The speed�?curvature power la w of movements: a reappraisal

Alex,

I really admire your work and your scientific efforts. But let us consider what is contribution of Power Law to any other science or to human efforts to understand how organisms function or even how nervous system function.

I think that calculating the trajectory and speed of behaviors (if I understood right what Power Law ia bout) has to have some purpose. PCT has obvious purpose. To understand how orgsnisms function and specialy to understand how nervous system function, and how produce behaviors. What is real purpose of Power Law ? How does it contribute to understanding how organisms function. Or nervous system function when it’s producing »curvature« behaviors ?

I think this would be normal contribution to world human knowledge. At least I see it this way.

What are you expecting that Power Law will explain ? That all behaviors will fit in some equations which are get from observed behaviors ? It seems that psychology (I’ll call it the science about behavior) wanted for a long time to conclude from analyzing  observed behaviors to get some general rules which could explain future behaviors in certain circumstances. So it look like that environment is the most important to what behavior will occur. But »old« psychology can’t explain behavior correctly.

PCT showed where »old« psychology was wrong. For now I don’t know for any theory that could explain better how organisms function and how nervous system function and how it’s producing behavior. Do you think that Power Law explains better what PCT explores ?

Boris

···

From: Alex Gomez-Marin [mailto:agomezmarin@gmail.com]
Sent: Tuesday, October 31, 2017 5:01 PM
To: Alex Gomez-Marin; csgnet@lists.illinois.edu
Subject: Re: The speed�curvature power law of movements: a reappraisal

regardless of your helicopter data and RCT mantras, it would be good if someone from CSGnet took seriously the challenge to PCT that the speed-curvature power law entails.

any figure panel of our paper proves rick’s mathematical claims wrong: the PL is not a must and when it takes place it is not trivial and can have different exponents.

now, how can “control of perception” explain that phenomenon? claiming it is an illusion because it does not fit in the dogma is like creationists insisting that dino fossils are bogus.

so, as adam and myself take this job seriously, and given how many optimal control and nonPCT theories explain the data, I think Bill would really find his edifice crumbling, or at least unable. so, take your best shot at it and really challenge your “revolutionary paradigm changing” theory of behavior.

On Sun, 29 Oct 2017 at 02:48, Richard Marken rsmarken@gmail.com wrote:

[From Rick Marken (2017.10.28.1745)

On Sat, Oct 28, 2017 at 3:34 PM, Alex Gomez-Marin agomezmarin@gmail.com wrote:

attached

RM: Finally! Thank you, Alex. I hope the journal gives us an opportunity to respond. But for now I have only one word for you: helicopter movements. Oh, that’s two words But you know how bad I am at math;-)

Best

Rick

Richard S. Marken

"Perfection is achieved not when you have nothing more to add, but when you
have nothing left to take away.�
–Antoine de Saint-Exupery

Alex Gomez-Marin
behavior-of-organisms.org

Down ….

···

From: Richard Marken [mailto:rsmarken@gmail.com]
Sent: Wednesday, November 01, 2017 6:15 AM
To: csgnet@lists.illinois.edu
Subject: Re: The speed�curvature power law of movements: a reappraisal

[From Rick Marken (2017.10.31.2215)]

On Tue, Oct 31, 2017 at 9:01 AM, Alex Gomez-Marin agomezmarin@gmail.com wrote:

AGM: regardless of your helicopter data and RCT mantras, it would be good if someone from CSGnet took seriously the challenge to PCT that the speed-curvature power law entails.

RM: What challenge? PCT explains it quite nicely as a mathematical property of curved trajectories. This fact explains why it appears as a side effect of intentionally produced curved movement… But apparently no one else on CSGNet sees it that way so your paper has demonstrated to me that no one on CSGNet (no one who posts, anyway) understands PCT. At least, they don’t understand it the way I do. This has convinced me that I must withdraw my Preface to LCS IV because I can’t in good conscience say that the papers in that book will be based on Powers’ theory and, thus, honor his legacy.

HB : Good that you’ll withdraw your Preface. This is the way to preserve Powers theory. With not contributing RCT to any published literature.

AGM: any figure panel of our paper proves rick’s mathematical claims wrong: the PL is not a must and when it takes place it is not trivial and can have different exponents.

RM: There is nothing in your paper that proves that any of the claims made in our paper are wrong. We will explain this all in our own “reappraisal” of your “reappraisal”. But for now I’ll just say that our paper didn’t say that the power law was trivial; it showed that the power law is an illusion in the sense that it looks like it is relevant to understanding how organisms produce movement when it is not.

HB : Maybe I could agree with you about the way »Power Law« was presented till now. It seems that it can’t explain how organisms function. Or even how nervous system function. And how by your oppinion organisms produce movements ??? With independent control units like you described in your artcile about »Power Law«. If I compare the »nothing« explained about how organisms function by your example of »helicopter« and »Power Law« I’d say that »Power Law« include less of »nothing« than your example with helicopter. It’s worse. Helicopter example shows »stimulus . respons«. People move in accordance to movement of helicopter. Where did you see this in reality ? Amd this should be the case of »purposefull behavior«.Â

RM : Nor did we say that the power law can’t have different exponents; in fact we showed precisely why you do find different exponents for the power law; it’s because you omit a variable from the regression analysis used to determine that exponent.

AGM: now, how can “control of perception” explain that phenomenon? claiming it is an illusion because it does not fit in the dogma is like creationists insisting that dino fossils are bogus.

RM: No, we say it is an illusion because it is demonstrably a side effect of controlling perceptions, as demonstrated by the model of toy helicopter pursuit that we present in the paper (and that you simply dismiss as wrong for no apparent reason other than that it just must be).

HB : As I said above. You demonstrated with helicopter example that »environment is controlling« people movement. You proved simple »stimulus-respons« theory. There is no »purposefull« behavior in your example  so that we could answer the question how people decide for their behaviors. In your case people »decide« to move along with helicopter movement probably because they were told to do so. How will you understand from this example how people form purposefull behavior.

And your assunption is that they produce purposefull behavior with two independent control units. Is this how nervous system function ? Is this a joke ?

AGM: so, as adam and myself take this job seriously, and given how many optimal control and nonPCT theories explain the data,

RM: I have not seen any control models that explain the data; the term “controlled variable” is not to be found anywhere in your paper or in any other papers I have read in the area. The models I have seen that “explain” the power law are all output generation models – what Powers called “curve fitting” models – that would fail completely if they had to account for the fact that the observed curved movements being modeled are produced in a disturbance prone environment; the curved movements are themselves controlled variables.

HB : Behavior itself is a »controlled variable« ? How organisms produce »controlled behavior« ?

