Instinct: A study in social psychology

Chapter 12: Conditional Development and Delayed Instincts

Luther Lee Bernard

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The old uncritical opinion that our biological inheritance consists of whatever traits we possess at birth is too narrow, from the standpoint both of what we do and of what we do not inherit. The fact of birth is, to the person who knows nothing of embryology and but little of individual development in general, such an impressive fact that it completely overshadows other equally or more important events in the early life of the child, considered from the standpoint of heredity. Before this event the life of the child is for perhaps most minds shrouded in mystery. To the ordinary imagination the existence of the child before birth is very hazy, or it is pictured as occurring in some poetic realm which is connected in religious dreaming with the transmigration of souls or with a life of bliss, children being angels or flowers or other beings before birth, according to the various types of poetic beliefs. All this of course has no relation to what actually occurs in the months before birth. Before the science of embryology developed nothing scientific was known about prenatal life, except a few vague impressions which arose from the disemboweling of pregnant women, Caesarean operations, premature births (which were not at first recognized as such) and the like. Our present knowledge, however, is much mere accurate and detailed. Feldman says that the child has already undergone by far the greater part of its development before its birth, "For whilst from the moment of birth till adult age the child increases only twenty-fold in weight and

(269) about three and a half times in length, the increment in weight from impregnation to birth is no less than gob million-fold, and its increase in length is 2,500-fold." [1] After the birth of the child all obvious changes are easily observed and a fairly dependable general account of this period of development grows up in the minds of observers.

A closer observation of environmental factors and of the methods by which they operate and also a critical analysis of the methods of heredity, such as has been undertaken by Mendel and Weismann and their successors, have taught us that the life history of human traits is much more complex than men had formerly been accustomed to regard it, or than many biologists apparently still consider it. It is, therefore, obvious that we cannot now hold to the old dictum that all traits appearing at birth are inherited. Both prenatal and preconceptual environmental influences have had their share in producing the character of the child up to this point.

Equally true is it that not all of the inheritance of the child appears at the time of the birth of the child, at least not all such traits appear on the surface at that time. All his hereditary traits have been fixed by that time; in fact they were fixed at the time of fertilization. The popular mind, which did not think in terms of Mendelism, was until very recently prone to regard the accumulation of inherited traits as going on throughout the prenatal period. The process of receiving inherited traits was looked upon as some vague method of absorbing from the mother (and father) the parental traits. Darwin somewhat systematized this theory of absorption of traits in his theory of pangenesis. The first great and decisive, Now to the absorption theory vane when Weismann put forward his hypothesis of the uncontaminated germ

(270) plasm as the source of inherited characteristics. The death blow was finally dealt to it when the theory of the transmission of inheritance by unit characters through the chromosomes was advanced by Mendel and confirmed by other investigators. But the theory of Mendel has been in the current of biological literature only since about > 900, and while all the recent books on heredity and eugenics give an explanation of it, in some part of the work at least, by no means all of those writers employing biological data have yet applied its principles to the reconstruction of their own theories. The result is that there is often a radical contradiction between different parts of their work,[2] as well as between their accepted theory of method and their practice of methods.

While no hereditary traits are received after the point of fertilization not all inherited traits become manifest externally by the time of birth or even for some years afterwards. This fact of the delayed development of inherited or instinctive traits is sometimes mistakenly spoken of as "delayed inheritance," though our previous analysis has shown that such delay in inheritance is not possible. While the causes of such delayed appearance of instinctive traits are frequently obscured, the fact itself is entirely conceivable and demonstrable.[3] The development of animal tissues and organs seems to be more or less conditional. One phase of growth appears only when some other precondition of growth has been con-

(271) -summated. This is true not only of traits or characteristics which are of hereditary origin but also of those which are the result of environmental pressures. In connection with environmentally induced characteristics, the individual does not write books before he has learned the use of language, nor can he engage in sports before he has developed coördination of simple movements of his extremities through the elementary processes of sensory-motor localization. In a much more specific and definite way is the appearance of the inherited structures conditioned upon the previous appearance of other inherited structures which develop earlier in the series. Thus the eyes do not appear in the embryo until certain nervous structures have reached a particular point of development and the initial coat of hair, the lanugo, comes and goes as the result of certain internal changes characteristic of the embryo. The thymus gland appears before birth and is absorbed in infancy or childhood, having performed the functions for which its secretions are necessary in the developmental process. If it appears or persists at a later stage m the developmental process it is likely to prove troublesome because of the disarrangement of vital functioning and development which it causes.

Apparently much or most of this conditional development or completion of inherited traits in the structure of the organism is governed by the internal secretions, especially those of the thymus, thyroid, pituitary, adrenal, as well as those of other, and minor, glands.[4] The phenomena of giantism

( 272) and dwarfism and of disturbed nervous conditions may be cited as examples in this connection.

