What the Neocortex Does

Sergio Navega snavega at attglobal.net
Thu Aug 3 06:26:09 EST 2000

Harry Erwin wrote in message <1eeqgyr.190b4m51bhoz2qN%herwin at gmu.edu>...
>Sergio Navega <snavega at attglobal.net> wrote:
>> Harry Erwin wrote in message <1eeoeeq.1l5du7o1hdv8vwN%herwin at gmu.edu>...
>> >I'm beginning to suspect a primary function of the neocortex is the
>> >maintenance of a non-symbolic, dynamic model of the environment. The
>> >evidence seems fairly strong that bats live mostly in such a model
>> >(Griffin, 1958), and the difficulty we have training bats to use
>> >symbolic representations (yes/no tokens) in communicating with us,
>> >suggests that their internal model is non-symbolic, possibly like the
>> >analog models used in some contexts like wind tunnels and floatation
>> >tanks.
>> >
>> >--
>> >Harry Erwin, PhD, <mailto:herwin at gmu.edu>,Computational Neuroscientist
>> >(modeling bat behavior), Senior SW Analyst and Security Engineer, and
>> >Adjunct Professor of Computer Science, GMU. Looking--CV available at:
>> ><http://mason.gmu.edu/~herwin/CV.htm>
>> If you're modeling bat behavior, I think you should also consider
>> symbolic alternatives.
>> What? Are you saying that bats may have symbols in their brains?
>> Yes, I am. Symbols, in a broader definition, are not necessarily
>> discrete and precise elements. This arrow -> is a symbol for a
>> concept of flow or direction. But that very same symbol could
>> be written as ==>> or any other representation. What a bat may
>> have in its "mind" could be thought as a vague representation of
>> its world, but that is certainly symbolic: it is a neural pattern
>> of activations that *represent* an object or event in its world.
>> A symbol is an object that stands for another object.
>> Regards,
>> Sergio Navega.
>Consider a wind-tunnel model.  Where are the symbols?

A wind-tunnel doesn't interact with outside world. It is a
self-contained system that doesn't alter its simulation in
tandem with what happens outside. It doesn't have any sensory
system. Any system that is symbolic (in the way I used the
word) must accept information from sensory entrances and
from that information derive models which are able to predict
near term future. A bat that is in pursuit of a prey does
exactly that and although some processes in its brain may
be seen as analogical and dynamic, they can also be seen as
a collection of symbol-like entities interacting with each
other according to some "rules" or "grammar". It is up to
us to discover what these "rules" are.

Sergio Navega.

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