AGM: I think Bill would really find his edifice crumbling, or at least unable. so, take your best shot at it and really challenge your “revolutionary paradigm changing” theory of behavior.

RM: I think you are right about that. If Bill has been listening in on CSGNet for the last 4+ years he would, indeed, see his revolutionary paradigm crumbling.

HB : You are the one that contributed most of it.

I knew that people would disagree with me as much as they did with Bill

HB : Who said that Bill agreed with you ? He did protect you. But at least once you tryed to aline your and his knowledge and he answered in clear »no«. Your and Bills’ knowledge are not aligned. Anyway you show in every post disalignment with his literature.

RM : ….bbut I was surprised by the intensity and meanness. But I know there are one or two people out there (not on CSGNet) who not only agree with my understanding of PCT (which I’m pretty, pretty, pretty sure is the same as Bill’s) but are also doing excellent PCT research.

HB : I’d really like to meet these two people who don’t understand PCT ? You don’t understand PCT. And you never will.

RM: It’s too bad; I really thought you really considered PCT a possible explanation of the power law. I guess my trusting nature got the football pulled away from me again. You are obviously very talented at research. It would have been great to have you working on doing research based on an understanding of PCT. But, alas, I guess it’s not to be.

HB : I agree that it would be good for people to use PCT. but not RCT.

Boris

Best

Rick

On Sun, 29 Oct 2017 at 02:48, Richard Marken rsmarken@gmail.com wrote:

[From Rick Marken (2017.10.28.1745)

On Sat, Oct 28, 2017 at 3:34 PM, Alex Gomez-Marin agomezmarin@gmail.com wrote:

attached

RM: Finally! Thank you, Alex. I hope the journal gives us an opportunity to respond. But for now I have only one word for you: helicopter movements. Oh, that’s two words But you know how bad I am at math;-)

Best

Rick

Richard S. Marken

"Perfection is achieved not when you have nothing more to add, but when you
have nothing left to take away.�
–Antoine de Saint-Exupery

Alex Gomez-Marin
behavior-of-organisms.org

Richard S. Marken

"Perfection is achieved not when you have nothing more to add, but when you
have nothing left to take away.�
–Antoine de Saint-Exupery

[From Bruce Abbott (2017.11.01.0945 EDT)]

[From Rick Marken (2017.10.31.2215)]

···

On Tue, Oct 31, 2017 at 9:01 AM, Alex Gomez-Marin agomezmarin@gmail.com wrote:

AGM: regardless of your helicopter data and RCT mantras, it would be good if someone from CSGnet took seriously the challenge to PCT that the speed-curvature power law entails.

RM: What challenge? PCT explains it quite nicely as a mathematical property of curved trajectories. This fact explains why it appears as a side effect of intentionally produced curved movement… But apparently no one else on CSGNet sees it that way so your paper has demonstrated to me that no one on CSGNet (no one who posts, anyway) understands PCT. At least, they don’t understand it the way I do. This has convinced me that I must withdraw my Preface to LCS IV because I can’t in good conscience say that the papers in that book will be based on Powers’ theory and, thus, honor his legacy.

BA: You can resolve this controversy yourself quite easily. Next time you are on campus, stop by the Mathematics Department and ask a faculty member who is competent in analytical geometry to review the mathematical basis of your paper. Be sure to give this person both your disputed paper and the Gribble and Ostry (1998) paper from which you get the equations you rely on.

BA: The dispute is not with PCT, it is about the soundness of your mathematical analysis. It is obvious that the power law is a side-effect of controlling certain variables – neither people nor larrvae are controlling for moving in conformance with the power law. But contrary to your belief, the power law is not a mathematical property of curved trajectories, and therefore cannot “explain why it appears as a side effect of intentionally produced curved movement.â€? It follows that the emergence of the power-law relation during curved movements remains to be explained. Developing a PCT explanation will require applying the test for the controlled variable.

BA: So again, I encourage you – indeed implore you – to submit your ur analysis (and its context) to a mathematician on campus for review. You may not be happy with the result, but at least you will learn why so many of us on CSGnet have been asserting that your mathematical analysis of the power law is unsound. What have you got to lose?

Bruce

Dear Eetu

···

From: Eetu Pikkarainen [mailto:eetu.pikkarainen@oulu.fi]
Sent: Wednesday, November 01, 2017 10:47 AM
To: csgnet@lists.illinois.edu
Subject: RE: The speed�curvature power law of movements: a reappraisal

[Eetu Pikkarainen 2017-11-01]

(at the risk to be ridiculed…)

I should be but as a humanist, I try not to be ashamed because of missing mathematical competence. I practice my understanding by composing a non-mathematical description of what is going on in this case of PCT and Power Law.

When a living being is producing a movement trajectory by moving itself (e.g. crawling) or its organs (e.g. hand in a drawing task) there seems to be a certain dependence between the curvature of the trajectory (proceeding straight or turning to some direction) and the speed/velocity (understood here as a moved distance along the trajectory during a time unit). The normal case is that the speed is stable on the straight line but it slows down in a curve.

Now the first question is why that slowdown in the curve takes place. The second question is why the dependence between curve and speed has those certain values, which have been observed in different situations. That latter question will be postponed.

EP : PCT view is generally that the behavior of an organism is that it controls its certain perception(s)

HB : Sorry Eetu to not agree with you. It’s not that behavior “controls perception� because behavior can’t be controlled. It just affects input generally. If you are sleeping how you are “controlling� perception with behavior ?

EP : ….by affecting by its output some environmental correlates of those perceptions.

HB : Output can affect some correlates of perception in environment, but it has nothing to do with control in environment. What correlate you are affecting in environment if you are observing. And what correlate you are affecting in environment if you are sitting and thinking ? You just affect input. That’s what “feedback� is.

Bill P (LCS III):

FEED-BACK FUNCTION : The box represents the set of physical laws, properties, arrangements, linkages, by which the action 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 : You put it very efficiently what is important about PCT in other post :

Eetu earlier : I think that when I am telling about PCT it is generally best to start from the idea of self-preservation, that any organism - from the most simple to most complex - must control its intrinsic variables to stay alive. From that I can continue to interaction with environment, the must of affecting and stabilizing things in the environment. Only after that it is possible to start to compare organism to thermostat and draw technical diagrams. Thus it goes from soft and warm to hard and technical.

HB : It’s control in organism that is on first place and behavior just support to control in organism. That’s what Bills’ definition is talking about.

Bill P (B:CP):

CONTROL : Achievement and maintenance of a preselected state in the controlling system, through actions on the environment that also cancel the effects of disturbances.