Furthermore, it should be noted that the child at the time of birth differs very greatly from his appearance at twenty or twenty-five years of age. The most marked difference perhaps is in stature, for at the former period he is on the average only two-sevenths as tall as he is at the latter date. Also in the matter of proportion of parts of the body to height he differs greatly between those two age periods.[5] These differences in proportion are apparently largely matters of heredity, though not entirely so, because nurture conditions such matters to no inconsiderable extent. The voice also differs radically between the time of birth and maturity and not merely because of use. General organic appearance and functioning likewise show marked changes. For example, the digestive organs are adapted to different types of food at the different developmental periods. The surface structures of the body expand and harden, the face for example growing broader and more definitely marked, the nose especially becoming more prominent. Hair begins to grow on the face of the male of certain races and on other parts of the body of both sexes at about the time of reaching sexual maturity. These and many other physical changes take place apparently in large degree on the basis of inherited traits which are disclosed or brought visibly into the structure under the influence of secretions or other stimuli which appear to function at well-defined stages of development. That the matter of external environmental pressures has much to do with bringing out some of these traits at certain times cannot be doubted, and it is difficult to distinguish definitely between those structures which are due to heredity and to environment: It is not certain to what extent the deeper pigmentation of

( 273) the hair which comes with approach toward maturity is due to conditional development of inherited traits and to the indirect influence of light or to the increased activity of some internal secretion stimulated by environmental factors. In certain races the hair is very dark from the time of birth, though there is some darkening of pigmentation with increasing maturity in all races. Likewise it cannot be said definitely to what extent the change of the soft baby face into the hard well-marked and emphasized features of the adult is due to the strain of the environment working directly and indirectly upon the maturing individual and to what extent to inheritance. It is certain, however, that facial expression is not to be accounted for exclusively on the basis of either heredity or environment.

Generally speaking, then, we may say, that at least four general types of organic conditions, with an almost infinite number of special details, affect the development of the organism. First, in the reproductive cells and the cells resulting from the fertilization of the ovum by the male reproductive cell, injuries [6] to the egg, the position of the cell [7] and the surface tension,[8] all condition development. Second, the presence of infections, toxins, chemical reagents, temperature and nutritional conditions in the preconceptual and prenatal environments of the embryo or foetus, as well as in the postnatal stage of development, produces marked effects upon the developmental process.[9] Third, the internal secretions of the ductless glands, which are already well developed and able to perform their functions in the foetal stage,[10] have very decided results upon the growth process, as well as upon the general functions and functioning of the organs and vital organization, including the nervous systems.[11] Finally, in

( 274) certain cases at least, organic structure does not fully develop until nervous connections are made, while in other cases the use of an organ seems to induce the development of neural connections.[12]

Much of this conditioning of development is predetermined in the hereditary organization itself. That is, the development of one organic trait or organ or tissue organization or content, appearing as the result of the inheritance determined in the chromosomes, makes necessary or practically inevitable the development of some other tissue, organ or organization. A number of questions of interpretation arise in this connection. Is it proper to speak of hereditary determination when development is conditioned by an inherited structure, or organ, or by a structure or organ which was itself immediately or remotely determined by a tissue or organ or organization which was hereditarily determined? How can we tell, in the present state of our knowledge, when a particular growth or organization is determined by the genes in the nucleus or merely by antecedent conditions? Is heredity itself anything more than growth and organization determined by these antecedent conditions of growth and organization, even in the reproductive cell and its fertilized product? If this last proposition should prove correct, does the whole process of inheritance finally reduce itself to a more complicated problem of environmental organization? As yet, as important as they are, these questions cannot be answered with full satisfaction. In some of the cases cited above quite clearly the conditioning influence is an extraneous environmental factor. Especially is this likely to be the case under type (a) above, but it may be true in any one of the four types of conditional development mentioned. In other cases the conditioning factor is a by-product, rather than an integral part of the developmental process. In either case it is clear that environ-

( 275) -ment, as well as inheritance, conditions the development of the organism.

Feldman classified the developmental stimuli effective in this developmental process under two general headings, as follows:

1. Physical
    a. Mechanical
    b. Thermal
    c. Electrical
    d. Radiant
    e. Light
    f. Density of medium
    g. Gravity and centrifugal force, etc.

2. Chemical
    a. Substances found in normal development, e. g., oxygen, C02, water, food, internal secretions, etc.
    b. Substances not found in normal development, e. g., salts, acids, alkalis, alcohol, tobacco, toxins, etc.[13]

He continues, " We have seen that, by the elimination of certain of those stimuli which are normally present, animals have been formed in which certain organs or parts of the body are lacking, or are found in abnormal positions. In this way dwarfs, giants, one-eyed monsters, anencephalic or acephalic foetuses, as well as all sorts of double and partial foetuses, have been produced. Indeed, one may make the general statement that all defective or monstrous forms of development are, as a rule, due to alterations of the normal stimuli rather than to defective hereditary factors." [14] This is certainly leaning far toward the environmental interpretation of the growth process, at least in its abnormal aspects. In answer to the question, "What, influence lay environment upon development?" he says, "It is clear that heredity and environment must be considered as complementary factors in

(276) the question of development, since, in the absence of environmental stimuli, not only would the germ cells never be made to fuse, but would fail to develop after fusion had taken place." [15]

