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Saturday, 16 June 2012

The inner workings of the brain and mind


Real time brain scanning technology

The idea of the unconscious, a second level of the mind that is inaccessible to rational thought, but which nevertheless influences people’s behaviour was drawn from Freud's idea of psychoanalysis. During the 20th century, the idea of the unconscious lost its appeal due to the rise of more scientific approaches to psychology. These focused purely on studying behaviour and refrained from theorising about the inner workings of the brain and mind.

A new book on the "unconscious"
 
In a new book entitled “Subliminal”, its author, Leonard Mlodinow shows how the idea of the unconscious has become fashionable again in the 21st century. It has been helped by rigorous experimental evidence of the effects of the subconscious and, especially, by real-time brain-scanning technology that allows researchers to examine what is going on in their subjects’ heads.

This experimental evidence suggests that, as Freud suspected, conscious reasoning makes up a comparatively small part of the activity in the human brains, with most of the work taking place where we are not able to tap into it. However, unlike Freud’s unconscious, the modern unconscious is a place of super-fast data processing, useful survival mechanisms and rules of thumb about the world that have been honed by millions of years of evolution.

It is the unconscious, for instance, that pulls together data on colour, shape, movement and perspective to create the sight enjoyed by the conscious part of the mind. Experiments on people with certain specific forms of brain damage, which remove the ability to perform some of these tasks, can reveal something about what is going on in the unconscious. People with “blindsight” can respond to some visual stimuli even when they are not conscious of being able to see. For example, asked to walk down an obstacle-strewn corridor, they will dodge and weave and arrive at their destination unharmed because some residual data is still making its way into their brains, although at a level that is beneath the notice of their conscious minds.

The modern view of the unconscious mind may be more benign than Freud’s, but it can still generate unwelcome impulses. Psychologists theorise that the well-documented tendency of humans to categorise almost every piece of information they come across is a survival mechanism that evolved to aid quick decision making. Yet it may also lie behind the tendency for human beings to group people into races, genders, creeds and the like, and then to apply certain characteristics, often unjustifiably, to every member of that group.

The insights offered by modern science into the workings of the human mind are fascinating in their own right. But they also suggest that plenty of conventional wisdom about how humans behave may need rethinking. In his new book, Mlodinow notes that economic models, for instance, are built on the assumption that people make decisions by consciously weighing the relevant factors, whereas the psychological research suggests that, most of the time, they do no such thing. Instead, they act on the basis of simple, unconscious rules that can sometimes produce completely irrational results. 

Consciousness and Self

Consciousness is the core of an individual's sense of self, yet, paradoxically, it is the most elusive concept in biology. One feature of human consciousness that students of the field suggest might be unique is an awareness of self. The idea that self-awareness might be specific to humans and a few close relatives resulted from an experiment done three decades ago by Gordon Gallup, who now works at the University of Albany in New York state. This showed that chimpanzees (and, as subsequently emerged, other great apes) share with humans the ability to recognise themselves in a mirror, whereas monkeys and various other reasonably intelligent species, such as dogs, do not. A few species that are not apes have also passed the mirror test, including elephants and dolphins. But most animals fail it. All the species that have passed have something in common: abnormally large cerebral cortices relative to the rest of their brains. Whether selfawareness simply emerges from a large cortex or whether selection for it necessarily results in one is unclear. 

What is consciously perceived is not a simple mapping of the images that fall on the retina. Instead, the signals from the optic nerves are deconstructed and re-formed in a process so demanding that it involves about a third of the cerebral cortex. An even more obvious discord between reality and perception is colour. The world is not really coloured, it just looks that way because it is tremendously useful that it should, so the retina has cells that are particularly sensitive to three different wavelengths of light, and the brain weaves the signals from them together to create the phenomenon called colour.

For some time we have believed that conscious free-willed thought could override unconscious desires. But one way of interpreting the inner workings of the brain and mind is that it is possible, that such free will is, like colour vision, simply a powerful illusion. But the truth, unsatisfactory though it is, is that no one really knows. But one thing we can be sure of is that neuroscience is one area where big concepts almost certainly remain to be discovered. And when they are, they are likely to upend humanity's understanding of itself.
 
 




 

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