HB : So you think right that what is important is preselected state in organism which includes »intrinsic variables«. Internal control is of most importance. What happens in outer environment is important but supporting to internal control. Behavior is »fired« from internal environment not external in accordance how internal environment is controlled. This is the function of internal and external effectors. Â

Best,

Boris

EP : So when an organism is moving it can be controlling for its distance from some object to be long (if the object is perceived as dangerous) or short (if the object is perceived as desirable). Any regularities of behavior are often assumed to be side effects of control. (Not side effects of observation.)

EP : At the moment I have no idea what the larvae are controlling in those experiments but introspectively I can imagine some possible perceptions I would control in a drawing task. First, I control seeing me a helpful aid in science making and being an obedient test subject and following to the rules. Then I would control to see the pen moving in a calm and nice way on the paper. At the same time, I control that the pen follows the guiding line as strictly as possible. I think that my output function is such that it is easier to follow a line with certain kind of curvature than with another kind. We humans get much practice to draw just certain kind of lines when we learn to draw and write. But there can also be some more general reasons why we use just those curves in our letters and typical drawings that we use. Anyway, it feels much more natural to draw a circle or looped circles than rounded polygons.

Therefore, the increased difficulty in controlling of the latter perception (following the line) would draw some effort away from the control of the first perception (keeping the steady or moderate speed). Or rather the slowing down the speed will make it easier to control the following the line. (A straight line is easier to draw with higher speed than very slowly.) So the slowdown could be a side effect of control. Perhaps something similar is going on with larvae? Is it easier for them to go straight forward? Is it an additional challenge to turn – to ddecide to turn and not to continue forward? Would the slowdown make it easier to control the perception of the new direction?

Is that at all where the PCT view of Power Law could begin?

Eetu

From: Alex Gomez-Marin [mailto:agomezmarin@gmail.com]
Sent: 31. lokakuuta 2017 18:01
To: Alex Gomez-Marin agomezmarin@gmail.com; csgnet@lists.illinois.edu
Subject: Re: The speed�curvature power law of movements: a reappraisal

regardless of your helicopter data and RCT mantras, it would be good if someone from CSGnet took seriously the challenge to PCT that the speed-curvature power law entails.

any figure panel of our paper proves rick’s mathematical claims wrong: the PL is not a must and when it takes place it is not trivial and can have different exponents.

now, how can “control of perception” explain that phenomenon? claiming it is an illusion because it does not fit in the dogma is like creationists insisting that dino fossils are bogus.

so, as adam and myself take this job seriously, and given how many optimal control and nonPCT theories explain the data, I think Bill would really find his edifice crumbling, or at least unable. so, take your best shot at it and really challenge your “revolutionary paradigm changing” theory of behavior.

On Sun, 29 Oct 2017 at 02:48, Richard Marken rsmarken@gmail.com wrote:

[From Rick Marken (2017.10.28.1745)

On Sat, Oct 28, 2017 at 3:34 PM, Alex Gomez-Marin agomezmarin@gmail.com wrote:

attached

RM: Finally! Thank you, Alex. I hope the journal gives us an opportunity to respond. But for now I have only one word for you: helicopter movements. Oh, that’s two words But you know how bad I am at math;-)

Best

Rick

Richard S. Marken

"Perfection is achieved not when you have nothing more to add, but when you
have nothing left to take away.�
–Antoine de Saint-Exupery

Alex Gomez-Marin
behavior-of-organisms.org

Martin,

MT : So the first step is to propose some plausible perception(s) that might be being controlled, and then try to disturb them to include or exclude them from the plausible list. If a perception of the power-law relationship and the particular exponent is implausible, then the power-law itself is a side-effect of control, and the problem becomes one of explaining what environmental conditions affect the perception and the action influence on whatever is being controlled.

HB : It seems that you are back Martin ? This is pure PCT description not RCT.

MT : Enough philosophy of science. It would be nice to be able to figure out what controlled perceptions

HB : What is »controlled perception« ?

MT : ….in what environmental circumstances leead to power laws, and with what exponents when power laws are found. Incidentally, has anyone ever analyzed movies of a skater doing school figures? It is my impression that their skates move faster along the ice when the curvature is high (low radius of curvature), but that may be an illusion.

Boris

···

From: Martin Taylor [mailto:mmt-csg@mmtaylor.net]
Sent: Tuesday, October 31, 2017 11:02 PM
To: csgnet@lists.illinois.edu
Subject: Re: The speed�curvature power law of movements: a reappraisal

[Martin Taylor 2017.10.31.13.35]

On 2017/10/31 12:01 PM, Alex Gomez-Marin wrote:

regardless of your helicopter data and RCT mantras, it would be good if someone from CSGnet took seriously the challenge to PCT that the speed-curvature power law entails.

Yes, but that includes your team, too. A long time ago I suggested a start to seeking possible controlled variables in different conditions. You said you would try some. Have you?

any figure panel of our paper proves rick’s mathematical claims wrong: the PL is not a must and when it takes place it is not trivial and can have different exponents.

True.

now, how can “control of perception” explain that phenomenon? claiming it is an illusion because it does not fit in the dogma is like creationists insisting that dino fossils are bogus.

So far as I am aware, only Rick’s bogus mathematics has led anyone on CSGnet even close to saying such a thing.

so, as adam and myself take this job seriously, and given how many optimal control and nonPCT theories explain the data, I think Bill would really find his edifice crumbling, or at least unable.

Why, if none of the obvious tests have been done?

so, take your best shot at it and really challenge your “revolutionary paradigm changing” theory of behavior.

First, let’s define the challenge. You have a considerable body of observations that relate some environmental states to a power-law relationship between local curvature of a track followed by (including produced by) organisms in motion and the tangential velocity of movement along the track. You also have conditions under which the relationship is not followed. What are the essential differences among these conditions? Is the challenge for PCT to predict/explain that? Or is it in general to explain why power laws are observed sometimes and not other times? PCT does offer a generic explanation for the observation of power laws, which Bill and Rick used to explain the Stevens power law for perceived (reported) sensory magnitudes. It is that a power law will result when a perception is controlled of a relationship between two perceptions that have a near-logarithmic relation to their relevant magnitudes. In this case, maybe the challenge resolves into discovering the two perceptions in question. Might that be true? Or is this particular power law not an example of the generic case? Maybe that’s the challenge.

If you are going to assert that PCT is “unable” to explain any data, whatever the experiment, you first have to seek a controlled variable. It is highly unlikely in any of the conditions of any of the experiments that the mover controlled a perception either of following a power law relation between speed and curvature, and even if they did, that they were controlling for making the exponent take on some particular value. So the first step is to propose some plausible perception(s) that might be being controlled, and then try to disturb them to include or exclude them from the plausible list. If a perception of the power-law relationship and the particular exponent is implausible, then the power-law itself is a side-effect of control, and the problem becomes one of explaining what environmental conditions affect the perception and the action influence on whatever is being controlled.

A perceptual variable that is available to larvae and to humans would naturally be more plausible than a requirement that different species control different variables but wind up with the same results. But it may prove that several different perceptual controls working through similar environmental constraints would all give the same power law. A power law is, after all, the result of subtracting one logarithm from another, and since most perceptions do seem to have a near logarithmic relation to the relevant environmental variable (Weber-Fechner Law), such a result is not too far-fetched to contemplate.

Whatever the controlled variables might be, difficulty in finding them is not the same as proof that they do not exist, or that PCT is a crumbling edifice. It helps if the search has been at least begun without successful conclusion, but such searches sometimes take thousands of years. Ptolemy’s laws explained the planetary motions relative to the starts well enough not to be discarded for a thousand years, within one conceptual frame – Earth-centred Universe. Kepler and Newton provided a better explanation, and that was good enough in a different conceptual frame – a Universe conceptually known synoptically by an omniscient being. But it had little niggles in it such as the advance of the perihelion of Mercury. Einstein came up with a better explanation in a third conceptual frame – “what you see is what you get” (relativity), but it also has niggles in its incompatibility with quantum chromodynamics, so I guess the next advance is a fourth conceptual frame yet to be found.

PCT is, I think, in the relativistic conceptual frame – “what you perceive is what you get”. Earlier theories that base behaviour strictly on the environment are in the Newtonian conceptual frame “You would know it all if you were God”. As with Ptolemy-Newton or Newton-Einstein, the earlier and older theories explain the data pretty well, because that’s what they are designed to do. In each case, the newer theory explained a wider range of data and explained it more accurately because it started from “why”, not “what”. Newton’s “why” for the planetary motions was the gravitational law that produced Kepler’s ellipses, which were a descriptive improvement on Ptolemy’s epicycles. Einstein’s “why” for Newton’s gravitational law was the distortion of space-time by mass-energy. I suppose the next conceptual revolution in that area of physics will be the finding of a “why” for space-time deformation that resolves the problems with quantum theory. One “why” is simpler than a whole lot of “whats” in the Occam’s Razor sense.

PCT offers a relativity-level “why” for a whole mass of data that is observed and for which many people have provided Ptolemy or Newton-level “what” explanations. Maybe optimal control theory does, too, but PCT has the advantage of not having to do complex computations of such things as joint angles and of not having to make special provision for the effects of unexpected external events and forces, since dealing with them is built into the structure. I am not aware of optimal control theory having been applied to sociology, but I suppose it must have been. However that may be, I suspect that another change of conceptual framing will someday provide a “why” for the “whats” of PCT, further simplifying science as a whole.

Enough philosophy of science. It would be nice to be able to figure out what controlled perceptions

HB : What is »controlled perception« ?

in what environmental circumstances lead to power laws, and with what exponents when power laws are found. Incidentally, has anyone ever analyzed movies of a skater doing school figures? It is my impression that their skates move faster along the ice when the curvature is high (low radius of curvature), but that may be an illusion.

Martin

On Sun, 29 Oct 2017 at 02:48, Richard Marken rsmarken@gmail.com wrote:

[From Rick Marken (2017.10.28.1745)

On Sat, Oct 28, 2017 at 3:34 PM, Alex Gomez-Marin agomezmarin@gmail.com wrote:

attached

RM: Finally! Thank you, Alex. I hope the journal gives us an opportunity to respond. But for now I have only one word for you: helicopter movements. Oh, that’s two words But you know how bad I am at math;-)

Best

Rick

Richard S. Marken

"Perfection is achieved not when you have nothing more to add, but when you
have nothing left to take away.�
–Antoine de Saint-Exupery

Alex Gomez-Marin
behavior-of-organisms.org

[From Bruce Abbott (2017.11.01.2140 EDT)]

Rick Marken (2017.11.01.1720)]

Bruce Abbott (2017.11.01.0945 EDT)–

RM: What challenge? PCT explains it quite nicely as a mathematical property of curved trajectories. This fact explains why it appears as a side effect of intentionally produced curved movement… But apparently no one else on CSGNet sees it that way so your paper has demonstrated to me that no one on CSGNet (no one who posts, anyway) understands PCT. At least, they don’t understand it the way I do. This has convinced me that I must withdraw my Preface to LCS IV because I can’t in good conscience say that the papers in that book will be based on Powers’ theory and, thus, honor his legacy.

BA: You can resolve this controversy yourself quite easily. Next time you are on campus, stop by the Mathematics Department and ask a faculty member who is competent in analytical geometry to review the mathematical basis of your paper. Be sure to give this person both your disputed paper and the Gribble and Ostry (1998) paper from which you get the equations you rely on.

RM: I wrote the power law paper and submitted it for publication in EBR because I felt that my mathematical/statistical analysis was correct and the criticisms I was getting on the net in our net discussion over a year ago were wrong. I thought that if the paper were accepted in a peer reviewed journal – the very journal where much of the research on the power law is published – that might convince you that your criticisms of my analysis were themselves wrong. And the paper was reviewed and accepted for publication and the result was that the criticisms became even more earnest. So I don’t think that getting my paper reviewed by someone in the Math department is going to help. But I actually did have a senior researcher from RAND review it and he thought it was just fine. But I’m sure this will carry no weight with you even if I tell you that he is got his PhD in applied math from Harvard under Nobel Prize winner Kenneth Arrow. You’ll just say he was the wrong kind of mathematician.

BA: Well, that’s what I thought you’d say, but it’s disappointing nevertheless. It’s too bad that Richard Kennaway has not weighed in on this as I imagine that you would be more inclined to believe his judgment on this issue. Have you asked him?

Bruce

Incredibly good PCT thinking Eetu,

Both cases (sitting and thinking and sleeping) show that there is no »cannonical« control in inner and outer environment.

In the case of sitting and thinking in the chair (for example) we can make fatal mistake. Observer see that thinker is not controlling anything in the environment. So if he uses »canonical« control (to the extend that Thinker is controlling inside is also controlled outside) he went into »cannonical« trap. Because it is »reversable« relation we can conclude that if nothing is controled outside, also nothing is controlled inside. So »cannonical« conclusion (if we don’t properly use definition of PCT) is that Thinker is an empty »black box« as he is not controlling anything in internal environment to the extend that he is controlling outside.

