In the text bellow….
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From: Martin Taylor [mailto:mmt-csg@mmtaylor.net]
Sent: Friday, November 04, 2016 6:27 PM
To: csgnet@lists.illinois.edu
Subject: Re: VS: Perceptual Control Theory Talk
[Martin Taylor 2016.11.04.12.52]
[from eetu pikkarainen 2016-11-04]
Dear Boris
Thank you very much for this detailed and very helpful reply!
Now I think I see it quite clearly that the focal point of control is the comparator. It is in a way the deepest core of the subject organism.
I would say rather that the focal point of control is the entire loop, no one part of the loop. Control is what in English we call an “emergent property” of the loop. The comparator is indeed a key point in a loop, but only because the reference value (toward which the controller moves the perceptual value) could be variable. If the reference value is fixed, as is the case at the top level of the hierarchy,
HB : Sorry Martin I don’t get this one. How the reference value in the case of the top level in the hierarchy is fixed. Can you show me in diagram p.191 B:CP (2005) how it become fixed ?
MT : ….no comparator is required but the loop still controls the perceptual value.
HB . How can control function without comparator ? Are you saying that there are processes in nervous system that function without neurons ? There could be signals that »go« beside neurons ? Do you have any examples ? How than control loop look like without comparator ? Or there is some misunderstanding…
MT : With a simple “wire” connecting the perceptual function output to the Output Function input, the loop would still control the perceptual value if the Output Function did the necessary sign inversion to ensure that the feedback is negative.
HB : What could be simple »wire« in nervous system ? Can you give me some examples how this works in nervous system ?
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I think that the problem of “input quantity” (q.i) is connected to the problem of the borderline between the subject and environment. Once we had a professor of psychology who was quite desperately aspiring a scientific breakthrough or even revolution with his theory that there is no borderline at all. And in deed the borderline is problematic. When you wrote that “We control our perception not limbs.” I got an amusing thought that our limbs are in our environment. The border between me and my environment is not the skin but it is somewhere near my nerves - and my bones are already outside in the environment.
In PCT, the word “environment” has many meanings. To be precise, you have to say what the environment is of. Is it the environment of the person (observable to other people) or the environment of the single controller. The environment of the single controller includes all the control hierarchy below its own level. It sends its output directly to its environment, and receives input to its perceptual function directly from its environment – the perceptual signals produced by lower-level perceptual functions. So your “amusing thought” is correct from the point of view of a controller of, say, the relationship between the rim of a cup and your lips when you want to drink.
Controlling takes place inside the organism
No. Controlling takes place in a loop, and only in a complete loop.
HB : You said before that :
MT : With a simple “wire” connecting the perceptual function output to the Output Function input the loop would still control the perceptual value if the Output Function did the necessary sign inversion to ensure that the feedback is negative…
HB : This is not a complete loop…but you said it before it controls ?
MT : We talk about a controller (Perceptual Input Function, Comparator, and Output Function) within the organism, but it does not control anything without its environmental feedback path.
HB : Which environmental feedback path you have in mind ?
Some primitive organisms doesn’t have outside environmental feed back path but they still survive. Succesfull controlling in organism is the first step to survive, whether external feed-back (in organisms they posses it) is used depends from organisms state of homeostasis which is genetically determined.
When you are sunshining or sleeping you don’t use external feed-back path but still you control succesfully inside…Most control is done inside organism. External feed-back path is just used when internal control subsystems can not control internal environment to genetically set reference conditions. But until you control succesfully inside you will not use outside effectors…
This is something that Bruce Abbott quite good described in his Synopsis :
BA : At the heart of perceptual control theory is the idea that human beings are essentially intricate control mechanisms that function to keep certain intrinsic (or essential, see Ashby, 1952) variables within survivable limits. Intrinsic variables (variables intrinsic to the organism) include basic physiological variables such as blood glucose levels or body temperature, as well certain high-level variables whose maintenance in certain states are crucial to the individual’s well-being; the references of these intrinsic variables are genetically specified. With respect to physiological quantities, the body is known to house numerous control mechanisms that help to maintain them within the narrow limits required for efficient operation and survival. These mechanisms are capable of sensing the current levels of these controlled quantities and automatically initiating physiological changes as necessary to correct deviations of these levels from reference values, a process that the early 20th century physiologist Walter Cannon (1932) termed homeostasis.
