# Anticipatory Postural Control

**URL:** <http://discourse.iapct.org/t/anticipatory-postural-control/1164>\
**Category:** CSG2019\
**Created:** [May 9, 2019, 1:00am UTC](http://discourse.iapct.org/t/anticipatory-postural-control/1164 "2019-05-09T01:00:56Z")\
**Posts on this page:** 20\
**Page:** 2

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**Author:** ![bleach](http://discourse.iapct.org/user_avatar/discourse.iapct.org/bleach/32/51_2.png) [@bleach](http://discourse.iapct.org/u/bleach)\
**Post date:** [May 10, 2019, 6:03pm UTC](http://discourse.iapct.org/t/anticipatory-postural-control/1164/21 "2019-05-10T18:03:55Z")

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> [Martin Taylor 2019.05.10.10.08]
> 
> > ...Indeed, even Martin's example of sequencing involves a model in that the sequence is a model. In a specific subject that model was either constructed or inherited but at some point, maybe eons ago it was constructed. Some form or reorganization was involved in the construction to correct for uncontrolled or poorly controlled error.

"Pre-action tensioning" is a fine label for the sequence step but keep in mind that the whole sequence is based upon anticipating the need to run the sequence to ensure satisfactory control of perception including an expected future perception.

> Well put. The first paragraph more or less offers the basis for what I have been trying to get across, less skilfully, in the RREV-CEV discussion. The RREV is the fact, the CEV is the model.

I think we're getting somewhere.

> The second paragraph follows the Friston "Free Energy" way of thinking, which is -- I claim -- largely embodied in PCT, but which is somewhat misleading in its wording and in the thinking that leads to the labels given to its elements. In that context, every action is based upon anticipating a future need for any part of the hierarchy that has been reorganized. The PCT wording would say that whatever in the hierarchy is used to reduce the difference between the perception and its reference value is an available means to control the perceptual variable.

I've only casually looked at Friston so I'll defer to you on that though what you say sounds reasonable. To your last sentence I would add that should none of the existing tools tried through reorganization work then the reorganizing process will continue and eventually use ever more drastic changes.

> You might say that the need was anticipated by evolution or reorganization if you wanted to be teleological and say that some agent in the past knew that the cat would at some future time want to bat at a moving object. I would prefer to say that the useful part of the hierarchy was in place to be used for "batting" because of the survival and incremental modification of elements that had been useful in the past for that and other purposes.

Agreed.

> It certainly is possible to construct things because of an anticipated future need. Teachers of mathematics to children are trying to do just that. The teacher or whoever prescribed the curriculum presumably is controlling a perception that at some future time most children will be able to control some perceptions better if they have available the tools of mathematics. I would call that a prediction, but even that might be open to argument.

It certainly fits the "past predicts future" idea.

bill

> **···**
>
> On 5/10/19 8:32 AM, Martin Taylor (\<mailto:mmt-csg@mmtaylor.net\>mmt-csg@mmtaylor.net via csgnet Mailing List) wrote:
> 
> > On 2019/05/9 6:02 PM, Bill Leach (\<mailto:wrleach@cableone.net\>wrleach@cableone.net via csgnet Mailing List) wrote:
> 
> > Martin

---

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**Author:** ![wmansell](http://discourse.iapct.org/user_avatar/discourse.iapct.org/wmansell/32/36_2.png) [@wmansell](http://discourse.iapct.org/u/wmansell)\
**Post date:** [May 10, 2019, 6:41pm UTC](http://discourse.iapct.org/t/anticipatory-postural-control/1164/22 "2019-05-10T18:41:31Z")

</div>

> 

> > Hi folks,

> > See what you make of this: [http://www.pctweb.org/FeedforwardinPCT.pdf](http://www.pctweb.org/FeedforwardinPCT.pdf)

> > I need to get a full version published one day!

> > Essentially the rest of psychology continue to use the word ‘prediction’ because it’s the done thing, and can’t let go of the fact that the term doesn’t best describe what they see in their data, theories and mathematical models, which often begin to converge on PCT but ultimately, don’t.

> >

> > The ‘internal model’ in PCT is purely the functions and parameters that extract and control perceptual variables. Rarely should these approximate to any physical variables in the world. For example, simultaneously controlling the lateral angle, and velocity of the image of a flyball on one’s retina seems to be the best way to get to the right place to catch it. This can be computed from the physical parameters when modelling it on a computer but the brain doesn’t need to do any of this - because it’s world is perceptual, and these two neat perceptual variables dynamically update relative x and y coordinates without the brain having to do ANY computation based on the physical variables that the computer uses.

> >

> > Other internal models in psychology don’t do this - they assume that the brain works like a VR machine, trying to rebuild all the physical parameters in its model, to have an simulated physics engine in the head.

> >

> > The other advantage of perceptual control is that you don’t have to perceive the world accurately - in fact perceiving it in a biased way can be more efficient. Max, ccd has found, following Martin, that if in a PCT model you bias the perception of target position by its current velocity so it looks further along its path than it really is, then the model is a more accurate match with human tracking. This looks like anticipation from the outside, but it’s actually controlling for a biased perception that doesn’t currently exist in the world, but will do in a fraction of a second, but the brain doesn’t need to know this.

> >

> > Please reply as I do want to check Rick, Martin, Bill, Heather, etc, agree?

> >

> > Cheers,

> >

> > Warren

> >

> >

> >

> > >

> **···**
>
> On 5/9/19 2:49 PM, Heather  
> Broccard-Bell ( via csgnet Mailing List) wrote:
> 
> hebell@ucsd.edu
> 
> > ```
> > I agree, nobody is actively making a prediction,
> > 
> > ```
> > 
> > but the system is tuned to perform better in the world as it as  
> > previously experienced it (as stated), because mostly this works  
> > out – because often the world is kind of consistent. What  
> > makes a prediction different, and what then does it mean to make  
> > a prediction? Does a prediction have to be a fully-formed set  
> > of anticipated data? I think I am not understanding what makes  
> > “prediction” different from “bias based on past experience”.
> 
> ```
> I suggest that "bias based on past
> 
> ```
> 
> experience" is the basis for all prediction with respect to  
> control system operation. The term prediction also encompasses  
> things like “the world is going to end in 12 years” which I  
> think it is reasonable to assume is not experience based.
> 
> bill
> 
> > ```
> > On Thu, May 9, 2019 at 1:40 PM
> > 
> > ```
> > 
> > Martin Taylor \<csgnet@lists.illinois.edu \>  
> > wrote:
> 
> > > [Martin Taylor 2019.05.09.16.13]
> > > 
> > > ```
> > > On
> > > 
> > > ```
> > > 
> > > 2019/05/9 3:59 PM, Heather Broccard-Bell (hebell@ucsd.edu via csgnet  
> > > Mailing List) wrote:
> 
> > > > ```
> > > > Sorry, that was meant to go to everyone,
> > > > 
> > > > ```
> > > > 
> > > > not just Martin 🙂
> 
> > > > ```
> > > > On Thu, May 9, 2019
> > > > 
> > > > ```
> > > > 
> > > > at 12:58 PM Heather Broccard-Bell \<hebell@ucsd.edu \>  
> > > > wrote:
> 
> > > > > ```
> > > > > All right, so what then is the
> > > > > 
> > > > > ```
> > > > > 
> > > > > difference between operating on a reference signal  
> > > > > from an internal model, and making a prediction?
> 
> > > ```
> > > If you call the intended result of an action (bringing a
> > > 
> > > ```
> > > 
> > > perception toward its reference value) a prediction, I would  
> > > say that’s a strange use of “prediction”. better  
> > > understanding of what is going on. If I decide to go out and  
> > > do go out, have I predicted that I will go out? The Friston  
> > > “Free Energy” people say exactly that, probably for the  
> > > reasons you suggest below. I would call it at best a  
> > > self-fulfilling prediction, one that comes to pass because  
> > > of the actions of the one who predicts and wouldn’t come to  
> > > pass in the absence of those actions.
> > > 
> > > > > ```
> > > > > Does that not amount to the same
> > > > > 
> > > > > ```
> > > > > 
> > > > > thing? After all, the parameters of the internal  
> > > > > model are set through experience (or evolution –  
> > > > > which is some kind of sort of larger  
> > > > > “experience”). So then the system can be biased  
> > > > > in a way that allows it to function better than  
> > > > > ones that aren’t biased that way in a given  
> > > > > environment.
> 
> > > ```
> > > I could be happy with saying that there is a form of
> > > 
> > > ```
> > > 
> > > prediction here, which is a prediction that the Real Reality  
> > > world will continue to act much as it has been acting for a  
> > > reasonably long time. It’s not a prediction that when the  
> > > cat wants to bat at something it will do what is necessary  
> > > to bat at the thing without falling over. But who is  
> > > predicting? Nobody. Both evolution and reorganization work  
> > > with past data, not predicted future data. The “prediction”  
> > > is simply the working of Natural Law, whether we know the  
> > > law or not.
> > > 
> > > ```
> > > Martin
> > > 
> > > On Thu, May 9, 2019 at 12:14 PM Martin Taylor <mmt@mmtaylor.net> wrote:
> > > 
> > > ```
> > > 
> > > > > > ```
> > > > > > [Martin Taylor
> > > > > > 
> > > > > > ```
> > > > > > 
> > > > > > 2019.05.09.14.35]
> > > > > > 
> > > > > > ```
> > > > > > On
> > > > > > 
> > > > > > ```
> > > > > > 
> > > > > > 2019/05/9 1:53 PM, Heather Broccard-Bell  
> > > > > > wrote:
> 
> > > > > > > ```
> > > > > > > I'm still not sure I
> > > > > > > 
> > > > > > > ```
> > > > > > > 
> > > > > > > satisfactorily answered my own original  
> > > > > > > question, though. And also, if we can  
> > > > > > > compensate for a predicted disturbance  
> > > > > > > (even if we can update our compensation  
> > > > > > > when the compensation is perturbed), the  
> > > > > > > original reference signal is presumably  
> > > > > > > coming from some kind of internal model,  
> > > > > > > no? Is this cool? I thought we were  
> > > > > > > anti-internal model (except for super  
> > > > > > > sophisticated human cognition where we do  
> > > > > > > clearly imagine things)? This suggests  
> > > > > > > cats have one, no?
> 
> > > > > > ```
> > > > > > I guess your question is about what the
> > > > > > 
> > > > > > ```
> > > > > > 
> > > > > > pre-stored energy in the cats muscles is for,  
> > > > > > and whether it implies prediction of an  
> > > > > > external disturbance. I don’t think it does.  
> > > > > > Remember that reference values change, and  
> > > > > > that reorganization changes parameters and  
> > > > > > level-to-level interconnection parameters.  
> > > > > > Maybe the first time the cat ever tried to bat  
> > > > > > at something it didn’t hit it properly, and  
> > > > > > maybe it stumbled or fell after the attempt.  
> > > > > > Nothing of that happened before the cat tried  
> > > > > > to compensate for a disturbance from outside,  
> > > > > > so there’s no prediction involved. No  
> > > > > > subsequent unpredicted disturbance is involved  
> > > > > > in your question.
> > > > > > 
> > > > > > ```
> > > > > > Everything else is internally generated as
> > > > > > 
> > > > > > ```
> > > > > > 
> > > > > > changing reference values feed down the levels  
> > > > > > of control all the way to the individual  
> > > > > > muscle tension control loops. The feedback  
> > > > > > effects of the actions generated by the  
> > > > > > control units whose reference levels were  
> > > > > > changed are fairly consistent over many  
> > > > > > attempts at batting at locally moving things  
> > > > > > (as an observer sees it), so reorganization  
> > > > > > has the opportunity to build the proper  
> > > > > > coordinations and sequences of muscle  
> > > > > > tensions.
> > > > > > 
> > > > > > ```
> > > > > > Yes, there's an internal model. It's in the
> > > > > > 
> > > > > > ```
> > > > > > 
> > > > > > reorganized connections and parameter settings  
> > > > > > for the control loops used to do the batting,  
> > > > > > and part of that is pre-tensioning the muscles  
> > > > > > both to perform the bat and to reduce the  
> > > > > > sudden effect of the action until fast normal  
> > > > > > low-level control loops correct any remaining  
> > > > > > perceptual errors. I bet you do the same if  
> > > > > > you pick up a pile of dishes to put them on a  
> > > > > > shelf. If you started out with slack muscles,  
> > > > > > you might fall when you picked them up, and  
> > > > > > when you released them onto the shelf you  
> > > > > > might fall in the other direction if all the  
> > > > > > tension was devoted to holding up the plates,  
> > > > > > rather than to compensate for the change in  
> > > > > > balance, which you have encountered every time  
> > > > > > you picked up or released a weight since you  
> > > > > > were old enough to try.
> > > > > > 
> > > > > > ```
> > > > > > It might be evolution, not primarily
> > > > > > 
> > > > > > ```
> > > > > > 
> > > > > > reorganization in the individual cat, though,  
> > > > > > because cats are notoriously good at keeping  
> > > > > > their attitude with respect to gravity,  
> > > > > > landing with feet toward the ground if falling  
> > > > > > from a height, and performing remarkable rapid  
> > > > > > body contortions while remaining stable.
> > > > > > 
> > > > > > ```
> > > > > > Martin
> > > > > > 
> > > > > > ```
> > > > > > 
> > > > > > >
> 
> > > > > > > ```
> > > > > > > On
> > > > > > > 
> > > > > > > ```
> > > > > > > 
> > > > > > > Thu, May 9, 2019, 07:18 Warren  
> > > > > > > Mansell \<[wmansell@gmail.com](mailto:wmansell@gmail.com) \>  
> > > > > > > wrote:
> 
> > > > > > > > ```
> > > > > > > > Hurray, PCT wins!
> > > > > > > > 
> > > > > > > > ```
> > > > > > > > 
> > > > > > > > But do any of the readers of  
> > > > > > > > these papers realise?
> 
> > > > > > > >
> 
> > > > > > > > ```
> > > > > > > > On 9 May 2019, at 14:28, Heather
> > > > > > > > 
> > > > > > > > ```
> > > > > > > > 
> > > > > > > > Broccard-Bell (hebell@ucsd.edu  
> > > > > > > > via csgnet Mailing List) \<csgnet@lists.illinois.edu \>  
> > > > > > > > wrote:
> 
> > > > > > > > >
> 
> > > > > > > > > ```
> > > > > > > > > I
> > > > > > > > > 
> > > > > > > > > ```
> > > > > > > > > 
> > > > > > > > > suspect that the  
> > > > > > > > > attached (Aruin, 2003)  
> > > > > > > > > paper goes some way  
> > > > > > > > > toward reconciling the  
> > > > > > > > > “invariant,  
> > > > > > > > > pre-programmed”  
> > > > > > > > > feedforward  
> > > > > > > > > conceptualization with  
> > > > > > > > > the actual phenomenon:  
> > > > > > > > > namely, it’s not  
> > > > > > > > > really invariant (or,  
> > > > > > > > > well, it’s not  
> > > > > > > > > invariant in that  
> > > > > > > > > there is a  
> > > > > > > > > pre-programmed set of  
> > > > > > > > > muscles activated in a  
> > > > > > > > > pre-programmed way).  
> > > > > > > > > So, I suspect that  
> > > > > > > > > some of the problem in  
> > > > > > > > > the “mainstream” is  
> > > > > > > > > semantic.
> 
> > > > > > > > > ```
> > > > > > > > > Anyway,
> > > > > > > > > 
> > > > > > > > > ```
> > > > > > > > > 
> > > > > > > > > long (~500 ms)  
> > > > > > > > > stimulation of motor  
> > > > > > > > > cortex has already  
> > > > > > > > > demonstrated that  
> > > > > > > > > “motor output” seems  
> > > > > > > > > to be about goals,  
> > > > > > > > > and not specific,  
> > > > > > > > > muscle-by-muscle  
> > > > > > > > > motor programs (see  
> > > > > > > > > Graziano, 2002;  
> > > > > > > > > attached), and  
> > > > > > > > > really the only way  
> > > > > > > > > you could get that  
> > > > > > > > > to work is  
> > > > > > > > > hierarchical control  
> > > > > > > > > with continuous  
> > > > > > > > > feedback…
> 
> > > > > > > > > ```
> > > > > > > > > On
> > > > > > > > > 
> > > > > > > > > ```
> > > > > > > > > 
> > > > > > > > > Wed, May 8, 2019,  
> > > > > > > > > 21:16 Martin Taylor  
> > > > > > > > > \<csgnet@lists.illinois.edu \>  
> > > > > > > > > wrote:
> 
> > > > > > > > > > ```
> > > > > > > > > > [Martin Taylor
> > > > > > > > > > 
> > > > > > > > > > ```
> > > > > > > > > > 
> > > > > > > > > > 2019.05.09.00.09]
> > > > > > > > > > 
> > > > > > > > > > > ```
> > > > > > > > > > > [Rick
> > > > > > > > > > > 
> > > > > > > > > > > ```
> > > > > > > > > > > 
> > > > > > > > > > > Marken  
> > > > > > > > > > > 2019-05-08\_17:57:30]
> 
> > > > > > > > > > >
> 
> > > > > > > > > > > ```
> > > > > > > > > > > RM: Some
> > > > > > > > > > > 
> > > > > > > > > > > ```
> > > > > > > > > > > 
> > > > > > > > > > > time ago  
> > > > > > > > > > > Heather  
> > > > > > > > > > > Broccard-Bell  
> > > > > > > > > > > asked me what  
> > > > > > > > > > > the PCT  
> > > > > > > > > > > explanation  
> > > > > > > > > > > might be of a  
> > > > > > > > > > > behavior that  
> > > > > > > > > > > looks like a  
> > > > > > > > > > > pretty robust  
> > > > > > > > > > > example of  
> > > > > > > > > > > anticipatory  
> > > > > > > > > > > (or  
> > > > > > > > > > > feedforward)  
> > > > > > > > > > > control.  
> > > > > > > > > > > Here’s how  
> > > > > > > > > > > Heather  
> > > > > > > > > > > described it  
> > > > > > > > > > > to me:
> 
> > > > > > > > > > >
> 
> > > > > > > > > > > > ```
> > > > > > > > > > > > HB-B:
> > > > > > > > > > > > 
> > > > > > > > > > > > ```
> > > > > > > > > > > > 
> > > > > > > > > > > > I was reading  
> > > > > > > > > > > > about this  
> > > > > > > > > > > > finding (and  
> > > > > > > > > > > > perhaps you  
> > > > > > > > > > > > are already  
> > > > > > > > > > > > familiar)  
> > > > > > > > > > > > that, if if  
> > > > > > > > > > > > you measure  
> > > > > > > > > > > > muscle  
> > > > > > > > > > > > activation  
> > > > > > > > > > > > during  
> > > > > > > > > > > > behavior, you  
> > > > > > > > > > > > often see  
> > > > > > > > > > > > compensatory  
> > > > > > > > > > > > activation of  
> > > > > > > > > > > > the axial  
> > > > > > > > > > > > musculature  
> > > > > > > > > > > > well before  
> > > > > > > > > > > > you get  
> > > > > > > > > > > > activation in  
> > > > > > > > > > > > the muscles  
> > > > > > > > > > > > that direct  
> > > > > > > > > > > > the part of  
> > > > > > > > > > > > the body that  
> > > > > > > > > > > > does the thing  
> > > > > > > > > > > > you’re focused  
> > > > > > > > > > > > on. For  
> > > > > > > > > > > > example, they  
> > > > > > > > > > > > trained cats  
> > > > > > > > > > > > to bat at a  
> > > > > > > > > > > > target with  
> > > > > > > > > > > > their  
> > > > > > > > > > > > forepaw. \*\* Well  
> > > > > > > > > > > > before the  
> > > > > > > > > > > > limb/forepaw  
> > > > > > > > > > > > muscles are  
> > > > > > > > > > > > active, there  
> > > > > > > > > > > > is activation  
> > > > > > > > > > > > in the trunk  
> > > > > > > > > > > > musculature,  
> > > > > > > > > > > > seemingly  
> > > > > > > > > > > > anticipating  
> > > > > > > > > > > > the requisite  
> > > > > > > > > > > > compensatory  
> > > > > > > > > > > > stabilization  
> > > > > > > > > > > > that will  
> > > > > > > > > > > > become  
> > > > > > > > > > > > necessary when  
> > > > > > > > > > > > the forepaw is  
> > > > > > > > > > > > lifted. \*\* I  
> > > > > > > > > > > > am wondering  
> > > > > > > > > > > > what a PCT  
> > > > > > > > > > > > perspective  
> > > > > > > > > > > > might be on  
> > > > > > > > > > > > that? What is  
> > > > > > > > > > > > the relevant  
> > > > > > > > > > > > controlled  
> > > > > > > > > > > > variable,  
> > > > > > > > > > > > since the  
> > > > > > > > > > > > thing that  
> > > > > > > > > > > > actually  
> > > > > > > > > > > > changes  
> > > > > > > > > > > > sensory input  
> > > > > > > > > > > > that should  
> > > > > > > > > > > > activate  
> > > > > > > > > > > > control  
> > > > > > > > > > > > architecture  
> > > > > > > > > > > > hasn’t yet  
> > > > > > > > > > > > happened? Am  
> > > > > > > > > > > > I missing  
> > > > > > > > > > > > something? It  
> > > > > > > > > > > > appears to be  
> > > > > > > > > > > > a rather  
> > > > > > > > > > > > robust  
> > > > > > > > > > > > finding.[emphasis  
> > > > > > > > > > > > mine–RM]
> 
> > > > > > > > > > > …
> 
> > > > > > > > > > > ```
> > > > > > > > > > > RM:
> > > > > > > > > > > 
> > > > > > > > > > > ```
> > > > > > > > > > > 
> > > > > > > > > > > I am posting  
> > > > > > > > > > > this to you  
> > > > > > > > > > > experts on PCT  
> > > > > > > > > > > (with  
> > > > > > > > > > > Heather’s  
> > > > > > > > > > > permission)  
> > > > > > > > > > > because I  
> > > > > > > > > > > think this is  
> > > > > > > > > > > a very  
> > > > > > > > > > > interesting  
> > > > > > > > > > > discovery that  
> > > > > > > > > > > seems to pose  
> > > > > > > > > > > a challenge to  
> > > > > > > > > > > PCT and I  
> > > > > > > > > > > would like to  
> > > > > > > > > > > see what you  
> > > > > > > > > > > think about  
> > > > > > > > > > > this.
> 
> > > > > > > > > > ```
> > > > > > > > > > Here is section
> > > > > > > > > > 
> > > > > > > > > > ```
> > > > > > > > > > 
> > > > > > > > > > of what I wrote to  
> > > > > > > > > > Heather on this  
> > > > > > > > > > question April 12.
> > > > > > > > > > 
> > > > > > > > > > ```
> > > > > > > > > > --------
> > > > > > > > > > 
> > > > > > > > > > [Here is a] quick
> > > > > > > > > > 
> > > > > > > > > > ```
> > > > > > > > > > 
> > > > > > > > > > and dirty PCT  
> > > > > > > > > > approach. I start  
> > > > > > > > > > with the intention  
> > > > > > > > > > to bat at the  
> > > > > > > > > > target, which  
> > > > > > > > > > would set a  
> > > > > > > > > > reference for a  
> > > > > > > > > > sequence that  
> > > > > > > > > > could crudely be  
> > > > > > > > > > taken as “store  
> > > > > > > > > > energy, set  
> > > > > > > > > > trigger, wait,  
> > > > > > > > > > release energy  
> > > > > > > > > > when required”, or  
> > > > > > > > > > in a more general  
> > > > > > > > > > sense “Prepare,  
> > > > > > > > > > wait, execute”.  
> > > > > > > > > > You call the  
> > > > > > > > > > storage  
> > > > > > > > > > “prestabilizing”,  
> > > > > > > > > > but I think Powers  
> > > > > > > > > > would have called  
> > > > > > > > > > that a “dormitive  
> > > > > > > > > > principle” that  
> > > > > > > > > > just labels what  
> > > > > > > > > > happens without in  
> > > > > > > > > > any way explaining  
> > > > > > > > > > how or why. The  
> > > > > > > > > > “stabilizing” is  
> > > > > > > > > > postural control  
> > > > > > > > > > of the normal  
> > > > > > > > > > kind, the same as  
> > > > > > > > > > would happen if  
> > > > > > > > > > you pushed the  
> > > > > > > > > > cat. If you have  
> > > > > > > > > > seen a video of  
> > > > > > > > > > the “Big Dog”  
> > > > > > > > > > robot, you have  
> > > > > > > > > > seen this kind of  
> > > > > > > > > > stabilization.
> > > > > > > > > > 
> > > > > > > > > > ```
> > > > > > > > > > The magician Harry
> > > > > > > > > > 
> > > > > > > > > > ```
> > > > > > > > > > 
> > > > > > > > > > Houdini died  
> > > > > > > > > > because he hadn’t  
> > > > > > > > > > stored the energy  
> > > > > > > > > > to resist a blow  
> > > > > > > > > > to his abdomen  
> > > > > > > > > > when someone hit  
> > > > > > > > > > him before he was  
> > > > > > > > > > prepared, which he  
> > > > > > > > > > did by tensing  
> > > > > > > > > > (supplying energy  
> > > > > > > > > > to) the stomach  
> > > > > > > > > > muscles. He had  
> > > > > > > > > > offered a general  
> > > > > > > > > > challenge that  
> > > > > > > > > > nobody could hit  
> > > > > > > > > > him there hard  
> > > > > > > > > > enough to hurt  
> > > > > > > > > > him, but the  
> > > > > > > > > > hitter was  
> > > > > > > > > > supposed to do it  
> > > > > > > > > > in a formal kind  
> > > > > > > > > > of way, when he  
> > > > > > > > > > was prepared. When  
> > > > > > > > > > the fatal blow was  
> > > > > > > > > > struck, his  
> > > > > > > > > > muscles had  
> > > > > > > > > > insufficient  
> > > > > > > > > > stored energy to  
> > > > > > > > > > oppose the shock  
> > > > > > > > > > energy in the  
> > > > > > > > > > blow.
> > > > > > > > > > 
> > > > > > > > > > ```
> > > > > > > > > > I think the actual
> > > > > > > > > > 
> > > > > > > > > > ```
> > > > > > > > > > 
> > > > > > > > > > stabilization is  
> > > > > > > > > > simply the use of  
> > > > > > > > > > some of the  
> > > > > > > > > > pre-tensioned  
> > > > > > > > > > stored energy in  
> > > > > > > > > > normal postural  
> > > > > > > > > > control against a  
> > > > > > > > > > force that would  
> > > > > > > > > > be destabilizing,  
> > > > > > > > > > but instead of the  
> > > > > > > > > > control being  
> > > > > > > > > > entirely to oppose  
> > > > > > > > > > a sensed  
> > > > > > > > > > disturbance, it is  
> > > > > > > > > > part of the output  
> > > > > > > > > > side support of  
> > > > > > > > > > the sequence  
> > > > > > > > > > controller. The  
> > > > > > > > > > “bat” is not  
> > > > > > > > > > simply sending  
> > > > > > > > > > reference values  
> > > > > > > > > > to muscles that  
> > > > > > > > > > move the paw  
> > > > > > > > > > relative to the  
> > > > > > > > > > torso, it is  
> > > > > > > > > > sending reference  
> > > > > > > > > > values to all the  
> > > > > > > > > > postural muscles  
> > > > > > > > > > in a temporal  
> > > > > > > > > > pattern that has  
> > > > > > > > > > been reorganized  
> > > > > > > > > > into the control  
> > > > > > > > > > hierarchy in the  
> > > > > > > > > > same way as a  
> > > > > > > > > > trained athlete  
> > > > > > > > > > such as a  
> > > > > > > > > > ballerina  
> > > > > > > > > > coordinates the  
> > > > > > > > > > timings and  
> > > > > > > > > > strengths of her  
> > > > > > > > > > muscle movements  
> > > > > > > > > > so that what an  
> > > > > > > > > > observer calls  
> > > > > > > > > > “the” action  
> > > > > > > > > > doesn’t interfere  
> > > > > > > > > > with her balance.
> > > > > > > > > > 
> > > > > > > > > > ```
> > > > > > > > > > Anyway, those are
> > > > > > > > > > 
> > > > > > > > > > ```
> > > > > > > > > > 
> > > > > > > > > > my first thoughts  
> > > > > > > > > > on the question,  
> > > > > > > > > > before breakfast.
> > > > > > > > > > 
> > > > > > > > > > ```
> > > > > > > > > > -------
> > > > > > > > > > 
> > > > > > > > > > I haven't
> > > > > > > > > > 
> > > > > > > > > > ```
> > > > > > > > > > 
> > > > > > > > > > considered the  
> > > > > > > > > > problem since  
> > > > > > > > > > then, but I  
> > > > > > > > > > thought I might  
> > > > > > > > > > offer the  
> > > > > > > > > > suggestion.
> > > > > > > > > > 
> > > > > > > > > > ```
> > > > > > > > > > The saying
> > > > > > > > > > 
> > > > > > > > > > ```
> > > > > > > > > > 
> > > > > > > > > > “Reculer pour  
> > > > > > > > > > mieux sauter”  
> > > > > > > > > > seems to be about  
> > > > > > > > > > the same  
> > > > > > > > > > phenomenon.
> > > > > > > > > > 
> > > > > > > > > > ```
> > > > > > > > > > Martin
> > > > > > > > > > 
> > > > > > > > > > ```
> 
> > > > > > > > > \<aruin2003.pdf\>
> 
> > > > > > > > > \<graziano2002.pdf\>
> 
> > > > > >
> 
> > > > >
> 
> > > > > –  
> > > > > Heather  
> > > > > C. Broccard-Bell,  
> > > > > Ph.D.
> 
> > > > >
> 
> > > > > Adjunct Assistant Professor
> 
> > > > > ```
> > > > > Department
> > > > > 
> > > > > ```
> > > > > 
> > > > > of  
> > > > > Psychological  
> > > > > Sciences
> 
> > > > > ```
> > > > > University
> > > > > 
> > > > > ```
> > > > > 
> > > > > of San Diego
> 
> > > > >
> 
> > > > > ```
> > > > > Visiting
> > > > > 
> > > > > ```
> > > > > 
> > > > > Scholar
> 
> > > > > ```
> > > > > The
> > > > > 
> > > > > ```
> > > > > 
> > > > > role of noise /  
> > > > > variability in  
> > > > > complex,  
> > > > > adaptive systems
> 
> > > > > ```
> > > > > Nieh
> > > > > 
> > > > > ```
> > > > > 
> > > > > Honey Bee Lab
> 
> > > > > ```
> > > > > Division
> > > > > 
> > > > > ```
> > > > > 
> > > > > of Biological  
> > > > > Sciences;  
> > > > > Section of  
> > > > > Ecology,  
> > > > > Behavior, and  
> > > > > Evolution
> 
> > > > > ```
> > > > > University
> > > > > 
> > > > > ```
> > > > > 
> > > > > of California  
> > > > > San Diego
> 
> > > > > ```
> > > > > 619.757.4694
> > > > > 
> > > > > ```
> 
> > > >
> 
> > > > –  
> > > > Heather  
> > > > C. Broccard-Bell,  
> > > > Ph.D.
> 
> > > >
> 
> > > > ```
> > > > Adjunct
> > > > 
> > > > ```
> > > > 
> > > > Assistant  
> > > > Professor
> 
> > > > ```
> > > > Department
> > > > 
> > > > ```
> > > > 
> > > > of Psychological  
> > > > Sciences
> 
> > > > ```
> > > > University
> > > > 
> > > > ```
> > > > 
> > > > of San Diego
> 
> > > >
> 
> > > > ```
> > > > Visiting
> > > > 
> > > > ```
> > > > 
> > > > Scholar
> 
> > > > ```
> > > > The
> > > > 
> > > > ```
> > > > 
> > > > role of noise /  
> > > > variability in  
> > > > complex, adaptive  
> > > > systems
> 
> > > > ```
> > > > Nieh
> > > > 
> > > > ```
> > > > 
> > > > Honey Bee Lab
> 
> > > > ```
> > > > Division
> > > > 
> > > > ```
> > > > 
> > > > of Biological  
> > > > Sciences; Section of  
> > > > Ecology, Behavior,  
> > > > and Evolution
> 
> > > > ```
> > > > University
> > > > 
> > > > ```
> > > > 
> > > > of California San  
> > > > Diego
> 
> > > > ```
> > > > 619.757.4694
> > > > 
> > > > ```
> 
> > >
> 
> > 
> 
> > –  
> > Heather C.  
> > Broccard-Bell, Ph.D.
> 
> > 
> 
> > ```
> > Adjunct
> > 
> > ```
> > 
> > Assistant Professor
> 
> > ```
> > Department
> > 
> > ```
> > 
> > of Psychological Sciences
> 
> > ```
> > University
> > 
> > ```
> > 
> > of San Diego
> 
> > 
> 
> > ```
> > Visiting
> > 
> > ```
> > 
> > Scholar
> 
> > ```
> > The role of
> > 
> > ```
> > 
> > noise / variability in  
> > complex, adaptive systems
> 
> > ```
> > Nieh Honey Bee
> > 
> > ```
> > 
> > Lab
> 
> > ```
> > Division of
> > 
> > ```
> > 
> > Biological Sciences; Section  
> > of Ecology, Behavior, and  
> > Evolution
> 
> > ```
> > University of
> > 
> > ```
> > 
> > California San Diego
> 
> > ```
> > 619.757.4694
> > 
> > ```

---

<div class="post-metadata">

**Author:** ![rsmarken](http://discourse.iapct.org/user_avatar/discourse.iapct.org/rsmarken/32/3553_2.png) [@rsmarken](http://discourse.iapct.org/u/rsmarken)\
**Post date:** [May 10, 2019, 6:59pm UTC](http://discourse.iapct.org/t/anticipatory-postural-control/1164/23 "2019-05-10T18:59:19Z")

</div>

[Rick Marken 2019-05-10\_11:53:31]

RM: Well, this has certainly been an interesting thread so far. I’m happy to see that there is a kind of consensus that the PCT explanation of apparent “anticipatory” behavior is that it is likely to be actions aimed at controlling a “higher level” controlled variable. The landslide was started by Henry Yin who said:

> HY: There’s no conflict between negative feedback and anticipatory behavior. The real question is what kind of CV do you need to produce such behavior.