If we turn to lower forms of animal life we observe much more striking transformations in structure, adaptation and functioning in the developmental process. For instance, let us quote the following passages from Gamble, one of the careful observers and recorders of animal behavior: "Many starfish, sea-urchins, and brittle-stars develop from the egg into a larva utterly unlike the parent. In place of the firm radiate body sluggishly moving on the solid ground, the larva has a transparent two-sided body drawn out into tentacles and fringed with cilia by which it glides easily through the water, and drinks as it swims. For weeks to come, its life is amongst the sunlit layers of the ocean where it jostles with the hosts of plankton. Such larva lead a double life. They are almost dual animals, for there grows out of their left side a `coelom' . . . which is almost as foreign to the rest of the larva as a parasite. This sac has within its sphere of influence a portion, and a portion only of the larva. Around it the tissues are moulded into the form of the future star of echinus, whilst beyond that modifying influence the larva still pursues its own devices. Presently the star within it acquires a mouth, a nervous system, and locomotor organs, whilst the larva on which it hangs has still its own mouth, its own nervous system, and its own ciliated bands. This organized growth, however, soon exhausts the larva that bore it . . . and the larva is presently depleted of all its material in order to feed the growth that is, as it were, imposed upon itself. The birth of Eve is no stranger a story than is the development of a starfish or sea-urchin out of the left side of a larva."[16] An-

( 277) -other passage affords an equally good illustration of a somewhat different character. The author says, "There are some remarkable parasitic Crustacea and certain of the lower worms which attain two periods of maturity under diverse conditions of bodily development. Early in life and at a stage of development that seems to promise a high grade of organization their growth is arrested and they become males. Then degeneration ensues, the plan of organization is lowered and though growing in bulk they become less and less highly organized and in this state become female." [17]

He continues, "It is an axiom in zoölogy that sessile parents have active young. Consequently the structure of the young stage is adapted to an entirely different life from the one that it will adopt later on. It swims or drifts freely, now nearer the surface, now at a deeper level in order to keep in touch with the oscillations of the minute animal and plant life upon which it feeds. Frequently this food of the young is again different from that of its parents and new means of catching, digesting and absorbing it are required. The result of these adaptations is a creature so different (apart from size) from its parents as to deceive even the elect; and it is only by actually breeding the barnacle, the oyster and the sea-mat, that the connection between their active free-swimming young and the sedentary mother can be realized. Such animals are said to have a larval stage. The organs of the larva: or freeswimming young are not converted directly into those of the adult stage. They are needed for one mode of life and conform thereto, but they are not suitable for the later habits. Hence a more or less violent change is effected and this change is called metamorphosis. Metamorphosis is accompanied by the assumption of adult habits. The active swimmer touches a rock, floating log, or ship's hulk and after fixing itself becomes transformed into a totally diverse sort of

( 278) creature with sedentary habits and little intercourse with the moving world around it. Instead of drawing itself through the water, it now draws water through itself."[18]

These transformations of the lower animal structures taking place in the developmental process seem to be even more obviously conditioned by inherited tendencies or traits than are those earlier noted as characteristic of man. Yet apparently even they are not wholly the product of inheritance in all aspects. In many cases we find new environments producing differences in coloration, size and other structural conformation more immediately than would be possible if these changes had to wait for variation on the basis of natural selection.[19] Yet the fact that certain types of structural changes can be consummated only when certain environmental stimuli or conditions are present, as in the case of a necessary rest or object for attachment for the oyster, in order that it may develop,[20] does not necessarily militate against the hereditary conditioning of such changes. The environmental factor apparently is here merely a supplementary conditioning which enables the hereditary conditioning to operate effectively.

(279) Environmental pressure does operate under such conditions, but it is usually the passive rather than the active or molding factor. In this case the hereditary factors are active primarily and therefore we speak of the resulting structures as being hereditarily determined. Where the environmental factors are the active ones and the hereditary factors are merely or primarily passive or basic, we properly speak of the resulting traits as environmentally produced or acquired.

It must be clear from the foregoing that, while the sum total of hereditary traits is received at the time of the union of the two parent cells, these hereditary traits are constantly unfolding or developing throughout the developmental period of the life of the individual organism. The individual at the point of fertilization is but a single cell and certainly cannot then be spoken of as mature from the standpoint of its unfolded inherited structure. But the rate of unfolding of these inherited traits is not uniform throughout the developmental period. On the contrary this unfolding goes on at a constantly decreasing ratio. Take a single instance, that of growth in weight, which is probably very largely conditioned hereditarily. The following table shows both the observed and calculated weights in ounces of infants: [21]

( 280)

Age of infant in months Weight in ounces Increase each month
Observed Calculated Observed Calculated
0 127 127 —  — 
1 155 156 28 29
2 187 180 32 24
3 206 206 19 26
4 224 230 18 24
5 254 254 30 24
6 270 273 16 19
7 287 288 17 15
8 300 301 13 13
9 311 311 11 10
10 326 319 15 8
11 333 325 7 6
12 330 330 3 5

The same general facts are illustrated by the following figures quoted from His by Feldman, referring to the unborn human embryo.[22]

