# Ruminations on Importance

**URL:** <http://discourse.iapct.org/t/ruminations-on-importance/10094>\
**Category:** CSG2003\
**Created:** [June 27, 2003, 3:32pm UTC](http://discourse.iapct.org/t/ruminations-on-importance/10094 "2003-06-27T15:32:55Z")\
**Posts on this page:** 20\
**Page:** 2

<div class="post-metadata">

**Author:** ![Richard\_Marken2](http://discourse.iapct.org/letter_avatar_proxy/v4/letter/r/edb3f5/32.png) [@Richard\_Marken2](http://discourse.iapct.org/u/Richard_Marken2)\
**Post date:** [June 29, 2003, 3:36pm UTC](http://discourse.iapct.org/t/ruminations-on-importance/10094/21 "2003-06-29T15:36:23Z")

</div>

[From Rick Marken (2003.06.29.0840)]

> Bill Powers (2003.06.29.0637 MDT)–  
> Bruce Gregory (2003.0628.2136)–

> > I’m afraid I can’t  
> > do any better than my last two posts. I suggest that we drop the issue.  
> > I think that if you tried to state the problem clearly and  
> > as completely as possible, you might see something that explains the difficulty,  
> > or see a lead to answering your own questions. That kind of answer will  
> > stick with you for a long time.  
> > Good advice for all of us.  
> > [Mary says: “At the blah-blah-blah  
> > level, HPCT is no better than any other theory”]  
> > I think I will put that up at the CSG Website. I was trying to figure out  
> > how to say this and Mary has, once again, hit the nail on the head.  
> > I don’t agree with Rick that the spreadsheet  
> > model, or any simulation, could be directly applied here. Most likely he  
> > didn’t mean that. We can’t write the equations for the sorts of control  
> > systems we’re talking about. There are some useful principles there, such  
> > as the one saying that lower-order goals are set so as to help satisfy  
> > many higher goals at the same time, but that’s about as close as we can  
> > get to equations.  
> > Yes. It’s the principles illustrated by the spreadsheet model – particularly  
> > the fact that higher order systems can control without any conflict with  
> > the lower level systems that are the means of higher order control – to  
> > which I was referring.  
> > As you can see, it’s hard for me to  
> > accept the proposal that we just drop the issue. I’m willing to help, but  
> > I don’t think it’s unreasonable to expect that a learner will put forth  
> > as much effort as needed. If it’s OK with you just to drop the subject,  
> > how important was the question in the first place?  
> > Good question.  
> > Best regards

Rick

> **···**
>
> –
> 
> Richard S. Marken
> 
> [MindReadings.com](http://MindReadings.com)
> 
> [marken@mindreadings.com](mailto:marken@mindreadings.com)
> 
> 310 474-0313

---

<div class="post-metadata">

**Author:** ![Bruce\_Gregory4](http://discourse.iapct.org/letter_avatar_proxy/v4/letter/b/7feea3/32.png) [@Bruce\_Gregory4](http://discourse.iapct.org/u/Bruce_Gregory4)\
**Post date:** [June 29, 2003, 5:24pm UTC](http://discourse.iapct.org/t/ruminations-on-importance/10094/22 "2003-06-29T17:24:36Z")

</div>

[From Bruce Gregory (2003.0629.1323)]

[From Rick Marken (2003.06.29.0840)]

Bill Powers (2003.06.29.0637 MDT)--

Bruce Gregory (2003.0628.2136)--

I'm afraid I can't do any better than my last two posts. I suggest that we drop the issue.

I think that if you tried to state the problem clearly and as completely as possible, you might see something that explains the difficulty, or see a lead to answering your own questions. That kind of answer will stick with you for a long time.

Good advice for all of us.

[Mary says: "At the blah-blah-blah level, HPCT is no better than any other theory"]

I think I will put that up at the CSG Website. I was trying to figure out how to say this and Mary has, once again, hit the nail on the head.

As you can see, it's hard for me to accept the proposal that we just drop the issue. I'm willing to help, but I don't think it's unreasonable to expect that a learner will put forth as much effort as needed. If it's OK with you just to drop the subject, how important was the question in the first place?

Good question.

Would you consider keeping your billets-doux private? Some of us find them embarrassing. Thanks for considering this request.

---

<div class="post-metadata">

**Author:** ![Bruce\_Gregory4](http://discourse.iapct.org/letter_avatar_proxy/v4/letter/b/7feea3/32.png) [@Bruce\_Gregory4](http://discourse.iapct.org/u/Bruce_Gregory4)\
**Post date:** [June 29, 2003, 6:05pm UTC](http://discourse.iapct.org/t/ruminations-on-importance/10094/23 "2003-06-29T18:05:29Z")

</div>

[From Bruce gregory (2003.0629.1404)]

from Bill Powers (2003.06.29.0637 MDT)

Bruce Gregory (2003.0628.2136)--

I'm afraid I can't do any better than my last two posts. I suggest that we drop the issue.

As you wish. I hope that you won't be referring to this issue in the future as a case that HPCT can't handle.

If I have learned anything, it is that there is no case that HPCT cannot handle.

[Mary says: "At the blah-blah-blah level, HPCT is no better than any other theory"]

Mary should know.

It is possible to see in the spreadsheet (or equivalent) model that interactions among control systems at the same level, due to sharing of lower-order systems, do not amount to conflict unless they require that the higher systems produce their maximum possible outputs (which puts an end to controlling because the outputs can no longer vary in response to disturbances). Short of that extreme situation, what we have is a group of control systems keeping their own error signals as small as possible with the result that that total error across all systems is as low as it can be given the current system parameters and environment. That is the normal state of the hierarchy: not zero error, but as little error as possible.

I think my question involved how large "as little error as possible" a biological system can tolerate with regard to some control systems.

