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AIList Digest Volume 8 Issue 054
AIList Digest Thursday, 18 Aug 1988 Volume 8 : Issue 54
Philosophy:
Human symbol processing
Navigation and symbol manipulation
Can we human being think two different things in parallel?
The Godless assumption
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Date: Sun, 14 Aug 88 13:57:17 -0200
From: Antti Ylikoski <ayl%hutds.hut.fi%FINGATE.BITNET@MITVMA.MIT.EDU>
Subject: human symbol processing
In AIList Digest V8 #47, jbn@glacier.stanford.edu (John B. Nagle)
writes:
>Antti Ylikoski (YLIKOSKI@FINFUN.BITNET) writes:
>>I once heard an (excellent) talk by a person working with Symbolics.
>>(His name is Jim Spoerl.)
>>
>>One line by him especially remained in my mind:
>>
>> ...
>>
>>A very typical example of the human real-time symbol processing is
>>what happens when a person drives a car. Sensory input is analyzed
>>and symbols are formed of it: a traffic sign; a car driving in the
>>same direction and passing; the speed being 50 mph. There is some
>>theory building going on: that black car is in the fast lane and
>>drives, I guess, some 10 mph faster than me, therefore I think it's
>>going to pass me after about half a minute. To a certain extent, the
>>driver's behaviour is rule-based: there is for example a rule saying
>>that whenever you see a red traffic light in front of you you have to
>>stop the car. (I remember someone said in AIList some time ago that
>>rule-based systems are "synthetic", not similar to human information
>>processing. I disagree.)
>
> As someone who works on automatic driving and robot navigation,
>I have to question this. One notable fact is that animals are quite
>good at running around without bumping into things. Horses are capable
>of running with the herd over rough terrain within hours of birth.
>("Horses of the Camargue" has some beautiful pictures of this.) This
>leads one to suspect that the primary mechanisms are not based on
>symbols or rules. Definitely, learning is not required. Horses are
>born with the systems for walking, obstacle avoidance, running, standing up,
>motion vision, foot placement, and small-obstacle jumping fully functional.
>
> ...
>
>In real-world situations, as faced by robots, the processing necessary
>to put the sensory data into a form where rule-based approaches can even
>begin to operate is formidable, and in most non-trivial cases is beyond
>the state of the art.
>
> ...
>
>Personally, I suspect that horse-level performance in navigation and
>squirrel-level performance in manipulation can be achieved without any
>component of the system using mathematical logic.
I won't disagree.
I expressed my thoughts badly; my point was that driving a car is a
different activity from a horse running over uneven terrain, and it
requires symbol processing, even if animals can navigate without logic.
Driving a car could perhaps be described as a combination of already
existing geometric etc. reasoning capabilities and learned symbol
processing skills.
--- Andy Ylikoski
------------------------------
Date: Mon, 15 Aug 88 07:08:54 PDT
From: Stephen Smoliar <smoliar@vaxa.isi.edu>
Subject: navigation and symbol manipulation
John Nagle offered the following observations:
> I would encourage people moving into the AI field to work in the
> vision, spatial, and geometric domains. There are many problems that
> need to be solved, and enough computational power is becoming available
> to address them. Much of the impetus for the past concentration on highly
> abstract domains came from the need to find problems that could be
> addressed with modest computational resources. This is much less of a
> problem today. We are beginning to have adequate tools.
>
> Personally, I suspect that horse-level performance in navigation
> and squirrel-level performance in manipulation can be achieved without
> any component of the system using mathematical logic.
It is also worth noting that Chapter 8 of Gerald Edelman's NEURAL DARWINISM
includes a fascinating discussion of the possible role of interaction between
sensory and motor systems. I think it is fair to say that Edelman shares
Nagle's somewhat jaundiced view of mathematical logic, and his alternative
analysis of the problem makes for very interesting, and probably profitable,
reading.
------------------------------
Date: Mon, 15 Aug 88 09:26:06 PDT
From: norman%ics@ucsd.edu (Donald A Norman-UCSD Cog Sci Dept)
Reply-to: danorman@ucsd.edu
Subject: Can we human being think two different things in parallel?
The question is: Can we human being think two different things in parallel?
the answer is, it all depends you what you mean. This is one of my
research areas, so let me try an answer.
There is a vast literature in psychology on the topic of simultaneous
activity (the area is called the field of "attention.") But the
question is ill-formed, for to answer it requires the definition of
three terms, none of which are well defined:
think
What do you mean by "think"? Any mental activity?
Well, clearly we can normally walk and talk at the same
time, but if I am walking over a slippery, dangerous
mountain peak, I can't: I have to stop talking. And I can
listen to you and watch television. And I can shadow text
coming in one ear (a old, once favorite experimental method)
while doing visual tasks at the same time, but failing to do
verbal tasks.
thing
What constitutes separate things. If the things are on
closely related topics, are they separate? If I do mental
multiplication, is keeping track of the carrys (a working
memory task) a separate thing than doing the table-look up
for the products, or from telling you what I am doing?
