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27 Feb 2013

Merleau-Ponty, Ch1.2.1 The Structure of Behavior, “The Stimulus”, summary

by Corry Shores
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[All boldface and underlining is my own. Citations give English translation pages first, then the French ones. Text in brackets is my own commentary.]



Merleau-Ponty


The Structure of Behavior
La structure du comportement


Ch.1
Reflex Behavior
La comportement réflexe


Subsection 2
The Classical Conception of the Reflex and Its Auxiliary Hypotheses
La conception classique du réflexe et ses hypothèses auxiliaires


Sub-subsection 1
The ‘stimulus’
Le ‘stimulus’





Very Brief Summary:

An organism must process holistically its stimuli to know how to respond, and it also plays a productive role in the formation of that stimuli, by altering its own form of receptivity, which as well can alter the form not just of how the stimuli is received but also it can alter the form of the behavior of the thing stimulating it. This influence can be mutual, making the causal relation circular.


Brief Summary:

The organism’s reflexes respond always to complex stimuli. The classical approach analyzes the stimuli into simple stimulus-response mechanical triggers, such that the whole response is the simple sum of all the smaller direct mechanical reactions. However, many actual animal responses do not fit this description. Quantitatively different stimuli of the same sort can have very qualitatively different responses, for example. A holistic model is better. The organism on the one hand waits to discern a more complex pattern before responding, and also it changes its manner of receiving the stimulus simultaneously with its affection. So (1) responses to stimuli involve processing that information at a higher ‘computational’ level, and (2) part of this process involves the sensing organism self-modifying the form of its receptivity-behavior so to influence the form of the stimulus input. This can also influence the behavior of other organisms it might be sensing. Thus response behaviors are fundamentally complex and the responding organism is in a circular causal relation with the world stimulating it.


Summary


The stimulus has spatial arrangements, rhythms, and rhythms of intensity. It also has elementary properties. The action of the stimulus on the organism comes more from its arrangements and rhythms than from its properties. Merleau-Ponty goes on to quote Sherrington and Miller, who describe how stimuli with different structures are applied to the same nerve locations and yet evoke different responses [implying that the reflex response is not a direct mechanical response to the stimulus but rather involves computational processing that recognizes patterns of stimulation.]

Five different reflex responses can be obtained by stimulating the ear of a cat depending on the structure of the excitant employed. The pinna of the ear flattens out when it is bent, but responds to tickling with a few rapid twitches. The character of the response is completely modified depending on the form of electrical excitation (faradic or galvanic) or its strength; for example, weak strengths evoke rhythmic responses; strong ones evoke tonic reflexes. A decerebrate cat [swallows] water as soon as it is placed in the pharynx; but water to which a few drops of alcohol has been added provokes a doubling-up response and movements of the tongue (Sherrington and Miller). [qtd in Merleau-Ponty English translation p.11 /  French p.9]

The classical conception of nerve stimulus response is to break down the complexity of both the stimulus and the response into elementary processes, which are

composed of a stimulus and a response which were always associated in experience. || For example, the action of the scratching stimulus would be analyzed into as many partial actions as there are anatomically distinct tactile receptors in the ear. The twitching of the ear which responds to this excitant would be resolved in turn into a certain number of elementary contractions. In principle, to each part of the stimulus there should correspond a part of the reaction. And the same elementary sequences, combined differently, should constitute all the reflexes. The qualitative properties of the situation and those | of the response—that which makes the difference for consciousness between scratching and bending the ear of the animal, between a twitching of this ear and a retraction movement—should, if the same receptors are really affected in both cases, be reducible to diverse combinations of the same stimuli and of the same elementary movements. (11|12 / 9||10)

[So perhaps, in the classical approach, bending the cat’s ear would be broken down into tiny motions touching nerve endings that mechanically trigger certain muscle contractions causing the ear to flatten, and were the stimulus instead a tickling, different sorts of elementary motion stimulations would affect different nerve endings altogether, which themselves mechanically trigger different muscle contractions, causing the ear to twitch. I am uncertain, but Merleau-Ponty seems to be saying that instead of any one nerve ending being stimulated differently by different stimuli, that instead different stimuli stimulate different nerve endings, but only the ones sensitive to that particular kind of sensation; and, no processing of the information is needed in the brain, because that selective activity is performed on the level of sensitivity (this interpretations seems to correspond to what he says at the end of this section).]

It is absolutely excluded that an organic substrate could fulfill truly different functions in turn and that the reaction could change in nature because of a simple difference in the rhythm of excitations applied in turn to the same apparatuses. (12 / 10)

Yet, this method of decomposing into elementary reactions does not work for the the sorts of behaviors Merleau-Ponty was describing before. He cites two examples. Recall that “A decerebrate cat [swallows] water as soon as it is placed in the pharynx; but water to which a few drops of alcohol has been added provokes a doubling-up response and movements of the tongue”. But when we mix water and alcohol, we do not have a chemical reaction that results in a new substance. [If the classical approach were right, then there should have still been a reaction to the water, a swallowing to some degree, because the water did not go away when the alcohol was added. Thus information about the stimulus was processed not through direct mechanisms but rather through some sort of neural processing.]

the action of water with a few drops of alcohol on the decerebrate cat cannot be understood in terms of the action of the pure water nor of that of the pure alcohol. On the other hand, water and alcohol do not constitute a chemical combination which could exercise a different action than that of the components. It is within the organism then that we will have to look for that which makes a complex stimulus something other than the sum of its elements. (12 / 10)

Previously Merleau-Ponty wrote:

In case of competition of stimuli it is the form much more than the nature, the place or even the intensity of the excitation which determines the resulting reflex. A painful excitation of the penis, even if it is weak, inhibits the reflex of erection. A simple touch immobilizes the spinal snake (Luchsinger), while stronger cutaneous excitations evoke very different responses. (11 / 9)

Merleau-Ponty’s second example for a case where the classical approach fails is this snake response. [We cannot say the responses are the addition of smaller ones, because there is too much variety in the response compared to the relatively much less variety in the stimulus. Also this case might be one where a threshold in quantitative variation in the stimulus is crossed, causing a qualitative change in response, which cannot be explained on the basis of the addition of component mechanical triggers.)