Add to this the principle that higher-order systems tell lower ones what to sense (by adjusting their reference signals), while the lower systems act autonomously and rapidly to bring their own perceptions to the requested levels and counteract disturbances while keeping the perceptions at those (constant or varying) levels. It might also be appropriate to suppose that higher systems can adjust parameters like gain in those lower systems, although those higher systems would be concerned with different controlled variables.

As you can see, it's hard for me to accept the proposal that we just drop the issue. I'm willing to help, but I don't think it's unreasonable to expect that a learner will put forth as much effort as needed. If it's OK with you just to drop the subject, how important was the question in the first place?

I have in fact resolved the problem to my satisfaction. On the off chance someone else might be interested, here is my thinking. The hierarchy controls the distance to car in front of me by using the throttle and the brakes. Normally, the reference level for that distance is set by higher-order systems at a minimum of six car lengths. This distance is not controlled 'thightly' - the gain is not terribly high so the distance can vary by one or two car lengths. My attention is 'free to wander'. Occasionally, however, traffic is very heavy and the reference distance is reset to roughly two car lengths. This distance is controlled with much higher gain and my attention is focused much more closely on maintaining a minimum distance of one car length. My conjecture is that the higher gain is established by the importance of not hitting the car in front of me when the nominal distance is quite small. This higher gain and the associated attention I give to the task is established by the limbic system.

---

<div class="post-metadata">

**Author:** ![Richard\_Marken2](http://discourse.iapct.org/letter_avatar_proxy/v4/letter/r/edb3f5/32.png) [@Richard\_Marken2](http://discourse.iapct.org/u/Richard_Marken2)\
**Post date:** [June 29, 2003, 6:11pm UTC](http://discourse.iapct.org/t/ruminations-on-importance/10094/24 "2003-06-29T18:11:04Z")

</div>

[From Rick Marken (2003.06.29.1110)]

> Bruce Gregory (2003.0629.1323)--
> 
> Would you consider keeping your billets-doux private? Some of us find them embarrassing.

Who is "some of us" ? I can see why you would find Bill's and my comments embarrassing since they expose your substanceless hostility toward PCT but I'm curious to know who else does.

Best

Rick

> **···**
>
> --  
> Richard S. Marken  
> MindReadings.com  
> marken@mindreadings.com  
> 310 474-0313

---

<div class="post-metadata">

**Author:** ![Bruce\_Gregory4](http://discourse.iapct.org/letter_avatar_proxy/v4/letter/b/7feea3/32.png) [@Bruce\_Gregory4](http://discourse.iapct.org/u/Bruce_Gregory4)\
**Post date:** [June 29, 2003, 6:28pm UTC](http://discourse.iapct.org/t/ruminations-on-importance/10094/25 "2003-06-29T18:28:49Z")

</div>

[From Bruce Gregory (2003.0629.1428)]

> Rick Marken (2003.06.29.1110)
> 
> > Bruce Gregory (2003.0629.1323)--
> > 
> > Would you consider keeping your billets-doux private? Some of us find  
> > them embarrassing.
> 
> Who is "some of us" ? I can see why you would find Bill's and my  
> comments embarrassing since they expose your substanceless hostility  
> toward PCT but I'm curious to know who else does.

Look up the word "billets-doux." You seem to have missed the point.

---

<div class="post-metadata">

**Author:** ![Richard\_Marken2](http://discourse.iapct.org/letter_avatar_proxy/v4/letter/r/edb3f5/32.png) [@Richard\_Marken2](http://discourse.iapct.org/u/Richard_Marken2)\
**Post date:** [June 29, 2003, 10:56pm UTC](http://discourse.iapct.org/t/ruminations-on-importance/10094/26 "2003-06-29T22:56:25Z")

</div>

[From Rick Marken (2003.06.29.1600)]

> Bruce Gregory (2003.0629.1428)--
> 
> \> Rick Marken (2003.06.29.1110)  
> \>  
> \>\> Bruce Gregory (2003.0629.1323)--  
> \>\>  
> \>\> Would you consider keeping your billets-doux private? Some of us find  
> \>\> them embarrassing.  
> \>  
> \> Who is "some of us" ? I can see why you would find Bill's and my  
> \> comments embarrassing since they expose your substanceless hostility  
> \> toward PCT but I'm curious to know who else does.
> 
> Look up the word "billets-doux." You seem to have missed the point.

I got the point. My point was that your embarrassment comes from the fact  
that our comments expose your ill-informed hostility towards PCT, not from  
their being love notes.

Best regards

Rick

> **···**
>
> --  
> Richard S. Marken  
> MindReadings.com  
> marken@mindreadings.com  
> 310 474-0313

---

<div class="post-metadata">

**Author:** ![Richard\_Marken2](http://discourse.iapct.org/letter_avatar_proxy/v4/letter/r/edb3f5/32.png) [@Richard\_Marken2](http://discourse.iapct.org/u/Richard_Marken2)\
**Post date:** [June 29, 2003, 11:07pm UTC](http://discourse.iapct.org/t/ruminations-on-importance/10094/27 "2003-06-29T23:07:00Z")

</div>

[From Rick Marken (2003.06.29.1610)]

> Bruce gregory (2003.0629.1404)--
> 
> &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Bill Powers (2003.06.29.0637 MDT)
> 
> &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;As you can see, it's hard for me to accept the proposal that we just drop the issue. I'm willing to help, but I don't think it's unreasonable to expect that a learner will put forth as much effort as needed. If it's OK with you just to drop the subject, how important was the question in the first place?
> 
> I have in fact resolved the problem to my satisfaction. On the off chance someone else might be interested, here is my thinking. The hierarchy controls the distance to car in front of me by using the throttle and the brakes. Normally, the reference level for that distance is set by higher-order systems at a minimum of six car lengths. This distance is not controlled 'thightly' - the gain is not terribly high so the distance can vary by one or two car lengths. My attention is 'free to wander'.

