Instinct: A study in social psychology
Chapter 3: The Organic Bases of Action
Luther Lee Bernard
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The chief constituent of living matter is protoplasm. In the animal organism this takes on several forms which are more or less closely correlated with the functions of structures. While all protoplasm has the distinction of being more highly or complexly organized and less stable in its organization than non-living matter, certain types of it are much more sensitive to external influences than others. Thus, of the bones, glands, muscles and nerves, the last named are the most sensitive of all and have been specialized to the function of communicating conditions and stimuli from the environment to the body or from one part of the body to another. In the higher living forms the brain, and especially the cerebral cortex, serves as the organ or organization for clearing, connecting and evaluating these transmitted impulses through the animal organism to aid it in making its adjustments to its environment.
Correlated with the irritability of protoplasm is the fact of the self-activity of the organism, due to metabolic processes.[1] The organism is so constituted or organized that it is active. It is never passive, except in death. In its early life the metabolism is especially active and the organism is particularly restless. But it is in this period also that its movements are least accurately and successfully developed or coördinated within itself and with reference to external objects. Its movements are, with some exceptions, what are generally known as random movements. But even at this stage of development
(39) the general conditions of movement are fairly well determined, and those conditions of movement which have already been determined at this stage are apparently in the main determined by heredity. The general shape, size, and placement, as well as structural qualities, of the bones, muscles, glands, and the lower neurons are inherited. Action, whether its pattern has been inherited or organized from fixed or random movements largely with the aid of environmental pressures, must make use of these organs or structures. It will be limited in its direction and power by the functional organization and the competency of the structural materials, although this competency is much more susceptible to environmental organization and modification than is the functional organization, at least in the larger and basic aspects. Even such seemingly insignificant details as length of bone, types of joints, which limit or control the direction of movement, or the conditions under which glands are and are not able to secrete, or the fatigue conditions of muscles and nerves, must not be neglected in taking account of the inherited— and acquired— conditions of activity.
The irritability of protoplasm is the quality which enables the organism to act economically and, in the case of higher organisms, intelligently. It not only makes possible the reception of the stimulus which sets inherited action patterns into functional activity, but it also serves as a means by which the grouping or organization of the random or uneconomical movements into functional habits as wholes may take place. When any organ comes in contact with an object this sensitivity or irritability establishes the condition known as the stimulus and communicates the impression to other parts of the organism. This establishes connections throughout the organism, that is, ties it up as a functioning or intercommunicating whole with reference to this object.[2] In this way, the random
(40) movement, and the metabolic energy back of it, come to be replaced by a definite stimulus-response process utilizing the energy of metabolism. Gradually, as many such acquired connections are made with the aid of the sensitivity and communicability of protoplasm, and as more and more random movements are absorbed and replaced by definite coordinations, the organism becomes a functional unity or functional whole, from the standpoint of acquired action patterns as well as from that of inherited mechanisms. Necessarily, these two types of action patterns— the acquired and the inherited— are developed in fairly close conformity to each other. That is, the habits formed out of random movements adapt very largely to preëxisting inherited patterns, on the one hand, and the inherited patterns are also modified to meet the demands of the environment as expressed through the habit formations.
