Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!ucbvax!pasteur!sim!brp
From: brp@sim.uucp (bruce raoul parnas)
Newsgroups: comp.ai.neural-nets
Subject: Re: NN Question
Message-ID: <10624@pasteur.Berkeley.EDU>
Date: 3 Mar 89 02:02:08 GMT
References: <32125@gt-cmmsr.GATECH.EDU>
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Reply-To: brp@sim.UUCP (bruce raoul parnas)
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Organization: University of California, Berkeley
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In article <32125@gt-cmmsr.GATECH.EDU> kirlik@hms3.gatech.edu (Alex Kirlik) writes:
>Why should a net with only a few dozen neural units be
>successful at mimicking human behavior that is presumably
>the result of the activation of a tremendous number of
>neurons?  That is, why should a small number of units

I beg to differ substantially on this claim.  No man made neural networks have
yet come close to modelling/mimicking human behavior, no matter what the level
of abstraction we assume.  They do not reflect the temporal properties, and are
totally incapable of *MANY* of the things humans can do.  Neural nets take 
inputs and associate them with outputs, nothing more.  They do not reflect even
the simplest levels of cognition!

>
>I know that the validity of this question depends upon the
>"level" at which we interpret our models, but, after all,

At no level is this valid, i believe.
>
>One answer would seem to be that there is a tremendous amount
>of additional processing in the brain that is extraneous to
>the processing critical to the task being modeled, yet we are
>only modeling this "critical" segment. For many reasons (that

Natural selection would eliminate a great deal of "extraneous" processing

I think that a great many people view neural networks as good models for what
goes on inside our heads.  Since these models are, mainly, discrete time
automata they do not reflect the fact that real neural systems are, essentially,nonlinear continuous-time multi-dimensional vector spaces in which the neurons
evolve in time.  So while they are real neat computational tools, they are far
from representing real neural processes.

bruce (brp@sim)