Of if I am thinking about tomorrow's dinner, is that
different than navigating my car through heavy traffic
(both require decision making, memory, and planning).
"in parallel."
There are lots of ways of doing things in parallel,
depending upon your deffinition. Rapid time switching
(round-robin time sharing) or independent processing
circuits. Not clear which the human does -- probably both.
But there is probably interaction among the things done in
parallel, so that for many combinations of tasks, although
they are indeed done at the same time, at least one is done
more slowly, less efficiently, or with more errors than were
it being done alone-- so how does this qualify in answer to
the question.
Note that connectionist circuits so far only do one task at
a time, and serially (that is, they can settle into only one
meaningful state at any one time), although they do that
task in a highly parallel fashion. This again, shows the
dificulty of interpreting the question.
So, the question is ill formed and maybe unanswerable. There are,
however, clear and unmistakable limits on how much a person can do
consciously at any one time. But if the skill is highly practiced,
it becomes "automated" and can then evidently be done at the same time
as other things, with either no degradation in either task, or only
small degradation.
If I do 2 things at once, and one is degraded as a result, is this 2
things in parallel?
don norman
(Schedule: I will be away Aug 17 - Sep 2 -- mostly at the
International Congress of Psychology in Sydney, Australia.)
Donald A. Norman
Department of Cognitive Science C-015
University of California, San Diego
La Jolla, California 92093
INTERNET: danorman@ucsd.edu INTERNET: norman@ics.ucsd.edu
BITNET: danorman@ucsd.bitnet UNIX:{decvax,ucbvax,ihnp4}!sdcsvax!ics!norman
(If you reply directly to me, please include your postal
mail address and all possible e-mail addresses. I often
can't answer people because their e-mail paths fail.)
------------------------------
Date: 15 Aug 88 11:53 PDT
From: hayes.pa@Xerox.COM
Subject: Re: think two different things in parallel
YWLee writes
>Can we human being think two different things in parallel?..
>One of my friends said that there should be no problem
> in doing that.
It all depends on what your friend meant by `think'. In one sense, we are
thinking lots of things in parallel all the time. For example, visual
processing is going on ( when your eyes are open ) while you are choosing a form
of words to express what you want to communicate, and something in your head is
listening as well, because if you hear a tiger roar behind you, you will move
really fast. Even quite simple skills seem to require whole lots of parallel
mental activity. You probably didnt mean that, though: you meant something more
like the intuitive sense of think. I dont think we have any clear account of
what that amounts to in terms of cognitive machinery.
But in any case, you wouldnt get the answer to the question by considering the
structure of brains. The brain is clearly a highly parallel machine, but that
doesnt entail anything about the structure of conscious thought.
Pat Hayes
------------------------------
Date: Mon 15 Aug 88 14:20:03-PDT
From: Mike Dante <DANTE@EDWARDS-2060.ARPA>
Subject: Re: The Godless assumption.
I am more than a little surprised by Marvin Minsky's ad hom attack on
Andrew Basden. Would it be equally fair to turn the argument around and
replace "religion" with "science"? For example, would Dr. Minsky feel
that his support for science can be fairly attacked by saying:
>Yes, enough to justify what those who "knew" that they were right did
>to the Kulaks in the name of "Scientific" socialism, or the atrocities
>carried out by Nazi "scientists" on concentration camp victims. There is
>no question that people's beliefs have practical consequences; or did
>you mean to assert that, in your philosophical opinion, they simply
>may have been perfectly correct?
I would hope, that on second thought, Dr. Minsky might agree that Andrew
Basden is no more responsible for burning Bruno than Marvin Minsky is for
experimenting on Jews. And even more, that neither religion nor science has
any justification for being self righteous. Both science and religion have
been used to justify atrocities. I don't see that as any excuse for being a
Luddite in either field.
------------------------------
Date: Wed, 17 Aug 88 09:24 CDT
From: T. Michael O'Leary <HI.OLeary@MCC.COM>
Subject: Assumptions
>Science, though not scientists (unfortunately), rejects the
>validity of religion: it requires that reality is in some sense
>utterly lawful, and that the unlawful, i.e. god, has no place.
To me this requirement is unnecessarily strict. Science does not
require that reality be utterly lawful, but merely that it be possible
for scientists to observe patterns in nature.
When asked (apparently by Napoleon) where God fit into his equations,
Laplace is said to have replied, "I have no need of that hypothesis."
To my way of thinking, if he had been confronted by the assertion of Mr.
Wells shown above, his reply should have been the same.
Michael O'Leary
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End of AIList Digest
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