Why is your attention free to wander when control gain is low but not when it is high? This conclusion must be based on some mechanism you are thinking of. What is it?

> Occasionally, however, traffic is very heavy and the reference distance is reset to roughly two car lengths. This distance is controlled with much higher gain and my attention is focused much more closely on maintaining a minimum distance of one car length. My conjecture is that the higher gain is established by the importance of not hitting the car in front of me when the nominal distance is quite small. This higher gain and the associated attention I give to the task is established by the limbic system.

How does the limbic system do it? An explanation of a phenomenon (like increased gain and attention when you are following closely in dense traffic, assuming that that is a phenomenon) requires more than saying that it s handled by a particular part of the brain.

Best

Rick

> **···**
>
> --  
> Richard S. Marken  
> MindReadings.com  
> marken@mindreadings.com  
> 310 474-0313

---

<div class="post-metadata">

**Author:** ![Bill\_Powers](http://discourse.iapct.org/letter_avatar_proxy/v4/letter/b/a183cd/32.png) [@Bill\_Powers](http://discourse.iapct.org/u/Bill_Powers)\
**Post date:** [June 30, 2003, 4:34am UTC](http://discourse.iapct.org/t/ruminations-on-importance/10094/28 "2003-06-30T04:34:45Z")

</div>

> I have in fact resolved the problem  
> to my satisfaction. … My conjecture is that the higher gain is  
> established by the importance of not hitting the car in front of me when  
> the nominal distance is quite small. This higher gain and the associated  
> attention I give to the task is established by the limbic  
> system.  
> [From Bill Powers (2003.06.29.2221MDT)]

Bruce gregory (2003.0629.1404)–

Importance can establish higher gain? The limbic system establishes  
attention? The limbic system can tell how important the nominal distance  
between cars is? If this is what you call a resolution of the problem, I  
can see that it would have taken me a long time to figure out what you’d  
be satisfied with.

I take it that I can stop trying now.

Best,

Bill P.

---

<div class="post-metadata">

**Author:** ![Bruce\_Gregory4](http://discourse.iapct.org/letter_avatar_proxy/v4/letter/b/7feea3/32.png) [@Bruce\_Gregory4](http://discourse.iapct.org/u/Bruce_Gregory4)\
**Post date:** [June 30, 2003, 9:39am UTC](http://discourse.iapct.org/t/ruminations-on-importance/10094/29 "2003-06-30T09:39:57Z")

</div>

[From Bruce Gregory (2003.0630.0540)]

Bill Powers (2003.06.29.2221MDT)

> Bruce gregory (2003.0629.1404)--
> 
> > I have in fact resolved the problem to my satisfaction. ... My  
> > conjecture is that the higher gain is established by the importance of  
> > not hitting the car in front of me when the nominal distance is quite  
> > small. This higher gain and the associated attention I give to the  
> > task is established by the limbic system.
> 
> Importance can establish higher gain? The limbic system establishes  
> attention? The limbic system can tell how important the nominal distance  
> between cars is? If this is what you call a resolution of the problem, I  
> can see that it would have taken me a long time to figure out what you'd  
> be satisfied with.
> 
> I take it that I can stop trying now.

Please. Even reading seems to be too much of a challenge at this point.

> **···**
>
> --  
> Bruce Gregory lives with the poet and painter Gray Jacobik in the future  
> Canadian Province of New England.
> 
> www.joincanadanow.org

---

<div class="post-metadata">

**Author:** ![David\_Goldstein1](http://discourse.iapct.org/letter_avatar_proxy/v4/letter/d/58f4c7/32.png) [@David\_Goldstein1](http://discourse.iapct.org/u/David_Goldstein1)\
**Post date:** [June 30, 2003, 10:17am UTC](http://discourse.iapct.org/t/ruminations-on-importance/10094/30 "2003-06-30T10:17:48Z")

</div>

[From David Goldstein (2003.06.30 EDT)]

[From Bill Powers (2003.06.27.1407 MDT]

Bruce Gregory (2003.0627.1217)–

I know that I am a Johnny-come-lately to the discussion. However, I  
think that Bruce is bringing up some interesting issues. What is the role of  
emotion when it comes to the question of what we pay attention to?

Bill, you mention that you notice that your muscles become tense when  
the traffic is heavy.

Isn’t this because you are afraid that the chances of an accident  
are higher and that you don’t want to be in an accident with all that  
implies?

Might not this be a case where the Observer enters the picture?

Yes, I want to get to the meeting on time. Yes, I want to advance my  
career.

But my life is more important than all of that.

No conflict, I put my foot on the brake.

I will be late, but I live to fight another day.