Needless to say, not all habits are formed in the virgin way here indicated, that is, directly and solely from random movements. Habits are likewise organized out of any smaller units or fragments of action patterns. Reflexes or chains of reflexes (instincts) may be requisitioned in the habit-forming process. Chains of reflexes may be broken up into their constituent parts in order that the new habit construct may make use of such elements as it needs. In the same way, previously formed habits may be utilized as a whole or broken up before utilization. Random movements may perhaps properly be regarded as reflexes, or, possibly, in some cases, as the fragments of disintegrated instincts. But, for the most part, the random movement proceeds from within and is dependent less upon an external stimulus than upon an internal overflow of energy which incites the muscles, or glands, or, perhaps, even the neural processes to random action.[3]
In the higher organisms most of this activity is mediated
(41) through the nervous system, which acts as a carrier or transmitter and transformer of the stimulus. This is not true of the lowest organisms. The muscles and the glands evolved before the nervous system.[4] But as the organism became more complex and as its sensory system rendered it susceptible to an ever-widening environment, the nervous system appeared to facilitate the transmission of impulses and finally to coördinate and control them.[5] The nervous system not only rendered the organism more sensitive to stimuli, but it also made possible a much more rapid and a much more widely distributed transmission and transformation of stimuli into responses. And in the later stages of its development it has made a selective transmission of stimuli highly effective in place of the old relatively more uniform distribution of stimuli to all parts of the organism. Even where there is a tendency to widely diffused distribution of the stimulus through the tissues which function more slowly than the nerves, the greater rapidity of transmission and the greater effectiveness of neurally selected and controlled stimuli easily correct the evil of diffuseness. This control and correlation of neural transmission takes place in the higher nerve centers, in the cerebral cortex of the brain.[6]
This greater sensitivity to stimuli and this greater rapidity, breadth and coördination of transmission of the stimuli are essential to the efficiency of the higher organisms. Their sensitivity to expanded environments, due to primary and secondary (cultural multiplication) developments of the senses, renders it possible and necessary for them to handle 3 a much greater volume of stimuli in a much shorter period of time and much more accurately. This fact may be illustrated especially from the life of man. The environment which presses down upon him offers him an enormous volume of stimuli from all directions. He has so multiplied the mechan-
( 42) -ical and psychological aids to perception that he is literally swamped by the pressures of his social, and especially of his psycho-social, environment. As a result he must meet situations rapidly and accurately or fall behind in his competitive struggle for advantage, or even pay the extreme penalty for incompetency with his life. What is true of man is less characteristic of the animals below him, but it is the more nearly true of them in the degree to which they approach his plane of development. [7]
In man relatively few significant activities take place without neural mediation and these are primarily visceral. Herrick points out that, "Many of the visceral functions can be performed quite apart from any nervous control whatever by the intrinsic mechanisms of the viscera themselves." [8] Among these may be mentioned the automatic heart beat, the ordinary processes of digestion, the secretive action of the pancreas, and the interfunctioning of uterus and ovaries in menstruation.[9] But while the nervous system is not dispensed with in any considerable number of important cases, it is by no means the sole functioning agent in most cases. The physiologist and the psychologist are learning to take into consideration many conditioning factors in activity, especially the secretions of the glands and the available energy supply from metabolism. This recognition has not always been given. As Paton says, "Practically no attention was (formerly) given to the fact that such organs as the liver, suprarenals, thyroid, and sexual organs, by the effect of their secretions upon the activities of the nervous system, influence the sequence of the moods, trains of thought, and general trend of activities." [10] Paton is corroborated in this respect by Her-
( 43) -rick who states that, "the visceral functions as a whole are of enormous importance, not only in the maintenance of the physical welfare of the body, but also as the organic background of the entire conscious life."[11] These are facts which have been emphasized especially by the newer physiology and the newer psychology, not neglecting those who have worked in the somewhat amorphous field of endocrinology.[12]
The nervous system is generally divided into two great divisions, "the central nervous system, or axial nervous system, comprising the brain and spinal cord, and the peripheral nervous system, including the cranial and spinal nerves, their ganglia and peripheral end-organs, and the sympathetic nervous system."[13] Within the peripheral nervous system lies what has sometimes, especially more recently, been called the autonomic nervous system,[4] because it functions primarily automatically. It is an older phase of the two systems and came into existence as a means to helping the organism make immediate and direct adjustments to its environment. It has been called the vegetative system by some investigators in recognition of this direct function and has been divided into the vagus, the sympathetic and the sacral systems.[15]
( 44) This system is built around the vital functions. It literally grew around the digestive tract, the respiratory and circulatory systems, the reproductive and excretory apparatuses and finally the lower exteroceptive senses. Paton says of it that it "still has very important functions to perform in man, as it coördinates and regulates organs connected with the intake, assimilation, and storing of energy, including the digestive, circulatory, and secretory systems, sex organs, and those regulating growth, together with the supervision of metabolism for emergencies, and the enormously important postural tonus of the muscles." [16]
