[From Bill Powers (2009.12.22.0730 MDT)]
BH: The most important thing I see till now is that we established the existance of feedforward and that combination with feed-back exists.
BP: As your citations show, I have never claimed that prediction and "feedforward" don't exist. I posted a diagram showing how they would work together in the same system.
Before any feedback effects could have existed (at the start of evolution), there must have been effects of environmental stimuli on the interaction of proto-organisms with their environments (ordinary causation). When negative feedback arose, however, it would quickly have replaced feedforward or S-R relationships, leaving them to be important only when feedback control is impossible. And saying "important" is not the same as saying that feedforward would work very well. Feedforward can't deal with any changes in the output functions of a system, or changes in the properties of the world being acted upon, or occurrance of disturbances of kinds that can be detected only through their effects on a critical variable.
BH: But I don't see that as a problem. A problem I see is not whether people's or animal's behavior has more feedforward or more feedback, or what is more important or efficiant. The problem I see is why it spontaneously occurs "switching", when control is impossible as Bill said, and why this mechanism was "developed" through evolution if it is so unusefull and should be replced by feedback as PCT predicts?
BP: My guess is that it wasn't "developed" through evolution, but was there from the start, and can also result from reorganization. Disturbances of proto-organisms (organic molecules) altered the interactions with the environment according to physical and chemical laws. They still do. Effects of that kind that reduce the chances of continued existence eliminate that line of development: that is natural selection. The entities that remain are those which don't react, or react less, to external influences in ways that reduce their chances of surviving. That process of elimination is random, slow, and inefficient. But over a billion years, it works. It also works in a single lifetime as we become organized.
When negative feedback was developed through natural selection, there must have been an enormous increase in efficiency: negative feedback control will replace feedforward everywhere that is possible.
BH: I hope we are not talking about how behavior will suit the most to theory of PCT, but how theory of PCT will succesfuly explain what is really happening in the behavior and why we make so many mistakes in the game and in life. Probably because we don't control actual perceptions all the time. So I'm asking myself why people are using that "alternative mechanism" in behavior if it's not so efficiant as control is or is maybe effeciant only in
combination with control.
BP: My guess is that we use feedforward when there is no way to get immediate and accurate feedback about the state of whatever we're controlling (or when the effort to do so isn't worth the trouble because it's not an important variable). But "mistakes in the game of life" are a different matter. Even if we're controlling a variable, we may not pick a good variable to control -- think of people who want to make billions of dollars, and do it, and are laughed at or hated by everyone instead of being admired. It doesn't help them to be control systems.
BH: I never tried to say that Bill is not a great inventor and even less that
PCT is not a great theory. But I'll always say that nothing could be so good
that it couldn't be better. If we'll try to fit all behaviors into PCT, it
will never advance. And I think this is also the case with feedforward. Why
not trying to explain why feedforward occurs in HPCT and use it as something
that has the best explanation in PCT.
BP: First, it would be good to know exactly what you mean by the term "feedforward." I have my own understanding of it, but perhaps you see something there that I don't see. Some examples would be useful. I have described one (the fielder running to where the ball will be without looking at the ball) and have noted that in my limited experience with watching outfielders on television, this method doesn't appear to work very well. It's used mostly when the more reliable method, watching the ball all the time, can't be used. Also, I've commented on a related problem: collision avoidance. It is possible to predict where another ship is going to be, and where your own ship will be at various future times, and decide in this way whether both ships will arrive at the same place at the same time. But it is far easier simply to take repeated bearings on the other ship. If the bearing (the angle relative to your own ship's direction) is constant, and the distance to the other ship is decreasing, there will be a collision. No need to predict specific future positions at all. If you control to keep the bearing changing, you will avoid the collision. It's just a matter of controlling the right present-time variable.
What kinds of examples are you thinking of?
BH: People observe and obviously common experiances show that there is something "strange" happening. Now I think we have to explain that. Just answer, it's not good to use feedforward, it's better that we use control, because it's the most effective, will not help much.
BP: What's strange about feedforward? It's just a blind reaction to a sudden change. You can organize yourself that way if you want to; there's no law against it. A small child sees a fire and reaches out toward it, perhaps "instinctively." But not more than once. We all quickly learn the advantages of feedback control, and fortunately evolution has provided the necessary equipment to acquire control systems.
