[From Rick Marken (980207.1000)]
One thing you do have to say about PCT; it attracts a most
remarkably hostile set of fans;-)
Bruce Abbott asked:
How would the relationship between s and o change if for every
value of i, the PIF returned zero?
If the perceptual function produces no (zero) signal regardless
of the value of i (assuming i = s + o) then there would be no
systematic relationship between s and o.
Now Bruce Abbott (980206.0955 EST) says:
Wrong. During the course of the psychophysical experiment, the
center intensity of the tone was systematically varied across
trials. On some of those trials, the tone was always clearly
perceptible to the participant, and this was evidenced by the
fact that she was able to keep the tone at a constant intensity
despite small disturbances to that intensity.
This shows that the person was able to control tone intensity.
It doesn't seem to have much to do with your question or my
answer to it. You asked a theoretical question about the
behavior of a control system that could not perceive variations
in i. I told you how that system would behave. What does a person's
ability to control auditory intensity have to do with how that
person would behave if they could not perceive that variable? Why
does the person's ability to control intensity make what I said
about the behavior of a "deaf" control system "wrong"?
On other trials, the tone was never perceptible to the participant,
and this was evidenced by the fact that she was unable to keep the
tone's intensity against disturbances.
Which is exactly what I said would happen if the control system
could not perceive variations in i; there is no systematic
relationship between o and s so there is no control of i.
In this case the systematic relationship between s and o was absent.
It would appear that something has changed between these two
conditions. It isn't h() and it isn't g(), and it isn't the ratio
-h()/g(). It isn't a property of the environment that this
experiment reveals. It is a property of the participant's
perceptual input function.
Or of the participant's reference signal. But you are correct; the
results of this experiment do tell you something about the organism.
That's because this study used the method of adjustment, a
psychophysical procedure that is equivalent to The Test. By applying
disturbances to a variable (tone intensity) that the subject could
also influence you can determine that this variable was under
control; you tested for a controlled variable.
If a given participant fails to track a target, is it because the
participant cannot control this particular variable, or just
doesn't care to?
You can't tell. When people are _not_ controlling a variable you
can't learn much about their ability to control that variable.
Now let's return to a traditional psychophysical study of tone
thresholds, one in which the person has control over tone intensity
and is asked to keep the tone crossing just above and below
threshold by pressing or releasing a button.
This may be a "traditional" psychophysical method but it is not
very common. In most psychophysical studies the subject has no
control over the stimulus; so the stimulus in these studies is a
disturbance (by definition because it has sensory effects that
are independent of the subject's output), not a possible controlled
variable (as it is in studies where the subject can influence the
value of the variable. When the stimulus is a disturbance then we
must Test to determine what variable _is_ controlled in these
experiments if we want to learn about the nature of the subject
(and not just about the nature of the subject's connection to the
(unidentified) controlled variable. The results of conventional
psychophysical studies (where the stimulus is a disturbance) may
_suggest_ what variable the subject is controlling but this
suggestion must be Tested (using PCT "aware" methodology). This
is why I say that the results of conventional psychological research
can be a good _strting point_ for doing PCT aware research; but,
as they sit, the results of conventional research tell us little
or nothing about the nature of the organisms under study.
Dan Miller (980206.1130) --
I understand that simulations and models are big with folks who
think they can't study what they really want to study.
Actually, they're also pretty big with folks who think they can
study what they really want to study (like human behavior) and
think that models help them understand what they are studying.
The model is not the thing.
That's correct. It represents the (dynamic) functional relationship
between seen and, most important, unseen variables. The idea is
to see whether the hypothesized relationship between unseen variables
in the model results in behavior (of observable variable) that matches
what we see in the real thing. This is how we do science; it works
like a charm.
I would suggest studying the thing (e.g., lots of different forms
of individual and social behavior) in nature. Make very accurate
descriptions. Don't rely on a metaphor to tell you how the world
works. But these are only suggestions. You can do what you want.
These are the same suggestions that Skinner made; make very accurate
descriptions of behavior and don't rely on "metaphor" (theory). The
fact is that it is very hard to describe without including some
assumptions about _why_ you are seeing what you describe (recall
the discussion of the "theory free" description of the fish returning
to the place where they have found food).
In PCT (and in science in general) we don't _rely_ on what you
call "methaphor" to tell us how the world works; we constantly test
out these metaphors to see if they correcty predict what we see.
A good metaphor (like mass attraction or gravity) is simple but
it explains, with great precision, a great deal of what we can see.
PCT is a good metaphor like gravity; it's simple but explains a
lot of what we see as the behavior of living systems. I agree that
we should be out there studying the real thing -- the behavior of
real living systems -- and some of us are; real people are tested
in most of the experiments at
and you compare the behavior in the baseball demo to the
observed behavior of fielders catching balls to see how well
the model, controlling vertical and lateral velocity, approximates
the behavior of the real thing.
I asked you the questions. You answered in questions.
If I did, it may have been because some of your questions (about
the effects of instructions in our experiments) seemed rhetorical.
As I recall, you asked about how failure to report instructions
might mislead people about our results, how intructions produce
artifactual results and how they make our experiments into S-R
studies. I don't know the answers to these questions; I thought
perhaps you did. They seemed a bit like "when did you stop
beating your wife?" type questions. Like Bill Clinton (who,
thanks to Ken Starr, is quickly becoming my hero) I will just
have to beg off for now. But I would still like to hear why
you think instructions create all these problems for PCT research.
I am disputing your (and others) high correlations. They are
misrepresentations - only possible if you tell and show people
how to do your study.
That's fine. Dispute away. But it would seem much more _tactful_
if you would couch you dispute in terms of actual data. Do
you have data that shows low correlations between, say, output
and net disturbance to a controlled variable that the subject was
not instructed to control? Why do you dispute the results of our
experiments (readily replicated by doing the experiments at:
What evidence do you have to support your dispute? Why are you
so apparently upset about our findings? What are you controlling
I could say that I think that anticipations are absolutely
necessary features of living control systems (not models),
but then I would resort to your ploy - that of the expert.
I don't appeal to my own authority as evidence regarding
anticipation in control. I just haven't seen a demonstration
of controlling that can't be explained in terms of the basic
control of perception model. I don't really care whether or
not anticipation is involved in control; I just haven't seen
any evidence that it is. What's the problem?
I do, however, believe that anticipating is a central property
of control. I've drawn this conclusion from research, reading,
and, of course, my own experience.
Ok. Why not describe the research, reading and experiences that
led you to this conclusion? Maybe it will convince me too.
But the fact that you are convinced doesn't convince me (just
as the fact that I am convinced shouldn't convince you).
This ability to read and comprehend helped me in school, too.
I won't even touch that one;-)
Richard S. Marken Phone or Fax: 310 474-0313
Life Learning Associates e-mail: firstname.lastname@example.org