In the same way the inhibiting effect of a cutaneous contact on a spinal snake cannot be understood as a simple algebraic addition of the excitations which it provokes and of those which, on the other hand, provoked the crawling movement. If the most frequent observations are considered, there is no basis for treating the reactions which we will call qualitative as appearances, and the reactions which conform to the reflex theory as exclusively real. (12 / 10)


Now even though there is internal processing of the stimulus information, this does not mean that Merleau-Ponty is relying on some sort of mentalism, because all this complex behavior can still be explained in mechanistic terms. [Consider how a piano keyboard can make very different musics and noises depending on the precise “form” of the stimulus, that is, the “order and the cadence of the impulses received.” Also consider how our speech patterns have a temporal order and also a spatial one, perhaps the size of the sound waves, which correlates with their frequency. What the phone transmits depends upon variations of these parameters. This is not necessarily an analogy for the above examples. It is merely showing that temporally varying patterns of input for keyboards and phones produce many various output responses. There are “forms” coming in, and the machine responds to it. Complex variations in the form of the input cause complex variations in the response.]

A keyboard is precisely an apparatus which permits the production || of innumerable melodies, all different from each other depending on the order and the cadence of the impulses received; the extent to which the metaphor of the keyboard has been used in the physiology of the nerve centers is well known. An automatic telephone is even more clearly an apparatus which responds only to excitants of a certain form and modifies its responses according to the spatial and temporal order of the stimuli. (12 / 10||11)

But these machines only respond mechanically in direct response to their inputs. The forms of their response then originate not in their processing of the information but rather in the organism using the machines.

But do the constellations of excitants act on the organism as the fingers of the pianist act on the instrument? Nothing is ever produced in the piano itself but the separate movements of the hammers or the strings; it is in the motor system of the performer and in the | nervous system of the auditor that the isolated physical phenomena, of which the piano is the seat, constitute a single global phenomenon. And it is there that the melody truly exists in its sequence and characteristic rhythm. (12|13 / 11)


What makes the difference between organisms and such machines as these is that organisms contribute to the form of the output [while the machines have just a simple functional assignment of input variations to output variations. Consider Edwards and Penney’s machine illustration of mathematical functions. For the function f(x) = y, for whatever x is inputted into the machine, some determinate y is given as output.

(From Edwards & Penney, pp.2-3)

The keyboard or phone has its own predetermined assignment functions, for example louder talking makes stronger electrical current and thus stronger sound at the other phone receiver, or higher pitch of sound becomes higher frequency of electrical current, meaning higher frequency sound output. Or also in this case of the phone, different sequences of dialed numbers or letters (sequences which are interpreted as a whole and not number-by-number) will connect the line to different locations. Organisms are machines that also respond to the complex forms of inputs with complex output behaviors, however there is not a direct mechanical functional assignment for inputs and outputs such that the output is the simple sum of the inputs. This is because the input information must be internally processed so that the proper reaction is given.] Merleau-Ponty writes:

The organism cannot properly be compared to a keyboard on which the external stimuli would play and in which their proper form would be delineated for the simple reason that the organism contributes to the constitution of that form. (13 / 11)

[The reason he seems to give for this is not just that the organism has internal processing, but also that the inputs coming in are already modified by output behaviors. So in a way, an organisms preforms the input with responses that are simultaneous with the stimuli. But how does this explain the example of the cat ear? Does this imply that the cat’s ear turns flat when bent, and twitches when tickled, because it changed its comportment toward the stimuli, its way of receiving the stimuli?] [Merleau-Ponty then gives an example of capturing an animal with some device, perhaps this could be like a net or fishing line.] He writes:

When my hand follows each effort of a struggling animal while holding an instrument for capturing it, it is clear that each of my movements responds to an external stimulation; but it is also clear that these stimulations could not be received without the movements by which I expose my receptors to their influence. ". . . The properties of the object and the intentions of the subject . . . are not only intermingled; they also constitute a new whole.” (13 / 11; the quotation is cited as “Weizsäcker, Reflexgesetze, p.45. “L’organisme est, dit Weizsäcker, Reizgestalter.” [Note: Reizgestalter is misspelled as Reizgestaller in the English translation.])

Quand ma main, tenant un instrument de prise, suit chaque effort de l’animal qui se débat, il est clair que chacun de mes mouvements répond à une stimulation externe, mais clair aussi que ces stimulations ne pourraient être recueillies sans les mouvements par lesquels j’expose mes récepteurs à leur influence. « (……) Les propriétés de l’objet et les intentions du sujet (……) non seulement se mélangent, mais encore constituent un tout nouveau. » (11)

