Control System Description (was Control in a Company)

[From Fred Nickols (2009.04.26.0804 MST)]

[From Bill Powers (2009.04.26.0645 MDT)]


Here's a little test, just to see if you understand the principles or
just know the words: Describe correctly, clearly, and simply how a
control system works without using the words input, variable, signal,
perception, compare, error, reference, output, feedback, or control.
If you can do that, you can claim to understand PCT. I'll give you
two weeks to work it out.

Come on, folks, let's see you try it. I don't offer any reward except
what you get from doing it. But if you don't, I'll punish you by
taking away your garbage.

Here's my shot at it...

We, as people, always want or need something. There are many things we want or need and often we want or need these at the same time. It is also the case that what we want changes over time and is or can be different under different circumstances. In other words, we have goals and these goals vary. In most cases, our goals pertain to some aspect of the world around us, to some element of it that we target and which we want or need to be in a particular state or condition. To achieve our goals, we act; more specifically we act on various aspects of the world around us � usually thoose targeted elements (although not always directly). These targeted elements often include other people (who are also acting to get what they want or need).
Thanks to our five senses, we are informed as to the state of the world about us, including those targeted elements, and thus we can tell if our goals are being or have been achieved. If a goal has been achieved, no further action is required to achieve it (although additional action might be required to keep the want or need in question satisfied).

If that were all there is to it, life would be great. We would simply go about doing whatever we have to get whatever it is we want or need and all our wants and needs would be satisfied. To some extent, that is the case. We human beings are pretty good at getting what we want and doing so has high survival value. However, there are other actors and factors at work and these other actors and factors can and often do interfere with our ability to achieve our goals. When these interferences are minor, no more than nuisance factors, we hardly notice them; we simply adjust and adapt and go on our merry way without giving the matter much if any thought. Even if the interfering factors are significant, we can still adjust and adapt and still achieve our goals. But, on occasion, these interfering factors overwhelm our flexibility and we cannot compensate for or offset them. We fail to achieve our goals.

Let’s say I’m feeling thirsty. I go to the refrigerator to get a bottle of cold water. But there are no more bottles of cold water in the refrigerator. Maybe I simply take a drink of tap water. Or perhaps I run to the store and get some more bottled water. Or maybe I drink some coffee instead. In any case, I satisfy my thirst. I am no longer feeling thirsty. I want or need something; I act to get it; and I adjust and adapt what I do to accommodate any interfering factors. If someone sets me down in the middle of the Sahara Desert, I've got a different problem on my hands.

I don’t set a goal of being thirsty. My body tells me I am thirsty and I set a goal of getting some water so as to satisfy that thirst. Wants and needs, then, exist at different levels. Some are basically biological, such as thirst, and some are more consciously formulated (e.g., wanting water so as to satisfy thirst). In short, wants and needs and goals exist at different levels. Picture now many levels of wants and needs and goals in a person, many of which are related to one another and all of which have to be achieved by that one person. Complicated, isn't it?

To recap, people have goals that reflect wants or needs ranging from simple biological necessity to ego-satisfaction. Goals specify the condition that some targeted element in the environment must satisfy. People are capable of acting and they act so as to achieve their goals. Their actions affect those targeted elements in their environment and observed changes in these elements inform them as to the current state of that targeted element in relation to their goal state for that element. They continue to act until their observations indicate the goal has been achieved. Other actors and factors in the environment can interfere with their ability to bring a targeted element to some specified state but, unless they are overwhelming, people can adjust and adapt and still achieve their goals. Indeed, people often have goals related to neutralizing factors that interfere with their attainment of other goals. In the end, successful goal attainment is defined as the extent to which observations of targeted elements are aligned with the goal state for that element.



Fred Nickols
Managing Partner
Distance Consulting, LLC

"Assistance at A Distance"

[From Bill Powers (2009.04.27.0700 MDT)]

Two inches of snow on the ground this morning.

Fred Nickols (2009.04.26.0804 MST)]

Fred, I'm going to save the contributions to this thread for a while and will comment on all of them later.

Since this isn't a competition, others may benefit from a few preliminary points. You may want another hack at it, too.

One of the things PCT does is define terms in a way that's as unambiguous as possible. Your essay does a lot of this in terms of a person's own experiences, but it still relies on some key terms that are used without any definitions. Want, need, goal, acting, achieving or satisfying (a goal), adjust and adapt. I'm sure you can pick out more if you read with that idea in mind.

Try to make this an essay that explains how organisms, human or otherwise, work -- but for a person with absolutely no technical or psychological background: the Man from Mars. The challenge is to get it technically right, but strictly in terms of experiences a person without technical training might have. I don't mean going to extremes here: just trying to avoid assuming that the reader understands the critical words, which you can select yourself.


Bill P.

[David Goldstein (2009.04.27.18:00 EDT)]

Here is something I wrote. It was inpired by observing my one year old
granddaughter, Lilah, trying to eat with a spoon.
It was also inspired by my Friday lunch with Dr. David London, a colleague,
as I tried to explain the concept of control.

Here is an example of a person controlling the experience of eating food.doc (30 KB)

[From Rick Marken (2009.04.27.2100)]

David Goldstein (2009.04.27.18:00 EDT)–

Here is something I wrote…

Gosh, David, that was really nice, and so damn close. But, alas, you used the forbidden word “control”. If it’s any consolation, I fell into the same trap (yep, I used the word “control” about 4 words into my essay) so I decided to give it up and play Let’s Make a Deal instead;-)

Best regards



Richard S. Marken PhD