Good idea.
The identity of qi and p is defined by the formula that defines them. If qi and p are the area of the rectangle then both are defined as h * w; if qi and p are the perimeter of the rectangle then both are defined as 2*(h + w). What’s confusing you (and clearly you are not alone in your confusion!) is the fact that qi has identity (for example, you know what the area of the rectangle “looks like”) while p is (in theory) a neural signal that varies only in magnitude; it seems to have no identity.
But in PCT p does have an identity and it is defined by the perceptual function that produced it. The magnitude of p is an analog of variations in the perceptual variable that is defined by the perceptual function. When you are controlling the area of the rectangle, you define qi as h * w and, in theory, the perceptual function defines p as h * w.
But, you say, p doesn’t “look like” qi, so how can I say that p = qi? One is a neural signal and the other is a pattern of light out there in the world? I’ll try to explain it in terms of an inanimate control system, the cruise control system in your car. This system has a perceptual function that converts the rotation of the wheels of your car into an electrical signal, p.v, which is a perception of velocity. The perceptual function is:
p.v = 2 * pi * r *f
where pi is 3.14159, r is the wheel radius and f is wheel revolutions per second. So p.v is an electrical analog of velocity in units of distance/duration making p.v is an electrical (perceptual) analog of the controlled variable, qi.v, which happens to be
qi.v = 2 * pi * r *f
So, even in a non-living control system, p = qi.
But perhaps you are still confused because, unlike the cruise control system, you don’t see just electrical signals when you control the area or perimeter of the rectangle. What you are running into here is the “hard problem” of consciousness, the problem being “Why the f**k does the world look like this when I know it’s just electrical signals in my brain”! And I have a not so great answer to that question: That’s the way the world looks when you ARE the neural signals (and perceptual functions) involved in dealing with the ourside world.
But the best way to understand that qi = p in a control system is to do some modeling of control systems. And you might also take a look at “receptive field cells” to get an idea of how perception works, in PCT and in physiology.
Yes, qi is the “objectively observed” controlled variable (objectively observed using some version of the test for the controlled variable) and p is its theoretical counterpart that is used in models of behavior.
[quote=“JohnGraham, post:1, topic:16275, full:true”]
… and then I checked in Tim Carey and Margaret Carey’s RTP Intervention Processes and found this explanation (p120)
A tenet of PCT is that, almost always, the state of particular environmental conditions correlates highly with the state of an individual’s perceptions. So we label environmental conditions that correlate highly with controlled perceptions (p) as controlled variables (cv)
Tim is one of only 3 people who I would tell anyone to go to if they wanted to know what PCT was about. And he is by far the best writer on things PCT. Nevertheless, I judge this to be a rather awkward way of making the distinction between cv (qi) and p. But I think it’s OK as long as “environmental conditions” are understood to be conditions (like the area or perimeter of a rectangle) that are functions of sensory (and, ultimately, environmental) variables.
No, there are just two concepts, CV (or qi) and p. Bill has also used “Controlled Quantity (CQ)” and “Input Variable” for qi and when he used CQ for qi he has used CV for p. Clearly, the distinction between CV and p (whatever you call them) is difficult to communicate, even for the extremely lucid developer of PCT, but it becomes completely non-confusing when you code up a working control system simulation of some control behavior, like tracking.
I never liked the term Controlled Environmental Variable because it implies that what we control are entities in the environment when, in fact, we control functions of environmental variables.
No, qi and CV refer to the same thing; the aspect (or function) of the environment that is controlled. Again, I know that all of this can be difficult but once you do some modeling of control behavior it all becomes perfectly clear. I say this because I struggled with these terminological difficulties until I started to do modeling of actual behavior. It’s the best teacher, at least for would-be scientific psychologists.