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THE STRUCTURE AND FUNCTION OF THE PERCEPT
As in many other sciences, especially the ones of the purely mental variety, a good deal in psychology is traditional such for instance are the tripartite and bipartite division of the mind or the various classifications of the mental activities. Of course, classifications as well as theories have their important function in science, but they should not be permitted to become a bed of Procrustes to the guests whom they shelter.
It may sometimes be well to disregard established principles, classifications and time-honored traditions and study the facts from a somewhat different standpoint. We may then possibly see the facts in a new light and realize aspects and connections which are hidden from the customary view of the phenomena. Suppose we take a mental cross-section of a moment of perceptual consciousness in the very act of formation of a percept. The whole perceptual moment may be said to be spread out before our mental gaze. We find sensory elements of a relatively intense character. Certain sensory elements stand out first and foremost in consciousness, they are the very first to arrest the mental gaze and keep it steadily fixed on themselves. In the same view, however, we can also discern other elements, not so prominent, though equally sensory which, on account of their lack of prominence, appear to be of a subordinate character. The whole tone of the percept is given by the qualitative aspect of the prominent elements which seem to guide and form the organization of the percept.
The general plan of the structure of the percept may be compared to that of the cell. A close examination of the cell reveals the presence of a central element, of a 'a nucleus surrounded by cytoplasm with its meshwork, the cyto-reticulum. The nucleus forms the central and important structure having the functions of assimilation and reproduction. The nucleus and cytoplasm, however, are intimately related; the modification of one affects the other. Both nuclear and cytoplasmic structures form one organized whole, one living cell. Similarly in the percept we find a group of sensory elements which constitute the nucleus, and a mass of other sensory elements, possibly the main mass, forming the tissue of the percept. The nuclear elements are more intense and appear to be predominant in the total mental state,―both however are intimately connected and go to form the living tissue of the percept.
The nuclear elements of the percept have the lead and seem to possess the organizing, the fermenting power to assimilate the mass of subordinate elements and have them transformed into one unified organic whole. The slightest modification in the structure and function of the nuclear elements brings about a change in the total cytoplasmic mass of the percept, giving rise to a different structure, to a different percept; and again, modifications of the cytoplasmic mass, so to say, affect the formation of the nuclear elements often resulting in a different percept. It requires however quite a considerable change in the subordinate elements to bring about a change in the percept; while the slightest modification. of the nuclear elements, whether in quality or intensity, often brings about a fundamental transformation of the percept.
The nuclear elements may be regarded as the sensitive, as the vital point of the perceptual system. We cannot displace nor can we modify the nucleus of the percept without profoundly modifying or even completely destroying the life existence of the percept.
We may point out here an important aspect of the percept, an aspect which has been neglected by the older psychologists, but which is now being more and more emphasized by the younger psychologists who lay more stress on the functional and biological side of mental life. Like the life of all organized beings, the life existence of the psychic state is for some reaction, for some adjustments to the conditions of the external environment. In the struggle for existence the animal organism must on pain of death be adjusted to the objects of its external world. Now the central, nuclear, sensory elements awakened by external excitations give the cue for the reaction; they form the sensitive organization for the release of motor energy in definite directions; they signify a definite object to which correspond it , definite motor tendencies with final reactions of adjustment. To the mouse the cat is not an object of contemplation or an object of observation, on account of its sensory effects,―the cat is an object to run away from. To the dog a cat is not an object of beauty, but something to be run after. The sensory stimulations coming from the 'that,' which is mouse, is for the cat something to be on the alert, to jump after and to attack.
The lower we descend in the scale of animal life, the more prominent do the motor reactions become. Where life is predominantly of the instinctive type, the motor side of consciousness is more apparent. The fly attracted by the scent to deposit its eggs in decomposed meat; the wasp that strikes the caterpillar in definite places paralyzing its nervous system, thus preparing food for the coming larva; the newborn infant starting to suck, when put to the breast―are good examples of motor reactions in response to sensory stimulations coming from external objects. A definite sensory stimulus is the trigger which releases a definite set of motor reactions. The fly, the bee is hardly conscious of the sensory characters of the honey; it is more likely that the sensory stimulations of the honey release the appropriate reaction of flying towards it.