[So here he seems to be saying that his movements are doubly both reactions to the forms of stimuli while as well being productions of those very same forms of stimuli. One interpretation of this text concerns merely the receiver and its influence over its own way of receiving the stimulus. Because we will later examine Andy Clark’s treatment of this example, we will use his particular illustration, a hamster in tongs. So according to the first interpretation (a): we catch a hamster with tongs, and for example it lengthens itself so its body narrows to slip out of the grips. Our hands sense the decrease in the animal’s width, and we tighten our hold so to keep it captured. But consider if we had never changed the strength of our hold. The hamster would have slipped out, and then we never would have tightened our hands in the first place, because we would not have felt its body changing shape. So the tightening of our grip was both simultaneously the cause for us being able to sense the hamster narrowing while at the same time being our response to its narrowing. The second interpretation would say that in fact our simultaneous or advance response causally modifies the stimulus source itself: (b) The hamster increases its narrowing in response to our tightening, and we increase our tightening in response to the hamster’s narrowing. This interpretation is more concerned with the reciprocal causality each organism has on the other’s behavior. The first interpretation however was only concerned with how one organism’s self-modifying reactions to a stimulus are in the same stroke productions of that very stimulus it is reacting to. This example alone seems to support the first interpretation. Merleau-Ponty writes: “each of my movements responds to an external stimulation; but it is also clear that these stimulations could not be received without the movements by which I expose my receptors to their influence.” The second interpretation would need this to read “…these stimulations would not have been generated by the animal’s behavior without the movements by which I affect its behavior. Also, what is important for the second interpretation is that the thing being sensed be something capable of having its own behavior be modified through our own interaction with it, especially our own perceptive interaction with it. The second interpretation would not apply then to cases when we are perceiving something inert or acting independently of our behavior. Yet as we will see, the following examples deal with objects more of this non-animal sort, so it would seem very likely that the second interpretation is inaccurate. The reason we address this other interpretation is because it seems to be the one Andy Clark gives for this passage in his book Being There, which we will turn to in a forthcoming post.]We consider another example, and this one more clearly supports the first interpretation we mentioned above in brackets. Consider when our eyes follow something in our vision, let’s say something catches our eye and we look to it. The interesting thing can be said to cause our eyes’ behavior of moving toward it, however, we would not have noticed it in the first place had we not already moved our eyes into its vicinity, and had been in a mode of visual attentiveness to such visual stimuli [for we could have been pondering on something so deeply we noticed nothing in our field of vision.]

When the eye and the ear follow an animal in flight, it is impossible to say "which started first" in the exchange of stimuli and responses. Since all the movements of the organism are always conditioned by external influences, one can, if one wishes, readily treat behavior as an effect of the milieu. But in the same way, since all the stimulations which the organism receives have in turn been possible only by its preceding movements which have culminated in exposing the receptor organ to the external influences, one could also say that the behavior is the first cause of all the stimulations. (13 / 11)


We have a manner of offering our sensitivities to the stimuli we sense, and this manner ‘creates’ the form of the stimuli we are responding to. We react to stimuli, but we choose the stimuli we react to on the basis of the properties of that stimuli. Thus the equivalent for the keyboard example would be like a mechanical hammer falling at a steady rate, and the keyboard moving itself underneath so to produce some more complex melody.

Thus the form of the excitant is created by the organism itself, by its proper manner of offering itself to actions from the outside. Doubtless, in order to be able to subsist, it must encounter a certain number of physical and chemical agents in its surroundings. But it is the organism itself—according to the proper nature of its receptors, the thresholds of its nerve centers and the movements of the organs—  || which chooses the stimuli in the physical world to which it will be sensitive. “The environment (Umwelt) emerges from the world through the actualization or the being of the organism—[granted that] an organism can exist only if it succeeds in finding in the world an adequate environment.” This would be a keyboard which moves itself in such a way as to offer—and according to variable rhythms—such or such of its keys to the in itself monotonous action of an external hammer. (13 / 11||12)


[Consider how a telephone seemed to have worked in Merleau-Ponty’s time, what he is calling a téléphone automatique. It seems that you dialed not a number but rather the name of the person you are calling, although perhaps a number was still needed for further determination of the receiving party. If we were sticking with the classical approach, we would only note that dialing an O mechanically triggers a predetermined response, and all the other letters their own responses. Yet there are many letters in the name but only one destination for the call, so the whole sequence of letters must be regarded more holistically as a stimulus rather than a sum of independent stimuli. There is what seems to be a processing center (central automatique) in between phones that determines the proper channel for the call signal to be sent through. As we noted, a dialed O only causes a response in the context of its fellow letters, and different combinations including that O will result in different channels being connected. So this example seems to support our earlier interpretation of Merleau-Ponty’s theory of stimulus response, which is that there is a neural processing part of the system that deals with the information more in a holistic synthetic way rather than as a simple sum of mechanical triggers. So consider the two cases of dialing either Oberkampf or Botzaris. There is an O next to a B in both cases. From the phone to the automatic central, there is a simple mechanical response relation; each dialed letter on the phone results in a letter registering at automatic central. However at this processing center, the overall behavior of choosing the proper channel involves the central waiting for all stimuli to come in, then see their arrangement. What matters here is the order, whether B comes before or after O. This explanation gets a bit more unclear with the next example that he says is the same situation. We are now to consider looking at a painted panel with concentric solid circles, with the larger one being solidly rose-colored and the smaller inner one being solidly blue-colored. Merleau-Ponty says that this painting can appear two different ways depending on the relations we see the circles having to one another. So if we see the  rose circle as the background, then the blue disc appears as if standing atop the red beneath it. Or we might instead see the red circle primarily and the blue one is like a hole in the red one. Consider a familiar example, the Rubin’s vase illusion.


