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- Posted-Date: Fri, 14 Aug 92 09:49:45 PDT
- Message-ID: <199208141649.AA04005@aerospace.aero.org>
- Newsgroups: bit.listserv.csg-l
- Date: Fri, 14 Aug 1992 09:49:45 PDT
- Sender: "Control Systems Group Network (CSGnet)" <CSG-L@UIUCVMD.BITNET>
- From: marken@AERO.ORG
- Subject: Disturbances
- Lines: 115
-
- [From Rick Marken (920813.1000)]
-
- Dennis Delprato (920813) --
-
- Great to hear from you. I think your ideas about introducing PCT
- to non-PCT psychologists are EXCELLENT.
-
- >Basically, I am suggesting a critical look at the classic
- >experimental framework (CEF), a set of assumptions not questioned by
- >adherents to otherwise divergent theories and approaches. CEF-thinking
- >is taught to all psychologists. It is possibly one of the very few
- >points of general agreement in the fractured field of psychology.
-
- I agree completely. I've always felt that the difference between conventional
- and PCT psychology could be best approached from the point of view of
- methodology (since its the same for all psychologists, regardless of
- theoretical persuasion). I like your suggestion about moving non-PCT
- psychologists gently to the concept of control by showing them how
- they might profitably reconceptualize "extraneous" variables as
- disturbances. I think you might consider taking the lead on this
- approach. Perhaps there are some operant conditioning studies where
- people have felt that the results were a bit too noisy due to these
- extraneous variables? If you could find a study like this then
- perhaps you could show that the "noisiness" of the behavior is the organism's
- efforts to reduce the effect of these variables on a controlled variable.
- In fact, now that I think of it, the concept of a controlled variable
- let's you distinguish between "extraneous variables" that are disturbances
- and extraneous variables that are extraneous. Only variables that have
- an effect on the controlled variable are disturbances -- ie. the kind of
- extraneous variable that will actually influence behavior.
-
- Go with this idea Dennis.
-
- Oded Maler (920814)
-
- >It is also not
- >self-evident at all that a world where all people know what control is
- >will be a better one - but anyway I'm not interested in Ideology
- >(unless I'm in a historical museum).
-
- I agree that it is not self-evident. I can see that my sloganizing is
- coming back to haunt me. What I meant was simply that, if people
- understood that people were control systems, then they would KNOW for
- a FACT that their efforts to control people (in order to "make things
- better") will not work. The reason is simple -- one person's efforts to
- control another are just disturbances, and will be automatically countered
- by the controllee. This is not an ideological point -- but a fact about
- how control systems work.
-
- I have a demo which illustrates this point. It's sort of the inverse of
- my mindreading program. I know it's a good demo because Gary Cziko liked
- it. I call it "find mind". Here's how it works:
-
- There are 5 numbers roaming around the computer screen. The behavior of
- 4 of the numbers is determined by a VERY simple output generation model;
- at each time interval the x,y specification of position is updated and
- the number "moves" to the specified screen position. One of the numbers,
- however, is a control system. The x,y specification at each time interval
- is the value of the REFERENCE SIGNAL. So this system is controlling it's
- perceived x,y position relative to a varying reference. The position of
- ALL FIVE numbers is also influenced by the position of the mouse. If you
- leave the mouse alone, this just means that a constant is being added to
- the x,y position of all 5 numbers. When you look at the screen what you
- see are five numbers drifting around, each taking a different path (determined
- by the particular waveform that determines its x,y coordinates (or reference
- signal)). There is NO WAY to tell, by looking at their behavior, which of
- the 5 numbers is a control system and which are "output generators". The
- appearance of the behavior of all 5 numbers is EXACTLY the same.
-
- But you can very quickly tell which of the 5 numbers is a control system
- if you introduce a disturbance by moving the mouse. If you move the mouse
- abruptly, you will see all 5 numbers shift in the direction of mouse movement,
- but one number will "bounce back" to its intended path. This bounce is easy to
- see, even though you don't really know where the number intends to move.
- So the control system "responds" to the mouse disturbance in a very obvious
- way; the rest of the numbers show no such bounce -- they just shift their
- movement to the "offset" caused by the mouse disturbance. The behavior of
- the control system number is like a "reflex" -- such as the behavior of the
- pupil when you suddenly shine a light in the eye.
-
- If you apply the disturbance more smoothly then you cannot see it's
- differential effect on the "control system" number. If you just move
- the mouse around slowly and aimlessly you will not be able to tell, again,
- which of the numbers is "alive". But you will quickly learn which number is
- alive when you try to hold a number at some target position on the screen --
- ie. if you try to control the position of a number. If you try to control
- one of the "output generation" numbers then there is no problem -- you
- can easily move the mouse appropriately to compensate for the changing
- x,y position of the number. But if you happen to pick the control system
- number, then you find that your mouse movements become much more exaggerated.
- It turns out that the control system is generating outputs to prevent your
- disturbance (mouse movements) from moving it from its intended path. Your
- efforts to get that number to stay on target are, in fact, placing you in
- a conflict with that number. Since I have placed no limit on the amount of
- output that the control system number can generate, the control system will
- win the conflict (you will run out of disturbance -- mouse -- first). Some-
- times, this is the way things work out in real life (like when you try to
- control little kids) -- but, as I said, not for long, since control systems
- don't give up.
-
- This little demo illustrates my basic point -- if people are control systems
- then efforts to control them just create conflict; and conflict is not
- good for either party because it involves loss of control.
-
- Best regards
-
- Rick
-
- **************************************************************
-
- Richard S. Marken USMail: 10459 Holman Ave
- The Aerospace Corporation Los Angeles, CA 90024
- E-mail: marken@aero.org
- (310) 336-6214 (day)
- (310) 474-0313 (evening)
-