Instinct: A study in social psychology
Chapter 5: The Evolution of Neuro-Psychic Traits —Habits
Luther Lee Bernard
The term neuro-psychic traits is here used to cover all forms of behavior mediated through the nervous system, including the instincts at the lower extreme and the highest type of rational response at the other extreme. This chapter might have been called simply, The Evolution of Behavior, except for the fact that not all behavior is neurally mediated. The term mental traits is also avoided because it implies consciousness and some of the lower types of neuro-psychic adjustments are apparently made without consciousness. The emphasis in this chapter is more especially upon the organization than upon the functioning of the traits, and for this reason the term adjustments is not used in substitution for that of traits. It is the purpose in this chapter to show briefly how the structure and organization of the mind has evolved from the instinctive to the intellectual and rational, with a view to making clear the acquired nature and environmental control of the psychic mechanisms now most used in the processes of adaptation of the organism to its environment.
All intelligent behavior is neurally mediated and it rests ultimately, either phylogenetically or ontogenetically, upon the instincts and the reflexes and tropisms and the random tendencies, if these can be spoken of as separate from the other Simpler forms of neuro-psychic mechanism. The lowest forms of animal life, although not without power of varying their responses to their surroundings, make essentially stereotyped responses to the environment upon which they are
(88) dependent. This is true up through animals of the grade of development of the insects. The vertebrates, however, show a very decided tendency to make variant responses to their environments. And we may say that the more highly differentiated the nervous structure in the vertebrates the more decidedly variant may be the reaction types which they are able to make in case of need. There is another correlation also which should be noted in this connection. Capacity for varying the response appears to be closely related to the fact of prolongation of infancy, which, on the one hand, is correlated with greater variability of neural structure, and on the other hand, with greater immaturity of neural structure during the earlier parts of the post-natal period. Those animal types which have the longest periods of immaturity are the most variable in their neural organization and possess the greatest power to acquire habits.
The fact seems to be that, other things being equal, the higher the type of animal the more complex the environment to which it becomes subject or sensitive. Types of environmental pressures which do not affect the lower life forms, or factors in the environment to which they do not respond, become quite effective with the higher animal organisms and demand responses from them. This greater imminence and development of the environment for higher forms and its more constant and insistent pressure upon them is due primarily to certain changes of which the animal types have become possessed. They have a longer life period, for one thing, and consequently survive through several seasons, while the lower forms, including even the insects, usually survive only through single season. Most of the lower forms live in the water
( 89) which is a relatively uniform environment from the standpoint of chemical content, physical impact, temperature and light conditions. The higher forms of life live on the surface of the earth and are immersed in the earth's atmosphere, which permits of frequent and rapid changes of temperature, pressure and impact, and even of chemical contact. Many of the lower forms, especially of the insects, which live in the atmosphere on the earth's surface take refuge in the ground when it is necessary to render their environment more uniform. Others still undergo metamorphosis upon the approach of a new season, which fact protects them largely from disastrous environmental changes, although the purpose may be primarily something else. Differences in range of habitat and methods of locomotion are other factors which frequently separate the lower from the higher animal forms, especially with reference to their responsiveness to their environments. Most of the land-dwelling vertebrates have the power of traveling long distances and of changing altitudes readily, while practically all of the lower forms, including the winged insects, do not wander far nor ascend high into the earth's atmosphere. The birds especially have a very wide range of habitat and they are also particularly capable of modifying adaptations. They usually possess very large brains in proportion to their total bodily weight. And the most active types of birds are decidedly educable; they are not as stupid as most animals of the same evolutionary stage of development; and they display a constant and lively sense of danger, or are capable of perceiving and avoiding dangers as the result of experience. The power of vocalization and objective symbolization of the birds is greater than that of any other animal below man and this power probably has a close connection with their range of movement and the structural and neural variability attributes correlated with this fact. We might, perhaps, even state as a general principle the hypothe-
(90) -sis that there is a close functional relationship between motility and intelligence; that, other things being equal, the larger the range of movement of a type the greater will be its powers of intelligent, and non-intelligent or unconscious and unreflective adaptation to its environment. Necessarily this must be the case if the type is to survive the multitude of pressures of the environment with which such motility necessarily brings it in contact. Movement horizontally on the earth is perhaps more effective than movement perpendicularly in the air in increasing the power of variable adjustments, because of the greater variety of contacts and experiences which are available from the first type of movement.