The problem of this approach is that it is traying to conclude from one case of control (usualy tracking experiment) on all examples of possible behaviors. And most behaviors during a day in real reality does not fit into this model.

So I think that if we try to conclude from special cases in »cannonical« way will always lead us to new control theory or at least will not explain other behaviors. My oppinion is that Bill tryed to make general model which could explain all behaviors. And by my oppinion he succeded so I don’t see any obstacle why we shouldn’t use his model. My proposal through these years was diagram in LCS III and definitions in B:CP. Of course this is my interpretation of PCT which could be the bases for conversations on CSGnet.

I think that starting »stone« of wrong »cannonical« approach is Rick with his neverending analyses and wrong generalization on the basis of »tracking experiment«. It seems that this is the only thing he can do perfectly. It’s not wrong. Wrong is that he wanted to change on one case Bills’ general theory and that he tryed to persuade others that he is right with many manipulative means.

»Tracking experiment« can give a very strong ilussion of »cannonical« control in both environments because it is coming to such a precise result. But this is extreme case (0.99). That’s why ilussion is so strong. I think that in normal life situations nothing is »controlled« with such a high correlation so it’s right to talk about controlling in internal environment and affecting outer environment for the purposes of control in inner environment.Â

Instead of manipulating with Bills’ theory it would be better if he would make his own theory RCT as I proposed him many times (it’s in the archives) and he wouldn’t make such a mess and confussion on CSGnet.

All this was probably not necesary for doing it for years. I should probably explain to Rick how control loop really function in simple words. But he didn’t want to talk. He insulted me saying that he rather watch »football« than waste time with talking to me. And this is a mess he made on CSGnet in these years with his »stupidity« as he marked himself. I know that it’s also my fault, but I can’t go out of my skin.

So Rick was manipulating with all kinds of means among other are also »paranormal« conclussions. He probably noticed that »Qne-experimen« theory has holes which I showed him many times. So he started producing increadible constructs which should probably lower the gap between PCT and his »one-expriment« theory which I called RCT (Rick Control Theory).

Here is list of some »Paranormal control« nonsenses that Rick invented in his »RCT journey« through these years.

  1.   People control people all the ime
    
  2.   All events in control loop happen at the same time.
    
  3.   There is not only perception but also some »extrasensory perception«
    
  4.   There is always some »controlled variable« in environment of Living control system
    
  5.   Organisms are generaly protected from disturbances
    
  6.   To the extent that LCS controls inside it also controls outside.
    
  7.   Behavior is itself a controlled variable
    
  8.   There is some »Controlled Perceptual Variable«….
    
  9.   There are some »side effects« of output on »controlled variable« in external environment… So it seems that are some »controlledd effects« of output on CV and some »side« or noncontrolled effects on environment.
    
  10. Rick has some Telepathic ability for reading people mind with TCV

  11. There seems to be some »Third eye« or third »z control unit«, beside x and y (left and right eye), for analyzing objects moving in 3 D space (x,y,z). The case with toy helicopter. It seems that nervous system is functioning with independent control units only in 2-dimensions (x,y).

Ithink that Rick even wanted to change PCT diagram with inserting »controlled variable« into PCT diagram (he started immediatelly after Bill died but I stopped him) as he was affirming that it is ALWAYS CONTROLLED VARIABLE in outer environment of controlling person. That means that »controlled variable« has to be all the time in environment of LCS.

But it was clever move from Powers ladies when they decided that nothing will be changed in PCT. I hope that they will always stay on this view point no matter how hard will be preausre from Rick and his »servants«. There were also couple times tendencies that PCT would be changed into »selfregulation« theory. But Powers ladies decided right not to change it. There was also my contribution to that.

From Ricks’ point of veiw there were so many nonsense written here on CSGnet, that I doubt that ever anybody will take PCT seriously if he will go through archives. And we have to count here Ricks’ books and articles which are mostly based on »Behavior is control«, »controlled variable« in outer environment and so on.

I am warning CSGnet for years to what extend of possible »nonsense« can RCT push PCT, but nobody listened. Martin was the only support and Kent. So I was really shocked when Martin announced that RCT is in the game. But I beleive that was just temporarely. He is too good thinker to fall into Ricks’ RCT net.

I think personally that CSGnet should start operating also as educational forum for PCT. And first I think Powers ladies should hire a physiologist or better neurophysiologist od neuropsychologist like Henry Yin is who could explain the basics of nervous system functioning. I think that is a good way which could in many ways limit the imagination and abstract thinking, mathematical interpretations of living organisms functioning which lead to such an extreme manipulative example as Rick is. CSGnet forum has to be equiped with knowledge so that it could recognize nonsense when it appears.

And of course. One day mystery of diagram on p. 191. (B:CP, 2005) in Bill-Dags version has to be solved if PCT is to be completed.

Best,

Boris

···

From: Eetu Pikkarainen [mailto:eetu.pikkarainen@oulu.fi]
Sent: Thursday, November 02, 2017 8:43 AM
To: csgnet@lists.illinois.edu
Subject: RE: The speed�curvature power law of movements: a reappraisal

[Eetu Pikkarainen 2017-11-02 9:24]

Good point, Boris!

I should have been stricter with my words. I have used to differentiate between external and internal action. The latter (for example thinking or dreaming) is not visible for an external observer and it does not affect any environmental variables outside the organism. Instead, the external action affects things in the external environment and it is especially this case that I have used to use the term “behavior� (i.e. observable action). So I think that if there is a case of external action / behavior (as there is if we are studying the movements of the subject) then the subject is controlling its certain perception(s) by affecting by its output some environmental correlates of those perceptions.

Eetu

Please, regard all my statements as questions,

no matter how they are formulated.

From: Boris Hartman [mailto:boris.hartman@masicom.net]
Sent: Wednesday, November 1, 2017 8:38 PM
To: csgnet@lists.illinois.edu
Subject: RE: The speed�curvature power law of movements: a reappraisal

Dear Eetu

From: Eetu Pikkarainen [mailto:eetu.pikkarainen@oulu.fi]
Sent: Wednesday, November 01, 2017 10:47 AM
To: csgnet@lists.illinois.edu
Subject: RE: The speed�curvature power law of movements: a reappraisal

[Eetu Pikkarainen 2017-11-01]

(at the risk to be ridiculed…)

I should be but as a humanist, I try not to be ashamed because of missing mathematical competence. I practice my understanding by composing a non-mathematical description of what is going on in this case of PCT and Power Law.

When a living being is producing a movement trajectory by moving itself (e.g. crawling) or its organs (e.g. hand in a drawing task) there seems to be a certain dependence between the curvature of the trajectory (proceeding straight or turning to some direction) and the speed/velocity (understood here as a moved distance along the trajectory during a time unit). The normal case is that the speed is stable on the straight line but it slows down in a curve.