Months 0 1 2 3 4 5 6 7 8 9 10 at birth
Length in mm 0 7.5 40 84 162 275 352 402 443 472 490


Increment per month in mm 0 7.5 32.5 44 78 113 77 50 41 29 18


As a result of this decreasing ratio of the unfolding of inherited traits, by far the larger part of them have attained a characteristic, though not a final, development before birth. By the end of the seventh week of the prenatal development of the child, or by the time when the foetal period begins, all the organs of the body are already formed, but not fully de-

(281) -veloped. Growth from this time on during the foetal period, that is, until birth, and even afterwards, is "along lines which have already been laid down in the embryonic or organo-genetic period."[23] All of the ductless glands are also formed and are producing their secretions before the point of birth.[24] In fact the child is already functioning, however imperfectly, in most of the organic ways in which he will ever function when he is born. But mentally and in the higher sensory processes, he is not yet in any large measure developed, and in some ways as regards the mental aspect of things he is developed scarcely at all. The infant is practically a spinal animal,[25] or as Paton puts it, "At birth a human being is practically brainless, all the higher functions associated with the cerebral cortical centers being still undeveloped."[26] The child is deaf [26] at birth and his vision is defective and accuracy in its use must be developed through experience.[27] But in other respects, especially as regards the vegetative and reproductive functions the child has his external structure mainly formed. However, he has not yet in most cases developed the neural connections— the main instinctive and habitual structure— for using this external structure and organization. The child is not, of course, structurally mature or complete in any of his outward or surface characteristics at the point of birth,[28] but relatively he has advanced a long way towards that maturity— much further in fact than our disturbed perspective (due to our seeing the child after birth and not before birth) ordinarily leads us to suppose.

(282) The causes of this maturing of characteristics are somewhat under dispute. Some hints for such an explanation may possibly be obtained from a study of the causes of the aging of individuals. Minot [30] maintains that the approach of old age is due to increasing cellular differentiation and specialization, while Metchnikoff [31] contends that it is the result of the increasing activity of phagocytes. We may assume that both of these processes— cellular differentiation and phagocytosis — are largely the result of environmental pressures, at least in the postnatal period of development, and possibly in the prenatal period also. In this way the demands and influences of the environment ultimately destroy the somatic organism which has grown up around the reproductive cells as a conservator and aid to the continuation of the life of the germ plasm,[32] when that organism is no longer necessary to insure the perpetuation of the germ.[33] Unquestionably other factors,

(283) such as the form of the maternal organs and the distribution of the cytoplasm of the parental reproductive cells, and the chromosome content itself, also help to determine the form and composition, as well as the functioning, of the mature somatic organism which we call the new individual or offspring— the new carrier of the immortal germ plasm.[34]

Whether these processes thus producing maturity and ultimately old age and death are traceable back to inheritance factors or to environmental pressures and conditions we are perhaps not yet able to say. However, it is possible to find partizans of either view. If we state the proposition in another way, we may ask whether if environmental conditions were favorable would we continue to develop indefinitely and never come upon old age and death? This implies, in case of an affirmative answer, that environment is the factor producing maturity of characteristics. On the other hand, it is maintained that the maximum length of life and the behavior of tissues at various developmental stages are fixed in the heredity determining our somatic organization. This may be so, but it is difficult to see from the standpoint of the inheritance of unit characters how such hereditary determination could be accomplished in any direct way. It seems more likely that both heredity and environment play important rôles in the maturing process, the development of hereditary structures conditioning each other and thereby gradually limiting further

( 284) development and bringing the growth and formation of the organism to a standstill within the limits of the symmetry which is implied in or imposed by the inherited structures of the mutually adjusted and restraining tissues and organs, while the environmental pressures finally clog the tissues with foreign matter and stimulate the phagocytes to excessive and destructive activity and thus prevent their normal functioning, and ultimately produce organic dissolution. This statement is, as will be seen, really in large measure a synthesis of the views of Minot and Metchnikoff as applied to our own particular problem.

All of the cases of delayed development which we have so far cited and explained have been of very simple biological structures, such as we might expect easily to be determined in the germ plasm as unit characters and which might readily be determined in the coördinating processes of physical development or growth. But may we not extend this principle of delayed development of hereditarily determined traits to include complex activities and structures which are ordinarily characterized, descriptively in terms of their social significance? In fact, it is difficult to see what justification we can find for speaking of such complexes as the collecting, maternity, reproductive, religious, altruistic, pugnacious, constructive, and numerous other group activities, as instincts on any other ground than that they are delayed developments. They certainly are not developed in the child at the point of fertilization nor at the point of birth. Some of them develop round about puberty or in some other general age period. But no one of them has a fixed point or period of appearance. This fact of variation of the ages at which these several reputed instincts make their appearance in the individual would not in itself be so significant, provided the range of age at which they appear were not too great, for we know that variations in such environmental conditions as temperature, moisture,

( 285) light and fertility cause some degree of variability in the time of the appearance of fruit on a tree or of the metamorphoses of insects. Yet there are limits of time periods beyond which the variability in development cannot go without justly exciting some degree of suspicion with regard to the supposed inherited nature of the resulting phenomena.

