27 Feb 2013

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

by Corry Shores
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[Other entries in the Merleau-Ponty phenomenology series.]

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


The Structure of Behavior
La structure du comportement

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.


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)


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
Jacob Cass

Rubin's Vase 2

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