David

> **···**
>
> -----Original Message-----  
> **From:** Control Systems Group  
> Network (CSGnet) [[mailto:CSGNET@listserv.uiuc.edu](mailto:CSGNET@listserv.uiuc.edu)] **On Behalf Of** Bill Powers  
> **Sent:** Friday, June 27, 2003 5:08  
> PM  
> **To:** CSGNET@listserv.uiuc.edu  
> **Subject:** Re: Ruminations on  
> Importance
> 
> [From Bill Powers (2003.06.27.1407 MDT]
> 
> Bruce Gregory (2003.0627.1217)–
> 
> This particular fire hydrant has always had trouble  
> understanding how
> 
> the control hierarchy ‘decides’ which perception to control and, in
> 
> particular, how it rapidly shifts from controlling one perception to
> 
> controlling another without the delays associated with relying on upper
> 
> levels in the hierarchy to reset reference levels.
> 
> I don’t think we control just one variable at a time – or am I misreading what  
> you mean?
> 
> When I look up from tuning my car radio and see  
> the brake lights of the car in front of me, how does the perceptual hierarchy  
> know enough to slam on my brakes?
> 
> I don’t understand this way of asking the question. It knows everything you  
> know, doesn’t it? If a higher system in you has temporarily removed visual  
> inputs from the distance-keeping control system, that system won’t perceive any  
> brake lights until you restore the visual inputs. If you look up after the  
> distance has decreased significantly below the range you normally maintain,  
> there will be an abnormally large distance error which should lead to a more  
> energetic braking action than usual. If there is still plenty of distance to  
> the car ahead, you’ll just brake normally, won’t you? That’s what I do.
> 
> When the traffic is dicey, how does the perceptual  
> hierarchy know that
> 
> I can’t afford to direct my attention to looking for a cassette to
> 
> play? It has always seemed from my lowly position that the hierarchy is
> 
> extremely capable but lacking in much sense of what is important at the
> 
> moment.
> 
> I liked Rick’s answer to this. Since we’re dealing with a hypothetical case, it  
> has exactly as much sense as you choose to give it by proposing details for  
> your model.
> 
> The way I would answer this question would be to look at how _I_ know that I  
> should pay more attention to traffic when it looks bad. When I see a lot of  
> cars nearby, I watch other cars and the road more, and look only very briefly  
> at objects or people inside the car, if at all. I think I tense up a little,  
> too, which moves the motor systems toward the centers of their operating ranges  
> as well as making the muscles stiffer. It may be that I also raise the gain of  
> the control systems involved in controlling spatial relationships. The result  
> is that I control with less error, counteracting smaller disturbances and  
> continuing to control until the errors are smaller than they usually are. Why  
> do I do this? Because the spaces between cars are smaller than usual and my  
> normal control actions allow the car to get too close to others or to  
> obstacles. The errors actually get bigger, so I have to raise my control gain  
> to keep them as small as I want them. It’s not hard to imagine a higher-order  
> control system that does this sort of thing, is it?
> 
> To the extent that this assessment is not wholly  
> without merit, I offer
> 
> the following questions. Could it be that the limbic system functions
> 
> to tell the control hierarchy what is important ‘right now’? ]
> 
> I’m not guessing about which parts of the brain are involved. Whatever brain  
> structure we propose as containing the needed control systems, it would have to  
> be able to perceive changes in the organism’s relationship to the environment  
> and detect whatever errors those changes create, and automatically alter  
> reference signals and/or system parameters in motor systems in the way required  
> to make the errors smaller. If the limbic system can do all those things, it  
> may be where that sort of control takes place. I wouldn’t know.
> 
> Further, could it be that the mechanism employed by  
> the limbic system to convey
> 
> this information consists of increasing the gain on some control loops
> 
> and reducing the gain on others?
> 
> Certainly. I have long said that higher systems may well act by varying the  
> parameters of lower systems as well as their reference signals. An early demo  
> of this effect was offered by Tom Bourbon at my suggestion, 10 or 15 years ago.  
> He set up a model in which a higher-level system monitored the average absolute  
> value of error signal in a control system, and varied the output gain in that  
> system to achieve minimum error. Actually, he set this up as a reorganization  
> task, so the gain variations were done through a random walk. More recently, I  
> proposed a model in which an auxiliary control system (whether you should  
> consider it “higher” or not is debatable) changes the weightings in  
> an output function in a way that emulates the convolution theorem. It worked  
> pretty well when embedded in the Little Man model. I called this model the  
> “artificial cerebellum,” because of some resemblances of the  
> algorithm to processes known to happen in the cerebellum. Of could this doesn’t  
> mean that the amygdala could not do something similar. However, my modeling  
> efforts focus on what kind of control process is done, which doesn’t depend on  
> guessing which part of the brain does it.
> 
> These questions do not seem totally implausible  
> on the basis of what little I know about the wiring of the brain.
> 
> They seem plausible to me, too.
> 
> Best,
> 
> Bill P.

---

<div class="post-metadata">

**Author:** ![Bruce\_Gregory4](http://discourse.iapct.org/letter_avatar_proxy/v4/letter/b/7feea3/32.png) [@Bruce\_Gregory4](http://discourse.iapct.org/u/Bruce_Gregory4)\
**Post date:** [June 30, 2003, 10:33am UTC](http://discourse.iapct.org/t/ruminations-on-importance/10094/31 "2003-06-30T10:33:02Z")

</div>

[From Bruce Gregory (2003.0630.0632)]

Rick Marken (2003.06.29.1600)

> I got the point.

Good for you!

My point was that your embarrassment comes from the fact

> that our comments expose your ill-informed hostility towards PCT, not from  
> their being love notes.

Ill-informed, possibly. Hostility? I assume that you find me hostile  
when I point out that most PCT explanations are simply hand-waving. No  
data (except the notoriously suspect 'introspection') and no  
quantitative models. I assume that you agree since you keep pointing to  
same few papers written a decade or more ago. The oft-cited spreadsheet  
simulation demonstrates that certain hierarchical models are not  
unstable. Nothing more. Nothing less.

I have nothing against love notes. It is simply that I don't find them  
anywhere else as part of a serious scientific discussion. On the other  
hand, perhaps CSGnet is just the place for them.