Rubin's Vase

(
layersmagazine.com. Thanks Jacob Cass)


(Thanks
wikipedia)

Our seeing either a vase or a pair of faces would be our response. This depends a lot on how we are choosing to see the image, how we are comporting ourselves toward it. If we change our sensitivities so to see it as a vase, the visual stimuli likewise are more apt to evoke in us the response of seeing a vase. Merleau-Ponty then makes things even less clearly consistent with his next example. He seems to be having us consider a keyboard that is analogous to the central automatic. So a hammer will hit a certain key in a certain way, then the keyboard machine decides on putting some other keyboard under the hammer for the next hit; I presume this keyboard rotation continues depending on the hits to follow. Perhaps this is like how if we dial a B first, the central automatic, knowing that only a limited set of second letters can come next (as there are no names beginning BN for example), becomes sensitive for only certain letters. It will not register an N coming next, because it is not geared for that stimulus. Let’s try to apply this to the previous example of the cat ears, as he seems to trying to explain the mechanics of it. The ear will either flatten or twitch, depending if it is bent or tickled. The initial pressure of both motions might be the same. But the brain waits a little for more stimuli, which tell it whether the ear will be bent or if it will be tickled. So after the first moment of stimulus, it will be sensitive for a set of forthcoming stimulations but not for others, as it knows these othersnever follow the first sort. Perhaps it no longer becomes sensitive to pulling sorts of motions, and so it changes its movement a little bit, making certain kinds of contractions that allow it to feel this now more limited set of possible forthcoming stimuli. Then as more come, it furthers this process of selection. Or, it waits a little until there is enough to disambiguate the stimulus and provide the proper response.]

The model of the automatic telephone appears more satisfactory. Here indeed we find an apparatus which itself elaborates the stimuli. | In virtue of the devices installed in the automatic central, the same external action will have a variable effect according to the context of the preceding and following actions. An "O" marked on the automatic dial will have a different value depending on whether it comes at the beginning, as when I dial the exchange "Oberkampf," for example, or second, as in dialing "Botzaris." Here, as in the organism, it can be said that the excitant—that which puts the apparatus in operation and determines the nature of its responses—is not a sum of partial stimuli, because a sum is indifferent to the order of its factors; rather it is a constellation, an order, a whole, which gives its momentary meaning to each of the local excitations. The manipulation "B" always has the same immediate effect, but it exercises different functions at the automatic central depending on whether it precedes or follows the manipulation "O," just as the same painted panel takes on two qualitatively distinct aspects depending on whether I see a blue disc on a rose-colored ground or, on the contrary, a rose-colored ring in the middle of which would appear a blue ground. In the simple case of an automatic telephone constructed for a limited number of manipulations, or in that of an elementary reflex, the central organization of the excitations can itself be conceived as a functioning of pre-established devices: the first manipulation would have the effect of making accessible to subsequent ones only a certain keyboard where the latter would be registered. (13|14 / 12)

In further examinations we will see if higher level reactions involve predetermined responses to particular stimuli. [But here at the lower level of simple reflexes, we see that the response is not a product of a real-time mechanical triggering of simple responses, but rather involves a series of temporally distinct stimuli that must be interpreted.]

We will have to examine whether, in reactions of a higher level, it is possible in the same way to make a distinct operation correspond to each stimulus, a visible device to each "factor," or even to relate the function to ideal variables which would be independent. Even at the level of the reflex, it is now certain that the interaction of the stimuli precludes considering || nerve activity as a sum of "longitudinal" phenomena unfolding from the receptors to the effectors and that, as in the automatic central, "transverse phenomena" must be produced somewhere in the nervous system. (14 / 12||13)

The classical attempts at analyzing reflexes into simple isolated stimulus-response parings was not successful; for even the slightest stimulus affects more than one part of the recepter simultaneously. (14d / 13) All stimuli are complex, thus there is little use in finding elementary reactions. Science normally uses quantitative determinations, but the study of stimuli reactions calls even for qualitative determinations; for, Sherrington found that when two stimuli are in competition, it is not necessarily the stronger stimuli but rather the more painful one that presides. But because Sherrington is committed to the classical model, he cannot say that the same receptor can transmit information for pain but rather that there must be different receptors that are responsible for pain sensations. Yet the scientific facts of reflex tell us that stimuli are interpreted within their wider contexts and also that the organism has a circular and not a linear causal relation to the environment it is responding to.

At the very moment that one is obliged to introduce value into the definition of stimulus one actualizes it, so to speak, in distinct receptors. In the theory of nerve functioning everything happens as if we were obliged to submit to the alternative of anthropomorphism or the anatomical conception of the reflex, when perhaps it is necessary to go beyond it. Before any systematic interpretation, the description of the known facts shows that the fate of an excitation is determined by its relation to the whole of the organic state and to the simultaneous or preceding excitations, and that the relations between the organism and its milieu are not relations of linear causality but of circular causality. (15 / 13)



Merleau-Ponty, Maurice. The Structure of Behavior. Transl. Alden L. Fisher. Boston: Beacon Press, 1963.


Merleau-Ponty, Maurice. La structure du comportement. Paris: Presses universitaires de France, 1942 / 1967.


Edwards & Penney: Calculus. New Jersey: Prentice Hall, 2002, p.2a-3c.


Rubin's Vase 1
http://layersmagazine.com/negative-space.html
Thanks
Jacob Cass


Rubin's Vase 2
http://en.wikipedia.org/wiki/File:Rubin2.jpg

26 Feb 2013

Andy Clark. 8.6 of Being There, “Continuous Reciprocal Causation”, summary


summary by
Corry Shores
[
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[My own commentary is in brackets. All boldface and underlining is my own.]



Andy Clark

Being There:
Putting Brain, Body, and World Together Again

Ch.8
Being, Computing, Representing


Part 8.6
Continuous Reciprocal Causation



Brief Summary:

Separate parts of a system can be in a state of continuous reciprocal causation, meaning that the behavior of each part simultaneously affects the behavior of the other parts. In such cases, it is not best to explain the whole system’s by analyzing the system into insulated parts. And also, representational accounts might not best explain how one part can be found internally affecting another part.