BA : Although at any given moment a tremendous number of physiological quantities is being automatically regulated through nonbehavioral (purely physiological) means, the regulatory mechanisms by themselves are not capable of countering all the sources of potential disturbance to the intrinsic variables. To take one example, because humans are not rooted in the soil like plants, we must seek out and consume food and water. Automatic physiological mechanisms do act against disturbances to internal levels of water and nutrition, but these only can take the form of actions to reduce the rate of depletion of these quantities. To replenish them, we must behave. That is, we must move our muscles in a way that ultimately leads to locating, obtaining, and consuming food and water. Behavior, then, is a means by which humans (and other animals) defend their intrinsic variables against disturbance.
Boris
and the functions form the multilayered and permeable borderline between the organism and its environment. Thus we could think that there is something x in our environment (which may be somehow important to the organism like food, or danger) and it causes a causal effect to a receptor of the organism. Now that effect IN the receptor is the input quantity (q.i). (The quantity of q.i does not depend on the quantity of the x, but rather on the strength of the physical interaction between x and the receptor.) In the receptor the input function produces the perception signal § which is not same as q.i but a quantitative analog of it.
Correct.
BTW It seems that there is a problem (for me) in that LCSIII diagram which you copied (I have not yet got the book) and which you describe as “But »input quantity« in general sense represent effects of disturbances or effects of behavior or both.” I think there must be something else too. If I sleep and perceive the comfort room temperature (say +20C) I wouldn’t say that this input quantity consists only of effects of disturbances and/or effects of behavior.
No. It is a reference input, not a perceptual input. You are saying that 20C is comfortable, while lower is too cold and higher is too hot. The perceptual value is the actual temperature, as transformed by your nervous system. It is influenced by things like your actions (setting a thermostat, opening or closing a window, moving to get into or out of a draft, and so forth) and by disturbances from the environment (passage of a cold front, increasing wind, etc.). There isn’t any “something else” because all the possible effects are included in “what I do” (my behaviour) and “what happens that I don’t cause” (the disturbance).
If the temperature went higher or lower, then I would call it disturbance and it would perhaps require some behavior form my side.
In PCT terms, it would be not a disturbance, since all the effects not caused by you are caused by something outside, and all combine to form “the disturbance”. You are talking about a change in the disturbance, which “would perhaps require some [change in] behaviour from my side”.
Probably this is only a question of vocabulary, but I would differentiate those effects of environment which do (via mediation of p) cause an error signal from those which do not, and call only the first case disturbance.
Then it is a question of vocabulary. The error signal is always there, whether its value is zero or any other value. Zero error does not mean no behaviour. All it means is that so long as the disturbance doesn’t change and the effect of your behaviour on the input quantity doesn’t change, your perception will remain as you want it to be.
If there is a disturbance then the output effect will cancel it by altering the input quantity but that does not mean that this output effect would remove the input quantity altogether, does it?
No it doesn’t. It just brings the input quantity to a value that creates the perceptual value that matches the reference value.
Martin
Best regards
Eetu Pikkarainen
Lähettäjä: Boris Hartman boris.hartman@masicom.net
Lähetetty: 4. marraskuuta 2016 8:05
Vastaanottaja: csgnet@lists.illinois.edu
Aihe: RE: Perceptual Control Theory Talk
Dear Eetu.
I answered in your text bellow….
From: Eetu Pikkarainen [mailto:eetu.pikkarainen@oulu.fi]
Sent: Thursday, November 03, 2016 8:27 AM
To: csgnet@lists.illinois.edu
Subject: VS: Perceptual Control Theory Talk
Hi Vyv, thank you for this hint. I see that this last book of Powers is really something to read and I will order it.
Eetu Pikkarainen
Lähettäjä: Huddy, Vyv v.huddy@ucl.ac.uk
Lähetetty: 2. marraskuuta 2016 15:08
Vastaanottaja: csgnet@lists.illinois.edu
Aihe: RE: Perceptual Control Theory Talk
[Vyv Huddy 1247.02.11.2016]
Hi Eetu,
Just sharing an experience of learning about PCT. Carefully reading B:CP has helped but, looking back, I would have learned about PCT more quickly if I’d started with the book Living Control Systems III. If you are not already aware this book comes with a selection of demonstrations that run on a PC. The parameters of the demonstrations can be adjusted and the effect of these adjustments can be observed and experienced. This is important because the experience of seeing control happening, and recognising it as such, is key to opening the window on understanding it. For me at least!
All the best,
Vyv
From: Eetu Pikkarainen [mailto:eetu.pikkarainen@oulu.fi]
Sent: 31 October 2016 09:41
To: csgnet@lists.illinois.edu
Subject: VS: Perceptual Control Theory Talk
[from eetu pikkarainen 2016.10.31]
Dear Boris,
Thank you for your relentless criticality, I really appreciate such.
