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From: wcalvin@milton.u.washington.edu (William Calvin)
Newsgroups: comp.ai.philosophy
Subject: Re: "Emotion" vs. "Understanding" (was: Re: emergent properties)
Message-ID: <9099@milton.u.washington.edu>
Date: 12 Oct 90 16:38:28 GMT
References: <15268@venera.isi.edu> <3679@media-lab.MEDIA.MIT.EDU> <15276@venera.isi.edu>
Organization: University of Washington, Seattle
Lines: 30

One of the problems is dealing with the time dimension in brain
function is that there is no master clock, no lock-step to processing
that insures catch-up by slower processes (as in microprocessors). 
	To use an example that I put somewhere in THE CEREBRAL
SYMPHONY as "The Postal Principle," the difference between conduction
velocities in various branches of motor cortex neurons are
order-of-magnitude.  In particular, branches crossing from one
cerebral hemisphere to the other tend to be rather slow, in
comparison to the cortex-to-spinal cord branches.  And so it takes
about as long for the muscles to be made aware of the message as it
does the other side of the brain.  It's like the familiar finding
that it takes about as long for a letter to cross town as it does to
cross the country.
	I think that the interesting ways of how the brain handles
time are to be found in the sequencing specializations of (in
particular) left brain.  This permits episodic memories (where
everything stays strung together, as in a film clip or sound bite),
and it permits scenarios to be constructed, to be judged against the
imperfect episodic memories for reasonableness.  Quite a little
darwinian shaping-up can be done that way, allowing an initially
awkward plan of movement to be shaped up into one that has a much
better chance of success, even though totally novel (with no perfect
matches from memories).  The connected-time specializations, rather
than time in the usual sense of a microprocessor actions, are thus
not only interesting in themselves but also because of their
relevance to creating such novelities of hominid evolution as grammatical
language, music, and dance. 


                  William H. Calvin             wcalvin@u.washington.edu