Social Psychology: An Analysis of Social Behavior
Chapter 3: The Biological Bases of Individual Behavior
No matter just how our species came to be, the essential features and functions of our life are rooted in our animal ancestry. In this chapter we shall first discuss the problem of heredity and environment, then review the basic data relating to the organic foundations of behavior, especially the neuro-muscular-glandular system, and finally indicate the relation of personal-social and cultural stimuli to the physical functioning of the organism.
A. Heredity and Environment not Antagonistic but Correlative.
There has been much discussion concerning the relative weight of heredity and environment in the determination of man's behavior. These discussions seem to the writer useless, because they fail to note that the two influences are not mutually exclusive and opposite but correlative to one another. Most of the old controversy of heredity versus environment is thus rather pointless. Hereditary factors operating through the germ plasm seem to determine the general forms or patterns of physical development. Just how these shall develop seems largely determined by the environmental pressures. The significant work of Child makes this clear. He pointedly indicates that what the individual becomes depends upon the chemical forces operating inside the organism in terms of certain environmental pressures outside:
The conception of the organism as a behavior pattern appears in its clearest aspect in the development of the individual organism. Each organism begins its life as a distinct individual entity, in the form of a fertilized egg, or spore, or something similar. From these, there develops, by an orderly definite process, an individual of the particular species, with its characteristic structure and functions. In the past this development was regarded as a process predetermined by something intrinsic in the protoplasm; its other words, by heredity. The underlying idea was that the organism was a mechanical system, like a machine, for
(36) a machine in the hands of its maker is completely constructed before it starts to operate and perform the definite functions for which it was made.
The modern theories of heredity, as a result of the more recent experimental work on the lower organisms, incline to the belief that the cell, so far as heredity is concerned, does not become fundamentally altered—at least not in the earlier stages of its development. Every cell inherits the whole germ plasm; all cells are primarily alike, up to a late stage in their development. Present-day theories of heredity do not include an explanation of development. Therefore development appears all the more clearly as a real problem open to observation and experimentation.
It has been found that development can be controlled and that it can be profoundly altered by external factors. We can even make out of eggs organisms which could never be recognized as belonging to the same species as the parent form. Yet the eggs of these individuals will produce, ordinarily, perfectly normal individuals in the next generation. Instead of the outcome being a matter of inherent traits of the germ plasm, it is open to a wide range of modification and to prediction through experimental methods.
The organism is not the same as the substance called protoplasm. The protoplasm itself is made up of a great variety of chemicals, in various proportions, such as water, salt, etc. Protoplasm may be defined as a chemical system made up of a multitude of molecules and atoms. It is, of course, also a colloidal organization constituted by multiplex colloids; but the organism is something more than this—it is a system on a still larger scale than protoplasm. The organism is a relation between protoplasmic systems; it is an integration, on a grander scale, of protoplasmic systems.
But how is this integration of protoplasmic systems possible? Are there intrinsic factors in the protoplasm, or factors extrinsic to it that produce this result? Does protoplasm integrate itself, or is it integrated by outside influences? How does an orderly, related organization arise from a mass of protoplasm? This is a basic problem in the notion of an organism.
A new conception in biology is that of the organism as a whole. Different biologists have read different meanings into this idea. There is a somewhat mystical interpretation that the organism is something more than the sum of its parts. Then there is another explanation of the organism as the relation existing between its component parts. As a matter of fact, the wholeness and unitary character of the organism does not arise simply from the facts that it has parts, but from the fact that these parts are physiologically related to one another. This influence between parts is called physiological correlation. By physiological correlation is meant all the possible influences that one part, or different parts, can have on other parts. In general, these correlative effects fall into two groups: first, the chemical or transportative relations; and second the dynamic or transmissive relations.
1. There are first the chemical factors which are present in the higher organisms. These may be spoken of as chemical correlations. These chemical
(37) factors, such as hormones and internal secretions, are produced in one part of the body and transported in mass from that part to another part, or parts, and produce effects on other parts. These relations, of course, are tremendously complex. Illustrations of these chemical factors are the substances produced by the thyroids, adrenals, and gonads. As a consequence of such effects, every, organism has a specific metabolism. Indeed, this type of relationship, where substances produced in one part are transported to other parts, resembles commercial activities in the field of human social life. However, while transportive relations exert correlative effects in the higher organisms, it does not appear to be the primitive type of integrative influence.
2. The dynamic transmissive relation involves something different from transportation in mass; it involves transmission of energy. A multiplicity of mechanical relations can be discerned in every movement of the muscles, as, for example, the flow of blood, chemical energies, thermal energy, electric energy. Through the pressures and tensions there is produced a transmission of a chemical reaction occurring at one place to other places in the organism. We cannot move a muscle without starting minute currents in the body but the most important factor is not any one of these, but a combination of several of them. It is the process of excitation.
All living protoplasms, as far as we know, are capable of becoming excited. No protoplasm can excite itself, nor can it be excited independent of conditions outside itself. Excitation in its most general form is an acceleration in the rate of living, or the physiological changes associated with the processes of living. It speeds up the chemical processes of living, particularly the catabolic side, with the consequent liberation of energy. Now, this process of excitation occurs first, of course, at any point of the protoplasmic exterior, but remains localized only a short time, and is soon transmitted over the whole body. Excitation may be defined as a complex electro-chemical process, in which excitation produces electrical changes resulting in currents which are transmitted, which in turn are transmitted to other points. The nervous system is primarily the organ for the transmission of excitation. The excitation of primitive structures loses its intensity in the process of transmission. The result is that in plants and lower animals gradients in the transmission of excitation may be determined.
