A HISTORY OF THINKING

A HISTORY OF THINKING

PLATO, the Greek philospher who was born in 427BC, was the first to conclude, correctly, that the brain was the ''originating power of the perceptions and hearing and sight and smell''. His student, Aristotle, disagreed, believing the brain had something to do with cooling the blood.

The brain took something of a back seat in philosophical thinking about the body until the birth of moden science. In the early 17th century, Rene Descartes, the French philosopher, chose the pineal gland deep in the brain as the seat of the soul, the point at which the mechnical clockwork mechanism of the body makes connection with the higher spiritual entity of a human being.

Franz Josef Gall (1758-1828), a doctor from Vienna, began to make more serious inroads into the anatomy of the brain, suggesting that different regions could be responsible for controlling different functions. The idea was advanced for its day, but Gall proceeded to elaborate on it, saying that a particularly well-developed characteristic would result in that part of the brain growing in size.

These growths, he postulated, could be felt as bumps on the skull and he claimed to be able to identify 32 possible lumps, for characteristics ranging from philoprogenitiveness (love of children) to hope and wit. Phrenology, as it was called, became extremely popular in the 19th century until it was later shown to be without any foundation.

By the middle of the last century a French doctor and anthropologist, Paul Broca, began the pioneering work on brain surgery that led him to discover areas of the brain responsible for the human skill of putting thoughts into words. Fourteen years later, a German scientist called Carl Wernicke discovered another area of the brain involved in speech. People with damage to this area speak grammatically but the words make little sense. They also have trouble understanding what others are saying.

Even today researchers know these regions of the brain as Broca's area and Wernicke's area. It now seems that Wernicke's area sorts out the meaning of what we want to say and passes this on to Broca's area, which applies the rules of grammar and further triggers another brain region that controls the movements of the facial muscles during speech.

There was something of a hiatus in brain research until the 1930s when Alexander Luria, the Russian neuropsychologist, began to develop the principle of understanding brain function from psychological tests. One of his interests was trying to understand the phenomenal memory of certain people. His ideas spawned a fruitful area of investigation based on batteries of complex tests.

Later, the idea of the ''cognitive approach'' to brain research was born with the work of the British neuropsychologist Elizabeth Warrington. This tried to understand the limitations of brain-damaged people to explain how the healthy brain functions. The cognitive approach focused on issues such as attention, memory or planning and is thought to have helped prepare scientists for the revolution that brain-scanning research created.