Most people don't know this but the human brain has shrunk dramatically through the millennia of the history of mankind. Scientists are in some disagreement as to whether this shrinkage started thirty thousand years ago, or ten thousand years ago, but they agree that the brain has shrunk by 8-10%. The brain has in fact been shrinking for the past 100,000 years albeit at a slower rate.

Another conundrum for evolutionary biologists is why the human brain 'evolved' to be so big in the first place! It gobbles up an extraordinary amount of energy. It only takes up 2% of our body weight, but uses 20-25% of our energy intake - far more than any other organ. The more the brain grows, the more energy and nutrients it takes away from other vital organs.

The necessity for such a large brain in evolutionary terms was thrown in doubt by Professor John Lorber's study, detailing individuals who somehow managed to function normally with an IQ over a hundred, with nothing more than a sliver of brain tissue. One boy had an IQ of 126 and a first class honours degree in mathematics despite the fact he had "virtually no brain". A CAT scan showed the boy's skull was lined with a thin layer of brain cells to a millimeter in thickness. The rest of his skull was filled with cerebrospinal fluid. The young man continued a normal life with virtually no brain.

From over 600 scans of people with hydrocephalus Lorber documented just under 10% with 95% of the cranial cavity filled with cerebrospinal fluid. Half of this group were profoundly retarded. The remaining half had IQs greater than 100. Sceptics have claimed that it was an error of interpretation of the scans themselves. Lorber himself admits that reading a CAT scan can be tricky. He also has said that he would not make such a claim without evidence. In answer to attacks that he has not precisely measured the amount of brain tissue missing, he added, "I can't say whether the mathematics student has a brain weighing 50 grams or 150 grams, but it is clear that it is nowhere near the normal 1.5 kilograms."

All this throws up startling questions:

WHY DID THE HUMAN BRAIN GROW TO BE SO UNNECESSARILY LARGE IN TERMS OF OUR EVOLUTIONARY SURVIVAL AND PROGRESS?

WHY DID THE BRAIN MAINTAIN THIS SIZE FOR SO LONG DESPITE THE FACT THAT IT USED UP SO MUCH ENERGY?

WHY DID IT SUDDENLY START TO SHRINK 30,000 YEARS AGO? IF THE SIZE OF THE BRAIN IS A SIGN OF THE EVOLUTIONARY PROGRESS OF AN ORGANISM DOES THAT MEAN THAT WE ARE WE NOW DEVOLVING? IF A SMALLER BRAIN IS ALL THAT'S NECESSARY IN EVOLUTIONARY TERMS HOW DID THE BRAIN GET TO BE SO BIG IN THE FIRST PLACE?

I am reminded of a book called 'The Song Of The Greys' by Nigel Kerner. In 1998 when the book was published, long before this affirmation about the shrinking brain size, he made a stunning case for the suggestion that we did not evolve from a sea-worm. We 'devolved' from something much much better than we are now. The large brain is just a remnant of what we once were, that's why it's shrinking. Kerner also suggests that the 95% of the human genome that does not seem to code for proteins was also at one time in the ancient past used in full, we have, in other words, lost 95% of our potential through devolution.

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