Yes it all goes against human vanity and we'll all struggle against accepting it but it may well be the way things are going.
On March 15th 2010 scientists announced that they have recreated a 28,000-year-old skull from remains found in France and have found indications that the human brain is shrinking.1 Cro Magnon 1 was discovered among five ancient skeletons in 1868. An initial assessment of the fossil's skull suggested that the brain it encased was up to 20 per cent larger than modern brains, reversing an earlier trend towards bigger brains. This assessment involved the creation of a three dimensional replica of the brain known as an endocast, made by scanning the interior of the skull to obtain a picture of the impression left by the brain on the neurocranium.
Although this new evidence does not suggest that our ancestors were more intelligent as studies have found that the link between brain size and IQ is not well defined, it does raise some very interesting questions.
The researchers have speculated that the shrinkage in brain size might suggest that our brains are becoming more efficient like shrinking computers. But this may also be a sop to our vanity because if this is indeed the case, why did the human brain 'evolve' to be so big in the first place?
Evolutionary theory suggests that advantageous adaptations to the environment are naturally selected through time, in other words those individuals in any particular species who have those advantages will survive longer and produce more offspring. The more the brain grows, the more energy and nutrients it takes away from other vital organs. In fact the brain only takes up 2% of our body weight, but uses 20-25% of our energy intake by far the most of any organ. Thus the natural selection of a larger brain which is to a certain extent redundant and unnecessary is in complete contradiction to the selective mechanism that is presumed to govern human evolution.
Professor John Lorber did a study of individuals who somehow managed to function normally with an IQ over a hundred with only 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 that his 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.
Of approximately sixty cases of hydrocephalus patients who had 95% of the cranial cavity filled with cerebrospinal fluid, half were profoundly retarded. The other half had IQs greater than 100. He admits that CT scans are not easy to read with pinpoint accuracy but also points out: "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."2
So if a smaller brain is all that's necessary how and why did it 'evolve' to be so big, keeping all that wasted capacity for so long and wasting huge amounts of energy to maintain it? What then prompted it to shrink about 28,000 years ago? Could the larger brain could have belonged to a superior species who used it to full capacity? Did we devolve from them?
One of our greatest scientists Dr. Paul Maclean, at the Laboratory of Brain Evolution in Poolesville, Maryland, discovered that the brains of higher living organisms were divided into three distinct schemes of tissue. In other words, we have three distinct brains in our body. Dr.Maclean called it the "triune brain." The three distinct tissue schemes that make up our brain correspond to three distinct behavioural modes. He identified the three tissue schemes respectively as the neocortex, the limbic system, and the cerebellum.3
Interestingly, despite the overall shrinkage in brain size there has been a growth in the size of the cerebellum, seen by Maclean as the most primitive reactive section of the brain. So any ideas that mankind is evolving into a species centred on the higher brained neo-cortex functions (which govern our ability to reason and think holistically) are without foundation. If the more advanced feature, the neo-cortex is more a feature of the past brain than the present brain then what does that say about the evolutionary premise.
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