The bright colors of flowers developed in the course of natural selection for the fertilization of plants serve the same purpose; they awaken definite responses useful both to plant and insect, as it is hardly probable that the insects are primarily attracted by the beautiful coloring of the flowers. The visual stimuli awakening definite sensory elements may be regarded as central and nuclear which in turn serve as a highly sensitive trigger to release definite systems of motor reactions. The effect is somewhat similar to that of the moth attracted by the flame,―the flame acts as a peripheral stimulus giving rise to sensory elements which form the sensitive trigger in the release of the reaction of circling around the flame, in spite of the harmful results. The moth reacts to bright objects in going towards them, but this particular bright object, the flame, has not been provided for in the motor adjustments of the moth, hence the lack of adaptation, the going to the danger, instead of flying from it.
So apparently insignificant is the sensory side and so predominant is the motor side with its almost mechanically fatal reactions, that some physiologists put the whole mechanism of excitation and reaction in the lower animals under the category of tropisms, which may be positive or negative, according as the animal goes to or from the particular stimulus. The sensory side is denied, the whole affair is regarded as a delicate chemical reaction, such as the chemotaxis of leucocytes in the phenomena of phagocytosis observed in inflammations and bacterial invasions, or what is still simpler as the phenomena of heliotropism observed in the case of plants. This purely mechanical or chemico-physiological view may be crude and far fetched in the case of lower animals, but it brings out strongly the predominance of the motor reaction in response to definite sensory excitations.
The motor attitude of the animal towards the excitations of the external environment constitutes the predominant part of its objective world. The reactions with their sensori-motor effects are part and parcel of the total percept. Sensori-motor life gives reality to the world of objects. The spatial, the resistant, the material character of objects depends on our motor reactions which give content and reality to the world of things. Activity gives the sense of 'physical' reality, the sense of material actuality, or of what is regarded as 'the really real.' In other words, sensori-motor reactions with consequent kinæsthetic sensations may be regarded as constituting the very essence of the real, external, material world,―the world of external, material objects.
The percept as we have pointed out forms one organic whole, the constituent elements are firmly integrated into one living organization. In other words, l just as the organism is not simply an integrated compound of cells, tissues and organs, but all those lower units go to form the higher living unit, the life of the organism as a whole, so we may say that the sensory elements are not the same as the percept, they are anatomically found, on the autopsy of the percept,―the sensory elements are the lower units that help to form the it higher unit, the living percept. From a scientific standpoint, as the result of psychological dissection, the sensory elements going to make up the psychic compound, the percept, may be regarded as different from the total synthesis with its characteristic living activity and its peculiar form of perceptual consciousness. The constituent elements of the percept are not of the same definiteness and intensity. The central nuclear elements stand out more distinct, more definite, and consciousness lights them up with more power and intensity. They are like the mountain peaks―when glade and valley and mountain side are still immersed in darkness, the rising sun greets the mountain tops and plays and caresses them with its rays; when again the shades of evening begin to flit and gather over vale, ravine, and gulch, the rays of the setting sun long linger on the peaks taking of them their last farewell. The central nuclear elements are in the focus of consciousness,―they are the first to be met by the glance of the mental eye and are the very last to be left by it. Consciousness plays with its searchlight on the nuclear sensory elements. The central nuclear elements are intense, distinct, and definite, while the subordinate elements are of far less intensity, are often quite indistinct, are, so to say, on the fringe of consciousness; in fact, may even be entirely subconscious. And still indefinite, indistinct, and submerged as those subordinate elements are, they form the main content of the percept, giving it the fullness of reality.
The nuclear elements form the cue of the total reaction, thus standing for the particular object, forming the reality of the percept for the organism. No wonder then that the cue, though it may be the smallest portion of the percept, none the less forms for the organism the most vital, the most significant as well as the most constant part of the percept. The attitude, the total reaction of the organism depends on the slightest difference in the cue, on the slightest change of the nuclear elements, since the apparently slight modification may often prove of great significance to the life existence of the organism,―it may be a matter of life and death. The nuclear elements constitute the signal, the sensitive trigger for the release of definite reactions towards the changes of external objects. Hence the nuclear elements come to signify, in fact, to constitute the essence of the percept.
A change of the subordinate elements of the percept does not matter so much as the slightest modification in the quality or even in the intensity of the signal. This, of course, does not mean that the subordinate sensory elements are not psychologically and biologically of the utmost consequence to the organism, but they are not of that immediate importance as the focal, nuclear elements appear to the consciousness of the organism. The nuclear elements, as signal, focus the interest of the animal. We can well realize their vital importance, if we consider that the nuclear elements are the flag which indicates friend or enemy, war or peace, life or death if we regard the percept statically, we may describe it figuratively as a psychic compound, the union of the elements having somewhat the character of a chemical combination. A new compound is formed possessing qualities of its own, different from those of the constituent elements. The sensory characteristics are profoundly modified in the synthesis, so much so that they cannot be directly discerned and can only be discovered by patient study. The elements do not exist freely, they are bound up in one indissoluble union of the percept. It seems, as if different qualitative states arise in the union, the qualities of the elements appearing, as if transformed by the effected synthesis.