A much more significant factor in relation to this question of the hereditary or environmental determination of these organizations of complex activities so often called instincts is the fact that no one of them is definitely and necessarily correlated with any other organic change or process in the individual. The correlation with certain environmental conditions is much more striking and obvious. For example, boys usually learn to fight (or develop the pugnacious "instinct") in the first six or eight years of their lives, or even earlier. But there is no better evidence that there is a definite organic and age correlation here with the development of fighting propensities than that the boys have developed (learned) through the conditioning influences of environmental pressures certain elementary movements which they can carry over with some modification and apply to fighting. That is, fighting may be a complex of acquired activities conditioned by the development of certain elementary constituent or contributory movements and organization instead of an inherited activity process or organization. On the other hand, we find that the chances that a boy will develop the fighting activity depend directly upon the chances he has of coming in contact with environmental conditions which promote fighting. Some boys never develop it, although the preliminary coördinated movements have been previously acquired; for they never have sufficient external occasion to form the habit. Boys who live in a rough social environment and are crowded closely together, where space and the apparatus for play are limited, learn to fight at a very early age,

( 286) while others with well regulated environing or social conditions and without the necessity of competing for the means of play and expression delay fighting much longer or omit it altogether.

Even the reproductive activities, which cannot be successfully performed until puberty is reached, are not definitely correlated with this organic change. Their connection with it is negative rather than positive. Environment has much more than the partial physiological readiness of puberty to do with the development of the typical reproductive acts. Under our fairly closely regulated society many individuals never perform these acts and a larger proportion of the population do not perform them until long after the period of puberty. Others still, receiving the stimulus from a vicious environment, learn to go through practically all of the reproductive acts, except generation, years before puberty has arrived to make the completion of the process possible. In our society the time at which the act occurs depends far more upon the incidences of such environmental factors as marriage, temptation or opportunity, custom, economic condition and the like than upon any physiological condition. And yet many writers speak of this series of acts, which, because of their social significance, we group together and call reproduction, as an instinct. However, no one could or does perform this series of acts without having learned the method, either through imitation or experimentation. Are, then, these acts instances of delayed development of inherited traits or unit characters, or are they instances of acquired traits induced by environmental pressures and, in part at least, constructed out of inherited conditioning organic structure and activity organization and in part out of acquired conditioning neural structure and organization?

To answer this question adequately we must fall back upon the question of fact on the one hand and upon that of logical probability and possibility on the other. This was our resort

( 287) in the preceding chapter. First, as to the question of fact. In the case of reproduction, few if any of the acts of human beings leading up to it are performed in connected series without learning. Yet, unless these acts were so performed it is difficult to see how reproduction could be spoken of as an instinct. It is the complexity of the act as performed by the higher animals, especially man, which makes the hereditary character of the act doubtful, although the hereditary or instinctive nature of many constituent elements or reflexes may be sufficiently demonstrable. Among some of the lower forms the series of acts which eventuate in reproduction seems to be purely tropic. For example the frog spawns in response to a purely biochemical stimulus and, in so far as we know, without consciousness of the relation of his act to the member of the opposite sex who also contributes to the reproductive process. This tropic aspect is also characteristic in part of the human reproductive process, but not wholly, or perhaps even mainly, so. The discharge of semen or the flow of the "libido" and the descent of the ova occur automatically under certain biochemical conditions which are conditioned by hereditary structure. Both male and female respond to certain tactual stimuli in a purely instinctive way also, and various biologists speak of the clasping movement as being instinctive in lower forms.[35] Once conception has taken place the development and delivery of the offspring proceeds on a hereditary basis and would occur if the mother learned nothing regarding the processes involved. Among the human species, as well as the lower animals, certain sex odors, and possibly the sight of primary or secondary sex characters, tend instinctively to draw the two sexes together in a general way once they have developed the technique of locomotion.[36]

(288) But with all these preconditions there is nothing inevitable or automatic about the occurrence of the act of conjugation itself, and much less about the total process of reproduction. All or most of these purely instinctive activities are quite frequently produced in homosexual contacts and in autoerotic activities before they find expression in heterosexual contacts. The final steps and the series of acts which we denominate reproduction are learned, not inherited, just as the abnormal homosexual and autoerotic sexual acts are learned. Reproduction has a large instinctive content. That is to say, a large proportion of instinctive units must enter into the series of acts alongside of the learned units to constitute the completed process which we have learned to state synthetically and abstractly as reproduction. The instinctive units of the series may, and frequently do, occur quite independently of the total process. With the development of contraceptive methods they may occur nominally but not actually in the reproductive process or series, that is, without reproduction, the fact which has given its name to the series of acts supposed to be instinctive. Thus the series of acts known as reproduction is both organized and disorganized under the conscious direction of man.

