# Skepticism, S-R and Control, PCT Research

**URL:** <http://discourse.iapct.org/t/skepticism-s-r-and-control-pct-research/10527>\
**Category:** CSG1995\
**Created:** [May 24, 1995, 5:03pm UTC](http://discourse.iapct.org/t/skepticism-s-r-and-control-pct-research/10527 "1995-05-24T17:03:06Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![Richard\_Marken](http://discourse.iapct.org/letter_avatar_proxy/v4/letter/r/9fc348/32.png) [@Richard\_Marken](http://discourse.iapct.org/u/Richard_Marken)\
**Post date:** [May 24, 1995, 5:03pm UTC](http://discourse.iapct.org/t/skepticism-s-r-and-control-pct-research/10527/1 "1995-05-24T17:03:06Z")

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[From Rick Marken (950524.1000)]

My experiments with Hans' model-based control program have shown me once  
again the importance of being skeptical; it is especially important to be  
able to doubt what you \_want\_ to believe most. It is important, that is, if  
you want to avoid wasting time trying to explain things that don't exist.

I proposed one such explanation myself (950523.1130) when I said:

> The control that appears to exist when ft = .1 and pff = .01 is, apparently,  
> an artifact; it probably results from the oscillation in u is that is set up  
> by the the Kalman filter based control of x; with ft = .1 and pff = .01, the  
> oscillations may just happen to be the opposite of the disturbance that  
> "comes with the program".

It turns out that the "control that appears to exist" doesn't; it's not an  
artifact because it's not anything; Hans' program exhibits no "model- based"  
control at all. So my explanation of this "phenomenon" in terms of  
coincidental oscillations that "just happen to be the opposite of the  
disturbance" is completely irrelevant. It's rather like an explanation of  
the phenomenon of "reinforcement" -- a make-believe explanation of a make-  
believe phenomenon.

Failure to be skeptical about "model-based control" led others besides myself  
to some claims and explanations that can now be seen to be irrelevant because  
they are based on the presumed existance of a phenomenon (model-based  
control) that does not exist. For example, here is part of Hans Blom's  
(950522) explanation of model- based control:

> Because gamma and delta are set to values greater than zero, forgetting  
> forces continuous relearning. And the relearning attempts to subsume the  
> sine wave into the model. Therefore the parameter estimates become rather  
> meaningless. But control is fine! ... By the way, "forgetting" in my demo,  
> including the new one, may be far too drastic and/or done in an  
> inappropriate way.

This is an explanation of how a model does something that it doesn't actually  
do -- control.

Martin Taylor (950523 16:40) falls victim to the same temptation (to explain  
something before we know it exists):

> if you model the world as introducing the kind of noise effect that the hot  
> air from the fire would introduce, then your perception can be stabilized in  
> part by ignoring the noise effects... The practiced hunter is controlling  
> for the perception that the cursor (foresight) is aligned with where the  
> target (animal) is.

Martin uses a model that doesn't work (model-based control) to explain a  
phenomenon that doesn't exist (controlling for alighnment of the  
foresight with "where the animal is" -- the equivalent of controlling xt --  
when the perception of that reality is corrupted by noise).

Even Bill Leach (950523.22:22) gets caught up in the excitement:

> It seems to me that this thing could control depending upon what the  
> output of the Kalman filter is capable of doing to the model.

> Such a "control loop" seems appropriate to me for systems with poor  
> quality "perception" but very constrained "xt".

In fact, this thing (Hans' model) cannot control at all so it's makes no  
sense to apply it to any task where control is involved.

Seeing these speculations (including my own) about a non-existant phenomenon  
helped me understand more deeply what has been going on in the behavioral  
sciences for the last hundred years or so. What we have is a lot of  
authoritative and important sounding explanations of phenomena that don't  
actually exist; they are just misinterpretations of the phenomenon of  
control. Attempts to explain, for example, reinforcement (the apparent  
selective effects of stimuli on behavior) are equivalent to my attempts to  
explain the apprent "control" found in model-based control demo.

Bruce Abbott (950524.1000 EST) --

Bruce:

> The signal to stop flying comes from sensors on the foot pads.

Me:

> Signalus-response?

Bruce:

> Not necessarily, but I don't seem to have a fly/bee wiring diagram here in  
> front of me at the moment, so it's a little hard to tell.

You won't find evidence against the stimulus-response view in the fly/bee  
wiring diagram. You have to look at the whole loop. It may be true that what  
is felt at the foot pad affects flying; but then it is also true (from  
observation) that flying affects what is felt at the foot pads. So the S-R  
relationship between foot pad sensor and flying is part of a closed loop; if  
this is a stable, negative feedback (ie. a control) loop, then the perceptual  
variable in this loop is under control; what is felt at the foot pads (the  
perception) is not a "signal": it is a controlled variable.

> By the way, I'm finding a treasure-trove of control system research in this  
> area. Did you know about it?

Only a bit. We heard about some studies of beavers (reported by G. Cziko)  
that showed that the beaver apparently builds dams to control an auditory  
perception of "rushing water", keeping that perception at zero.