The three divisions of the autonomic system may be said to correspond in a rough and major manner to the three great functional interests of food or the means of organic sustentation, fighting and sex. Woodworth says, "The upper division (vagus), from the medulla, favors digestion by promoting the flow of gastric juice and the churning movements of the stomach; and at the same time it seems to favor the comfortable, rather lazy state that is appropriate for digestion. The middle division (sympathetic) . . . . checks digestion, hastens the heart beat, and stimulates the adrenal glands to rapid secretion, thus giving rise to the organic condition of anger. The lower division (sacral) has to do with the bladder, rectum and sex organs, and is active during sex excitement." [17]
( 45)
Because of its early origin[18] and its simple and highly standardized or fixed functions in promoting and conserving the vital processes, more definitely inherited processes or connections are found in this autonomic system than in the remainder of the nervous organization. This is the true and original home of the reflexes, instincts and tropisms. The organic conditions of respiration, food taking, excretion, circulation, reproduction were standardized long ago when the organism itself was standardized. Neither the organism itself nor the environment which conditions these processes within the organism changes rapidly enough to require any highly alert intelligent control over them. The result is that most of them are highly automatic. It is here that we find the best examples of the definite stimulus producing the definite response with a minimum of modification and a minimum of consciousness. Such reflexes and instincts as the winking of the eye, dilation of the pupils of the eye, stimulation of the heart, dilation or closing of sweat glands and the secretion of the major glands and ductless glands of the body, the processes of swallowing, digestion, breathing, excreting, etc., are examples of the inherited functioning of this system. It ordinarily requires, or permits, relatively little interference from the central nervous system where intelligence resides. But such interference is upon occasion consummated, perhaps more often indirectly than directly.[19] The direct interference of the central with the autonomic nervous system appears to take place when the organism as a whole is in danger from without or when it requires all of its energies immediately for protection, or in some other crisis. In such cases the startled warning from without may cause digestion or other vital but temporarily unnecessary functions to be suspended; or it may quicken the response of the heart for a supreme effort of strength. Thus, on the whole, the vegetative or autonomic
(46) nervous system, perhaps best typified by the sympathetic system, may be regarded as an exchange or communicating system quite as much or more than as an organizing or control system. Certainly its control is characteristically automatic and does not directly involve the higher or conscious directive centers of the brain. The function of highly directive or conscious control belongs primarily to the central nervous system.[20]
However, the control functions of the autonomic nervous system are by no means unimportant. The autonomic is merely secondary in this respect to the central nervous system and its methods are more direct and less conscious. Paton says, in this connection, "This vast apparatus or autonomic system is a silent participant in the regulation and control of organized activities; but although silent it possesses extraordinary importance in providing means of adaptation, sometimes described as `unessential,' but which as a matter of fact are intimately connected with another apparatus of vital significance to the organism. The nervous supply distributed from this vegetative system to the various organs, such as the heart, lungs, thyroid, adrenals, etc., indicates the close relation of its functional control over the organs that have an enormous capacity for modifying the workings of the central nervous system, and even of interfering with life itself. This autonomic system regulates the affective life, and in this way determines character, temperament, and indirectly promotes or inhibits the higher intellectual function. Kempf has reminded us that the physiological divisions of the body, regulating the assimilation, conservation, distribution, and expenditure of energy and the elimination of waste products, act as one autonomic system." [21]
( 47)
It is not until the amphibians appear that those structural changes in the nervous system begin which later become the brain,' and the cerebral cortex probably first appeared in ani-
(48) -mals of the Triassic or Carboniferous periods of geologic development.[23] "The more primitive types of intellectual activity are useful merely for adaptations occurring within a very limited range, and practically little provision is made for the collection and recollection of experiences which are useful in the conservation of energy or life .[24] . . . All animals, below the reptiles, are practically entirely devoid of those special cortical mechanisms which greatly increase the capacity for combining and elaborating impulses and impressions transmitted by the sensory tracts to the brain."[25] As a result the reactions of these lower animals are primarily instinctive. The higher in the process of animal evolution we ascend the greater the extent to which the more complicated activities are centered under the dominance and control of the cerebral cortex .[26] The purpose of this organ is to give individual and social experience a chance to operate in making adaptations of the organism to the immediate environment by means of intelligent inhibition hand modification of previous tendencies.[27]
The brain, and especially the cerebral cortex, therefore appeared for the purpose of integrating, organizing and controlling the functioning of the organism in an increasingly complex and a rapidly changing environment more perfectly than had been possible with the autonomic and the rudimentary central nervous systems alone. just as there comes a time in animal evolution when, with increasing complexity of the organization of the body, "protoplasmic activities on the lower physiological level are no longer adequate to effect the integration and coordination of the more diversified functions to be performed in these complex organs" and the autonomous or peripheral nervous system is brought in to function in organization and control locally, so the complex organism finally has so many functions and adjustments thrust upon it that a cen-
( 49) -tral nervous system arises to make possible further correlation and control.[28] Out of the beginnings of this central nervous system arose a central group of ganglia which became the brain. This brain system continued to develop in size and in adaptation to its functions until it apparently ceased further organic or hereditary development about 25,000 years ago, or less, among the Cro-Magnon men.