RM: I think this is the right question: what kind of CV would an organism be controlling that would result in your seeing such apparently "anticipatory"Â behavior. Martin suggests that the CV is a sequence:

> MT: [Here is a] quick and dirty PCT approach. I start with the intention to bat at the target, which would set a reference for a sequence that could crudely be taken as “store energy, set trigger, wait, release energy when required”, or in a more general sense “Prepare, wait, execute”.

RM: And Erling agrees:

> EJ: Â I rather like Martin’s proposal for controlling a prior stage in a sequence. Â

RM: And I agree that the CV is something like a sequence, but not like the one Martin suggests. In the case of the an anticipatory postural adjustments (APAs) seen in the cat’s reaching behavior (described in the Sheppen and Drew paper), it seems to me that the controlled variable is the “reach” itself – an event – like a “golf swing”. An event differs from a sequence only inasmuch as it is a continuously changing sequence of lower level perceptions that is defined over time. The “reach” requires making postural changes over time that get the paw to the intended destination while maintaining balance. So I see the APAs as the initial components of this “reach” event.Â

RM: I see these APA’s as being analogous to the initial muscular movements – for example, contraction of the diaphragm - that are involved in producing a word. These movements are not outputs produced in anticipation of a future disturbance but are the outputs in a control loop that is aimed at controlling a perception of the word. The word itself, like reach, is the controlled variable – a variable that is defined over time.Â

RM: Because “reach” is defined over time it looks like the initial postural adjustments that are made to control this perception are anticipatory. But I believe that they are actually just like the outputs in any control loop – continuously acting to keep the controlled variable in a reference state, protected from disturbances. If this is the case – if APAs are actually the initial outputs of a control loop controlling a variable that is defied over time – then disturbances to these APA’s will be resisted. Heather mentions some data that is consistent with this view:

> NB-B: I suspect that the attached (Aruin, 2003) paper goes some way toward reconciling the “invariant, pre-programmed” feedforward conceptualization with the actual phenomenon: namely, it’s not really invariant (or, well, it’s not invariant in that there is a pre-programmed set of muscles activated in a pre-programmed way). Â

RM: I haven’t read the whole article carefully but apparently what Arium did was look to see whether variations in the initial the position of the body affected the nature of the APAs. And indeed it did. I see these variations in the initial position of the body as disturbances to a controlled variable (in Arium’s case it was “bilateral arm movement” rather than “reach”) and these disturbances are compensated for by the variations in the APAs.Â

RM: Of course, the idea that APAs are the outputs in a control loop controlling a variable defined over time has to be subjected to far more tests. And control models should be built to show that control of a higher level perception, like “reach”, can lead to behavior that “looks” anticipatory. So there’s some general ideas for PCT research that would be a great place to start for researchers interested in doing research on purpose!

BestÂ

Rick

Â

> **···**
>
> –  
> Richard S. MarkenÂ
> 
> "Perfection is achieved not when you have nothing more to add, but when you  
> have nothing left to take away.�  
> Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â --Antoine de Saint-Exupery

---

<div class="post-metadata">

**Author:** ![bleach](http://discourse.iapct.org/user_avatar/discourse.iapct.org/bleach/32/51_2.png) [@bleach](http://discourse.iapct.org/u/bleach)\
**Post date:** [May 10, 2019, 7:08pm UTC](http://discourse.iapct.org/t/anticipatory-postural-control/1164/24 "2019-05-10T19:08:32Z")

</div>

I think the problem here is with the  
inferred meanings for “anticipate,” “predict,” “feedforward,”  
etc. Even Martin used the word “anticipating” in his post where  
he pointing out the idea that the act of changing from a 4 paw  
contact stance to a 3 paw contact stance (or indeed any other  
similar change) would likely involve a sequence of steps to be  
performed in a specific order for control of perception to be  
maintained.

```
    And I suspect that all of us are presuming

```

that a reference for a current perception is the ‘trigger’ for  
the sequence. So it is anticipatory only in the sense that due  
to time restraints there is a delay between the ultimate action  
and the setting of the initial reference.

```
    We do know that "prediction,"

```

“anticipation,” and the like do occur in the higher levels of  
the hierarchy (where we plan and do other cognitive acts).  
However, in the present area of discussion the general  
implications of those terms do not apply.

```
    That is the cat does not pre-tension those

```

core muscles in “anticipation” of raising a paw but rather as a  
result of setting a reference to raise a paw that started a  
sequence for carrying out that action.

bill

> **···**
>
> On 5/10/19 11:38 AM, “Erling Jorgensen”  
> ( via csgnet Mailing List) wrote:
> 
> [EJorgensen@riverbendcmhc.org](mailto:EJorgensen@riverbendcmhc.org)
> 
> > [From Erling Jorgensen (2019.05.10 1243 EDT)]
> 
> > > Rick Marken 2019-05-08\_17:57:30
> 
> > > > 2019/05/9 6:02 PM, Bill Leach…
> 
> > _ **Confidentiality:** _\*  
> > This message is intended only for the addressee, and may  
> > contain information that is privileged and confidential  
> > under HIPAA, 42CFR Part 2, and/or other applicable State  
> > and Federal laws. If you are not the addressee, or the  
> > employer or agent responsible for delivering the message  
> > to the addressee, any dissemination, distribution or  
> > copying of this communication is strictly prohibited. \*\* If  
> > you have received this in error, please notify the  
> > sender immediately and delete the material from your  
> > computer. Thank you for your cooperation.\*\*\*
> 
> > _ **Please also note:** _\* Under 42 CFR part 2 you are prohibited from making any  
> > further disclosure of information that identifies an  
> > individual as having or having had a substance use  
> > disorder unless it is expressly permitted by the  
> > written consent of the individual whose information is  
> > being disclosed or as otherwise permitted by 42 CFR  
> > Part 2.\*
> 
> > ```
> > >>>Martin Taylor 2019.05.10.10.08
> > 
> > ```
> 
> > 
> 
> > ```
> > >>BL: "Pre-action tensioning" is a fine label for
> > 
> > ```
> > 
> > the sequence step but keep in mind that the whole sequence is  
> > based upon _anticipating_ the need to run the sequence  
> > to ensure satisfactory control of perception including an  
> > expected future perception.
> 
> > 
> 
> > ```
> > EJ: I believe this is one of the questions at issue. Does
> > 
> > ```
> > 
> > a PCT control system, using negative feedback in present time,  
> > controlling for a sequence perception or some other type of  
> > complicated body configuration, specifically need  
> > “anticipation” to carry out its control?
> 
> > 
> 
> > ```
> > EJ: I also have a concern about the last three words of
> > 
> > ```
> > 
> > the above quote. While technically a PCT goal (i.e.,  
> > reference standard) could be called “an expected future  
> > perception,” I believe that pre-decides the question, by  
> > leaving open the implication that PCT control has to operate  
> > by means of … [fill in the blank]: some call it  
> > “anticipation,” some call it “prediction,” some call if  
> > “feedforward mechanisms.” There are ways for a PCT hierarchy  
> > to handle such processes, but I don’t think we say they are  
> > necessary for PCT control.
> 
> > 
> 
> > > > > MT: You might say that the need was _anticipated_  
> > > > > by evolution or reorganization if you wanted to be  
> > > > > teleological and say that some agent in the past knew that the  
> > > > > cat would at some future time want to bat at a moving object.  
> > > > > I would prefer to say that the useful part of the hierarchy  
> > > > > was in place to be used for “batting” because of the survival  
> > > > > and incremental modification of elements that had been useful  
> > > > > in the past for that and other purposes.
> 
> > 
> 
> > ```
> > EJ: I thought Heather's original raising of anticipation
> > 
> > ```
> > 
> > was in a different context. Here’s the relevant passage,  
> > quoted by:
> 
> > > Rick Marken 2019-05-08\_17:57:30 –
> 
> > > HB-B: … \*\* Well before the limb/forepaw  
> > > muscles are active, there is activation in the trunk  
> > > musculature, seemingly anticipating the requisite  
> > > compensatory stabilization that will become necessary when  
> > > the forepaw is lifted. \*\*
> 
> > 
> 
> > ```
> > EJ: This is the "behavior that looks like a pretty robust
> > 
> > ```
> > 
> > example of anticipatory (or feedforward) control." To my  
> > mind, “anticipating” here is not about the processes of either  
> > evolution or reorganization in constructing the elementary  
> > control systems that may be involved. It seems rather to be  
> > about producing specific values within those control systems  
> > during a specific situation, values that show themselves as  
> > changes of perception, reference, or output.
> 
> > 
> 
> > ```
> > EJ: While I have only skimmed the research papers that
> > 
> > ```
> > 
> > both Rick & Heather attached, the ‘pre-action tensioning’  
> > (as I’ll continue to call the phenomenon) seems at odds with a  
> > prediction of the PCT model. Rick expressed the issue well:
> 
> > 
> 
> > ```
> > >RM: This finding certainly looks like it is
> > 
> > ```
> > 
> > inconsistent with the predictions of PCT since it looks like  
> > the cat is generating an output (activation of the trunk  
> > musculature) open loop in anticipation of a future disturbance  
> > (the change in orientation of the body when the forepaw is  
> > lifted, a change in orientation that would cause the cat to  
> > lose its balance if the trunk were not in the proper  
> > position).
> 
> > 
> 
> > ```
> > EJ: I don't want PCT to prematurely surrender the field,
> > 
> > ```
> > 
> > by saying, yes of course this has to be feedforward. Does  
> > it?? Henry Yin has published some pretty strong arguments  
> > that “posture control” is a robust negative feedback control  
> > process, readily compatible with PCT as it stands. How much  
> > of this phenomenon can the current model of PCT handle?
> 
> > 
> 
> > All the best,
> 
> > Erling
> 
> > 
> 
> > 
> 
> >

---

<div class="post-metadata">

**Author:** ![Heather\_Broccard-Bel](http://discourse.iapct.org/user_avatar/discourse.iapct.org/heather_broccard-bel/32/43_2.png) [@Heather\_Broccard-Bel](http://discourse.iapct.org/u/Heather_Broccard-Bel)\
**Post date:** [May 10, 2019, 7:25pm UTC](http://discourse.iapct.org/t/anticipatory-postural-control/1164/25 "2019-05-10T19:25:01Z")

</div>

Nice paper! I recently had the pleasure of teaching an upper-division neuro course, and I would strongly suggest, if you haven’t already, reading the first 4 chapters on motor systems in the Purves et al Neuroscience textbook (published 2018). A nice overview of what mainstream neuro thinks – and revealing in 1) how much control architecture is used to explain at least a large part of lower and upper motor neuron systems (no part of any division of the “motor” system lacks sensory afferents, so no part is “all motor”), 2) how the field of neuroscience is a collection of largely atheoretical results, which people sometimes try to tie together into coherent theories, but often don’t, and 3) how skeptical the mainstream authors of this mainstream text are about a lot of those theories and findings 🙂 Teaching that course, which went all the way from mathematical descriptions of neural dynamics, to inter and intracellular signaling cascades, molecular basis of plasticity, and then up to systems, was really useful for me, and spurred several questions, of which anticipatory postural control was one.

Anyway, I would argue the kind of definition of model you’ve outlined in your email, not an accurate VR representation, is also what a lot of at least neuro people mean (I can’t speak so much for the coggies or other kinds of psychologists) – after all, the mainstream idea is that what we experience is not the world as it is, but our nervous system’s interpretation of the information from our sensory systems, coloured by the kinds of experiences that equipment has had in the past, including its evolutionary past – which changes the architecture of the machinery (bias). And, of course, we are active participants in creating those perceptions by behavior, which varies sensory input. Nothing like a 3-D simulation, and also no real parameters are directly represented anywhere, nor do they need to be “reconstructed”. Some of the architecture of the nervous system (e.g., structure of visual cortex; somatosensory cortex; lower motor neuron pools in brainstem and spinal cord) mimics spatial arrangements of sensors and effectors, and this is also some kind of a model… but really, just a transformation of relevant parameters and a way to keep control circuitry organized.

That is, that’s what the neurdos think when they think about theory at all. Mostly, I think most basic neuro researchers are tightly focused on tiny chunks of systems, and more or less totally divorced from any kind of wider context.

So, that was a “listen to myself type” kind of longwinded reply, and I’m not sure I answered any questions…