Now the first question is why that slowdown in the curve takes place. The second question is why the dependence between curve and speed has those certain values, which have been observed in different situations. That latter question will be postponed.

EP : PCT view is generally that the behavior of an organism is that it controls its certain perception(s)

HB : Sorry Eetu to not agree with you. It’s not that behavior “controls perception� because behavior can’t be controlled. It just affects input generally. If you are sleeping how you are “controlling� perception with behavior ?

EP : ….by affecting by its outtput some environmental correlates of those perceptions.

HB : Output can affect some correlates of perception in environment, but it has nothing to do with control in environment. What correlate you are affecting in environment if you are observing. And what correlate you are affecting in environment if you are sitting and thinking ? You just affect input. That’s what “feedback� is.

Bill P (LCS III):

FEED-BACK FUNCTION : The box represents the set of physical laws, properties, arrangements, linkages, by which the action 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 : You put it very efficiently what is important about PCT in other post :

Eetu earlier : I think that when I am telling about PCT it is generally best to start from the idea of self-preservation, that any organism - from the most simple to most complex - must control its intrinsic variables to stay alive. From that I can continue to interaction with environment, the must of affecting and stabilizing things in the environment. Only after that it is possible to start to compare organism to thermostat and draw technical diagrams. Thus it goes from soft and warm to hard and technical.

HB : It’s control in organism that is on first place and behavior just support to control in organism. That’s what Bills’ definition is talking about.

Bill P (B:CP):

CONTROL : Achievement and maintenance of a preselected state in the controlling system, through actions on the environment that also cancel the effects of disturbances.

HB : So you think right that what is important is preselected state in organism which includes »intrinsic variables«. Internal control is of most importance. What happens in outer environment is important but supporting to internal control. Behavior is »fired« from internal environment not external in accordance how internal environment is controlled. This is the function of internal and external effectors.

Best,

Boris

EP : So when an organism is moving it can be controlling for its distance from some object to be long (if the object is perceived as dangerous) or short (if the object is perceived as desirable). Any regularities of behavior are often assumed to be side effects of control. (Not side effects of observation.)

EP : At the moment I have no idea what the larvae are controlling in those experiments but introspectively I can imagine some possible perceptions I would control in a drawing task. First, I control seeing me a helpful aid in science making and being an obedient test subject and following to the rules. Then I would control to see the pen moving in a calm and nice way on the paper. At the same time, I control that the pen follows the guiding line as strictly as possible. I think that my output function is such that it is easier to follow a line with certain kind of curvature than with another kind. We humans get much practice to draw just certain kind of lines when we learn to draw and write. But there can also be some more general reasons why we use just those curves in our letters and typical drawings that we use. Anyway, it feels much more natural to draw a circle or looped circles than rounded polygons.

Therefore, the increased difficulty in controlling of the latter perception (following the line) would draw some effort away from the control of the first perception (keeping the steady or moderate speed). Or rather the slowing down the speed will make it easier to control the following the line. (A straight line is easier to draw with higher speed than very slowly.) So the slowdown could be a side effect of control. Perhaps something similar is going on with larvae? Is it easier for them to go straight forward? Is it an additional challenge to turn – to decide to turn and not to continue forward? Would the slowdown make it easier to control the perception of the new direction?

Is that at all where the PCT view of Power Law could begin?

Eetu

From: Alex Gomez-Marin [mailto:agomezmarin@gmail.com]
Sent: 31. lokakuuta 2017 18:01
To: Alex Gomez-Marin agomezmarin@gmail.com; csgnet@lists.illinois.edu
Subject: Re: The speed�curvature power law of movements: a reappraisal

regardless of your helicopter data and RCT mantras, it would be good if someone from CSGnet took seriously the challenge to PCT that the speed-curvature power law entails.

any figure panel of our paper proves rick’s mathematical claims wrong: the PL is not a must and when it takes place it is not trivial and can have different exponents.

now, how can “control of perception” explain that phenomenon? claiming it is an illusion because it does not fit in the dogma is like creationists insisting that dino fossils are bogus.

so, as adam and myself take this job seriously, and given how many optimal control and nonPCT theories explain the data, I think Bill would really find his edifice crumbling, or at least unable. so, take your best shot at it and really challenge your “revolutionary paradigm changing” theory of behavior.

On Sun, 29 Oct 2017 at 02:48, Richard Marken rsmarken@gmail.com wrote:

[From Rick Marken (2017.10.28.1745)

On Sat, Oct 28, 2017 at 3:34 PM, Alex Gomez-Marin agomezmarin@gmail.com wrote:

attached

RM: Finally! Thank you, Alex. I hope the journal gives us an opportunity to respond. But for now I have only one word for you: helicopter movements. Oh, that’s two words But you know how bad I am at math;-)

Best

Rick

Richard S. Marken

"Perfection is achieved not when you have nothing more to add, but when you
have nothing left to take away.�
–Antoine de Saint-Exupery

Alex Gomez-Marin
behavior-of-organisms.org

[From Fred Nickols (2017.11.06.0612 ET)]

Rick: While watching a football game yesterday, I speculated that catching a football fit with your catching fly balls work. I wonder if you could do the same for a quarterback throwing them?

Fred Nickols

···

From: Richard Marken [mailto:rsmarken@gmail.com]
Sent: Sunday, November 5, 2017 6:15 PM
To: csgnet@lists.illinois.edu
Subject: Re: The speed�curvature power law of movements: a reappraisal

[From Rick Marken (2017.11.05.1515)]

Bruce Nevin (2017.11.05.1755 ET)

Rick Marken (2017.11.05.1220) –

What we showed is that the curved paths taken by both pursuers and a PCT model of those pursuers (a model that accounts for on average 93% of the variance in the curved paths taken by pursuers on 41 different trials ) exhibits a power law relationship between speed and curvature. This is evidence that the power law is a side-effect of the outputs that produced the curved paths as the means of controlling for intercepting

BN: Does this hold also for the paths taken by people catching baseballs?

RM:Yes, and it also holds for people catching footballs thrown to themselves (based on the data from Shaffer, D. M., Marken, R. S., Dolgov, I. and Maynor, A. B. (2015) Catching objects thrown to oneself: Testing the generality of a control strategy for object interception, *Perception,*44, 400-409).