The question may be asked whether a series of acts so necessary to the maintenance of the race would not presumably be an instinct. Such a question is beside the point of fact and therefore not pertinent. It posits an anthropomorphic and teleological assumption of what is reasonable or "ought" to be, which has no place in science because of the liability of the mind to subjective bias. But since such a method of reasoning apparently has had much to do with predisposing us

( 289) to believe in this and similar reputed instincts, it seems well to answer the question. We may even grant the contention of the defenders of the argument that the instinctive units in the reproductive process were selected into sentient animal life because of their value in promoting reproduction and thus the survival of the race. The answer must be made on another basis, that of the development and function of regulative intelligence in man. Among the lower animals which have not the capacity to acquire or learn complex series of acts, the reproductive process is purely instinctive. In many cases it does not even call for conjugation. Where conjugation is necessary and the process remains instinctive it is sufficiently simple that it can be performed on a tropismatic basis. In man, however, other activity and survival needs have so complicated his structure and changed the position of his body and thrown about it such complex protective coverings in the form of clothes, at once breaking the force of instinctive sex stimuli and hindering instinctive sex responses, as to make conjugation impossible on a purely tropismatic basis. It would not be true to say that other functional needs are of greater importance to the survival of the race than that for reproduction, but it is true that they are of greater importance than the need of purely instinctive reproduction, thus causing man to remain at such a low level of development that reproduction could continue to take place tropismatically. And this is true because man can substitute intelligence and learning as an aid to reproduction to supplant in part the instinctive control of this process. Therefore his structure was altered to meet these other functional needs which arose in the process of evolution and produced an acquired adjustment mechanism and even directive intelligence to supplement and sometimes to supplant instinct in control.

So much space has been given to the analysis of the series

(290) of acts known as reproduction for the purpose of showing that it is not an instinct delayed in its development, because it is one of the best cases which the instinctivists have to support their theory. This series of acts has a larger purely instinctive content (considered as separate units or instincts) than almost any other so— called "instinct" of the complex or socially defined sort. There is therefore a distinct tactical advantage in showing that the activity units in the series which organize the truly instinctive and the learned elements into a coördinated series which results in what we call reproduction are consciously or subconsciously learned or acquired factors. In the case of man at least it is intelligence which transforms the instinctive acts from mere expenditure of energy, however satisfying subjectively they may be, to a position in which they function in race perpetuation. In j the case of man also intelligence is used to devitalize and render sterile, by means of what is popularly known as "birth control," the acts which the instinctivists call reproduction. ; Without this conscious control factor reproduction would not take place, nor without it could the results which nature has provided for in the complete act be frustrated. Hence the process in either case is not an instinct, but an acquired adjustment, though it is more nearly instinctive in the former than in the latter case.

Perhaps the activity complex, also commonly reputed an instinct, which has the next largest content of instinctive units is maternal care— the "maternal instinct." This supposed instinct consists of innumerable acts which relate the mother to the child almost from conception till she ceases to think of it through separation or until death intervenes. The most important organic elements in this activity complex are carrying the child before birth and feeding and cleaning it after birth. All of these are mainly instinctive in their

(291) simple forms, though it is certain that not every child could nurse without the conscious and purposive aid of the mother. Out of these close relationships develops an affective or emotional attitude which permeates the many things the mother does for the child in its postnatal developmental period. Among animals lower than man these three functions constitute almost the whole of the instinctive services of the mother to the offspring. Cleaning it by licking is probably tropismatic. But teaching it to play and to fight,— which some mothers, for example, among dogs and other higher types of animals do— is in the main a learned activity. It would be absurd to suppose that what the human young has to acquire through the learning process could be taught instinctively. The human mother does innumerable things for the offspring, the aggregate apparently having increased with the growth of knowledge and comfort and the limitation of offspring. It needs no argument to prove that the acts of bathing, of modifying milk or of making clothing for the young are not instinctive. The general arguments of the preceding chapters are pertinent here in controverting any such chance assumption. Yet the whole of maternal care is spoken of as an instinct, developing somewhere about puberty, or even earlier as shown by the tendency of girls to play with dolls. Even the lowest savage mother must take thought to care for her child, though much— possibly most— of what she does is instinctive. Among civilized peoples only the barest rudiments or foundations of child care are instinctive acts.

The answer to the supposition that the other activity complexes mentioned in this chapter, and others still which are listed in other chapters, are instincts delayed in development may be found in the discussions of the subsequent chapters dealing with activity complexes miscalled instincts. The learned content in each of these supposed instincts is suffi-

( 292) -ciently obvious to enable the question of fact, as well as that of probability, to be answered with little or no confusion.