The percept forms a new compound in which the component elements are disguised and transformed by the qualitative aspect of the central elements. The subordinate elements become adapted to the active nucleus, and come out in the compound with sensory characteristics foreign to their nature. In the process of synthesis the subordinate elements become transmuted and assume the sensory characteristics of the nucleus. To isolate the various elements out of the synthetized percept, the central elements must be shifted,―the subordinate elements must be made focal, giving rise to new percepts, but at the same time making it possible to pass in review the various elements. In other words, the elements become revealed in proportion as we make of them signals, in proportion as they become significant of the total percept with its sensori-motor reactions.
The nuclear elements are the most pronounced, the most prominent, as far as saturation of sensory quality is concerned. They have so much of their peculiar sensory quality that they diffuse it into the other elements,―the subordinate elements appear under the sensory form of the nucleus; they become assimilated by the nucleus, and are saturated with its sensory coloring. This holds true not only in regard to saturation, but also in regard to sensory brightness. The central elements possess a sensory brightness far in excess of other elements, and hence they shed their sensory light on the more obscure, though no less important sensory elements. What however they illumine is not so much the peculiar sensory characteristics of those elements, but their own coloring with which they have saturated the total percept.
The force of the central elements lies specially in the emotional or affective tone with which they are pervaded. They arouse an attitude towards the external world in general and to the special object in particular; Taine would call it a tendency. The individual is stimulated by those nuclear elements; his whole attention is going out in direction to the object that has excited them. The whole organism is invaded by the subtle influence of the nucleus giving rise to definite sensori-motor reactions, intensifying the affective state which permeates the perceptual consciousness.
The affective state of the percept is not always obvious in cases of fleeting percepts, but it becomes manifest, when the central elements become temporarily fixed, the stress and strain of consciousness tending in one direction. The very changes occurring in the flickering intensity of the nuclear elements tend to sharpen the situation, to enliven the interest, strain the attention, and be all agog so to say. The cat getting a glimpse of a mouse, or the dog catching sight of the cat may be taken as good illustrations of the affective states present in perceptual consciousness. The nuclear elements are the ones that are specially charged with affective or emotional states.
Biologically regarded, we can well see the importance of the central nuclear elements, the necessity of their standing out in consciousness as more prominent and more intense than the rest of the sensory elements. Constituting the signal, they come to be the most significant part of the percept, for they announce what 'that' is, they present the object, friend or foe, something to welcome or something to flee from. The central nuclear elements thus come to present objective reality, they safeguard the individual, they are the safety as well as the danger signal. The more delicately differentiated those safety-danger signals are, the more protected the individual is in the struggle for existence. The more sensitive the individual becomes to the least difference of the nuclear elements, the better adjusted will he be to the conditions of the external environment, and the better will be his chances in the process of survival of the fittest.
This brings us to the purposiveness of the percept. One of the important characteristics of the biological process is the final cause, the purpose formed by natural selection out of chance variations, and leading to the preservation of that process, to the preservation of the individual. We should therefore expect that in the psychic process which is the most highly developed biological process, purposiveness, formed out of psychic chance variations, will be one of the most important traits. In the course of phylogenetic and ontogenetic evolution some sensory elements, the ones to which the organism is more sensitive, will be selected and become the indicators of the total percept, they will become the index, or better to say the pain-pleasure flag, the safety-danger signal. The central elements will thus be the most prominent, the most intense for that particular state of perceptual consciousness. The nature and character of the elements will vary with the organization of the species and the individual. The dog will become more sensitive to variations of his olfactory sensations, while man will show marked sensitivity towards delicate differences of his visual sensory elements.
The great sensitivity of the nuclear elements is significant, in so far as they lead to better adaptation and to more successful reactions. It is not of any consequence for the cow to gaze at the stars, for the pig to observe the phases of the moon, but it is a matter of importance for them to perceive any signs of food, or the approach of a beast of prey. The heavenly bodies are non-existent for the brutes, because of lack of all reactions of adaptation, while food and predatory beasts are easily detected, because of the vital reactions bound up in the elements of the percept of which the nuclear elements form the signal. It is on account of the vital reactions that the perceptual nucleus plays such a prominent part and takes the lead of all the other elements.
As I have pointed out in a former work: "The psychic state is for some reaction and that sensory element which gives the cue for the formation of the psychomotor elements, leading to some given reaction is, for the time being, the center, the nucleus of the total state."