(Copyright 2008, T. Davidson - All Rights Reserved)
Posted: 11:30 May 26, 2008
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
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