We may now turn to the consideration of the questions of probability and possibility in connection with this discussion A true instinct merely delayed in its development may usually be distinguished from an acquired characteristic arising from some particular environmental cause or pressure by observing the method and time of its appearance and the immutability of its character. For example the genuine sex instincts appear at the stage of puberty, which may be hastened or delayed to some extent, by environmental conditions. The nature of these instincts cannot be modified by environmental factors, although the time of appearance to some extent can be so modified. For example, the discharge of semen, the giving of milk to the sucking child, the menstrual processes and the vaginal contractions in orgasm are always typically the same processes, regardless of what the environmental situation is. There is a definite structure determining the functioning of the instinctive act and the limitations of this structure cannot be exceeded. The structure may itself in some cases be modified, and therefore the functioning may be changed, but in such cases both structure and function cease to be purely instinctive. Their end and purpose and form have been modified by forces from without which are unknown to the chromosome content of the reproductive cells. A clearer cut illustration is perhaps to be found in the growth of some plant, as for instance that of maize. No matter what the environment of the maize may be, how poor or fertile the soil, whether humidity is great or small, or what the degree of cultivation is (so long as the environmental conditions mike possible the development of the plant at all) the product will be true to type. That is, the inheritance elements will not be changed. The maize will not be transformed to weeds,

( 293) nor to wheat, nor to some other plant because of environmental conditions or pressures.[37] The plant either remains and becomes maize or does not develop at all. When it flowers, the type of flower is that of maize and when it fruits the resulting grain is the ear of maize. The environment, however, has its proper effect upon the plant. It may hamper its growth even to the extent of preventing its flowering and fruiting, or it may cause the ear to develop into a mere "nubbin." On the other hand, the stalk when grown under proper conditions of moisture, fertility, temperature and light will develop to a good size and produce an ear in which all the grains are filled out to relative completeness. But in all cases the product is maize and nothing but a series of changes in hereditary selection can produce anything else from it. And the same is true of the truly delayed sex instincts such as were specified in this paragraph. They may be modified in minor characteristics of operation such as volume, intensity, frequency, and the like, but they can never be changed in type or kind, if they are truly instinctive.

The above example refers to purely biological characteristics and may be duplicated in many instances. A Jersey cow remains true to type regardless of whether she is fed on clover or corn and her offspring will be Jersey (provided her breed is pure and if she be mated with a Jersey bull). Pureblood negroes produce the same offspring and no sort of environmental manipulation will make them otherwise so far as their biological traits are concerned.[38] On the other hand, social and moral and intellectual traits may be easily modi-

(294) -fied, even be obliterated and replaced, by properly controlling the environmental pressures. The social characteristics of a Booker T. Washington or of a Principal Moton, to select an example of pure negro blood, apparently cannot be distinguished from those of the white man reared in a like environment. Socially, intellectually and morally they classify with Anglo-Saxon rather than with native African civilization, if indeed we may presume to generalize either type of civilization under such broad descriptive captions. Likewise, we have numerous illustrations of the fact that certain environments abound with criminality and other abnormal social and moral conditions. Long ago the social workers discovered that social traits were distributed by communities and economic conditions (power to purchase the normal conditions of living) rather than by race or other hereditary correlations. They found that those sections of cities which housed people of low income, which afforded poor educational and recreational facilities and more especially were provided with inadequate sanitary equipment showed a higher record of mortality, morbidity, immorality, criminality, poverty and the like, than other urban areas. Of course, the extreme instinctivist will reply that such communities are formed largely on a racial or biological basis and he will accordingly attribute these traits to inheritance. But he will find difficulty in explaining why the rates of tuberculosis, criminality, immorality, etc., increase so rapidly for the immigrant who leaves the open country in Europe and takes up his abode in crowded and unsanitary tenements, and why it is so much higher for the native born in the slums than their native-born cousins in the wealthy residence districts. There is a much closer correspondence between the tuberculosis rates for diverse races under the same environmental conditions than for members of the same races under diverse environmental conditions. Where the racial factor remains the same, the social, moral, in-

(295) - tellectual and health characteristics may still change to a remarkable degree. The environment is the variable factor for these people, hence it must be the more immediate cause. Some writers even go so far as to speak of instincts characterizing people religiously, politically, and with regard to the type of sex relations, such as the Russian instinct for Democracy, the instinct for monogamy of the white race, and the religious instinct of the negroes. Yet many people without changing their race, sex or nationality, lose their religious reverence, change their political ideals and even cease to hold allegiance to historic sex attitudes under the pressure of modern city life.

The final test as to the probability or possibility of a social, moral or mental trait being inherited or acquired, we may therefore conclude, lies in connection with the question whether it may be changed in kind in the individual rather than in the group. If the change occurs in the group it may be attributed to selection, based on inheritance, if the period of time which has elapsed since its first appearance has been sufficient to permit of selection. But more frequently the change even here is the result of environmental factors and takes place as a form of social selection. Anyway the content of groups varies so readily that it is difficult to prove sufficient uniformity or continuity of personality to draw valid conclusions, merely from observing the membership, regarding the inherited or acquired nature of their traits. If, however, characteristics which are spoken of as instinctive can be educated into, or out of, an individual, the one trait being replaced by its opposite, this is pretty conclusive evidence that the activity complex was after all environmentally produced or acquired and not inherited. Just this sort of transformation and replacement by opposites is constantly being accomplished. We have built up elaborate systems for the reëducation of a

( 296) maladjusted persons. People are taken out of environments in which they have developed criminality, alcoholism, poverty, immorality, disease, etc., and are transferred to other environments better supervised or artificially controlled and they lose their old social and moral traits and build up new ones; they have their characters literally made over. This makingover process is sometimes so effectively accomplished that the old environments cannot reclaim the transformed individuals to their former characters. In other cases, they tend to revert to their earlier habits whenever they are placed under stimuli characteristic of their earlier lives.