In the nerves of higher forms there is little or no loss in the intensity of transmission. Through the nerves excitation is transmitted to an indefinite distance. The nervous system is like a powder trail, where a spark igniting one point spreads, without loss of intensity, through the entire length of the trail. An important fact, however, is that although all the points in the organism may have been alike before the excitation, differences arise after excitation. Any point of excitation secures control or dominance, for the time being. This is a very simple form of integration; indeed it is the most primitive form of integration possible. After excitation, however, the organism seems to show no perceptible change from its condition before excitation. In other `nerds the effects of temporary excitation, for a short period of time, seem to be transient.
When we investigate the earlier stages of development, three main or general patterns, not merely structural but physiological, can be distinguished. The simplest is the exterior pattern. The organism, in this case, is nothing, so far as we can see, but a mass of protoplasm with an outside layer differing from the rest—maybe only in the fact that it is a little denser. Those who have seen the amoeba know how the ectoplasm is differentiated. These differences are not directly due to heredity, but to the relation of the protoplasm to the external world about it. We can cut off a piece of the surface and expose the interior. When the amoeba takes food into its body, it does so by surrounding it. That is, the ectoplasm flows around the food, so that a part of the outside layer becomes a part of the interior. Under these circumstances it loses its characteristics as outside layer. This differentiation is one which is determined directly by the outside world. In such cases heredity represents merely the possibility of that particular protoplasm to produce an internal and external structure as determined by exposure to the world about it.
Most organisms are not so simple as this; most of them have differences between the interior and the exterior, and also display polarity and symmetry.
What are polarity and symmetry? This has been a problem of biologists for a long time. The earliest indications of their existence in organisms are in a form of crude differences in the activity of the protoplasm. Consider any organism possessing a head, for example. The head always arises from the region of the egg which is most active, and the other organs arise symmetrically along an axis of the body.
In many of the simplest forms we have a long, slender body, with attachments in the mud, and the mouth at the tip. If we cut it into little pieces, each is capable of producing a new animal. Normally the structure will arise at the upper end of the piece. The end which is down will become the basal end. The difference in this case is the oxygen supply. The part at the top gets more oxygen; consequently it becomes more active, and therefore produces a new axis.
What I want to point out about these structural features is that so far as we can see, they are not different in any way from those excitation transmission gradients already mentioned. These gradients result from internal activity which persists for a considerable length of time. In certain types of cases, a gradient so produced becomes a permanent difference in the protoplasm. This is a matter not of the inherited capacity of the protoplasm alone, but of the reaction of the protoplasm to external stimuli also. Heredity determines whether we are going to get a fish, a worm, or a man out of that kind of egg. But in all cases this quantitative gradation and the activities based upon it appear to be the starting point of what we may call the development of the individual.
When these gradations become permanent we have a fixed region of control or dominance in the individual. We find that all relations between parts resolve themselves into quantitative relations depending merely upon such dominance and subordination. Thus it becomes quite clear that the order and unity
(39) of the organism are really products of the reaction of the protoplasm. In the broad sense, they are the products of behavior. The protoplasm, from the first moment of its existence, is behaving with reference to its environment.
In this general biological sense, life is reaction to environment.
The following quotation from Hoyt describes the type of experiment which shows the nice balance of hereditary tendency and environmental influences.
Stockard, exposing the eggs of a marine fish, Fundulus, to sea water with the addition of certain magnesium salts and of some other substances, obtained developing young showing marked difference from the characteristics usually shown, notably the development of one-eyed fish. Sometimes this single eye was on one side of the head, giving a cyclopean form. It seems that, in these fish the two eyes will develop in their usual places if the eggs are exposed to untreated sea water, but that various modifications of eye development and location appear if the sea water contains an unusual amount of certain magnesium salts. If, now, the sea water regularly contained larger amounts of these magnesium salts, should we not have these unusual forms of the eye as the usual characteristics of the species? In that case, by removing some of the magnesium salts we should obtain "abnormal" forms bearing two eyes, one on each side of the head. We can not too strongly emphasize the fact that many of the so-called abnormalities are normal developments under particular conditions.
While the hereditary factors may determine the possession of eyes, the place and number of eyes in 'the fish in question seems a result of changes in the chemical nature of the environment. Thus, although the transmission of adult characteristics and organs depends upon the hereditary carriers called the genes, these units of heredity do not develop in vacuo, nor are they some minute mysterious traits or organs which merely unfold in the course of bodily growth. As Jennings puts it:
The genes, then, are simply chemicals that enter into a great number of complex reactions, the final upshot of which is to produce the completed body. The characters of the adult are no more present in the germ cells than is an automobile in the metallic ores out of which it is ultimately manufactured. To get the complete, normally acting organism, the proper materials are essential; but equally essential is it that they should interact properly with one another
(40) and with other things. And the way they interact and what they produce depends on the conditions . . . .