Summary

[Recall that a position is “representationalist if it depicts whole systems of identifiable inner states (local or distributed) or processes (temporal sequences of such states) as having the function of bearing specific types of information about external or bodily states of affairs”. (147a)] Clark will offer one last way to make a strong anti-representationalist argument. He will appeal to “the presence of continuous, mutually modulatory influences linking brain, body, and world.” (163b) Clark previously described the neuronal processes involved in vision, which had “hints of such mutually modulatory complexity in the interior workings of the brain itself.” (163b) Clark now wonders what if “something like this level of interactive complexity characterized some of the link among neural circuitry, physical bodies, and aspects of the local environment?” (163b)

 

[Consider if a radio and a transmitter were near one another, and the transmitter is broadcasting music from a turntable, also nearby. This means that low frequencies playing on the radio will disrupt the needle on the record, but the disruption of the needle on the record will change what the radio is playing.] Clark gives this example.

Consider a radio receiver, the input signal to which is best treated as a continuous modulator of the radio’s “behavior” (its sound output). Now imagine (here is where I adapt the analogy to press the point) that the radio’s output is also a continuous modulator of the external device (the transmitter) delivering the input signal. In such a case, we observe a truly complex and temporally dense interplay between the two system components – one which could lead to different overall dynamics (e.g. of positive feedback or stable equalibria) depending on the precise details of the interplay. The key fact is that, given the continuous nature of the mutual modulations, a common analytic strategy yields scant rewards. The common strategy is, of course, componential analysis, as described in chapter 6. To be sure, we can and should identify different components here. But the strategy breaks down if we then try to understand the behavior unfolding of one favored component (say, the receiver) by treating it as a unity insulated from its local environment by the traditional boundaries of transduction and action, for such boundaries, in view of the facts of continuous mutual modulation, look arbitrary with respect to this specific behavioral unfolding. They would not be arbitrary if, for example, the receiver unit displayed discrete time-stepped behaviors of signal | receiving and subsequent broadcast. Were that the case, we could reconceptualize the surrounding events as the world’s giving inputs to a device which then gives outputs (“actions”) which affect the world and hence help mold the next input down the line – for example, we could develop an interactive “catch and toss” version of the componential analysis, as predicted in chapter 6. (163-164)

[So if we were to analyze for example the component of the radio as if insulated from its environment, we would not know where to begin, assuming that the process had already begun. But if each causal event happened in temporal steps with gaps between, then we could analyze the components of the causal relation.]


Clark offers a second example (from Randy Beer). [First consider this description of oscillating or reverberating circuits in Marieb and Hoehn’s Human Anatomy & Physiology (quoting):

In reverberating, or oscillating, circuits, the incoming signal travels through a chain of neurons, each of which makes collateral synapses with neurons in a previous part of the pathway.

As a result of the positive feedback, the impulses reverberate (are sent through the circuit again and again), giving a continuous output signal until one neuron in the circuit fails to fire. Reverberating circuits are involved in control of rhythmic activities, such as the sleep-wake cycle, breathing, and certain motor activities (such as arm swinging when walking). Some researchers believe that such circuits underlie short-term memory. Depending on the specific circuit, reverberating circuits may continue to oscillate for seconds, hours, or (in the case of the circuit controlling the rhythm of breathing) a lifetime. (Marieb and Hoehn, 422d)


Andy Clark’s second example involves such oscillating neurons,] he writes:

Consider a simple two-neuron system. Suppose that neither neuron, in isolation, exhibits any tendency toward rhythmic oscillation. Nonetheless, it is sometimes the case that two such neurons, when linked by some process of continuous signaling, will modulate each other's behavior so as to yield oscillatory dynamics. Call neuron 1 "the brain" and neuron 2 "the environment." What concrete value would such a division have for understanding the oscillatory behavior? (164a.b)

[So the neurons mutually modify one another, because they have both inputs from and outputs to one another.]


When we are interested in the behavior of the two insofar as they are mutually affecting one another, it would not make sense to analyze the workings into insulated components, even though indeed the system is made of discrete parts.

in the case of biological brains and local environments it would indeed be perverse—as Butler (to appear) rightly insists—to pretend that we do not confront distinct components. The question, however, must be whether certain target phenomena are best explained by granting a kind of special status to one component (the brain) and treating the other as merely a source of inputs and a space for outputs. In cases where the target behavior involves continuous reciprocal causation between the components, such a strategy seems ill motivated. In such cases, we do not, I concede, confront a single undifferentiated system. But the target phenomenon is an emergent property of the coupling of the two (perfectly real) components, and should not be "assigned" to either alone. (164c.d)


Such continuous reciprocal causation is common in our everyday lives.

Nor, it seems to me, is continuous reciprocal causation a rare or exceptional case in human problem solving. The players in a jazz trio, when improvising, are immersed in just such a web of causal complexity. Each member's playing is continually responsive to the others' and at the same time exerts its own modulatory force. Dancing, playing interactive sports, and even having a group conversation all sometimes exhibit the kind of mutually modulatory dynamics which look to reward a wider perspective than one that focuses on one component and treats all the rest as mere inputs and outputs. Of course, these are all cases in which what counts is something like the social environment. But dense reciprocal interactions can equally well characterize our dealings with complex machinery (such as cars and airplanes) or even the ongoing interplay between musician and instrument. What matters is not whether the other component is itself a cognitive system but the nature of the causal coupling between components. Where that coupling provides for continuous and mutually modularity exchange, it will often be fruitful to consider the emergent dynamics of the overarching system. (165a.b)

[This is like Deleuze’s notion of rhythm in Spinoza’s affection, see the end of section 6 of my paper “Body and World in Merleau-Ponty and Deleuze”:

Our active self-affection and adaptive interaction with the world around us is what Deleuze here calls "rhythm." He also offers the example of swimming through a powerful wave. When we collide with the wave, its affection begins to decompose our body. Yet, by self-affectively altering the arrangements of our own body's parts, we may swim in conjunction with the wave and together form a larger composite body. Deleuze suggests another illustration to explain more clearly how affective rhythm involves couplings of continuous affective variations. He has us consider a dual improvisation of a violin and a piano. On the one hand, each one needs to improvisationally choose its own development. Yet, the musicians' decisions will influence how the other plays in concord with it. So, in order for both instruments to maintain their differential co-composition, they must make self-modifications that are differentially compatible with those of the other player. (Shores 203)

]

 

So when there is continuous reciprocal causation, there is little use for an analysis that looks at the parts of such systems as if they were separate.