Best

Rick

Richard S. Marken

"Perfection is achieved not when you have nothing more to add, but when you
have nothing left to take away.�
–Antoine de Saint-Exupery

Down

···

From: Richard Marken [mailto:rsmarken@gmail.com]
Sent: Monday, November 06, 2017 12:15 AM
To: csgnet@lists.illinois.edu
Subject: Re: The speed�curvature power law of movements: a reappraisal

[From Rick Marken (2017.11.05.1515)]

Bruce Nevin (2017.11.05.1755 ET)

Rick Marken (2017.11.05.1220) –

What we showed is that the curved paths taken by both pursuers and a PCT model of those pursuers

HB : HB : Which PCT model of those pursuers ? You call two independent »control units« for »controlling« x,y axis PCT model or how nervous system works ? Stop insulting PCT. It’s your RCT model. You should start calling your work as it should be…

<

(a model that accounts for on average 93% of the variance in the curved paths taken by pursuers on 41 different trials ) exhibits a power law relationship between speed and curvature. This is evidence that the power law is a side-effect of the outputs that produced the curved paths as the means of controlling for intercepting

BN: Does this hold also for the paths taken by people catching baseballs?

RM:Yes, and it also holds for people catching footballs thrown to themselves (based on the data from Shaffer, D. M., Marken, R. S., Dolgov, I. and Maynor, A. B. (2015) Catching objects thrown to oneself: Testing the generality of a control strategy for object interception, *Perception,*44, 400-409).

HB : Good that you didn’t mentioned that this is PCT strategy for object interception. It’s not, wahatever you meant with »football«.

Boris

Best

Rick

Richard S. Marken

"Perfection is achieved not when you have nothing more to add, but when you
have nothing left to take away.�
–Antoine de Saint-Exupery

Down…

···

From: Richard Marken [mailto:rsmarken@gmail.com]
Sent: Monday, November 06, 2017 6:11 PM
To: csgnet@lists.illinois.edu
Subject: Re: The speed�curvature power law of movements: a reappraisal

[From Rick Marken (2017.11.06.0910)]

Bruce Nevin (2017.11.05.19:56 ET)

BN: I’ve been trying unsuccessfully to track this discussion, without being able to focus on it. I may be wildly off base, but this is my take after looking through the two papers this evening.

RM: I think this is a pretty good take on it. Our paper is heavy on the “statistical artifact” and light on the “PCT explanation” for a reason. The original paper had a more detailed discussion of the “PCT explanation” but one of the reviewers didn’t like that part but loved the “statistical artifact” part. So I had to trim the “PCT explanation” considerably. But PCT sneaks in at the beginning of the article in this paragraph:

Although a third variable is a plausible explanation of
the correlation between curvature and velocity, it does not
explain why that correlation is consistently found to follow
a power law, per Eq. 1. A third variable explanation
requires that the cause of movement—the muscle forces—
consissistently affects curvature and velocity in such a way
that velocity is a power function of curvature. However,
this explanation ignores the fact that different muscle forces
are required to produce the same movement trajectory on
different occasions due to variations in the circumstances
that exist each time the movement is produced (Marken
1988). For example, the forces required to move a finger in
an elliptical trajectory are different each time the movement
is produced due to slight changes in one’s orientation relative
to gravity. Therefore, muscle forces will not be consistently
related to the curvature and velocity of the movement;
the same power relationship between curvature and velocity
will be associated with somewhat different muscle forces
each time the same movement trajectory is produced.

RM: This is the PCT explanation of why we though the explanation of the power law might be found in the mathematics of how curvature and velocity are measured; and, as you note, a large part of our paper is dedicated to showing that this is, indeed, the case. But this PCT-based observation alone – that, due to varying disturbances, different muscle forces are being used to produce the same curved movement on different occasions; that variable means must be used to produce consistent results – is enough to lead one to suspect that the power law that is found for the resulting movement can’t possibly be telling us anything about how that movement was produced. That’s why I have been rather surprised (and disappointed) that all these presumed PCT experts here on CSGNet are making out like I’m the great enemy of PCT

HB : What is truue is true…

for pointing out one of the most basic facts about behavior that we get from PCT; consistent results are produced by variable means. It’s called “control” and curved movements (indeed, all movements) are controlled (consistently produced) results of (necessarily variable) muscle forces.

HB : What is true is true…

J

Best

Rick

Rick Marken (2017.11.05.1220) –

What we showed is that the curved paths taken by both pursuers and a PCT model of those pursuers (a model that accounts for on average 93% of the variance in the curved paths taken by pursuers on 41 different trials ) exhibits a power law relationship between speed and curvature. This is evidence that the power law is a side-effect of the outputs that produced the curved paths as the means of controlling for intercepting

Sounds to me like this is the central finding. But it’s not so clear that this is the main point of Marken & Shaffer (2017) (posted by Alex on March 19, Subject: Power Law Publication). What you say there is “The present paper shows that the power law is actually a statistical artifact that results from mistaking a correlational for a causal relationship between variables… a mathematical consequence of the way that these variables are calculated.”

Zago, Matic, Flash, Gomez-Marin, and Lacquaniti (2017), which Alex posted at the start of this thread on 10/28, does not talk about control theory and mentions control systems only once (on p. 12 of the unpagenated reprint: an “experimental finding … implies that the control systems are [cap]able of establishing non-trivial co-regulations of path geometry and kinematics”). I may be mistaken, but it seems to me that the few and sporadic other uses of the word control in the article refer to motor control systems in a conventional way that does not invoke negative-feedback control.

We know that that negative-feedback control systems that use movements to control their input do not calculate the path geometry or kinematics of those movements, though the movements in the cases considered here can be described with path geometry and kinematics. Indeed, that is the final point of the Marken & Shaffer paper. The problem appears to be that the brief mention of this experimental finding at the end of the paper is dwarfed and obscured by the protracted critique that precedes it and which has every appearance of being presented as the main point of the paper.

Zago, Matic, et al. do not refer to the control-system model discussed in the short final sections of the Marken & Shaffer paper (called there a COV model), nor do they acknowledge the assertion that

The movements produced by the COV model accounted for an average of 93% of the variance in the movements of the actual pursuers over all trials … without any attempt to produce trajectories that followed a power law. Nevertheless, the model trajectories, like those of the actual pursuers, followed a power law with an exponent equivalent to that found in other studies of similarly curved movement trajectories… [T]he observed power law is a mathematical “side effect” of the model’s purposeful behavior. Specifically, it is a mathematical property of the trajectories that result from the model acting (varying ox and oy) to achieve its purpose of keeping the controlled perceptual variables…at the specified reference values.

Zago, Matic, et al say that Marken & Shaffer claim “that this power law is simply a statistical artifact, being a mathematical consequence of the way speed and curvature are calculated”. This is almost a direct quote of the passage cited above, here again: “a statistical artifact that results from mistaking a correlational for a causal relationship between variables… a mathematical consequence of the way that these variables are calculated.” Substitute “speed and curvature” for “variables”.

