norman%ics@SDCSVAX.UCSD.EDU (Donald A. Norman) (06/30/87)
A comment on sin in AI, or "Why did the $6M man run so slowly
AI researchers seem to like the sin of armchair reasoning. It's a
pleasant sin: comfortable, fun, stimulating. And nobody can ever be
proven right or wrong. Most scientists, on the other hand, believe
that real answers are generated through the collection of data,
interpreted by validated theories.
The question "why did the $6M man run so slowly" is a case in point,
but my answer is also stimulated by the conference on "Foundation of
AI" that I just attended (held at MIT, arguing about the several
theoretical approaches to the representationa and simulation of
intelligence). In AIlist, many folks have let forth their theories.
Some are clever, some are interesting. Some are probably right, some
are probably wrong. How would one ever know which? Letting forth
with opinions is no way to answer a scientific question.
At the conference, many of AI's most famed luminaries let forth with
their opinions. Psychological phenomena made up and explained faster
than the speed of thought. Same observation applies. The only thing
worse is when a researcher (in any discipline) becomes a parent. then
the theories spin wildly and take the form: my child did the following
thing; therefore, all children do it; and therefore here is how the
mind works.
Same for why the $6M man ran so slowly. If you really want to know
why slow motion was used, ASK THE FILM MAKER ! (producer, camerman,
editor, director). The film maker selected this method for one of
several possible reasons, and armchair reasoning about it will get you
nowhere. It might have been to stretch out the film, for budgetary
reasons, because they didn't know anything else to do, because they
accidentally hit the slow-motion switch once and, once they got
started on this direction, all future films had to be consistent, etc.
One suspects that filmmakers did not go through the long elaborated
reasoning that some of the respondents assumed. Whatever the reason,
the best (and perhaps only) way to find out is to ask the people who
made the decision. Of course, they themselves may not know, given
that much of our actions are not consciously known to us and do not
necessarly follow from neat declarative rurles stored in some nice
simple memory format (which is why expert systems methodology is
fundamentally flawed, but that is another story), but at least the
verbally described reasons can give you a starting point.
Note that the discussion has confounded several different questions.
One question is "why did the film makers chose to use slow motion?" A
second question is, given that they made that choice, "Why does the
slow motion presentation of speeded motion produce a reasonable
efffect on the viewer?" Here the answer can only come about through
experimentation. However, for this question, the armchair
explanations make more sense and can start out as a plausible set of
hypotheses to be examined.
A third question has gotten raised in the discusion, which is "during
times of stress, or incipient danger, or doing a rapid task when very
well skilled, does subjective time pass more slowly?" This is an
oft-reported finding. Damn-near impossible to test. (Possible,
though: subjective time, for example, changes with body temperature,
going faster when body temperature is raised, slower when lowered, and
since it is possible to determine that fact experimentally, you should
be able to determine the other). The nature of subjective time is
most complex, but evidence would have it that filled time passes quite
differently than unfilled time, and the expert or person intensly
focusssed upon events is apt to attend to details not normally
visible, hence filling the time interval with numerous more activity
and events, hence changing th perception of time.
But before you all bombard the net with lots of anectodes about what
it felt like when in you auto accient, or skiing incident or ..., let
me remind you that the experience you have DURING the event itself, is
quite different from your memory of that experience. The
esdperimental research on time perception shows that subjective
durations can reverse. ( Events that may be boring to experence --
time passes every so slowly -- may be judged to have taken almost no
time at all in future retrospections -- no remembered events. Events
with numerous things happening -- so quickly that you didn't have time
to respond to most of them -- in retropsect may seem to have taken
forever.)
The moral is that understanding the human (or animal) mind is most
difficult, it is apt to come about only through a combination of
experimental study, theoretical modeling, and simulation, and armchair
thinking, while fun, is pretty irrelevant to the endeavor.
Psychology, the field, can be frustrating to the non-participant.
Many tedious experiments. Dumb experiments. An insistence on
methodology that borders on the insane. And an apparent inability to
answer even the simplest questions. Guilty. But for reason. Thinking
about "how the mind works" is fun, but not science, not the way to get
to the correct answer.
don norman
Donald A. Norman
Institute for Cognitive Science C-015
University of California, San Diego
La Jolla, California 92093
norman@nprdc.arpa {decvax,ucbvax,ihnp4}!sdcsvax!ics!norman
norman@sdics.ucsd.edu norman%sdics.ucsd.edu@RELAY.CS.NET