One of the chief organs of control functioning in connection with the evolving brain has been associative memory, which enabled the animal to make available past experience through consciousness and unconscious habit adjustments, in addition to the slow method of the accumulation of inherited mutations or variations.[29]
The growing participation of the mental in addition to the purely biological in the function of controlling the organism may be illustrated by recalling some of the steps by which the higher control functions evolved. The cerebral cortex is the organ last to appear in the brain and it is here that the final correlations which figure in consciousness take place. The lower parts of the brain, especially the cerebellum and the thalamus serve largely as correlation centers for connecting the thinking section of the brain with sensory and motor organs.[30] The cerebellum especially "is the great clearinghouse" for all "afferent systems which are concerned in the proprioceptive functions, so far as these are unconsciously performed." [31] On the other hand, "the thalamus is in the human brain chiefly a sort of vestibule through which the systems of somatic sensory nervous impulses reach the cerebral cortex."[32]
Correlative evidence is to be had from the order of develop-
(50) -ment and the location of the sense organs. Besides containing "all of the most important higher correlation centers of the brain, " the cerebrum also contains the sensory centers of sight
and hearing.[33] These senses are the most highly evolved which are possessed by man. It is through them that he receives the vast bulk of those sensory impressions which he organizes into ideas, principles and laws. It is, therefore, through this avenue that the chief intellectual content comes .[34]
Herrick further explains the dominating function of the cerebrum, especially in connection with the cerebellum, as follows: "The correlation centers of the brain stem, and particularly those of the cerebral cortex, analyze the afferent impulses entering the brain and determine what particular reactions are appropriate in each situation. After the character of the movement has been determined in this way, the proprioceptive systems coöperate in its execution, and the cerebellum is the central coördination station for the proprioceptive reactions. None of its activities come into consciousness." [35] While the cerebellum appears much earlier, phylogenetically, than the cerebrum and "its functions are wholly reflex and unconscious and are concerned chiefly with motor coördination, equilibration, and, in general, the orientation of the body and its members in space . . . the cerebral cortex, on the other hand, is the organ of the highest and most plastic correlations, which are in large measure individually acquired."[36] Herrick adds elsewhere that "the cerebral cortex differs from the reflex centers of the brain
(51) stem chiefly in that all of its parts are interconnected by inconceivably complex systems of associational connections, many of which are probably acquired late in life under the influence of individual experience, and any combination of which may, under appropriate conditions of external excitation and internal physiological state, become involved in any cerebral process whatever."[37]
The obvious meaning of these two passages is that this cortical control system which dominates the activities of the higher organisms is primarily a habit or acquired system. The cortex was the last step evolved in the struggle for flexibility in neural control. It not being possible to secure the requisite flexibility through multiplying and fusing reflexes, the sensitivity of protoplasm eventuated into constructive intelligence enabling the cerebral cortex to exercise its control largely through thought. The advantages of such a type of control are obvious. A much wider range of stimuli can operate upon the control system, because the stimuli can be apprehended through the perceptual mechanisms and can be assembled from afar. Also, types of stimuli which would not register, or would be but slightly appreciated, under the dominance of unconscious controls, may acquire very great momentum and power under a conscious control system, because of the extreme delicacy of the recording conscious mechanisms and of their power to amplify the stimuli. These same stimuli can be stored, either in memory or in places of objective record, and thus remain operative over a very long period of time.