Heather

> **···**
>
> On Fri, May 10, 2019, 00:52 Warren Mansell [csgnet@lists.illinois.edu](mailto:csgnet@lists.illinois.edu) wrote:
> 
> > 
> 
> > 
> 
> > > Hi folks,
> 
> > > See what you make of this: [http://www.pctweb.org/FeedforwardinPCT.pdf](http://www.pctweb.org/FeedforwardinPCT.pdf)
> 
> > > I need to get a full version published one day!
> 
> > > Essentially the rest of psychology continue to use the word ‘prediction’ because it’s the done thing, and can’t let go of the fact that the term doesn’t best describe what they see in their data, theories and mathematical models, which often begin to converge on PCT but ultimately, don’t.
> 
> > >
> 
> > > The ‘internal model’ in PCT is purely the functions and parameters that extract and control perceptual variables. Rarely should these approximate to any physical variables in the world. For example, simultaneously controlling the lateral angle, and velocity of the image of a flyball on one’s retina seems to be the best way to get to the right place to catch it. This can be computed from the physical parameters when modelling it on a computer but the brain doesn’t need to do any of this - because it’s world is perceptual, and these two neat perceptual variables dynamically update relative x and y coordinates without the brain having to do ANY computation based on the physical variables that the computer uses.
> 
> > >
> 
> > > Other internal models in psychology don’t do this - they assume that the brain works like a VR machine, trying to rebuild all the physical parameters in its model, to have an simulated physics engine in the head.
> 
> > >
> 
> > > The other advantage of perceptual control is that you don’t have to perceive the world accurately - in fact perceiving it in a biased way can be more efficient. Max, ccd has found, following Martin, that if in a PCT model you bias the perception of target position by its current velocity so it looks further along its path than it really is, then the model is a more accurate match with human tracking. This looks like anticipation from the outside, but it’s actually controlling for a biased perception that doesn’t currently exist in the world, but will do in a fraction of a second, but the brain doesn’t need to know this.
> 
> > >
> 
> > > Please reply as I do want to check Rick, Martin, Bill, Heather, etc, agree?
> 
> > >
> 
> > > Cheers,
> 
> > >
> 
> > > Warren
> 
> > >
> 
> > >
> 
> > > On 9 May 2019, at 23:39, Bill Leach ([wrleach@cableone.net](mailto:wrleach@cableone.net) via csgnet Mailing List) [csgnet@lists.illinois.edu](mailto:csgnet@lists.illinois.edu) wrote:
> 
> > > >
> 
> > > > ```
> > > > On 5/9/19 2:49 PM, Heather > > > Broccard-Bell (hebell@ucsd.edu via csgnet Mailing List) wrote:
> > > > 
> > > > ```
> 
> > > > > ```
> > > > > I agree, nobody is actively making a prediction,
> > > > > 
> > > > > ```
> > > > > 
> > > > > but the system is tuned to perform better in the world as it as  
> > > > > previously experienced it (as stated), because mostly this works  
> > > > > out – because often the world is kind of consistent. What  
> > > > > makes a prediction different, and what then does it mean to make  
> > > > > a prediction? Does a prediction have to be a fully-formed set  
> > > > > of anticipated data? I think I am not understanding what makes  
> > > > > “prediction” different from “bias based on past experience”.
> 
> > > > ```
> > > > I suggest that "bias based on past
> > > > 
> > > > ```
> > > > 
> > > > experience" is the basis for all prediction with respect to  
> > > > control system operation. The term prediction also encompasses  
> > > > things like “the world is going to end in 12 years” which I  
> > > > think it is reasonable to assume is not experience based.
> 
> > > > bill
> 
> > > > > ```
> > > > > On Thu, May 9, 2019 at 1:40 PM > > > > Martin Taylor <csgnet@lists.illinois.edu > > > > > wrote:
> > > > > 
> > > > > ```
> 
> > > > > > [Martin Taylor 2019.05.09.16.13]
> > > > > > 
> > > > > > ```
> > > > > > On
> > > > > > 
> > > > > > ```
> > > > > > 
> > > > > > 2019/05/9 3:59 PM, Heather Broccard-Bell (hebell@ucsd.edu via csgnet  
> > > > > > Mailing List) wrote:
> 
> > > > > > > ```
> > > > > > > Sorry, that was meant to go to everyone,
> > > > > > > 
> > > > > > > ```
> > > > > > > 
> > > > > > > not just Martin 🙂
> 
> > > > > > > ```
> > > > > > > On Thu, May 9, 2019 > > > > > > at 12:58 PM Heather Broccard-Bell <hebell@ucsd.edu > > > > > > > wrote:
> > > > > > > 
> > > > > > > ```
> 
> > > > > > > > ```
> > > > > > > > All right, so what then is the
> > > > > > > > 
> > > > > > > > ```
> > > > > > > > 
> > > > > > > > difference between operating on a reference signal  
> > > > > > > > from an internal model, and making a prediction?
> 
> > > > > > ```
> > > > > > If you call the intended result of an action (bringing a
> > > > > > 
> > > > > > ```
> > > > > > 
> > > > > > perception toward its reference value) a prediction, I would  
> > > > > > say that’s a strange use of “prediction”. better  
> > > > > > understanding of what is going on. If I decide to go out and  
> > > > > > do go out, have I predicted that I will go out? The Friston  
> > > > > > “Free Energy” people say exactly that, probably for the  
> > > > > > reasons you suggest below. I would call it at best a  
> > > > > > self-fulfilling prediction, one that comes to pass because  
> > > > > > of the actions of the one who predicts and wouldn’t come to  
> > > > > > pass in the absence of those actions.
> > > > > > 
> > > > > > > > ```
> > > > > > > > Does that not amount to the same
> > > > > > > > 
> > > > > > > > ```
> > > > > > > > 
> > > > > > > > thing? After all, the parameters of the internal  
> > > > > > > > model are set through experience (or evolution –  
> > > > > > > > which is some kind of sort of larger  
> > > > > > > > “experience”). So then the system can be biased  
> > > > > > > > in a way that allows it to function better than  
> > > > > > > > ones that aren’t biased that way in a given  
> > > > > > > > environment.
> 
> > > > > > ```
> > > > > > I could be happy with saying that there is a form of
> > > > > > 
> > > > > > ```
> > > > > > 
> > > > > > prediction here, which is a prediction that the Real Reality  
> > > > > > world will continue to act much as it has been acting for a  
> > > > > > reasonably long time. It’s not a prediction that when the  
> > > > > > cat wants to bat at something it will do what is necessary  
> > > > > > to bat at the thing without falling over. But who is  
> > > > > > predicting? Nobody. Both evolution and reorganization work  
> > > > > > with past data, not predicted future data. The “prediction”  
> > > > > > is simply the working of Natural Law, whether we know the  
> > > > > > law or not.
> > > > > > 
> > > > > > ```
> > > > > > Martin
> > > > > > 
> > > > > > On Thu, May 9, 2019 at 12:14 PM Martin Taylor <mmt@mmtaylor.net> wrote:
> > > > > > 
> > > > > > ```
> > > > > > 
> > > > > > > > > ```
> > > > > > > > > [Martin Taylor
> > > > > > > > > 
> > > > > > > > > ```
> > > > > > > > > 
> > > > > > > > > 2019.05.09.14.35]
> > > > > > > > > 
> > > > > > > > > ```
> > > > > > > > > On
> > > > > > > > > 
> > > > > > > > > ```
> > > > > > > > > 
> > > > > > > > > 2019/05/9 1:53 PM, Heather Broccard-Bell  
> > > > > > > > > wrote:
> 
> > > > > > > > > > ```
> > > > > > > > > > I'm still not sure I
> > > > > > > > > > 
> > > > > > > > > > ```
> > > > > > > > > > 
> > > > > > > > > > satisfactorily answered my own original  
> > > > > > > > > > question, though. And also, if we can  
> > > > > > > > > > compensate for a predicted disturbance  
> > > > > > > > > > (even if we can update our compensation  
> > > > > > > > > > when the compensation is perturbed), the  
> > > > > > > > > > original reference signal is presumably  
> > > > > > > > > > coming from some kind of internal model,  
> > > > > > > > > > no? Is this cool? I thought we were  
> > > > > > > > > > anti-internal model (except for super  
> > > > > > > > > > sophisticated human cognition where we do  
> > > > > > > > > > clearly imagine things)? This suggests  
> > > > > > > > > > cats have one, no?
> 
> > > > > > > > > ```
> > > > > > > > > I guess your question is about what the
> > > > > > > > > 
> > > > > > > > > ```
> > > > > > > > > 
> > > > > > > > > pre-stored energy in the cats muscles is for,  
> > > > > > > > > and whether it implies prediction of an  
> > > > > > > > > external disturbance. I don’t think it does.  
> > > > > > > > > Remember that reference values change, and  
> > > > > > > > > that reorganization changes parameters and  
> > > > > > > > > level-to-level interconnection parameters.  
> > > > > > > > > Maybe the first time the cat ever tried to bat  
> > > > > > > > > at something it didn’t hit it properly, and  
> > > > > > > > > maybe it stumbled or fell after the attempt.  
> > > > > > > > > Nothing of that happened before the cat tried  
> > > > > > > > > to compensate for a disturbance from outside,  
> > > > > > > > > so there’s no prediction involved. No  
> > > > > > > > > subsequent unpredicted disturbance is involved  
> > > > > > > > > in your question.
> > > > > > > > > 
> > > > > > > > > ```
> > > > > > > > > Everything else is internally generated as
> > > > > > > > > 
> > > > > > > > > ```
> > > > > > > > > 
> > > > > > > > > changing reference values feed down the levels  
> > > > > > > > > of control all the way to the individual  
> > > > > > > > > muscle tension control loops. The feedback  
> > > > > > > > > effects of the actions generated by the  
> > > > > > > > > control units whose reference levels were  
> > > > > > > > > changed are fairly consistent over many  
> > > > > > > > > attempts at batting at locally moving things  
> > > > > > > > > (as an observer sees it), so reorganization  
> > > > > > > > > has the opportunity to build the proper  
> > > > > > > > > coordinations and sequences of muscle  
> > > > > > > > > tensions.
> > > > > > > > > 
> > > > > > > > > ```
> > > > > > > > > Yes, there's an internal model. It's in the
> > > > > > > > > 
> > > > > > > > > ```
> > > > > > > > > 
> > > > > > > > > reorganized connections and parameter settings  
> > > > > > > > > for the control loops used to do the batting,  
> > > > > > > > > and part of that is pre-tensioning the muscles  
> > > > > > > > > both to perform the bat and to reduce the  
> > > > > > > > > sudden effect of the action until fast normal  
> > > > > > > > > low-level control loops correct any remaining  
> > > > > > > > > perceptual errors. I bet you do the same if  
> > > > > > > > > you pick up a pile of dishes to put them on a  
> > > > > > > > > shelf. If you started out with slack muscles,  
> > > > > > > > > you might fall when you picked them up, and  
> > > > > > > > > when you released them onto the shelf you  
> > > > > > > > > might fall in the other direction if all the  
> > > > > > > > > tension was devoted to holding up the plates,  
> > > > > > > > > rather than to compensate for the change in  
> > > > > > > > > balance, which you have encountered every time  
> > > > > > > > > you picked up or released a weight since you  
> > > > > > > > > were old enough to try.
> > > > > > > > > 
> > > > > > > > > ```
> > > > > > > > > It might be evolution, not primarily
> > > > > > > > > 
> > > > > > > > > ```
> > > > > > > > > 
> > > > > > > > > reorganization in the individual cat, though,  
> > > > > > > > > because cats are notoriously good at keeping  
> > > > > > > > > their attitude with respect to gravity,  
> > > > > > > > > landing with feet toward the ground if falling  
> > > > > > > > > from a height, and performing remarkable rapid  
> > > > > > > > > body contortions while remaining stable.
> > > > > > > > > 
> > > > > > > > > ```
> > > > > > > > > Martin
> > > > > > > > > 
> > > > > > > > > ```
> > > > > > > > > 
> > > > > > > > > >
> 
> > > > > > > > > > ```
> > > > > > > > > > On
> > > > > > > > > > 
> > > > > > > > > > ```
> > > > > > > > > > 
> > > > > > > > > > Thu, May 9, 2019, 07:18 Warren  
> > > > > > > > > > Mansell \<[wmansell@gmail.com](mailto:wmansell@gmail.com) \>  
> > > > > > > > > > wrote:
> 
> > > > > > > > > > > ```
> > > > > > > > > > > Hurray, PCT wins!
> > > > > > > > > > > 
> > > > > > > > > > > ```
> > > > > > > > > > > 
> > > > > > > > > > > But do any of the readers of  
> > > > > > > > > > > these papers realise?
> 
> > > > > > > > > > >
> 
> > > > > > > > > > > ```
> > > > > > > > > > > On 9 May 2019, at 14:28, Heather > > > > > > > > > > Broccard-Bell (hebell@ucsd.edu > > > > > > > > > > via csgnet Mailing List) <csgnet@lists.illinois.edu > > > > > > > > > > > wrote:
> > > > > > > > > > > 
> > > > > > > > > > > ```
> 
> > > > > > > > > > > >
> 
> > > > > > > > > > > > ```
> > > > > > > > > > > > I
> > > > > > > > > > > > 
> > > > > > > > > > > > ```
> > > > > > > > > > > > 
> > > > > > > > > > > > suspect that the  
> > > > > > > > > > > > attached (Aruin, 2003)  
> > > > > > > > > > > > paper goes some way  
> > > > > > > > > > > > toward reconciling the  
> > > > > > > > > > > > “invariant,  
> > > > > > > > > > > > pre-programmed”  
> > > > > > > > > > > > feedforward  
> > > > > > > > > > > > conceptualization with  
> > > > > > > > > > > > the actual phenomenon:  
> > > > > > > > > > > > namely, it’s not  
> > > > > > > > > > > > really invariant (or,  
> > > > > > > > > > > > well, it’s not  
> > > > > > > > > > > > invariant in that  
> > > > > > > > > > > > there is a  
> > > > > > > > > > > > pre-programmed set of  
> > > > > > > > > > > > muscles activated in a  
> > > > > > > > > > > > pre-programmed way).  
> > > > > > > > > > > > So, I suspect that  
> > > > > > > > > > > > some of the problem in  
> > > > > > > > > > > > the “mainstream” is  
> > > > > > > > > > > > semantic.
> 
> > > > > > > > > > > > ```
> > > > > > > > > > > > Anyway,
> > > > > > > > > > > > 
> > > > > > > > > > > > ```
> > > > > > > > > > > > 
> > > > > > > > > > > > long (~500 ms)  
> > > > > > > > > > > > stimulation of motor  
> > > > > > > > > > > > cortex has already  
> > > > > > > > > > > > demonstrated that  
> > > > > > > > > > > > “motor output” seems  
> > > > > > > > > > > > to be about goals,  
> > > > > > > > > > > > and not specific,  
> > > > > > > > > > > > muscle-by-muscle  
> > > > > > > > > > > > motor programs (see  
> > > > > > > > > > > > Graziano, 2002;  
> > > > > > > > > > > > attached), and  
> > > > > > > > > > > > really the only way  
> > > > > > > > > > > > you could get that  
> > > > > > > > > > > > to work is  
> > > > > > > > > > > > hierarchical control  
> > > > > > > > > > > > with continuous  
> > > > > > > > > > > > feedback…
> 
> > > > > > > > > > > > ```
> > > > > > > > > > > > On
> > > > > > > > > > > > 
> > > > > > > > > > > > ```
> > > > > > > > > > > > 
> > > > > > > > > > > > Wed, May 8, 2019,  
> > > > > > > > > > > > 21:16 Martin Taylor  
> > > > > > > > > > > > \<csgnet@lists.illinois.edu \>  
> > > > > > > > > > > > wrote:
> 
> > > > > > > > > > > > > ```
> > > > > > > > > > > > > [Martin Taylor
> > > > > > > > > > > > > 
> > > > > > > > > > > > > ```
> > > > > > > > > > > > > 
> > > > > > > > > > > > > 2019.05.09.00.09]
> > > > > > > > > > > > > 
> > > > > > > > > > > > > > ```
> > > > > > > > > > > > > > [Rick
> > > > > > > > > > > > > > 
> > > > > > > > > > > > > > ```
> > > > > > > > > > > > > > 
> > > > > > > > > > > > > > Marken  
> > > > > > > > > > > > > > 2019-05-08\_17:57:30]
> 
> > > > > > > > > > > > > >
> 
> > > > > > > > > > > > > > ```
> > > > > > > > > > > > > > RM: Some
> > > > > > > > > > > > > > 
> > > > > > > > > > > > > > ```
> > > > > > > > > > > > > > 
> > > > > > > > > > > > > > time ago  
> > > > > > > > > > > > > > Heather  
> > > > > > > > > > > > > > Broccard-Bell  
> > > > > > > > > > > > > > asked me what  
> > > > > > > > > > > > > > the PCT  
> > > > > > > > > > > > > > explanation  
> > > > > > > > > > > > > > might be of a  
> > > > > > > > > > > > > > behavior that  
> > > > > > > > > > > > > > looks like a  
> > > > > > > > > > > > > > pretty robust  
> > > > > > > > > > > > > > example of  
> > > > > > > > > > > > > > anticipatory  
> > > > > > > > > > > > > > (or  
> > > > > > > > > > > > > > feedforward)  
> > > > > > > > > > > > > > control.  
> > > > > > > > > > > > > > Here’s how  
> > > > > > > > > > > > > > Heather  
> > > > > > > > > > > > > > described it  
> > > > > > > > > > > > > > to me:
> 
> > > > > > > > > > > > > >
> 
> > > > > > > > > > > > > > > ```
> > > > > > > > > > > > > > > HB-B:
> > > > > > > > > > > > > > > 
> > > > > > > > > > > > > > > ```
> > > > > > > > > > > > > > > 
> > > > > > > > > > > > > > > I was reading  
> > > > > > > > > > > > > > > about this  
> > > > > > > > > > > > > > > finding (and  
> > > > > > > > > > > > > > > perhaps you  
> > > > > > > > > > > > > > > are already  
> > > > > > > > > > > > > > > familiar)  
> > > > > > > > > > > > > > > that, if if  
> > > > > > > > > > > > > > > you measure  
> > > > > > > > > > > > > > > muscle  
> > > > > > > > > > > > > > > activation  
> > > > > > > > > > > > > > > during  
> > > > > > > > > > > > > > > behavior, you  
> > > > > > > > > > > > > > > often see  
> > > > > > > > > > > > > > > compensatory  
> > > > > > > > > > > > > > > activation of  
> > > > > > > > > > > > > > > the axial  
> > > > > > > > > > > > > > > musculature  
> > > > > > > > > > > > > > > well before  
> > > > > > > > > > > > > > > you get  
> > > > > > > > > > > > > > > activation in  
> > > > > > > > > > > > > > > the muscles  
> > > > > > > > > > > > > > > that direct  
> > > > > > > > > > > > > > > the part of  
> > > > > > > > > > > > > > > the body that  
> > > > > > > > > > > > > > > does the thing  
> > > > > > > > > > > > > > > you’re focused  
> > > > > > > > > > > > > > > on. For  
> > > > > > > > > > > > > > > example, they  
> > > > > > > > > > > > > > > trained cats  
> > > > > > > > > > > > > > > to bat at a  
> > > > > > > > > > > > > > > target with  
> > > > > > > > > > > > > > > their  
> > > > > > > > > > > > > > > forepaw. \*\* Well  
> > > > > > > > > > > > > > > before the  
> > > > > > > > > > > > > > > limb/forepaw  
> > > > > > > > > > > > > > > muscles are  
> > > > > > > > > > > > > > > active, there  
> > > > > > > > > > > > > > > is activation  
> > > > > > > > > > > > > > > in the trunk  
> > > > > > > > > > > > > > > musculature,  
> > > > > > > > > > > > > > > seemingly  
> > > > > > > > > > > > > > > anticipating  
> > > > > > > > > > > > > > > the requisite  
> > > > > > > > > > > > > > > compensatory  
> > > > > > > > > > > > > > > stabilization  
> > > > > > > > > > > > > > > that will  
> > > > > > > > > > > > > > > become  
> > > > > > > > > > > > > > > necessary when  
> > > > > > > > > > > > > > > the forepaw is  
> > > > > > > > > > > > > > > lifted. \*\* I  
> > > > > > > > > > > > > > > am wondering  
> > > > > > > > > > > > > > > what a PCT  
> > > > > > > > > > > > > > > perspective  
> > > > > > > > > > > > > > > might be on  
> > > > > > > > > > > > > > > that? What is  
> > > > > > > > > > > > > > > the relevant  
> > > > > > > > > > > > > > > controlled  
> > > > > > > > > > > > > > > variable,  
> > > > > > > > > > > > > > > since the  
> > > > > > > > > > > > > > > thing that  
> > > > > > > > > > > > > > > actually  
> > > > > > > > > > > > > > > changes  
> > > > > > > > > > > > > > > sensory input  
> > > > > > > > > > > > > > > that should  
> > > > > > > > > > > > > > > activate  
> > > > > > > > > > > > > > > control  
> > > > > > > > > > > > > > > architecture  
> > > > > > > > > > > > > > > hasn’t yet  
> > > > > > > > > > > > > > > happened? Am  
> > > > > > > > > > > > > > > I missing  
> > > > > > > > > > > > > > > something? It  
> > > > > > > > > > > > > > > appears to be  
> > > > > > > > > > > > > > > a rather  
> > > > > > > > > > > > > > > robust  
> > > > > > > > > > > > > > > finding.[emphasis  
> > > > > > > > > > > > > > > mine–RM]
> 
> > > > > > > > > > > > > > …
> 
> > > > > > > > > > > > > > ```
> > > > > > > > > > > > > > RM:
> > > > > > > > > > > > > > 
> > > > > > > > > > > > > > ```
> > > > > > > > > > > > > > 
> > > > > > > > > > > > > > I am posting  
> > > > > > > > > > > > > > this to you  
> > > > > > > > > > > > > > experts on PCT  
> > > > > > > > > > > > > > (with  
> > > > > > > > > > > > > > Heather’s  
> > > > > > > > > > > > > > permission)  
> > > > > > > > > > > > > > because I  
> > > > > > > > > > > > > > think this is  
> > > > > > > > > > > > > > a very  
> > > > > > > > > > > > > > interesting  
> > > > > > > > > > > > > > discovery that  
> > > > > > > > > > > > > > seems to pose  
> > > > > > > > > > > > > > a challenge to  
> > > > > > > > > > > > > > PCT and I  
> > > > > > > > > > > > > > would like to  
> > > > > > > > > > > > > > see what you  
> > > > > > > > > > > > > > think about  
> > > > > > > > > > > > > > this.
> 
> > > > > > > > > > > > > ```
> > > > > > > > > > > > > Here is section
> > > > > > > > > > > > > 
> > > > > > > > > > > > > ```
> > > > > > > > > > > > > 
> > > > > > > > > > > > > of what I wrote to  
> > > > > > > > > > > > > Heather on this  
> > > > > > > > > > > > > question April 12.
> > > > > > > > > > > > > 
> > > > > > > > > > > > > ```
> > > > > > > > > > > > > --------
> > > > > > > > > > > > > 
> > > > > > > > > > > > > [Here is a] quick
> > > > > > > > > > > > > 
> > > > > > > > > > > > > ```
> > > > > > > > > > > > > 
> > > > > > > > > > > > > and dirty PCT  
> > > > > > > > > > > > > approach. I start  
> > > > > > > > > > > > > with the intention  
> > > > > > > > > > > > > to bat at the  
> > > > > > > > > > > > > target, which  
> > > > > > > > > > > > > would set a  
> > > > > > > > > > > > > reference for a  
> > > > > > > > > > > > > sequence that  
> > > > > > > > > > > > > could crudely be  
> > > > > > > > > > > > > taken as “store  
> > > > > > > > > > > > > energy, set  
> > > > > > > > > > > > > trigger, wait,  
> > > > > > > > > > > > > release energy  
> > > > > > > > > > > > > when required”, or  
> > > > > > > > > > > > > in a more general  
> > > > > > > > > > > > > sense “Prepare,  
> > > > > > > > > > > > > wait, execute”.  
> > > > > > > > > > > > > You call the  
> > > > > > > > > > > > > storage  
> > > > > > > > > > > > > “prestabilizing”,  
> > > > > > > > > > > > > but I think Powers  
> > > > > > > > > > > > > would have called  
> > > > > > > > > > > > > that a “dormitive  
> > > > > > > > > > > > > principle” that  
> > > > > > > > > > > > > just labels what  
> > > > > > > > > > > > > happens without in  
> > > > > > > > > > > > > any way explaining  
> > > > > > > > > > > > > how or why. The  
> > > > > > > > > > > > > “stabilizing” is  
> > > > > > > > > > > > > postural control  
> > > > > > > > > > > > > of the normal  
> > > > > > > > > > > > > kind, the same as  
> > > > > > > > > > > > > would happen if  
> > > > > > > > > > > > > you pushed the  
> > > > > > > > > > > > > cat. If you have  
> > > > > > > > > > > > > seen a video of  
> > > > > > > > > > > > > the “Big Dog”  
> > > > > > > > > > > > > robot, you have  
> > > > > > > > > > > > > seen this kind of  
> > > > > > > > > > > > > stabilization.
> > > > > > > > > > > > > 
> > > > > > > > > > > > > ```
> > > > > > > > > > > > > The magician Harry
> > > > > > > > > > > > > 
> > > > > > > > > > > > > ```
> > > > > > > > > > > > > 
> > > > > > > > > > > > > Houdini died  
> > > > > > > > > > > > > because he hadn’t  
> > > > > > > > > > > > > stored the energy  
> > > > > > > > > > > > > to resist a blow  
> > > > > > > > > > > > > to his abdomen  
> > > > > > > > > > > > > when someone hit  
> > > > > > > > > > > > > him before he was  
> > > > > > > > > > > > > prepared, which he  
> > > > > > > > > > > > > did by tensing  
> > > > > > > > > > > > > (supplying energy  
> > > > > > > > > > > > > to) the stomach  
> > > > > > > > > > > > > muscles. He had  
> > > > > > > > > > > > > offered a general  
> > > > > > > > > > > > > challenge that  
> > > > > > > > > > > > > nobody could hit  
> > > > > > > > > > > > > him there hard  
> > > > > > > > > > > > > enough to hurt  
> > > > > > > > > > > > > him, but the  
> > > > > > > > > > > > > hitter was  
> > > > > > > > > > > > > supposed to do it  
> > > > > > > > > > > > > in a formal kind  
> > > > > > > > > > > > > of way, when he  
> > > > > > > > > > > > > was prepared. When  
> > > > > > > > > > > > > the fatal blow was  
> > > > > > > > > > > > > struck, his  
> > > > > > > > > > > > > muscles had  
> > > > > > > > > > > > > insufficient  
> > > > > > > > > > > > > stored energy to  
> > > > > > > > > > > > > oppose the shock  
> > > > > > > > > > > > > energy in the  
> > > > > > > > > > > > > blow.
> > > > > > > > > > > > > 
> > > > > > > > > > > > > ```
> > > > > > > > > > > > > I think the actual
> > > > > > > > > > > > > 
> > > > > > > > > > > > > ```
> > > > > > > > > > > > > 
> > > > > > > > > > > > > stabilization is  
> > > > > > > > > > > > > simply the use of  
> > > > > > > > > > > > > some of the  
> > > > > > > > > > > > > pre-tensioned  
> > > > > > > > > > > > > stored energy in  
> > > > > > > > > > > > > normal postural  
> > > > > > > > > > > > > control against a  
> > > > > > > > > > > > > force that would  
> > > > > > > > > > > > > be destabilizing,  
> > > > > > > > > > > > > but instead of the  
> > > > > > > > > > > > > control being  
> > > > > > > > > > > > > entirely to oppose  
> > > > > > > > > > > > > a sensed  
> > > > > > > > > > > > > disturbance, it is  
> > > > > > > > > > > > > part of the output  
> > > > > > > > > > > > > side support of  
> > > > > > > > > > > > > the sequence  
> > > > > > > > > > > > > controller. The  
> > > > > > > > > > > > > “bat” is not  
> > > > > > > > > > > > > simply sending  
> > > > > > > > > > > > > reference values  
> > > > > > > > > > > > > to muscles that  
> > > > > > > > > > > > > move the paw  
> > > > > > > > > > > > > relative to the  
> > > > > > > > > > > > > torso, it is  
> > > > > > > > > > > > > sending reference  
> > > > > > > > > > > > > values to all the  
> > > > > > > > > > > > > postural muscles  
> > > > > > > > > > > > > in a temporal  
> > > > > > > > > > > > > pattern that has  
> > > > > > > > > > > > > been reorganized  
> > > > > > > > > > > > > into the control  
> > > > > > > > > > > > > hierarchy in the  
> > > > > > > > > > > > > same way as a  
> > > > > > > > > > > > > trained athlete  
> > > > > > > > > > > > > such as a  
> > > > > > > > > > > > > ballerina  
> > > > > > > > > > > > > coordinates the  
> > > > > > > > > > > > > timings and  
> > > > > > > > > > > > > strengths of her  
> > > > > > > > > > > > > muscle movements  
> > > > > > > > > > > > > so that what an  
> > > > > > > > > > > > > observer calls  
> > > > > > > > > > > > > “the” action  
> > > > > > > > > > > > > doesn’t interfere  
> > > > > > > > > > > > > with her balance.
> > > > > > > > > > > > > 
> > > > > > > > > > > > > ```
> > > > > > > > > > > > > Anyway, those are
> > > > > > > > > > > > > 
> > > > > > > > > > > > > ```
> > > > > > > > > > > > > 
> > > > > > > > > > > > > my first thoughts  
> > > > > > > > > > > > > on the question,  
> > > > > > > > > > > > > before breakfast.
> > > > > > > > > > > > > 
> > > > > > > > > > > > > ```
> > > > > > > > > > > > > -------
> > > > > > > > > > > > > 
> > > > > > > > > > > > > I haven't
> > > > > > > > > > > > > 
> > > > > > > > > > > > > ```
> > > > > > > > > > > > > 
> > > > > > > > > > > > > considered the  
> > > > > > > > > > > > > problem since  
> > > > > > > > > > > > > then, but I  
> > > > > > > > > > > > > thought I might  
> > > > > > > > > > > > > offer the  
> > > > > > > > > > > > > suggestion.
> > > > > > > > > > > > > 
> > > > > > > > > > > > > ```
> > > > > > > > > > > > > The saying
> > > > > > > > > > > > > 
> > > > > > > > > > > > > ```
> > > > > > > > > > > > > 
> > > > > > > > > > > > > “Reculer pour  
> > > > > > > > > > > > > mieux sauter”  
> > > > > > > > > > > > > seems to be about  
> > > > > > > > > > > > > the same  
> > > > > > > > > > > > > phenomenon.
> > > > > > > > > > > > > 
> > > > > > > > > > > > > ```
> > > > > > > > > > > > > Martin
> > > > > > > > > > > > > 
> > > > > > > > > > > > > ```
> 
> > > > > > > > > > > > \<aruin2003.pdf\>
> 
> > > > > > > > > > > > \<graziano2002.pdf\>
> 
> > > > > > > > >
> 
> > > > > > > >
> 
> > > > > > > > –  
> > > > > > > > Heather  
> > > > > > > > C. Broccard-Bell,  
> > > > > > > > Ph.D.
> 
> > > > > > > >
> 
> > > > > > > > Adjunct Assistant Professor
> 
> > > > > > > > ```
> > > > > > > > Department
> > > > > > > > 
> > > > > > > > ```
> > > > > > > > 
> > > > > > > > of  
> > > > > > > > Psychological  
> > > > > > > > Sciences
> 
> > > > > > > > ```
> > > > > > > > University
> > > > > > > > 
> > > > > > > > ```
> > > > > > > > 
> > > > > > > > of San Diego
> 
> > > > > > > >
> 
> > > > > > > > ```
> > > > > > > > Visiting
> > > > > > > > 
> > > > > > > > ```
> > > > > > > > 
> > > > > > > > Scholar
> 
> > > > > > > > ```
> > > > > > > > The
> > > > > > > > 
> > > > > > > > ```
> > > > > > > > 
> > > > > > > > role of noise /  
> > > > > > > > variability in  
> > > > > > > > complex,  
> > > > > > > > adaptive systems
> 
> > > > > > > > ```
> > > > > > > > Nieh
> > > > > > > > 
> > > > > > > > ```
> > > > > > > > 
> > > > > > > > Honey Bee Lab
> 
> > > > > > > > ```
> > > > > > > > Division
> > > > > > > > 
> > > > > > > > ```
> > > > > > > > 
> > > > > > > > of Biological  
> > > > > > > > Sciences;  
> > > > > > > > Section of  
> > > > > > > > Ecology,  
> > > > > > > > Behavior, and  
> > > > > > > > Evolution
> 
> > > > > > > > ```
> > > > > > > > University
> > > > > > > > 
> > > > > > > > ```
> > > > > > > > 
> > > > > > > > of California  
> > > > > > > > San Diego
> 
> > > > > > > > ```
> > > > > > > > 619.757.4694
> > > > > > > > 
> > > > > > > > ```
> 
> > > > > > >
> 
> > > > > > > –  
> > > > > > > Heather  
> > > > > > > C. Broccard-Bell,  
> > > > > > > Ph.D.
> 
> > > > > > >
> 
> > > > > > > ```
> > > > > > > Adjunct
> > > > > > > 
> > > > > > > ```
> > > > > > > 
> > > > > > > Assistant  
> > > > > > > Professor
> 
> > > > > > > ```
> > > > > > > Department
> > > > > > > 
> > > > > > > ```
> > > > > > > 
> > > > > > > of Psychological  
> > > > > > > Sciences
> 
> > > > > > > ```
> > > > > > > University
> > > > > > > 
> > > > > > > ```
> > > > > > > 
> > > > > > > of San Diego
> 
> > > > > > >
> 
> > > > > > > ```
> > > > > > > Visiting
> > > > > > > 
> > > > > > > ```
> > > > > > > 
> > > > > > > Scholar
> 
> > > > > > > ```
> > > > > > > The
> > > > > > > 
> > > > > > > ```
> > > > > > > 
> > > > > > > role of noise /  
> > > > > > > variability in  
> > > > > > > complex, adaptive  
> > > > > > > systems
> 
> > > > > > > ```
> > > > > > > Nieh
> > > > > > > 
> > > > > > > ```
> > > > > > > 
> > > > > > > Honey Bee Lab
> 
> > > > > > > ```
> > > > > > > Division
> > > > > > > 
> > > > > > > ```
> > > > > > > 
> > > > > > > of Biological  
> > > > > > > Sciences; Section of  
> > > > > > > Ecology, Behavior,  
> > > > > > > and Evolution
> 
> > > > > > > ```
> > > > > > > University
> > > > > > > 
> > > > > > > ```
> > > > > > > 
> > > > > > > of California San  
> > > > > > > Diego
> 
> > > > > > > ```
> > > > > > > 619.757.4694
> > > > > > > 
> > > > > > > ```
> 
> > > > > >
> 
> > > > >
> 
> > > > > –  
> > > > > Heather C.  
> > > > > Broccard-Bell, Ph.D.
> 
> > > > >
> 
> > > > > ```
> > > > > Adjunct
> > > > > 
> > > > > ```
> > > > > 
> > > > > Assistant Professor
> 
> > > > > ```
> > > > > Department
> > > > > 
> > > > > ```
> > > > > 
> > > > > of Psychological Sciences
> 
> > > > > ```
> > > > > University
> > > > > 
> > > > > ```
> > > > > 
> > > > > of San Diego
> 
> > > > >
> 
> > > > > ```
> > > > > Visiting
> > > > > 
> > > > > ```
> > > > > 
> > > > > Scholar
> 
> > > > > ```
> > > > > The role of
> > > > > 
> > > > > ```
> > > > > 
> > > > > noise / variability in  
> > > > > complex, adaptive systems
> 
> > > > > ```
> > > > > Nieh Honey Bee
> > > > > 
> > > > > ```
> > > > > 
> > > > > Lab
> 
> > > > > ```
> > > > > Division of
> > > > > 
> > > > > ```
> > > > > 
> > > > > Biological Sciences; Section  
> > > > > of Ecology, Behavior, and  
> > > > > Evolution
> 
> > > > > ```
> > > > > University of
> > > > > 
> > > > > ```
> > > > > 
> > > > > California San Diego
> 
> > > > > ```
> > > > > 619.757.4694
> > > > > 
> > > > > ```

---

<div class="post-metadata">

**Author:** ![Heather\_Broccard-Bel](http://discourse.iapct.org/user_avatar/discourse.iapct.org/heather_broccard-bel/32/43_2.png) [@Heather\_Broccard-Bel](http://discourse.iapct.org/u/Heather_Broccard-Bel)\
**Post date:** [May 10, 2019, 7:51pm UTC](http://discourse.iapct.org/t/anticipatory-postural-control/1164/26 "2019-05-10T19:51:31Z")

</div>

> I kind of think a lot of the problem is semantic. Some seem to be upset by the term “prediction” or “anticipation”, and I think what Rick/Henry suggest is a reasonable explanation for a _mechanism_ for what most people would call anticipation/prediction. It can’t be magic :))

> We know that both humans and cats fail to show APAs if they are taken by surprise. So yes, some environmental information serves to remove the surprise, kicking the control systems into gear. Is that (those) control system(s), dealing with the appearance of the target often used in the cat experiments to signal the upcoming stimulus, totally divorced from the “paw bat” ones? Should they be coupled? What happens if the expected stimulus never arrives, but the target remains? I guess there is fatigue at some point. What is the relevant question to ask?

> In populations of upper motor neurons in motor and premotor cortex, there is often activity seconds before any movement is observed. What does that mean for control systems? That’s obviously not just delay. Those populations get input from… like everwhere. Motor cortex is bonkers! Â

> 

> 

> 

> > [Rick Marken 2019-05-10\_11:53:31]

> >

> > RM: Well, this has certainly been an interesting thread so far. I’m happy to see that there is a kind of consensus that the PCT explanation of apparent “anticipatory” behavior is that it is likely to be actions aimed at controlling a “higher level” controlled variable. The landslide was started by Henry Yin who said:
> > 
> > > HY: There’s no conflict between negative feedback and anticipatory behavior. The real question is what kind of CV do you need to produce such behavior.
> > 
> > RM: I think this is the right question: what kind of CV would an organism be controlling that would result in your seeing such apparently "anticipatory"Â behavior. Martin suggests that the CV is a sequence:
> > 
> > > MT: [Here is a] quick and dirty PCT approach. I start with the intention to bat at the target, which would set a reference for a sequence that could crudely be taken as “store energy, set trigger, wait, release energy when required”, or in a more general sense “Prepare, wait, execute”.

> > RM: And Erling agrees:
> > 
> > > EJ: Â I rather like Martin’s proposal for controlling a prior stage in a sequence. Â
> > 
> > RM: And I agree that the CV is something like a sequence, but not like the one Martin suggests. In the case of the an anticipatory postural adjustments (APAs) seen in the cat’s reaching behavior (described in the Sheppen and Drew paper), it seems to me that the controlled variable is the “reach” itself – an event – like a “golf swing”. An event differs from a sequence only inasmuch as it is a continuously changing sequence of lower level perceptions that is defined over time. The “reach” requires making postural changes over time that get the paw to the intended destination while maintaining balance. So I see the APAs as the initial components of this “reach” event.Â

> >

> > RM: I see these APA’s as being analogous to the initial muscular movements – for example, contraction of the diaphragm - that are involved in producing a word. These movements are not outputs produced in anticipation of a future disturbance but are the outputs in a control loop that is aimed at controlling a perception of the word. The word itself, like reach, is the controlled variable – a variable that is defined over time.Â

> >

> > RM: Because “reach” is defined over time it looks like the initial postural adjustments that are made to control this perception are anticipatory. But I believe that they are actually just like the outputs in any control loop – continuously acting to keep the controlled variable in a reference state, protected from disturbances. If this is the case – if APAs are actually the initial outputs of a control loop controlling a variable that is defied over time – then disturbances to these APA’s will be resisted. Heather mentions some data that is consistent with this view:
> > 
> > > NB-B: I suspect that the attached (Aruin, 2003) paper goes some way toward reconciling the “invariant, pre-programmed” feedforward conceptualization with the actual phenomenon: namely, it’s not really invariant (or, well, it’s not invariant in that there is a pre-programmed set of muscles activated in a pre-programmed way). Â

> > RM: I haven’t read the whole article carefully but apparently what Arium did was look to see whether variations in the initial the position of the body affected the nature of the APAs. And indeed it did. I see these variations in the initial position of the body as disturbances to a controlled variable (in Arium’s case it was “bilateral arm movement” rather than “reach”) and these disturbances are compensated for by the variations in the APAs.Â

> >

> > RM: Of course, the idea that APAs are the outputs in a control loop controlling a variable defined over time has to be subjected to far more tests. And control models should be built to show that control of a higher level perception, like “reach”, can lead to behavior that “looks” anticipatory. So there’s some general ideas for PCT research that would be a great place to start for researchers interested in doing research on purpose!

> >

> > BestÂ

> >

> > Rick

> > Â

> >

> >

> >

> > –  
> > Richard S. MarkenÂ

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

> **···**
>
> > On Fri, May 10, 2019, 11:59 Richard Marken [csgnet@lists.illinois.edu](mailto:csgnet@lists.illinois.edu) wrote:

---

<div class="post-metadata">

**Author:** ![bleach](http://discourse.iapct.org/user_avatar/discourse.iapct.org/bleach/32/51_2.png) [@bleach](http://discourse.iapct.org/u/bleach)\
**Post date:** [May 10, 2019, 8:14pm UTC](http://discourse.iapct.org/t/anticipatory-postural-control/1164/27 "2019-05-10T20:14:41Z")

</div>

Rick,

> **···**
>
> On 5/10/19 12:59 PM, Richard Marken  
> ( via csgnet Mailing List) wrote:
> 
> [rsmarken@gmail.com](mailto:rsmarken@gmail.com)
> 
> > [Rick Marken 2019-05-10\_11:53:31]
> 
> > 
> 
> > ```
> > RM: Well, this has certainly been an
> > 
> > ```
> > 
> > interesting thread so far. I’m happy to see that there is  
> > a kind of consensus that the PCT explanation of apparent  
> > “anticipatory” behavior is that it is likely to be actions  
> > aimed at controlling a “higher level” controlled variable.  
> > The landslide was started by Henry Yin who said:
> > 
> > ```
> > > HY: There’s no conflict between negative feedback and
> > 
> > ```
> > 
> > anticipatory behavior. The real question is what kind of  
> > CV do you need to produce such behavior.
> > 
> > ```
> > RM: I think this is the right question: what kind of CV
> > 
> > ```
> > 
> > would an organism be controlling that would result in your  
> > seeing such apparently "anticipatory"Â behavior. Martin  
> > suggests that the CV is a sequence:
> > 
> > ```
> > > MT: [Here is a] quick and dirty PCT approach. I start
> > 
> > ```
> > 
> > with the intention to bat at the target, which would set a  
> > reference for a sequence that could crudely be taken as  
> > “store energy, set trigger, wait, release energy when  
> > required”, or in a more general sense “Prepare, wait,  
> > execute”.
> 
> > ```
> > RM: And Erling agrees:
> > 
> > >
> > 
> > > EJ: Â I rather like Martin's proposal for controlling
> > 
> > ```
> > 
> > a prior stage in a sequence. Â
> > 
> > ```
> > RM: And I agree that the CV is something like a sequence,
> > 
> > ```
> > 
> > but not like the one Martin suggests. In the case of the  
> > an anticipatory postural adjustments (APAs) seen in the  
> > cat’s reaching behavior (described in the Sheppen and Drew  
> > paper), it seems to me that the controlled variable is the  
> > “reach” itself – an event – like a “golf swing”. An  
> > event differs from a sequence only inasmuch as it is a  
> > continuously changing sequence of lower level perceptions  
> > that is defined over time. The “reach” requires making  
> > postural changes over time that get the paw to the  
> > intended destination while maintaining balance. So I see  
> > the APAs as the initial components of this “reach” event.
> 
> ```
> I could agree with you here Rick but only
> 
> ```
> 
> if Martin’s intent was to exclude continuous feedback control,  
> which I believe was NOT the case. I admit that his " Prepare, wait, execute" rather reads that way  
> but that is how it would appear to the observer. The simplest  
> form of sequencing would be 2 steps even though in his example  
> he included more steps where it would not be at all unreasonable  
> to infer that waiting and executing were part of that sequence.
> 
> ```
> Pre-tensioning muscles certainly does not
> 
> ```
> 
> have to be driven by anticipation. It could just be wired to be  
> a 2 step process.
> 
> bill
> 
> > 
> 
> > ```
> > RM: I see these APA's as being analogous to
> > 
> > ```
> > 
> > the initial muscular movements – for example, contraction  
> > of the diaphragm - that are involved in producing a word.  
> > These movements are not outputs produced in anticipation  
> > of a future disturbance but are the outputs in a control  
> > loop that is aimed at controlling a perception of the  
> > word. The word itself, like reach, is the controlled  
> > variable – a variable that is defined over time.Â
> 
> > 
> 
> > ```
> > RM: Because "reach" is defined over time it
> > 
> > ```
> > 
> > looks like the initial postural adjustments that are made  
> > to control this perception are anticipatory. But I  
> > believe that they are actually just like the outputs in  
> > any control loop – continuously acting to keep the  
> > controlled variable in a reference state, protected from  
> > disturbances. If this is the case – if APAs are actually  
> > the initial outputs of a control loop controlling a  
> > variable that is defied over time – then disturbances to  
> > these APA’s will be resisted. Heather mentions some data  
> > that is consistent with this view:
> > 
> > ```
> > > NB-B: I suspect that the attached (Aruin, 2003) paper
> > 
> > ```
> > 
> > goes some way toward reconciling the “invariant,  
> > pre-programmed” feedforward conceptualization with the  
> > actual phenomenon: namely, it’s not really invariant (or,  
> > well, it’s not invariant in that there is a pre-programmed  
> > set of muscles activated in a pre-programmed way). Â
> 
> > ```
> > RM: I haven't read the whole article carefully but
> > 
> > ```
> > 
> > apparently what Arium did was look to see whether  
> > variations in the initial the position of the body  
> > affected the nature of the APAs. And indeed it did. I  
> > see these variations in the initial position of the body  
> > as disturbances to a controlled variable (in Arium’s  
> > case it was “bilateral arm movement” rather than  
> > “reach”) and these disturbances are compensated for by  
> > the variations in the APAs.Â
> 
> > 
> 
> > ```
> > RM: Of course, the idea that APAs are the outputs in
> > 
> > ```
> > 
> > a control loop controlling a variable defined over time  
> > has to be subjected to far more tests. And control  
> > models should be built to show that control of a higher  
> > level perception, like “reach”, can lead to behavior  
> > that “looks” anticipatory. So there’s some general  
> > ideas for PCT research that would be a great place to  
> > start for researchers interested in doing research on  
> > purpose!
> 
> > 
> 
> > BestÂ
> 
> > 
> 
> > Rick
> 
> > Â
> 
> > 
> 
> > 
> 
> > 
> 
> > –
> > 
> > ```
> > Richard S.
> > 
> > ```
> > 
> > MarkenÂ
> 
> > ```
> > "Perfection is
> > 
> > ```
> > 
> > achieved not when you have  
> > nothing more to add, but when  
> > you
> > 
> > ```
> > have nothing left to take away.�
> > 
> > Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â 
> > 
> > ```
> > 
> > –Antoine de Saint-Exupery

---

<div class="post-metadata">

**Author:** ![bleach](http://discourse.iapct.org/user_avatar/discourse.iapct.org/bleach/32/51_2.png) [@bleach](http://discourse.iapct.org/u/bleach)\
**Post date:** [May 10, 2019, 9:07pm UTC](http://discourse.iapct.org/t/anticipatory-postural-control/1164/28 "2019-05-10T21:07:07Z")

</div>

Heather, thank you for writing this. Not having been in the  
medical sciences, I don’t have access to much of the literature  
that you guy consume. And even if I did, I neither have the  
background nor the time.

```
  As to time, I'm reminded that some 40+ years ago a dear friend

```

had retired and quipped “That now that he is retired, he does not  
see how he could possibly have had time for work.” I laughed  
heartily over that… until I retired! Now, I understand. I  
can’t say that I understand why but I sure understand why he said  
that!

