Measuring Input-Output Characteristics of Components of a Closed Loop: Redux

[From Bruce Abbott (2014.03.14.1505 EDT)]

···

From: Control Systems Group Network (CSGnet) [mailto:CSGNET@LISTSERV.ILLINOIS.EDU] On Behalf Of Warren Mansell
Sent: Friday, March 14, 2014 1:31 PM
To: CSGNET@LISTSERV.ILLINOIS.EDU
Subject: Re: Measuring Input-Output Characteristics of Components of a Closed Loop: Redux

WM: HI Bruce, but what about when we think of those perceptual properties during development, not as they are put together in this current, unique scene, but how they were first perceived in development. The first perception of a happy face; the first perceptions of colour; perceptions of velocity - potentially the closed loop was important, maybe even essential to the formation of the perceptual functions that allows us to perceive those features now, as adults, and take it for granted, but as a child those perceptions might have been non-existent until the child started to learn how to control them, or at least influence them (e.g. to make people smile; to move an object at different speeds), etc?

BA: Perhaps.

BA: When Bill developed PCT, he was trying to develop a system that, from a very minimal starting point, could develop all the different levels of control to be found in the adult individual. The key was Ashby’s essential variables and the reorganizing system that could find solutions to the problems of control needed to keep those essential variables within survivable ranges, plus the notion that higher-level systems could emerge from the same process once there were lower-level systems whose references could be set by the higher-level systems as their means to control perceptions at their own level. My own view is that genetically/biochemically orchestrated development provides far more structure than seems to be allowed under PCT. Bill and I discussed this issue privately some time ago during one of our Skype sessions, and he was willing to agree that this may be the case, although of course he’d have to see the evidence for that. Current understanding is that basic perceptual mechanisms (such as those in vision that create perceptions of objects and their apparent properties such as color and motion) are present at birth but will deteriorate if not given adequate input during the first years – thus the importance of early restorationn of vision to those born with cataracts or “lazy eye.â€? On the other hand, having experience interacting with those products of perception must be crucially important as well. A person who has learned the shape of a ball by touch usually cannot initially relate that experience to the appearance of the ball if deprived of vision from birth and having vision subsequently made available. We learn from experience what to expect of the things we perceive and how perceptions from different senses relate, especially when attempting to control them.

Years ago when my daughter was born, the received wisdom was that newborns were unable to make any sense of the visual world around them, that it was just a blur of shapes and colors. This notion was quickly put to rest for me when I watched her move her eyes and head to track the movement of a nurse only minutes after birth. Clearly, more is available to the newborn than perception of and control over intensities.

How much is “givenâ€? and how much must be acquired is still an open question. Do we learn to judge depth or distance by interacting with objects and moving through a scene, with attendant changes in perspective and differences in apparent motion of the objects at different visual depths? Or are our visual systems already preprogrammed to render depth in the visual scene, requiring experience only for “fine tuningâ€?? I don’t think we know for sure as yet, but the answer is likely to be “it’s a bit of bothâ€? –“ nature and nurture (genetics and reorganization) interacting during development in complex ways to produce the end product.

Bruce

[From Adam Matic 2014.03.15.1100 cet]

Bruce Abbott (2014.03.14.1305)
BA: Keep in mind that most perceptions are not controlled perceptions; for example, you may see many people walking along a street. The retinas of your eyes convert the patterns of illumination produced by this scene into neural signals that are analyzed at higher levels within the brain to produce perceptions of the people, street, other objects. You are not controlling the expressions on those people’s faces, nor the style of clothing they are wearing, to mention just a couple aspects of the scene that you are not controlling. It is possible to test the perceptual system to determine what basic properties of the image go into the analysis that produces those recognizable objects, their apparent motions, colors, shading, and so on. Such tests can be done by giving participants control over those aspects, but it is not necessary to do so. Thus I disagree with your statement above that investigating perceptual functions is “like a search for the controlled variable” –unless by “like” you mean that it shares certain features of the Test. To control a perception you must be able to perceive it; investigations of perceptual functions, whether or not under control during the investigation, can help to establish exactly how perceptions are created by the relevant sensory and brain systems.

AM:
I tried starting my response from different angles, it seems best to start with basic principles. Let me know at which point I might have gotten something wrong or you disagree.
Basic hypothesis in PCT is that people are control systems. If we take it as a fact, we know that whether we apply stimuli and record responses or do tracking studies, or do any procedure, our subjects will be controlling. Any kind of research on perceptual functions with human subjects is necessarily studying someone who is doing a control task. It doesn't matter if the subject and the experimenter realize they are doing it or not.
What matters for the scientific value of an experiment is which data they choose to record, how they analyse it and how they interpret it.
If they are trying to find out what _can_ be perceived, they are doing a version of the Test. For example, subjects can't control the intensity of the Sun, but they can go into shade, wear sunglasses or close their eyes. Subjects might not be able to control directly some aspects of a stimulus researchers present them, such as it's color or shapes, but _if_ subjects can control for looking at a differently colored or shaped stimulus, we know they can perceive that aspect of the environment.
After we know subjects can perceive a variable, we can explore properties of control further. Psychophysicists certainly did that, but they didn't realize they were exploring control. They found a lot of variables that can be perceived, but not much about input functions, since they didn't even know input functions exist as part of a control loop and they didn't exclude feedback effects on the input function.

(A side note: I'm having difficulty thinking about variables that can be perceived, but not controlled. I think every variable that can be perceived can be controlled, but that might be just a semantic difference from what you are saying. I mentioned controlling the intensity of light from the Sun. Another example: if I want to see a happy face, I can go searching for a picture, I could say a joke and wait for someone to smile, or I could smile and look in the mirror. I can perceive my heart rate and while I can't control it directly, if wanted it to go up, I could start running. /end side note)

Adam

[From Adam Matic 2014.15.3.1230cet]

(Martin Taylor 2014.03.14.12.20)
MT: There is a VERY large literature on such experiments, going back over a century. The experimenter (human or machine) did something that might or might not influence some perception in the subject. Of course, the subject could not control THAT perception, since there would be no opportunity to influence the input that the experimenter had already provided. But because the subject was controlling a DIFFERENT and unrelated perception (perhaps a perception of the experimenter's perception that the subject was following instructions), the subject does tell the experimenter what he perceives. The I-O component from experimenter's input presentation to the subject's answer is a small component of the larger loop that goes through both subject and experimenter. (...)

AM:
I don't really understand what is going on in these experiments with all the smaller and larger control loops, but if you say they reveal properties of control loops, then they could also be used in making models. Is that possible and if so, how do these models perform?

AM:

That looks to me like a search for the controlled variable (which is defined in the perceptual function).

MT: What perception is being controlled here? The subject is presented with a sequence of two configurations and sees whatever that sequence produces in his perceptual system. He doesn't have to answer anything, and there's no way he can alter what was presented or what will be presented if and when there might be another trial. Who is searching for a controlled variable? The experimenter depends on the fact that the subject cannot control whether a presentation is seen as a smooth flow between two configurations or as two discrete configurations. The subject sees it the way it seems to be.

AM:
Well it's me who is searching for the controlled variable in that experiment. The subject can't at all help himself but to control his perception. That is what he is doing, because he is a control system.
More importantly, I don't know if his motion input function is a control system too. It probably is, with perception of motion being constructed from lower order visual signals. The output of this system is, I assume, going back down to lower levels. I don't think we can just ignore the feedback effects if we want to know more about this input function.
This experiment shows certain conditions in which an environmental variable can be perceived as motion. It does not show internal properties of the input function. We need models for that.

MT: I don't understand the leap you make between determining what people are able to perceive and the TCV.

AM:
The TCV is an excellent proof that a variable _can_ be perceived, I think it also works both ways, if it can be perceived, it can be controlled in some way, but I am somewhat confused about that.

MT: I'll return your "I don't see", and say "If we talk about scientific value of the TCV, I don't see the what it could possibly say about the properties of the elements of the control system, other than whether a certain variable can or can not be controlled."

AM:
I agree, that is what it is for.

MT: Understanding the properties of capacitors, resistors, diodes, and complexes such as op-amps may not tell you anything about the circuits in which they are employed, but it sure tells you about how they might be employed. The situation seems to me to be the same.