Man offers another interesting instance of the influence of motility upon adaptability. While he does not possess the power to fly, except by means of mechanical devices, his power of manipulating his environment is much greater than that possessed by birds. He can bring himself into some spatial relationships with the earth and its inhabitants which are not possible to the winged species. But it is chiefly his power of manipulating his environment by means of the highly differentiated hand, which is controlled by a highly organized brain, that gives him his transcendent advantage over the rest of the animal world in motility and motor adjustment. What he lacks in rapidity of change of place he finds more than compensated by the fundamental and thorough way in which he makes his motor adjustments to his environment. His upright position figures as a minor factor in enabling man to make completer adjustments than the lower animals. Of transcendent importance in this connection, of course, is his power of communicating his ideas and impulses to others by means of speech and language. This affords him a social cooperative agency by means of which he is able, especially with the aid of written or printed language, to transmit his activity impulses to the farthest reaches of the earth. These transcendent traits or
( 91) capacities in man—brain organization, speech, hand—have combined to make him an inventive animal and have brought him directly under the influence of a type of environment which is infinitely more complex than any other kind or organization of environment which operates upon the animal kingdom. This is the psycho-social environment.
First, then, man is an animal possessed of acquired technique. Other animals possess some technique in constructing and in modifying their environments of either an inherited or an acquired nature. But, even in the birds, this lower animal technique is not to be compared with that of man. Man is able in large measure to make his world over on the physical side. He builds aëroplanes with which to emulate the birds; he constructs railways and steamships which carry him quickly to all parts of the earth; he pierces mountains and takes from the bowels of the earth coal and iron and other materials from which he constructs machines by means of which he makes the most minute and the grandest adjustments to nature or subdues her. With the same equipment, internal and external, native and acquired, he constructs the printing press, the telephone and the telegraph, and communicates his ideas or will to all sections of the earth and makes them the common property of all mankind. By means of the telescope he penetrates the secrets of the heavens and with the aid of the microscope he discovers the infinite in the finite and solves many of the problems of the meaning and control of life. With his chemical technique he transforms the functional nature of matter and adapts it better to his uses. Everywhere man's inventive powers and his technology serve him as extensions of his natural organs, so that his legs become longer, his pace infinitely more rapid, his hearing more acute, his powers of vision are
( 92) multiplied in range and effectiveness, and he grows in powers like a god and as if by magic. This power of acquired technique brings him into a vastly more extended and more complex world or environment and by virtue of the increased use of it the necessity arises for an even greater development of his technic powers of adjustment.
But above all, man lives directly under the influence of a type of environment which can operate upon the lower animals only indirectly. For the very lowest forms of life the operation of the psycho-social environment is exceedingly indirect. Only man possesses the powers of symbolization and of apprehension of abstract ideas which render him susceptible to the multiplicity of influences and factors which fall within the psychosocial environment. This is the most complex and insistent of all the environments, and it grows in complexity as man's intelligence grows and as his powers of adjusting to it increase. Only he is cognizant of tradition and custom, of convention and suggestion. Only he builds institutions and inherits them from the past. Only he multiplies knowledge and is dominated through his understanding by its abstract principles. But he is not the only animal who is subject to the power of the psycho-social environment. Every animal, domestic or wild, over which man exercises control, is affected by man's social organization and by his knowledge of fact and his valuations of relationships and conduct. But this is an indirect rather than a direct control, and it is operative only in so far as man is in functional contact with these lower forms.
This brief sketch of the expanding range of movement and of the adjustment capacities of the types of organisms, together with the expanding environment to which they are subjected in the evolutionary process, is intended as an introduction to a statement of the stages of neuro-psychic development through which animal organisms pass. The lowest
( 93) neuro-psychic stage is that of instinct. The lower forms of animal life are controlled almost entirely by instinctive and reflex action mechanisms, although some degree of variability or modifiability in adjustment in response to environmental changes is to be found even among the protozoans. Also among the insects, which are much higher in the scale of development, the adjustment of the organism to the environment is overwhelmingly on the basis of instinct.