Clearly, it is not necessary to have a characteristic merely because one inherits it. Or more properly, characteristics are not inherited at all; what one inherits is certain material that under certain conditions will produce a particular characteristic; if these conditions are not supplied, some other characteristic is produced . 
In our psychological analysis of social behavior we shall see again and again that no one-dimensional, particularistic explanation is sufficient.  In tracing the development of the biological organism into a more or less socialized personality, we must at all times take into account both hereditary and environmental factors; and the latter, as we noted, must include not only other persons or social experience, but those precipitates of social living—together in the past which we denote as culture. Much of the argument over intelligence measurement, over racial differences, over the effectiveness of education in changing human nature, would disappear if the participants in the debate were only more conscious of the twofold rather than the one-sided nature of the factors which produce variations. Apparently hereditary influences put definite limits upon the intellectual development and the habit-forming capacity of most of us, but what we do in our world of social participation depends also upon environmental conditioning.
B. Fundamental Structures and Functions.
Like all other animals, man is made up of a certain organization of protoplasm living in an environment. The essential attributes of proto-plasm with which we are concerned are first, irritability or capacity to receive stimuli from the environment; second, ability to respond to them; and third, plasticity or modifiability of this protoplasmic organization. This capacity for modification of tissue makes possible alterations in subsequent contacts with the environment. Life consists, at the physiochemical level, of a continuous series of energy changes through which adaptation to the world around us takes place. For us, then, the capacities of irritability and modifiability are the particularly significant aspects
(41) of these energy changes, which take place through the various organic structures. In order to form a picture of the organism in its adjustment to the environment, we may note the principal structures and their functions which have to do with social adjustment.
The adaptation of the organism to its surroundings involves the total-going complex of organs and functions. The basic physiological systems are those of digestion, respiration, circulation, reproduction, and elimination. Food is changed into chemical energy; the blood is aerated through oxygen; carbon dioxide and other waste products are thrown off from the organism. These systems are concerned with the maintenance of life and its propagation in a new generation. In order to facilitate these biological purposes, however, the neuro-muscular-glandular systems have developed. The coördination of all these functions into an integrated whole takes place through the autonomic and central nervous systems. For our purposes these systems are most significant. Still, it must be recognized at all times that they function largely to facilitate the continuance of these other life-supporting organs. All of the systems together constitute the integrated organism; and this integration is made possible through the neuro-muscular-glandular system. The adjustment to environment with which we are concerned, therefore, takes place through the mediation of these systems.
1. The Nervous System.—The nervous system is the coördinating arrangement of nerves and their processes. It makes possible the necessary continuous adaptation of muscles and glands. For convenience we may divide the nervous system into two major divisions: the central or cerebrospinal, and the autonomic. These, however, are not separate but closely allied organizations of neural tissue.
The gross structure of the complete nervous system reveals the cerebrospinal or central system to be composed of the spinal cord' and the brain. The brain is divided into three major sections: hind-brain or brain stem, the mid-brain, and the fore-brain. The most important portion of the fore-brain consists of the cerebrum. From the central system proceed thirty-one pairs of spinal nerves and twelve pairs of cranial nerves reaching out over the entire body.
The autonomic system consists of a double chain of nerve-ganglia and nerve-fibers extending on both sides of the backbone from the base
( 42) of the brain to the end of the vertebral column. These ganglia are connected throughout with the central nervous system. Their function will be discussed below.
a. The Reflex Arc as a Basic Functional Organization o Neurons. — The adjustment of the organism to its environment is controlled through the nervous system centralized in these larger units. It is through the coördination of muscles, tendons, and glands that bodily movement in reference to the environment takes place. Both internal and external stimuli impinge on the neural-muscular-glandular system, and the transmission of nervous energy sets off various forms of activity. The nervous system can not be properly understood without reference to both the inception of this action and its carrying-out. The nervous system is nothing but a highly specialized organization of tissue making possible more effective irritability, modifiability, and reaction in the organism. In the higher animals, including man, the taking-up of stimuli is facilitated by the receptor organs—the sense organs—of the body. From the receptor the impulse is carried over a nerve called the afferent or receptor neuron to the central or adjustor neuron located in the spinal cord, hind-brain, mid-brain or cortex, and thence outward to the motor or efferent neuron which links up with the response organ—muscle, tendon, or gland. These three neurons—afferent, central and efferent—constitute the fundamental reaction unit of the nervous system. The afferent or receptor neuron is a kind of private pathway leading from the sense organ or receptor to the central neuron system. This central switchboard, as it were, makes possible the direction of the nervous impulses outward to a large number of accessible efferent or effector neurons ending in muscles, tendons, or glands. In contrast with the privacy of the receptor process, the effector processes may be considered property common to the whole range of sensory or receptor pathways; that is to say, a visual, auditory, tactile, or other sensory stimulation may lead to innervation of the same muscle or gland, because the central neurons make possible the convergence of any one or a number of these private or specialized neural impulses from the sense organs upon the final common pathway to muscle or gland. For our purposes this is important because it indicates how varied the stimuli may be in producing similar or even identical responses. At the simplest level of reflex behavior, such as, the knee jerk or reaction to painful, cold, hot, or other direct stimulus, perhaps only three neurons are involved. In
( 43) the higher functions, habits and associative thinking, hundreds or even thousands of neurons no doubt come into play. Yet the basic threefold conduction principle holds throughout. This functional unit of reaction is termed the reflex arc. In the higher activities the brain plays a very important rôle in shunting the impulses into various paths and ultimately into complex motor responses. The cerebrum, in particular, functions to control and integrate the impulses from the receptors into more and more complicated action patterns. The whole complexity of higher behavior— habits and associative thinking—is dependent on this cerebral control.