AM: Absolutely. I just think that only certain methods can really find out properties of components that are in the loop.
Adam

[From Bruce Abbott (2014.03.15.0905 EDT)]

Adam Matic 2014.03.15.1100 cet –

Bruce Abbott (2014.03.14.1305)

BA: Keep in mind that most perceptions are not controlled perceptions; for example, you may see many people walking along a street. The retinas of your eyes convert the patterns of illumination produced by this scene into neural signals that are analyzed at higher levels within the brain to produce perceptions of the people, street, other objects. You are not controlling the expressions on those people’s faces, nor the style of clothing they are wearing, to mention just a couple aspects of the scene that you are not controlling. It is possible to test the perceptual system to determine what basic properties of the image go into the analysis that produces those recognizable objects, their apparent motions, colors, shading, and so on. Such tests can be done by giving participants control over those aspects, but it is not necessary to do so. Thus I disagree with your statement above that investigating perceptual functions is “like a search for the controlled variable” –unless by “like” you mean that it shares certain features of the Test. To control a perception you must be able to perceive it; investigations of perceptual functions, whether or not under control during the investigation, can help to establish exactly how perceptions are created by the relevant sensory and brain systems.

AM:

I tried starting my response from different angles, it seems best to start with basic principles. Let me know at which point I might have gotten something wrong or you disagree.

AM: Basic hypothesis in PCT is that people are control systems. If we take it as a fact, we know that whether we apply stimuli and record responses or do tracking studies, or do any procedure, our subjects will be controlling. Any kind of research on perceptual functions with human subjects is necessarily studying someone who is doing a control task. It doesn’t matter if the subject and the experimenter realize they are doing it or not.

BA: They will be controlling, but not necessarily controlling the variable that the experimenter is investigating.

AM: What matters for the scientific value of an experiment is which data they choose to record, how they analyse it and how they interpret it.

BA: Yes, and much more.

AM: If they are trying to find out what can be perceived, they are doing a version of the Test. For example, subjects can’t control the intensity of the Sun, but they can go into shade, wear sunglasses or close their eyes. Subjects might not be able to control directly some aspects of a stimulus researchers present them, such as it’s color or shapes, but if subjects can control for looking at a differently colored or shaped stimulus, we know they can perceive that aspect of the environment.

BA: The Test determines whether a given variable is under control by the participant. To control that variable, the participant must be able to perceive it, so in that sense the Test can reveal that the participant can perceive the variable in question (if the variable is being controlled). However, when the Test is failed, this means only that the participant is not controlling that variable. The participant may perceive it quite well but not be controlling it.

AM: After we know subjects can perceive a variable, we can explore properties of control further. Psychophysicists certainly did that, but they didn’t realize they were exploring control. They found a lot of variables that can be perceived, but not much about input functions, since they didn’t even know input functions exist as part of a control loop and they didn’t exclude feedback effects on the input function.

BA: Actually, they learned quite a bit about input functions. Input functions are what psychophysics is all about – the relationship between the physical stimulus and its psychological correlate.

BA: Perhaps I can clarify the role of control in psychophysical experiments with a couple of examples. Imagine that you are getting your hearing tested. Your audiologist has you wear a set of headphones and tests you in a quiet booth. Pure tones will be presented to one ear or the other through the headphones.

BA: In the first example, the audiologist asks you to raise a finger each time you hear a tone. A series of tones is presented at different intensities and frequencies, first in your left ear and subsequently in your right. Sometimes the tone is so weak that you barely hear it, and sometimes it seems as though you should be hearing a tone (there is a silent gap) but hear nothing. At the end of the test the audiologist produces a pair of curves (one for each ear) plotting the threshold intensities at which a tone was heard as a function of tone frequency.

BA: Notice that you had no control over the presentation of the tones. You did not control their intensity, frequency, purity, and so on. What control you did exercise for the experiment involved controlling a relationship between your finger position and your perception/non-perception of a tone.

BA: Of course, to some degree you could have controlled your perception of those tones – you might have removed your headphones, for example, or pulled the headphones away from your ears a small distance to lower their perceived intensity. But that would have violated the experimental design as well as negating the validity of any data collected.

BA: The second example is like the first, except that the audiologist hands you a device with a button on top. You are instructed to press the button until you hear a tone and then immediately release it, then press and hold the button again when you no longer hear the tone. So you press the button and after a short while you begin to hear a very faint tone. You release the button and the tone fades away. After a few cycles of this the tone frequency changes, but you continue to act as before. In this manner you are exposed to a variety of tone frequencies, first in one ear, and then in the other. When the test is over, you are shown a graph indicating tone intensity as a function of time. As the graph begins, the line gradually rises from zero until it reaches a certain intensity, then begins to oscillate around a particular intensity. Then the line rises (or falls) a bit to a new level and oscillates around that. This pattern continues through the balance of the test.

BA: The audiologist tells you that each plateau represents the intensity at which a tone of a given frequency crossed the threshold for detection, oscillating slightly above and below that value. The shifts in plateau represent the changes in threshold that accompanied a change in tone frequency during the test. From the chart, the audiologist extracts two curves (one for each ear) showing the threshold intensity values as a function of tone frequency – the same curves that were produced in the first example.

BA: In this second example, you were given control over the intensity of the tones. As you held the button down, the apparatus gradually increased the physical intensity of a tone being presented to one ear via the headphones. When you began to perceive the tone, you released the button and the apparatus then reversed direction, gradually reducing the tone’s intensity until you no longer perceived it. The midpoint between the intensities at release and re-press were taken as the threshold values. The experimenter still controlled the frequency of the tones and which ear they would be directed to.

BA: The curves generated by the two psychophysical methods described here are essentially identical, and they show how your auditory system’s sensitivity to pure tones varies with their frequency. Your curves may reveal frequencies over which you have hearing loss, and can be used to tune a hearing aid to compensate (to the extent possible) for those losses by boosting the amplification at those frequencies. Yet only one method made sound intensity a controlled variable that you adjusted to a reference level of “barely audible.”

BA: If feedback somehow changes the measurements of threshold, then one would expect the two methods to produce different results. With the first method the loop is open with respect to tone intensity, whereas with the second it is closed. Yet measured thresholds are the same either way.

(A side note: I’m having difficulty thinking about variables that can be perceived, but not controlled. I think every variable that can be perceived can be controlled, but that might be just a semantic difference from what you are saying. I mentioned controlling the intensity of light from the Sun. Another example: if I want to see a happy face, I can go searching for a picture, I could say a joke and wait for someone to smile, or I could smile and look in the mirror. I can perceive my heart rate and while I can’t control it directly, if wanted it to go up, I could start running. /end side note)

BA: Given that perceptions exist in the mind/brain, it is theoretically possible to control any of them. However, we often have little or no meaningful control over the reality presumed to be reflected by those perceptions. I cannot control the sunset, but can choose to view it or not (no problem). I may want my perception of a truck hurtling toward me to go away, but if it is only the perception that goes away and not the truck, I likely will end up dead. (By the way, Douglas Adams in his Hitchhiker’s Guide to the Galaxy described an invention called “peril-sensitive glasses,” which became opaque whenever something of potential danger came into view. The glasses allowed the wearer to control the perception of danger (keeping it at zero), but of course the joke was that the danger was still there and likely to harm the wearer who goes blissfully on as if the danger no longer existed.)

Bruce

[From Adam Matic 2014.03.15.1500 cet]

Bruce Abbott (2014.03.15.0905 EDT)
BA: In the first example, the audiologist asks you to raise a finger each time you hear a tone. A series of tones is presented at different intensities and frequencies, first in your left ear and subsequently in your right. Sometimes the tone is so weak that you barely hear it, and sometimes it seems as though you should be hearing a tone (there is a silent gap) but hear nothing. At the end of the test the audiologist produces a pair of curves (one for each ear) plotting the threshold intensities at which a tone was heard as a function of tone frequency.

AM:
That looks very much like compensatory tracking. The reference level for sound intensity is zero, and raising the finger is used to reduce the intensity. Is this not the same as the experiment with the button? I don't see any difference. You move your finger in both experiments, but in one the experimenter acts as a button, and in the other one the button plays it self.
Other psychophysics experiments seem to involve a lot of explicit control tasks, such as the method of adjusting two stimuli to have the same intensity.
Adam

[From Bruce Abbott (2014.03.15.1040 EDT)]

Adam Matic 2014.03.15.1500 cet –

Bruce Abbott (2014.03.15.0905 EDT)

BA: In the first example, the audiologist asks you to raise a finger each time you hear a tone. A series of tones is presented at different intensities and frequencies, first in your left ear and subsequently in your right. Sometimes the tone is so weak that you barely hear it, and sometimes it seems as though you should be hearing a tone (there is a silent gap) but hear nothing. At the end of the test the audiologist produces a pair of curves (one for each ear) plotting the threshold intensities at which a tone was heard as a function of tone frequency.

