left and right brain – the evidence

Here is some of the research that adds weight to the propositions outlined in ‘Left in the Dark’, i.e. that the left brain is a less functional version of the right and that there is extraordinary latent potential in the right hemisphere waiting to be liberated from cerebral dominance by the left hemisphere.

Current views about the specialisations of the left and right hemispheres of the the brain have been largely formed by the research of Roger Sperry in the 1960′s. He found that the left side of th
e brain currently controls analytical and verbal tasks while the right half takes care of the space perception tasks and music, for example. The right hemisphere is involved when you are making a map or giving directions on how to get to your home from the bus station. The right hemisphere can only produce rudimentary words and phrases, but contributes emotional context to language. Without the help from the right hemisphere, you would be able to read a word but you would not be able to imagine what it is. The right half deals with feeling matters hence the famous Roger Sperry quote: “The great pleasure and feeling in my right brain is more than my left brain can find the words to tell you.”

In the last three decades remarkable characteristics have been discovered about the right hemisphere of the brain.

In the 1980′s Canadian professor Michael Persinger discovered that euphoric or mystical experiences can be accessed when weak but complex magnetic fields are applied to the right hemisphere of the brain. The same effect can not be produced with the left hemisphere. An interesting correlation is that certain psychedelic substances do not produce altered states of consciousness in people who have lost the use of the right hemisphere.

In the 1990′s Professor Allan Snyder at the Centre of the Mind in Australia began conducting research involving temporarily shutting down the left temporal lobe of the brain using transcranial magnetic stimulation. During the experiments enhanced artistic and mathematical ability and improved memory emerge. In Snyder’s words: ”You could call this a creativity-amplifying machine. It’s a way of altering our states of mind without taking drugs like mescaline. You can make people see the raw data of the world as it is. As it is actually represented in the unconscious mind of all of us.” A number of Allan Snyder’s subjects have reported perceptual changes too – feelings of euphoria and bliss more normally associated with ‘peak experiences’ and meditation.

The skills that emerged in Allan Snyder’s experiments mirror those of autistic savants and also occur in some people whose left hemisphere has been damaged. Darold Treffert, Clinical Professor at University of Wisconsin Medical School, has studied savant syndrome for over forty years. His book ‘Extraordinary People’ was the first comprehensive summary of autistic savant syndrome and is probably the world authority on autistic savants. In a recent statement he has said: ‘I’ve come more and more to the conclusion that rather than there being right hemisphere compensation, there is rather release from the ‘tyranny’ of the left hemisphere’

Yet more evidence of the remarkable capacities of the right hemisphere has been revealed by the experiences of neuroanatomist Jill Bolte Taylor. In 1996 she had a severe haemorrhage in the left hemisphere of her brain. Her account tells like a mystical experience. Because mental and physical function is habitually dominated by the left hemisphere, much was initially lost as a result of the trauma of the stroke. However as a result the functions of Jill Bolte Taylor’s right hemisphere blossomed.

It seems that when left hemisphere influence is removed mystical sensations and advanced function emerge. So what happens when right hemisphere function is lost?

A fascinating sense of how the left hemisphere of the brain operates when it is deprived of the influence of the right hemisphere is given by the condition of anosognosia. Anosognosia is the name for a condition where a person has a disability and does not know that they have that disability. It occurs as a result of neurological damage and is usually seen in patients who have had a right hemisphere stroke, resulting in a paralysis of the left side of the body. In fact anosognosia occurs in over half of right hemisphere stroke patients (J. Cutting put the figure at 58% in a study described in 1978), while it hardly ever occurs in left hemisphere stroke victims. Some of these patients vehemently deny the paralysis and, in extreme cases may ascribe the arm to another person such as a spouse or even the examining physician. They often employ defence mechanisms to account for their failure e.g. ‘I don’t feel like moving my arm right now’. This apparent lying where the person actually believes what they are saying is true is called confabulation. Confabulation can be defined as the formation of false memories, perceptions, or beliefs.

Clues as to how this situation with the left hemisphere of the brain may have arisen are currently coming out of Cambridge University where Professor Simon Baron-Cohen has researching the effects of hormones on brain growth and behaviour. He is best known for his work on autism, including his theory that autism is an extreme form of the “male brain”. He has added to the growing body of evidence that testosterone retards the neural development of the left side of the brain and this detrimentally alters behaviour.

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