Thus, to the extent that brain, body, and world can at times be joint participants in episodes of dense reciprocal causal influence, we will confront behavioral unfoldings that resist explanation in terms of inputs to and outputs from a supposedly insulated individual cognitive engine. (165c)

Clark thinks that there are then only two possibilities for the use of internal representation for cognitive scientific explanations. (165c)


To understand the first possibility, we consider a complex neural network, called ‘A’. It is coupled with its environment, and part of its dynamics is an ability to sense whether it the environmental processes it is coupled to are present. “Imagine a complex neural network, A, whose environmentally coupled dynamics include a specific spiking (firing) frequency which is used by other onboard networks as a source of information concerning the presence or absence of certain external environmental processes—the ones with which A is so closely coupled.” (165d) So internally we might say the system has patterns for when it is coupled to external processes. Now we are to consider those signals normally coming from outside to be produced from the inside, causing the system to ‘imagine’ being engaged with the environment rather than physically being so. This would be like internal representation.

The downstream networks thus use the response profiles of A as a stand-in for these environmental states of affairs. Imagine also that the coupled response profiles of A can sometimes be induced, in the absence of the environmental inputs, by top-down neural influences, and that when this happens the agent finds herself imagining engaging in the complex interaction in question (e.g., playing | in a jazz trio). In such circumstances, it seems natural and informative to treat A as a locus of internal representations, despite its involvement, at times, in episodes of dense reciprocal interaction with external events and processes.” (163-164)


The other possibility is that even such inner processes cannot operate unless they are coupled, and thus there are nonrepresentational dynamics at play.

A second possibility, however, is that the system simply never exhibits the kind of potentially decoupled inner evolution just described. This will be the case if, for example, certain inner resources participate only in densely coupled, continuous reciprocal environmental exchanges, and there seem to be no identifiable inner states or processes whose role in those interactions is to carry specific items of information about the outer events. Instead, the inner and the outer interact in adaptively valuable ways which simply fail to succumb to our attempts to fix determinate information processing roles to specific purely internal, components, states, or processes. In such a case the system displays what might be called nonrepresentational adaptive equilibrium. (A homely example is a tug of war: neither team is usefully thought of as a representation of the force being exerted by the other side, yet until the final collapse the two sets of forces influence and maintain each other in a very finely balanced way.) (166b.c)


Thus,

Where the inner and the outer exhibit this kind of continuous, mutually modulatory, non-decouplable coevolution, the tools of information processing decomposition are, I believe, at their weakest. What matters in such cases are the real, temporally rich properties of the ongoing exchange between organism and environment. (166c)

Such instances do not challenge the representational model, because they do not fall under the class of cases best suited for representational explanations. Clark will explain this in the next section. (166d)

 

 

Clark, Andy. Being There: Putting Brain, Body, and World Together Again. Cambridge, Massachusetts/London: MIT, 1997.

 

Marieb, Elaine N., & Katja Hoehn. Human Anatomy & Physiology. London: Pearson, 2007.

 

Shores, Corry. “Body and World in Merleau-Ponty and Deleuze” in Sudia Phaenomenologica, vol.12, 2012, pp.181-209.

https://cdn.anonfiles.com/1360747598945.pdf



Andy Clark. 7.3 of Being There, “Primate Vision: From Feature Detection to Tuned Filters,” summary


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Andy Clark

Being There:
Putting Brain, Body, and World Together Again

Ch.7
The Neuroscientific Image


Part 7.3
Primate Vision: From Feature Detection to Tuned Filters



Brief Summary:

The neuronal visual systems in the brain have parts that are maximally tuned to process data for one visual parameter or another, meaning that rather than having cells responsible for dealing only with certain complex forms [like a spiral], many various cells in the system cooperatively play a role in understanding all the visual properties of something being seen [like something’s spirality, breadth, etc, perhaps].



Summary

Clark will discuss neuroscientific research into primate vision, especially work by David Van Essen. (133c.d)


Cognitive neuroscience examines neuronal responses.

Anatomically, the macaque monkey possesses at least 32 visual brain areas and over 300 connecting | pathways. Major areas include early cortical processing sites such as V1 and V2, intermediate sites such as V4 and MT, and higher sites such as IT (inferotemporal cortex) and PP (posterior parietal cortex) (plate 1). The connecting pathways tend to go both ways—e.g. from V1 to V2 and back again. In addition, there is some "sideways" connectivity—e.g. between subareas within VI. (133-134, boldface mine)

 

image
(From Clark p.170)

There are ten levels of cortical processing in the system, and we will look at some of the more important ones. There are three populations of sub-cortical cells from which the system receives input. One population is the magnocellular (M) and another is the Parvocellular (P). And there is a processing pathway for M, and another one for P. Each population specializes in a different type of low-level information. P cells “have high spatial and low temporal resolution”, while M cells have “high temporal resolution.” (134b) This means that M cells deal with rapid motion perception, while P cells deal with color discrimination (among other things). So when we selectively destroy a monkey’s P cells, it can no longer distinguish colors although it still recognizes motion. (134b)


So the magno M cells discern motion, and there is a magno-denominated (MD) stream of processing. This stream includes neuron populations that are sensitive to the direction of some motion, especially in area MT, which we said above was an intermediate cortical processing site. When we electrically stimulate a part of MT, the monkey might “perceive” left motion even if the target object is really moving to the right. There is a higher stage in the processing hierarchy, MSDT, where there are cells sensitive to spiral motion.