AM:

That looks very much like compensatory tracking. The reference level for sound intensity is zero, and raising the finger is used to reduce the intensity. Is this not the same as the experiment with the button? I don’t see any difference. You move your finger in both experiments, but in one the experimenter acts as a button, and in the other one the button plays it self.

BA: No, with the first method, moving your finger has no effect on the intensity of the tone being presented. The tone is presented for a fixed period of time, then the next tone, then the next, etc. The intensity is varied between presentations according to a random or pseudo-random schedule. The only thing that raising your finger (or not) does is control the relationship between tone perception (you do or do not perceive the tone) and finger position, so that the finger is raised when you perceive the tone and not raised when you do not perceive the tone.

BA: With the second method, pressing-releasing the button allows you to vary the tone intensity so as to keep the intensity close to the intensity threshold. Thus, the second method involves a tracking task, but not the first.

AM: Other psychophysics experiments seem to involve a lot of explicit control tasks, such as the method of adjusting two stimuli to have the same intensity.

BA: Yes, they do. My point was that they do not have to provide control over the perception under investigation. Data from the first method provides valid information about the perceptual input function even though it provides no control over input tone intensity.

BA: I’ve been writing about absolute thresholds, but one can also investigate difference thresholds – how much difference there must be along some dimension between two inputs before the person can tell that they are different. In the late 19th century, Gustav Fechner used difference thresholds to construct a scale relating perceived loudness of a tone to its physical intensity. The relationship turned out to be a logarithmic one: the perceived loudness is proportional to the logarithm of the physical intensity. (This relationship was used to create the decibel scale for sound intensity.) Consequently, if you want to create an accurate PCT model of a control system for perceived sound intensity, the input function should convert physical intensity to perceptual units via a log transformation. However, that log function will give you perceived loudness from physical intensity whether or not the person is actively controlling the perceived intensity of a given source of sound.

Bruce

[From Adam Matic 2014.03.15.2120 cet]

(Bruce Abbott (2014.03.15.1040 EDT)

BA: With the second method, pressing-releasing the button allows you to vary the tone intensity so as to keep the intensity close to the intensity threshold. Thus, the second method involves a tracking task, but not the first.

My point was that they do not have to provide control over the perception under investigation. Data from the first method provides valid information about the perceptual input function even though it provides no control over input tone intensity.

AM:

I remember having my hearing checked once using the following method: the technician would play a tone from a randomized list of frequencies, starting with inaudible intensity and increasing. I was told to say “Yes” when I hear a tone, and the tone would stop. I think I really was controlling sound intensity and keeping it at zero.

If we are trying to find the absolute threshold for each frequency, it makes sense to either start from low intensity and go up until we cross the threshold, or start from audible intensity and go down until there is no sound.

I see tracking in both cases. But even if intensity was completely random, if we get the same measurements for thresholds in the tracking task and the supposedly non-tracking task, we’d have to conclude that there is intensity control in both cases.

Similarly, perhaps the apparent motion experiments Martin mentioned could be viewed as compensatory tracking and threshold measurement for motion detection.

BA: I’ve been writing about absolute thresholds, but one can also investigate difference thresholds – how much difference there must be along some dimension between two inputs before the person can tell that they are different. In the late 19th century, Gustav Fechner used difference thresholds to construct a scale relating perceived loudness of a tone to its physical intensity. The relationship turned out to be a logarithmic one: the perceived loudness is proportional to the logarithm of the physical intensity. (This relationship was used to create the decibel scale for sound intensity.) Consequently, if you want to create an accurate PCT model of a control system for perceived sound intensity, the input function should convert physical intensity to perceptual units via a log transformation. However, that log function will give you perceived loudness from physical intensity whether or not the person is actively controlling the perceived intensity of a given source of sound.

AM:

That also sounds like a control task. It is interesting how they found ways to examine some properties of control processes more than 100 years ago, and without understanding control systems. I remember reading that psychophsyics was criticised as not scientific because it was “subjective”.

I’m still not clear about this concept of “uncontrolled perceptions” and its role in research. I might be wrong, but I just don’t see how that would work.

Adam

[From Bruce Abbott (2014.03.17.1020 EDT)]

Adam Matic 2014.03.15.2120 cet –

(Bruce Abbott (2014.03.15.1040 EDT)

BA: With the second method, pressing-releasing the button allows you to vary the tone intensity so as to keep the intensity close to the intensity threshold. Thus, the second method involves a tracking task, but not the first.

My point was that they do not have to provide control over the perception under investigation. Data from the first method provides valid information about the perceptual input function even though it provides no control over input tone intensity.

AM:

I remember having my hearing checked once using the following method: the technician would play a tone from a randomized list of frequencies, starting with inaudible intensity and increasing. I was told to say “Yes” when I hear a tone, and the tone would stop. I think I really was controlling sound intensity and keeping it at zero.

BA: O.K., if that’s what you were doing, then you were using your behavior (saying “yes”) to bring the perceived tone intensity back to zero, once you perceived the tone, and you were therefore controlling tone intensity.

AM: If we are trying to find the absolute threshold for each frequency, it makes sense to either start from low intensity and go up until we cross the threshold, or start from audible intensity and go down until there is no sound.

BA: Yes, and that is what is done using the Békésy method, a version of which I labeled the second of the two methods I described earlier.

AM: I see tracking in both cases.

BA: Yes, as you interpret what you were doing when saying “yes,” both methods are examples of tracking.

AM: But even if intensity was completely random, if we get the same measurements for thresholds in the tracking task and the supposedly non-tracking task, we’d have to conclude that there is intensity control in both cases.

BA: That’s a non-sequitur. The test of whether a loop is open or closed is not whether the two procedures generate the same input function, but whether the participant’s behavior feeds back to affect the variable putatively under control. In the first method I described, the participant’s raising or lowering of a finger has no effect on the presentation of any aspect of the tones. Whether the participant raises a finger or not, the tones get presented for the same duration and at the frequency and intensity specified by the audiologist. It’s a very clear case.

BA: There is of course control going on in that procedure, however. As I described previously, the finger is being used to control a relationship between finger position and perception of the tone, such that the finger is raised when the tone is perceived and lowered when the tone is not perceived.

Similarly, perhaps the apparent motion experiments Martin mentioned could be viewed as compensatory tracking and threshold measurement for motion detection.

BA: Not if “similarly” follows from your incorrect assertion that the open-loop threshold test is really a closed loop test.

BA: I’ve been writing about absolute thresholds, but one can also investigate difference thresholds – how much difference there must be along some dimension between two inputs before the person can tell that they are different. In the late 19th century, Gustav Fechner used difference thresholds to construct a scale relating perceived loudness of a tone to its physical intensity. The relationship turned out to be a logarithmic one: the perceived loudness is proportional to the logarithm of the physical intensity. (This relationship was used to create the decibel scale for sound intensity.) Consequently, if you want to create an accurate PCT model of a control system for perceived sound intensity, the input function should convert physical intensity to perceptual units via a log transformation. However, that log function will give you perceived loudness from physical intensity whether or not the person is actively controlling the perceived intensity of a given source of sound.

AM:

That also sounds like a control task. It is interesting how they found ways to examine some properties of control processes more than 100 years ago, and without understanding control systems. I remember reading that psychophsyics was criticised as not scientific because it was “subjective”.

BA: What sounds like a control task? Fechner’s derivation of the logarithmic relation between physical stimulus intensity and perceived intensity? A PCT model of a control system for perceived sound intensity that uses a logarithmic input function? (That’s a control system, of course.) I’m afraid I don’t understand your referent here.

I’m still not clear about this concept of “uncontrolled perceptions” and its role in research. I might be wrong, but I just don’t see how that would work.

BA: I must admit to being baffled by your difficulty in understanding the concept of an uncontrolled perception. I’ve tried to explain it as clearly as I know how; consequently I don’t know how to proceed from here. Do you believe that all aspects of all the variables you perceive are under your personal control, all of the time? Or do you attempt to control only some aspects of some perceptions? In my view, the universe of variables I can perceive but either cannot or do not control is huge relative to the universe of variables I do control.

Bruce

[From Bruce Abbott (2014.03.17.1050 EDT)]

Rick Marken (2014.03.14.1220)

Warren Mansell writes:

WM: But I also feel that Rick’s purist stance, despite his stubborn refusal to acknowledge the worth of S-R research, brings the clarity of purpose that is needed to head the direction of science clearly towards what we learn through PCT.

RM: I’m glad that you appreciate my point of view but I’ve got to tell you that referring to it as “purist” makes me very uncomfortable. I think of purist stances as those taken by ideologues (or racists) and such stances encourage the purging (or worse) of the “impure”. I think of myself as taking a scientific rather than an ideological stance – the same scientific stance taken by Powers in the 1978 Psych Review article where he showed that the S-R approach to studying living control systems tells you very little about what is important about the behavior of these systems: the perceptual variables that are being controlled when we observe various behaviors. And I have no interest in purging (or worse) people who don’t agree with the “stance” Powers took in that brilliant paper.