bill

> **···**
>
> On 5/10/19 1:25 PM, Heather Broccard-Bell wrote:
> 
> > ```
> > Nice paper! I recently had the pleasure of
> > 
> > ```
> > 
> > teaching an upper-division neuro course, and I would strongly  
> > suggest, if you haven’t already, reading the first 4 chapters  
> > on motor systems in the Purves et al Neuroscience textbook  
> > (published 2018). A nice overview of what mainstream neuro  
> > thinks – and revealing in 1) how much control architecture is  
> > used to explain at least a large part of lower and upper motor  
> > neuron systems (no part of any division of the “motor” system  
> > lacks sensory afferents, so no part is “all motor”), 2) how  
> > the field of neuroscience is a collection of largely  
> > atheoretical results, which people sometimes try to tie  
> > together into coherent theories, but often don’t, and 3) how  
> > skeptical the mainstream authors of this mainstream text are  
> > about a lot of those theories and findings 🙂 Teaching that  
> > course, which went all the way from mathematical descriptions  
> > of neural dynamics, to inter and intracellular signaling  
> > cascades, molecular basis of plasticity, and then up to  
> > systems, was really useful for me, and spurred several  
> > questions, of which anticipatory postural control was one.
> 
> > 
> 
> > ```
> > Anyway, I would argue the kind of definition of model
> > 
> > ```
> > 
> > you’ve outlined in your email, not an accurate VR  
> > representation, is also what a lot of at least neuro people  
> > mean (I can’t speak so much for the coggies or other kinds of  
> > psychologists) – after all, the mainstream idea is that what  
> > we experience is not the world as it is, but our nervous  
> > system’s interpretation of the information from our sensory  
> > systems, coloured by the kinds of experiences that equipment  
> > has had in the past, including its evolutionary past – which  
> > changes the architecture of the machinery (bias). And, of  
> > course, we are active participants in creating those  
> > perceptions by behavior, which varies sensory input. Nothing  
> > like a 3-D simulation, and also no real parameters are  
> > directly represented anywhere, nor do they need to be  
> > “reconstructed”. Some of the architecture of the nervous  
> > system (e.g., structure of visual cortex; somatosensory  
> > cortex; lower motor neuron pools in brainstem and spinal cord)  
> > mimics spatial arrangements of sensors and effectors, and this  
> > is also some kind of a model… but really, just a  
> > transformation of relevant parameters and a way to keep  
> > control circuitry organized.
> 
> > 
> 
> > ```
> > That is, that's what the neurdos think when they
> > 
> > ```
> > 
> > think about theory at all. Mostly, I think most basic neuro  
> > researchers are tightly focused on tiny chunks of systems, and  
> > more or less totally divorced from any kind of wider context.
> 
> > 
> 
> > ```
> > So, that was a "listen to myself type" kind of
> > 
> > ```
> > 
> > longwinded reply, and I’m not sure I answered any  
> > questions…
> 
> > 
> 
> > Heather
> > 
> > ```
> > On Fri, May 10, 2019, > 00:52 Warren Mansell <csgnet@lists.illinois.edu > > wrote:
> > 
> > ```
> 
> > >
> 
> > >
> 
> > > > Hi folks,
> 
> > > > See what you make of this: [http://www.pctweb.org/FeedforwardinPCT.pdf](https://urldefense.proofpoint.com/v2/url?u=http-3A__www.pctweb.org_FeedforwardinPCT.pdf&d=DwMDaQ&c=OCIEmEwdEq_aNlsP4fF3gFqSN-E3mlr2t9JcDdfOZag&r=G2rjwc9SjlT6Blyc8su_Md8P_xOsOTRMJ5teQVBC2qU&m=FjzJAQRMBNXP48i_qYOnW6eIqZkHCmMqTI4jrw1CElk&s=C7jcdNRt06CdYZSTXsW7U2Gn1khaVK2K3eu7KCXULQE&e=)
> 
> > > > ```
> > > > I need to get a full version
> > > > 
> > > > ```
> > > > 
> > > > published one day!
> 
> > > > ```
> > > > Essentially the rest of psychology
> > > > 
> > > > ```
> > > > 
> > > > continue to use the word ‘prediction’ because  
> > > > it’s the done thing, and can’t let go of the fact  
> > > > that the term doesn’t best describe what they see  
> > > > in their data, theories and mathematical models,  
> > > > which often begin to converge on PCT but  
> > > > ultimately, don’t.
> 
> > > >
> 
> > > > ```
> > > > The ‘internal model’ in PCT is purely
> > > > 
> > > > ```
> > > > 
> > > > the functions and parameters that extract and  
> > > > control perceptual variables. Rarely should these  
> > > > approximate to any physical variables in the  
> > > > world. For example, simultaneously controlling the  
> > > > lateral angle, and velocity of the image of a  
> > > > flyball on one’s retina seems to be the best way  
> > > > to get to the right place to catch it. This can be  
> > > > computed from the physical parameters when  
> > > > modelling it on a computer but the brain doesn’t  
> > > > need to do any of this - because it’s world is  
> > > > perceptual, and these two neat perceptual  
> > > > variables dynamically update relative x and y  
> > > > coordinates without the brain having to do ANY  
> > > > computation based on the physical variables that  
> > > > the computer uses.
> 
> > > >
> 
> > > > ```
> > > > Other internal models in psychology
> > > > 
> > > > ```
> > > > 
> > > > don’t do this - they assume that the brain works  
> > > > like a VR machine, trying to rebuild all the  
> > > > physical parameters in its model, to have an  
> > > > simulated physics engine in the head.
> 
> > > >
> 
> > > > ```
> > > > The other advantage of perceptual
> > > > 
> > > > ```
> > > > 
> > > > control is that you don’t have to perceive the  
> > > > world accurately - in fact perceiving it in a  
> > > > biased way can be more efficient. Max, ccd has  
> > > > found, following Martin, that if in a PCT model  
> > > > you bias the perception of target position by its  
> > > > current velocity so it looks further along its  
> > > > path than it really is, then the model is a more  
> > > > accurate match with human tracking. This looks  
> > > > like anticipation from the outside, but it’s  
> > > > actually controlling for a biased perception that  
> > > > doesn’t currently exist in the world, but will do  
> > > > in a fraction of a second, but the brain doesn’t  
> > > > need to know this.
> 
> > > >
> 
> > > > ```
> > > > Please reply as I do want to check
> > > > 
> > > > ```
> > > > 
> > > > Rick, Martin, Bill, Heather, etc, agree?
> 
> > > >
> 
> > > > Cheers,
> 
> > > >
> 
> > > > Warren
> 
> > > >
> 
> > > >
> 
> > > > ```
> > > > On 9 May 2019, at 23:39, Bill Leach (wrleach@cableone.net > > > via csgnet Mailing List) <csgnet@lists.illinois.edu > > > > wrote:
> > > > 
> > > > ```
> 
> > > > >
> 
> > > > > ```
> > > > > On
> > > > > 
> > > > > ```
> > > > > 
> > > > > 5/9/19 2:49 PM, Heather Broccard-Bell (hebell@ucsd.edu  
> > > > > via csgnet Mailing List) wrote:
> 
> > > > > > ```
> > > > > > I agree, nobody is actively
> > > > > > 
> > > > > > ```
> > > > > > 
> > > > > > making a prediction, but the system is tuned  
> > > > > > to perform better in the world as it as  
> > > > > > previously experienced it (as stated),  
> > > > > > because mostly this works out – because  
> > > > > > often the world is kind of consistent. What  
> > > > > > makes a prediction different, and what then  
> > > > > > does it mean to make a prediction? Does a  
> > > > > > prediction have to be a fully-formed set of  
> > > > > > anticipated data? I think I am not  
> > > > > > understanding what makes “prediction”  
> > > > > > different from “bias based on past  
> > > > > > experience”.
> 
> > > > > ```
> > > > > I suggest that "bias
> > > > > 
> > > > > ```
> > > > > 
> > > > > based on past experience" is the basis for  
> > > > > all prediction with respect to control  
> > > > > system operation. The term prediction also  
> > > > > encompasses things like “the world is going  
> > > > > to end in 12 years” which I think it is  
> > > > > reasonable to assume is not experience  
> > > > > based.
> 
> > > > > bill
> 
> > > > > > ```
> > > > > > On Thu, > > > > > May 9, 2019 at 1:40 PM Martin Taylor <csgnet@lists.illinois.edu > > > > > > wrote:
> > > > > > 
> > > > > > ```
> 
> > > > > > > ```
> > > > > > > [Martin Taylor
> > > > > > > 
> > > > > > > ```
> > > > > > > 
> > > > > > > 2019.05.09.16.13]
> > > > > > > 
> > > > > > > ```
> > > > > > > On
> > > > > > > 
> > > > > > > ```
> > > > > > > 
> > > > > > > 2019/05/9 3:59 PM, Heather  
> > > > > > > Broccard-Bell (hebell@ucsd.edu  
> > > > > > > via csgnet Mailing List) wrote:
> 
> > > > > > > > ```
> > > > > > > > Sorry, that was meant
> > > > > > > > 
> > > > > > > > ```
> > > > > > > > 
> > > > > > > > to go to everyone, not just Martin  
> > > > > > > > 🙂
> 
> > > > > > > > ```
> > > > > > > > On
> > > > > > > > 
> > > > > > > > ```
> > > > > > > > 
> > > > > > > > Thu, May 9, 2019 at 12:58 PM  
> > > > > > > > Heather Broccard-Bell \<hebell@ucsd.edu \>  
> > > > > > > > wrote:
> 
> > > > > > > > > ```
> > > > > > > > > All right, so
> > > > > > > > > 
> > > > > > > > > ```
> > > > > > > > > 
> > > > > > > > > what then is the difference  
> > > > > > > > > between operating on a  
> > > > > > > > > reference signal from an  
> > > > > > > > > internal model, and making a  
> > > > > > > > > prediction?
> 
> > > > > > > ```
> > > > > > > If you call the intended result of an
> > > > > > > 
> > > > > > > ```
> > > > > > > 
> > > > > > > action (bringing a perception toward its  
> > > > > > > reference value) a prediction, I would  
> > > > > > > say that’s a strange use of  
> > > > > > > “prediction”. better understanding of  
> > > > > > > what is going on. If I decide to go out  
> > > > > > > and do go out, have I predicted that I  
> > > > > > > will go out? The Friston “Free Energy”  
> > > > > > > people say exactly that, probably for  
> > > > > > > the reasons you suggest below. I would  
> > > > > > > call it at best a self-fulfilling  
> > > > > > > prediction, one that comes to pass  
> > > > > > > because of the actions of the one who  
> > > > > > > predicts and wouldn’t come to pass in  
> > > > > > > the absence of those actions.
> > > > > > > 
> > > > > > > > > ```
> > > > > > > > > Does that not
> > > > > > > > > 
> > > > > > > > > ```
> > > > > > > > > 
> > > > > > > > > amount to the same thing?  
> > > > > > > > > After all, the parameters of  
> > > > > > > > > the internal model are set  
> > > > > > > > > through experience (or  
> > > > > > > > > evolution – which is some  
> > > > > > > > > kind of sort of larger  
> > > > > > > > > “experience”). So then the  
> > > > > > > > > system can be biased in a way  
> > > > > > > > > that allows it to function  
> > > > > > > > > better than ones that aren’t  
> > > > > > > > > biased that way in a given  
> > > > > > > > > environment.
> 
> > > > > > > ```
> > > > > > > I could be happy with saying that there
> > > > > > > 
> > > > > > > ```
> > > > > > > 
> > > > > > > is a form of prediction here, which is a  
> > > > > > > prediction that the Real Reality world  
> > > > > > > will continue to act much as it has been  
> > > > > > > acting for a reasonably long time. It’s  
> > > > > > > not a prediction that when the cat wants  
> > > > > > > to bat at something it will do what is  
> > > > > > > necessary to bat at the thing without  
> > > > > > > falling over. But who is predicting?  
> > > > > > > Nobody. Both evolution and  
> > > > > > > reorganization work with past data, not  
> > > > > > > predicted future data. The “prediction”  
> > > > > > > is simply the working of Natural Law,  
> > > > > > > whether we know the law or not.
> > > > > > > 
> > > > > > > ```
> > > > > > > Martin
> > > > > > > 
> > > > > > > On Thu, May 9, 2019 at 12:14 PM Martin > > > > > > Taylor <mmt@mmtaylor.net > > > > > > > wrote:
> > > > > > > 
> > > > > > > ```
> > > > > > > 
> > > > > > > > > > ```
> > > > > > > > > > [Martin Taylor
> > > > > > > > > > 
> > > > > > > > > > ```
> > > > > > > > > > 
> > > > > > > > > > 2019.05.09.14.35]
> > > > > > > > > > 
> > > > > > > > > > ```
> > > > > > > > > > On
> > > > > > > > > > 
> > > > > > > > > > ```
> > > > > > > > > > 
> > > > > > > > > > 2019/05/9 1:53 PM,  
> > > > > > > > > > Heather Broccard-Bell  
> > > > > > > > > > wrote:
> 
> > > > > > > > > > > ```
> > > > > > > > > > > I'm
> > > > > > > > > > > 
> > > > > > > > > > > ```
> > > > > > > > > > > 
> > > > > > > > > > > still not sure I  
> > > > > > > > > > > satisfactorily  
> > > > > > > > > > > answered my own  
> > > > > > > > > > > original question,  
> > > > > > > > > > > though. And also, if  
> > > > > > > > > > > we can compensate for  
> > > > > > > > > > > a predicted  
> > > > > > > > > > > disturbance (even if  
> > > > > > > > > > > we can update our  
> > > > > > > > > > > compensation when the  
> > > > > > > > > > > compensation is  
> > > > > > > > > > > perturbed), the  
> > > > > > > > > > > original reference  
> > > > > > > > > > > signal is presumably  
> > > > > > > > > > > coming from some kind  
> > > > > > > > > > > of internal model,  
> > > > > > > > > > > no? Is this cool? I  
> > > > > > > > > > > thought we were  
> > > > > > > > > > > anti-internal model  
> > > > > > > > > > > (except for super  
> > > > > > > > > > > sophisticated human  
> > > > > > > > > > > cognition where we do  
> > > > > > > > > > > clearly imagine  
> > > > > > > > > > > things)? This  
> > > > > > > > > > > suggests cats have  
> > > > > > > > > > > one, no?
> 
> > > > > > > > > > ```
> > > > > > > > > > I guess your question is
> > > > > > > > > > 
> > > > > > > > > > ```
> > > > > > > > > > 
> > > > > > > > > > about what the pre-stored  
> > > > > > > > > > energy in the cats muscles  
> > > > > > > > > > is for, and whether it  
> > > > > > > > > > implies prediction of an  
> > > > > > > > > > external disturbance. I  
> > > > > > > > > > don’t think it does.  
> > > > > > > > > > Remember that reference  
> > > > > > > > > > values change, and that  
> > > > > > > > > > reorganization changes  
> > > > > > > > > > parameters and  
> > > > > > > > > > level-to-level  
> > > > > > > > > > interconnection  
> > > > > > > > > > parameters. Maybe the  
> > > > > > > > > > first time the cat ever  
> > > > > > > > > > tried to bat at something  
> > > > > > > > > > it didn’t hit it properly,  
> > > > > > > > > > and maybe it stumbled or  
> > > > > > > > > > fell after the attempt.  
> > > > > > > > > > Nothing of that happened  
> > > > > > > > > > before the cat tried to  
> > > > > > > > > > compensate for a  
> > > > > > > > > > disturbance from outside,  
> > > > > > > > > > so there’s no prediction  
> > > > > > > > > > involved. No subsequent  
> > > > > > > > > > unpredicted disturbance is  
> > > > > > > > > > involved in your question.
> > > > > > > > > > 
> > > > > > > > > > ```
> > > > > > > > > > Everything else is
> > > > > > > > > > 
> > > > > > > > > > ```
> > > > > > > > > > 
> > > > > > > > > > internally generated as  
> > > > > > > > > > changing reference values  
> > > > > > > > > > feed down the levels of  
> > > > > > > > > > control all the way to the  
> > > > > > > > > > individual muscle tension  
> > > > > > > > > > control loops. The  
> > > > > > > > > > feedback effects of the  
> > > > > > > > > > actions generated by the  
> > > > > > > > > > control units whose  
> > > > > > > > > > reference levels were  
> > > > > > > > > > changed are fairly  
> > > > > > > > > > consistent over many  
> > > > > > > > > > attempts at batting at  
> > > > > > > > > > locally moving things (as  
> > > > > > > > > > an observer sees it), so  
> > > > > > > > > > reorganization has the  
> > > > > > > > > > opportunity to build the  
> > > > > > > > > > proper coordinations and  
> > > > > > > > > > sequences of muscle  
> > > > > > > > > > tensions.
> > > > > > > > > > 
> > > > > > > > > > ```
> > > > > > > > > > Yes, there's an internal
> > > > > > > > > > 
> > > > > > > > > > ```
> > > > > > > > > > 
> > > > > > > > > > model. It’s in the  
> > > > > > > > > > reorganized connections  
> > > > > > > > > > and parameter settings for  
> > > > > > > > > > the control loops used to  
> > > > > > > > > > do the batting, and part  
> > > > > > > > > > of that is pre-tensioning  
> > > > > > > > > > the muscles both to  
> > > > > > > > > > perform the bat and to  
> > > > > > > > > > reduce the sudden effect  
> > > > > > > > > > of the action until fast  
> > > > > > > > > > normal low-level control  
> > > > > > > > > > loops correct any  
> > > > > > > > > > remaining perceptual  
> > > > > > > > > > errors. I bet you do the  
> > > > > > > > > > same if you pick up a pile  
> > > > > > > > > > of dishes to put them on a  
> > > > > > > > > > shelf. If you started out  
> > > > > > > > > > with slack muscles, you  
> > > > > > > > > > might fall when you picked  
> > > > > > > > > > them up, and when you  
> > > > > > > > > > released them onto the  
> > > > > > > > > > shelf you might fall in  
> > > > > > > > > > the other direction if all  
> > > > > > > > > > the tension was devoted to  
> > > > > > > > > > holding up the plates,  
> > > > > > > > > > rather than to compensate  
> > > > > > > > > > for the change in balance,  
> > > > > > > > > > which you have encountered  
> > > > > > > > > > every time you picked up  
> > > > > > > > > > or released a weight since  
> > > > > > > > > > you were old enough to  
> > > > > > > > > > try.
> > > > > > > > > > 
> > > > > > > > > > ```
> > > > > > > > > > It might be evolution, not
> > > > > > > > > > 
> > > > > > > > > > ```
> > > > > > > > > > 
> > > > > > > > > > primarily reorganization  
> > > > > > > > > > in the individual cat,  
> > > > > > > > > > though, because cats are  
> > > > > > > > > > notoriously good at  
> > > > > > > > > > keeping their attitude  
> > > > > > > > > > with respect to gravity,  
> > > > > > > > > > landing with feet toward  
> > > > > > > > > > the ground if falling from  
> > > > > > > > > > a height, and performing  
> > > > > > > > > > remarkable rapid body  
> > > > > > > > > > contortions while  
> > > > > > > > > > remaining stable.
> > > > > > > > > > 
> > > > > > > > > > ```
> > > > > > > > > > Martin
> > > > > > > > > > 
> > > > > > > > > > ```
> > > > > > > > > > 
> > > > > > > > > > >
> 
> > > > > > > > > > > ```
> > > > > > > > > > > On
> > > > > > > > > > > 
> > > > > > > > > > > ```
> > > > > > > > > > > 
> > > > > > > > > > > Thu, May 9,  
> > > > > > > > > > > 2019, 07:18  
> > > > > > > > > > > Warren Mansell  
> > > > > > > > > > > \<[wmansell@gmail.com](mailto:wmansell@gmail.com) \>  
> > > > > > > > > > > wrote:
> 
> > > > > > > > > > > > ```
> > > > > > > > > > > > Hurray,
> > > > > > > > > > > > 
> > > > > > > > > > > > ```
> > > > > > > > > > > > 
> > > > > > > > > > > > PCT wins! But  
> > > > > > > > > > > > do any of the  
> > > > > > > > > > > > readers of  
> > > > > > > > > > > > these papers  
> > > > > > > > > > > > realise?
> 
> > > > > > > > > > > >
> 
> > > > > > > > > > > > ```
> > > > > > > > > > > > On 9 May 2019,
> > > > > > > > > > > > 
> > > > > > > > > > > > ```
> > > > > > > > > > > > 
> > > > > > > > > > > > at 14:28,  
> > > > > > > > > > > > Heather  
> > > > > > > > > > > > Broccard-Bell  
> > > > > > > > > > > > (hebell@ucsd.edu  
> > > > > > > > > > > > via csgnet  
> > > > > > > > > > > > Mailing List)  
> > > > > > > > > > > > \<csgnet@lists.illinois.edu \>  
> > > > > > > > > > > > wrote:
> 
> > > > > > > > > > > > >
> 
> > > > > > > > > > > > > ```
> > > > > > > > > > > > > I
> > > > > > > > > > > > > 
> > > > > > > > > > > > > ```
> > > > > > > > > > > > > 
> > > > > > > > > > > > > suspect that  
> > > > > > > > > > > > > the attached  
> > > > > > > > > > > > > (Aruin, 2003)  
> > > > > > > > > > > > > paper goes  
> > > > > > > > > > > > > some way  
> > > > > > > > > > > > > toward  
> > > > > > > > > > > > > reconciling  
> > > > > > > > > > > > > the  
> > > > > > > > > > > > > “invariant,  
> > > > > > > > > > > > > pre-programmed”  
> > > > > > > > > > > > > feedforward  
> > > > > > > > > > > > > conceptualization  
> > > > > > > > > > > > > with the  
> > > > > > > > > > > > > actual  
> > > > > > > > > > > > > phenomenon:  
> > > > > > > > > > > > > namely, it’s  
> > > > > > > > > > > > > not really  
> > > > > > > > > > > > > invariant (or,  
> > > > > > > > > > > > > well, it’s not  
> > > > > > > > > > > > > invariant in  
> > > > > > > > > > > > > that there is  
> > > > > > > > > > > > > a  
> > > > > > > > > > > > > pre-programmed  
> > > > > > > > > > > > > set of muscles  
> > > > > > > > > > > > > activated in a  
> > > > > > > > > > > > > pre-programmed  
> > > > > > > > > > > > > way). So, I  
> > > > > > > > > > > > > suspect that  
> > > > > > > > > > > > > some of the  
> > > > > > > > > > > > > problem in the  
> > > > > > > > > > > > > “mainstream”  
> > > > > > > > > > > > > is semantic.
> 
> > > > > > > > > > > > > ```
> > > > > > > > > > > > > Anyway,
> > > > > > > > > > > > > 
> > > > > > > > > > > > > ```
> > > > > > > > > > > > > 
> > > > > > > > > > > > > long (~500 ms)  
> > > > > > > > > > > > > stimulation of  
> > > > > > > > > > > > > motor cortex  
> > > > > > > > > > > > > has already  
> > > > > > > > > > > > > demonstrated  
> > > > > > > > > > > > > that “motor  
> > > > > > > > > > > > > output” seems  
> > > > > > > > > > > > > to be about  
> > > > > > > > > > > > > goals, and not  
> > > > > > > > > > > > > specific,  
> > > > > > > > > > > > > muscle-by-muscle  
> > > > > > > > > > > > > motor programs  
> > > > > > > > > > > > > (see Graziano,  
> > > > > > > > > > > > > 2002;  
> > > > > > > > > > > > > attached), and  
> > > > > > > > > > > > > really the  
> > > > > > > > > > > > > only way you  
> > > > > > > > > > > > > could get that  
> > > > > > > > > > > > > to work is  
> > > > > > > > > > > > > hierarchical  
> > > > > > > > > > > > > control with  
> > > > > > > > > > > > > continuous  
> > > > > > > > > > > > > feedback…
> 
> > > > > > > > > > > > > On Wed, May 8, 2019, 21:16 Martin Taylor \<csgnet@lists.illinois.edu \> \> \> \> \> \> \> \> \> \> \> \> \> wrote:
> 
> > > > > > > > > > > > > > [Martin Taylor  
> > > > > > > > > > > > > > 2019.05.09.00.09]
> > > > > > > > > > > > > > 
> > > > > > > > > > > > > > > ```
> > > > > > > > > > > > > > > [Rick
> > > > > > > > > > > > > > > 
> > > > > > > > > > > > > > > ```
> > > > > > > > > > > > > > > 
> > > > > > > > > > > > > > > Marken  
> > > > > > > > > > > > > > > 2019-05-08\_17:57:30]
> 
> > > > > > > > > > > > > > >
> 
> > > > > > > > > > > > > > > ```
> > > > > > > > > > > > > > > RM: Some
> > > > > > > > > > > > > > > 
> > > > > > > > > > > > > > > ```
> > > > > > > > > > > > > > > 
> > > > > > > > > > > > > > > time ago  
> > > > > > > > > > > > > > > Heather  
> > > > > > > > > > > > > > > Broccard-Bell  
> > > > > > > > > > > > > > > asked me what  
> > > > > > > > > > > > > > > the PCT  
> > > > > > > > > > > > > > > explanation  
> > > > > > > > > > > > > > > might be of a  
> > > > > > > > > > > > > > > behavior that  
> > > > > > > > > > > > > > > looks like a  
> > > > > > > > > > > > > > > pretty robust  
> > > > > > > > > > > > > > > example of  
> > > > > > > > > > > > > > > anticipatory  
> > > > > > > > > > > > > > > (or  
> > > > > > > > > > > > > > > feedforward)  
> > > > > > > > > > > > > > > control.  
> > > > > > > > > > > > > > > Here’s how  
> > > > > > > > > > > > > > > Heather  
> > > > > > > > > > > > > > > described it  
> > > > > > > > > > > > > > > to me:
> 
> > > > > > > > > > > > > > >
> 
> > > > > > > > > > > > > > > > ```
> > > > > > > > > > > > > > > > HB-B:
> > > > > > > > > > > > > > > > 
> > > > > > > > > > > > > > > > ```
> > > > > > > > > > > > > > > > 
> > > > > > > > > > > > > > > > I was reading  
> > > > > > > > > > > > > > > > about this  
> > > > > > > > > > > > > > > > finding (and  
> > > > > > > > > > > > > > > > perhaps you  
> > > > > > > > > > > > > > > > are already  
> > > > > > > > > > > > > > > > familiar)  
> > > > > > > > > > > > > > > > that, if if  
> > > > > > > > > > > > > > > > you measure  
> > > > > > > > > > > > > > > > muscle  
> > > > > > > > > > > > > > > > activation  
> > > > > > > > > > > > > > > > during  
> > > > > > > > > > > > > > > > behavior, you  
> > > > > > > > > > > > > > > > often see  
> > > > > > > > > > > > > > > > compensatory  
> > > > > > > > > > > > > > > > activation of  
> > > > > > > > > > > > > > > > the axial  
> > > > > > > > > > > > > > > > musculature  
> > > > > > > > > > > > > > > > well before  
> > > > > > > > > > > > > > > > you get  
> > > > > > > > > > > > > > > > activation in  
> > > > > > > > > > > > > > > > the muscles  
> > > > > > > > > > > > > > > > that direct  
> > > > > > > > > > > > > > > > the part of  
> > > > > > > > > > > > > > > > the body that  
> > > > > > > > > > > > > > > > does the thing  
> > > > > > > > > > > > > > > > you’re focused  
> > > > > > > > > > > > > > > > on. For  
> > > > > > > > > > > > > > > > example, they  
> > > > > > > > > > > > > > > > trained cats  
> > > > > > > > > > > > > > > > to bat at a  
> > > > > > > > > > > > > > > > target with  
> > > > > > > > > > > > > > > > their  
> > > > > > > > > > > > > > > > forepaw. \*\* Well  
> > > > > > > > > > > > > > > > before the  
> > > > > > > > > > > > > > > > limb/forepaw  
> > > > > > > > > > > > > > > > muscles are  
> > > > > > > > > > > > > > > > active, there  
> > > > > > > > > > > > > > > > is activation  
> > > > > > > > > > > > > > > > in the trunk  
> > > > > > > > > > > > > > > > musculature,  
> > > > > > > > > > > > > > > > seemingly  
> > > > > > > > > > > > > > > > anticipating  
> > > > > > > > > > > > > > > > the requisite  
> > > > > > > > > > > > > > > > compensatory  
> > > > > > > > > > > > > > > > stabilization  
> > > > > > > > > > > > > > > > that will  
> > > > > > > > > > > > > > > > become  
> > > > > > > > > > > > > > > > necessary when  
> > > > > > > > > > > > > > > > the forepaw is  
> > > > > > > > > > > > > > > > lifted. \*\* I  
> > > > > > > > > > > > > > > > am wondering  
> > > > > > > > > > > > > > > > what a PCT  
> > > > > > > > > > > > > > > > perspective  
> > > > > > > > > > > > > > > > might be on  
> > > > > > > > > > > > > > > > that? What is  
> > > > > > > > > > > > > > > > the relevant  
> > > > > > > > > > > > > > > > controlled  
> > > > > > > > > > > > > > > > variable,  
> > > > > > > > > > > > > > > > since the  
> > > > > > > > > > > > > > > > thing that  
> > > > > > > > > > > > > > > > actually  
> > > > > > > > > > > > > > > > changes  
> > > > > > > > > > > > > > > > sensory input  
> > > > > > > > > > > > > > > > that should  
> > > > > > > > > > > > > > > > activate  
> > > > > > > > > > > > > > > > control  
> > > > > > > > > > > > > > > > architecture  
> > > > > > > > > > > > > > > > hasn’t yet  
> > > > > > > > > > > > > > > > happened? Am  
> > > > > > > > > > > > > > > > I missing  
> > > > > > > > > > > > > > > > something? It  
> > > > > > > > > > > > > > > > appears to be  
> > > > > > > > > > > > > > > > a rather  
> > > > > > > > > > > > > > > > robust  
> > > > > > > > > > > > > > > > finding.[emphasis  
> > > > > > > > > > > > > > > > mine–RM]
> 
> > > > > > > > > > > > > > > …
> 
> > > > > > > > > > > > > > > ```
> > > > > > > > > > > > > > > RM:
> > > > > > > > > > > > > > > 
> > > > > > > > > > > > > > > ```
> > > > > > > > > > > > > > > 
> > > > > > > > > > > > > > > I am posting  
> > > > > > > > > > > > > > > this to you  
> > > > > > > > > > > > > > > experts on PCT  
> > > > > > > > > > > > > > > (with  
> > > > > > > > > > > > > > > Heather’s  
> > > > > > > > > > > > > > > permission)  
> > > > > > > > > > > > > > > because I  
> > > > > > > > > > > > > > > think this is  
> > > > > > > > > > > > > > > a very  
> > > > > > > > > > > > > > > interesting  
> > > > > > > > > > > > > > > discovery that  
> > > > > > > > > > > > > > > seems to pose  
> > > > > > > > > > > > > > > a challenge to  
> > > > > > > > > > > > > > > PCT and I  
> > > > > > > > > > > > > > > would like to  
> > > > > > > > > > > > > > > see what you  
> > > > > > > > > > > > > > > think about  
> > > > > > > > > > > > > > > this.
> 
> > > > > > > > > > > > > > ```
> > > > > > > > > > > > > > Here is 
> > > > > > > > > > > > > > 
> > > > > > > > > > > > > > ```
> > > > > > > > > > > > > > 
> > > > > > > > > > > > > > section of  
> > > > > > > > > > > > > > what I wrote  
> > > > > > > > > > > > > > to Heather on  
> > > > > > > > > > > > > > this question  
> > > > > > > > > > > > > > April 12.
> > > > > > > > > > > > > > 
> > > > > > > > > > > > > > ```
> > > > > > > > > > > > > > --------
> > > > > > > > > > > > > > 
> > > > > > > > > > > > > > [Here is a]
> > > > > > > > > > > > > > 
> > > > > > > > > > > > > > ```
> > > > > > > > > > > > > > 
> > > > > > > > > > > > > > quick and  
> > > > > > > > > > > > > > dirty PCT  
> > > > > > > > > > > > > > approach. I  
> > > > > > > > > > > > > > start with the  
> > > > > > > > > > > > > > intention to  
> > > > > > > > > > > > > > bat at the  
> > > > > > > > > > > > > > target, which  
> > > > > > > > > > > > > > would set a  
> > > > > > > > > > > > > > reference for  
> > > > > > > > > > > > > > a sequence  
> > > > > > > > > > > > > > that could  
> > > > > > > > > > > > > > crudely be  
> > > > > > > > > > > > > > taken as  
> > > > > > > > > > > > > > “store energy,  
> > > > > > > > > > > > > > set trigger,  
> > > > > > > > > > > > > > wait, release  
> > > > > > > > > > > > > > energy when  
> > > > > > > > > > > > > > required”, or  
> > > > > > > > > > > > > > in a more  
> > > > > > > > > > > > > > general sense  
> > > > > > > > > > > > > > “Prepare,  
> > > > > > > > > > > > > > wait,  
> > > > > > > > > > > > > > execute”. You  
> > > > > > > > > > > > > > call the  
> > > > > > > > > > > > > > storage  
> > > > > > > > > > > > > > “prestabilizing”,  
> > > > > > > > > > > > > > but I think  
> > > > > > > > > > > > > > Powers would  
> > > > > > > > > > > > > > have called  
> > > > > > > > > > > > > > that a  
> > > > > > > > > > > > > > “dormitive  
> > > > > > > > > > > > > > principle”  
> > > > > > > > > > > > > > that just  
> > > > > > > > > > > > > > labels what  
> > > > > > > > > > > > > > happens  
> > > > > > > > > > > > > > without in any  
> > > > > > > > > > > > > > way explaining  
> > > > > > > > > > > > > > how or why.  
> > > > > > > > > > > > > > The  
> > > > > > > > > > > > > > “stabilizing”  
> > > > > > > > > > > > > > is postural  
> > > > > > > > > > > > > > control of the  
> > > > > > > > > > > > > > normal kind,  
> > > > > > > > > > > > > > the same as  
> > > > > > > > > > > > > > would happen  
> > > > > > > > > > > > > > if you pushed  
> > > > > > > > > > > > > > the cat. If  
> > > > > > > > > > > > > > you have seen  
> > > > > > > > > > > > > > a video of the  
> > > > > > > > > > > > > > “Big Dog”  
> > > > > > > > > > > > > > robot, you  
> > > > > > > > > > > > > > have seen this  
> > > > > > > > > > > > > > kind of  
> > > > > > > > > > > > > > stabilization.
> > > > > > > > > > > > > > 
> > > > > > > > > > > > > > ```
> > > > > > > > > > > > > > The magician
> > > > > > > > > > > > > > 
> > > > > > > > > > > > > > ```
> > > > > > > > > > > > > > 
> > > > > > > > > > > > > > Harry Houdini  
> > > > > > > > > > > > > > died because  
> > > > > > > > > > > > > > he hadn’t  
> > > > > > > > > > > > > > stored the  
> > > > > > > > > > > > > > energy to  
> > > > > > > > > > > > > > resist a blow  
> > > > > > > > > > > > > > to his abdomen  
> > > > > > > > > > > > > > when someone  
> > > > > > > > > > > > > > hit him before  
> > > > > > > > > > > > > > he was  
> > > > > > > > > > > > > > prepared,  
> > > > > > > > > > > > > > which he did  
> > > > > > > > > > > > > > by tensing  
> > > > > > > > > > > > > > (supplying  
> > > > > > > > > > > > > > energy to) the  
> > > > > > > > > > > > > > stomach  
> > > > > > > > > > > > > > muscles. He  
> > > > > > > > > > > > > > had offered a  
> > > > > > > > > > > > > > general  
> > > > > > > > > > > > > > challenge that  
> > > > > > > > > > > > > > nobody could  
> > > > > > > > > > > > > > hit him there  
> > > > > > > > > > > > > > hard enough to  
> > > > > > > > > > > > > > hurt him, but  
> > > > > > > > > > > > > > the hitter was  
> > > > > > > > > > > > > > supposed to do  
> > > > > > > > > > > > > > it in a formal  
> > > > > > > > > > > > > > kind of way,  
> > > > > > > > > > > > > > when he was  
> > > > > > > > > > > > > > prepared. When  
> > > > > > > > > > > > > > the fatal blow  
> > > > > > > > > > > > > > was struck,  
> > > > > > > > > > > > > > his muscles  
> > > > > > > > > > > > > > had  
> > > > > > > > > > > > > > insufficient  
> > > > > > > > > > > > > > stored energy  
> > > > > > > > > > > > > > to oppose the  
> > > > > > > > > > > > > > shock energy  
> > > > > > > > > > > > > > in the blow.
> > > > > > > > > > > > > > 
> > > > > > > > > > > > > > ```
> > > > > > > > > > > > > > I think the
> > > > > > > > > > > > > > 
> > > > > > > > > > > > > > ```
> > > > > > > > > > > > > > 
> > > > > > > > > > > > > > actual  
> > > > > > > > > > > > > > stabilization  
> > > > > > > > > > > > > > is simply the  
> > > > > > > > > > > > > > use of some of  
> > > > > > > > > > > > > > the  
> > > > > > > > > > > > > > pre-tensioned  
> > > > > > > > > > > > > > stored energy  
> > > > > > > > > > > > > > in normal  
> > > > > > > > > > > > > > postural  
> > > > > > > > > > > > > > control  
> > > > > > > > > > > > > > against a  
> > > > > > > > > > > > > > force that  
> > > > > > > > > > > > > > would be  
> > > > > > > > > > > > > > destabilizing,  
> > > > > > > > > > > > > > but instead of  
> > > > > > > > > > > > > > the control  
> > > > > > > > > > > > > > being entirely  
> > > > > > > > > > > > > > to oppose a  
> > > > > > > > > > > > > > sensed  
> > > > > > > > > > > > > > disturbance,  
> > > > > > > > > > > > > > it is part of  
> > > > > > > > > > > > > > the output  
> > > > > > > > > > > > > > side support  
> > > > > > > > > > > > > > of the  
> > > > > > > > > > > > > > sequence  
> > > > > > > > > > > > > > controller.  
> > > > > > > > > > > > > > The “bat” is  
> > > > > > > > > > > > > > not simply  
> > > > > > > > > > > > > > sending  
> > > > > > > > > > > > > > reference  
> > > > > > > > > > > > > > values to  
> > > > > > > > > > > > > > muscles that  
> > > > > > > > > > > > > > move the paw  
> > > > > > > > > > > > > > relative to  
> > > > > > > > > > > > > > the torso, it  
> > > > > > > > > > > > > > is sending  
> > > > > > > > > > > > > > reference  
> > > > > > > > > > > > > > values to all  
> > > > > > > > > > > > > > the postural  
> > > > > > > > > > > > > > muscles in a  
> > > > > > > > > > > > > > temporal  
> > > > > > > > > > > > > > pattern that  
> > > > > > > > > > > > > > has been  
> > > > > > > > > > > > > > reorganized  
> > > > > > > > > > > > > > into the  
> > > > > > > > > > > > > > control  
> > > > > > > > > > > > > > hierarchy in  
> > > > > > > > > > > > > > the same way  
> > > > > > > > > > > > > > as a trained  
> > > > > > > > > > > > > > athlete such  
> > > > > > > > > > > > > > as a ballerina  
> > > > > > > > > > > > > > coordinates  
> > > > > > > > > > > > > > the timings  
> > > > > > > > > > > > > > and strengths  
> > > > > > > > > > > > > > of her muscle  
> > > > > > > > > > > > > > movements so  
> > > > > > > > > > > > > > that what an  
> > > > > > > > > > > > > > observer calls  
> > > > > > > > > > > > > > “the” action  
> > > > > > > > > > > > > > doesn’t  
> > > > > > > > > > > > > > interfere with  
> > > > > > > > > > > > > > her balance.
> > > > > > > > > > > > > > 
> > > > > > > > > > > > > > ```
> > > > > > > > > > > > > > Anyway, those
> > > > > > > > > > > > > > 
> > > > > > > > > > > > > > ```
> > > > > > > > > > > > > > 
> > > > > > > > > > > > > > are my first  
> > > > > > > > > > > > > > thoughts on  
> > > > > > > > > > > > > > the question,  
> > > > > > > > > > > > > > before  
> > > > > > > > > > > > > > breakfast.
> > > > > > > > > > > > > > 
> > > > > > > > > > > > > > ```
> > > > > > > > > > > > > > -------
> > > > > > > > > > > > > > 
> > > > > > > > > > > > > > I haven't
> > > > > > > > > > > > > > 
> > > > > > > > > > > > > > ```
> > > > > > > > > > > > > > 
> > > > > > > > > > > > > > considered the  
> > > > > > > > > > > > > > problem since  
> > > > > > > > > > > > > > then, but I  
> > > > > > > > > > > > > > thought I  
> > > > > > > > > > > > > > might offer  
> > > > > > > > > > > > > > the  
> > > > > > > > > > > > > > suggestion.
> > > > > > > > > > > > > > 
> > > > > > > > > > > > > > ```
> > > > > > > > > > > > > > The saying
> > > > > > > > > > > > > > 
> > > > > > > > > > > > > > ```
> > > > > > > > > > > > > > 
> > > > > > > > > > > > > > “Reculer pour  
> > > > > > > > > > > > > > mieux sauter”  
> > > > > > > > > > > > > > seems to be  
> > > > > > > > > > > > > > about the same  
> > > > > > > > > > > > > > phenomenon.
> > > > > > > > > > > > > > 
> > > > > > > > > > > > > > ```
> > > > > > > > > > > > > > Martin
> > > > > > > > > > > > > > 
> > > > > > > > > > > > > > ```
> 
> > > > > > > > > > > > > \<aruin2003.pdf\>
> 
> > > > > > > > > > > > > \<graziano2002.pdf\>
> 
> > > > > > > > > >
> 
> > > > > > > > >
> 
> > > > > > > > > –  
> > > > > > > > > Heather  
> > > > > > > > > C.  
> > > > > > > > > Broccard-Bell,  
> > > > > > > > > Ph.D.
> 
> > > > > > > > >
> 
> > > > > > > > > Adjunct Assistant Professor
> 
> > > > > > > > > ```
> > > > > > > > > Department
> > > > > > > > > 
> > > > > > > > > ```
> > > > > > > > > 
> > > > > > > > > of  
> > > > > > > > > Psychological  
> > > > > > > > > Sciences
> 
> > > > > > > > > ```
> > > > > > > > > University
> > > > > > > > > 
> > > > > > > > > ```
> > > > > > > > > 
> > > > > > > > > of San Diego
> 
> > > > > > > > >
> 
> > > > > > > > > ```
> > > > > > > > > Visiting
> > > > > > > > > 
> > > > > > > > > ```
> > > > > > > > > 
> > > > > > > > > Scholar
> 
> > > > > > > > > ```
> > > > > > > > > The
> > > > > > > > > 
> > > > > > > > > ```
> > > > > > > > > 
> > > > > > > > > role of noise  
> > > > > > > > > / variability  
> > > > > > > > > in complex,  
> > > > > > > > > adaptive  
> > > > > > > > > systems
> 
> > > > > > > > > ```
> > > > > > > > > Nieh
> > > > > > > > > 
> > > > > > > > > ```
> > > > > > > > > 
> > > > > > > > > Honey Bee Lab
> 
> > > > > > > > > ```
> > > > > > > > > Division
> > > > > > > > > 
> > > > > > > > > ```
> > > > > > > > > 
> > > > > > > > > of Biological  
> > > > > > > > > Sciences;  
> > > > > > > > > Section of  
> > > > > > > > > Ecology,  
> > > > > > > > > Behavior, and  
> > > > > > > > > Evolution
> 
> > > > > > > > > ```
> > > > > > > > > University
> > > > > > > > > 
> > > > > > > > > ```
> > > > > > > > > 
> > > > > > > > > of California  
> > > > > > > > > San Diego
> 
> > > > > > > > > ```
> > > > > > > > > 619.757.4694
> > > > > > > > > 
> > > > > > > > > ```
> 
> > > > > > > >
> 
> > > > > > > > –  
> > > > > > > > Heather  
> > > > > > > > C.  
> > > > > > > > Broccard-Bell,  
> > > > > > > > Ph.D.
> 
> > > > > > > >
> 
> > > > > > > > Adjunct Assistant Professor
> 
> > > > > > > > ```
> > > > > > > > Department
> > > > > > > > 
> > > > > > > > ```
> > > > > > > > 
> > > > > > > > of  
> > > > > > > > Psychological  
> > > > > > > > Sciences
> 
> > > > > > > > ```
> > > > > > > > University
> > > > > > > > 
> > > > > > > > ```
> > > > > > > > 
> > > > > > > > of San Diego
> 
> > > > > > > >
> 
> > > > > > > > ```
> > > > > > > > Visiting
> > > > > > > > 
> > > > > > > > ```
> > > > > > > > 
> > > > > > > > Scholar
> 
> > > > > > > > ```
> > > > > > > > The
> > > > > > > > 
> > > > > > > > ```
> > > > > > > > 
> > > > > > > > role of noise  
> > > > > > > > / variability  
> > > > > > > > in complex,  
> > > > > > > > adaptive  
> > > > > > > > systems
> 
> > > > > > > > ```
> > > > > > > > Nieh
> > > > > > > > 
> > > > > > > > ```
> > > > > > > > 
> > > > > > > > Honey Bee Lab
> 
> > > > > > > > ```
> > > > > > > > Division
> > > > > > > > 
> > > > > > > > ```
> > > > > > > > 
> > > > > > > > of Biological  
> > > > > > > > Sciences;  
> > > > > > > > Section of  
> > > > > > > > Ecology,  
> > > > > > > > Behavior, and  
> > > > > > > > Evolution
> 
> > > > > > > > ```
> > > > > > > > University
> > > > > > > > 
> > > > > > > > ```
> > > > > > > > 
> > > > > > > > of California  
> > > > > > > > San Diego
> 
> > > > > > > > ```
> > > > > > > > 619.757.4694
> > > > > > > > 
> > > > > > > > ```
> 
> > > > > > >
> 
> > > > > >
> 
> > > > > > –  
> > > > > > Heather  
> > > > > > C.  
> > > > > > Broccard-Bell,  
> > > > > > Ph.D.
> 
> > > > > >
> 
> > > > > > Adjunct Assistant Professor
> 
> > > > > > ```
> > > > > > Department
> > > > > > 
> > > > > > ```
> > > > > > 
> > > > > > of  
> > > > > > Psychological  
> > > > > > Sciences
> 
> > > > > > ```
> > > > > > University
> > > > > > 
> > > > > > ```
> > > > > > 
> > > > > > of San Diego
> 
> > > > > >
> 
> > > > > > ```
> > > > > > Visiting
> > > > > > 
> > > > > > ```
> > > > > > 
> > > > > > Scholar
> 
> > > > > > ```
> > > > > > The
> > > > > > 
> > > > > > ```
> > > > > > 
> > > > > > role of noise  
> > > > > > / variability  
> > > > > > in complex,  
> > > > > > adaptive  
> > > > > > systems
> 
> > > > > > ```
> > > > > > Nieh
> > > > > > 
> > > > > > ```
> > > > > > 
> > > > > > Honey Bee Lab
> 
> > > > > > ```
> > > > > > Division
> > > > > > 
> > > > > > ```
> > > > > > 
> > > > > > of Biological  
> > > > > > Sciences;  
> > > > > > Section of  
> > > > > > Ecology,  
> > > > > > Behavior, and  
> > > > > > Evolution
> 
> > > > > > ```
> > > > > > University
> > > > > > 
> > > > > > ```
> > > > > > 
> > > > > > of California  
> > > > > > San Diego
> 
> > > > > > ```
> > > > > > 619.757.4694
> > > > > > 
> > > > > > ```

