Hi Bruce
RM: The PCT model of program control has nothing to do with the information processing model of cognition. In PCT, programs are perceptual inputs;
BN: In the information-processing model, programs calculate outputs. Those outputs are inputs to the system at the level above which invoked the program. In your demo, a system above programs recognizes that perception as the output of the given program, or not.
RM: This makes no sense. I agree that the information processing model calculates program outputs. But those outputs are not inputs to the system in either information processing models or PCT models. Information processing models of program production are open-loop so the inputs know nothing about what the outputs are doing. In PCT models of program control, what goes into the input is the combined effect of outputs and disturbances.
RM: In my demo, what is shown is that a person can control the perception of a program. In order to model that behavior I would have to be able to build an input function that recognizes that a particular program is occuring. That program recognizing function would be in the system that is controlling the program, not in the system above it.
RM: …what is carried out is a program: a network of contingencies. In PCT, program control involves controlling for a perception of a particular program (network of contingencies) being carried out, regardless of how that program is being produced.
BN: No, the level above programs controls a perception of a given program being carried out. The carrying-out of the program is done on the program level. Or where did you think the carrying-out of the program was done?
RM: In my demo, the carrying out of the program is done by the computer in combination with the output of the person. The program that is seen on the display is a disturbance that is combined with the controller’s output (the bar press). There are many real world examples of situations where a program is controlled in much the same way as it is in my demo. For example, a basketball coach might be controlling for his team running a program called man-to-man defense. When he sees the team falling into what looks more like a zone defense he might shout something to try to get the team to “get with the program”.
RM: Even when a person carries out a program themselves their outputs (muscle forces) are not necessarily correlated with the program they intend to produce (the controlled result) because these outputs will be countering disturbances to lower level controlled variables. For example, when you are driving somewhere following the program of stopping at red and going on green, you will be producing different outputs at each contingent point in the program since at some intersections you have to vary your braking or accelerating depending on your speed of approach to the red or green light.
RM: Remember, in PCT, it’s not outputs that are controlled, it’s the perceptual consequences of outputs that are controlled. Behavior is the control of perception.
RM: Since Bill Powers did his original work with analog computers I think he was very familiar with the difference between analog and digital computing.
BN: Yes, indeed. But he explicitly abandoned analog computing above the Relationship level, because he didn’t know how to incorporate language into the model. He lays it out clearly in his 1979 paper on which the topic “Powers’ Model of a PCT-Based Research Program” is founded. For convenience, I provide here an extended quotation beginning on page 198.
- Categories. This level did not appear in my 1973 book, and it may not survive much beyond this appearance. The only reason for its introduction on a trial basis is to account for the transition between what seems to be direct, silent control of perceptions to a mode of control involving symbolic processes (level 8).
RM : There is no abandonment of analog processing here. The model is still based on the idea that the system consists of continuously varying neural signals. The inputs to and outputs from the proposed category control level are continuous (analog) variables. The output of a category perceptual function is a neural firing rate that is a measure of the degree to which an instance of the category is present: it’s “dogness” or “ponyness”, for example.
BN: Bill’s only reason for introducing a Category level is to explain words as symbols and programs as the manipulation of symbols. This is a shallow and frankly naive conception of language as denotation, as I said to him in the 1990s
and as I have demonstrated many times in many forms. He did not know how to take it further, he asked me to do so, and I continue with that project.
RM: Well I"m glad you’re on the case;-)
BN: Notice his recognition that categories are no more than complex relationships. I have argued this for years, forgetting that he said the same in this essay (one of the earliest that I read after B:CP).
RM: What I notice was Bill trying out various hypotheses about the types of variables controlled at different levels, hypotheses that he hoped to see tested in a PCT-based research program. You don’t test hypotheses with arguments; you test them with experiments!
BN: A month ago, Warren passed along this question from an interested person:
do you have any resources on how PCT handles, e.g. symbolic manipulations in the consciousness (mental mathematics, for example)?
BN: I quickly put together a summary as follows:
Language.
Mental mathematics is a telling over in words of the mathematical terms and operations…
Meanings are imputed in in the same way to constructions of words including phrases, clauses, incomplete sentences, sentences, discourses, sets of discourses constituting sublanguages, etc.
BN: I imagine that your eyes glaze over as you look at this.
RM: My eyes glaze over at nearly everything these days.
BN: Repeating from Bill’s essay:
Perhaps it is best merely to say that this level works the way a computer program works and not worry too much about how perception, comparison, reference signals, and error signals get into the act. I think that there are control systems at this level, but that they are constructed as a computer program is constructed, not as a servomechanism is wired.
BN: This is Bill’s leap of faith onto the computational metaphor.
RM: Well, he did say that control systems are involved. In other words, program control is control of perception of programs. I think the non-servo aspect of their construction is in how they produce the programmatic references for lower level systems (when they do need to produce that kind of output).
RM: I think all Bill is saying is that we don’t know how to build systems that control program perceptions. But my demo (and some demos that Bill suggested, on which my demo is based) demonstrates that we do control program perceptions.
BN: After all that work on introspective phenomenological investigation into the lower levels, he threw up his hands and fell into the same conceptual ‘local minimum’ as everyone else. A combination of introspective phenomenological investigation and neuroscience will show what the brain is really doing.
RM: He did throw up his hands when he tried to think about HOW program control works. But he was right about the fact THAT programs are controlled variables.
BN: Another bit of the quotation repeated:
building workable digital computers has informed us of the operations needed to carry out the processes human beings perform naturally–perhaps not the only way such processes could be carried out, but certainly one way.
BN: No, digital computers show us a way to emulate those particular aspects of thinking and problem solving that logicians have formalized.
RM: I think that is what Bill meant when he said that “perhaps [digital computer programs] are not the only way such processes can be carried out”.
BN: Humans notoriously are not always logical in their thinking and problem solving…
RM: And even when they are logical in their thinking they are not necessarily right. Bill knew this, of course, which is why he was a strong proponent of the scientific method, where theoretical explanations of phenomena, no matter how logically they have been derived, are not considered correct until their predictions are tested against observation. And even then, if they pass the test they are still only considered tentatively correct. Just more correct than any other current explanations.
RM: Your criticisms of Bill’s explanations of program control could be moved back into my PCT-based research program thread if you could provide some convincing empirical tests that prove that those explanations are wrong. And, even better, provide some empirical tests to show that your explanation of program control is more correct.
Best
Rick