As a newcomer I have problems to follow and find the most essential points – even though I am in a process of re-reading B:CP (in the middle of doing much else). You wrote:
“Rick is definitelly promoting RCT, where »behavior is control«, there is some »controllled variable« in environment and there is some kind of »Controlled perceptual variable« in afferent nerv going to afferent neuron (comparator). There is no such things in PCT.”
HB : Ricks’ terminology show that »control« is something that is happening in environment. So he is putting all the time »controlled variable« into organisms environment in PCT diagram what is not the case with Bill. Rick tried many times to make it »official« and I don’t understand how he didn’t succed, because he has Powers lady in his »pocket«. Whatever. PCT is still as it was although Rick is desperately trying to change it with his »Behavior is control« and »controlled variable« etc.
Bill is not putting »controlled variable« in the environment in the sense that »control« is happening in organisms environment. At least in diagram LCS III. Bills’ defitnion of »control« is clear (mostly from B:CP) :
![cid:image001.png@01D23600.98B1E160]()
Bill also mentioned many times that PCT is about how organisms control.
EP : I understand that 1) behavior (doings) are not controlled and 2) things in the environment are not controlled, but the third issue is problematic to me. I have understood that it is just the perception i.e. the variable called p i.e. the neural signal created in receptor(s) and transmitted to comparator, which IS controlled. Have got it wrong?
HB : You understand right, that behavior (output) is not control or process of control, so that something or anything in the environment is controlled. Bill is mostlly (99%) using word »affect«, what I think actually happens in the environment of organism. So yes things in environment if they exist are not controlled but affected. And yes to 3). Only Perceptual signal will be directly »controlled« and that’s why it’s called »controlled variable«.
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So we see that in this Bill’s definition there is no control and if you will read Glossary in B:CP nowhere in other definitions Bill mentioned anything about »behavior is control« except in term »controlled quantitty« which I answered in conversation between Rick and Martin.
Things in environment are not controlled, because behavior is not control, and there is no »controlled variable« in environment in GENERAL sense that SOMETHING will be controlled by behavior. Important is that we stick to GENERAL SENSE of PCT so how organisms generaly control. And that is the diagram in LCS III showing clearly.
There is not always (continuously) present something in environment that behavior could control (reduce discrepancy). Generally speaking output (behavior) is used for affecting input and also for canceling the effects of disturbances.
Bill P (LCS III):
FEED-BACK FUNCTION : The box represents the set of physical laws, properties, arrangements, linkages, by which the acrtion of this system feeds-back to affect its own input, the controlled variable. That’s what feed-back means : it’s an effect of a system’s output on it’s own input.
HB : Mostly behavior if you will observe yourself don’t have anything special in environment that is »manipulated« by behavior, as behavior is not process of control in general sense. We don’t dig a cup of coffee with our hands or eat with moving (controlling the movement) of our hands or that we move legs while we are walking and so on. That is self-regulation theory. And Rick is supporting it all the time. He is afterall psychologist like for example Carver and Scheier (the authors of selfregulation theory based on PCT). When I was mediating between Bill and Carver, Bill told me that they were his students what their book from 1981 prove.
But I think that »controlled quantitty« which could be present in »environment of organism« will sooner or later become part of perceptual signal, which is controlled variable (will be matched with reference in comparator). And this is the only place where by my oppinion control is happening. Comparator is not a function in the sense all other boxes in diagram are. So it’s the only place where control can happen (nervous system).
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Comparator present one neuron or the whole nervous system. I think that all controlling is done in nervous system. I don’t see any place in control loop that control can be done. Specially not in environment of control system. And perceptual signal is the »controlled variable« which enters comprator. I think it’s obvious.
The result of control is »error signal«.
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Here it seems that Bill was equating »Controlled quantitty« with »perceptual signal«. It could be equated with »input quantitty« although from diagram in LCS III is not clear that »controlled quantitty« exist in any general sense. But »input quantity« in general sense represent effects of disturbances or effects of behavior or both. Bill wanted to create a theory that would generally answer the question how organisms generally control.
In the environment (LCS III diagram) there are present effects of disturbances and effects of behavior (output) added. For disturbances we can assume that they are always present (hit, radiation of all kinds, sun, etc.), but effects of behavior (ouptut) are present more or less discreetly.