> **···**
>
> --  
> Bruce Gregory lives with the poet and painter Gray Jacobik in the future  
> Canadian Province of New England.
> 
> www.joincanadanow.org

---

<div class="post-metadata">

**Author:** ![Richard\_Marken2](http://discourse.iapct.org/letter_avatar_proxy/v4/letter/r/edb3f5/32.png) [@Richard\_Marken2](http://discourse.iapct.org/u/Richard_Marken2)\
**Post date:** [June 30, 2003, 1:09pm UTC](http://discourse.iapct.org/t/ruminations-on-importance/10094/32 "2003-06-30T13:09:19Z")

</div>

[From Rick Marken (2003.06.30.0910)]

> David  
> Goldstein (2003.06.30 EDT) –

> Bill  
> Powers (2003.06.27.1407 MDT) –

> Bruce Gregory (2003.0627.1217)–

> I know  
> that I am a Johnny-come-lately to the discussion. However, I think that  
> Bruce is bringing up some interesting issues. What is the role of emotion  
> when it comes to the question of what we pay attention to

I am surprised at you David. Bruce is not bringing up interesting  
issues. He is simply attacking PCT by asserting the existence of weaknesses  
in the theory that don’t exist.

The only interesting issue Bruce brings up, as an accidental side effect  
of his superficial attacks, is why PCT engenders such hostility.

Best regards

Rick

> **···**
>
> –
> 
> Richard S. Marken, Ph.D.
> 
> Senior Behavioral Scientist
> 
> The RAND Corporation
> 
> PO Box 2138
> 
> 1700 Main Street
> 
> Santa Monica, CA 90407-2138
> 
> Tel: 310-393-0411 x7971
> 
> Fax: 310-451-7018
> 
> E-mail: [rmarken@rand.org](mailto:rmarken@rand.org)

---

<div class="post-metadata">

**Author:** ![Bruce\_Gregory4](http://discourse.iapct.org/letter_avatar_proxy/v4/letter/b/7feea3/32.png) [@Bruce\_Gregory4](http://discourse.iapct.org/u/Bruce_Gregory4)\
**Post date:** [June 30, 2003, 1:36pm UTC](http://discourse.iapct.org/t/ruminations-on-importance/10094/33 "2003-06-30T13:36:00Z")

</div>

[From Bruce Gregory (2003.0630.0934)]

> Rick Marken (2003.06.29.1610)
> 
> > Bruce gregory (2003.0629.1404)--
> > 
> > &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Bill Powers (2003.06.29.0637 MDT)
> > 
> > &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;As you can see, it's hard for me to accept the proposal that we  
> > just drop the issue. I'm willing to help, but I don't think it's  
> > unreasonable to expect that a learner will put forth as much effort  
> > as needed. If it's OK with you just to drop the subject, how  
> > important was the question in the first place?
> > 
> > I have in fact resolved the problem to my satisfaction. On the off  
> > chance someone else might be interested, here is my thinking. The  
> > hierarchy controls the distance to car in front of me by using the  
> > throttle and the brakes. Normally, the reference level for that  
> > distance is set by higher-order systems at a minimum of six car  
> > lengths. This distance is not controlled 'thightly' - the gain is not  
> > terribly high so the distance can vary by one or two car lengths. My  
> > attention is 'free to wander'.
> 
> Why is your attention free to wander when control gain is low but not  
> when it is high? This conclusion must be based on some mechanism you  
> are thinking of. What is it?

Since HPCT does not model attention, consciousness, or emotions, no  
answer I could provide would pass muster. I don't consider these  
omissions to be a "fault" of HPCT, but simply a limitation of the  
model. HPCT gets around this limitation by invoking higher-order  
control systems to minimize conflict. As far as I can tell this deus ex  
machina cannot be assailed because it is rarely modeled and therefore  
cannot be confronted with evidence. The reason no doubt has to do with  
Bills observation that most situations are too complicated to be  
modeled. I agree with Bill that HPCT is a viewpoint, and not model. We  
differ in that this viewpoint is quite limited as far as I am  
concerned. Your experience may differ.

> > Occasionally, however, traffic is very heavy and the reference  
> > distance is reset to roughly two car lengths. This distance is  
> > controlled with much higher gain and my attention is focused much  
> > more closely on maintaining a minimum distance of one car length. My  
> > conjecture is that the higher gain is established by the importance  
> > of not hitting the car in front of me when the nominal distance is  
> > quite small. This higher gain and the associated attention I give to  
> > the task is established by the limbic system.
> 
> How does the limbic system do it? An explanation of a phenomenon (like  
> increased gain and attention when you are following closely in dense  
> traffic, assuming that that is a phenomenon) requires more than saying  
> that it s handled by a particular part of the brain.

It seems to me that a skilled fellow such as yourself could provide a  
simple control model.

---

<div class="post-metadata">

**Author:** ![Richard\_Marken2](http://discourse.iapct.org/letter_avatar_proxy/v4/letter/r/edb3f5/32.png) [@Richard\_Marken2](http://discourse.iapct.org/u/Richard_Marken2)\
**Post date:** [June 30, 2003, 1:51pm UTC](http://discourse.iapct.org/t/ruminations-on-importance/10094/34 "2003-06-30T13:51:54Z")

</div>

[From Rick Marken (2003.06.30.0940)]

> Bruce Gregory (2003.0630.0632)--
> 
> Rick Marken (2003.06.29.1600)
> 
> \> My point was that your embarrassment comes from the fact  
> \> that our comments expose your ill-informed hostility towards PCT, not from  
> \> their being love notes.
> 
> Ill-informed, possibly. Hostility? I assume that you find me hostile  
> when I point out that most PCT explanations are simply hand-waving.

Yes. I do.

> No data (except the notoriously suspect 'introspection') and no  
> quantitative models.

Saying such things doesn't make them true. Why are you doing this?

> I assume that you agree since you keep pointing to  
> same few papers written a decade or more ago.

Of course I don't agree. Those papers contain data and quantitative models that  
are ust as valuable today as they were when first reported. Why are you doing  
this?

> The oft-cited spreadsheet  
> simulation demonstrates that certain hierarchical models are not  
> unstable. Nothing more. Nothing less.