We must emphasize the integrative nature of all reactions. The simple explanation of the action of the reflex arc found in some of the behavioristic accounts frequently ignores the fact that the organism-as-a-whole is involved in behavior. The neural-muscular-glandular system operates more or less in a unitary manner in the presence of stimuli or situations. The notion of three distinct units of reaction working together in additive fashion does not seem to be borne out by the work of Coghill on the development of the reaction system or by that of Lashley on the place of the cerebrum in learning. For expository purposes, however, we may describe the three phases of the total stimulus-coördination-response system.
The fundamental unit of the nervous system is the neuron with its nerve processes, axons, and dendrites. These neurons are hitched together in more or less definite reaction patterns. Some exist at birth; others are built up through learning. It is not necessary here to describe the histological sections of the nerve and its fibers, or to discuss the nature of nervous impulses. For this purpose the student may consult the standard works on neurology. The significant fact is that the organization of the functional unit or reflex arc is related to the simplicity or complexity of reactions. There are literally hundreds of bodily reflexes concerned in digestion, respiration, circulation, and elimination, and in the biological protective work of the organism which are laid down before birth. There are also a great many uncharted reflex arcs which are coördinated and integrated together in the course of learning. This process of integration takes place very largely through the mediation of the fore-brain, but it
( 44) must always be borne in mind that the habits and associative, integrative processes which are made possible through the fore-brain, are carried into action through the lower brain centers and the spinal cord processes.
b. The Receptors or Sense Organs: The receptors may be classified as exteroceptors, interocepters, and proprioceptors. The first consist of the external sense organs: vision, hearing, smell, taste, tactile (pressure), external cold, warmth, and pain. Vision and audition are sometimes called distance-ceptors because the stimulus need not be in direct contact with the organism at all. The interoceptors consist of the internal, systemic, or visceral sense organs which are closely linked with digestive and other vegetative functions and are distinctly significant in feeling and emotion. The proprioceptive organs are found in the semicircular canals and in the muscles, tendons, and joints. The first gives awareness of equilibration. The latter give rise to sensations of movement. The sensation is called kinesthetic (from the Greek, meaning sensation of motion). This sense is particularly important in learning, and it plays a distinct part in the formation of motor habits and in vocal responses.
In social behavior all of these sense organs play a rôle. As we shall observe, some of them, such as visual, auditory, and tactile, the systemic and proprioceptive, have more place than others. In certain types of social interaction some are distinctly significant. Hearing and seeing are especially important in person-to-person interaction. Yet the systemic receptors and effectors also have a definite place in giving us the feeling-emotional background behind all of our social behavior; and in the early intimate social contact of infant and parent touch plays an important part, as do smell and temperature senses also. The latter also have a definite rôle in love-making—a distinctly social activity.
c. The Effector Organs: The effector organs are the muscles and glands. They are set in operation by the efferent neurons. Muscles are of two sorts: striped, and unstriped or smooth. The former are concerned with overt, bodily movement, and the maintenance of posture. The latter are found in the digestive and other visceral organs, and are related to the more vegetative functions of the body. The glands are of two types, duct and ductless. Their muscular organization is of the unstriped type. The duct glands are concerned directly with digestion and elimination. The salivary, gastric, tear, and sweat glands are of this sort. Their products
( 45) reach the, appropriate parts of the body through the ducts leading from the glands. Still others, such as the sex glands, both energize the body and serve the purposes of reproduction. The ductless glands throw their substances, hormones or autocoids, directly into the bloodstream. Some of these glands, such as the thymus, the thyroid and pituitary, have a distinct place in bodily growth and in the maintenance of certain morphological proportions. Others have an energizing effect; the adrenals, for instance, stimulate the release of blood-sugar from the liver and otherwise increase bodily activity. The ductless glands are peculiarly significant in emotional expression.
d. The Central Nervous System.—The cerebrum is the seat of the central neurons which make learning possible. A large part of the cerebrum is taken up with association neurons and their nerve-fibers in a great network of relations. The receptor neuron is a single conduction path which leads into a vast system of conductive paths made up of central neurons. In contrast with the receptor schema, the latter may be said to be a system of multi-pathways made possible by a rich array of synaptic connections. The potential connections of this central or cortical system are manifold to an extent little realized. From the receptor neurons the impulses may radiate in many directions. In the case of general convulsions induced by strychnine poisoning the impulses discharge into practically every muscle and effector organ in the body. Ordinarily the irradiation is limited to the ranges laid down by native and especially by acquired connections. It was once thought that various areas of the cerebral cortex were highly specialized as to function. One region was believed to have to do with verbal speech reactions, another with written speech, another with audition, and so on. There is doubtless considerable localization of function, as is shown by clinical data on aphasias. Yet the present evidence seems to be that the whole cerebrum operates in most complex behavior with focal centers at any particular time or in reference to particular situations. Lashley has shown that after extirpation the alleged functional areas may be replaced by others through a process of re-learning.