RM: I don’t think Bruce and Martin, the main defenders of the S-R approach to research, are “impure”. I think they are simply wrong. I can understand why they are defending the S-R approach but I think their stance is impeding (or, at least, not helping with) the development of a PCT-based science of life. So I will continue to try to convince them that they should drop the S-R stuff , not because the S-R stuff is impure but because it’s misguided (as explained by Bill in the 1978 Psych Review paper). And I will continue to encourage them (and other researchers) to start developing ideas for research based on PCT so that we can start implementing Bill’s vision of a science of living control systems, as described in the “Cybernetic Model for Research” paper in LCS I.

BA: When you describe Martin and I as “defenders of the S-R approach to research” the reader might get the impression that we are promoting “S-R research” in opposition to PCT. Of course we are doing nothing of the kind. Interesting that you think that what we have been doing “is impeding . . . the development of a PCT-based science of life.” I can’t speak for Martin, but for my part, I see some of your efforts as serving to impede the development of PCT, even though I know that this is exactly the opposite of your intention. When you present arguments or assertions that are demonstrably untrue, you damage the credibility of PCT in the eyes of those who know better. I know that you have only the best intensions, Rick, but raising objections and criticisms that are based on a faulty understanding of certain principles does nothing to help the PCT cause, and may hurt it. We’re working toward the same objective, but unfortunately we seem to have very different views as to whether discussing such things whether one can get valid data about input functions from “S-R” experiments is helping or hindering the future of PCT.

Bruce

[Martin Taylor 2014.03.15.11.14]

You may well be right, and J.G.Taylor's work, as well as the work of

such others as Hein and Held in the 1960s, suggests you are. You can
change the sun angle above the horizon level to whatever you want if
you can run/fly fast enough. But usually you don’t do that. You let
the sun be wherever it is, and the resulting shadow configurations
as whatever results from its current position.
The point of the TCV isn’t what might be controlled, but what Is
being controlled out of the multi-millions of perceptions that you
have at any one moment (using “perceptions” in the PCT sense of a
sensory signal dependent on past or present sensory information).
Just look around you for just those few perceptions of which you are
consciously aware. Is there a bookcase in your field of view? Do you
see wide lighter vertical stripes separated by dark thin stripes
(books and the strip between them). On the lighter stripes do you
see patterns of different colour? Do some of the smaller of those
patterns form characteristic shapes (the letters of words on the
spine). How many of these conscious perceptions from one bookcase
and one book are you at that moment actively and individually
controlling? Or look at a tree in the wind, in which you see
thousands of leaves fluttering in their individual rhythms, showing
their vein patterns at different sun angles and in varying shade.
How many of those fluttering leaf positions and vein patterns are
you actively controlling at this moment? How many trees would you
see if you were in a meadow looking at a woodlot nearby?
Let’s consider some numbers. We have at most a few hundred
individually controllable muscles. All any one of those muscles can
do is get shorter or longer. We do emit chemicals, but not more than
a few tens of truly distinctive ones. Suppose that someone highly
trained is able to command all of these outputs individually and
independently, and could do so with a bandwidth of, say, 10 Hz. That
is to say that the person is able to produce 20 different and
unrelated lengths for each of, say, 250 muscles every second
continuously. That is a control rate of 500 degrees of freedom per
second. That vast overestimate (the true number is more likely to be
nearer 10 or 20 df/sec) is what we have available for control. Any
attempt to control more than that through the environment (as
opposed to “in imagination”) will inevitably result in conflict
inside the control hierarchy.
Now consider the possible perceptions that might be controlled. One
approach is to look at the input sensory system, considering just
orders of magnitude: visual – never mind the hundred million or so
receptor cells – the optic nerve has around a million independent
fibres with bandwidths in the 10Hz plus range; auditory, about
30,000 fibres; tactile, i’ve no idea how many sensory fibres, but
there must be a lot. You get the idea. The input sensory bandwidth
is in the tens of millions of degrees of freedom per second. It is obvious that the true perceptual degrees of freedom is not
given by the number of fibres, since their firings are coordinated
by the coherence of the scenes, soundscapes, and other sensed
aspects of the environment. Optic input is coordinated into gross
features such as moving spots, edges, lines and the like. Directed
motion shape detectors such as these are probably the lowest level
of the perceptual hierarchy, but if the lowest level is, as Powers
would have it, “intensity”, that only makes the problem worse,
because each input fibre conveys an intensity signal (really a
time-differential intensity signal in most cases) in its individual
firing rate.
So, we have at least millions of perceptions available for control
at the lowest level, all possibly changing at a rate above 1 Hz. If
we tried to control them all at the same time, our control structure
would get into the mother of all conflicts, and would probably be
able to control nothing at all. We do have to control only some of
them, leaving most uncontrolled at any one moment – though we could
shift which ones we control to any small subset of the myriad
possibilities. Shifting what we control is a very important part of PCT. It’s in
Chapter 2 of LCSIII, albeit at a very much higher level, where the
degrees of freedom limit is imposed by the environment, not the
organism.

···

[From Adam Matic 2014.03.15.1100 cet]

        (A side note: I'm having difficulty

thinking about variables that can be perceived, but not
controlled. I think every variable that can be perceived can
be controlled,

AM:

  I don't really understand what is going on

in these experiments with all the smaller and larger control
loops, but if you say they reveal properties of control loops,
then they could also be used in making models. Is that possible
and if so, how do these models perform?

  Bruce and I both answered the direct question of how the models

perform, so I’ll try to help with “smaller and larger control
loops”.

  We don't need to enquire what the experimenter is controlling for

which the action output is running the experiment. For some reason
the experimenter wants to know something, and to investigate
“wanting to know” opens a whole can of worms. Trying to not open
this can, consider simply asking a question:

  Q (Questioner): "Is it raining?"

  R (Responder): (1) "I don't want to tell you" or (2) "I can't see"

or (3) “Yes” or “No”

  I think you must agree that all these QA pairs are possible, and

that because asking the question is an action, Q must be
controlling some perception for which Q imagines R’s answer will
reduce the error. I’m not going to enquire into that control loop
here, because it brings up some issues relating to B:CP Chapter 4,
and that’s an entirely different thread if and when those issues
might be raised.

  Whatever the perception Q is controlling, R's answers may affect

different perceptions Q has about R. These affected perceptions
may or may not be controlled by Q, but that’s irrelevant at this
point. It would be relevant to the continuation of the dialogue,
but we aren’t analyzing that.

  Answer 1: Q can perceive that R is not controlling for perceiving

R-self as being cooperative. Q’s perception of raininess is not
affected.

  Answer 2: If Q currently perceives R to be controlling for being

cooperative, Q can perceive that R is unable to see whether it is
raining. Q’s perception of raininess is unaffected. Q must
perceive R to be controlling for being cooperative, becasuse if Q
does not perceive this, R might say “I can’t see” because he is
controlling for seeing himself as not helping Q.

  Answer 3: If Q currently perceives R to be controlling for being

cooperative, Q can perceive that R is able to see whether it is
raining. If Q perceives R to be good at distinguishing “raining”
from “not raining” states, Q’s perception of raininess is closely
determined by whether the answer is “Yes” or "No’ (or “lightly” or
“pouring” or other modifiers).

  Only if Q perceives R to be controlling for perceiving R-self to

be cooperative will Answers 2 or 3 affect Q’s perception of
whether R can see if it raining or Q’s perception of raininess. So
if Q wants to know whether R can see, Q has to at least test
whether R is controlling for being cooperative by asking some
other questions (changing disturbances in the TCV). Q may have to
act if Q’s perception of R’s cooperativeness differs from Q’s
reference value for that perception.

  On the other hand, if Q is interested in whether it is in fact

raining, R’s cooperativeness doesn’t matter unless Q perceives R
to be actively deceptive (a short form for perceiving R to be
controlling a perception of Q as perceiving to be true something R
perceives to be untrue – itself a short form for a long
rigmarole).

  At the end of all this, assuming Q perceives R to be cooperative

and physically and mentally able to distinguish “raining” from
“not raining”, Q has a current perception of whether it is
raining. Is Q controlling that perception? Not if Q is an ordinary
human, but Q probably IS controlling a perception created by a
perceptual function into which the perception of raininess feeds.
R has served the function of a tool, such as a telescope or a
mirror, which would allow Q to perceive something too distant or
obscured.