---

<div class="post-metadata">

**Author:** ![MartinT](http://discourse.iapct.org/letter_avatar_proxy/v4/letter/m/ee7513/32.png) [@MartinT](http://discourse.iapct.org/u/MartinT)\
**Post date:** [May 10, 2019, 9:17pm UTC](http://discourse.iapct.org/t/anticipatory-postural-control/1164/29 "2019-05-10T21:17:20Z")

</div>

[Martin Taylor 2019.05.10.16.51]

> **···**
>
> On 2019-05-10 4:14 PM, Bill Leach  
> ( via csgnet Mailing List) wrote:  
> Bill, have you checked whether people all around the globe would  
> see this message if they search for “2019-05-10 4:14 PM, Bill  
> Leach” in order to reference it in a posting to this thread? You  
> may remember that we went through this exercise a few years ago,  
> and because the answer was no, we agreed that we would head each  
> message with a unique ID. The form wouldn’t matter, but the [Name  
> Date/time] format is convenient and can apparently be automated on  
> a PC – perhaps also on a Mac, though I have never tried. But I  
> guess that if you don’t want your message to be searchable in an  
> archive by people in other time zones, there’s nothing further to  
> be said.
> 
> [wrleach@cableone.net](mailto:wrleach@cableone.net)
> 
> > Rick,
> 
> > > [Rick Marken 2019-05-10\_11:53:31]
> 
> > >
> 
> > > ```
> > > RM: Well, this has certainly been an
> > > 
> > > ```
> > > 
> > > interesting thread so far. I’m happy to see that there  
> > > is a kind of consensus that the PCT explanation of  
> > > apparent “anticipatory” behavior is that it is likely to  
> > > be actions aimed at controlling a “higher level”  
> > > controlled variable. The landslide was started by Henry  
> > > Yin who said:
> > > 
> > > ```
> > > > HY: There’s no conflict between negative feedback
> > > 
> > > ```
> > > 
> > > and anticipatory behavior. The real question is what  
> > > kind of CV do you need to produce such behavior.
> > > 
> > > ```
> > > RM: I think this is the right question: what kind of CV
> > > 
> > > ```
> > > 
> > > would an organism be controlling that would result in  
> > > your seeing such apparently “anticipatory” behavior.  
> > > Martin suggests that the CV is a sequence:
> > > 
> > > ```
> > > > MT: [Here is a] quick and dirty PCT approach. I
> > > 
> > > ```
> > > 
> > > start with the intention to bat at the target, which  
> > > would set a reference for a sequence that could crudely  
> > > be taken as “store energy, set trigger, wait, release  
> > > energy when required”, or in a more general sense  
> > > “Prepare, wait, execute”.
> 
> > > ```
> > > RM: And Erling agrees:
> > > 
> > > >
> > > 
> > > > EJ: I rather like Martin's proposal for
> > > 
> > > ```
> > > 
> > > controlling a prior stage in a sequence.
> > > 
> > > ```
> > > RM: And I agree that the CV is something like a
> > > 
> > > ```
> > > 
> > > sequence, but not like the one Martin suggests. In the  
> > > case of the an anticipatory postural adjustments (APAs)  
> > > seen in the cat’s reaching behavior (described in the  
> > > Sheppen and Drew paper), it seems to me that the  
> > > controlled variable is the “reach” itself – an event –  
> > > like a “golf swing”. An event differs from a sequence  
> > > only inasmuch as it is a continuously changing sequence  
> > > of lower level perceptions that is defined over time.  
> > > The “reach” requires making postural changes over time  
> > > that get the paw to the intended destination while  
> > > maintaining balance. So I see the APAs as the initial  
> > > components of this “reach” event.
> 
> > ```
> > I could agree with you here Rick but only
> > 
> > ```
> > 
> > if Martin’s intent was to exclude continuous feedback control,  
> > which I believe was NOT the case. I admit that his " Prepare, wait, execute" rather reads that way  
> > but that is how it would appear to the observer. The simplest  
> > form of sequencing would be 2 steps even though in his example  
> > he included more steps where it would not be at all  
> > unreasonable to infer that waiting and executing were part of  
> > that sequence.
> 
> ```
> In other messages I have used a two-step
> 
> ```
> 
> sequence. But I think it is important for the cat, an athlete, or  
> an archer, to spend some time storing energy that can be released  
> quickly, rather than at the rate at which it can be generated.  
> Hence there should be a wait phase, implicit in storing enough  
> energy to perform the quick energy release. It is not a separate  
> phase in the sequence I was thinking of. The next phase of the  
> sequence is sending reference values to whatever control loops are  
> involved in making the movement. Those certainly are continuous,  
> but the sequence must have two distinct and separate steps.
> 
> ```
> Most discussions of PCT ignore energy, but no action output to the
> 
> ```
> 
> Real Reality environment can occur without dissipating some  
> energy. The question of “pre-tensioning” is about how fast the  
> energy is dissipated to the environment. I don’t believe that the  
> basic hierarchy includes perceptual control of the energy  
> available to lower-level control loops to which this one sends  
> reference values. If I’m wrong, I’d like to know in what respect.  
> But perceptual control of a rapid event is not possible if  
> insufficient energy is available to power the action. Accordingly,  
> I would be surprised if evolution/reorganization had not provided  
> some way to inhibit the output onset of an event until sufficient  
> energy was available to the control loops involved to allow the  
> event to complete as an instance of continuous control.
> 
> > ```
> > Pre-tensioning muscles certainly does not
> > 
> > ```
> > 
> > have to be driven by anticipation. It could just be wired to  
> > be a 2 step process.
> 
> > bill
> 
> Right.
> 
> ```
> Martin
> 
> ```
> 
> > 
> 
> >

---

<div class="post-metadata">

**Author:** ![bleach](http://discourse.iapct.org/user_avatar/discourse.iapct.org/bleach/32/51_2.png) [@bleach](http://discourse.iapct.org/u/bleach)\
**Post date:** [May 10, 2019, 9:49pm UTC](http://discourse.iapct.org/t/anticipatory-postural-control/1164/30 "2019-05-10T21:49:47Z")

</div>

[Bill Leach 2019.05.10.15.38]

```
  That discussion may have happened when I had a death in the

```

family. In any event, I missed it so, OK thanks. I presume that  
I can automate that, I’ll have to see. As you no doubt concluded,  
I thought that you were referring to the ID that is a part of the  
message headers per the RFC.

bill

> **···**
>
> On 5/10/19 3:17 PM, Martin Taylor  
> ( via csgnet Mailing List) wrote:
> 
> [mmt-csg@mmtaylor.net](mailto:mmt-csg@mmtaylor.net)
> 
> > [Martin Taylor 2019.05.10.16.51]
> 
> > 
> 
> ```
> On 2019-05-10 4:14 PM, Bill Leach (
> 
> ```
> 
> via csgnet Mailing List) wrote:  
> Bill, have you checked whether people all around the globe would  
> see this message if they search for “2019-05-10 4:14 PM, Bill  
> Leach” in order to reference it in a posting to this thread? You  
> may remember that we went through this exercise a few years ago,  
> and because the answer was no, we agreed that we would head each  
> message with a unique ID. The form wouldn’t matter, but the  
> [Name Date/time] format is convenient and can apparently be  
> automated on a PC – perhaps also on a Mac, though I have never  
> tried. But I guess that if you don’t want your message to be  
> searchable in an archive by people in other time zones, there’s  
> nothing further to be said.
> 
> [wrleach@cableone.net](mailto:wrleach@cableone.net)
> 
> > Rick,
> 
> > > [Rick Marken 2019-05-10\_11:53:31]
> 
> > >
> 
> > > ```
> > > RM: Well, this has certainly been an
> > > 
> > > ```
> > > 
> > > interesting thread so far. I’m happy to see that there  
> > > is a kind of consensus that the PCT explanation of  
> > > apparent “anticipatory” behavior is that it is likely  
> > > to be actions aimed at controlling a “higher level”  
> > > controlled variable. The landslide was started by  
> > > Henry Yin who said:
> > > 
> > > ```
> > > > HY: There’s no conflict between negative feedback
> > > 
> > > ```
> > > 
> > > and anticipatory behavior. The real question is what  
> > > kind of CV do you need to produce such behavior.
> > > 
> > > ```
> > > RM: I think this is the right question: what kind of
> > > 
> > > ```
> > > 
> > > CV would an organism be controlling that would result  
> > > in your seeing such apparently “anticipatory”  
> > > behavior. Martin suggests that the CV is a sequence:
> > > 
> > > ```
> > > > MT: [Here is a] quick and dirty PCT approach. I
> > > 
> > > ```
> > > 
> > > start with the intention to bat at the target, which  
> > > would set a reference for a sequence that could  
> > > crudely be taken as “store energy, set trigger, wait,  
> > > release energy when required”, or in a more general  
> > > sense “Prepare, wait, execute”.
> 
> > > ```
> > > RM: And Erling agrees:
> > > 
> > > >
> > > 
> > > > EJ: I rather like Martin's proposal for
> > > 
> > > ```
> > > 
> > > controlling a prior stage in a sequence.
> > > 
> > > ```
> > > RM: And I agree that the CV is something like a
> > > 
> > > ```
> > > 
> > > sequence, but not like the one Martin suggests. In the  
> > > case of the an anticipatory postural adjustments  
> > > (APAs) seen in the cat’s reaching behavior (described  
> > > in the Sheppen and Drew paper), it seems to me that  
> > > the controlled variable is the “reach” itself – an  
> > > event – like a “golf swing”. An event differs from a  
> > > sequence only inasmuch as it is a continuously  
> > > changing sequence of lower level perceptions that is  
> > > defined over time. The “reach” requires making  
> > > postural changes over time that get the paw to the  
> > > intended destination while maintaining balance. So I  
> > > see the APAs as the initial components of this “reach”  
> > > event.
> 
> > ```
> > I could agree with you here Rick but
> > 
> > ```
> > 
> > only if Martin’s intent was to exclude continuous feedback  
> > control, which I believe was NOT the case. I admit that his  
> > " Prepare, wait, execute" rather  
> > reads that way but that is how it would appear to the  
> > observer. The simplest form of sequencing would be 2 steps  
> > even though in his example he included more steps where it  
> > would not be at all unreasonable to infer that waiting and  
> > executing were part of that sequence.
> 
> ```
> In other messages I have used a two-step
> 
> ```
> 
> sequence. But I think it is important for the cat, an athlete,  
> or an archer, to spend some time storing energy that can be  
> released quickly, rather than at the rate at which it can be  
> generated. Hence there should be a wait phase, implicit in  
> storing enough energy to perform the quick energy release. It is  
> not a separate phase in the sequence I was thinking of. The next  
> phase of the sequence is sending reference values to whatever  
> control loops are involved in making the movement. Those  
> certainly are continuous, but the sequence must have two  
> distinct and separate steps.
> 
> ```
> Most discussions of PCT ignore energy, but no action output to
> 
> ```
> 
> the Real Reality environment can occur without dissipating some  
> energy. The question of “pre-tensioning” is about how fast the  
> energy is dissipated to the environment. I don’t believe that  
> the basic hierarchy includes perceptual control of the energy  
> available to lower-level control loops to which this one sends  
> reference values. If I’m wrong, I’d like to know in what  
> respect. But perceptual control of a rapid event is not possible  
> if insufficient energy is available to power the action.  
> Accordingly, I would be surprised if evolution/reorganization  
> had not provided some way to inhibit the output onset of an  
> event until sufficient energy was available to the control loops  
> involved to allow the event to complete as an instance of  
> continuous control.
> 
> > ```
> > Pre-tensioning muscles certainly does
> > 
> > ```
> > 
> > not have to be driven by anticipation. It could just be  
> > wired to be a 2 step process.
> 
> > bill
> 
> Right.
> 
> ```
> Martin
> 
> ```
> 
> > 
> 
> >

---

<div class="post-metadata">

**Author:** ![rsmarken](http://discourse.iapct.org/user_avatar/discourse.iapct.org/rsmarken/32/3553_2.png) [@rsmarken](http://discourse.iapct.org/u/rsmarken)\
**Post date:** [May 11, 2019, 12:05am UTC](http://discourse.iapct.org/t/anticipatory-postural-control/1164/31 "2019-05-11T00:05:04Z")

</div>

[Rick Marken 2019-05-10\_17:04:34]

> HB: I kind of think a lot of the problem is semantic. Some seem to be upset by the term “prediction” or “anticipation”, and I think what Rick/Henry suggest is a reasonable explanation for a _mechanism_ for what most people would call anticipation/prediction. It can’t be magic :))

RM: The only time I get upset by terms like “prediction” and “anticipation” is when they give the wrong impression of how the PCT model explains some behaviors. This usually happens when it “looks like” a behavior involves “prediction” or “anticipation”.  For example, the behavior called “catching a fly ball” appears to involve “prediction” or “anticipation”. You can see it in the movements of the fielder in my baseball catch simulation ([https://www.mindreadings.com/ControlDemo/CatchXY.html](https://www.mindreadings.com/ControlDemo/CatchXY.html)). The fielder seems to be making “anticipatory field adjustments” (AFAs?) in anticipation of being in the proper position to catch the ball. But we have found that the fielder’s behavior can be accounted for quite well by a model that involves no prediction at all; the fielder in the ball catching demo gets to the correct position by controlling two present time perceptual variables: vertical and horizontal optical velocity.Â

RM: The PCT model I propose to account for the postural adjustments that seem to anticipate future disturbances (APAs) also involves no prediction. My model involves present time control of an event perception that I call “reach”; I didn’t define it very well because I don’t have a good idea of what it is but this event would be a _temporal pattern_ of proprioceptive sensations – sensed angles of the limbs, center of gravity, etc. This temporal pattern is a perceptual variable, just as a temporal pattern of phonemes is a perceptual variable. The “reach” control system I proposed uses variations in posture (including APAs), limb angles and muscle forces to bring this perceptual variable to the reference state (that I called “reach”) while protecting it from disturbances that can affect the perception at any point during its production. I’m conceiving this control as being analogous to controlling for saying a particular word, as described in the “Control of Sequence” chapter of B:CP. In that model of word production there is also no prediction involved; the perceptual function just “constructs” a word based on the sequence of phonemes (analogous to the postural adjustments occurring during a “reach”) that are produced by lower level systems. It doesn’t predict what phoneme is coming next.

RM: In order to test this model we really have to come up with a clearer definition of the proposed controlled variable – which I suppose could be called “reachness”. And it really would be good to have a working model of this behavior, if for no other reason than to show how a model that controls a variable that is _defined over time_ can be controlled. I believe that the most important way that PCT differs from other control models of the behavior of living systems is that it assumes that ALL behavior is control; And since control always involves the control of perception that means that simple behaviors involve the control of simple perceptions and complex behaviors involve the control of complex perceptions – and these are usually perceptions that are defined over sometimes considerable amounts of time. This is one of the main reasons why Bill proposed a hierarchy of perceptions. It was to account for the obviously hierarchical nature of behavior – behaviors “using” other behaviors to achieve their purposes; for example, using behaviors like running, throwing, catching and hitting to achieve the purpose of playing baseball – and for the fact that the behaviors that use other behaviors to achieve their purposes involve control of more complex perceptions than the behaviors that are being used;Â the perception controlled when “playing baseball” is much more complex (and defined over a much longer time period) than the perceptions controlled when running, throwing, catching and hitting.

