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Prefrontal Cortex and Evolution

Xuxa Thorson Xoxana at webtv.net
Fri Oct 27 10:19:25 EST 2000

Scientific American: Article: Trends in Neuroscience: 8/97 Address:
http://www.sciam.com/0897issue/0897trends.html Changed:3:02 PM on
Thursday, October 21, 1999
          This article has a wonderful map showing
the different parts of the prefrontal cortex. The main difference
between a human brain and that of other animals is the prefrontal
cortex. Most mammals have little or no prefrontal cortex. However,
monkeys are surprisingly similar to humans, even in the prefrontal
cortex. It has been said that the prefrontal cortex is what makes us
"human". Animal consciousness is very similar to human consciousness.
Psychopaths have little activity in the prefrontal cortex, but still
seem human to the casual observer. The largest difference between
Caucasian and Negroid brains is that Caucasians have a much larger and
better developed prefrontal cortex. This region also plays a major role
in the so-called "culture-fair" intelligence tests, Raven's Matrices.
What these tests measure isn't really intelligence per se, but something
closely correlated with intelligence, at least among members of the same
population. Empathy and concern for the consequences of one's actions
are also in the prefrontal region, at least in humans. "Lower" animals
feel empathy in lower brain regions, apparently. Brain studies of serial
killers show little prefrontal activity. This can be due to either brain
damage or genes.
      Liberals make the false claim that there is no
correlation between intelligence or behavior and the size or condition
of the brain. On the other side, J. Philippe Rushton places too much
emphasis on the overall size of the brain. He is unaware of the fact
that the brain is composed of many parts which play very different
roles. It would be interesting to compare the prefrontal cortices of
Caucasians with those of Mongoloids. Mongoloids are more inhibited in
their behavior, but they also show less empathy. The first would
indicate a large and active prefrontal region. The second would indicate
the opposite. Albert Einstein's brain was very unusual in that it had a
VERY SMALL prefrontal cortex. It is important for people like Rushton to
learn that the brain is very complex, and it cannot be reduced to a
simple formula. http://www.delphi.com/truthseekers8


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