Zago, Matic, et al critique the assertion that “Since neither of these variables is manipulated under controlled conditions, any observed relationship between them cannot be considered to be causal.” However, the final claim at the end of Marken & Shaffer is that the power law is not a consequence of calculating speed and curvature, but rather a consequence of control. Isn’t this the real basis for the argument that correlation is not causation?

It appears to me that the rejoinder by Zago, Matic, et al overlooked the demonstration that is the real point of the paper, and that they did so because the critique of statistical methods of power law analysis takes up the central and largest sections of the Marken & Shaffer paper and seems to be its main argument. It also follows, I think, that however the mathematical quarrel between you and Martin is resolved, it will have no bearing on that substantial point: control systems produce ‘power law’ effects without doing power law calculations.

Thus, Zago, Matic, et al say “D cannot be considered an independent predictor of A (or V), because D itself depends on A (or V),” etc., echoing Martin’s objection to predicting V from V. But however the power law is calculated, it is descriptive, whereas a control model is generative, and errors or misconstruals in that calculation are beside that main point.

They rather acknowledge this in concluding

The issue that remains to be solved concerns the physiological origins of the power law. But this is a different topic to be covered in a forthcoming article.

It is a different topic which was covered in Marken & Shaffer (2017) only in the appendix-like concluding sections. I wonder, will their forthcoming discussion of “the physiological origins of the power law” recognize that control systems behave according to the power law without an elaborate physiological account? Will that future paper refer to the final sections of Marken & Shaffer (2017)?

/Bruce

On Sun, Nov 5, 2017 at 6:15 PM, Richard Marken rsmarken@gmail.com wrote:

[From Rick Marken (2017.11.05.1515)]

Bruce Nevin (2017.11.05.1755 ET)

Rick Marken (2017.11.05.1220) –

What we showed is that the curved paths taken by both pursuers and a PCT model of those pursuers (a model that accounts for on average 93% of the variance in the curved paths taken by pursuers on 41 different trials ) exhibits a power law relationship between speed and curvature. This is evidence that the power law is a side-effect of the outputs that produced the curved paths as the means of controlling for intercepting

BN: Does this hold also for the paths taken by people catching baseballs?

RM:Yes, and it also holds for people catching footballs thrown to themselves (based on the data from Shaffer, D. M., Marken, R. S., Dolgov, I. and Maynor, A. B. (2015) Catching objects thrown to oneself: Testing the generality of a control strategy for object interception, *Perception,*44, 400-409).

Best

Rick

Richard S. Marken

"Perfection is achieved not when you have nothing more to add, but when you
have nothing left to take away.�
–Antoine de Saint-Exupery

Richard S. Marken

"Perfection is achieved not when you have nothing more to add, but when you
have nothing left to take away.�
–Antoine de Saint-Exupery

Down….

···

From: Richard Marken [mailto:rsmarken@gmail.com]
Sent: Monday, November 06, 2017 7:21 PM
To: csgnet@lists.illinois.edu
Subject: Re: The speed�curvature power law of movements: a reappraisal

[From Rick Marken (2017.11.06.1020)]

Fred Nickols (2017.11.06.0612 ET)–

FN: Rick: While watching a football game yesterday, I speculated that catching a football fit with your catching fly balls work.

RM: Yes, receivers are surely controlling the optical variables controlled by the COV model of catching.

HB : You must be joking again Rick. How many times I proved that your analysis of baseball catch is wrong, It’s pure S-R. Receivers or any other players in any game don’t control any velocity or any environmental variable. Anything in environment does not control behavior of people or players. At least in PCT. Maybe in your RCT players control velocity and tha parabolic flight of the ball or whatever you want. But in PCT flight of the ball is not »controlling« behavior of players. Stop insulting PCT. Even Bill in our conversation saw that you are bluffing. Your demo does not contain any real data how receivers and any other player behave in the game. It’s your pure imagination. There is no such thing in PCT as »controlling« environmental variables. If you meant of course external environment.

FN: I wonder if you could do the same for a quarterback throwing them?

RM: I think that’s a whole different ballgame;-)

HB : No difference. Nervous system still operates on the principles of »Control of perception«. You just have to understand PCT not behaviorism or S-R logic.

RM : The same optical variables might be involved but there are surely higher level functions of those variables involved since the quarterback is throwing to a moving target. So the quarterback must control for the future optical location of the ball matching the future optical location of the receiver.

HB : What does it mean optical ? That everything is not happening in the dark ? »Future optical location« ??? Are you talking about prediction or »feed forward« ?

Why don’t you get some real data to make some real demo. You obviously never played any sport in any league and now you are misleading and confussing people here.

RM : This requires prediction of the future states of a perception, which can be modeled as an extrapolation in imagination or control of a higher level present time perception.

HB : Well finally some PCT. Controlling perception, not environmental variables.

RM : But, whatever, passing is a more difficult control phenomenon to model than catching.

HB : In PCT there is no difference. Whether somebody is throwing or catching or whatever he is doing nervous system is working on same principles. »Control of perception«. Not »control« of environmental variables.

Boris

Best

Rick

Fred Nickols

From: Richard Marken [mailto:rsmarken@gmail.com]
Sent: Sunday, November 5, 2017 6:15 PM
To: csgnet@lists.illinois.edu
Subject: Re: The speed�curvature power law of movements: a reappraisal

[From Rick Marken (2017.11.05.1515)]

Bruce Nevin (2017.11.05.1755 ET)

Rick Marken (2017.11.05.1220) –

What we showed is that the curved paths taken by both pursuers and a PCT model of those pursuers (a model that accounts for on average 93% of the variance in the curved paths taken by pursuers on 41 different trials ) exhibits a power law relationship between speed and curvature. This is evidence that the power law is a side-effect of the outputs that produced the curved paths as the means of controlling for intercepting

BN: Does this hold also for the paths taken by people catching baseballs?

RM:Yes, and it also holds for people catching footballs thrown to themselves (based on the data from Shaffer, D. M., Marken, R. S., Dolgov, I. and Maynor, A. B. (2015) Catching objects thrown to oneself: Testing the generality of a control strategy for object interception, *Perception,*44, 400-409).

Best

Rick

Richard S. Marken

"Perfection is achieved not when you have nothing more to add, but when you
have nothing left to take away.�
–Antoine de Saint-Exupery

Richard S. Marken

"Perfection is achieved not when you have nothing more to add, but when you
have nothing left to take away.�
–Antoine de Saint-Exupery