The cerebral cortex is the seat of learning. The receptor and effector ends of the arc are not modified, but the direction of the efferent impulses may be controlled by changes made in the central neurons. As Herrick states:
All functions of the nervous system are facilitated by repetition, and many such repetitions lead to an enduring change in the mode of response to stimulation which may be called physiological habit. This implies that the performance of every reaction leaves some sort of a residual change in the structure of the neuron systems involved. These acquired modifications of behavior are manifested in some degree by all organisms, and this capacity lies at the basis of all associative memory (whether consciously or unconsciously performed) and the capacity of learning by experience. This modifiability through individual experience is possessed by the cerebral cortex in higher degree than by any other part of the nervous system; and the capacity for reacting to stimuli in terms of past experience as well as of the present situation lies at the basis of that docility and intelligent adaptation of means to ends which are characteristic of the higher mammals. It is a fact of common observation that those animals which possess the capacity for intelligent adjustments of this sort have larger association centers in the cerebral cortex than do other species whose behavior is controlled by more simple reflex and instinctive factors, that is, by inherited as contrasted with individually acquired organization. This is brought out with especial distinctness by a comparison of the brains of the higher apes with that of man. In our own mental life we recognize the persistence of traces of previous experience subjectively as memory, and memory lies at the basis of all human culture. From this it follows that psychological memory is probably a function of the association centers; but it must not be assumed that specific memories reside in particular cortical areas, much less that they are preserved as structural traces left in individual cortical cells, as has sometimes been done.
Correlated with the associative-learning and retentive function of the cerebrum, is the important inhibitory function. The lower reflex levels of behavior may be termed impulsive. Where the cerebral cortex operates, the behavior is indirect and controlled. The function of the cerebral cortex is, then, not only to give more adequate direction to response, but to inhibit the more impulsive, rapid responses of the lower centers.
The cerebral cortex is particularly concerned in the higher functioning of the organism. Social experience and the building of culture are absolutely dependent upon the operation of the higher brain centers. Throughout the whole range of materials dealt with in this book it must be recognized that our social behavior—language, social intercourse, following of fads and fashions, crowd action and the development of public opinion, the acquirement of cultural norms, prejudices and the techniques of survival—could nut go (.)it without the existence of the human brain. These
(47) complex activities result from various combinations of neuron processes in the cerebral cortex, related, of course, to the afferent processes on the one side, and to the efferent ones on the other. It is the cerebral cortex as coördinator and integrator, however, which is important for us. Even though the action of the basic reflex arcs is mediated through the lower brain centers and the spinal cord—such activity as is involved in hunger, thirst, sex, crying, and emotional responses in fear and anger—still these activities are modified, held in check, and integrated with learned behavior through the function of the cerebral cortex.
Man's superiority over the lower animals and over his environment, therefore, rests upon the heightened organization of behavior made possible through the cerebral cortex. On the side of original tendencies man does not differ greatly from his mammalian forebears. But the cerebral cortex makes possible extensive and long-continued learning. In the case of the fundamental reflexes, man inherits these, as do other animals, from his ancestors. In the case of social-cultural experience, these come to him through acquirement or learning. In other words, not biological, but social-cultural heredity dominates man to an ever-increasing extent. Hence whatever there is of social and cultural change depends, not on alteration of the spinal reflexes, but on modification and elaboration of reflexes controlled by the central neuron system of the cerebrum.
Nevertheless, the vegetative system lies at the roots of all this modification and elaboration. We can not understand man's social interaction, or even his culture which is a precipitate of this, without taking into account the fundamental features of his biological urges or bodily demands. These functions are carried on by the autonomic system in corroboration with the central system. Whatever we may say of the profound modifications in man's nature due to social and cultural conditioning, we must remember that he still remains an animal with appetites or urges which require satisfaction. These processes are basically related to the autonomic system.
2. The Autonomic Nervous System.—The autonomic system is not independent of the cerebro-spinal system. The two are intimately related and doubtless grew up together . The autonomic system is a part of the
( 48) peripheral neuron system. The central neurons all lie within the cerebrospinal system, as do those from the peripheral exteroceptors and proprioceptors. The function of the autonomic system, as we noted above, is to supply the visceral organs with nervous connections. Its receptors lie principally in the muscular and mucous lining of the internal organs. They are stimulated by the positions or postural tensions of these organs. On the other hand, the autonomic efferent fibers set up contractions in the smooth or unstriped muscles of the viscera. In short, the reactions of the autonomic system are largely those of tension or posture rather than of movement, as is the case with the striped muscles controlled by the efferent neurons of the cerebro-spinal system.
There are three major divisions of the autonomic system: the cranial, the sympathetic, and the sacral. Each of these divisions is made up of a series of related neural processes, leading to and from the visceral organs, via a series of ganglia, through the cerebro-spinal system. The cranial division arises from five of the paired cranial nerves. The nerves run to the eyes, the salivary glands, the heart, the bronchial tubes, and the digestive system. The cranial segment serves the organism in controlling the pupillary contractions of the eyes and the glandular and muscular activities involved in digestion. This division functions in emotional responses connected with the satisfaction of hunger and thirst. The general bodily tone correlated with it is pleasant.