But the animal organism becomes more complex and less mechanized in structure, and the life period lengthens and the motility increases as the process of evolution advances. At the same time the environment which operates upon the more complex organisms becomes more and more complex and detailed in its application and changes rapidly in its form. It consequently becomes necessary for the organism to change from time to time in large degree and rapidly the method and content of its adaptation. The growth of the environment,
( 94) both in complexity and in concrete detail, is closely parallel to the ascent of the organism in the scale of development. The two types of development apparently interact upon each other. The differentiation of the environment calls forth a differentiated development in capacity to respond on the part of the organism. Likewise the developing organism, especially in the human type, reacts upon its environment and creates a greater complexity and capacity in the environment to stimulate response on the part of the organism. This creative function of the organism, with respect to the environment, is seen at its maximum in the making of the psycho-social environment, which is man's greatest achievement.
In some cases it is necessary to make rapid changes in temperature adaptation. To a certain extent nature takes care of this, by providing coats of fur or feathers which may be manipulated automatically by the neuro-muscular system and glands in such ways as to increase or diminish the body's retention of heat. In other cases perspiratory glands, also automatically and instinctively operated by an internal mechanism, keep the body at a fairly even temperature on the surface. In man his forethought supplements these instinctive controls with the aid of fire, shelter and clothing and other temperature controls aimed at cooling the body. Intelligence comes in here to cooperate with or to displace instinct. In this case the adjustment is made for the most part (and, as far as this illustration is concerned, wholly) by means of instinct by the lower types; but only partly so by man. Yet, even the lower animals may learn to seek the shelter of a windbreak or the protection of a cave or come close to a fire for the purpose of warming themselves. In such cases they act in part front instinct—the reflex response to pleasureable warmth—and partly from the lessons of past experience which have taught them that comfort, or at least the absence of pain, lay in that direction. This
( 95) illustration is, however, rather complicated. Let us take a simpler one.
Suppose a land animal loses a leg. It is equipped instinctively for walking on four legs, provided it is not an insect, a bird, a kangaroo, or a man. Yet in the course of a short time any animal which can support itself on three legs will adapt itself to the process of locomotion on three legs, in the absence of a fourth. This is clearly a case of habit adjustment modifying an instinctive one. Or, again, animals which lose their sight learn in due course of time to reorganize their instinctive and acquired technique by employing the other senses as adjustment aids in such ways that they can regain much of their former efficiency in the life struggle. In some cases, however, the loss of a sensory adjustment mechanism may be such a serious matter, especially where there is little margin for variation in adaptation between the adjustment organization within the animal and the environment controlled by this organization, that the animal is not able either to survive the period of readjustment of its control organization or is not able to bridge the hiatus with its insufficient sensory or muscular technique, and it perishes. On the other hand, in some of these cases, as in that of the adjustment of the organism to the environment on the basis of the sense of sight, the full efficiency of the adjustment is not attained except through a partial process of learning. This is certainly true in the case of man, who does not at first see either colors, or depth, or measure size or solidity by the eye. Whether the lower animal acquires the power of seeing depth and color we can only conjecture, but there seems to be good reason to thinly that it is not wholly different in this respect from man.
In these cases the modification of the original instincts through habit formations apparently takes place without any self-consciousness or conscious memory of the process which would render it representative. The former case, that of learning to keep warm by establishing the habit of seeking shelter or approaching a fire, obviously must involve the action of some sort of reinstatement mechanism or conditional association, even in animals decidedly lower in the scale of evolution than man. It is easy enough to imagine lower animals using a substitute sense or an acquired walking mechanism without the aid of memory and representative consciousness, but it is difficult to conceive of them automatically seeking shelter from the cold in a cave or in the environs of a fire without some sort of conditioned association to control the act. The one is an immediate physiological habit adjustment set up within the animal's organism itself and is not dependent upon exteroceptive sensory adjustment. The other is an adjustment made largely at a distance through the exteroceptive senses, as well as through those senses more closely connected with the autonomic nervous organization. Such an adjustment is more likely to involve consciousness of a representative sort. The lowest organisms do not make such complex adjustments—those through the higher exteroceptive senses of sight and hearing—at all, because they do not posses exteroceptive senses sufficiently well developed to take care of the details, or a brain organization which can utilize perceptions for purposes of control. It is mainly through these two higher exteroceptive senses, sight and hearing, that the sensory materials for consciousness and memory come.