  So far so good?

  Now suppose that before asking the questions, Q knows whether it

is raining, and has done the tests that allow R to be perceived as
cooperative. I repeat the Q-A possibilities from above:

  Q (Questioner): "Is it raining?"

  R (Responder): (1) "I don't want to tell you" or (2) "I can't see"

or (3) “Yes” or “No”

  Answer (1) is very unlikely, so we consider Answers (2) and (3).

In both cases, the answer tells Q only something about R, not
about raininess. If R gives answer 2, or if R says “Yes” when Q
can see that the correct answer is “No” (or vice-versa), Q may
perceive that R is not able to see whether it is raining. If the
Answer is (2), Q may also perceive that R perceives that he cannot
see, whereas if it is (3), Q can perceive that R perceives that he
can see, but that R’s self-perception is misguided.

  On the other hand, if R's answer "Yes" or "No" agrees with Q's

direct knowledge of the correct answer, there’s only a 50-50
chance that this occurred because R is actually able to see
whether it is raining. If Q wants to find out whether R is able to
tell the difference between raining and not raining, Q has to try
the same question on different occasions, sometimes when it is
raining, sometimes when it isn’t. Each time R’s answer agrees with
Q’s perception reduces by 50% that chance that R doesn’t see
“raining” differently from the way Q sees it.

  It might turn out that when the rain is spotty or a light drizzle,

R’s answers agree with Q’s perception of raininess 75% of the
time, but when the rain is heavier or under a clear blue sky the
agreement is 100%. Q may then perceive that for R to say it is
raining, the rain must be, say, heavier than is required for Q to
perceive it is raining. Q has learned something about how R
perceives raininess, or rather about how R labels different
degrees of rain.

  Translate this into the context of an experiment. Q is now the

experimenter, and controlling a perception of R’s cooperativity
and a perception of R’s understanding of the task, Q presents two
noise bursts in quick succession, with a 500 Hz tone embedded in
one of them. R has been instructed to say “Yes” if the tone is in
the first noise burst, “No” if it is in the second, and never to
say “I can’t hear it”.

  Q: "Is the tone in the first noise burst"

  R: (1) N/A or (2) N/A or (3) "Yes" or "No"   (using the numbering

from above, answers (1) and (2) should not happen.

  If Q has placed the tone in the first noise burst, but R says

“No”, Q perceives that R did not hear the tone. But if R says
“Yes” that could happen as much as 50% of the time if R did not
hear it, but would happen 100% of the time (assuming R control
perfectly for being cooperative) if R did hear it.

  Q asks the question multiple times using the same intensities of

noise burst and tone. Sometimes R’s answers correspond with Q’s
insertion of the tone into the first or second noise burst
(correct answers), sometimes they don’t (wrong answers). For each
wrong answer, Q perceives that R did not hear the tone, but for
each correct answer Q perceives only that R might have heard the
tone. After a lot of questions, Q has a “percentage correct” score
for that particular pairing of noise level and tone intensity. If
the percent correct score is 50% Q can be pretty sure R cannot
hear the tone under those conditions, and if it is 100%, Q can be
pretty sure R can hear it.

  But what if the percent correct is intermediate? For a given noise

level and tone intensity, one might naively think that either R
will hear the tone or will not hear it. But the nature of noise
ensures that sometimes the random nature of the noise will make it
seem as though a tone was in the burst and sometimes the phasing
of that frequency band of the noise will cancel a tone that is
actually inserted. The louder the tone, the less likely it is that
this randomness will affect which noise burst is heard as having
the tone. There’s a whole mathematical literature on this from the
1950s and 1960s (to which I contributed), and a mathematically
ideal listener can be defined. The percent correct that would be
achieved by the ideal observer, plotted as a function of the
relative intensities of the tone and noise, defines the ideal
“psychophysical function”. No real observer can get a better score
than that. The point of mentioning it here is to show that there’s
a problem in interpreting percent correct literally as a measure
of R’s ability to hear a tone in a noise burst.

  The statistical problem is actually quite easily handled, and

there’s a big literature about it. The only point in mentioning it
is to illustrate that even if there are statistical issues of
interpretation, Q can learn something about R’s ability to hear by
doing something that is directly equivalent to asking a simple
question to determine whether R knows something or is able to do
something. The “larger control loop” is the one in which Q
controls for R to understand the question and to be cooperative in
answering it.

  Here I'm going to quote from an old message of mine [Martin Taylor

2012.12.08.11.32] about measurement. It deals with measuring an
inanimate property, in this case the weight of a stone.

  -----------start quote--------
    To see why control can be considered to be

measurement, think of this example. Alice wants to know how
heavy is a stone she has picked up. She has a balance scale and
a set of weights weighing 2, 1, 1/2, 1/4 … kilos. She puts the
stone on one pan, and the scale tilts down to the side on which
she put the stone, so she puts a weight on the other pan. The
tilt stays the same, so she adds another weight and the scale
tilts the other way. Alice removes the last weight she added and
adds the next lighter one. She keeps adding and removing weights
until the scale stays level or she runs out of ever smaller
weights.

    What is Alice doing? Alice is performing the actions of the

output function of a control loop, looking at the error that is
shown by the tilt of the scale, and altering her output (the
weights on the other pan) until the error is zero. The output,
which is the sum of the weights in the other pan, now is a
measure of the weight of Alice’s stone in exactly the same way
that the output of any control system measures the disturbance
to its controlled environmental variable.

    Of course, there need be no human Alice in this story. The

perceptual function signals only the direction in which the
scales tilt, so the error is only a binary value, which could be
called “1” or “0”, “left” or “right”, “too heavy” or “too
light”, or any other contrasting labels. I will call the values
“left” and “right” according to which side of the scale is
heavier. Likewise, there is no need for Alice to provide the
output function. It could be a mechanical device that is
provided with the weights that have values in powers of two
times 1 kilo, with 2 kilos the heaviest. We can assume that the
scale would break if the stone was over 4 kilos!

    The output device would load and unload these weights onto and

off the scale pan according to the following algorithm. The
stone is on the left pan.

    1. Add to the  right-hand pan the heaviest weight not yet tried

(initially, since none have been tried, that means the 2 kilo
weight).

    2. If all the available weights have been tried, stop. Else...

    3a. If the error is "left" go to step 1 (there is not enough

weight in the right hand pan)

    3b, if the error is "right", remove the lightest weight in the

pan and add the heaviest weight not yet tried.

    At the end of this process, the balance is as close as the

machine (or Alice) can make it using the available weights.
Anyone who wanted to know the weight of the stone could simply
read out the weights in the pan as a binary number of kilos,
with the units starting at the 2 kilo weight. Those weights are
the current output value of the control system., which, without
Alice, is a perfectly standard control loop.
---------------end quote--------

  This "weighing a stone" procedure describes in principle any

measurement, whether done by a human or a machine. In particular,
the entity measured might be some property of an organism. The
“stone on the left pan” might be the ability of a subject to
discriminate
between the brightnesses of two patches. The balance “Left” or
“Right” could be whether the subject’s response is right or wrong.
If the subject was correct, reduce the brightness difference
(remove a weight from the pan), else increase the brightness
difference (add a weight to the pan).

  There are two problems with this when the measurement is of a

property of an animate entity. One is that the result is
inherently noisy for a variety of reasons. That’s not interesting
here because there are statistical techniques for reducing the
effect of the noise by altering the algorithm. The other is that
the subject has to be controlling a perception for which the error
is reduced by reporting accurately to the best of her ability –
colloquially, the subject must try to get it right, which we
covered above.

  I hope this long-winded explanation at least may guide you to

answering your on question, if it doesn’t do so directly.

  Martin

[From Adam Matic 2014.03.17]

BA: The test of whether a loop is open or closed is not whether the two procedures generate the same input function, but whether the participant’s behavior feeds back to affect the variable putatively under control. In the first method I described, the participant’s raising or lowering of a finger has no effect on the presentation of any aspect of the tones. Whether the participant raises a finger or not, the tones get presented for the same duration and at the frequency and intensity specified by the audiologist. It’s a very clear case.

BA: There is of course control going on in that procedure, however. As I described previously, the finger is being used to control a relationship between finger position and perception of the tone, such that the finger is raised when the tone is perceived and lowered when the tone is not perceived.

AM:
I’ll try to keep it short. I have difficulty trying to imagine what is going on in these multi-level loops. I don’t trust I’ve made a correct analysis of what is going, but I also don’t trust that you’ve done that. It might be, but we need multi-level models and comparisons with real people’s behavior to determine that.

The main problem I see is that there is always feedback on lower levels of perception. There are muscles in the inner ear, there are iris muscles in the eye, there are a lot of these small loops connected trough the environment affecting inputs. Those loops are not broken when there is no effect of saying yes or raising a finger and they do affect perception of stimuli.

The other problem is with how the higher levels of perception are constructed from signals from lower levels. The perception of “relationship between finger and sound” is constructed from perceptions of finger position and intensity of tone, so intensity of tone can’t be an uncontrolled perception - perhaps its reference is changed after rising the finger. Or gain?

BA: I must admit to being baffled by your difficulty in understanding the concept of an uncontrolled perception. I’ve tried to explain it as clearly as I know how; consequently I don’t know how to proceed from here. Do you believe that all aspects of all the variables you perceive are under your personal control, all of the time? Or do you attempt to control only some aspects of some perceptions? In my view, the universe of variables I can perceive but either cannot or do not control is huge relative to the universe of variables I do control.

AM:
I am a bit baffled myself, but I’ll stick to it for now.
No, I don’t think all aspects of environment can be controlled, but I do think I set my own reference values for those aspects of the environment. If something is perceived, and there is no ‘behavior’ then with taking gain into account - it is close to its reference. Is gain somehow changed in these uncontrolled perceptions? Are there models of this?

Adam

[Martin Taylor 2014.03.17.13.09]

[From Rick Marken (2014.03.14.1220)]

...
I don't think Bruce and Martin, the main defenders of the S-R approach to research, are "impure". I think they are simply wrong.

Let's just see when "defending" S-R research would be "wrong". There are lots of such conditions, but there are also conditions in which it is not wrong.

It would be wrong to defend S-R research when the conditions are not S-R, meaning that the "response" could influence the "stimulus".

It would be wrong to defend S-R research if the behaviour that constituted the measured "response" was the output of a control system with a varying reference value -- for example "stimulus" = food dish, "response" = quantity eaten, when the reference value for amount eaten can change dramatically.

It would be wrong to defend S-R research when the same "stimulus" is applied to subjects under conditions different from the conditions in which the results are later used (often in extrapolating lab results to the everyday world).

It would not be wrong to defend S-R research in which the "response" cannot influence the "stimulus", when the experimenter has properly determined that the subject is controlling for following instructions and is able to do so, and when the data are coordinated only over conditions in which the experimenter can be assured (by using the TCV) that the subject is actually controlling the same perception at the same reference value (e.g. to say "Yes" when a flash of light is detected.

I can understand why they are defending the S-R approach

The nature of your understanding might be interesting to analyse. You have apparently executed the TCV on us to discover the controlled variable above the one we control when we do defend some kinds of S-R research (the "why" of it), but I haven't been aware of any variation of disturbances other than trying out different kinds of mathematical inexactitudes and off-target simulations. Those don't seem addressed to finding the higher-level controlled variable in question. Anyway, Bruce and I have controlled whatever it might be by rather different actions, which might or might not suggest our two "why"s could be different.

but I think their stance is impeding (or, at least, not helping with) the development of a PCT-based science of life.

Actually, I think your refusal to accept normal maths, or normal (non-magical) physics, or normal engineering approaches to circuit analysis leads potentially effective scientists to avoid PCT, which they might well see as the domain of flakes and faith-healers. These potentially useful developers of PCT are quite apart from the number of people who have been subjected to your furious manner of informing them of the error of their ways when they have ventured to suggest something beyond what Bill Powers had suggested. A lot of such people have left CSGnet entirely, but I know some still lurk but don't post because they can imagine that their contribution would be summarily dismissed.

Saint Patrick didn't rid Ireland of snakes, because there were never any there. Saint Richard can't rid CSGnet of S-R theorists, because there aren't any there.

So I will continue to try to convince them that they should drop the S-R stuff , not because the S-R stuff is impure but because it's misguided (as explained by Bill in the 1978 Psych Review paper). And I will continue to encourage them (and other researchers) to start developing ideas for research based on PCT

Well, I was aware that you rarely read my messages, despite commenting on them very critically, but I was not aware that your failure to read extended quite so far as to recommend that we "start developing ideas for research based on PCT". That's quite remarkable.

so that we can start implementing Bill's vision of a science of living control systems, as described in the "Cybernetic Model for Research" paper in LCS I.

That is an objective on which we can agree. I just happen to think that it can be done within the framework of normal science, and not only within a bubble separated from the rules that apply elsewhere.

It is a great detriment to the advancement of a science of living organisms if it can be done only by rewording a small part of what has already been written by Bill. I don't think he would ever have wanted that, however much he liked being known as the initiator of a legitimate new branch of the life sciences. To require any researcher who is allowed to advance PCT to live only in this bubble is to ensure that Bill's vision does not come to pass.

Martin

[From Adam Matic 2014.03.17]

Martin, the length of your response is quite overwhelming. I've come to appreciate simulations for they can convey a lot more in a lot less time and lot more clarity. If a picture is worth a thousand words, a model is book-worth. Thank you for your effort, though. I'll try to communicate my response as a model, since I disagree with some things you say. Also, I am not sure that I am right and I need to check that by simulation.

Adam

[Martin Taylor 2014.03.17.16.32]

[From Adam Matic 2014.03.17]

> BA: The test of whether a loop is open or closed is not whether the two procedures generate the same input function, but whether the participant�s behavior feeds back to affect the variable putatively under control. ...
> BA: There is of course control going on in that procedure, however. As I described previously, the finger is being used to control a relationship between finger position and perception of the tone, such that the finger is raised when the tone is perceived and lowered when the tone is not perceived.

AM:

The main problem I see is that there is always feedback on lower levels of perception. There are muscles in the inner ear, there are iris muscles in the eye, there are a lot of these small loops connected trough the environment affecting inputs. Those loops are not broken when there is no effect of saying yes or raising a finger and they do affect perception of stimuli.

Sure, but these are all part of the environment of the control unit that controls for equality between teh tested perception and the intended output answer. If they are good controllers, they are irrelevant to the quesiton at issue. All they do is ensure that the answer output is the one for which the relationship perceiver's output created the reference value. If they affect the perception of following stimuli, that's irrelevant to the one that just happened.

The other problem is with how the higher levels of perception are constructed from signals from lower levels. The perception of "relationship between finger and sound" is constructed from perceptions of finger position and intensity of tone, so intensity of tone can't be an uncontrolled perception - perhaps its reference is changed after rising the finger. Or gain?

Why can't it be an uncontrolled perception? Lots of the inputs to any higher-level perception are unconrtrolled. Why do you have a problems with that?

Martin

Hi Adam,

Your critical notes about not trusting “anybody” even
yourself, “stimulated my respons” J.

AM:

I’ll try to keep it short. I have difficulty trying to imagine what is going on
in these multi-level loops. I don’t trust I’ve made a correct analysis of what
is going, but I also don’t trust that you’ve done that. It might be, but we
need multi-level models and comparisons with real people’s behavior to
determine that.

HB:

I think you are on a good way. Multilevels seemed to be analyzed good
in PCT, but also my oppinion is that they need improvement in accordance not
only to “real people’s behavior”, but also in accordance to researches
that show how internal structures of organisms are formed and how they
function. There are many theories, but few “match” the logic of nature.

AM:

I am a bit baffled myself, but I’ll stick to it for now.

HB:

Well, I would say wise decission J. I hope I’ll participate in
encouraging you to go on…

Best, (pozdrav u sunčani Split)

Boris

···

From: Control Systems Group
Network (CSGnet) [mailto:CSGNET@LISTSERV.ILLINOIS.EDU] On Behalf Of Adam Matic
Sent: Monday, March 17, 2014 6:34
PM
To: CSGNET@LISTSERV.ILLINOIS.EDU
Subject: Re: Measuring
Input-Output Characteristics of Components of a Closed Loop: Redux

[From Adam Matic 2014.03.17]

BA: The test of whether a loop is open or closed is not whether the two
procedures generate the same input function, but whether the
participant’s behavior feeds back to affect the variable putatively under
control. In the first method I described, the participant’s raising
or lowering of a finger has no effect on the presentation of any aspect of the
tones. Whether the participant raises a finger or not, the tones get
presented for the same duration and at the frequency and intensity specified by
the audiologist. It’s a very clear case.

BA: There is of course control going on in that procedure, however.
As I described previously, the finger is being used to control a relationship
between finger position and perception of the tone, such that the finger is
raised when the tone is perceived and lowered when the tone is not perceived.

AM:

I’ll try to keep it short. I have difficulty trying to imagine what is going on
in these multi-level loops. I don’t trust I’ve made a correct analysis of what
is going, but I also don’t trust that you’ve done that. It might be, but we
need multi-level models and comparisons with real people’s behavior to
determine that.