I think it demonstrates quite a bit more. It certainly demonstrates some of the  
important principles of hierarchical control that are part of the HPCT model:  
control of several higher level perceptions simultaneously without conflict using  
the same set of lower level control systems, lack of conflict between systems at  
different levels of the hierarchy, higher levels controlling perceptions that are  
a function of perceptions controlled at lower levels, etc.

Best regards

Rick

> **···**
>
> --  
> Richard S. Marken, Ph.D.  
> Senior Behavioral Scientist  
> The RAND Corporation  
> PO Box 2138  
> 1700 Main Street  
> Santa Monica, CA 90407-2138  
> Tel: 310-393-0411 x7971  
> Fax: 310-451-7018  
> E-mail: rmarken@rand.org

---

<div class="post-metadata">

**Author:** ![Bill\_Powers](http://discourse.iapct.org/letter_avatar_proxy/v4/letter/b/a183cd/32.png) [@Bill\_Powers](http://discourse.iapct.org/u/Bill_Powers)\
**Post date:** [June 30, 2003, 2:00pm UTC](http://discourse.iapct.org/t/ruminations-on-importance/10094/35 "2003-06-30T14:00:49Z")

</div>

[From Bill Powers (2003.05.30.0637 MDT)]

David Goldstein  
(2003.06.30 EDT)

> I  
> know that I am a Johnny-come-lately to the discussion. However, I think  
> that Bruce is bringing up some interesting issues. What is the role of  
> emotion when it comes to the question of what we pay attention  
> to?

The way I have it worked out, emotion is what we experience after an  
error signal has led to preparing the somatic system for action. It might  
enter shortly after you have looked up to see the car ahead only two car  
lengths away and approaching at an accelerating rate, and are in the  
process of jamming the brake through the floor. You may not actually feel  
any emotion until well after you’ve saved yourself from a wreck.

Do you agree on this sequence, or do you, too, claim that the amygdala  
can sense the visual image of the car ahead, interpret it correctly, and  
respond to it by sending signals to the muscles that extend the leg  
against the brake? Do you claim that the emotion arises directly from the  
image of the car ahead and is the cause of the amygdala’s response? If  
so, join the ranks of those who accuse me of arm-waving, while madly  
flailing their own around.

I would agree that attention seems drawn to, or seeks out, systems in  
which unusually large error exists. Also, reeorganization seems to be  
focused where attention is. Causality is not clear in all this.

> Bill,  
> you mention that you notice that your muscles become tense when the  
> traffic is heavy.

I proposed that they may become tense as a way of increasing loop gain,  
since the stiffness of active muscle is greater than that of flaccid  
muscle (the force-stretch curve is in fact exponential). I definitely  
don’t think that heavy traffic causes my muscles to become tense.  
Higher-level control systems do.

> Isn  
> t this because you are afraid that the chances of an accident are higher  
> and that you don t want to be in an accident with all that  
> implies?

I doubt that cognitive reasoning comes into it except on a very slow time  
scale prior to any emergencies and after the fact as we attempt to  
explain our behavior when the emergency is over. I would guess that when  
errors start to get larger as traffic density increases , higher systems  
experience somewhat greater errors and raise the gain (perhaps by using  
the amygdala if it is connected in a way that makes that feasible) to  
limit the errors (proximity errors, in traffic). There are other ways of  
increasing loop gain which are probably also used (see above). The gain  
increase could simply be a consequence of an increased error signal  
entering a nonlinear output function.

> Might  
> not this be a case where the Observer enters the  
> picture?

I think the Observer is always in the picture except perhaps when you’re  
unconscious. It’s not clear to me that the Observer and attention are  
necessarily the same thing, especially when attention is measured by such  
things as direction of gaze. Sitting in a movie with your girlfriend,  
your eyes are on the screen but your attention may well be on the  
girl.

> Yes,  
> I want to get to the meeting on time. Yes, I want to advance my career.
> 
> But my life is more important  
> than all of that.
> 
> No conflict, I put my foot on  
> the brake.
> 
> I will be late, but I live to  
> fight another day.

By that time, your front bumper is embedded in the trunk of the car  
ahead. I think all these considerations are better conceived of as  
simultaneous control processes, not a series of steps in after-the-fact  
verbal reasoning. You are proceeding toward the meeting, or work. You are  
furthering your career. You are making a living. You are avoiding  
dangers. These are all perceptual consequences of whatever varying mix of  
actions you’re carrying out at the moment. Error signals of some size  
exist in all these systems at the same time, and contribute to the  
settings of reference signals at the next lower order, whatever that may  
be for the system in question.

One of the lower systems, it stands to reason, is concerned with  
collision avoidance. The reference level for minimum acceptable distance  
may be set by a higher system, and may vary with traffic density (but  
because of the resulting proximity errors, not because of the traffic  
density “stimulus”). Given the reference setting, the actions  
involved in collision avoidance depend only on the error in the system  
controlling perceived distance. If the distance is too small, the  
collision avoidance system will start applying the brakes, with a speed  
depending on the amount of error. This will not cause any appreciable  
change in the error signal at the level of “get to the meeting on  
time,” because the higher variable (say, estimated time of arrival)  
will not change much, percentagewise, on a time scale of a few seconds.  
The speed at which you’re driving is already a compromise among several  
different control systems. Neither a few seconds of braking or a few  
seconds of accelerating will change it much on the time scale, and the  
perceptual scale, of the higher system. So an episode of sudden braking  
to avoid a collision will be followed by an acceleration back to an  
acceptable speed, and perhaps by a higher-order decision to terminate the  
cell-phone conversation to keep your gaze on the road and your free hand  
on the steering wheel instead of gesturing to emphasize a point. This  
episode will have only a minor effect on the perceived time of arrival,  
and will be finished much too quickly for the ETA system to affect it  
while it’s in progress.

