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From: prune@athena.mit.edu (Paul Berland)
Newsgroups: comp.ai.philosophy
Subject: Re: Dreams(Garbage collection)
Message-ID: <1991Mar30.023454.12481@athena.mit.edu>
Date: 30 Mar 91 02:34:54 GMT
References: <1991Mar25.114410.45892@vaxb.acs.unt.edu> <schraudo.670039946@beowulf> <1991Mar27.162850.4397@mercury.cair.du.edu>
Sender: prune@athena.mit.edu (Paul)
Organization: Massachusetts Institute of Technology
Lines: 46

In article <1991Mar27.162850.4397@mercury.cair.du.edu>, ttoupin@diana.cair.du.edu (Tory Toupin) writes:
|> In article <schraudo.670039946@beowulf> schraudo@beowulf.ucsd.edu (Nici Schraudolph) writes:
|> >munawar@vaxb.acs.unt.edu writes:
|> >
|> >>I was wondering whether dreams are our brain's method of
|> >>garbage collection(like done with computer memory)
|> >>Has anybody done any research in to it?

There have been many theories about the role of dreaming but none have been
scientifically verified yet.  Your analogy might be useful at some stage of
the investigation, but it can only hope to describe part of what dreaming
does.  There is much of dreaming which is a creative process just as in the
awake state.  In this creative process, new patterns and structures are
formed and stored; something which falls outside of garbage-collection.
Think of all the inspirations people have when dreaming.

|> >Crick & Mitchison have speculated that the function of dream sleep might be
|> >to remove parasitic modes -- "false memories" that occur in some neural net
|> >architectures under heavy storage loads.  The idea is that in REM sleep the
|> >brain "runs" in reverse, _unlearning_ from experience.  Since there's no
|> >sensory input, experiences in REM sleep (ie. dreams) are dominated by the
|> >parasitic modes.

There is some evidence that would make us think that things resembling brains
use processes resembling dreaming for garbage-collection, but still we are
dealing with analogies.  Useful?  Maybe.

|> How about this: the brain is attempting to piece together memories to form
|> temporary concepts -- a form of forethought?  That is to say, memories are
|> symbols of the state of the body when the memory was formed, and the brain
|> tends to superimpose(?) these symbols...and see if they are physically
|> possible situations based on the knowledge of situations which can/have
|> occurred by trying these memories out on the "virtual body" (i.e.: the
|> so-called mind's eye, but the entire body as well) and if it is not
|> physically possible, it mutates the symbols slightly so that
|> they are not associated as well with one another.

This idea I find less plausible than the garbage-collection one, even as a
sub-process.  Dreams work with symbols not physical objects and situations.
Dreams progress using logic much different than the rules of our world so
that the "physically possible situations" cannot be determined in the dream
state.  Many physically impossible situations occur routinely without
benefit of critical analysis, which is performed by a part of the mind
which is usually asleep.  This idea would be more plausible to me if it
described not the test of physical processes but the test of symbolic
forms.  That is a much more common theory in dream psychology.