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response 3 of 9:
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Aug 14 18:09 UTC 2000 |
We'll get back to the experiment in a moment - first, the book report:
_The User Illusion_, by Tor Norretranders (Viking, 1998), 467pp. (Translated
from Danish)
The author is a Danish "science writer", of the genre that is much more writer
than scientist. He has been called the "Danish James Gleick", after the author
of a popular book on fractals. The author attempts to explain, in lay terms,
what is known about the experience of consciousness that we all share.
Part 1, _Computation_ addresses concepts of information immediately,
starting with the Maxwell Demon conundrum - which apparently is still
not resolved - concerning thermodynamic macroscopic irreversibility.
Now that's a mouthful and involves concepts that are best treated
mathematically, but there is little mathematics in this book, and most
of what there is, is wrong. Nevertheless, I found his account of the
history of attempts to resolve Maxwell's Demon to be interesting.
(What is Maxwell's Demon? It is a hypothetical little person that
controls a door between two chambers and opens the door to let only fast
molecules go from (say) left to right, and only slow molecules from
right to left, thereby causing a temperature difference to develop
between the chambers, violating the 2nd law of thermodynamics *unless*
you can explain that what the Demon does, if done most efficiently,
counterbalances in its actions the decrease in entropy it is causing
to the gas in the system - many eminent physicists have tried and failed.
But the problem involves the thermodynamics of *information*.)
This raises the question of what is information. Shannon defines it as
unpredictability, but this is not very useful in terms of the mind, as the
signal that Shannon would say has the most information is white (random)
noise, since it is unpredictable. But that is not what WE consider
information, which is carved out of noise in order to convey meaning. That
is, to convey meaning, one has to discard information. Tor calls this
discarded information "exformation", and uses Bennett's term "logical
depth" for the meaning kind of information that is left. Since all of
this is posited in non-quantitiative terms, it gets into quite a muddle
about what is what.
(My analogy for this is the block of marble which contains *all* possible
statues that could be carved fromit, and hence contains the maximum
possible information. The sculptor creates exformation during carving by
removing information (possibilities), but increasing the "logical depth".
Just try putting numbers on this and you will realize the problem of
conscousness - the logical depth inherent in all of the sensory input
to the mind. There is, however, a bizarre treatment of random and
nonrandom numbers in this section, which shows that Tor doesn't understand
the concept of probability at all.)
Part 2, _Communication_, applies the prior themes to the mind. The
question addressed, what is the "logical depth" rate, in particular in
bits-per-second, to the mind, into consciousness, and effected by
conscious action. Tor's "bits" are binary choices, but such binary choices
to the mind might be, for example, "up" vs "down", i.e., "chunks". He does
not make this very clear, but others have reported conscious processing
being limited to about "50 bps",whatever they mean by "bits". However
regardless of what is meant by bps in these studies, I think it is obvious
that the input to the mind is in *mega* bps from all the sensory nerves,
but all of this is presented to consciousness at rates of tens of bits per
second. The vast majority - like 99.999% of mental process - is
unconscious and unknown to us.
(How fast can you speak? How many bps would that be in its most compressed
form? How much *processing* was required for that speech prior to your
being conscious of what you are doing? Just consider trying to switch
from English to French, if you have never studied French?)
The title - The User Illusion - comes from this. It is a term for
what a computer user experiences with a GUI (graphic user interface),
as with Macs or Windows, where all of the processing is hidden: we only
experience the result, and already adjusted to the rate at which we
can act upon the result.
Aspects of the User Illusion are such things as subliminal perception
(ideas put into the mind by images shown too quickly to enter
consciousness), the working of memory, intuition and "hunches",
"blindsight", priming, sleepwalking, optical illusions, the invisibility
of the blind-spot of the eye, THINKING.
(From the book): "When did you last have fish for supper?"
"..what did you think about while you were considering when you
last had fish?"
OK, what DID you think about? Can you explain it, so we can do it too?
Tor says, "We are an interpretation."...."What we experience has acquired
meaning before we become conscous of it."
Part 3, _Consciousness_, Electronic measurements of brain function exhibit
what is called a readiness potential. In experiments in which subjects
were asked to make a succession of repetitive actions at intervals they
chose, such as to flex a finger, it was found that the brain started
making the decision before the subject was aware of making a decision and
acting. That is, the subject flexed their finger, but the readiness
potential showed up on an average of 0.8 seconds before.
This has lots of implications. Is some skillful activity, such as ice
skating, a *conscious* act? It can't be, if the brain has to make
preparations for every action some 0.8 seconds before you consciously
execute it, unless the unconscious brain knows what to do in advance. And
how does the unconscious brain know? By training and learning! It doesn't
even have to be something complex like ice skating - *walking* requires
this too, except that the brain is somehow genetically primed to learn
walking (as shown by animals that walk soon after birth).
We now get to the experiments of one Benjamin Libet, a psychologist, who
had the opportunity to conduct them during open brain surgery (with the
consent of the doctors and patient). The brain has no sensory nerves, and
hence feels no pain, so a patient can be conscious during surgery.
Libet found that if an electrical stimulation is applied to the brain
it is felt in an associated part of the body as a tingling. The first
weird result is that the stimulation must be applied for more than about
0.5 second *or it is not felt at all*, or rather, it does not enter
consciousness at all. This is certainly not true of simulations to
the peripheral nervous system.
Libet wanted to explore the timing of sensory perception, so he chose an
areas of the leftscortex that, when stimulated, was felt on the right
hand, and then also stimulated that area of the LEFT hand. The following
results were found: If the stimulation of the left hand and the left
cortex occurred simultaneously, the subject reported that he felt hand
stimulation first. Could the cortex process the information from the hand
faster than when the cortex is directly stimulated? So Libet shifted the
timing of the two stimulations, and found that even if the stimulation of
the hand occurs ca. 0.4 seconds *after* the cortex stimulation, the
subject still felt it first!
After much experimentation, it was concluded that the explanation is as
follows: the cortex received from the hand a very complex sensory input
which was processed and presented to the consciousness 0.5 seconds later,
but with a "wrapper" telling the conscousness it had occurred 0.5 seconds
in the past. How else can this be said. The later hand stimulation was
referred back in how time is perceived in consciousness to be prior to the
direct cortex stimulation.
And thus we come to the experiment in #1. Drew reported that the sound
seemed to be later but the tactile and sight info were (ca.) simultaneous.
But *this is not possible*. The fastest nerve transmission known in the
body is ca. 10 meters per second. So the tactile info had to be delayed by
about 0.1 second to reach the brain, while the sight and hearing info had
to arrive sooner. When I did this experiment, I was convinced that
tactile, sound and sight were simultaneous. But what had happened is that
the later tactile sensation had been "wrapped" in an earlier conscious
time, to appear simultaneously with the others into consciousness,
because that is what is "expected" - the User Illusion.
Part 4, _Composure_. At this point, Tor has run out of material, so the
last part of the book is devoted to many types of wild speculations that
have been generated by other authors, though all in various ways related
to conscousness, or at least our perception of our surroundings: the Gaia
theory, black holes and the BIg Bang, Hamlet (you'll have to read
this....), reductionism and constructionism, chaos, "emergence", phase
transitions, complexity, shape perception, fractals, nuclear weapons, and
much more. One joker has even claimed (and written a book about it), that
human consciousness arose only in the last 3000 years, and its development
is linked to the successive appearance of pantheism, judaism, and
christianity. You can judge for yourself.
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