BH: So I don't see the problem in question whether closed loop is the best to
use or not. I'm asking myself why people use feed-forward so much if it's
not neccesary in some situations or even something what result with bad
consequences ?
BP: Since there's no instruction book, each of us has to learn through experience what variables we need to control, and how to control them. No two of us experience identical environments, but we learn to control anyway, because we can reorganize. I don't think people use feedforward very often, compared with the number of situations in which they use feedback. But people do use feedforward, which proves that reorganization can produce that result just as it can produce control systems. But usually feedforward leaves enough error so reorganization will continue, leading to the development of a control system instead. It's possible that the result will be a combination of feedforward and feedback, but in my experience that's not usually needed.
I actually tried using some feedforward in a tracking task, displaying a representation of the disturbance that was affecting the cursor (normally, the disturbing variable can't be sensed in my tracking tasks). I wanted to see if it would improve control. The result was to make control worse, because attention was taken away from the target movements. So that wasn't a good way to introduce feedforward. A better way would be to make it internal to the subject, connecting a perception of the moving target directly to the circuits that operate the muscles. But the feedback model we use already accounts for more than 99% of the variance of the behavior, so adding feedforward couldn't improve control by a large amount. Maybe a little bit.
BH: I agree with Bill that the best way to play is to be all the time in control mode. That's why coaches yell. But goals of players which unexpectadly occurs during the game differs from those in coaches minds, because they are not experiencing the playing situation.
BP: Well, coaches don't yell at players who catch the ball every time, so if feedforward works as well as feedback, I'm sure the coaches would permit it unless they like losing games.
BH: The question for me was always why I can't do "what's right" in the critical situation, and I ussually always realized after, that I made a mistake and that it would be better if I've done as coach said. But in "that moment" I just "couldn't remember", although I've heard that hundred times on
trainings and games.
BP: Hearing and doing are two different things. I had a football coach who would yell "Put your back into it." I could never figure out how to do that.
BH: So I think that we must explain why feedforward is happening during the game even to players (professionales) who train 4,5,6 and even more hours a day just for not doing that mistakes. But they still do. They fail to catch the ball, they fail to receive pack, they fail to receive ball, they fail to
switch over on right place, they fail to score from 2-meters from goal and
40.000 or more spectators think "what an idiot", even I could score that
ball. Well I'd like to see them in that situation.
BP: What you're saying, if I understand you, is that in the actual situation, either you can't remember what you're supposed to do, or the behavior you've been told to use wouldn't work. Of course if you're supposed to react to a particular situation automatically by doing a particular behavior, that is already feedforward or stimulus-response, so you're describing a choice between two feedforward strategies, the one you automatically use and the one you're told to use. Maybe a control process would be better than either one. Good coaching tells you what variables to control, not what behaviors to carry out. But not many coaches know that, apparently.
BH: So I'm asking myself all the time why feed-forward exists in behavior and
why organisms use it probably spontaneuos or why evolution "develope" that
mechanism and kept it in living organisms if it's not so usefull or even
neccesary for behavior ? Maybe it's some kind of mechanism in control
systems that occurs automatically ?
BP: I think it might be just a control system at the sequence level: if event or situation A occurs, the next thing must be behavior B. If we're predisposed to develop control systems, that's one way we can imitate a stimulus-response system. Tom Bourbon wrote a paper about that -- the way a control hierarchy can imitate either a stimulus-response system or a top-down cognitive system. [If anyone has a copy, you might post it]
BH: So I'm asking myself if we could turn this conversation into advantage for PCT and explain why the combination of feedforward and feedback occurs and how to use it the training to make players more efficiant and finally to win the game. That could by my oppinion make PCT usefull aplication. "Guessing" what is better won't do any advance.
BP: Right. The best thing to do is to stop arguing and get out on the playing field and test your ideas. I always do that if it's possible. Either that or try to devise a working simulation to test the idea. I don't take abstract arguments very seriously.
BH: I've heard some good theoretical back-ground for feed-forward and it seems to me quite exceptable from PCT view, but I must ask the member of CSG net if we can introduce our conversation. I respect the intimacy if others do. But if they don't, I don't either.
BP: You don't have to ask anyone's permission to introduce a new topic. The worst that can happen is that if nobody is interested in it, nobody will comment.
Best,
Bill P.
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At 10:46 AM 12/19/2009 -0600, Boris Hartman wrote: