All Stimuli are Disturbances

In order for a stimulus to elicit a response it seems to me it must disturb our control of some variable, it must create a discrepancy between the reference condition for that variable and our perception of that variable. If it didn’t there would be no action on our part. So, it seems to me that the subject line is true; namely, that in terms of control theory all stimuli are disturbances.

Comments?

Regards,

Fred Nickols, CPT

Managing Partner

Distance Consulting LLC

The Knowledge Workers’ Tool Room

Kindle Book: Tools for Knowledge Workers

[From Bruce Abbott (2013.07.07.1150 EDT)]

Fred Nickols:

FN: In order for a stimulus to elicit a response it seems to me it must disturb our control of some variable, it must create a discrepancy between the reference condition for that variable and our perception of that variable. If it didn’t there would be no action on our part. So, it seems to me that the subject line is true; namely, that in terms of control theory all stimuli are disturbances.

FN: Comments?

The term “stimulus” has two different but related definitions. First, in a reflex, the stimulus is defined as “that which elicits the reflexive response” (and the response as that which is elicited by the stimulus). Such a stimulus is a sensed change in a controlled perception that is produced by a disturbance to that perception. (In reflexes the change is usually sudden – a step function – followed by a quick response.) A disturbance initiates the change in the value of the input, but I question whether the disturbance itself should be labeled as the stimulus, although it frequently is. For example, in the classic knee-jerk reflex, the strike of the doctor’s little rubber hammer on the patellar tendon is usually described as the stimulus, but the real stimulus in that case is the rapid stretching of the muscle as sensed by the muscle spindles; the system controlling muscle length experiences a disturbance that it attempts to correct by increasing the force exerted by the muscle. By then the stretching effect of the hammer’s impact is over and the counteracting contraction occurs too late to oppose it; consequently the leg kicks upward.

The second definition of “stimulus” is “that which stimulates a sensory receptor.” This definition includes the stimulus of the reflex but is broader. For example, electromagnetic radiation in the right range of wavelengths stimulates the photoreceptors in the retina of the eye, and thus is a stimulus according to this second definition. Such stimulation may be continuous or intermittent, steady or variable, and may or may not serve as input to a control system. If it doesn’t, changes to it would not qualify as disturbances. We are almost continuously exposed to varying patterns of visual stimulation, but most of those changes taking place at any given moment do not disturb any controlled perceptions.

Bruce

[From Rick Marken (2013.07.07.0900)]

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On Sun, Jul 7, 2013 at 4:17 AM, Fred Nickols fred@nickols.us wrote:

FN: In order for a stimulus to elicit a response it seems to me it must disturb our control of some variable, it must create a discrepancy between the reference condition for that variable and our perception of that variable. If it didn’t there would be no action on our part. So, it seems to me that the subject line is true; namely, that in terms of control theory all stimuli are disturbances.

Comments?

RM: You kind of answered your question yourself in your first sentence, Fred: In order for a stimulus to elicit a response it must be a disturbance to a controlled variable. If a person is not controlling a variable to which the stimulus would be a disturbance (requiring a compensating response) then the stimulus is not a disturbance. So not all stimuli are disturbances. It’s better, I think, to say that all stimuli are potential disturbances; they are disturbances when a system is controlling a variable which would be affected (disturbed) by the stimulus. So smiling at someone you pass on the street would be a disturbance only to a person who is controlling for being sociable and would probably “elicit” a smile or nod back; such a would be irrelevant to someone who is not controlling being sociable. Same stimulus (smile) but a disturbance in one case but not in the other.

Best

Rick


Richard S. Marken PhD
rsmarken@gmail.com
www.mindreadings.com

[From Fred Nickols (2013.07.07.1331 EDT)]

Hmm. Reading between the lines it seems what you say confirms what I said. If no response is elicited, i.e., no action, then the stimulus isn’t a stimulus. It seems to me that, by definition, a stimulus elicits a response, i.e., some action. If I’m missing something, please try again. I can be dense at times.

Fred

···

From: Bruce Abbott [mailto:bbabbott@FRONTIER.COM]
Sent: Sunday, July 07, 2013 11:52 AM
To: CSGNET@LISTSERV.ILLINOIS.EDU
Subject: Re: All Stimuli are Disturbances

[From Bruce Abbott (2013.07.07.1150 EDT)]

Fred Nickols:

FN: In order for a stimulus to elicit a response it seems to me it must disturb our control of some variable, it must create a discrepancy between the reference condition for that variable and our perception of that variable. If it didn’t there would be no action on our part. So, it seems to me that the subject line is true; namely, that in terms of control theory all stimuli are disturbances.

FN: Comments?

The term “stimulus” has two different but related definitions. First, in a reflex, the stimulus is defined as “that which elicits the reflexive response” (and the response as that which is elicited by the stimulus). Such a stimulus is a sensed change in a controlled perception that is produced by a disturbance to that perception. (In reflexes the change is usually sudden – a step function – followed by a quick response.) A disturbance initiates the change in the value of the input, but I question whether the disturbance itself should be labeled as the stimulus, although it frequently is. For example, in the classic knee-jerk reflex, the strike of the doctor’s little rubber hammer on the patellar tendon is usually described as the stimulus, but the real stimulus in that case is the rapid stretching of the muscle as sensed by the muscle spindles; the system controlling muscle length experiences a disturbance that it attempts to correct by increasing the force exerted by the muscle. By then the stretching effect of the hammer’s impact is over and the counteracting contraction occurs too late to oppose it; consequently the leg kicks upward.

The second definition of “stimulus” is “that which stimulates a sensory receptor.” This definition includes the stimulus of the reflex but is broader. For example, electromagnetic radiation in the right range of wavelengths stimulates the photoreceptors in the retina of the eye, and thus is a stimulus according to this second definition. Such stimulation may be continuous or intermittent, steady or variable, and may or may not serve as input to a control system. If it doesn’t, changes to it would not qualify as disturbances. We are almost continuously exposed to varying patterns of visual stimulation, but most of those changes taking place at any given moment do not disturb any controlled perceptions.

Bruce

[From Fred Nickols (2013.07.07.1334 EDT)]

Hmm. If a stimulus is that which elicits a response then anything that doesn’t elicit a response is not a stimulus. Further, because a stimulus does elicit a response, it has to be a disturbance. If it didn’t disturb a controlled variable it wouldn’t elicit a response and therefore wouldn’t be a stimulus.

If I’m missing something, please try again.

Fred

···

From: Richard Marken [mailto:rsmarken@GMAIL.COM]
Sent: Sunday, July 07, 2013 12:07 PM
To: CSGNET@LISTSERV.ILLINOIS.EDU
Subject: Re: All Stimuli are Disturbances

[From Rick Marken (2013.07.07.0900)]

On Sun, Jul 7, 2013 at 4:17 AM, Fred Nickols fred@nickols.us wrote:

FN: In order for a stimulus to elicit a response it seems to me it must disturb our control of some variable, it must create a discrepancy between the reference condition for that variable and our perception of that variable. If it didn’t there would be no action on our part. So, it seems to me that the subject line is true; namely, that in terms of control theory all stimuli are disturbances.

Comments?

RM: You kind of answered your question yourself in your first sentence, Fred: In order for a stimulus to elicit a response it must be a disturbance to a controlled variable. If a person is not controlling a variable to which the stimulus would be a disturbance (requiring a compensating response) then the stimulus is not a disturbance. So not all stimuli are disturbances. It’s better, I think, to say that all stimuli are potential disturbances; they are disturbances when a system is controlling a variable which would be affected (disturbed) by the stimulus. So smiling at someone you pass on the street would be a disturbance only to a person who is controlling for being sociable and would probably “elicit” a smile or nod back; such a would be irrelevant to someone who is not controlling being sociable. Same stimulus (smile) but a disturbance in one case but not in the other.

Best

Rick


Richard S. Marken PhD
rsmarken@gmail.com
www.mindreadings.com

[From Rick Marken (2013.07.07.1100)]

[Fred Nickols (2013.07.07.1331 EDT)]

Hmm. Reading between the lines it seems what you say confirms what I said. If no response is elicited, i.e., no action, then the stimulus isn’t a stimulus. It seems to me that, by definition, a stimulus elicits a response, i.e., some action. If I’m missing something, please try again. I can be dense at times.

I presume this is reply to my comments. If so, you are right Fred! I was saying that all stimuli are potential disturbances because a stimulus won’t elicit a response if there is no controlled variable to which it is a disturbance. But then, it’s not a stimulus. So you are correct to say that all stimuli are disturbances! It’s a tautology. What I should have said is that all environmental variables are potential stimuli; but they are only stimuli if they are disturbances to controlled variables.

Best

Rick

···


Richard S. Marken PhD
rsmarken@gmail.com
www.mindreadings.com

[From: Richard Pfau (2013.07.07.1444 EDT)]

If we focus on the definition of stimuli as “that which stimulates a sensory receptor” given by Bruce Abbott (2013.07.07.1150 EDT)], then it seems that (a) some stimuli are disturbances and (b) some stimuli are not.

In the case of (a), stimuli that are disturbances affect a control system and controlled variables, as others have pointed out.

In the case of (b) it seems that some stimuli are not disturbances. For example, take the case of stimuli that passively result in learning but not reorganization, such as when we see something a number of times and later remember having seen that something when we see it again (such a person’s face), or when we hear something a number of times and hearing it again, later remember having heard it before (such as a bird’s song or a tune on the radio). In other words, it seems that some stimul may affect learning (neural organization) without necessarily affecting a control system and controlled variable.

···

-----Original Message-----

From: Fred Nickols fred@NICKOLS.US

To: CSGNET CSGNET@LISTSERV.ILLINOIS.EDU

Sent: Sun, Jul 7, 2013 7:24 am

Subject: All Stimuli are Disturbances

In order for a stimulus to elicit a response it seems to me it must disturb our control of some variable, it must create a discrepancy between the reference condition for that variable and our perception of that variable. If it didn’t there would be no action on our part. So, it seems to me that the subject line is true; namely, that in terms of control theory all stimuli are disturbances.

Comments?

Regards,

Fred Nickols, CPT

Managing Partner

Distance Consulting LLC

The Knowledge Workers’ Tool Room

Kindle Book: Tools for Knowledge Workers

[Bruce Abbott (2013.07.07.1622 EDT)]

Fred Nickols (2013.07.07.1331 EDT)

FN: Hmm. Reading between the lines it seems what you say confirms what I said. If no response is elicited, i.e., no action, then the stimulus isn’t a stimulus. It seems to me that, by definition, a stimulus elicits a response, i.e., some action. If I’m missing something, please try again. I can be dense at times.

Not according to the second definition of “stimulus” I mentioned in my post . . . Perhaps that’s what you missed?

Bruce