The sympathetic division is made up of ganglia and autonomic fibers associated with the spinal nerves found in the thoracic and lumbar regions. The nerves supply the sweat glands, the hair of the body, and the peripheral blood vessels. Others run to the heart, the lungs, the digestive tract, and other visceral organs. Some sympathetic fibers also run to the organs of sex and elimination. The sympathetic system is concerned with speeding up the heart action, constricting the blood vessels, inhibiting the digestive processes by constriction of the smooth muscles, and stopping the flow of digestive glands. This system plays a distinctive rôle in the emotions of fear and anger. An unpleasant organic toning tends to be associated with its operation.
The sacral division is made up of fibers and associated ganglia connected with the sacral segments of the spinal nerves. The fibers connect with the organs of defecation, urination, and sex. The functioning of the sacral division is connected with processes of bodily elimination and sexual activ-
( 49) -ity. Under normal conditions these activities produce a decidedly pleasant toning.
It must be pointed out, moreover, that the cranial and sacral divisions operate in antagonism to the sympathetic. When either of them is in operation, the sympathetic is inhibited. When the sympathetic comes into play, there is a blocking of the cranial or sacral division. For instance, in fear, the sympathetic may serve to release the sphincter muscles controlling defecation and urination, just as it acts, in an opposite manner, to inhibit the digestive processes. The cranial-sacral divisions are related in function to hunger, sex, and bodily elimination, the sympathetic to the fundamental emotions of fear and rage. The former set may be considered positive and pleasant in function, the latter negative or protective and unpleasant. We shall return to this matter in our discussion of the emotions. The schematic figure on the following page gives an idea of the distribution of the autonomic system in relation both to the central nervous system and to the various internal organs which it controls.
It must be borne in mind at all times that the autonomic and the central nervous systems function together. There is always a distinct link-up of the reflexes controlled through the cerebro-spinal system, such as the muscle groups of the legs, arms, head, trunk, and throughout the entire somatic system, and the autonomic reflexes of the visceral region. For example, a stimulation of the ear by a loud sound leads over a central reflex arc to produce movement of the head, arms, legs, and trunk, but at the same time it sets in operation the sympathetic division of the autonomic system and produces those bodily changes which are evidenced in crying, blanching of face, inhibition of the digestive processes, alteration in heart action and in respiration.
Any peripheral or internal stimulation, therefore, has possible autonomic connections with the visceral system. Throughout our entire treatment of social behavior we shall see how both central and autonomic functions are correlated. The first essential point for us is that no major action takes place in the body which is not mediated through the nervous system. Secondly, the fundamental drives or urges or tendencies to behavior rest in the vegetative system in which the autonomic plays a large part. However remote the behavior may seem from this substratum, in the last analysis no description and interpretation of social behavior is complete which ignores this fact. While it is clear from much evidence that the autonomic func-
(51) -tions may be conditioned, modified, and partially controlled by the action of the cerebro-spinal system, it is not altogether clear that the central system is dominant over the functioning of the autonomic system. In other words, the social as well as the biological evidence supports our fundamental thesis that emotions, feelings, and instinctive or prepotent reflexes are the cornerstones of behavior on which the superstructure of human personality is constructed. Man is always a feeling and emotive being. Only in a secondary way is he an intellectual, rational, and deliberative person. To say this is not to fall into the error of holding that the autonomic system completely dominates the cerebro-spinal, but rather that the two are inextricably correlated. To deny the place of the cerebral cortex in the modification and elaboration of behavior is foolish. Still it is equally unwise to deny that the foundations of human motivation lie in the emotions and feelings associated with the basic vegetative demands of the organism.
C. The Levels of Reaction.
If we move from a study of the general structure and function of the central and autonomic nervous system to an examination of the reaction levels of the entire organism, we are impressed with the fact that the complication of behavior is correlated with the number of reaction patterns involved. This, in turn, indicates the place that our dual nervous system has in the behavior of the organism as a whole. For our purposes we may mention three levels of behavior. These will be dealt with in more detail in subsequent chapters. The first of these is the reflex level, the second the level of habit, and the third the level of intelligence or associative thinking. In the first we include the basic vegetative reflexes of digestion, respiration, heart action, and bodily maintenance. Although these, as we have seen, are fundamental to all other action, we shall not discuss them further. Rather let us note briefly the more general aspects of these three levels of reaction as an introduction to the chapters which follow.
1. The Emotional-Instinctive Reflexive Level of Behavior.—From our animal forebears we have inherited certain fundamental behavior patterns, which lie at the basis of all others that are built upon them. These we refer to as the instinctive overt reflexes and the emotions, or covert reflexes. The latter seem to arise in those situations in which the overt reflexes of the organism are blocked by some condition in the environment to which the organism must readjust itself. The instinctive or prepotent reflexes and the emotions operate together in the survival of the organism at the purely biological level. Behavior here tends to be impulsive and direct. Since so much ink and paper have been dedicated to the subject of instincts, especially in reference to social psychology, and since the basic motivations for behavior do seem to lie in these hereditary tendencies, the next chapter will be given over to a more extended discussion of instincts and emotions.
