From: rickert@mp.cs.niu.edu (Neil Rickert)
Subject: Re: Memory and store/retrieve.
Organization: Northern Illinois University
Date: Wed, 29 Jul 1992 16:56:48 GMT

In article <1992Jul28.194953.7337@puma.ATL.GE.COM> ljones@andrew.ATL.GE.COM (LeRoy E Jones) writes:
>Neil writes:
>[...]
>> With human memory there is much to suggest that there is a steady
>>accretion of information, rather than atomic storage events.

>Even if we use the word accretion, there still is a store operation to hold
>the new information.

  Except that (a) there is no control over the accretion, so it is hardly
		  an operation,
	      (b) the actual information that is recorded might be very
		  different from what you think is recorded.

>                                              I think the word "encode"
>is better than store, but the net effect is a store because I can say a
>number to you, and if I ask you that number soon afterwards, you can probably
                                             ^^^^^^^^^^^^^^^          ^^^^^^^^
>tell me.

  Notice your equivocation.  These restrictions should not apply if
there were a genuine and retrieve.

  With your use of "soon afterwards", you are evidently referring to
short term memory, whereas I was mostly referring to long term memory.
Short term memory presumably has something to do with temporary
preservation of the current state of the mind, or of some components of
that state.

  You do remind me of a major point which I carelessly omitted from my
previous posting.  Your example refers to remembering a number.  A
number, or a word, is encoded in language.  Language is particularly
significant here.  For the nature of language is such as to greatly
enhance the ways memory is used.  It is with linguistically encoded
information that we come closest to having a store/retrieve memory.

>         Memory deteriorates (even in a computer which uses store/retieve),
>so you may not be able to tell me if I wait too long, but for a while, you
>store that number.

  If you leave a magnetic tape for many years, it may eventually suffer
catastrophic failure on some sections of the tape, so the information
can not be recovered.  But as we usually think of computer memory, it
does not deteriorate except when there is a catastrophic failure.  The
resistance to deterioration is perhaps the fundamentally most important
property of digital information.

>> Likewise, with retrieval, there is much about the way we remember to
>>suggest that we are really inferring the information rather than using
>>an atomic retrieval event.  We talk about searching our memory, but the
>>search time is really the time we use to make the inference.

>These examples simply suggest that people build individual semantic networks
>to encode information.

  Certainly the representation of information is likely to be very
individual.  But I think it a serious mistake to assume there is something
like a semantic network.  A semantic network is an organized way of
representing information.  If you were designing an information system,
you would certainly try to organize the information.  But evolution does
not work that way.  You can hardly imagine the idea of evolution thinking
to itself "well, one day this fish will evolve to a human, so lets come
up with an information storage plan that can be suitably extended."  It
is just not going to work that way.

  It seems much more likely that the information that is in memory
consists of a somewhat random collection of small fragments of information.
The information you think is there may not actually be there, but related
information might be present.  This is why I want to describe what seems
to us to be a memory retrieval as actually an inference of the desired
information from the fragments of related information that happen to be
present in memory.

>                                        It is largely accepted that meaning
>is what is encoded by the mind,

  With the one problem that "meaning" is not well defined.

>                                and in that sense I agree that the retrieval
>of a particular fact is often an inference based on the meaning assigned to
>it since the time of initial encoding. This brings up an issue of granularity.
>I assert that human memory stores information which it operates on, although
>the representation of that info in the mind is not predictable, and that it
>is capable to retrieve information, although the retrieval process varies in
>complexity based on the representation of the information.

  My only disagreement here is with the use of the words "store" and
"retrieve".  It does make a difference.  Suppose two people see the same
events, and then come up with very different and conflicting descriptions.
If storage and retrieval is involved, then you can assert that one of
them is lying.  However if memory actually consists of the accretion of
fragments of information, and if retrieval is really an inference, then
all you can say is that the two people made different inferences.  The
situation often does arise where two people tell quite contradictory
stories, yet both appear to be telling the truth.  Such a situation is
not easily reconciled with store/retrieve, but is not surprising at all
with accretion/inference.

>>But the human memory is
>>a marvel when it comes to recognition.  You can pick out one face in a
>>crowd.  You can learn all kinds of new patterns, and learn to recognize
>>them.  This is a remarkable and important ability, and may be one of
>>the most important aspects of our intelligence.
>
>Yeah, but recognition requires storing of information and patterns somehow.
>You can't derive, infer, recognize from no information.

  I fully concur that recognition requires information, and consequently
needs some type of memory.  I only question whether it is legitimate to
say that a store operation is involved.

  Let me make an analogy.  From time to time you take your automobile
in for a tune up.  The mechanic adjusts the spark gaps in your spark
plugs, adjusts the idle screw on your carburettor, adjusts the points
in the distributer, and perhaps slightly rotates the distributer so that
it fires at exactly the right time.  Is it correct to say that what the
mechanic is doing is storing information in your automobile?  Personally
I would find that a strange use of the word "store".  Yet learning may
quite possibly consist of making many small adjustments, and so be
somewhat comparable to the tuneup.

>In summary, I think this all started with trying to define intelligence, and
>the only practical intelligence is an evident intelligence. Intelligence
>that exists but has no impact on the world, is useless.

  I certainly agree with this.

  Thank you for some thoughtful comments and responses to my ideas.