But how is this transference from an inherited or instinctive control system over to an acquired one accomplished , Of course the control processes of even the autonomic nervous system are not wholly instinctive or inherited. Jennings
( 52) tells us that the lowest forms of life show power of varying their reactions on the analogy of experience.[38] It is the nature of protoplasm to be sensitive to impressions and to carry some record of that impression for future use.[39] Even among plants and animals too low in the developmental scale to possess a nervous system responses occur "which appear to be dependent upon certain elementary forms of discriminative irritability or sensitivity."[40] Later, a crude mechanism of adjustment or nervous system appears and this is in time organized into the autonomic system. Here variant adjustments multiply by the aid of the impressionability of protoplasm, nervous and otherwise. But there is no evidence that consciousness, at least perceptual consciousness, is present as an aid to making habit modifications. It is only when the cerebral cortex appears in fairly well developed form that a sufficiently highly developed form of consciousness appears to entitle the control system to be called volitional. The variant element in control has, at this point among human beings, reached such a high degree of development that the organization is not necessarily determined from within the organism at all, but is so logically determined from external and internal considerations that we call it intelligent determination and apply to the causal process the term willed.
This explanation of the high degree of development of the variant or volitional element need not imply an explanation in terms of fiat or magic, or a theological or metaphysical account, at all. Herrick explains the whole thing in terms of conflict. He says that conflict is inherent in the cosmic process, or at least in the biological part of it, from beginning to end. This struggle is not alone between individuals or types, but it is also "between stereotyped innate tendencies or instincts and individually acquired experience," in which the latter has the advantage in so far as the environment is
( 53) complex and requires rapid and multiform adaptation. This conflict between instinct and habit occurs even among the protozoa. "And out of this inner conflict or dilemma intelligence was born. With the gradual emergence of self-consciousness in this process arises the eternal struggle with self . . . . Conflict, then, lies at the basis of all evolution, and the factors of social and even of moral evolution can be traced downward throughout the cosmic process. The social and ethical standards, therefore, have not arisen in opposition to the evolutionary process as seen in the brute creation, but within that process."[41] As Herrick suggests, the guiding intelligence, the so-called volitional element, in cortical control of the organism is not something imposed from without. It is rather something which grows up from within the life process itself; it is ultimately and finally dependent upon the original irritability or impressionability of protoplasm; its evolution from the primitive beginnings of crude protoplasmic irritability as viewed in the protozoa to the high degree o complexity which we call genius in the modern great leader or thinker is immense in range, but unbroken in process.
The process by which this greater flexibility of movement and adjustment is brought about is partly muscular, partly glandular, and by means of the grosser tissues and organic structures generally; but very slightly so. The flexibility arises primarily because of the fact of the existence of unconnected synapses in large numbers in the human cerebral cortex. Of the approximately nine billion cortical nerve cells a very large number are not completed at birth but develop and make their connections later.[42] Even after their main connections are made they are capable of some variability, for the dendritic processes appear to have a very wide range of possibilities in varying their connections. It is said that as many as sixty dendritic processes have been observed
( 54) attached to a single neurone, each process possibly representing a potential connection. It is also known that these dendrites relax and renew their contacts according as they are affected by fatigue or some other stimulus or condition.[43] It is supposed that at no time in the life of the organism are all of the neurones fully developed. Consequently the capacity for making new associations is never exhausted in any one. When it is reflected that consciousness accompanies these neural processes, it is easy to perceive how unlimited are the chances for multiplying ideas and willed or affectively supported plans and patterns.
One further problem from our point of view yet remains for consideration in this connection. What controls this conscious or thinking adjustment process? Is it the environment, including the psycho-social environment of custom and tradition, of institutions, of science even? Or is it the underlying instincts and reflexes upon which the conscious controls are built as variants? The answer to this question has profound significance for a theory of education or of social control. The instinctivists, fairly represented by McDougall,[44] maintain that the acquired elements in character or control are formed under the dominance of the instincts. The environmentalists maintain the opposite and look to the environment, especially to the psycho-social environment, for the formative factors back of the control organization. It is true that the central nervous system does not, at least in the lower stages of development, initiate orderly activity but that it comes into existence merely to control or direct it.[45]
But it is not necessary for it to initiate it; it does quite enough if it directs it. Paton's statement that "as far as we
( 55) are able to judge, it is the drive from the lower levels that decides upon the selection of paths in the higher planes,"[46] does not carry conviction. No doubt such lower drives do modify or help to form the organization of the higher or conscious controls, and some habits are shaped by instincts [47] but nothing seems clearer to unprejudiced observation and experience than the fact that instincts are constantly being modified or repressed or supplanted by habit organizations. It matters little if the instinct is in a measure taken care of by the control organization, either through sublimation or incorporation, so long as the social organization and not the instinct or lower nervous organization determines the plan of disposition. People must eat or perish and the desire for sex activity and companionship is sometimes and in some individuals very strong. No social system can disregard them entirely, but no rational control system will disregard them any more than it will be dominated by them. In so far as they conflict with other valued interests in society a compromise is necessary, not complete surrender; and, according to Herrick, it is out of this sort of conflict that intelligence and rational and ethical and social control arose. The conscious, willed control system centering in the cortex came into existence to prevent disastrous domination and to provide for intelligent adjustments. As Woodworth rightly says, the acquired elements in character are far more numerous than the inherited ones,[48] and collectively, if not always individually, they are also much stronger.