The MD stream is ultimately connected to the posterior parietal cortex, which appears to use spatial information to control such high level functions as deciding where objects are and planning eye movements. (134d)


There is also the task of object recognition, which is determining what things are. This is handled by a stream rooted in P inputs, moving through V1, V4, and posterior inferotemporal areas (PIT), and it leads into central and anterior inferotemporal areas. (134d) This pathway specializes in form and color. As we go up the hierarchy, we find sites capable of processing increasingly complex forms. At a high level, there are even cells that respond maximally to such complex geometrical visual stimuli as hands and faces. (135a). But although one cell responds maximally to one kind of form, like a spiral, it will also to a lesser extent respond to other sorts of patterns.

image

[This means that cells are not like yes-no sensors that detect the presence of one form or its absence, but rather each participate in contributing information about some property of what is being seen, with all working together cooperatively.]

Although a cell may respond maximally to (e.g.) a spiral pattern, the same cell will respond to some degree to multiple other patterns also. It is often the tuning of a cell to a whole set of stimuli that is most revealing. This overall tuning enables one cell to participate in a large number of distributed patterns of encoding, contributing information both by its being active and by its degree of activity. Such considerations lead Van Essen and others to treat cells not as simple feature detectors signaling the presence or absence of some fixed parameter but rather as filters tuned along several stimulus dimensions, so that differences in firing rate allow one cell to encode multiple types of information. There is also strong evidence that the responses of cells in the middle and upper levels of the processing hierarchy are dependent on attention and other shifting parameters (Motter 1994), and that even cells in VI have their response characteristics modulated by the effects of local context (Knierim and Van Essen 1992). Treating neurons as tunable and modulable filters provides a powerful framework in which to formulate and understand such complex profiles. (135a.b, boldface mine)


But even though visual systems are complex, they can still be analyzed. (135d)


Andy Clark. Being There: Putting Brain, Body, and World Together Again. Cambridge, Massachusetts/London: MIT, 1997.



Andy Clark. 8.2 of Being There, “What is this Thing Called Representation?,” summary


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Andy Clark

Being There:
Putting Brain, Body, and World Together Again

Ch.8
Being, Computing, Representing


Part 8.2
What is this Thing Called Representation?



Brief Summary:

There is a view in cognitive science that believes ‘thinking’ systems such as brains and thinking machines have internal representations that correlate with the external world but are also processed without the direct causal influence of external factors.



Summary

Clark will discuss “internal representations”. Cognitive scientists often refer to them as being housed by brains and computer models. The concept helped bridge connectionism and classical artificial intelligence. Both camps agreed there are such internal representational systems, however they disagreed on the precise nature of them. (142d) The classicists thought mental contents were “tokened as strings of symbols that could be read, copied, and moved by some kind of inner central processing unit” (143a); they believe then in a “chunky symbolic” inner economy of mental contents. Connectionists however “believed in a much more implicit style of internal representation: one that replaced strings of chunky, manipulable symbols with complex numerical vectors and basic operations of pattern recognition and pattern transformation” (144a)


Both views see mental contents as internal representations. Haugeland lists the criteria for an internal representational system. [Quoting Clark:]

(1) It must coordinate its behaviors with environmental features that are not always "reliably present to the system."

(2) It copes with such cases by having something else (in place of a signal directly received from the environment) "stand in" and guide bahavior in its stead.

(3) That "something else" is part of a more general representational scheme that allows the standing in to occur systematically and allows for a variety of related representational states (see Haugeland 1991, p. 62). [144b]

Now consider plants that track the sun with their leaves. The sun’s changing position itself guides the leaves’ motion. So because the plant system is controlled by an environmental feature that is reliably present to the system [perhaps, to the system’s behavior], it would not satisfy the first criterion. [Consider instead a solar panel programmed to turn with the sun’s position. It need not even ‘see’ where the sun is. It can be programmed according to astronomical predictions of its position. These coordinates ‘stand-in’ for the direct control of the sun’s actual position on the plant leaf movement.] Point two says that instead of the environmental feature, something else stands-in for it and guides the system’s behavior. [Now consider how before eating, we see the food, and our stomach produces gastric juices, then in their place comes food. In a way,] our gastric juices stand-in for the food, and in that way represent the future presence of food. However, the third criterion says that the something else that stands-in must be a part of a larger representational system, and the gastric juice does not. [Yet the sun’s coordinates fit within a larger system of geometrical representations.] Clark thinks that the role of the decouplability of the inner and outer states in determining behavior is overplayed. (144c.d)


But consider the way that the neurons in a rat’s brain process coded signals for which way the head is pointed. The system uses a general representational scheme, but Clark wonders if really this part of the system can function even if it were decoupled from “the continuous stream of proprioceptive signals from the rat’s body.” (145)


A strict application of Haugeland’s criteria will not help us understand the flows of information in such neuronal systems that come from the body. (145)


So Haugheland’s criteria is a bit too restrictive; nonetheless we still need a way to constrain the applicability of the concept of internal representation. For, we need to rule out simple cases of environmental control over the system’s behavior. Also, internal complexity in a system is also alone not enough to qualify as inner representation. In addition, a correlation between an inner state and some environmental parameter is insufficient for inner representation [recall the gastric juice example]. “It is thus important that the system uses the correlations in a way that suggests that the system of inner states has the function of carrying specific types of information.”  (146a)


So the fact that the tides correlate with the moon’s position does not mean that either represents the other; for, the correlation was neither designed nor evolved for the purpose of carrying information about the other’s variations. On the other hand, the neuronal activity in the rat’s brain does seem to have the purpose of carrying information about the head’s position. (146b.c)


So what will qualify an inner state as a representation will have to do with the role it plays in the system.