2. The Level of Habit Formation.—Although man begins the struggle for existence in terms of his emotional and innate reflexes, experience soon organizes these tendencies into habits. The capacity to form habits, to arrange the reflexes into new patterns, to integrate the new patterns into larger patterns, rests on the inherited nature of man. Thousands of reflex coördinations are possible because of the modifiable nature of the central neuron system.
3. Intelligence and the Higher Levels of Behavior.—Man, however, does not stop with merely forming habits on the basis of crude trial and error. By development of his cortical control he can anticipate his behavior. The development of his fore-brain has meant that he can make associations in his responses which are not permitted the lower forms of life. These higher integrations rest upon better perceptual ability, upon a more highly developed associative capacity, and a better retention of things learned. The correlation or integration of these into concepts and abstractions, in which language plays such a rôle, marks the highest complexities of man's nature. The social life of man would remain on a level with that of the anthropoids were it not for these higher capacities. Certainly culture, as we know it, even of the most primitive peoples, would simply be impossible without these more developed capacities. The most delicate associations of scientist or artist, the most abstract ideas of the logician or mathematician, the most refined metaphysics—would not be possible without the complex organization of the brain.
D. The Cycle of Activity.
All of these levels of reaction are related fundamentally to the cycle of life activities set up by demands of the vegetative system. Through the changes in the vegetative organization tensions ensue which demand release. Much of the reflexive, habitual, or intelligent behavior of the individual is given over to the accomplishment of this release of tensions. There is first the tension, then restlessness and movement toward a stimulus or situation which will release the strain. The stimulus, if adequate, brings about the more or less complete release of these tensions, and the organism slips back into a stage of complacency or vegetative adaptation to the environment. Craig has laid out a scheme of fundamental activity along this line in his theory of appetites and aversions as the dynamic force in behavior; and the appetites or aversions rest for their inception on the vegetative system. The following is slightly modified from Craig to take into account the factor of visceral tensions in which the autonomic system plays such an important rôle.The type cycle would show four phases as follows:
Phase 1: Presence of a visceral stimulus or tension, and absence of external stimulus to satisfy this physiological state. Restlessness, varied Movements, effort, search. Incipient consummatory action.
Phase II: Reception of the appeted stimulus or release of the tension by elimination or other response. Consummatory reaction in response to this stimulus. State of satisfaction. No restlessness or search.
Phase III: Surfeit of the said stimulus, which has now become a disturbing stimulus. State of aversion may ensue in order to escape or avoid the surfeiting stimulus. Restlessness, trial, effort, directed toward getting rid of stimulus.
Phase IV: Freedom from the said stimulus or tension. Physiological state of rest and relaxation. Inactivity of the tendencies which were active in Phases I, II, III . 
Actually the third phase may not be apparent or may not even occur. In the case of bodily elimination the surfeit of stimulus rarely occurs. The whole cycle may be thought of as a method of releasing tensions and such release occurs through the complete response—an integrated activity of highest importance to the balance of the organism. This freedom from strain is a pleasant, serene state, a sort of complacency in the organism
(54) which persists until a new cycle ensues. Much of the problem of maladjusted personality rests in the failure of the vegetative tensions to find socially acceptable releases. The partial response is unsatisfactory. Too frequently a more or less complete blocking of the releasing responses leads to pathological developments.
In the course of life the purely reflexive releases of the tensions are modified profoundly by personal-social and cultural conditioning. From birth on, these forces begin to operate. The tensions of adult social life are many and varied. Much of our material will be concerned with a revelation of the manner in which these conditionings modify and direct the course of the vegetative demands of the organism. Frank has discussed the subject in an effective manner:
Social life is a product of learning to manage the visceral tensions in accordance with the requirements and usages of the family and of the social group. This learning takes place through the instruction given to the young, who, almost from birth, are subjected to adult supervision in the adjustment of these tensions, and in general the child is expected to learn to sustain, diffuse, and release his physiological tensions only as and if the group-sanctioned occasion and custom permit.
The first problem of this tensional control arises from the parental management of feeding, which requires the child to learn to sustain the hunger contractions of the stomach until the appropriate time for feeding arrives. He must learn, not only to sustain those tensions, but to regularize his metabolism so that he can assimilate and release sufficient energy to endure the intervals between feedings. Later he must learn to obtain food or the means thereto by work or effort undertaken in anticipation of these recurrent hunger tensions.
The second problem of tensional management confronting the child is to learn how to sustain the pressures arising in his bladder and rectum until the appropriate time and place for their release are presented. This problem calls for a progressive raising of the threshold of the sphincters and learning to respond to the accumulating pressures sufficiently early to permit the necessary warning to parents, and, later on, the appropriate activities for eliminations. To meet this problem adequately the child must learn to sustain these pressure tensions in accordance with the requirements of the group life. This and the hunger problems may be taken as the prototypes of his adult behavior, since they involve not only the ability to sustain tensions but to use these accumulating visceral tensions as the cue or stimulus to whatever activities are necessary to reach or achieve a group-sanctioned release. This means learning to deal with present situations and stimuli with due regard to their more remote consequences and their utility or disutility for tensional adjustment. In other words; growth to maturity calls for an increasing ability to respond to absent or re-
(55) -mote situations which are adumbrated by the rise of visceral tensions and by their situational antecedents.
