Technology has been revolutionising the field of psychology. Whereas in the past, the only evidence available to the psychologist was the first-person reports from patients telling how they felt, it is now possible to explore the brain itself.
First came the MRI, magnetic resonance imaging, which allowed researchers to examine the structure of the brain and to detect those areas which were damaged. For the first time, it became possible to correlate the changes in the responses of patients, to the damage identified in the brain.
It had already been possible to make observations from brain-damaged patients and to correlate specific areas of the brain with particular functionality. So for example, we know where the primary visual cortex is located, and the consequences of damaging it. We know where the area of the brain is that controls our motion of grasping objects. Mapping the brain into regions of particular functionality gave psychologists a crucial step forward in understanding mental function.
The next really big step though was fMRI, functional MRI, which by measuring the blood flow into particular regions of the brain, showed the increase of brain activity in real time. A patient performing a particular mental task could be monitored and changes in their brain activity could be recorded. For the first time, it was possible to see what happened in the brain when patients were thinking and feeling.
Chris Frith, a Professor of Neuropsychology, was fortunate in being in at the start of this technological advance, and in Making Up the Mind: How the Brain Creates Our Mental World he presents us with a description of the tools used by modern brain scientists. He gives us a startling insight into what our brains do for us, how they construct our model of the physical world, and our minds.
We all naturally think that our perception of the external world is accurate and correct: why else would it work so consistently for us? By and large, that view is quite correct. The model we have of the world works because our brains constantly make predictions about how the world behaves and when we test it by our actions, the errors are detected and the model is improved. This correction means that we are always improving our model of the physical world, making it more useful.
Frith explains how our brain filters out a vast amount of what we perceive. Our vision is constantly corrected by the brain to allow for everything from indistinct features on the edge of our field of view, through to filling in the blind spot on our retinas so we see complete scenes. Our brain routinely compensates for inadequate perception by filling in the details by prediction. Frith provides a wonderfully entertaining account of the experiments and cases that illustrate this predictive activity of our brains in the field of perception, and also what happens when it goes wrong.
But perhaps the most important part of Making Up the Mind is where he shows that our brains construct not just a model of the physical world, but also a model of our own mental world. Since we are part of the physical world, we might also perceive ourselves that way. In fact though, our brains hide many of the details of our physical selves, reducing the physical sensations when we interact with the outside world, so that we can concentrate on the important things.
For example, when we go to pick something up, we do not become conscious of the position of every part of our body, but only those parts of us that are directed to the act of picking up. This filter gives us the illusion of being separate from the world.
This is a crucial point in understanding how we perceive our self. That self-consciousness, argues Frith, is a reflection of the hiding mechanism in the brain, which gives us the sense of being in control, being able to act.
He presents a well-known but interesting set of experiments conducted by Libet in which he showed that the brain reacts to an intention even before the subject is aware of having the intention. Philosophers have long puzzled over the implications for this for free will – if the brain has already committed to an action, then in what sense is there free will?
Frith shows how this doesn't remove free will but simply casts it in a different light. Our perception of the physical world is really our perception of the brain's model of the physical world.
This being the case, the mind of an individual is in fact, a property of the brain itself. It is that perception of the mental model produced by the brain. So the mind is not separate from the brain. In fact, it goes further than that. Just as the brain adjusts its model of the physical world by predicting and checking how accurate the predictions were, it does just the same for the mental model as well.
We constantly predict through our mental model what other people are thinking, we assess their reactions, make judgements about how they feel, and we detect subtle inaccuracies and make corrections. That's how we interact with other people. That's how culture comes about.
But there is also a very neat tie-up with brain activity and chemistry. When we empathise with someone, we actually make small, almost imperceptible changes in our own expressions, moving the facial muscles. The consequent changes in brain activity mirror closely those changes in the other person's brain. We empathise by recreating a similar state in our own mind, and hence we can experience similar feelings.
Making Up the Mind is a truly fascinating book which cuts through a great deal of the mystification of how brains and minds work. Anyone who still thinks the mind is something separate from the brain will find many many challenging arguments in this book.
It is written in an engaging and entertaining style and Frith manages to combine hard science (even if psychology is often considered a soft science) with a simple explanation of complex topics. It's a short book but packed with information and ideas and it's entertaining. What more could you want?