The main problem I see is that there is always feedback on lower levels of
perception. There are muscles in the inner ear, there are iris muscles in the
eye, there are a lot of these small loops connected trough the environment
affecting inputs. Those loops are not broken when there is no effect of saying
yes or raising a finger and they do affect perception of stimuli.

The other problem is with how the higher levels of perception are constructed
from signals from lower levels. The perception of “relationship between
finger and sound” is constructed from perceptions of finger position and
intensity of tone, so intensity of tone can’t be an uncontrolled perception -
perhaps its reference is changed after rising the finger. Or gain?

BA: I must admit to being baffled by your difficulty in understanding the
concept of an uncontrolled perception. I’ve tried to explain it as
clearly as I know how; consequently I don’t know how to proceed from
here. Do you believe that all aspects of all the variables you perceive
are under your personal control, all of the time? Or do you attempt to
control only some aspects of some perceptions? In my view, the universe
of variables I can perceive but either cannot or do not control is huge
relative to the universe of variables I do control.

AM:

I am a bit baffled myself, but I’ll stick to it for now.

No, I don’t think all aspects of environment can be controlled, but I do
think I set my own reference values for those aspects of the environment. If
something is perceived, and there is no ‘behavior’ then with taking gain into
account - it is close to its reference. Is gain somehow changed in these
uncontrolled perceptions? Are there models of this?

Adam

No virus found in this message.

Checked by AVG - www.avg.com

Version: 2014.0.4336 / Virus Database: 3722/7206 - Release Date: 03/17/14

From Adam Matic 2014.03.17]

MT: Sure, but these are all part of the environment of the control unit that controls for equality between the tested perception and the intended output answer. If they are good controllers, they are irrelevant to the quesiton at issue. All they do is ensure that the answer output is the one for which the relationship perceiver's output created the reference value. If they affect the perception of following stimuli, that's irrelevant to the one that just happened.

AM:
Let me backtrack a second.
The issue is whether we've learned something about input functions from the experiment with sound frequency thresholds.
What we get, following either of mentioned procedures of measuring absolute thresholds, is a curve, a list of limits for respective frequencies. That is it. That is not an input function. It can be viewed as useful information about control, since we found what is the possible controlled variable - i.e. for each frequency it is any sound above the threshold intensity. That is why I think this experiment is no more than the TCV. The experiment is not useless or invaluable, but it does not speak about _input function_. Well, perhaps we could say it tells us what the lower limit of the input function is, if that makes sense.
Bruce, you mentioned difference thresholds. They are a different beast. They might give more information about control of difference between two intensities. I won't rush with conclusions. What properties of the control loop, on what levels, would you say are related to the difference limen?

MT:
The other problem is with how the higher levels of perception are constructed from signals from lower levels. The perception of "relationship between finger and sound" is constructed from perceptions of finger position and intensity of tone, so intensity of tone can't be an uncontrolled perception - perhaps its reference is changed after rising the finger. Or gain?

Why can't it be an uncontrolled perception? Lots of the inputs to any higher-level perception are unconrtrolled. Why do you have a problems with that?

AM:
I have problems with this because I don't know how to make a model that would pick and choose different perceptions to control or not control, so I don't know how that would work, and I'm confused what even means "an uncontrolled perception".
In a standard tracking task like the TrackAnalyse, one of the sticks is moving as the reference, one of them is moving as the cursor. The reference stick is not 'under control'. It is not even perceived on this level. The cursor stick is also not 'under control' on this level. We have found out that what is under control can can be approximated by a function: difference = cursorPosition - referencePosition. That is an approximation of what is under control, and a very good one, since we get good RMS and correlation measures.
Is there really a perception of cursor position as a neural magnitude and another perception of 'reference stick position', and then a neuron that takes a difference between those two? There could be, and that would mean the retina has some sort of coordinate system and tracks positions of objects relative to something else.
There could also be a function that directly perceives this difference as the length of an invisible stick that comes between the cursor and the reference. Perhaps this perception of difference is related to time that it takes eyes to focus from one stick to another. Perhaps it is related to eye muscle effort in moving from one position to another. Or both of those things. I don't know, the visual system is very complex, as is the auditory system. I don't think we can just say, 'this is clearly an uncontrolled perception'.
Adam

[From Adam Matic 2014.03.17 1130 cet]

···

On Tue, Mar 18, 2014 at 9:37 AM, Boris Hartman boris.hartman@masicom.net wrote:

HB:

I think you are on a good way. Multilevels seemed to be analyzed good
in PCT, but also my oppinion is that they need improvement in accordance not
only to “real people’s behavior”, but also in accordance to researches
that show how internal structures of organisms are formed and how they
function. There are many theories, but few “match” the logic of nature.

Hi Boris.

My not trusting myself with prediction of behavior of multilevel loops comes from many months of failing to tune multilevel loops, with just simple two or three levels of control. I find them very confusing and fascinating at the same time, and just verbally explaining what is happening does not cut it. I think we need more models that do stuff so we can try to understand them better.

HB:

Well, I would say wise decission J. I hope I’ll participate in
encouraging you to go on…

Best, (pozdrav u sunèani Split)

Thanks, lijepi pozdrav!

Adam

[From Bruce Abbott (2014.03.18.0945 EDT)]

Adam Matic 2014.03.17 –

MT: Sure, but these are all part of the environment of the control unit that controls for equality between the tested perception and the intended output answer. If they are good controllers, they are irrelevant to the quesiton at issue. All they do is ensure that the answer output is the one for which the relationship perceiver’s output created the reference value. If they affect the perception of following stimuli, that’s irrelevant to the one that just happened.

AM:

Let me backtrack a second.

AM: The issue is whether we’ve learned something about input functions from the experiment with sound frequency thresholds.

AM: What we get, following either of mentioned procedures of measuring absolute thresholds, is a curve, a list of limits for respective frequencies. That is it. That is not an input function. It can be viewed as useful information about control, since we found what is the possible controlled variable - i.e. for each frequency it is any sound above the threshold intensity. That is why I think this experiment is no more than the TCV. The experiment is not useless or invaluable, but it does not speak about input function. Well, perhaps we could say it tells us what the lower limit of the input function is, if that makes sense.

BA: You’re right – the procedure does not yield a mathematical function relating the intensity of a sound wave to the amplitude of the perceptual signal. But it does give us important information about that function, namely the lower limits of intensity that must be exceeded if the sound it to be perceived at all, and how those limits vary with frequency.

Bruce, you mentioned difference thresholds. They are a different beast. They might give more information about control of difference between two intensities. I won’t rush with conclusions. What properties of the control loop, on what levels, would you say are related to the difference limen?

BA: Difference thresholds indicate the limits of difference below which two perceptions cannot be distinguished – whatever the level of the perception. If you were asking a person to keep two perceptions “the same” (i.e., keep their difference at zero), the person would perceive that difference as zero when it fell below the difference threshold, even though the physical difference between the two inputs was not necessarily zero. But as Fechner demonstrated, one can use difference thresholds to construct an actual input function relating the intensity of a sound wave to its perceived loudness. (By the way, in that function, the zero-point falls at the absolute threshold for intensity – that’s how the absolute threshold factors in to the mathematical function.)

MT:
The other problem is with how the higher levels of perception are constructed from signals from lower levels. The perception of “relationship between finger and sound” is constructed from perceptions of finger position and intensity of tone, so intensity of tone can’t be an uncontrolled perception - perhaps its reference is changed after rising the finger. Or gain?

Why can’t it be an uncontrolled perception? Lots of the inputs to any higher-level perception are unconrtrolled. Why do you have a problems with that?

AM:

I have problems with this because I don’t know how to make a model that would pick and choose different perceptions to control or not control, so I don’t know how that would work, and I’m confused what even means “an uncontrolled perception”.

BA: How the brain picks and chooses different perceptions to control is a question not addressed in Bill’s HPCT proposal, although Bill did speculate that it had something to do with attention/awareness. It’s a question left to be addressed by future research. But it’s definitely something we do all the time. Right now I’m controlling the positions of my fingers in order to type the words you are now reading, but I am not controlling what words you wrote in your post, words that I am now reading. (To read them I must control where I am looking, etc., but that is not the same as controlling what you wrote, as I perceive it.)

AM: In a standard tracking task like the TrackAnalyse, one of the sticks is moving as the reference, one of them is moving as the cursor. The reference stick is not ‘under control’. It is not even perceived on this level. The cursor stick is also not ‘under control’ on this level. We have found out that what is under control can can be approximated by a function: difference = cursorPosition - referencePosition. That is an approximation of what is under control, and a very good one, since we get good RMS and correlation measures.