> HB-B: We know that both humans and cats fail to show APAs if they are taken by surprise.Â

RM: Yes, I noticed that. From the perspective of my model, that would result from not setting the reference for “reach” or " bilateral arm movement" or whatever the event is. This happens a lot in my sport, racquetball. The ideal way to take a forehand shot is to do a lot of APAs that get you into position to take it off the back wall. But sometimes I get a shot that comes at me so fast that I don’t have time to set up for a “proper forehand shot” – no APAs needed – so I just do what I can to move the racket to the ball like a beginner. Â

RM: I hope this makes some sense because I think it would really be a great area for research on control of higher level perceptual variables – variables that are defined over time.Â

Best

Rick

> **···**
>
> On Fri, May 10, 2019 at 12:50 PM Heather Broccard-Bell [random.information.consultant@gmail.com](mailto:random.information.consultant@gmail.com) wrote:
> 
> > So yes, some environmental information serves to remove the surprise, kicking the control systems into gear. Is that (those) control system(s), dealing with the appearance of the target often used in the cat experiments to signal the upcoming stimulus, totally divorced from the “paw bat” ones? Should they be coupled? What happens if the expected stimulus never arrives, but the target remains? I guess there is fatigue at some point. What is the relevant question to ask?
> 
> > 
> 
> > In populations of upper motor neurons in motor and premotor cortex, there is often activity seconds before any movement is observed. What does that mean for control systems? That’s obviously not just delay. Those populations get input from… like everwhere. Motor cortex is bonkers! Â
> 
> > 
> 
> > 
> 
> > On Fri, May 10, 2019, 11:59 Richard Marken [csgnet@lists.illinois.edu](mailto:csgnet@lists.illinois.edu) wrote:
> 
> > > [Rick Marken 2019-05-10\_11:53:31]
> 
> > >
> 
> > > RM: Well, this has certainly been an interesting thread so far. I’m happy to see that there is a kind of consensus that the PCT explanation of apparent “anticipatory” behavior is that it is likely to be actions aimed at controlling a “higher level” controlled variable. The landslide was started by Henry Yin who said:
> > > 
> > > > HY: There’s no conflict between negative feedback and anticipatory behavior. The real question is what kind of CV do you need to produce such behavior.
> > > 
> > > RM: I think this is the right question: what kind of CV would an organism be controlling that would result in your seeing such apparently "anticipatory"Â behavior. Martin suggests that the CV is a sequence:
> > > 
> > > > MT: [Here is a] quick and dirty PCT approach. I start with the intention to bat at the target, which would set a reference for a sequence that could crudely be taken as “store energy, set trigger, wait, release energy when required”, or in a more general sense “Prepare, wait, execute”.
> 
> > > RM: And Erling agrees:
> > > 
> > > > EJ: Â I rather like Martin’s proposal for controlling a prior stage in a sequence. Â
> > > 
> > > RM: And I agree that the CV is something like a sequence, but not like the one Martin suggests. In the case of the an anticipatory postural adjustments (APAs) seen in the cat’s reaching behavior (described in the Sheppen and Drew paper), it seems to me that the controlled variable is the “reach” itself – an event – like a “golf swing”. An event differs from a sequence only inasmuch as it is a continuously changing sequence of lower level perceptions that is defined over time. The “reach” requires making postural changes over time that get the paw to the intended destination while maintaining balance. So I see the APAs as the initial components of this “reach” event.Â
> 
> > >
> 
> > > RM: I see these APA’s as being analogous to the initial muscular movements – for example, contraction of the diaphragm - that are involved in producing a word. These movements are not outputs produced in anticipation of a future disturbance but are the outputs in a control loop that is aimed at controlling a perception of the word. The word itself, like reach, is the controlled variable – a variable that is defined over time.Â
> 
> > >
> 
> > > RM: Because “reach” is defined over time it looks like the initial postural adjustments that are made to control this perception are anticipatory. But I believe that they are actually just like the outputs in any control loop – continuously acting to keep the controlled variable in a reference state, protected from disturbances. If this is the case – if APAs are actually the initial outputs of a control loop controlling a variable that is defied over time – then disturbances to these APA’s will be resisted. Heather mentions some data that is consistent with this view:
> > > 
> > > > NB-B: I suspect that the attached (Aruin, 2003) paper goes some way toward reconciling the “invariant, pre-programmed” feedforward conceptualization with the actual phenomenon: namely, it’s not really invariant (or, well, it’s not invariant in that there is a pre-programmed set of muscles activated in a pre-programmed way). Â
> 
> > > RM: I haven’t read the whole article carefully but apparently what Arium did was look to see whether variations in the initial the position of the body affected the nature of the APAs. And indeed it did. I see these variations in the initial position of the body as disturbances to a controlled variable (in Arium’s case it was “bilateral arm movement” rather than “reach”) and these disturbances are compensated for by the variations in the APAs.Â
> 
> > >
> 
> > > RM: Of course, the idea that APAs are the outputs in a control loop controlling a variable defined over time has to be subjected to far more tests. And control models should be built to show that control of a higher level perception, like “reach”, can lead to behavior that “looks” anticipatory. So there’s some general ideas for PCT research that would be a great place to start for researchers interested in doing research on purpose!
> 
> > >
> 
> > > BestÂ
> 
> > >
> 
> > > Rick
> 
> > > Â
> 
> > >
> 
> > >
> 
> > >
> 
> > > –  
> > > Richard S. MarkenÂ
> 
> > > "Perfection is achieved not when you have nothing more to add, but when you  
> > > have nothing left to take away.�  
> > > Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â --Antoine de Saint-Exupery
> 
> –  
> Richard S. MarkenÂ
> 
> "Perfection is achieved not when you have nothing more to add, but when you  
> have nothing left to take away.�  
> Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â --Antoine de Saint-Exupery

---

<div class="post-metadata">

**Author:** ![Heather\_Broccard-Bel](http://discourse.iapct.org/user_avatar/discourse.iapct.org/heather_broccard-bel/32/43_2.png) [@Heather\_Broccard-Bel](http://discourse.iapct.org/u/Heather_Broccard-Bel)\
**Post date:** [May 11, 2019, 3:06am UTC](http://discourse.iapct.org/t/anticipatory-postural-control/1164/32 "2019-05-11T03:06:52Z")

</div>

> I think this does make sense, and would be interesting to build. I am curious about a ‘critical experiment’ that would distinguish the PCT model from the mainstream account… although it does seem to be one of these phenomena that people have described without couching it in any particular theoretical framework, so this may not be possible.

> 

> > [Rick Marken 2019-05-10\_17:04:34]

> >

> > > HB: I kind of think a lot of the problem is semantic. Some seem to be upset by the term “prediction” or “anticipation”, and I think what Rick/Henry suggest is a reasonable explanation for a _mechanism_ for what most people would call anticipation/prediction. It can’t be magic :))

> >

> > RM: The only time I get upset by terms like “prediction” and “anticipation” is when they give the wrong impression of how the PCT model explains some behaviors. This usually happens when it “looks like” a behavior involves “prediction” or “anticipation”.  For example, the behavior called “catching a fly ball” appears to involve “prediction” or “anticipation”. You can see it in the movements of the fielder in my baseball catch simulation ([https://www.mindreadings.com/ControlDemo/CatchXY.html](https://www.mindreadings.com/ControlDemo/CatchXY.html)). The fielder seems to be making “anticipatory field adjustments” (AFAs?) in anticipation of being in the proper position to catch the ball. But we have found that the fielder’s behavior can be accounted for quite well by a model that involves no prediction at all; the fielder in the ball catching demo gets to the correct position by controlling two present time perceptual variables: vertical and horizontal optical velocity.Â

> >

> > RM: The PCT model I propose to account for the postural adjustments that seem to anticipate future disturbances (APAs) also involves no prediction. My model involves present time control of an event perception that I call “reach”; I didn’t define it very well because I don’t have a good idea of what it is but this event would be a _temporal pattern_ of proprioceptive sensations – sensed angles of the limbs, center of gravity, etc. This temporal pattern is a perceptual variable, just as a temporal pattern of phonemes is a perceptual variable. The “reach” control system I proposed uses variations in posture (including APAs), limb angles and muscle forces to bring this perceptual variable to the reference state (that I called “reach”) while protecting it from disturbances that can affect the perception at any point during its production. I’m conceiving this control as being analogous to controlling for saying a particular word, as described in the “Control of Sequence” chapter of B:CP. In that model of word production there is also no prediction involved; the perceptual function just “constructs” a word based on the sequence of phonemes (analogous to the postural adjustments occurring during a “reach”) that are produced by lower level systems. It doesn’t predict what phoneme is coming next.

> >

> > RM: In order to test this model we really have to come up with a clearer definition of the proposed controlled variable – which I suppose could be called “reachness”. And it really would be good to have a working model of this behavior, if for no other reason than to show how a model that controls a variable that is _defined over time_ can be controlled. I believe that the most important way that PCT differs from other control models of the behavior of living systems is that it assumes that ALL behavior is control; And since control always involves the control of perception that means that simple behaviors involve the control of simple perceptions and complex behaviors involve the control of complex perceptions – and these are usually perceptions that are defined over sometimes considerable amounts of time. This is one of the main reasons why Bill proposed a hierarchy of perceptions. It was to account for the obviously hierarchical nature of behavior – behaviors “using” other behaviors to achieve their purposes; for example, using behaviors like running, throwing, catching and hitting to achieve the purpose of playing baseball – and for the fact that the behaviors that use other behaviors to achieve their purposes involve control of more complex perceptions than the behaviors that are being used;Â the perception controlled when “playing baseball” is much more complex (and defined over a much longer time period) than the perceptions controlled when running, throwing, catching and hitting.

> >

> > > HB-B: We know that both humans and cats fail to show APAs if they are taken by surprise.Â

> >

> > RM: Yes, I noticed that. From the perspective of my model, that would result from not setting the reference for “reach” or " bilateral arm movement" or whatever the event is. This happens a lot in my sport, racquetball. The ideal way to take a forehand shot is to do a lot of APAs that get you into position to take it off the back wall. But sometimes I get a shot that comes at me so fast that I don’t have time to set up for a “proper forehand shot” – no APAs needed – so I just do what I can to move the racket to the ball like a beginner. Â

> >

> > RM: I hope this makes some sense because I think it would really be a great area for research on control of higher level perceptual variables – variables that are defined over time.Â

> >

> > Best

> >

> > Rick

> >

> > > So yes, some environmental information serves to remove the surprise, kicking the control systems into gear. Is that (those) control system(s), dealing with the appearance of the target often used in the cat experiments to signal the upcoming stimulus, totally divorced from the “paw bat” ones? Should they be coupled? What happens if the expected stimulus never arrives, but the target remains? I guess there is fatigue at some point. What is the relevant question to ask?

> > >

> > > In populations of upper motor neurons in motor and premotor cortex, there is often activity seconds before any movement is observed. What does that mean for control systems? That’s obviously not just delay. Those populations get input from… like everwhere. Motor cortex is bonkers! Â

> > >

> > >

> > >

> > > > [Rick Marken 2019-05-10\_11:53:31]

> > > >

> > > > RM: Well, this has certainly been an interesting thread so far. I’m happy to see that there is a kind of consensus that the PCT explanation of apparent “anticipatory” behavior is that it is likely to be actions aimed at controlling a “higher level” controlled variable. The landslide was started by Henry Yin who said:
> > > > 
> > > > > HY: There’s no conflict between negative feedback and anticipatory behavior. The real question is what kind of CV do you need to produce such behavior.
> > > > 
> > > > RM: I think this is the right question: what kind of CV would an organism be controlling that would result in your seeing such apparently "anticipatory"Â behavior. Martin suggests that the CV is a sequence:
> > > > 
> > > > > MT: [Here is a] quick and dirty PCT approach. I start with the intention to bat at the target, which would set a reference for a sequence that could crudely be taken as “store energy, set trigger, wait, release energy when required”, or in a more general sense “Prepare, wait, execute”.

> > > > RM: And Erling agrees:
> > > > 
> > > > > EJ: Â I rather like Martin’s proposal for controlling a prior stage in a sequence. Â
> > > > 
> > > > RM: And I agree that the CV is something like a sequence, but not like the one Martin suggests. In the case of the an anticipatory postural adjustments (APAs) seen in the cat’s reaching behavior (described in the Sheppen and Drew paper), it seems to me that the controlled variable is the “reach” itself – an event – like a “golf swing”. An event differs from a sequence only inasmuch as it is a continuously changing sequence of lower level perceptions that is defined over time. The “reach” requires making postural changes over time that get the paw to the intended destination while maintaining balance. So I see the APAs as the initial components of this “reach” event.Â

> > > >

> > > > RM: I see these APA’s as being analogous to the initial muscular movements – for example, contraction of the diaphragm - that are involved in producing a word. These movements are not outputs produced in anticipation of a future disturbance but are the outputs in a control loop that is aimed at controlling a perception of the word. The word itself, like reach, is the controlled variable – a variable that is defined over time.Â

> > > >

> > > > RM: Because “reach” is defined over time it looks like the initial postural adjustments that are made to control this perception are anticipatory. But I believe that they are actually just like the outputs in any control loop – continuously acting to keep the controlled variable in a reference state, protected from disturbances. If this is the case – if APAs are actually the initial outputs of a control loop controlling a variable that is defied over time – then disturbances to these APA’s will be resisted. Heather mentions some data that is consistent with this view:
> > > > 
> > > > > NB-B: I suspect that the attached (Aruin, 2003) paper goes some way toward reconciling the “invariant, pre-programmed” feedforward conceptualization with the actual phenomenon: namely, it’s not really invariant (or, well, it’s not invariant in that there is a pre-programmed set of muscles activated in a pre-programmed way). Â

> > > > RM: I haven’t read the whole article carefully but apparently what Arium did was look to see whether variations in the initial the position of the body affected the nature of the APAs. And indeed it did. I see these variations in the initial position of the body as disturbances to a controlled variable (in Arium’s case it was “bilateral arm movement” rather than “reach”) and these disturbances are compensated for by the variations in the APAs.Â

> > > >

> > > > RM: Of course, the idea that APAs are the outputs in a control loop controlling a variable defined over time has to be subjected to far more tests. And control models should be built to show that control of a higher level perception, like “reach”, can lead to behavior that “looks” anticipatory. So there’s some general ideas for PCT research that would be a great place to start for researchers interested in doing research on purpose!

> > > >

> > > > BestÂ

> > > >

> > > > Rick

> > > > Â

> > > >

> > > >

> > > >

> > > > –  
> > > > Richard S. MarkenÂ

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

> >

> > –  
> > Richard S. MarkenÂ

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

> **···**
>
> > On Fri, May 10, 2019, 17:05 Richard Marken [csgnet@lists.illinois.edu](mailto:csgnet@lists.illinois.edu) wrote:
> > 
> > > On Fri, May 10, 2019 at 12:50 PM Heather Broccard-Bell [random.information.consultant@gmail.com](mailto:random.information.consultant@gmail.com) wrote:
> > > 
> > > > On Fri, May 10, 2019, 11:59 Richard Marken [csgnet@lists.illinois.edu](mailto:csgnet@lists.illinois.edu) wrote:

---

<div class="post-metadata">

**Author:** ![rsmarken](http://discourse.iapct.org/user_avatar/discourse.iapct.org/rsmarken/32/3553_2.png) [@rsmarken](http://discourse.iapct.org/u/rsmarken)\
**Post date:** [May 11, 2019, 6:59pm UTC](http://discourse.iapct.org/t/anticipatory-postural-control/1164/33 "2019-05-11T18:59:20Z")

</div>

[Rick Marken 2019-05-11\_11:58:37]

> HB-B: I think this does make sense, and would be interesting to build. I am curious about a ‘critical experiment’ that would distinguish the PCT model from the mainstream account… although it does seem to be one of these phenomena that people have described without couching it in any particular theoretical framework, so this may not be possible.

RM: I think the APA phenomenon is implicitly couched in a particular theoretical framework; that of an open-loop causal model of behavior. The implication is that the APA is an output that is being produced open-loop in anticipation of a future perturbation. This can be tested because my model assumes that APAs are actually controlled variables that are used to control another controlled variable – the event called “reaching”. So applying an appropriately gentle, varying force disturbance to the postural change being made during the period of the APA should be resisted. This resistance should be detectable as appropriate variation in the force exerted by the animal during the APA period – the force used to produce the APA. It should also be detectable as consistency of the APA on different trials with different disturbances; this could be determined by analysis of visual records to see if the variation in the APA over trials is what would be expected based on variatoin in teh disturbances.Â

RM: I think there might be a way to create a “portable demo” of behavior that seems to involve an APA. I’ll see if I can think of one.

BestÂ

Rick

Â

> **···**
>
> On Fri, May 10, 2019 at 8:05 PM Heather Broccard-Bell [random.information.consultant@gmail.com](mailto:random.information.consultant@gmail.com) wrote:
> 
> > On Fri, May 10, 2019, 17:05 Richard Marken [csgnet@lists.illinois.edu](mailto:csgnet@lists.illinois.edu) wrote:
> 
> > > [Rick Marken 2019-05-10\_17:04:34]
> 
> > >
> 
> > > On Fri, May 10, 2019 at 12:50 PM Heather Broccard-Bell [random.information.consultant@gmail.com](mailto:random.information.consultant@gmail.com) wrote:
> 
> > > > HB: I kind of think a lot of the problem is semantic. Some seem to be upset by the term “prediction” or “anticipation”, and I think what Rick/Henry suggest is a reasonable explanation for a _mechanism_ for what most people would call anticipation/prediction. It can’t be magic :))
> 
> > >
> 
> > > RM: The only time I get upset by terms like “prediction” and “anticipation” is when they give the wrong impression of how the PCT model explains some behaviors. This usually happens when it “looks like” a behavior involves “prediction” or “anticipation”.  For example, the behavior called “catching a fly ball” appears to involve “prediction” or “anticipation”. You can see it in the movements of the fielder in my baseball catch simulation ([https://www.mindreadings.com/ControlDemo/CatchXY.html](https://www.mindreadings.com/ControlDemo/CatchXY.html)). The fielder seems to be making “anticipatory field adjustments” (AFAs?) in anticipation of being in the proper position to catch the ball. But we have found that the fielder’s behavior can be accounted for quite well by a model that involves no prediction at all; the fielder in the ball catching demo gets to the correct position by controlling two present time perceptual variables: vertical and horizontal optical velocity.Â
> 
> > >
> 
> > > RM: The PCT model I propose to account for the postural adjustments that seem to anticipate future disturbances (APAs) also involves no prediction. My model involves present time control of an event perception that I call “reach”; I didn’t define it very well because I don’t have a good idea of what it is but this event would be a _temporal pattern_ of proprioceptive sensations – sensed angles of the limbs, center of gravity, etc. This temporal pattern is a perceptual variable, just as a temporal pattern of phonemes is a perceptual variable. The “reach” control system I proposed uses variations in posture (including APAs), limb angles and muscle forces to bring this perceptual variable to the reference state (that I called “reach”) while protecting it from disturbances that can affect the perception at any point during its production. I’m conceiving this control as being analogous to controlling for saying a particular word, as described in the “Control of Sequence” chapter of B:CP. In that model of word production there is also no prediction involved; the perceptual function just “constructs” a word based on the sequence of phonemes (analogous to the postural adjustments occurring during a “reach”) that are produced by lower level systems. It doesn’t predict what phoneme is coming next.
> 
> > >
> 
> > > RM: In order to test this model we really have to come up with a clearer definition of the proposed controlled variable – which I suppose could be called “reachness”. And it really would be good to have a working model of this behavior, if for no other reason than to show how a model that controls a variable that is _defined over time_ can be controlled. I believe that the most important way that PCT differs from other control models of the behavior of living systems is that it assumes that ALL behavior is control; And since control always involves the control of perception that means that simple behaviors involve the control of simple perceptions and complex behaviors involve the control of complex perceptions – and these are usually perceptions that are defined over sometimes considerable amounts of time. This is one of the main reasons why Bill proposed a hierarchy of perceptions. It was to account for the obviously hierarchical nature of behavior – behaviors “using” other behaviors to achieve their purposes; for example, using behaviors like running, throwing, catching and hitting to achieve the purpose of playing baseball – and for the fact that the behaviors that use other behaviors to achieve their purposes involve control of more complex perceptions than the behaviors that are being used;Â the perception controlled when “playing baseball” is much more complex (and defined over a much longer time period) than the perceptions controlled when running, throwing, catching and hitting.
> 
> > >
> 
> > > > HB-B: We know that both humans and cats fail to show APAs if they are taken by surprise.Â
> 
> > >
> 
> > > RM: Yes, I noticed that. From the perspective of my model, that would result from not setting the reference for “reach” or " bilateral arm movement" or whatever the event is. This happens a lot in my sport, racquetball. The ideal way to take a forehand shot is to do a lot of APAs that get you into position to take it off the back wall. But sometimes I get a shot that comes at me so fast that I don’t have time to set up for a “proper forehand shot” – no APAs needed – so I just do what I can to move the racket to the ball like a beginner. Â
> 
> > >
> 
> > > RM: I hope this makes some sense because I think it would really be a great area for research on control of higher level perceptual variables – variables that are defined over time.Â
> 
> > >
> 
> > > Best
> 
> > >
> 
> > > Rick
> 
> > >
> 
> > > > So yes, some environmental information serves to remove the surprise, kicking the control systems into gear. Is that (those) control system(s), dealing with the appearance of the target often used in the cat experiments to signal the upcoming stimulus, totally divorced from the “paw bat” ones? Should they be coupled? What happens if the expected stimulus never arrives, but the target remains? I guess there is fatigue at some point. What is the relevant question to ask?
> 
> > > >
> 
> > > > In populations of upper motor neurons in motor and premotor cortex, there is often activity seconds before any movement is observed. What does that mean for control systems? That’s obviously not just delay. Those populations get input from… like everwhere. Motor cortex is bonkers! Â
> 
> > > >
> 
> > > >
> 
> > > > On Fri, May 10, 2019, 11:59 Richard Marken [csgnet@lists.illinois.edu](mailto:csgnet@lists.illinois.edu) wrote:
> 
> > > > > [Rick Marken 2019-05-10\_11:53:31]
> 
> > > > >
> 
> > > > > RM: Well, this has certainly been an interesting thread so far. I’m happy to see that there is a kind of consensus that the PCT explanation of apparent “anticipatory” behavior is that it is likely to be actions aimed at controlling a “higher level” controlled variable. The landslide was started by Henry Yin who said:
> > > > > 
> > > > > > HY: There’s no conflict between negative feedback and anticipatory behavior. The real question is what kind of CV do you need to produce such behavior.
> > > > > 
> > > > > RM: I think this is the right question: what kind of CV would an organism be controlling that would result in your seeing such apparently "anticipatory"Â behavior. Martin suggests that the CV is a sequence:
> > > > > 
> > > > > > MT: [Here is a] quick and dirty PCT approach. I start with the intention to bat at the target, which would set a reference for a sequence that could crudely be taken as “store energy, set trigger, wait, release energy when required”, or in a more general sense “Prepare, wait, execute”.
> 
> > > > > RM: And Erling agrees:
> > > > > 
> > > > > > EJ: Â I rather like Martin’s proposal for controlling a prior stage in a sequence. Â
> > > > > 
> > > > > RM: And I agree that the CV is something like a sequence, but not like the one Martin suggests. In the case of the an anticipatory postural adjustments (APAs) seen in the cat’s reaching behavior (described in the Sheppen and Drew paper), it seems to me that the controlled variable is the “reach” itself – an event – like a “golf swing”. An event differs from a sequence only inasmuch as it is a continuously changing sequence of lower level perceptions that is defined over time. The “reach” requires making postural changes over time that get the paw to the intended destination while maintaining balance. So I see the APAs as the initial components of this “reach” event.Â
> 
> > > > >
> 
> > > > > RM: I see these APA’s as being analogous to the initial muscular movements – for example, contraction of the diaphragm - that are involved in producing a word. These movements are not outputs produced in anticipation of a future disturbance but are the outputs in a control loop that is aimed at controlling a perception of the word. The word itself, like reach, is the controlled variable – a variable that is defined over time.Â
> 
> > > > >
> 
> > > > > RM: Because “reach” is defined over time it looks like the initial postural adjustments that are made to control this perception are anticipatory. But I believe that they are actually just like the outputs in any control loop – continuously acting to keep the controlled variable in a reference state, protected from disturbances. If this is the case – if APAs are actually the initial outputs of a control loop controlling a variable that is defied over time – then disturbances to these APA’s will be resisted. Heather mentions some data that is consistent with this view:
> > > > > 
> > > > > > NB-B: I suspect that the attached (Aruin, 2003) paper goes some way toward reconciling the “invariant, pre-programmed” feedforward conceptualization with the actual phenomenon: namely, it’s not really invariant (or, well, it’s not invariant in that there is a pre-programmed set of muscles activated in a pre-programmed way). Â
> 
> > > > > RM: I haven’t read the whole article carefully but apparently what Arium did was look to see whether variations in the initial the position of the body affected the nature of the APAs. And indeed it did. I see these variations in the initial position of the body as disturbances to a controlled variable (in Arium’s case it was “bilateral arm movement” rather than “reach”) and these disturbances are compensated for by the variations in the APAs.Â
> 
> > > > >
> 
> > > > > RM: Of course, the idea that APAs are the outputs in a control loop controlling a variable defined over time has to be subjected to far more tests. And control models should be built to show that control of a higher level perception, like “reach”, can lead to behavior that “looks” anticipatory. So there’s some general ideas for PCT research that would be a great place to start for researchers interested in doing research on purpose!
> 
> > > > >
> 
> > > > > BestÂ
> 
> > > > >
> 
> > > > > Rick
> 
> > > > > Â
> 
> > > > >
> 
> > > > >
> 
> > > > >
> 
> > > > > –  
> > > > > Richard S. MarkenÂ
> 
> > > > > "Perfection is achieved not when you have nothing more to add, but when you  
> > > > > have nothing left to take away.�  
> > > > > Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â --Antoine de Saint-Exupery
> 
> > >
> 
> > > –  
> > > Richard S. MarkenÂ
> 
> > > "Perfection is achieved not when you have nothing more to add, but when you  
> > > have nothing left to take away.�  
> > > Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â --Antoine de Saint-Exupery
> 
> –  
> Richard S. MarkenÂ
> 
> "Perfection is achieved not when you have nothing more to add, but when you  
> have nothing left to take away.�  
> Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â --Antoine de Saint-Exupery

---

<div class="post-metadata">

**Author:** ![rsmarken](http://discourse.iapct.org/user_avatar/discourse.iapct.org/rsmarken/32/3553_2.png) [@rsmarken](http://discourse.iapct.org/u/rsmarken)\
**Post date:** [May 11, 2019, 11:29pm UTC](http://discourse.iapct.org/t/anticipatory-postural-control/1164/34 "2019-05-11T23:29:03Z")

</div>

[Rick Marken 2019-05-11\_16:26:30]

> [Mike Acree 2019.05.11.12.53 PST]

> MA: The “anticipatory pretension,â€? or whatever, is what presumably  
> prevents us from tickling ourselves as effectively as another person can.

RM: I thought it was just growing old that did it;-)

Â

>  MA: The phenomenon also makes me think of the “cortical readiness  
> wave� discovered by the British neurophysiologist Grey Walter about 60 years  
> ago—a potential preceding any voluntary motor act by a few millisecconds.  
> He had people viewing a sequence of slides, advancing them by pressing a  
> button; but when he wired the projector to be operated by the cortical  
> readiness wave, all they had to do was “get readyâ€? for the next slide to  
> appear—to “willâ€? it into existence, as it wereâ—and there it was. The  
> experience was so unnerving that several people wet their pants.