The distinction between the two types of cases—the modified adjustment made mainly or wholly on the basis of organic internal processes and the adjustment mediated primarily through the exteroceptive senses on the basis of conditioned associations and reinstatement mechanisms—can be made
(97) more striking and may be further extended to higher levels of adjustment, including consciousness, by taking a more pronounced instance of the second type. Such might be the case of a man learning to avoid some danger, as for example a savage avoiding a cave frequented by a bear or other ferocious animal. The act of avoidance, in the case of the human being, involves the perception of danger, of possible injury, by means of the exteroceptive senses and (in the case of man) memory. It also involves the perception of place and of avenues of escape, and the like. Once these connections have been made through the aid of the exteroceptive senses of sight, hearing, and smell, the man need only see the place where the danger is to be incurred, or something which is associated with this place, or hear some sound or smell some object similarly connected with it, to take alarm and hastily beat a retreat. Did this act of retreat upon the perception of a cue to the danger or the dangerous place take place with or without memory of the previous dangerous experience? Does the mind of the man call up imagery tending to restore neuro-psychically this dangerous previous experience and then, following this restoration of the event—in memory—perform the acts of escape as on the previous occasion, except for any variations made necessary by changes in the environment? Or does the man act automatically without defined consciousness and without memory recall upon the perception of the cue to the dangerous situation, merely by means of the neuro-muscular reinstatement of his motor impulses on the basis of the conditioned associations which have been formed? Either supposition is tenable, but ordinarily we assume the operation of the latter processes for animals below man and the former for man himself, as the explanations of the adjustment processes which appear to be the more plausible in the light of the facts as we know them. The lower the animal type the slighter and less well-defined the conscious content connected with such an act
(98) of avoidance; but also we may say, the lower the animal type the less well defined and efficient the act of avoidance following the perception of the cue to the danger, unless it has an instinctive or a conditional mechanism for avoidance which is set off automatically upon the sensory appearance of the cue. There is, apparently, a correlation between the degree of conscious control and the efficiency of the act in such cases, at least before the act is reduced from a conscious performance to the status of an automatic or habitual act.
If the argument is well founded, and if the illustrations are well chosen, we may be justified in speaking of three types of habits—(1) those that are primarily organic and overt, not involving awareness and memory, (a) those that involve the overt organic adjustment with a developing neuro-psychic mechanism depending on conditioned associations and reinstatement mechanisms, that is, those that are both overt and internal in their mediation, and (3) those which are internal and conscious primarily (although there need not be self-consciousness in such cases) and which have but a small overt activity content or correlation. This last type of habit organization is of the nature of a habit of thought—either conscious or unconscious—with primarily a neural instead of a muscular or a neuro-muscular organization. Its method of formation and its significance for the later stages of human social development will be discussed subsequently.
The first of these three types of habits appears in the lower types of habit-forming animals. In fact it may be said to be characteristic in some degree of the lowest or almost the lowest forms of animal life, according to the findings of Jennings and others. However, it does not become pronounced as a method of adaptation until the process of animal evolution reaches the stage of the vertebrates. The other two types come into play higher up in the scale of evolution, the third type scarcely manifesting itself before the advent of
( 99) man, who is the thinking animal par excellence. One error of interpretation must be avoided in this connection, and that is the tendency to think of these three stages of habit formation as definitely distinct. Each subsequent stage or type begins long before the preceding one has reached its maximum development, and each previous type persists long after the next succeeding one has come fully into play. This overlapping and the relative importance of these types at any one time may be graphically illustrated by means of the following diagram..
This diagram is intended to represent only the relative, not the absolute, importance of the different types of habit organization.
