Re: Analog Processing

From: HARNAD Stevan (
Date: Tue Jun 04 1996 - 22:24:43 BST

> From: "Penny, Rebecca" <>
> Date: Fri, 24 May 1996 16:28:51 GMT
> An analog process is a process that does not use symbolism.

Rather, a symbol system does not use analog (nonarbitrary)

> Symbols are
> arbitary while an analog process is causal, i.e, it is directly linked
> to the original input.

And resembles it.

> Basically, computation manipulates arbitary
> symbols, according to a set of rules, which results in the input, e.g,
> a photograph, being coded and arranged so that it represents the
> original input.

Not clear enough for kid-sib. What does this mean?

> However, analog processes resemble the input by
> creating an analog copy or 'shadow' of the input.
> An example of analog processing is the retinotopic maps observed in the
> brain. These project images from the retina into the visual centre of
> the brain, unchanged.

They are not unchanged, but they preserve local topography.

> This means that the input images become analog
> copies in the brain. The evidence that supports this idea is that
> damage to the visual centre of the brain causes the ability to imagine
> an object or 'image' to be lost.

You mention some of the relevant points, but you must put it together
more coherently, kid-sib-style. You need to discuss images vs. symbols,
pictures vs. words, mental rotation, etc.

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