RM: What a great story! With bluetooth maybe this would be the way to make it so that I don’t have to press all those damn buttons on my remote.Â

RM: This sounds like the electrical effects of a change in reference rather than an anticipatory adjustment in anticipation of a future disturbance. It is a real phenomenon, though, And since it seems like it corresponds to the setting of an intention (to press a button, say) it would correspond to a reference signal change in PCT. But why would a change in one little reference signal (for a minor motor action) show up in a rather gross measure of electrical activity is somewhat surprising to me. But I suppose if you are just sitting waiting to indicate that you are ready to see a picture, there aren’t many other reference signals changing.Â

BestÂ

Rick

> **···**
>
> Richard S. MarkenÂ
> 
> "Perfection is achieved not when you have nothing more to add, but when you  
> have nothing left to take away.�  
> Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â --Antoine de Saint-Exupery

---

<div class="post-metadata">

**Author:** ![\_Boris\_Hartman](http://discourse.iapct.org/letter_avatar_proxy/v4/letter/_/e8c25b/32.png) [@\_Boris\_Hartman](http://discourse.iapct.org/u/_Boris_Hartman)\
**Post date:** [May 12, 2019, 4:59am UTC](http://discourse.iapct.org/t/anticipatory-postural-control/1164/35 "2019-05-12T04:59:28Z")

</div>

Rick,

> **···**
>
> **From:** Richard Marken ([rsmarken@gmail.com](mailto:rsmarken@gmail.com) via csgnet Mailing List) [csgnet@lists.illinois.edu](mailto:csgnet@lists.illinois.edu)  
> **Sent:** Thursday, May 9, 2019 3:01 AM  
> **To:** csgnet [csgnet@lists.illinois.edu](mailto:csgnet@lists.illinois.edu); Henry Yin [hy43@duke.edu](mailto:hy43@duke.edu)  
> **Cc:** Richard Marken [rsmarken@gmail.com](mailto:rsmarken@gmail.com)  
> **Subject:** Anticipatory Postural Control
> 
> [Rick Marken 2019-05-08\_17:57:30]
> 
> RM: Some time ago Heather Broccard-Bell asked me what the PCT explanation might be of a behavior that looks like a pretty robust example of anticipatory (or feedforward) control. Here’s how Heather described it to me:
> 
> > HB-B: I was reading about this finding (and perhaps you are already familiar) that, if if you measure muscle activation during behavior, you often see compensatory activation of the axial musculature well before you get activation in the muscles that direct the part of the body that does the thing you’re focused on. For example, they trained cats to bat at a target with their forepaw. \*\*Well before the limb/forepaw muscles are active, there is activation in the trunk musculature, seemingly anticipating the requisite compensatory stabilization that will become necessary when the forepaw is lifted. \*\* I am wondering what a PCT perspective might be on that? What is the relevant controlled variable, since the thing that actually changes sensory input that should activate control architecture hasn’t yet happened? Am I missing something? It appears to be a rather robust finding.[emphasis mine–RM]
> 
> RM: This finding certainly looks like it is inconsistent with the predictions of PCT
> 
> HB : I just can’t beleive that you are trying to prove that PCT is wrong theory and RCT is right theory.
> 
> RM : …since it looks like the cat is generating an output (activation of the trunk musculature) open loop in anticipation of a future disturbance (the change in orientation of the body when the forepaw is lifted, a change in orientation that would cause the cat to lose its balance if the trunk were not in the proper position).
> 
> HB : You have first to understand PCT to judge whether something is in accordance to PCT or not. And many times we saw that you don’t understand PCT. But you understand RCT ; So first you’ll have to change something about your theorethical approach. After few years you made some changes at least you supplement your wrong RCT theory with more wrong RCT theory.
> 
> RM : And here is my corrected version:
> 
> 1. CONTROL : Keeping of some aspect of outer environment – the controlled variable – in a reference state, protected from disturbances.
> 
> 2. OUTPUT FUNCTION : Function that converts an error signal into an output variable that has effects in the environment.
> 
> 3. FEED-BACK FUNCTION : Physical laws that determine effect of system outputs on a controlled variable.
> 
> 4. INPUT FUNCTION : Function that converts sensory or perceptual inputs into a perceptual signal that is an analog of the aspect of the environment – the controlled variable – defined by the nature of this function.
> 
> 5. COMPARATOR : Function that takes a perceptual and a reference signal as input and produces an error signal as output, the error signal being proportional to the difference between the inputs to this function.
> 
> 6. ERROR SIGNAL : The output of the comparator function.
> 
> 7. CONTROLLED VARIABLE (or CONTROLLED QUANTITY): The aspect of the environment, defined by the input function, that is controlled by a control system.
> 
> HB : If you want to get clear about PCT and RCT you’ll need more experiments specially such which will clearly show how “behavior works”.
> 
> RM: Apparently, quite a lot of research has been (and is still being) done on this “anticipatory postural control” phenomenon. Here is a paper by Aruin and Latash that Heather sent on the finding of “anticipatory postural control” when people drop a weight:
> 
> [https://www.dropbox.com/s/hat2ua3ah7rqs79/aruin1995.pdf?dl=0](https://urldefense.proofpoint.com/v2/url?u=https-3A__www.dropbox.com_s_hat2ua3ah7rqs79_aruin1995.pdf-3Fdl-3D0&d=DwMFAg&c=OCIEmEwdEq_aNlsP4fF3gFqSN-E3mlr2t9JcDdfOZag&r=G2rjwc9SjlT6Blyc8su_Md8P_xOsOTRMJ5teQVBC2qU&m=0lpxyl-5vAzUhxPSgW-nSPORMzI8BMqU4tf_k-X072E&s=wtf5Dl4giWujrHmkd_B3WidUvotV2-KbU1Bk6d_bPM0&e=)
> 
> HB : It can help, but core experiments should be such that clear data will show whether PCT or RCT is right or both are wrong.
> 
> RM: Here there is again clear evidence that the person takes compensatory action (contracts muscles) in anticipation of a future disturbance that would cause a loss of balance if the anticipatory compensation had not occurred.
> 
> HB : “Anticipatory compensation” is not PCT term. But if you’ll change terminology into PCT you might get PCT explanation. As far as I know “posture control” is good example of pure “Control of perception”. No “Control of behavior”. From Pathothysiological view it seems that at least 2 perceptions have to be controlled so that LCS can be relativelly stable in garvitational field. And “Control of perception” could use some higher level references to make “feed-forward compensation” to disturbances to posture. Maybe Bill didn’t mention specifically how these meachanisms are present in organism, but I’m sure they can be explained with PCT hierarchy as Heather pointed out :
> 
> HB-B : …really the only way you could get that to work is hierarchical control with continuous feedback…
> 
> HB : So your conclussion about PCT seems to be wrong.
> 
> RM earlier : This finding certainly looks like it is inconsistent with the predictions of PCT…
> 
> HB : You seem that you are catching at a straw traying to prove that PCT is wrong theory and RCT is right. As I emphasized many times before, first you should understand PCT before you give any oppinion about PCT.
> 
> RM: Heather also described this related neurophysiological observation:
> 
> > HB-B: \*\*Related, it was discovered that if you knock out the indirect pathway from motor cortex to spinal cord (through the reticular formation), but leave the direct pathway intact, you abolish the “prestabilizing”, but still get the paw bat. \*\* I think you could explain that, in a super-oversimplified way, in terms of those pathways being about different control systems (these bastards have ascending, descending, and reciprocal connections at every level, not to mention all kinds of built-in sensory elements and sensory inputs connecting from elsewhere, as any good ultracomplex biological control system would).
> 
> RM: I am posting this to you experts on PCT (with Heather’s permission) because I think this is a very interesting discovery that seems to pose a challenge to PCT and I would like to see what you think about this. I have an idea about how PCT would explain this “anticipatory postural control” phenomenon and I think the Aruin  
> and Latash paper pointed to above suggests a way to test it. But before I give my PCT explanation I’d like to see what you think.
> 
> HB : Well if you want to give RCT explanation of PCT than you rather wait before you understand PCT. But if you’ll start with non “tracking” experiments to prove which theory is right than something can happen. You need at least 10 to 20 PCT experiments. You know if you have PhD how scientific work should be done.
> 
> 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

---

<div class="post-metadata">

**Author:** ![\_Boris\_Hartman](http://discourse.iapct.org/letter_avatar_proxy/v4/letter/_/e8c25b/32.png) [@\_Boris\_Hartman](http://discourse.iapct.org/u/_Boris_Hartman)\
**Post date:** [May 12, 2019, 4:59am UTC](http://discourse.iapct.org/t/anticipatory-postural-control/1164/36 "2019-05-12T04:59:32Z")

</div>

Hi Heather

> **···**
>
> **From:** Heather Broccard-Bell (hebell@ucsd.edu via csgnet Mailing List) [csgnet@lists.illinois.edu](mailto:csgnet@lists.illinois.edu)  
> **Sent:** Thursday, May 9, 2019 3:28 PM  
> **To:** csgnet@lists.illinois.edu; Martin Taylor [mmt@mmtaylor.net](mailto:mmt@mmtaylor.net); Henry Yin [hy43@duke.edu](mailto:hy43@duke.edu)  
> **Subject:** Anticipatory Postural Control
> 
> I suspect that the attached (Aruin, 2003) paper goes some way toward reconciling the “invariant, pre-programmed” feedforward conceptualization with the actual phenomenon: namely, it’s not really invariant (or, well, it’s not invariant in that there is a pre-programmed set of muscles activated in a pre-programmed way). So, I suspect that some of the problem in the “mainstream” is semantic.
> 
> Anyway, long (~500 ms) stimulation of motor cortex has already demonstrated that “motor output” seems to be about goals, and not specific, muscle-by-muscle motor programs (see Graziano, 2002; attached), and really the only way you could get that to work is hierarchical control with continuous feedback…
> 
> HB : I agree.
> 
> Boris
> 
> On Wed, May 8, 2019, 21:16 Martin Taylor [csgnet@lists.illinois.edu](mailto:csgnet@lists.illinois.edu) wrote:
> 
> > [Martin Taylor 2019.05.09.00.09]
> 
> > > [Rick Marken 2019-05-08\_17:57:30]
> 
> > > RM: Some time ago Heather Broccard-Bell asked me what the PCT explanation might be of a behavior that looks like a pretty robust example of anticipatory (or feedforward) control. Here’s how Heather described it to me:
> 
> > > > HB-B: I was reading about this finding (and perhaps you are already familiar) that, if if you measure muscle activation during behavior, you often see compensatory activation of the axial musculature well before you get activation in the muscles that direct the part of the body that does the thing you’re focused on. For example, they trained cats to bat at a target with their forepaw. \*\*Well before the limb/forepaw muscles are active, there is activation in the trunk musculature, seemingly anticipating the requisite compensatory stabilization that will become necessary when the forepaw is lifted. \*\* I am wondering what a PCT perspective might be on that? What is the relevant controlled variable, since the thing that actually changes sensory input that should activate control architecture hasn’t yet happened? Am I missing something? It appears to be a rather robust finding.[emphasis mine–RM]
> 
> > > …
> 
> > > RM: I am posting this to you experts on PCT (with Heather’s permission) because I think this is a very interesting discovery that seems to pose a challenge to PCT and I would like to see what you think about this.
> 
> > Here is section of what I wrote to Heather on this question April 12.
> > 
> > * * *
> > 
> > [Here is a] quick and dirty PCT approach. I start with the intention to bat at the target, which would set a reference for a sequence that could crudely be taken as “store energy, set trigger, wait, release energy when required”, or in a more general sense “Prepare, wait, execute”. You call the storage “prestabilizing”, but I think Powers would have called that a “dormitive principle” that just labels what happens without in any way explaining how or why. The “stabilizing” is postural control of the normal kind, the same as would happen if you pushed the cat. If you have seen a video of the “Big Dog” robot, you have seen this kind of stabilization.
> > 
> > The magician Harry Houdini died because he hadn’t stored the energy to resist a blow to his abdomen when someone hit him before he was prepared, which he did by tensing (supplying energy to) the stomach muscles. He had offered a general challenge that nobody could hit him there hard enough to hurt him, but the hitter was supposed to do it in a formal kind of way, when he was prepared. When the fatal blow was struck, his muscles had insufficient stored energy to oppose the shock energy in the blow.
> > 
> > I think the actual stabilization is simply the use of some of the pre-tensioned stored energy in normal postural control against a force that would be destabilizing, but instead of the control being entirely to oppose a sensed disturbance, it is part of the output side support of the sequence controller. The “bat” is not simply sending reference values to muscles that move the paw relative to the torso, it is sending reference values to all the postural muscles in a temporal pattern that has been reorganized into the control hierarchy in the same way as a trained athlete such as a ballerina coordinates the timings and strengths of her muscle movements so that what an observer calls “the” action doesn’t interfere with her balance.
> > 
> > Anyway, those are my first thoughts on the question, before breakfast.
> > 
> > * * *
> > 
> > I haven’t considered the problem since then, but I thought I might offer the suggestion.
> > 
> > The saying “Reculer pour mieux sauter” seems to be about the same phenomenon.
> > 
> > Martin

---

<div class="post-metadata">

**Author:** ![\_Boris\_Hartman](http://discourse.iapct.org/letter_avatar_proxy/v4/letter/_/e8c25b/32.png) [@\_Boris\_Hartman](http://discourse.iapct.org/u/_Boris_Hartman)\
**Post date:** [May 12, 2019, 5:01am UTC](http://discourse.iapct.org/t/anticipatory-postural-control/1164/37 "2019-05-12T05:01:38Z")

</div>

Rick

> **···**
>
> **From:** Richard Marken ([rsmarken@gmail.com](mailto:rsmarken@gmail.com) via csgnet Mailing List) [csgnet@lists.illinois.edu](mailto:csgnet@lists.illinois.edu)  
> **Sent:** Friday, May 10, 2019 8:59 PM  
> **To:** csgnet [csgnet@lists.illinois.edu](mailto:csgnet@lists.illinois.edu)  
> **Cc:** Henry Yin [hy43@duke.edu](mailto:hy43@duke.edu)  
> **Subject:** Re: Anticipatory Postural Control
> 
> [Rick Marken 2019-05-10\_11:53:31]
> 
> RM: Well, this has certainly been an interesting thread so far. I’m happy to see that there is a kind of consensus that the PCT explanation of apparent “anticipatory” behavior is that it is likely to be actions aimed at controlling a “higher level” controlled variable. The landslide was started by Henry Yin who said:
> 
> > HY: There’s no conflict between negative feedback and anticipatory behavior. The real question is what kind of CV do you need to produce such behavior.
> 
> HB : Well at least on thing we all agree.
> 
> RM: I think this is the right question: what kind of CV would an organism be controlling that would result in your seeing such apparently “anticipatory” behavior. Martin suggests that the CV is a sequence:
> 
> > MT: [Here is a] quick and dirty PCT approach. I start with the intention to bat at the target, which would set a reference for a sequence that could crudely be taken as “store energy, set trigger, wait, release energy when required”, or in a more general sense “Prepare, wait, execute”.
> 
> RM: And Erling agrees:
> 
> > EJ: I rather like Martin’s proposal for controlling a prior stage in a sequence.
> 
> HB : I think it’s not about what kind of CV is controlled ? I think it’s about mechanism of hierarchical “Control of perception” that enable better control. By my oppinon mechanism is general and developed through evolution. But who cares what I think 😊
> 
> RM: And I agree that the CV is something like a sequence, but not like the one Martin suggests.
> 
> HB : Well as far as I read Martins thoughts they make more sense than your suggestions. Maybe some terms could be adapted. Â
> 
> RM : In the case of the an anticipatory postural adjustments (APAs) seen in the cat’s reaching behavior (described in the Sheppen and Drew paper), it seems to me that the controlled variable is the “reach” itself – an event – like a “golf swing”.
> 
> HB : It just seems to you, because you want to see it that way . Even observing has it’s purpose. Every behavior has it’s purpose. People are not just moving their limbs becuase of moving their limbs. Even “golf swing” has it’s higher level purpose.
> 
> RM : An event differs from a sequence only inasmuch as it is a continuously changing sequence of lower level perceptions that is defined over time.
> 
> HB : And of course “sequence level” has it’s higher levels.
> 
> RM : The “reach” requires making postural changes over time that get the paw to the intended destination while maintaining balance. So I see the APAs as the initial components of this “reach” event.
> 
> HB : What is maintaining balance ? Could be “Control of perception” ?
> 
> RM: I see these APA’s as being analogous to the initial muscular movements – for example, contraction of the diaphragm - that are involved in producing a word. These movements are not outputs produced in anticipation of a future disturbance but are the outputs in a control loop that is aimed at controlling a perception of the word. The word itself, like reach, is the controlled variable – a variable that is defined over time.
> 
> HB : Controlled variable that is defined over time ? What is CV here ?
> 
> RM: Because “reach” is defined over time it looks like the initial postural adjustments that are made to control this perception are anticipatory. But I believe that they are actually just like the outputs in any control loop – continuously acting to keep the controlled variable in a reference state, protected from disturbances.
> 
> HB : Rick. I didn’t want to interfear until you started again with your RCT and “controlled variable” kept in reference state “protected from disturbances”. I thought this is past “nightmare”. But it seems that you’ll never stop pushing with newer version of RCT.
> 
> RM : And here is my corrected version:
> 
> 1. CONTROL : Keeping of some aspect of outer environment – the controlled variable – in a reference state, protected from disturbances.
> 
> 2. OUTPUT FUNCTION : Function that converts an error signal into an output variable that has effects in the environment.
> 
> 3. FEED-BACK FUNCTION : Physical laws that determine effect of system outputs on a controlled variable.
> 
> 4. INPUT FUNCTION : Function that converts sensory or perceptual inputs into a perceptual signal that is an analog of the aspect of the environment – the controlled variable – defined by the nature of this function.
> 
> 5. COMPARATOR : Function that takes a perceptual and a reference signal as input and produces an error signal as output, the error signal being proportional to the difference between the inputs to this function.
> 
> 6. ERROR SIGNAL : The output of the comparator function.
> 
> 7. CONTROLLED VARIABLE (or CONTROLLED QUANTITY): The aspect of the environment, defined by the input function, that is controlled by a control system.
> 
> HB : Your theory is wrong and PCT theory is right. You are not continuously “controlling behavior” to keep some CV in reference state, protected from disturbances.
> 
> RM : If this is the case – if APAs are actually the initial outputs of a control loop controlling a variable that is defied over time – then disturbances to these APA’s will be resisted. Heather mentions some data that is consistent with this view:
> 
> > NB-B: I suspect that the attached (Aruin, 2003) paper goes some way toward reconciling the “invariant, pre-programmed” feedforward conceptualization with the actual phenomenon: namely, it’s not really invariant (or, well, it’s not invariant in that there is a pre-programmed set of muscles activated in a pre-programmed way).
> 
> HB : I doubt that “anticipation” or “feed-forward” has something to do with “pre-programmed” set of muscles. Even Heather does not agree if I understood her right.
> 
> HB-B : Anyway, long (~500 ms) stimulation of motor cortex has already demonstrated that “motor output” seems to be about goals, and not specific, muscle-by-muscle motor programs (see Graziano, 2002; attached), and really the only way you could get that to work is hierarchical control with continuous feedback…
> 
> RM: I haven’t read the whole article carefully but apparently what Arium did was look to see whether variations in the initial the position of the body affected the nature of the APAs. And indeed it did. I see these variations in the initial position of the body as disturbances to a controlled variable (in Arium’s case it was “bilateral arm movement” rather than “reach”) and these disturbances are compensated for by the variations in the APAs.
> 
> RM: Of course, the idea that APAs are the outputs in a control loop controlling a variable defined over time has to be subjected to far more tests. And control models should be built to show that control of a higher level perception, like “reach”, can lead to behavior that “looks” anticipatory. So there’s some general ideas for PCT research that would be a great place to start for researchers interested in doing research on purpose!
> 
> HB : Why don’t you start doing tests and experiments as part of PCT research as I suggested you ??? You are just talking and phylosophing all the time and confuse all arround. Martin was doing very fine and I think quite in accordance to PCT although he used different terminology. So I would really advise him to change CEV into CEP. I finaly started to understand what he meant by RREV, CV and CEV. And it’s by my oppinion quite in accordance to PCT. But nothing is so good that can’t be better.
> 
> Although Martin changed his mind couple times what maybe caused some confussion I think that he is on good way explaining how organsims function. Who does not change his mind if “New Theory” is born. Even Bill Powers did it some times.
> 
> Why Rick do you have to crash everything just to prove your nonsense RCT.
> 
> 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

---

<div class="post-metadata">

**Author:** ![\_Boris\_Hartman](http://discourse.iapct.org/letter_avatar_proxy/v4/letter/_/e8c25b/32.png) [@\_Boris\_Hartman](http://discourse.iapct.org/u/_Boris_Hartman)\
**Post date:** [May 12, 2019, 5:04am UTC](http://discourse.iapct.org/t/anticipatory-postural-control/1164/38 "2019-05-12T05:04:23Z")

</div>

Rick

![image002109.jpg](http://discourse.iapct.org/uploads/default/original/1X/d0c828c0981f50f8c54499d8d0ea0a9eee2b36dc.jpeg)

> **···**
>
> **From:** Richard Marken ([rsmarken@gmail.com](mailto:rsmarken@gmail.com) via csgnet Mailing List) [csgnet@lists.illinois.edu](mailto:csgnet@lists.illinois.edu)  
> **Sent:** Saturday, May 11, 2019 2:05 AM  
> **To:** csgnet [csgnet@lists.illinois.edu](mailto:csgnet@lists.illinois.edu)  
> **Cc:** Henry Yin [hy43@duke.edu](mailto:hy43@duke.edu)  
> **Subject:** Re: Anticipatory Postural Control
> 
> [Rick Marken 2019-05-10\_17:04:34]
> 
> On Fri, May 10, 2019 at 12:50 PM Heather Broccard-Bell [random.information.consultant@gmail.com](mailto:random.information.consultant@gmail.com) wrote:
> 
> > HB-B: I kind of think a lot of the problem is semantic. Some seem to be upset by the term “prediction” or “anticipation”, and I think what Rick/Henry suggest is a reasonable explanation for a _mechanism_ for what most people would call anticipation/prediction. It can’t be magic :))
> 
> RM: The only time I get upset by terms like “prediction” and “anticipation” is when they give the wrong impression of how the PCT model explains some behaviors.
> 
> HB : And how PCT explains behavior ??? In PCT or RCT way.
> 
> RM : This usually happens when it “looks like” a behavior involves “prediction” or “anticipation”.
> 
> HB : You don’t know nothing about which meachanism in orgsnism could be responsable for “prediction” (anticipation) and you are judging what PCT explains ?
> 
> RM : For example, the behavior called “catching a fly ball” appears to involve “prediction” or “anticipation”.
> 
> HB : It does involve prediction. Catchers goal is to catch the ball and so he has to “predict” where the ball will fall. If you would collect the data and Bill Poers expected you to do and if you would do some experiments on your own you would see what is happening when somebody tries to “catch the ball”.
> 
> FN earlier :
> 
> The relative movement between me (one the run) and the ball (on the fly) tell me if I’m likely to intercept it or not. If so, I keep doing what I’m doing. If not, I speed up, change course, slow down or whatever it takes to maintain my sense that I am likely to intercept the ball…I think the fielder/catcher is predicting whether or not he can intercept the ball…
> 
> HB : Fred was baseball player if I understood him right. So here we have finally some experiences from the game so that we’ll not guess what is happening and phylosophing what is happening in baseball game. If you want to “intercept” the ball you have to “predict” or anticipate the “intercepting point”. That’s the goal : to catch the ball not to calculate x and dimension of the flight of the ball. And that’s exactly where “fielders” are moving if you’ll look videos about baseball game. To the “catching point”.
> 
> RM : You can see it in the movements of the fielder in my baseball catch simulation ([https://www.mindreadings.com/ControlDemo/CatchXY.html](https://urldefense.proofpoint.com/v2/url?u=https-3A__www.mindreadings.com_ControlDemo_CatchXY.html&d=DwMFAg&c=OCIEmEwdEq_aNlsP4fF3gFqSN-E3mlr2t9JcDdfOZag&r=G2rjwc9SjlT6Blyc8su_Md8P_xOsOTRMJ5teQVBC2qU&m=k4VWC5rO1GMg1fY7rJozrVq9lZhlzmmvbY_i3bQs5Iw&s=S-msYLWrtPwGVjnpTv0tiYopVEFRopRBTVurAviPERY&e=)). The fielder seems to be making “anticipatory field adjustments” (AFAs?) in anticipation of being in the proper position to catch the ball. But we have found that the fielder’s behavior can be accounted for quite well by a model that involves no prediction at all;
> 
> HB : In every movement prediction is involved. Reference is some kind of “prediction” of future state. The question is how succesfull you are in achieving that future state,
> 
> RM : …the fielder in the ball catching demo gets to the correct position by controlling two present time perceptual variables: vertical and horizontal optical velocity.
> 
> HB : They can because they are using “prediction” from those perceptual variables. Your baseball catch is nonsense, and I proved it many times even with videos. Beside that you didn’t show any evidence that you are right, and Bill Powers was dissapointed about that you didn’t collect any data, it seems that you claim that fielders moving (behavior) is not goal directed, but it is “governed” by input from “what ever horizontal and vertical or x and y dimensional movement of the ball” and other nonsense. How can you analyse Life events in “two dimensional space” ?
> 
> RM: The PCT model I propose to account for the postural adjustments that seem to anticipate future disturbances (APAs) also involves no prediction.
> 
> HB : Your “anticipation”, prediction" about PCT is wrong. Bill did change his mind couple times about whatever you want to say about “prediction” but as I said before “prediction” is part of the control hierarchy. The problem seems to be that you don’t understand how it works ?
> 
> RM : My model involves present time control of an event perception that I call “reach”;
> 
> HB : We established for more than 50x that your RCT model of “Control of behavior” which controls some “controlled variable” in environment is wrong.
> 
> RM : I didn’t define it very well because I don’t have a good idea of what it is but this event would be a _temporal pattern_ of proprioceptive sensations – sensed angles of the limbs, center of gravity, etc.
> 
> HB : What kind of terms are these in the light of “Control of Perception”. What is center of gravity ??? How do you sense angles of the limbs ?
> 
> RM : This temporal pattern is a perceptual variable, just as a temporal pattern of phonemes is a perceptual variable. The “reach” control system I proposed
> 
> HB : Where did you proposed “reach” control system ??? Is it RCT or PCT proposal ???
> 
> RM : …uses variations in posture (including APAs), limb angles and muscle forces to bring this perceptual variable to the reference state (that I called “reach”) while protecting it from disturbances
> 
> HB : What exactly here is “protected from disturbances” ? And muscle forces are not “bringing” or “pushing” perceptual variable to the reference state. What does it mean “bringing” ? It seems that you are saying that you directly “control output” or muscle forces to “bring perception” to reference state ??? We know that mantra in PCT is that “ouput is not controlled” ? So how you directly control muscle force ?
> 
> RM : …that can affect the perception at any point during its production. I’m conceiving this control as being analogous to controlling for saying a particular word, as described in the “Control of Sequence” chapter of B:CP. In that model of word production there is also no prediction involved; the perceptual function just “constructs” a word based on the sequence of phonemes (analogous to the postural adjustments occurring during a “reach”) that are produced by lower level systems. It doesn’t predict what phoneme is coming next.
> 
> HB : Right. Bill changed his mind couple times about “feed-forward” (CSGnet archives) and B:CP. So you need right explanation what kind of phenomenon “prediction” or “anticipation” could be in control hierarchy ?
> 
> RM: In order to test this model we really have to come up with a clearer definition of the proposed controlled variable – which I suppose could be called “reachness”.
> 
> HB : In PCT a clear definition is in “Control perception” terms" and of course in terms of internal control. If I understand you right it seems that “reachness” seems to be “Control of behavior” insteas of term which involves references from higher levels. You “reach” with purpose. So “reachness” can’t be purpose but what you “reach for” is purposefull behavior. It has to be some internal purpose (reference) for reaching. If in PCT we are talking about purposefull behavior, every behavior generally has to have some purpose.
> 
> RM : And it really would be good to have a working model of this behavior,
> 
> HB : What ??? You need a working model for “reach” behavior ??? Working model of any behavior is already defined by Bill’s Powers theory PCT (Perceptual Control Theory). We just have to improve this model. We don’t need new model. This is CSGnet forum meant for exploring PCT. If you want new model establish your own forum for seeking new model of behavior.
> 
> PCT Definitions of control loop :
> 
> Bill P (B:CP):
> 
> 1. CONTROL : Achievement and maintenance of a preselected state in the controlling system, through actions on the environment that also cancel the effects of disturbances.
> 
> Bill P (B:CP):
> 
> 1. OUTPUT FUNCTION : The portion of a system that converts the magnitude or state of a signal inside the system into a corresponding set of effects on the immediate environment of the system
> 
> Bill P (LCS III):… **the output function** shown in it’s own box represents the means this system has for causing changes in it’s environment.
> 
> Bill P (LCS III):
> 
> 1. 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.
> 
> Bill P (B:CP) :
> 
> 1. INPUT FUNCTION : The portion of a system that receives signals or stimuli from outside the system, and generates a perceptual signal that is some function of the received signals or stimuli.
> 
> Bill P (B:CP) :
> 
> 1. COMPARATOR : The portion of control system that computes the magnitude and direction of mismatch between perceptual and reference signal.
> 
> Bill P (B:CP)
> 
> 1. ERROR : The discrepancy between a perceptual signal and a reference signal, which drives a control system’s output function. The discrepancy between a controlled quantity and it’s present reference level, which causes observable behavior.
> 
> Bill P (B:CP) :
> 
> 1. ERROR SIGNAL : A signal indicating the magnitude and direction of error.
> 
> ![cid:image001.jpg@01D37ABE.36063DF0]()
> 
> RM : if for no other reason than to show how a model that controls a variable that is _defined over time_ can be controlled. I believe that the most important way that PCT differs from other control models of the behavior of living systems is that it assumes that ALL behavior is control;
> 
> HB : How many times do we have to go through your nonsense that PCT is not about “control of behavior”. PCT is about “Control of perception”.
> 
> RM : And since control always involves the control of perception that means that simple behaviors involve the control of simple perceptions…
> 
> HB : But not in the sense that “involved” control of perception controls some “controlled variable” in external environment. At least in PCT.
> 
> RM : …and complex behaviors involve the control of complex perceptions – and these are usually perceptions that are defined over sometimes considerable amounts of time.
> 
> HB : From PCT diagram is clear that behavior is consequence of “Control of perception” so it does “involve” control in organism but the question is how as it can’t be seen continuosly. So it does not mean that we can control behavior (movements) as it’s mantra in PCT that we can’t control “output”.
> 
> So from any movement of LCS control can’t be seen. Or in other words. From single movements we can’t conclude what kind of control of perception is “involved” if we don’t see clear the purpose of behavior, because single movements (output) are not controlled. Or from single “control cycle” in control loop we can’t conclude what kind of control is “involved”. That’s why TCV is needed to understand “purposefull” behavior.
> 
> And TCV is:
> 
> Bill P (B:CP) :
> 
> The TCV is method for identifying control organization of nervous system….
> 
> There will be ambiguous cases : the disturbance may be only weakly opposed. That effect could be due not to poor control system but to a definition of actions that are only remotely linked to the actual controlled quantity.
> 
> For example : if when you open the window I sometimes get up and close it, you might conclude that I am controlling the position of the window when in fact I only shut it if the room gets too chilly to suit me. I could be controlling sensed temperature very precisely, when necesarry, but by a variety of means : shutting the window, turning up the termostat, putting on a sweater, or exercising. You are on the track of the right controlled quantity, but haven’t got the right definition yet. It is safest to assume that an ambiguous result from TCV is the fault of the hypotehsis and to continue looking for a better definition of the controlled quantity.
> 
> RM : This is one of the main reasons why Bill proposed a hierarchy of perceptions.
> 
> HB : Yes it’s about hierarchy of perceptions not hierarchy of “Controlled behaviors”.
> 
> RM : It was to account for the obviously hierarchical nature of behavior – behaviors “using” other behaviors to achieve their purposes;
> 
> HB : How behavior is used to achieve the purpose of sleeping. You are chewing all the time 2 behaviors upon which you built generality of theory. Your RCT theory is wrong. It’s hierarchical nature of perceptions, which can also “from time to time” involve behavior to achieve purposes. But hierarchical “control of perception” is continuous 24/7.
> 
> RM : …for example, using behaviors like running, throwing, catching and hitting to achieve the purpose of playing baseball – and for the fact that the behaviors that use other behaviors to achieve their purposes involve control of more complex perceptions than the behaviors that are being used; the perception controlled when “playing baseball” is much more complex (and defined over a much longer time period) than the perceptions controlled when running, throwing, catching and hitting.
> 
> HB : I don’t understand what you wanted to say ? “Perception is controlled” in all those behaviors you mentioned. You mentioned that there are purposes in all those activities ? So what is the purpose of the fielder (cathcer) in the baseball game ?
> 
> > HB-B: We know that both humans and cats fail to show APAs if they are taken by surprise.
> 
> RM: Yes, I noticed that. From the perspective of my model, that would result from not setting the reference for “reach” or " bilateral arm movement" or whatever the event is.
> 
> HB : Do I understand right that there are “behaviors” that have no references ? What kind of nonsense is this ?
> 
> HB : This happens a lot in my sport, racquetball. The ideal way to take a forehand shot is to do a lot of APAs that get you into position to take it off the back wall.
> 
> HB : The ideal way to take a “forehand shot” is with continuous “Control of perception”. We discussed that a lot of times when you understood PCT in 2007. You don’t control “forehand shot” as “Control of behavior” or any other shot but at best you’ll you’ll be aware of control of perception of your arm (shoulder, elbow and wrist and so on). You’ll not be aware of all movements involved in “forehand shot”. So whether your “forehand shot” is succesfull of not, depends from how good you “Control perception” of certain parts of the body. Control will happen even if you are not aware of it. Control loops can’t function without references.
> 
> Many perceptions in your “forehand movement” are controlled “automatically”. But you can reach the most perception of the movement and control them “consciously” through changing attention. So in any sport the question is which perceptions do we control to be successsfull, not which behavior do we control for example “forehand movement”. Maybe observer will see it like that, but there will be always question what is “forehand” movement" and which “forehand movement” is right. It’s like punches in karate schools. Everything is about perception and relative experiences of people. Or as Heather pointed out :
> 
> HB-B : …and really the only way you could get that to work is hierarchical control with continuous feedback…
> 
> HB : And hierarchical control is only about “Control of perception”.
> 
> RM : But sometimes I get a shot that comes at me so fast that I don’t have time to set up for a “proper forehand shot” – no APAs needed – so I just do what I can to move the racket to the ball like a beginner.
> 
> HB : Because you don’t control right perceptions and thus “timing” on the ball is wrong. You didn’t “predict” right where the ball will be in the next moment or you didn’t “predict” the “fastness” of the ball well.
> 
> Specially in sports we mostly talk about “anticipation or prediction” in game events if we talk about successful “cotntrol of perception”. Because “prediction” increase control succecss. The talents in sport usually solve the “timing” problem with minimizing perceptual control just for ex. to wrist if we talk about table tennis or tennis etc. It depends from how much time they have and how many “right perceptions” can be included in successfull perceptual control.
> 
> RM: I hope this makes some sense because I think it would really be a great area for research on control of higher level perceptual variables – variables that are defined over time.
> 
> HB : It doesn’t make any sense, because you are talking about RCT and “Control of behavior” and some “CV”, which is controled by “Control of behavior” and the result is some “Controlled Perceptual Variable” which is unexistant in PCT.
> 
> Boris
> 
> Best
> 
> Rick
> 
> > So yes, some environmental information serves to remove the surprise, kicking the control systems into gear. Is that (those) control system(s), dealing with the appearance of the target often used in the cat experiments to signal the upcoming stimulus, totally divorced from the “paw bat” ones? Should they be coupled? What happens if the expected stimulus never arrives, but the target remains? I guess there is fatigue at some point. What is the relevant question to ask?
> 
> > In populations of upper motor neurons in motor and premotor cortex, there is often activity seconds before any movement is observed. What does that mean for control systems? That’s obviously not just delay. Those populations get input from… like everwhere. Motor cortex is bonkers!
> 
> > On Fri, May 10, 2019, 11:59 Richard Marken [csgnet@lists.illinois.edu](mailto:csgnet@lists.illinois.edu) wrote:
> 
> > > [Rick Marken 2019-05-10\_11:53:31]
> 
> > > RM: Well, this has certainly been an interesting thread so far. I’m happy to see that there is a kind of consensus that the PCT explanation of apparent “anticipatory” behavior is that it is likely to be actions aimed at controlling a “higher level” controlled variable. The landslide was started by Henry Yin who said:
> > > 
> > > > HY: There’s no conflict between negative feedback and anticipatory behavior. The real question is what kind of CV do you need to produce such behavior.
> > > 
> > > RM: I think this is the right question: what kind of CV would an organism be controlling that would result in your seeing such apparently “anticipatory” behavior. Martin suggests that the CV is a sequence:
> > > 
> > > > MT: [Here is a] quick and dirty PCT approach. I start with the intention to bat at the target, which would set a reference for a sequence that could crudely be taken as “store energy, set trigger, wait, release energy when required”, or in a more general sense “Prepare, wait, execute”.
> 
> > > RM: And Erling agrees:
> > > 
> > > > EJ: I rather like Martin’s proposal for controlling a prior stage in a sequence.
> > > 
> > > RM: And I agree that the CV is something like a sequence, but not like the one Martin suggests. In the case of the an anticipatory postural adjustments (APAs) seen in the cat’s reaching behavior (described in the Sheppen and Drew paper), it seems to me that the controlled variable is the “reach” itself – an event – like a “golf swing”. An event differs from a sequence only inasmuch as it is a continuously changing sequence of lower level perceptions that is defined over time. The “reach” requires making postural changes over time that get the paw to the intended destination while maintaining balance. So I see the APAs as the initial components of this “reach” event.
> 
> > > RM: I see these APA’s as being analogous to the initial muscular movements – for example, contraction of the diaphragm - that are involved in producing a word. These movements are not outputs produced in anticipation of a future disturbance but are the outputs in a control loop that is aimed at controlling a perception of the word. The word itself, like reach, is the controlled variable – a variable that is defined over time.
> 
> > > RM: Because “reach” is defined over time it looks like the initial postural adjustments that are made to control this perception are anticipatory. But I believe that they are actually just like the outputs in any control loop – continuously acting to keep the controlled variable in a reference state, protected from disturbances. If this is the case – if APAs are actually the initial outputs of a control loop controlling a variable that is defied over time – then disturbances to these APA’s will be resisted. Heather mentions some data that is consistent with this view:
> > > 
> > > > NB-B: I suspect that the attached (Aruin, 2003) paper goes some way toward reconciling the “invariant, pre-programmed” feedforward conceptualization with the actual phenomenon: namely, it’s not really invariant (or, well, it’s not invariant in that there is a pre-programmed set of muscles activated in a pre-programmed way).
> 
> > > RM: I haven’t read the whole article carefully but apparently what Arium did was look to see whether variations in the initial the position of the body affected the nature of the APAs. And indeed it did. I see these variations in the initial position of the body as disturbances to a controlled variable (in Arium’s case it was “bilateral arm movement” rather than “reach”) and these disturbances are compensated for by the variations in the APAs.
> 
> > > RM: Of course, the idea that APAs are the outputs in a control loop controlling a variable defined over time has to be subjected to far more tests. And control models should be built to show that control of a higher level perception, like “reach”, can lead to behavior that “looks” anticipatory. So there’s some general ideas for PCT research that would be a great place to start for researchers interested in doing research on purpose!
> 
> > > 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