That’s my story, and I maintain that it hangs together better, and  
involves a whole lot LESS arm-waving, than the other story, though I will  
admit to extending a hand once in a while – just to steady myself, you  
understand.

You’re a clinical psychologist: see if you can guess what else I might be  
restraining myself from saying.

Best,

Bill P.

---

<div class="post-metadata">

**Author:** ![Richard\_Marken2](http://discourse.iapct.org/letter_avatar_proxy/v4/letter/r/edb3f5/32.png) [@Richard\_Marken2](http://discourse.iapct.org/u/Richard_Marken2)\
**Post date:** [June 30, 2003, 2:34pm UTC](http://discourse.iapct.org/t/ruminations-on-importance/10094/36 "2003-06-30T14:34:49Z")

</div>

[From Rick Marken (2003.06.30.1030)]

> Bruce Gregory (2003.0630.0934)--
> 
> \> Rick Marken (2003.06.29.1610)
> 
> \> Why is your attention free to wander when control gain is low but not  
> \> when it is high? This conclusion must be based on some mechanism you  
> \> are thinking of. What is it?
> 
> Since HPCT does not model attention, consciousness, or emotions, no  
> answer I could provide would pass muster.

I wasn't asking for the PCT answer. I was asking for \_your\_ answer. You said that  
when system gain is low attention is free to wander. What is the mechanism that  
makes this work?

> I don't consider these  
> omissions to be a "fault" of HPCT, but simply a limitation of the  
> model.

But HPCT does model attention, consciousness and emotions. It certainly models  
these things as well as any other theory I know of. Is there some theory you know  
that provides a better model of attention, consciousness, and emotions than does  
PCT? If so, why don't we discuss that theory are and see how it does with the  
data as compared to PCT? That would be so much more attractive than your  
persistent ragging on PCT.

> \> How does the limbic system do it? An explanation of a phenomenon (like  
> \> increased gain and attention when you are following closely in dense  
> \> traffic, assuming that that is a phenomenon) requires more than saying  
> \> that it s handled by a particular part of the brain.
> 
> It seems to me that a skilled fellow such as yourself could provide a  
> simple control model.

OK. It looks like you get far more satisfaction from arrogantly bashing the  
scientific work of others than from doing any scientific work yourself. Enjoy.

Best

Rick

> **···**
>
> ---  
> Richard S. Marken, Ph.D.  
> Senior Behavioral Scientist  
> The RAND Corporation  
> PO Box 2138  
> 1700 Main Street  
> Santa Monica, CA 90407-2138  
> Tel: 310-393-0411 x7971  
> Fax: 310-451-7018  
> E-mail: rmarken@rand.org

---

<div class="post-metadata">

**Author:** ![Bruce\_Gregory4](http://discourse.iapct.org/letter_avatar_proxy/v4/letter/b/7feea3/32.png) [@Bruce\_Gregory4](http://discourse.iapct.org/u/Bruce_Gregory4)\
**Post date:** [June 30, 2003, 3:10pm UTC](http://discourse.iapct.org/t/ruminations-on-importance/10094/37 "2003-06-30T15:10:20Z")

</div>

from Bruce Gregory (2003.0630.1109)]

Bill Powers (2003.05.30.0637 MDT)]

Do you agree on this sequence, or do you, too, claim that the amygdala can sense the visual image of the car ahead, interpret it correctly, and respond to it by sending signals to the muscles that extend the leg against the brake? Do you claim that the emotion arises directly from the image of the car ahead and is the cause of the amygdala's response? If so, join the ranks of those who accuse me of arm-waving, while madly flailing their own around.

This paragraph is very helpful to me. It tells me that you have not the slightest clue as to the current state of understanding of the wiring of the limbic system and not the slightest interest in remedying that lack of knowledge. You are, and apparently always will be, an engineer. There's no disgrace in that, but don't be too surprised when the rest of the world is not as enamored of the engineering of the 1960's as you are.

---

<div class="post-metadata">

**Author:** ![Richard\_Marken2](http://discourse.iapct.org/letter_avatar_proxy/v4/letter/r/edb3f5/32.png) [@Richard\_Marken2](http://discourse.iapct.org/u/Richard_Marken2)\
**Post date:** [June 30, 2003, 3:40pm UTC](http://discourse.iapct.org/t/ruminations-on-importance/10094/38 "2003-06-30T15:40:20Z")

</div>

[From Rick Marken (2003.06.30.1140)]

> Bruce Gregory 92003.0630.1329)
> 
> I'm willing to be corrected. Would you be willing to post a listing of  
> the PCT based papers published during the past five years that contain  
> experimental data and the results of numerical modeling?

I think that would be a worthwhile endeavor. I don't have time to do a thorough  
job now. But I think a lot of those papers are referenced in my "Looking at  
behavior through control theory glasses" paper which was published in 2002 (  
Review of General Psychology,Vol. 6, No. 3, 260-270). Check out the internet  
references, too. There is Marken, R. S. (2001). Controlled variables: Psychology  
as the center fielder views it. American Journal of Psychology, 114(2), 259-282.  
And Powers, W. T. (1999). A model of kinesthetically and visually controlled arm  
movement. International Journal of Human-Computer Studies, 50 (6), 463-58. There  
is also Bill's paper on the inverted pendulum and my forthcoming article on  
prescribing error in \_Ergonomics\_. Jeff Vancouver has a couple good papers out on  
organizational models and there are excellent modeling papers by Richard Kennaway  
and Wolfgang Zocher in the now defunct JPCT. I'm sure there is more I haven't  
mentioned but the stuff is out there. There's not much, I agree, but there aren't  
many people doing the research.

> My point is not that papers written a decade or more ago are not valid.  
> It is that very few papers have been written in the past decade.