The next problem facing the young child is to learn the inhibition of the sympathetic reaction, which we call emotional response, evoked by shock, surprise, pain, and ambiguity or uncertainty. When stimuli of this character are received, the organism, as Cannon and others have shown, is profoundly altered physiologically, the sympathetic division of the vegetative nervous system becoming dominant.
The child must also learn to employ the verbal stimuli of approval and reassurance as substitutes for the close tactual stimuli received in infancy, as in mothering, caressing, and cuddling. Along with that he must also learn to respond to disapproving verbal stimuli as substitutes for physical coercion and the blocking of responses not meeting with adult assent.
Finally, at the beginning of adolescence, the specific sex tensions make their appearance and present new problems of tensional management, since the youth and maiden, in Western society, are expected to refrain from release of sex tensions until they have reached full maturity. This means that they are called upon to sustain and diffuse their sex tensions and to avoid any approach to the person of the other sex.
These lessons begin during the first and second years of life and call for the management and control of the several varieties of visceral tensions arising within the child. As the infant grows older and achieves locomotion he is brought into contact with an ever widening environment of things and persons presenting the stimuli for immediate release of these tensions or for arousing emotion. The same kind of problem is continually presented. Under the tutelage of parents the child must learn to refrain from approaching and using these stimuli, however freely exposed to his approach and despite the urgency of his visceral tensions. If hungry, he must learn to sustain his stomach contractions and forego the easily appropriated food around him unless and until the elders give approval. If other persons intervene between him and the stimuli he seeks, or otherwise interfere with him, he must learn to refrain from approaching them or from attempting forcibly to remove them, just as he must learn to desist from approaching them for any direct tensional release. In other words, he must learn that each individual enjoys a varying degree of immunity from approach or invasion, which he must observe in all his behavior. Again, he must learn that objects and situations are likewise to be left untouched because they also are not to be approached or used, however strongly they exhibit stimuli to tension release. Such lessons involve the inhibition or repression of the naïve response, which is gradually learned under adult instruction: the parents frustrate the naïve response or inflict pain after such forbidden responses until the child learns to observe the parental prohibitions even in their absence. In other words, the child is negatively conditioned until the stimuli of these things and persons are rendered partially impotent. To put it another way, the child, under the guidance and instruction of elders, learns to observe the differential taboos upon
( 56) people and things which we call the sanctity of the person and private property. Private property is thus not a thing, but the learned behavior toward things.
We see then in early childhood how the institutional patterns of behavior are inculcated in the child as he learns to manage his tensions in accordance with the prohibitions and sanctions of the family life. The cultural tradition will, of course, set the general patterns, but the individual family life and circumstances will give these patterns their individual character and variations.
The management of tensions and the capacity to maintain the physiological energy for achieving a remote objective (i. e., responding to a distant stimulus) are achievements of no mean order. For they require, not only effort and the energy to sustain that effort, but the ability to forego the relaxation of tensions that are so ready to release to the first available stimulus. All the social virtues of courage, perseverance, strength, loyalty, virtue and chastity, and their multitudinous synonyms and derivatives are but aspects of the management of tensions. Hunger, pain, emotion, such as fear and panic, and sex desire, are all ready to betray man from pursuing the long-term achievements and goals set by culture. To raise crops and animals, to build houses and buildings, to establish a family and to nurture the young—these call for endurance, patience, and the postponement of immediate consummations for the future achievement. Everywhere we find man has invented methods of sustaining his efforts and reinforcing his continence against the ever present stimuli to relaxation. We call these aids to his long-term pursuits and tensional management his values. For whatever a man uses to keep himself at work, to ward off the panic or the lure of quick consummation while he carries on, is a value. Put in another way, we might say that any behavior addressed to a remote stimulus is a form of value behavior. 
Behavior, in short, begins in physiological reactions to organic urges or tensions, but becomes organized through learning so as to satisfy not only these direct demands but all sorts of indirect needs which are socially acceptable and which make possible participation in group life.
A. Further reading: Source Book for Social Psychology, Chapter IX, nos. 55, 56, pp. 194-208.
B. Questions and Exercises.
1. Discuss questions and exercises in assignment in Source Book, Chapter IX, p. 217, nos. 1-3 only.
2. What are the major criticisms of the older view in psychology which sepa-
(57) -rated sharply heredity from environment? What has Child contributed to this problem?
3. What are the basic neurological structures and functions?
4. How does the nature of the receptors determine the world to which we respond? Illustrate from the case of the blind, the deaf.5. How do the cerebro-spinal and the autonomic systems interact?
6. Illustrate behavior at the reflexive-emotional level. At the habitual level. And at the level of intelligence.
7. Illustrate cycles of activity at each of these levels.
8. Why must we take the social-cultural environment into account in describing and interpreting behavior? Would not a study of physiological tensions and their modifications be sufficient?
C. Topics for Class Reports and Longer Written Papers.
1. Review Carmichael's "Heredity and Environment: Are they Antithetical?" Journal of Abnormal and Social Psychology, 1925, vo1. XX, pp. 245-60.
2. The contribution of C. M. Child to social psychology.