> Next time you're in an academic library, take a look at \_The Journal of  
> Experimental Biology\_. It would appear that biologists, at least, are  
> having little trouble getting control system studies published

There are control system studies and then there are PERCEPTUAL control  
system studies. It's the latter that have been tough to publish. There are a  
bazillion published studies of manual control in psychology, for example.  
Many of these are fine but they don't get at the basic PCT question -- what  
perception(s) is the organism controlling. I suspect that many of the  
control system studies in biology are equivalent to the "manual control" type  
studies in psychology. I would bet that studies done to determine the  
perceptual variables that organisms control are as rare in the biological  
as they are in psychological literature. My experience is that studies like  
the bee study described by Avery and the "baseball catching" study in Science  
are the rare exception rather than the rule-- in biology and in psychology.  
It may be that there are, in fact, more PCT-like studies in the biological  
literature. That would be a pleasant surprise, especially of there were a  
fair number of them.

Best

Rick

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**Author:** ![\_Martin\_Taylor](http://discourse.iapct.org/letter_avatar_proxy/v4/letter/_/a9adbd/32.png) [@\_Martin\_Taylor](http://discourse.iapct.org/u/_Martin_Taylor)\
**Post date:** [May 24, 1995, 6:03pm UTC](http://discourse.iapct.org/t/skepticism-s-r-and-control-pct-research/10527/2 "1995-05-24T18:03:11Z")

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[Martin Taylor 950524 14:00]

> Rick Marken (950524.1000)

> > if you model the world as introducing the kind of noise effect that the hot  
> > air from the fire would introduce, then your perception can be stabilized in  
> > part by ignoring the noise effects... The practiced hunter is controlling  
> > for the perception that the cursor (foresight) is aligned with where the  
> > target (animal) is.
> 
> Martin uses a model that doesn't work (model-based control) to explain a  
> phenomenon that doesn't exist (controlling for alighnment of the  
> foresight with "where the animal is" -- the equivalent of controlling xt --  
> when the perception of that reality is corrupted by noise).

Rick might note that I did not use ANY model in my discussion. I merely  
suggested to him that even if Hans' model worked, it would in no way  
detract from the notion that what is controlled is perception. Hans  
did not provide a counter-example to PCT, which is what Rick assumed  
he had done.

I don't hunt, but I have grave doubts as to whether a real hunter  
would try to change the aim as the apparent position of the target moves  
with the heat shimmy. I still claim that the hunter is controlling his  
own perception.

If you want to take the "out" that the heat waver is faster the hunter can  
move the gun, think of another scenario, a spear-fisherman fishing from the  
bank of a stream. If he throws the spear at the position where the fish  
seems to be, he will die of hunger before catching a fish. The refraction  
at the water surface changes the apparent depth of the fish, and any slow  
waves on the surface may make it seem to move back and forth.

The skilled hunter catches fish. I claim that in doing so he is controlling  
his perceptions. If I understood Rick's earlier comment on Hans' posting,  
Rick would say that if the hunter hits the fish with the spear, he is  
demonstrably NOT controlling his perceptions, but is instead controlling  
an outer-world variable. Success in controlling one's perceptions by means  
of actions in the outer world is not incompatible with PCT.

Martin

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**Author:** ![Bill\_Leach1](http://discourse.iapct.org/letter_avatar_proxy/v4/letter/b/848f3c/32.png) [@Bill\_Leach1](http://discourse.iapct.org/u/Bill_Leach1)\
**Post date:** [May 26, 1995, 2:25am UTC](http://discourse.iapct.org/t/skepticism-s-r-and-control-pct-research/10527/3 "1995-05-26T02:25:27Z")

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\<[Bill Leach 950525.21:37 U.S. Eastern Time Zone]

> [From Rick Marken (950524.1000)]

Rick, I can not deal specifically with Han's model. Model based control  
does work.

A very easy example is satellite tracking antennas. The antenna is, of  
course, controlled to a position with a very good closed loop negative  
feedback control system. The reference for this antenna position however  
is generated by a model and in some systems, automatic correction to the  
model takes place.

Obviously, should some unanticpated disturbance to the satellite's orbit  
occur, the model's ability to track would either be completely destroyed  
or seriously impaired depending upon the effectiveness of the feedback  
provided by the "correction" system.

Such almost completely open loop control methods probably do not exist at  
all in living systems. However, we do "control for" things for which we  
have limited immediate perception. In most (but maybe not all) cases, it  
is likely that we model as set of discrete immediate perceptions that if  
achieved \_may\_ achieve the goal (I presume that at the lower or at least  
lowest levels of control ALL perceptions are controlled with negative  
feedback).

Maybe another way of saying what I am trying to express is that when I  
drive over to someone's house to see them, I am controlling perceptions  
using closed loop negative feedback control to full time but the  
perception of meeting someone that is the ultimate control reference for  
the whole series is "open loop" and model based.

-bill