BA: I was going to use the same example to distinguish between controlled versus uncontrolled perceptions. Where the target appears on the screen is not under your control; the computer program “decides” that. What is under your control is the cursor position, which you control by moving the mouse.

BA: Of course there are certain things about your perception of the target that you can control, should you choose to. You can make the target invisible by closing your eyes, or blurry by squinting or putting on the wrong pair of glasses. You can move the image of the target to a different part of your retinas by looking slightly away from the target, so that you see it “out of the corner of your eyes.” Perhaps this is the source of your confusion about whether a perception is controlled or not. The crucial distinction is that the position of the target on the screen is not under your control. Your perception of the target has many dimensions. It is not sufficient to say that the target is not under your control; we have to specify what aspect of the target is not under control.

BA: The demo in LCS III called “ChooseControl” was designed to illustrate this point. While you are controlling, say, the shape of the ball, you are simultaneously failing to control its position on the screen and the tilt of its axis. In fact, the computer is even able to determine which aspect you were controlling and which aspects you were not.

Is there really a perception of cursor position as a neural magnitude and another perception of ‘reference stick position’, and then a neuron that takes a difference between those two? There could be, and that would mean the retina has some sort of coordinate system and tracks positions of objects relative to something else.

There could also be a function that directly perceives this difference as the length of an invisible stick that comes between the cursor and the reference. Perhaps this perception of difference is related to time that it takes eyes to focus from one stick to another. Perhaps it is related to eye muscle effort in moving from one position to another. Or both of those things. I don’t know, the visual system is very complex, as is the auditory system. I don’t think we can just say, ‘this is clearly an uncontrolled perception’.

BA: That’s an excellent point. I’m not sure how one could distinguish which perception is the one actually being controlled, since mathematically they come to the same thing – an error signal proportional to the difference in position between cursor and target. But perhaps we can approach this from a different angle. Do you perceive the target and the cursor as separate entities on the screen, possessed of their own motions and other properties (color, length, etc.). Or do you (only) perceive an imaginary line stretching between the two positions? Because we do perceive the former, it seems likely to me that the latter, if present at all, must be generated further “upstream” in the visual system – and isn’t that what it means to perceive the difference in position?

BA: Be that as it may, in either case you have control only over one aspect. If you are controlling based on perceptions of the relative positions of target and cursor, you can only move the cursor; the target position is not under your control. If you are controlling the length of an imaginary line stretching between the two, you can only change the position of one end of that line (the end terminating at the position of the cursor); the position of the other end (terminating at the position of the target) is not under your control.

Bruce

p.s. Your speculation about whether positional differences might be detected via changes in focus or eye muscle effort puts you in some very good company – that of early researchers investigating various visual illusions such as the “inverted T illusion” and the Muller-Lyer illusion. The origins of many fascinating visual illusions are still a matter of scientific research and debate.

[From Adam Matic 2014.03.17 1645 cet]

Bruce Abbott (2014.03.18.0945 EDT)
BA: But as Fechner demonstrated, one can use difference thresholds to construct an actual input function relating the intensity of a sound wave to its perceived loudness. (By the way, in that function, the zero-point falls at the absolute threshold for intensity – that’s how the absolute threshold factors in to the mathematical function.)

AM:
What the subject is controlling is the difference between two intensities, as in the method of adjustment. Would you say that the various difference thresholds are related to the gain of this difference controlling system?
I mean, if the gain of this system is low, then it won't find small differences. If it is high, it will find very small differences.

BA: I was going to use the same example to distinguish between controlled versus uncontrolled perceptions. Where the target appears on the screen is not under your control; the computer program “decides” that. What is under your control is the cursor position, which you control by moving the mouse.

AM:
I don't think that position of the cursor _on the screen_ is a controlled variable.
"Position of the cursor on the screen" is a computer variable related to the coordinate system of the screen, as is the "position of the target on the screen", as is the "difference between positions of target and cursor". Those are quantities in the model of the environment. The perceptual signal of the model is inputGain*positionDifference, and only this quantity is what is being controlled by our model control system. The system is varying position of the handle, which is related to the cursor position and disturbance variables, which is related to the position difference variable. All the variables in the last sentence are parts of the environment of the model control system.
That would make _retinal position_ of the target stick a controlled and perceived variable as much as _retinal position_ of the cursor stick. Hypothetically, both are being controlled by some eye-focusing-on-object system, or a different type of position-difference-producing function. Nevertheless, they are both controlled variables. Experimentally supported is only the hypothesis that the controlled variable is this difference between their position.

BA: p.s. Your speculation about whether positional differences might be detected via changes in focus or eye muscle effort puts you in some very good company – that of early researchers investigating various visual illusions such as the “inverted T illusion” and the Muller-Lyer illusion. The origins of many fascinating visual illusions are still a matter of scientific research and debate.

AM:
Thanks, but these are hardly my own ideas. I picked them up in various places when reading about the visual system, perhaps about the visual illusions. A very surprising source is H. Poincare's book Science and Method - there is a chapter about how human-invented geometry relates to 'outside reality'. Or was the book Science and Hypothesis. I'm not sure, they are available as pdf files somewhere online.
Adam

[From Rick Marken (2014.03.18.1015)]

···

Bruce Abbott (2014.03.17.1050 EDT)–

RM: I don’t think Bruce and Martin, the main defenders of the S-R approach to research, are “impure”. I think they are simply wrong.

BA: When you describe Martin and I as “defenders of the S-R approach to research” the reader might get the impression that we are promoting “S-R research” in opposition to PCT. Of course we are doing nothing of the kind.

RM: What are you doing then? I have never heard either one of you guys doing anything other than try to interpret the methodology used and results obtained in conventional psychology experiments in terms of PCT. Or trying to find a place for conventional S-R research in the context of a PCT view of the world (it seems to me that that was what the “uncontrolled perceptions” thing was about, for example). This is what I call defending the S-R approach to research. You are defending, by couching it in PCT terminology, an approach to research that was done in ignorance of the fact that organisms are perceptual control systems; an approach that, as per Powers’ Psych Review paper, is either misleading (per the behavioral illusion), ignores the existence of controlled variables or both.

RM: PCT research is aimed at discovering the perceptual variables that organisms control; the variables around which their observed behavior is organized. The goals and methods of this research differ considerably from those of the S-R approach. So I would imagine that if you really were interested in promoting the PCT rather than the S-R approach to research you would promote the PCT approach, which involves testing for controlled variables.

BA: Interesting that you think that what we have been doing “is impeding . . . the development of a PCT-based science of life.”

RM: I think you are impeding it only in the sense that you are both in a position to make a substantial contribution to promoting the PCT approach. You are both scientific psychologists – and there are precious few of us involved in PCT – with some considerable cachet in the field; you, Bruce, with your Research Methods textbook in its Nth edition and Martin with many notable accomplishments in the area perceptual psychology (I was on the verge of using his PEST adaptive threshold technique as part of my thesis research back in the early 1970s; I knew of Martin Taylor well before I knew of PCT). And you are both obviously very smart and talented. If you guys would actively explain and demonstrate the approach to research described by Bill in the 1978 Psych Review paper I think it would go a long way toward launching the PCT revolution that Bill was hoping might start before he passed away. So you are certainly not actively impeding the development of a PCT; but I think you are passively impeding it by devoting so much effort to defending the status quo.

BA: I can’t speak for Martin, but for my part, I see some of your efforts as serving to impede the development of PCT, even though I know that this is exactly the opposite of your intention. When you present arguments or assertions that are demonstrably untrue, you damage the credibility of PCT in the eyes of those who know better.

RM: I’m sure I have made mistakes but I think I have been willing to acknowledge and correct them – sometimes too willing, as was the case recently with measuring characteristics of I/O components in a loop. But maybe you could give me examples of arguments or assertions that I have made (and am still making) that are demonstrably untrue.

BA: I know that you have only the best intensions, Rick, but raising objections and criticisms that are based on a faulty understanding of certain principles does nothing to help the PCT cause, and may hurt it.

RM: Please tell me what objections and criticisms I have made that are based on faulty understanding of certain principles. What are the principles that I have a faulty understanding of?

BA: We’re working toward the same objective, but unfortunately we seem to have very different views as to whether discussing such things whether one can get valid data about input functions from “S-R” experiments is helping or hindering the future of PCT.

RM: And apparently my view is wrong? I would be interested in hearing what you think my view is and why you think it’s wrong.

Best regards

Rick


Richard S. Marken PhD
www.mindreadings.com
It is difficult to get a man to understand something, when his salary depends upon his not understanding it. – Upton Sinclair