It may be a static structure or a temporally extended process. It may be local or highly distributed. It may be very accurate or woefully inaccurate. What counts is that it is supposed to carry a certain type of information and that its role relative to other inner systems and relative to the production of behavior is precisely to bear such information. (146cd)


So Clark proposes that we

call a processing story representationalist if it depicts whole systems of identifiable inner states (local or distributed) or processes (temporal sequences of such states) as having the function of bearing specific types of information about external or bodily states of affairs. (147a, boldface mine)

Consider such adaptive hook-ups as the sunflower tracking the sun’s position, or a robot seeking light. Clark thinks there is little to gain by calling such adaptive hook-ups representational.

Representation talk gets its foothold, I suggest, when we confront inner states that, in addition, exhibit a systematic kind of coordination with a whole space of environmental contingencies. In such cases it is illuminating to think of the inner states as a kind of code that can express the various possibilities and which is effectively "read" by other inner systems that need to be informed about the features being tracked. Adaptive hookup thus phases gradually into genuine internal representation as the hookup's complexity and systematicity increase. At the far end of this continuum we find Haugeland's creatures that can deploy the inner codes in the total absence of their target environmental features. Such creatures are the most obvious representers of their world, and are the ones able to engage in complex imaginings, off-line reflection, and counterfactual reasoning. Problems that require such capacities for their solution are representation hungry, in that they seem to cry out for the use of inner systemic features as stand-ins for external states of affairs. (147bc)


Those who like dynamic systems theory tend toward rejecting information-processing accounts “that identify specific inner states or processes as playing specific content-bearing roles.” (148b) They thus might endorse this radical thesis:

Thesis of Radical Embodied Cognition  Structured, symbolic, representational, and computational views of cognition are mistaken. Embodied cognition is best studied by means of noncomputational and nonrepresentational ideas and explanatory schemes involving, e.g., the tools of Dynamical Systems theory. (148c)


Many scientists already hold this view. (49a)


But Clark thinks such a strong reaction is unwarranted, and he will explain why in the following sections. (49b)




Andy Clark. Being There: Putting Brain, Body, and World Together Again. Cambridge, Massachusetts/London: MIT, 1997.

20 Feb 2013

Andy Clark. 2.4 of Being There, “Soft Assembly and Decentralized Solutions,” summary


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Andy Clark

Being There:
Putting Brain, Body, and World Together Again
 
Ch.2
The Situated Infant

Part 2.4
Soft Assembly and Decentralized Solutions



Brief Summary:

Machines, including the ‘machinery’ of infant learning, can better adapt to complex and dynamic situations when information processing is decentralized.



Summary

Clark will discuss soft assembly in human development. (42)


Traditional robotic programming is hard assembled, because it does not make real-time adjustments, unlike the soft assembly of human motion.

A traditional robot arm, governed by a classical program, provides an example of "hard assembly." It commands a repertoire of moves, and its success depends on the precise placement, orientation, size, and other characteristics of the components it must manipulate. Human walking, in contrast, is soft-assembled in that it naturally compensates for quite major changes in the problem space. As Thelen and Smith point out, icy side- | walks, blisters, and high-heeled shoes all "recruit" different patterns of gait, muscle control, etc., while maintaining the gross goal of locomotion. Centralized control via detailed inner models or specifications seems, in general, to be inimical to such fluid, contextual adaptation. (42-43) […]

Multi-factor, decentralized approaches, in contrast, often yield such robust, contextual adaptation as a cost-free side effect. This is because such systems, as we saw, create actions from an "equal partners" approach in which the local environment plays a large role in selecting behaviors. In situations where a more classical, inner-model-driven solution would break down as a result of the model's incapacity to reflect some novel environment change, "equal partners" solutions often are able to cope because the environment itself helps to orchestrate the behavior. (43, boldface mine)

[Previously Clark describes childhood development and how many factors in both the child and his environment are equal partners in guiding its development.]


Pattie Maes invented a way for machines to determine among themselves how to distribute jobs, rather than having a centralized system handle all the data and make that decision. Each machine when creating a job asks the other machines to estimate how long they would take to perform it, and the machine most able given its current abilities and activities gets the job. Job scheduling then becomes an “emergent property” of the simple machine self-assessment and communication behaviors. (43d)


Thus

Soft assembly out of multiple, largely independent components yields a characteristic mix of robustness and variability. The solutions that emerge are tailored to the idiosyncrasies of context, yet they satisfy some general goal. This mix, pervasive throughout development, persists in mature problem solving and action. Individual variability should thus not be dismissed as "bad data" or "noise" that somehow obscures essential developmental patterns. Instead, it is, as Thelen and Smith insist, a powerful clue to the nature of underlying processes of soft assembly. (44a)


Thelen and Smith give the example of the development of child reaching behavior, where the factors and events leading up to the learned behavior vary widely between children even though the resulting behavior is similar for all. (44b)


One child began with fast flapping then dampened it. (44bc)


Another had to increase lift. (44c)


Other children exhibited other variations. The central nervous system is merely working with the physics and mechanics of the seemingly somewhat autonomous parts of the body that come to be adjusted. (44-45)


Clark writes:

the job is to learn to modulate parameters (such as stiffness) which will then interact with intrinsic bodily and environmental constraints so as to yield desired outcomes. In sum, the task is to learn how to soft-assemble adaptive behaviors in ways that respond to local context and exploit intrinsic dynamics. Mind, body, and world thus emerge as equal partners in the construction of robust, flexible behaviors. (45a.b boldface mine)




Andy Clark. Being There: Putting Brain, Body, and World Together Again. Cambridge, Massachusetts/London: MIT, 1997.