to reason forward from input to output. My brain cannot test how good either of these predictions of about making movements.
But we don't need to make movements to test whether or not the two predictions are consistent with one another. The prediction from the forward model, which finger movements will occur, should match the starting point of the inverse model, which finger movements I want to make. My brain can make these two predictions and adjust them until they match without my making any actual finger movements. As a result of such purely mental practice my ability to make the real movements will improve.
Page 107
Moving through the world and reaching for the things we want seems easy. We take it for granted. In the normal state of feeling of being in control of our actions is marked by a lack of awareness of the details of the actions we are performing. We have little awareness of our sensation when we move and we are rarely aware of having to make corrections to our movements even though we are making them all the time. But, in the background, our brain is work in a hard to achieve this sense of ease.
Page 109
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.
Whenever I act in the world, moving my limbs and removing myself from one place to another, I cause massive changes in the signals striking my senses. The pattern of sensations on the retina at the back of my eye changes completely every few seconds. But the world outside has not really changed. And my brain manages to create the experience of a constant, unchanging world through which I move. I can choose to attend to the various parts of my body, and then they do become part of this external world.
Through associative learning our brains discover the valuable things in the world and what actions we need to take to get them.
Chris Frith
Neuroscience
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