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Posted-Date: Mon, 05 Oct 92 12:37:48 PDT
Newsgroups: bit.listserv.csg-l
Date:         Mon, 5 Oct 1992 12:37:48 PDT
From:         marken@AERO.ORG
Subject:      Why 99%, hierarchical perception

[From Rick Marken (921003.1100)]

Martin Taylor (921003)

>The statistics can give a clue.  If the
>residual variance is proportional to x and to y, logarithms are the likely
>answer.  If it is more or less independent of x+y, then mutiplication is
>probable.  What then?  If a logarithm can be developed in one part of the
>hierarchy, is it not likely that it can be done in another part?  Then perhaps
>we should look for logarithmic relations elsewhere in the hierarchy.  But
>if it looks more as if the answer is multiplication, then a host of different
>relations seem reasonable candidates as the CEVs in other situations.

Martin, trust me (I'm a Dr.). The "Las Vegas" approach to doing research
can now be chucked. No need to analyze residuals, no need to look for
patterns in noise. Just build the models and do what it takes to get them
to behave exactly (to the level you like -- say less than 5% error) like
the real system. Tom Bourbon (921002.1050) -- also a Dr.-- and
Bill Powers (921004.0800) -- not a Dr. but, even better, a genius --
explain the approach extremely well. The method of PCT is modeling.
The method of moribund psychology is statistics.

Bill Powers (921003.0600) --

A wonderful post on the perceptual basis of HPCT. Let me just put in
a quick plug for an approach to exploring perception that I
describe in my soon to be rejected "Hierarchical control of perception"
paper. I have described this on the net (maybe) but I do so again in the
hopes of jogging some of those other minds out there for some suggestions
 -- and maybe develping some new HPCT demos.

The method described in my paper is very simple -- numbers alternate back
and forth on the screen so, with time  going from top to bottom, what is
presented is:

5
     7
8
     2
4
     6
etc...

The rate of alternation can be varied by the observer. When the rate is
very fast (the max possible on the computer -- say about 15/sec -- all
you can see is the numbers -- their configuration. When you slow down the
rate of alteration you get to a point where you see the numbers "move"
back and forth, like the "phi phenomenon". Slow it doen even more and
you can start to see the "sequence" -- you can tell that 5 comes before
7, then comes 8 and then 2, etc. The sequence can by perceived only
when the alternation rate is about 4/sec. If you slow it down even more
you can "see" that there is a rule underlying the sequence -- if number
on left >= 5 then number on right is odd, else number on right is even.
The observer can know this rule in advance but cannot perceive it (at
least, this here observer can't) until the alternation rate is about
.25/sec.

This demo is not supposed to be earth shattering; it is just an attempt
to provide a helpful way for people to examine their own perceptions.
It seems to me that it might help someone understand what it means to perceive
a "configuration", a "transition", a "sequence" and a "program". The
variations in rate help you "isolate" the perceptions and see that it is
possible to have a low level perception (like transition) that
implies the possibility of a higher order perception (a sequence) and still
not be able to perceive the higher level percept (until the rate is slowed).
It is interesting that it seems to take longer to perceive "higher order"
perceptions but this, in itself, does not imply a hierarchical relationship
between the perceptions. Bill's logical test -- that you can't perceive
certain things unless you can perceive their constituents -- seems like a
better basis for claiming hierarchy. Interestingly, the transition perception
goes away when the rate slows too much -- it obviously depends on other
things too -- such as distance between the numbers. But, since we do
see the sequence even though transition is gone, it seems like sequence
perception does not depend on having a perception of transition -- but it
does depend on having a perception of configuration (since it's a sequence
of confugurations).

I think there must be "perceptual demos" of this sort that might help
to demonstrate some ways to look at perception (using our best and
most accessible lab -- our own brain) and see why at least some of us PCTers
think the H in HPCT represents quite a bit more than an opinion.

Best regards

Rick


     **************************************************************

Richard S. Marken                   USMail: 10459 Holman Ave
The Aerospace Corporation                   Los Angeles, CA 90024
E-mail: marken@aero.org
(310) 336-6214 (day)
(310) 474-0313 (evening)
Comments: Gated by NETNEWS@AUVM.AMERICAN.EDU