# Catching, Question, Model-based control

**URL:** <http://discourse.iapct.org/t/catching-question-model-based-control/2358>\
**Category:** CSG1995\
**Created:** [May 11, 1995, 8:35pm UTC](http://discourse.iapct.org/t/catching-question-model-based-control/2358 "1995-05-11T20:35:18Z")\
**Posts on this page:** 1\
**Page:** 1

<div class="post-metadata">

**Author:** ![Richard\_Marken](http://discourse.iapct.org/letter_avatar_proxy/v4/letter/r/9fc348/32.png) [@Richard\_Marken](http://discourse.iapct.org/u/Richard_Marken)\
**Post date:** [May 11, 1995, 8:35pm UTC](http://discourse.iapct.org/t/catching-question-model-based-control/2358/1 "1995-05-11T20:35:18Z")

</div>

[From Rick Marken (950511.1330)]

John Anderson (950510.1630) --

> Bruce and Rick, here's a paper from the 28 April 1995 issue of Science  
> you might consider:

Sounds like PCT all the way.

> The authors did two kinds of experiments...In the other, they mounted video  
> cameras on the fielders' shoulders, and taped the ball's path relative to  
> the fielder, to see the shape of the ball's trajectory.

This has all the earmarks of PCT research; monitoring two hypothetical  
controlled variable (perceived trajectory or acceleration of the ball) with  
varying disturbances (the balls hit in many directions relative to the  
fielder).

Take me out to the ball game!

Mark George (950510) --

> Our question was, on chapter 10, page 143, section 10.3.1, third paragraph,  
> first sentence "The control-theory. . . are percieved at the . . ."

Dick Robertson (950510.2130CDT) --

> Rick Marken, I hope you picked up this question; it's from your part  
> of the chapter.

I don't have the book with me here at work so I'll answer Mark's question  
when I get home this evening.

But it's nice to hear from you Mark. Have you been listining in on csg-l for  
long? How about the rest of the class? Does Dr. Lansky know about csg-l? It's  
always nice to discover new people who are interested in PCT. Could you  
(or Dr. Lansky) say something on the net about the PCT class?

Bill Leach (950511.00:40) --

> The problem is that at least many of us DO reach for the soap without  
> looking or maybe even without being able to look.

Ok. Ok. Apparently the model-based control thread will not go away so let me  
try to clarify my position -- again.

The most important thing PCT has to offer the life sciences is a view of  
behavior as the control of perception. That basic point has not been easy to  
get across. In fact, except for the occasional baseball freak, there has been  
virtually no research organized around the study of living organisms as  
perceptual control systems.

If the control view of behavior were taken for granted, then I would have no  
problem with the discussion of "model- based" control; some kind of "model-  
based" control is surely involved when you move your hand towards the  
currently invisible soap, for example. If PCT were taken for granted, then  
everyone would know that any kind of model-based control that is involved in  
this behavior is just part of the process of controlling a perception of the  
relationship between hand and soap. But PCT is not taken for granted and  
model- based control often turns out to be a way of making perceptual control  
look like control of output (a good example of this is an article by M.  
Jordan called "Motor learning and the degrees of freedom problem" in M.  
Jeannerod (Ed) Attention and Performance XIII, Erlbaum: 1990).

I think that the best start at a "model-based" control of perception model is  
found in the "Memory" chapter of B:CP. The details of the model were not  
worked out because there were no data; apparently we will start collecting  
the data now.

Best

Rick