---

<div class="post-metadata">

**Author:** ![\_Boris\_Hartman](http://discourse.iapct.org/letter_avatar_proxy/v4/letter/_/e8c25b/32.png) [@\_Boris\_Hartman](http://discourse.iapct.org/u/_Boris_Hartman)\
**Post date:** [May 12, 2019, 5:04am UTC](http://discourse.iapct.org/t/anticipatory-postural-control/1164/39 "2019-05-12T05:04:28Z")

</div>

Hi Heather

![image002109.jpg](http://discourse.iapct.org/uploads/default/original/1X/d0c828c0981f50f8c54499d8d0ea0a9eee2b36dc.jpeg)

> **···**
>
> **From:** Heather Broccard-Bell (hebell@ucsd.edu via csgnet Mailing List) [csgnet@lists.illinois.edu](mailto:csgnet@lists.illinois.edu)  
> **Sent:** Saturday, May 11, 2019 5:07 AM  
> **To:** Richard Marken [rsmarken@gmail.com](mailto:rsmarken@gmail.com)  
> **Cc:** csgnet@lists.illinois.edu  
> **Subject:** Re: Anticipatory Postural Control
> 
> > HB-B : I think this does make sense,
> 
> > HB : Well sorry if I don’t agree with you. It doesn’t make any sense from PCT view if you meant Ricks phylosophy.
> 
> > HB-B : …and would be interesting to build. I am curious about a ‘critical experiment’ that would distinguish the PCT model from the mainstream account…
> 
> > HB : Heather. This is very good idea. I’m trying to persuade CSGnet members for years that they should do some experiments outside “chewed” tracking experiment. But nobody listen. Right time acceleration experiments would immediatelly show the difference between “PCT model from the mainstream account…”.
> 
> > BH-B : ….although it does seem to be one of these phenomena that people have described without couching it in any particular theoretical framework, so this may not be possible.
> 
> > HB : Well this is not scientific statement. You dissapointed me. It’s in Rick’s style conversation :oOnly one experiment will prove generality of theory. Although Bill used few experiments, his knowledge stratched through many sciences where knowledge was achieved though experiments and experiences with nature – final arbiter, as Bill Powers used to say. So Life experiments (as much as it is needed for scientific work not phylosophy) will prove that Powers theorethical frame is right. At least “portion” of his theory which I exctracted through my experimnets. And Rick and Powers ladies and some members don’t agree with this. While some members do agree.
> 
> > HB : Would you agree Heather with my “portion” of PCT theory.
> 
> > PCT Definitions of control loop as the core part of Glossary in B:CP :
> 
> > Bill P (B:CP):
> 
> > 1. CONTROL : Achievement and maintenance of a preselected state in the controlling system, through actions on the environment that also cancel the effects of disturbances.
> 
> > Bill P (B:CP):
> 
> > 1. OUTPUT FUNCTION : The portion of a system that converts the magnitude or state of a signal inside the system into a corresponding set of effects on the immediate environment of the system
> 
> > Bill P (LCS III):… **the output function** shown in it’s own box represents the means this system has for causing changes in it’s environment.
> 
> > Bill P (LCS III):
> 
> > 1. 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.
> 
> > Bill P (B:CP) :
> 
> > 1. INPUT FUNCTION : The portion of a system that receives signals or stimuli from outside the system, and generates a perceptual signal that is some function of the received signals or stimuli.
> 
> > Bill P (B:CP) :
> 
> > 1. COMPARATOR : The portion of control system that computes the magnitude and direction of mismatch between perceptual and reference signal.
> 
> > Bill P (B:CP)
> 
> > 1. ERROR : The discrepancy between a perceptual signal and a reference signal, which drives a control system’s output function. The discrepancy between a controlled quantity and it’s present reference level, which causes observable behavior.
> 
> > Bill P (B:CP) :
> 
> > 1. ERROR SIGNAL : A signal indicating the magnitude and direction of error.
> 
> > LCS III diagram “represent” by my oppinion somehow whole Bill Powers Life work. Book was published in 2008 and so I assumed it is well equiped with all Bill Powers knowledge he got through his long experiences with PCT. It could be around 35 years of his work. Although we could count here experiences before 1973 so that we could come to number 50 years of his work. So by my oppinion my extracted “portiosn” of his theory include his LIfe Work.
> 
> > ![cid:image001.jpg@01D37ABE.36063DF0]()
> 
> > Boris
> 
> > On Fri, May 10, 2019, 17:05 Richard Marken [csgnet@lists.illinois.edu](mailto:csgnet@lists.illinois.edu) wrote:
> 
> > > [Rick Marken 2019-05-10\_17:04:34]
> 
> > > On Fri, May 10, 2019 at 12:50 PM Heather Broccard-Bell [random.information.consultant@gmail.com](mailto:random.information.consultant@gmail.com) wrote:
> 
> > > > HB: I kind of think a lot of the problem is semantic. Some seem to be upset by the term “prediction” or “anticipation”, and I think what Rick/Henry suggest is a reasonable explanation for a _mechanism_ for what most people would call anticipation/prediction. It can’t be magic :))
> 
> > > RM: The only time I get upset by terms like “prediction” and “anticipation” is when they give the wrong impression of how the PCT model explains some behaviors. This usually happens when it “looks like” a behavior involves “prediction” or “anticipation”. For example, the behavior called “catching a fly ball” appears to involve “prediction” or “anticipation”. You can see it in the movements of the fielder in my baseball catch simulation ([https://www.mindreadings.com/ControlDemo/CatchXY.html](https://urldefense.proofpoint.com/v2/url?u=https-3A__www.mindreadings.com_ControlDemo_CatchXY.html&d=DwMFAg&c=OCIEmEwdEq_aNlsP4fF3gFqSN-E3mlr2t9JcDdfOZag&r=G2rjwc9SjlT6Blyc8su_Md8P_xOsOTRMJ5teQVBC2qU&m=LNUBBfse1XYT5wt4lQOozWJH-_DPhThycdi-FkrrdOg&s=CCmvUa4Bs1MGVhQL1wt7eZjmQaWXbrdNBPf2rvX3n_8&e=)). The fielder seems to be making “anticipatory field adjustments” (AFAs?) in anticipation of being in the proper position to catch the ball. But we have found that the fielder’s behavior can be accounted for quite well by a model that involves no prediction at all; the fielder in the ball catching demo gets to the correct position by controlling two present time perceptual variables: vertical and horizontal optical velocity.
> 
> > > RM: The PCT model I propose to account for the postural adjustments that seem to anticipate future disturbances (APAs) also involves no prediction. My model involves present time control of an event perception that I call “reach”; I didn’t define it very well because I don’t have a good idea of what it is but this event would be a _temporal pattern_ of proprioceptive sensations – sensed angles of the limbs, center of gravity, etc. This temporal pattern is a perceptual variable, just as a temporal pattern of phonemes is a perceptual variable. The “reach” control system I proposed uses variations in posture (including APAs), limb angles and muscle forces to bring this perceptual variable to the reference state (that I called “reach”) while protecting it from disturbances that can affect the perception at any point during its production. I’m conceiving this control as being analogous to controlling for saying a particular word, as described in the “Control of Sequence” chapter of B:CP. In that model of word production there is also no prediction involved; the perceptual function just “constructs” a word based on the sequence of phonemes (analogous to the postural adjustments occurring during a “reach”) that are produced by lower level systems. It doesn’t predict what phoneme is coming next.
> 
> > > RM: In order to test this model we really have to come up with a clearer definition of the proposed controlled variable – which I suppose could be called “reachness”. And it really would be good to have a working model of this behavior, if for no other reason than to show how a model that controls a variable that is _defined over time_ can be controlled. I believe that the most important way that PCT differs from other control models of the behavior of living systems is that it assumes that ALL behavior is control; And since control always involves the control of perception that means that simple behaviors involve the control of simple perceptions and complex behaviors involve the control of complex perceptions – and these are usually perceptions that are defined over sometimes considerable amounts of time. This is one of the main reasons why Bill proposed a hierarchy of perceptions. It was to account for the obviously hierarchical nature of behavior – behaviors “using” other behaviors to achieve their purposes; for example, using behaviors like running, throwing, catching and hitting to achieve the purpose of playing baseball – and for the fact that the behaviors that use other behaviors to achieve their purposes involve control of more complex perceptions than the behaviors that are being used; the perception controlled when “playing baseball” is much more complex (and defined over a much longer time period) than the perceptions controlled when running, throwing, catching and hitting.
> 
> > > > HB-B: We know that both humans and cats fail to show APAs if they are taken by surprise.
> 
> > > RM: Yes, I noticed that. From the perspective of my model, that would result from not setting the reference for “reach” or " bilateral arm movement" or whatever the event is. This happens a lot in my sport, racquetball. The ideal way to take a forehand shot is to do a lot of APAs that get you into position to take it off the back wall. But sometimes I get a shot that comes at me so fast that I don’t have time to set up for a “proper forehand shot” – no APAs needed – so I just do what I can to move the racket to the ball like a beginner.
> 
> > > RM: I hope this makes some sense because I think it would really be a great area for research on control of higher level perceptual variables – variables that are defined over time.
> 
> > > Best
> 
> > > Rick
> 
> > > > So yes, some environmental information serves to remove the surprise, kicking the control systems into gear. Is that (those) control system(s), dealing with the appearance of the target often used in the cat experiments to signal the upcoming stimulus, totally divorced from the “paw bat” ones? Should they be coupled? What happens if the expected stimulus never arrives, but the target remains? I guess there is fatigue at some point. What is the relevant question to ask?
> 
> > > > In populations of upper motor neurons in motor and premotor cortex, there is often activity seconds before any movement is observed. What does that mean for control systems? That’s obviously not just delay. Those populations get input from… like everwhere. Motor cortex is bonkers!
> 
> > > > On Fri, May 10, 2019, 11:59 Richard Marken [csgnet@lists.illinois.edu](mailto:csgnet@lists.illinois.edu) wrote:
> 
> > > > > [Rick Marken 2019-05-10\_11:53:31]
> 
> > > > > RM: Well, this has certainly been an interesting thread so far. I’m happy to see that there is a kind of consensus that the PCT explanation of apparent “anticipatory” behavior is that it is likely to be actions aimed at controlling a “higher level” controlled variable. The landslide was started by Henry Yin who said:
> > > > > 
> > > > > > HY: There’s no conflict between negative feedback and anticipatory behavior. The real question is what kind of CV do you need to produce such behavior.
> > > > > 
> > > > > RM: I think this is the right question: what kind of CV would an organism be controlling that would result in your seeing such apparently “anticipatory” behavior. Martin suggests that the CV is a sequence:
> > > > > 
> > > > > > MT: [Here is a] quick and dirty PCT approach. I start with the intention to bat at the target, which would set a reference for a sequence that could crudely be taken as “store energy, set trigger, wait, release energy when required”, or in a more general sense “Prepare, wait, execute”.
> 
> > > > > RM: And Erling agrees:
> > > > > 
> > > > > > EJ: I rather like Martin’s proposal for controlling a prior stage in a sequence.
> > > > > 
> > > > > RM: And I agree that the CV is something like a sequence, but not like the one Martin suggests. In the case of the an anticipatory postural adjustments (APAs) seen in the cat’s reaching behavior (described in the Sheppen and Drew paper), it seems to me that the controlled variable is the “reach” itself – an event – like a “golf swing”. An event differs from a sequence only inasmuch as it is a continuously changing sequence of lower level perceptions that is defined over time. The “reach” requires making postural changes over time that get the paw to the intended destination while maintaining balance. So I see the APAs as the initial components of this “reach” event.
> 
> > > > > RM: I see these APA’s as being analogous to the initial muscular movements – for example, contraction of the diaphragm - that are involved in producing a word. These movements are not outputs produced in anticipation of a future disturbance but are the outputs in a control loop that is aimed at controlling a perception of the word. The word itself, like reach, is the controlled variable – a variable that is defined over time.
> 
> > > > > RM: Because “reach” is defined over time it looks like the initial postural adjustments that are made to control this perception are anticipatory. But I believe that they are actually just like the outputs in any control loop – continuously acting to keep the controlled variable in a reference state, protected from disturbances. If this is the case – if APAs are actually the initial outputs of a control loop controlling a variable that is defied over time – then disturbances to these APA’s will be resisted. Heather mentions some data that is consistent with this view:
> > > > > 
> > > > > > NB-B: I suspect that the attached (Aruin, 2003) paper goes some way toward reconciling the “invariant, pre-programmed” feedforward conceptualization with the actual phenomenon: namely, it’s not really invariant (or, well, it’s not invariant in that there is a pre-programmed set of muscles activated in a pre-programmed way).
> 
> > > > > RM: I haven’t read the whole article carefully but apparently what Arium did was look to see whether variations in the initial the position of the body affected the nature of the APAs. And indeed it did. I see these variations in the initial position of the body as disturbances to a controlled variable (in Arium’s case it was “bilateral arm movement” rather than “reach”) and these disturbances are compensated for by the variations in the APAs.
> 
> > > > > RM: Of course, the idea that APAs are the outputs in a control loop controlling a variable defined over time has to be subjected to far more tests. And control models should be built to show that control of a higher level perception, like “reach”, can lead to behavior that “looks” anticipatory. So there’s some general ideas for PCT research that would be a great place to start for researchers interested in doing research on purpose!
> 
> > > > > 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

---

<div class="post-metadata">

**Author:** ![Evadeh](http://discourse.iapct.org/user_avatar/discourse.iapct.org/evadeh/32/2891_2.png) [@Evadeh](http://discourse.iapct.org/u/Evadeh)\
**Post date:** [May 12, 2019, 9:54am UTC](http://discourse.iapct.org/t/anticipatory-postural-control/1164/40 "2019-05-12T09:54:35Z")

</div>

[Eva de Hullu 2019-05-12\_09:51:36 UTC]Â Â

In following this discussion about anticipatory postural control, I think an important difference between PCT and the other theories mentioned is that in PCT, causality is circular, closed loop. On the first proposed level, there is only perception of here-and-now intensities. I think one of the reasons why other theories struggle so much to fit observations into their theory, is because of their effort to model closed-loop events into linear causal models. In that way, you’ll need difficult models with prediction and anticipation, that can be explained by PCT through the perceptual hierarchy.Â

How could we go from a here-and-now perception to the perceived “anticipatory behavior”?

I think we could have a better understanding through the perceptual hierarchy, where levels are build from the bottom up, layer by layer, into increasing complexity. In answering these kind of questions, we could use some help from the proposed hierarchy.Â

Going up in the hierarchy, the perception of time emerges when transitions become a way of making sense of changing configurations. The sequence level is several steps higher, and at this level prediction must take place.

Imagine a melody, where each note is followed by another note at a certain pace and pitch. When you hear a melody for the first time, there are no references yet for this melody, and you’ll not experience the sense of predicting the next note. But after listening to it carefully, you’ll have created references for the melody, and with these references you’ll have the sense of being able to predict what follows. If you hear a familiar melody, your references and perceptual input will match if they are equal. If the melody changes from your expectations, you’ll find that you can no longer predict what’s next; without references for the melody, you’ll not recognize the song.

Following this, the anticipatory postural control could just concist of references in the form of sequential perceptions. In a melody, the sequence is a way of organizing single notes (categories) in such a way that they are no longer just single notes, but also a melody. A movement such as reaching, is not just a single pose, but also a sequence of poses. If you look at what happens from the perspective of circular causality, interpreting the steps in the sequence as (existing) references, I believe PCT is perfectly able to explain what happens.

Eva

PS I’m conscious that I might be repeating or missing some of the things already said here. I waited a bit too long submitting this answer, so excuse me if I’ve not properly addressed or incorporated other replies.Â

> **···**
>
> On Sat, May 11, 2019 at 9:00 PM Richard Marken [csgnet@lists.illinois.edu](mailto:csgnet@lists.illinois.edu) wrote:
> 
> > [Rick Marken 2019-05-11\_11:58:37]
> 
> > On Fri, May 10, 2019 at 8:05 PM Heather Broccard-Bell [random.information.consultant@gmail.com](mailto:random.information.consultant@gmail.com) wrote:
> 
> > > HB-B: I think this does make sense, and would be interesting to build. I am curious about a ‘critical experiment’ that would distinguish the PCT model from the mainstream account… although it does seem to be one of these phenomena that people have described without couching it in any particular theoretical framework, so this may not be possible.
> 
> > 
> 
> > RM: I think the APA phenomenon is implicitly couched in a particular theoretical framework; that of an open-loop causal model of behavior. The implication is that the APA is an output that is being produced open-loop in anticipation of a future perturbation. This can be tested because my model assumes that APAs are actually controlled variables that are used to control another controlled variable – the event called “reaching”. So applying an appropriately gentle, varying force disturbance to the postural change being made during the period of the APA should be resisted. This resistance should be detectable as appropriate variation in the force exerted by the animal during the APA period – the force used to produce the APA. It should also be detectable as consistency of the APA on different trials with different disturbances; this could be determined by analysis of visual records to see if the variation in the APA over trials is what would be expected based on variatoin in teh disturbances.Â
> 
> > 
> 
> > RM: I think there might be a way to create a “portable demo” of behavior that seems to involve an APA. I’ll see if I can think of one.
> 
> > 
> 
> > BestÂ
> 
> > 
> 
> > Rick
> 
> > Â
> 
> > > On Fri, May 10, 2019, 17:05 Richard Marken [csgnet@lists.illinois.edu](mailto:csgnet@lists.illinois.edu) wrote:
> 
> > > > [Rick Marken 2019-05-10\_17:04:34]
> 
> > > >
> 
> > > > On Fri, May 10, 2019 at 12:50 PM Heather Broccard-Bell [random.information.consultant@gmail.com](mailto:random.information.consultant@gmail.com) wrote:
> 
> > > > > HB: I kind of think a lot of the problem is semantic. Some seem to be upset by the term “prediction” or “anticipation”, and I think what Rick/Henry suggest is a reasonable explanation for a _mechanism_ for what most people would call anticipation/prediction. It can’t be magic :))
> 
> > > >
> 
> > > > RM: The only time I get upset by terms like “prediction” and “anticipation” is when they give the wrong impression of how the PCT model explains some behaviors. This usually happens when it “looks like” a behavior involves “prediction” or “anticipation”.  For example, the behavior called “catching a fly ball” appears to involve “prediction” or “anticipation”. You can see it in the movements of the fielder in my baseball catch simulation ([https://www.mindreadings.com/ControlDemo/CatchXY.html](https://urldefense.proofpoint.com/v2/url?u=https-3A__www.mindreadings.com_ControlDemo_CatchXY.html&d=DwMFaQ&c=OCIEmEwdEq_aNlsP4fF3gFqSN-E3mlr2t9JcDdfOZag&r=G2rjwc9SjlT6Blyc8su_Md8P_xOsOTRMJ5teQVBC2qU&m=PbfwEFL0GWAOtua_z308wu25wa5iRh0X5XCd75HQ6h0&s=BweiZpj6gIy8TYtdnbDD35CZJjWXWHnGtNZBj7pD-mY&e=)). The fielder seems to be making “anticipatory field adjustments” (AFAs?) in anticipation of being in the proper position to catch the ball. But we have found that the fielder’s behavior can be accounted for quite well by a model that involves no prediction at all; the fielder in the ball catching demo gets to the correct position by controlling two present time perceptual variables: vertical and horizontal optical velocity.Â
> 
> > > >
> 
> > > > RM: The PCT model I propose to account for the postural adjustments that seem to anticipate future disturbances (APAs) also involves no prediction. My model involves present time control of an event perception that I call “reach”; I didn’t define it very well because I don’t have a good idea of what it is but this event would be a _temporal pattern_ of proprioceptive sensations – sensed angles of the limbs, center of gravity, etc. This temporal pattern is a perceptual variable, just as a temporal pattern of phonemes is a perceptual variable. The “reach” control system I proposed uses variations in posture (including APAs), limb angles and muscle forces to bring this perceptual variable to the reference state (that I called “reach”) while protecting it from disturbances that can affect the perception at any point during its production. I’m conceiving this control as being analogous to controlling for saying a particular word, as described in the “Control of Sequence” chapter of B:CP. In that model of word production there is also no prediction involved; the perceptual function just “constructs” a word based on the sequence of phonemes (analogous to the postural adjustments occurring during a “reach”) that are produced by lower level systems. It doesn’t predict what phoneme is coming next.
> 
> > > >
> 
> > > > RM: In order to test this model we really have to come up with a clearer definition of the proposed controlled variable – which I suppose could be called “reachness”. And it really would be good to have a working model of this behavior, if for no other reason than to show how a model that controls a variable that is _defined over time_ can be controlled. I believe that the most important way that PCT differs from other control models of the behavior of living systems is that it assumes that ALL behavior is control; And since control always involves the control of perception that means that simple behaviors involve the control of simple perceptions and complex behaviors involve the control of complex perceptions – and these are usually perceptions that are defined over sometimes considerable amounts of time. This is one of the main reasons why Bill proposed a hierarchy of perceptions. It was to account for the obviously hierarchical nature of behavior – behaviors “using” other behaviors to achieve their purposes; for example, using behaviors like running, throwing, catching and hitting to achieve the purpose of playing baseball – and for the fact that the behaviors that use other behaviors to achieve their purposes involve control of more complex perceptions than the behaviors that are being used;Â the perception controlled when “playing baseball” is much more complex (and defined over a much longer time period) than the perceptions controlled when running, throwing, catching and hitting.
> 
> > > >
> 
> > > > > HB-B: We know that both humans and cats fail to show APAs if they are taken by surprise.Â
> 
> > > >
> 
> > > > RM: Yes, I noticed that. From the perspective of my model, that would result from not setting the reference for “reach” or " bilateral arm movement" or whatever the event is. This happens a lot in my sport, racquetball. The ideal way to take a forehand shot is to do a lot of APAs that get you into position to take it off the back wall. But sometimes I get a shot that comes at me so fast that I don’t have time to set up for a “proper forehand shot” – no APAs needed – so I just do what I can to move the racket to the ball like a beginner. Â
> 
> > > >
> 
> > > > RM: I hope this makes some sense because I think it would really be a great area for research on control of higher level perceptual variables – variables that are defined over time.Â
> 
> > > >
> 
> > > > Best
> 
> > > >
> 
> > > > Rick
> 
> > > >
> 
> > > > > So yes, some environmental information serves to remove the surprise, kicking the control systems into gear. Is that (those) control system(s), dealing with the appearance of the target often used in the cat experiments to signal the upcoming stimulus, totally divorced from the “paw bat” ones? Should they be coupled? What happens if the expected stimulus never arrives, but the target remains? I guess there is fatigue at some point. What is the relevant question to ask?
> 
> > > > >
> 
> > > > > In populations of upper motor neurons in motor and premotor cortex, there is often activity seconds before any movement is observed. What does that mean for control systems? That’s obviously not just delay. Those populations get input from… like everwhere. Motor cortex is bonkers! Â
> 
> > > > >
> 
> > > > >
> 
> > > > > On Fri, May 10, 2019, 11:59 Richard Marken [csgnet@lists.illinois.edu](mailto:csgnet@lists.illinois.edu) wrote:
> 
> > > > > > [Rick Marken 2019-05-10\_11:53:31]
> 
> > > > > >
> 
> > > > > > RM: Well, this has certainly been an interesting thread so far. I’m happy to see that there is a kind of consensus that the PCT explanation of apparent “anticipatory” behavior is that it is likely to be actions aimed at controlling a “higher level” controlled variable. The landslide was started by Henry Yin who said:
> > > > > > 
> > > > > > > HY: There’s no conflict between negative feedback and anticipatory behavior. The real question is what kind of CV do you need to produce such behavior.
> > > > > > 
> > > > > > RM: I think this is the right question: what kind of CV would an organism be controlling that would result in your seeing such apparently "anticipatory"Â behavior. Martin suggests that the CV is a sequence:
> > > > > > 
> > > > > > > MT: [Here is a] quick and dirty PCT approach. I start with the intention to bat at the target, which would set a reference for a sequence that could crudely be taken as “store energy, set trigger, wait, release energy when required”, or in a more general sense “Prepare, wait, execute”.
> 
> > > > > > RM: And Erling agrees:
> > > > > > 
> > > > > > > EJ: Â I rather like Martin’s proposal for controlling a prior stage in a sequence. Â
> > > > > > 
> > > > > > RM: And I agree that the CV is something like a sequence, but not like the one Martin suggests. In the case of the an anticipatory postural adjustments (APAs) seen in the cat’s reaching behavior (described in the Sheppen and Drew paper), it seems to me that the controlled variable is the “reach” itself – an event – like a “golf swing”. An event differs from a sequence only inasmuch as it is a continuously changing sequence of lower level perceptions that is defined over time. The “reach” requires making postural changes over time that get the paw to the intended destination while maintaining balance. So I see the APAs as the initial components of this “reach” event.Â
> 
> > > > > >
> 
> > > > > > RM: I see these APA’s as being analogous to the initial muscular movements – for example, contraction of the diaphragm - that are involved in producing a word. These movements are not outputs produced in anticipation of a future disturbance but are the outputs in a control loop that is aimed at controlling a perception of the word. The word itself, like reach, is the controlled variable – a variable that is defined over time.Â
> 
> > > > > >
> 
> > > > > > RM: Because “reach” is defined over time it looks like the initial postural adjustments that are made to control this perception are anticipatory. But I believe that they are actually just like the outputs in any control loop – continuously acting to keep the controlled variable in a reference state, protected from disturbances. If this is the case – if APAs are actually the initial outputs of a control loop controlling a variable that is defied over time – then disturbances to these APA’s will be resisted. Heather mentions some data that is consistent with this view:
> > > > > > 
> > > > > > > NB-B: I suspect that the attached (Aruin, 2003) paper goes some way toward reconciling the “invariant, pre-programmed” feedforward conceptualization with the actual phenomenon: namely, it’s not really invariant (or, well, it’s not invariant in that there is a pre-programmed set of muscles activated in a pre-programmed way). Â
> 
> > > > > > RM: I haven’t read the whole article carefully but apparently what Arium did was look to see whether variations in the initial the position of the body affected the nature of the APAs. And indeed it did. I see these variations in the initial position of the body as disturbances to a controlled variable (in Arium’s case it was “bilateral arm movement” rather than “reach”) and these disturbances are compensated for by the variations in the APAs.Â
> 
> > > > > >
> 
> > > > > > RM: Of course, the idea that APAs are the outputs in a control loop controlling a variable defined over time has to be subjected to far more tests. And control models should be built to show that control of a higher level perception, like “reach”, can lead to behavior that “looks” anticipatory. So there’s some general ideas for PCT research that would be a great place to start for researchers interested in doing research on purpose!
> 
> > > > > >
> 
> > > > > > BestÂ
> 
> > > > > >
> 
> > > > > > Rick
> 
> > > > > > Â
> 
> > > > > >
> 
> > > > > >
> 
> > > > > >
> 
> > > > > > –  
> > > > > > Richard S. MarkenÂ
> 
> > > > > > "Perfection is achieved not when you have nothing more to add, but when you  
> > > > > > have nothing left to take away.�  
> > > > > > Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â --Antoine de Saint-Exupery
> 
> > > >
> 
> > > > –  
> > > > Richard S. MarkenÂ
> 
> > > > "Perfection is achieved not when you have nothing more to add, but when you  
> > > > have nothing left to take away.�  
> > > > Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â --Antoine de Saint-Exupery
> 
> > 
> 
> > –  
> > Richard S. MarkenÂ
> 
> > "Perfection is achieved not when you have nothing more to add, but when you  
> > have nothing left to take away.�  
> > Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â --Antoine de Saint-Exupery

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