Overt habit adjustment is dominant among lower animal forms, in so far as habit adjustment is operative at all. Among the lowest living forms it occurs without dependence on a nervous system, but as a nervous system evolves overt adjustment mechanisms make increasing use of it, until finally some signs of psychic processes begin to appear and these in turn come to play a cumulative rôle, advancing in the final stages of their development t0 dominance of the adjustment processes. The mixed type of habit adjustment is merely a transition process and exists only as a composite fact, and not as a distinct competing principle. Gradually the dominantly conscious (and
(100) subconscious) or internal habit adjustment comes to be dominant over the other types. In this last stage, which is essentially human, adjustments are made in the neural processes before they are made overtly or by the muscular and osseous system. If we diagram the process of the growth of types of habit adjustment on the basis of the competing principles of overt and internal or neuro-psychic technique, and leave out the mixed or overlapping habit-forming process, we have the following figure, which is perhaps truer to neurological and physiological fact than the preceding one.
On the basis of the previous discussion we may now undertake to diagram the different stages of the development of neuro-psychic technique in making adjustments between the organism and its environment. Here again we must warn the reader against interpreting the diagram to mean that the different stages are sharply separated, one from another. To some extent this overlapping can be made clear in the content of the diagram itself. A neuro-psychic trait or process, once it appears, remains as a part of the adjustment mechanism of the organism, although its relative, or even absolute importance, may ultimately decline. Possibly both phases of the importance of both instinct and overt habit have declined in the biological history of the human species. Also, the diagram illustrates the fact that the higher or more abstract and intellectual types of neuro-psychic technique are superimposed upon the lower ones. They do not come directly in contact with the lowest types, such as instinct and overt habit, except
(101) in an ever-diminishing number of cases, because each succeeding superposition modifies the operation of the underlying process or technique. Consequently, the lower processes with which the higher processes ordinarily come in contact and to which they adjust are modified processes. This is really the
explanation of the statement often made by the psychologists, and emphasized in the quotation from Professor Warren in the preceding chapter, that adult individuals have few unmodified instincts. Man literally rises by means of a stairway of habits from adjustment on an instinctive basis to adjustment on a rational basis, passing through, on the way, various stages of conditioned adaptations.
The overt habit, as described above, comes into the adjustment process where the instinct mechanism becomes inadequate to the adjustment needs of the organism, because of the
(102) greater complexity of the environment perceived or reacted to by the more specialized animal type. The overt habit is not necessarily without any definite neural correlate, for ordinarily overt or external action cannot occur except in correlation with neural stimulus-response pathways. Also all habits, overt or internal (neural), are built upon instincts, which are neuro-psychic processes. However, the overt action response may be without conscious neural correlation, since the inner or neural adjustments may take place at sub-cortical levels. Since the lower animal forms are not equipped for conscious direction of the adjustments of the organism to its environment there is either no opportunity or no necessity for bringing the inner adjustment process into the higher brain centers, which are probably inadequately developed for handling such matters. Consequently, so far as conscious control or organization is concerned, the new adjustment on a habit plane is characterized primarily by overt or muscular mechanisms, with a basis of unconscious or unintelligent instinctive neural mechanism.
The overt habit mechanism merges gradually and insensibly into the mixed type, where both the overt action adaptation and the conscious neural organization take place at the same time. In general it may be said that as the conscious adjustment grows the overt process of adaptation tends to be shortened, more and more of the adaptation taking place in the neural centers without being transferred to the muscular and glandular systems for execution in details. That is, the overt action adjustment is increasingly limited to the approximate and ultimate end processes, the intermediate processes being worked out in the nervous system, under either conscious or sub-conscious control. In the third stage of habit formation, where internal or neural habits predominate, this elimination of the bulk of the overt adjustments, leaving only the end
( 103) results of the adaptation to be executed by muscles and glands, reaches a high degree of completeness. Here we have habits of thought or of thinking largely taking the place of the bodily or overt organic habits. When this last stage is reached the individual has already begun to make his adjustments on the basis of abstract or symbolic thinking. The symbols represent activity values, in more or less disguised form, which themselves never or rarely go into overt execution. In the case of the most abstract symbolization, especially that of a quantitative or mathematical sort, the similarity of the abstract symbols to action patterns or mechanisms is not at all recognizable. In such cases the symbols merely represent potential action or action values.
