From: Mary Tobias (mariet@got.net)
Date: Sun Apr 22 2007 - 16:01:45 MDT
Hi Adam,
This isn't a settled conversation by any stretch of the imagination,
though we are speaking strickly about the evolution of the human brain
and it's related intelligence. The greater consensus is that human
evolution around brain size and function is realitvely slow;
University of Chicago geneticist, Chug-I Wu has been comparing the rate
of genetic evolution in the brain among to a wide variety of other
primates (Chimpanzees and Old World Monkees.) When spcifically compared
with Chimapanzees, human evolution among genes related to structure of
the brain are changing at a substantially slower rate for homo sapiens.
When asked "Does this mean that Chimpanzees are catching up with us?" He
answered;
/*"The Human brain's astounding comlexity may be at the root of the
decelerating genetic changes." He adds: "Because genes in the brain code
for proteins that interact with many other molecules, the wiggle room
for evolutionary tinkering is limited. Change a gene to much and it wil
be unable to continue its existing functions. The higher rate of
evolution in chimps, probably just reflects the fact that each gene in
that species has fewer other genes interacting with it than in humans.
Since the complexity of the interactive network of genes likely
determines intelligence, the answer is probably just the opposite."*/
On the flip side, a research in Utah co-authored an article suggesing
that at least the brain-case of human beings is changing at a fairly
radical rate;
Gregory Cochran of the University of Utah in Salt Lake City, Utah, a
coauthor of the study, said the research may force a radical rethinking
of the story of modern human evolution. He is quoted saying “It turns
current thinking upside-down, pretty much,”
/*His oberservation into structural changes in the human cranium suggest
that the rate of human evolution is still quite high. The human brain
case has shrunk significantly over the past 20,000 to 30,000 years. Of
course in that same timframe the human forehead has risen sharpy, and
suggests that the trade-off in certain kinds of brain function in
preference of others (like expanded prfrontal cortex activity) may be an
indication that these changes are part of higher brain functionality of
our species. There is also the likelihood of higher densities in brain
tissue, and structural rearrangement allow for a rather more complex
brain to fit into a smaller braincase.*/
To add a grain of salt to the last reference, the study by Cochran and
his Associate, is generating a bit of controversy, and there seems to be
a significant number of experts in the field who find question with the
conclusions.
The question of making and sustaining a brain of this size is very complex;
* Passing such a big brain through such a small birth canal (~ 10 cm.),
* The dangers of mechanical stress (the larger the brain the larger
the larger the risk for injury due to sudden jerking or rotation
of the skull... you've heard of a "Knock Out" or "Shaken Baby
Syndrome?",
* The growing probability of wiring/neurotransmitter operational
errors, and their related pathologies
A really big brain comes with an extraodinarily high metabolic and
environmental cost. Think about it, if genius had survival value, we'd
be a race of geniuses. The fact that the only people having this
conversation are 2 to 4 sigma out, suggests that the normal daily
process of life does not sellect for brilliance, and that the subsequent
baggage of such "Great Thinking" may be high indeed.
Mary
Adam Safron wrote:
> sl4 discussants,
>
> Thank you for this fascinating conversation. I think our discussions
> could be even better if there were more citing of
> research/background-materials supporting claims. If you have
> particularly informative sources, please share them!
>
> Mary, I would be very interested in reading more about the evidence
> suggesting that human evolution has slowed and potential reasons for this.
>
> A book by Nick Lane, Power, Sex, Suicide: Mitochondria and the Meaning
> of Life, may be relevant to this discussion of evolution. From both a
> design and an empirical/historical perspective, Lane argues that
> though simple cellular life should exist fairly commonly throughout
> the universe, there is a low probability for the evolution of
> eukaryotic cells. And without this symbiotic evolution producing
> mitochondria containing cells, life would not be capable
> (energetically) of supporting the complexity of multicellular
> organisms (thus putting evolved sentience out of the question). This
> hypothesis, combined with our observed timeline of evolution
> (http://en.wikipedia.org/wiki/Timeline_of_evolution) suggests that
> complex-biological-intelligence may not be a major limiting factor
> when compared with other obstacles.
>
> Also, I would appreciate any thoughts on the following idea:
> Is it possible that the astronomical observation of inter-galactic
> voids (http://en.wikipedia.org/wiki/Void_%28astronomy%29) could be
> explained by Dyson Spheres or some similar technology capable of
> absorbing most of the radiation of a star? If an AI were expanding
> outwards from its origins in an exponential fashion, and if complex
> intelligence was such a rare phenomenon that it occurred once every
> several hundred (or thousand) galaxies, perhaps the universe would
> look much like the one observe today: relatively dense filaments of
> galaxies surrounding vast regions of "empty space" Or perhaps the
> universe looks this way for entirely different reasons. And of course,
> as Eliezer pointed out, this would say nothing about whether these AI
> were benevolent to their progenitors.
>
> Best,
> Adam
>
>
> On Apr 19, 2007, at 2:39 AM, Mary Tobias wrote:
>
>
>> In fact recent research suggests that human evolution has come to a
>> near stand-still and is by far the slowest rate of change for all
>> primate. The possible mutations that might improve/expand a brain the
>> size/complexity of ours, without causing serious problems with
>> viability and survivability are approaching zero.
>>
>> The only likely changes in our neural capacity in the near term,
>> won't come until we have a profound understanding of our genome,
>> epigenome, and the machinery of our genetic expression, and the tools
>> withwhich to manipulate them. At that point it's possible that we may
>> be able make tweeks on our own construction, and eek out a few more
>> CCs of prime frontal lobe real estate.
>>
>> Of course by that time, neural implants may make the whole
>> conversation moot.
>>
>> Mary Tobias
>
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