Your point was that that somehow invalidates PCT. The fact is that quite a bit of  
PCT-based research and modeling has been done by a very small number of people who  
often don't even bother trying to publish anymore. The PCT work that is in the  
literature is of very high quality and is of as valuable now as when it was  
published. Unlike most other work done in the social sciences, PCT's merits are  
not judged by whether it is the currently hot, trendy theory. PCT was the best  
behavior theory going in 1961 and it's the best one in 2003.

> \>\> The oft-cited spreadsheet  
> \>\> simulation demonstrates that certain hierarchical models are not  
> \>\> unstable. Nothing more. Nothing less.  
> \>  
> \> I think it demonstrates quite a bit more. It certainly demonstrates  
> \> some of the mportant principles of hierarchical control hat are  
> \> part of the HPCT model:
> 
> In order to understand the working of the spreadsheet one must study  
> the details of how the simulation is constructed (the formulas in each  
> cell of the spreadsheet). Simply running the demonstration and varying  
> the parameters demonstrates whether the selected parameters lead to a  
> stable system output.

Of course!! You can't learning PCT by just looking at the behavior of the  
spreadsheet any more than you can learn physics by looking at an animation of an  
object falling according to Newton's laws.

> By the way, what would it mean for their to be  
> conflict between different levels of the hierarchy? My admittedly  
> limited understanding is that conflict only occurs when two higher  
> levels in the hierarchy are trying to set different reference levels  
> for a common lower level system.

Conflict occurs when two systems at the same level in the hierarchy (two systems  
controlling the same types of perceptual variables) are controlling non-orthogonal  
(mathematically equivalent) perceptual variables relative to different  
references. Conflict is a perceptual, not an output, phenomenon. Conflict exists  
when two control systems act to keep what is virtually the same perceptual  
variable in two different states. In order to do this, the two systems are  
\_usually\_ (depending on disturbances) trying to get the same output into two  
different states. But this is not what defines the conflict. In a hierarchical  
system, higher level systems are almost always trying to get the same lower level  
outputs into different states (in the sense that the reference for the lower level  
systems is the sum of the outputs of several higher level systems).

Best regards

Rick

> **···**
>
> --  
> Richard S. Marken, Ph.D.  
> Senior Behavioral Scientist  
> The RAND Corporation  
> PO Box 2138  
> 1700 Main Street  
> Santa Monica, CA 90407-2138  
> Tel: 310-393-0411 x7971  
> Fax: 310-451-7018  
> E-mail: rmarken@rand.org

---

<div class="post-metadata">

**Author:** ![Bruce\_Gregory4](http://discourse.iapct.org/letter_avatar_proxy/v4/letter/b/7feea3/32.png) [@Bruce\_Gregory4](http://discourse.iapct.org/u/Bruce_Gregory4)\
**Post date:** [June 30, 2003, 4:37pm UTC](http://discourse.iapct.org/t/ruminations-on-importance/10094/39 "2003-06-30T16:37:50Z")

</div>

[From Bruce Gregory (2003.0630.1237)]

Rick Marken (2003.06.30.0910)

I am surprised at you David. Bruce is not bringing up interesting issues. He is simply attacking PCT by asserting the existence of weaknesses in the theory that don't exist.

The only interesting issue Bruce brings up, as an accidental side effect of his superficial attacks, is why PCT engenders such hostility.

Nice demonstration of paranoid thinking. But even paranoids have enemies, right? I told you, my hostility to PCT is the result of an unresolved Oedipal complex. I identify you with my father and Bill with my mother. You can take it from there, can't you?

---

<div class="post-metadata">

**Author:** ![Bruce\_Gregory4](http://discourse.iapct.org/letter_avatar_proxy/v4/letter/b/7feea3/32.png) [@Bruce\_Gregory4](http://discourse.iapct.org/u/Bruce_Gregory4)\
**Post date:** [June 30, 2003, 5:30pm UTC](http://discourse.iapct.org/t/ruminations-on-importance/10094/40 "2003-06-30T17:30:36Z")

</div>

[From Bruce Gregory 92003.0630.1329)]

> Rick Marken (2003.06.30.0940)]
> 
> > No data (except the notoriously suspect 'introspection') and no  
> > quantitative models.
> 
> Saying such things doesn't make them true. Why are you doing this?

I'm willing to be corrected. Would you be willing to post a listing of  
the PCT based papers published during the past five years that contain  
experimental data and the results of numerical modeling?

> > I assume that you agree since you keep pointing to  
> > same few papers written a decade or more ago.
> 
> Of course I don't agree. Those papers contain data and quantitative  
> models that  
> are ust as valuable today as they were when first reported. Why are  
> you doing  
> this?

My point is not that papers written a decade or more ago are not valid.  
It is that very few papers have been written in the past decade. The  
bibliography I asked you to post will show whether I have misstated the  
case. If so, I will promptly apologize.

> > The oft-cited spreadsheet  
> > simulation demonstrates that certain hierarchical models are not  
> > unstable. Nothing more. Nothing less.
> 
> I think it demonstrates quite a bit more. It certainly demonstrates  
> some of the  
> important principles of hierarchical control that are part of the HPCT  
> model:  
> control of several higher level perceptions simultaneously without  
> conflict using  
> the same set of lower level control systems, lack of conflict between  
> systems at  
> different levels of the hierarchy, higher levels controlling  
> perceptions that are  
> a function of perceptions controlled at lower levels, etc.

In order to understand the working of the spreadsheet one must study  
the details of how the simulation is constructed (the formulas in each  
cell of the spreadsheet). Simply running the demonstration and varying  
the parameters demonstrates whether the selected parameters lead to a  
stable system output. By the way, what would it mean for their to be  
conflict between different levels of the hierarchy? My admittedly  
limited understanding is that conflict only occurs when two higher  
levels in the hierarchy are trying to set different reference levels  
for a common lower level system.

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