Both Herrick and Paton really testify to the truth of this contention in their statements. Paton says, " We have already remarked upon two of the functions of man's new brain, namely, to act as a transformer of the impulses streaming up from the old brain, and to hold these in check long enough to insure proper arrangement for the distribution of energy
( 56) without throwing too much energy into one channel. As the brain and nervous system developed, the centers for the older primitive protopathic sensory apparatus and stereotyped instinctive activities which were located in the basal ganglia, were covered over and reinforced by the complicated new brain or cerebral cortex. The addition of these areas with their so-called higher functions greatly extended the range of adaptation by utilizing consciousness. Under the old régime adaptation unattended by any sense of the perspective of events was sufficient to satisfy actual conditions, but with the extraordinary increased complexity of the integrations made possible by consciousness and the intricate epicritic system an entirely new set of functions was called into action. In man there still exists the old apparatus by which primitive instincts found expression, but with the growth of the neopallium, the new brain, the coordination of conduct and the domination of instinct by intelligence were insured." [49] The only question which remains is as to whether intelligence was created by instinct to serve its ends or by the increased pressures of the environment, to save the organism as then constituted from destruction. The growth of intelligence is itself conditioned on the increased recognition and appreciation of the environment.[50] In the individual development, as well as in that of the race, where the environment ceases to make demands or has never developed to the point of making demands upon the intelligence, the mental functions deteriorate or fail to develop and leave the control of the organism to the unrestrained exercise of the instincts. The meaning of culture is that man comes to live largely on an intellectual contact basis rather than on an instinctive one. While the intellectual functions are not necessarily or exclusively, opposed to the instinctive functions, it may be said that intelligence arose in the service of the individual organism and under the domi-
(57) nance of the environment— especially the psycho-social environment— more for the purpose of directing or controlling the instincts than for serving them.
Herrick, after speaking of the relation of the cerebral cortex to the highly elaborated subcortical organic circuits, which it assembles, integrates and dominates, says, "The functions of the cerebral cortex fall into two great groups: (1) Correlations of great complexity, i. e., with many diverse factors. This is of no practical value without capacity for choice between many possible different reactions to the situation. This `switch-board' type of function is simply a higher elaboration of the physiological patterns of the lower correlation centers. (2) Retentiveness of past individual impressions in such form as to permit of subsequent recall and incorporation into new stimulus complexes. This mnemonic function is simply a higher elaboration of primitive protoplasmic `organic memory' or individual modifiability. The mechanism of the first group of functions may be largely innate and heritable; that of the second is necessarily individually acquired. These two functions lie at the basis of all mind." [51] This acquired element, the more original or directive factor in mind, is the result of the impact of the environment.
The pertinent conclusion to the argument of this chapter is that the organism, beginning its phylogenetic existence largely as an inherited structure and organization, has gradually evolved, through the aid of the quality of impressionability inherent in protoplasm, into a highly complex and highly modifiable type. In the higher animals this modifiability is in some degree subject to intelligence, and in man it becomes, in some cases at least, and with respect to some things, rational. Although this consciousness, which is basic to intelligent direction of the organism, arose originally out of the organic neural systems and processes, it has come in the course of
( 58) time to be detached in large measure from its origin, and has fallen predominantly under the direction of the massive and persistent psycho-social environment with its large accumulation of valuations and interests, institutional and otherwise. This psycho-social environment, which has come latterly to control the conscious or directive organization of the higher brain centers, has thereby largely displaced the autonomic and instinctive organization in the control of this same higher brain organization. The psycho-social environment, which probably arose originally as a stabilizer and as an aid to the carrying out of vegetative and reproductive ends, has become in large measure master of the whole organism and shapes its ends subject only to the limitations of inheritance. Thus instinct comes in its manifestations largely to be subjected to environmental control.