The uncorrupted instinct gives place in this manner to the modification which we call overt acquired action or habit, because the animal cannot meet the demands of his environment on the basis of his instinctive mechanisms. Environment changes and the unmodified operation of instinct would maladjust or misadapt him rather than give him a functional alignment with his surroundings. Flexibility has to come into the neuro-muscular mechanism to save the animal and its type. Evolution itself, at least in the second dimension which we may call progress, cannot go on without this expanded capacity for adaptation. A type of animal life controlled wholly in its adjustments to environment by instinctive mechanisms could survive only if it existed in a relatively static world; it would perish in a rapidly changing environment.
In like manner the growing complexity of the environment and the evolving and differentiating nature of the type in the course of time render adjustment on the basis of the overt habit mechanism. inadequate to its needs. The difficulty here is not alone in the fixity of the mechanism which undertakes the adjustment of the organism to the environment, but also in the time which is required to effect the adjustment. In the case of the purely overt habit mechanism, every process of the adjustment must take place through the muscles. No detail or incidental process can be omitted unless the continuity of the action itself is to lapse. Muscular and bodily movements are extremely time-consuming. They are also fatiguing and thus limit the powers of the organism to consummate its adjustments on the overt basis. We observe these two limitations of time and fatigue at work in the attempts of a lower animal to escape from a trap or a maze. It runs to and fro ceaselessly, attempting with its whole body to find a new adjustment which will set it free from its physical restraints. The human being might react in much the same way at first, if placed under similar circumstances or environmental conditions, especially if under the influence of emotional excitement, but it would tend—if normally intelligent or capable of internal habit adjustment—to work out the problem of escape in the mind, thus saving the time and energy involved in the so-called "aimless" movements of the whole organism for application to the end process of escaping after the preliminary processes had taken place internally or neurally. The animal types using the overt habit adjustment exclusively or
(105) primarily would not be able to accomplish any marked achievement in the control of their environment merely for lack of time and energy saving, even if their lack of inventive capacity were not a fatal handicap. Invention is primarily a matter of internal habit adjustment or abstraction, made overt finally in the application of the results of the internal, adjustment processes to the end processes of adjustment.
The internal type of adjustment is a great time saver. It dispenses with the overt adjustment except where it is necessary to carry the results of the internal adjustment—which are, in their higher forms, rational conclusions—into operation, or so to manipulate the environment as to give a basis for further internal adjustment. Of course the internal adjustment process is never ideal or perfect, just as the overt process is never perfect or wholly effective. There are necessarily many hitches in the process of thinking an adjustment situation through, even where the most abstract processes of thinking and symbolization have been developed as aids in the internal processes. Also, it is not always easy for the internal processes to inhibit the overt processes from action, with the consequent interference with the internal or thought adjustment which such overt action brings. Usually, however, the inadequacy of the internal adjustment process results from what we call lack of data. Either adequate symbols of the environmental pressures are lacking or the end results cannot be properly foreseen. Facts or data depend upon the power of the internal—usually conscious or thought—mechanism to visualize or apprehend the relationships of the environment to the organism. Data are such symbolizations of the environmental relationships. Where this symbolization does not exist in adequate degree or extent and the internal
( 106) adjustment process cannot go on through a process of abstraction and valuation, the overt action must intrude and carry on the adjustment externally, although in a more or less random and uneconomic manner, until the internal processes can pick up the thread of abstraction and symbolization and help the process on a more economical plane.
The mixed type of adjustment occurs in just such situations where there is inadequate power or experience for abstract and symbolical adjustment. It ordinarily occurs in those forms of animal life where the cortical conscious mechanisms are just coming into functional operation, but it may and does occur among thinking men—even among philosophers—when they find themselves in strange or incompletely understood situations. At such times the adjustments cease to be abstract and rational and are interrupted by more or less random movements which often give the appearance of high emotional excitement in the subject. The process of "getting hold" of a situation is to bring the uncompleted adjustment process back to the inner basis and think out the plan of action before there is any attempt to execute it. When this is done, not only is time saved, but also there is less waste movement and loss of energy. Also, which is an important consideration, there is a much greater degree of accuracy in the adjustment. The accuracy of the internal adjustment depends on the accuracy of symbolization of the relationship between the environment and the organism, that is, the accuracy of the data available. Where this accuracy is complete and dependable, and where the process of internal adjustment is not interrupted by uncontrolled overt habit action, a rational plan of conduct and control of a high order can be worked out and put into execution.