For example in sleeping, what Rick correctly described as »tough one«, existance of »input quantity« in environment, doesn’t have any effects of behavior (output) that would by definition of control also cancel the effects of disturbances. Disturbance in sleeping for ex. is temperature of the room that is affecting organisms control. In this case »input quantitty« contain just »effects of disturbances« and no counter effetcs of behavior (output) that could be present in environment. So there is no »controlled quanttity« in outer environment as Rick is trying to present as general principle. But organism is still controlling. The body temperature in accordance with room temperature is controlled (ex. 36,8). So there are »controlled quantities« in organism and »controlled process« in organism that are always present in if you look at definition of control above. So control in organism in general sense is present 24/7 as Bob Hintz denoted this process. I think he is momentaly one of those who also understand PCT in the sense of my explanation and according to Bills’ definitions.
EP :
The whole concept of “control” is difficult me because of the different theoretical background and also the language: If I try to tell shortly to some of my fellow citizens about my newly found theoretical inspiration, I have the first trouble how to translate the name of PCT in Finnish! I believe many other outsiders have similar problems. And for you insiders the question may seem so self-evident that it is hard to explain / narrate understandably? Sometimes I feel like I had understood the whole idea perfectly and then again I am totally confused.
HB :
Beleive me dear Eetu the same thing happened to me. When i was trying to understand PCT I thought that I’ll finish in »mental hospital«. My first »teacher« was Kent (his »papers« on internet and some meils in 1999). His language is quite clear and understandable, but i thought that the word of author of PCT will reveal to me all »secrets« of PCT. And than troubles began because Bill’s sicentific language in his LCS chain of books is hard to understand for the begginer. I have to consult with Bill but in the beggining I didn’t understand even his explanations and I was confused as you are now. Then I found Bruce Abbotts’ synopsis. You can get it on this page http://users.ipfw.edu/abbott/pct/pct.html. I also returned to Kent and his »papers«. And the »light« above my head start slowly to shine. After all these first difficulties which happened in 6 years I take a break and than one day I started the talk with Rick Marken. Well Rick (somewhere in 2007) in the beggining understood PCT and as I described many times our converstaion started with which »perception do we control« and not which »controlled variable« we are controlling in environment. So I don’t understand where Rick was lost, but he is totaly out of PCT line. After that I talked a lot also with Martin and wrote on ECACS. I talked also to Kent and some other PCT’ers. I talked also a lot with Bill whom I finaly understood with no problem.
All in all it took me quite long time to understand PCT. Maybe you could try with the same literature and members I did. But I strongly advise that you don’t try with Rick. He is a confussion maker because his RCT is contrary to PCT and he has »power« because Powers ladies are fully supporting him (see Barbs’ message). They took me half of my health in last years to keep CSGnet close to PCT. But I don’t know how long will I persist. Rick is coming with new manipulations and seeking through Bills’ literature to find appropriate answer is not easy job. Anybody can try it.
EP : So how would you define shortly for a newcomer what does the “control” mean? What is it what is controlled and how? Does controlling take place in a certain place or stage of the closed loop? Or is control rather a function of the whole loop?
HB : I hope dear Eetu, I described you shortly what »control«, »control system«, »ouptut«, »feed-back«, and so on mean through Bills’ definitions. I think this is only fair approach to hear the »sound« of author. It’s refreshing among all other oppinions. Isn’t it Barb ?
I hope that I manage to present you also what »controlled quantity« and »input quantity« could mean. Problem is that Bill did changed his mind sometimes but Rick is a World Champion. He is changing his oppinion sometimes daily, weekly, monthly…. Also constant in his oppinion is Kent with his concept of »stability«. It’s PCT. Martin was very stable when Bill was with us. As I understood him he was quite often communicating with Bill. But now I think that he is too much communicating with Rick and he started to »fluctuate« like him. And he was so stable and perfect in PCT understanding. Rick can cause a lot of troubles in understanding of PCT because he is just relaying on his experiences which can be misleading as he can observe his behavior as control of limbs. It’s common psychological approach. It’s common sense reasoning. But Bill showed it’s wrong. We control our perception not limbs. Rikcs’ »cancer point« are his demos and tests, because he thinks that he will understand PCT through them. But as Bill said, the final arbiter is nature. So we should learn there. Experimenting in nature. And I noticed that Rick could be going that way if I may conclude from his latest experiment with Warren. I hope he will continue his nature experimental work as this is the way to understand PCT.
EP : (And apologies beforehand if I will make follow-up questions.)
HB : As I mentioned mayn times I’m in troubled life position and I don’t have always time. But I’ll answer sooner or later J
Best,
Boris
Eetu Pikkarainen