A favorite device of the instinctivists to meet the fact of such an obvious transformation of character and yet to retain the credit of the transformation for heredity is to attribute to the individual two conflicting instincts.[39] Under one set of environmental conditions, one instinct is suppressed and the other operates. Under another set, the opposite balance of instincts is secured. Such an explanation of course gives the determinative or regulative power in society or in individual conduct to environment and thereby the instinctivist becomes an environmentalist. Man remains for him merely a machine with a large number of stop-cocks (instincts). A significant change, however, is produced in the theory of their operation. The simon-pure instinctivist insists that the stop-cocks are manipulated from within, that the instinctive machinery is self-operative and self-determinative. The theory of contradictory instincts, which are suppressed or encouraged by environmental pressures, must, however, admit the assumption that the manipulation is from without. In its ultimate consequences, of course, this means the breaking down of the instinct theory of social control and individual

( 297) character. In this connection we may also raise the question as to whether the opposites are always structural and concrete (biological) or moral and social, that is, synthetic and abstract (environmental), antitheses. As previously pointed out, telling the truth, being religious or patriotic, and their opposites, may quite frequently have the same structure under dissimilar circumstances. In such cases we would have the peculiar situation of opposite instincts being called into play by changes in environment while the heredity (structural content) remained the same. Such a confusion is likely to occur in connection with any of the so-called social or moral instincts, because their definition is in terms of their social values or functions instead of in terms of their structure.

At this point we may supplement our argument on the basis of probability and possibility with an appeal to fact. It is usually within the range of possibility to determine whether these supposed conflicting instincts which may be manipulated by environment really are unit character organizations predetermined in the germ plasm at the point of fertilization or whether they are built up under the influence of new organizations of environmental pressures. The question is really one of how large the instinctive unit is. That the environmental organization or mold makes use of inherited tendencies in building up complex acquired characters or activity structures is obvious enough. The problem is as to how far we may push back our social analysis before we arrive at these original, indivisible, unit-character or inherited elements. The environmentalist maintains that the analysis must be pushed back a great way and that the indivisible elements or units are found to be quite minute when we finally reach them in the process of analysis. The radical instinctivist claims to find that the indivisible or instinctive units are very large and near the surface of social

(298) conduct. If he is correct the variability of social forms and units will be distinctly limited, since acquired activity organizations within the individual are not inherited as instincts. Consequently social progress or evolution will tend to go more in a circle or at least in a spiral whose successive loops remain close together and are of diminishing circumference. If the environmentalist is correct, progress may more nearly approach the straight line curve or at least the sympodial curve emphasized by Lester F. Ward.[40] In view of the fact that the ratio of progress seems to be increasing with the passage of time the decision to be drawn from this indirect argument would seem to be with the environmentalist and to favor the hypothesis of an increasing environmental control.

Furthermore, history has witnessed an increasing degree of individualization or individual differentiation. The savages were very largely of a type, each in the main like his fellows. The whole fabric of social life was mainly homogenous. There was little division of labor or of function. Sex and age were the main dividing lines. Social evolution has been a progression of differentiation of types concommitant with division of labor and function.[41] The ancient sex and age differences tend to be overlaid, though not eliminated, by new cleavages growing out of groupings of individual differentiations. The instinctivist using his highly sophisticated social activity complex criterion of instinct, would have discovered relatively few instincts in the primitive individual, for there would have been manifest but few types of activity or of personality so highly developed. On the basis of the same process of reasoning, modern society must display an inconceivable multiplication of instincts, as evidenced by the great mass of analyzable and dissociable activities we have de-

( 299) -veloped.[42] Yet most of these new types of activities have not appeared in the world until recently. Shall we conclude therefore that instincts are, logically speaking, constantly being hatched anew out of nothing? Or shall we assume that older units of activity, some of them inherited and indivisible, but most of them already complicated combinations of indivisible activity structures or patterns, are constantly being combined and recombined into countless new adaptive organizations of activity in response to the pressures of environment? The latter seems to be the more likely explanation of the genesis of differential individual character and of the highly complex social activity organizations of our day. In the light of such an explanation, most of the cases of reputed delayed inheritance of activity complexes are seen to be merely instances of delayed character development under the control of environment. The delay in character development occurred because it had to await the appearance of certain other aspects or processes in civilization as the indispensable condition to its own organization. The ever-expanding social environment calls constantly for new organizations of the old simple innate or acquired activity units into new character complexes to serve as adjustment mechanisms. These character complexes are not themselves inherited but they are built anew for each individual who needs them for adjustment purposes. They are imposed, so to speak, by his environmental pressures, either physical or social, although his own simpler inborn traits contribute their share to their content.

The argument regarding delayed instincts has so far been directed against the acceptance of the view that the general activity complexes and values, such as reproduction, maternal care (maternal "instinct"), fighting, and the like, should be

( 300) regarded as delayed instincts. They should rather be called delayed habits of action and of thinking, either the one or both. But apparently there are delayed instincts. These are relatively simple inherited, or apparently inherited, stimulus-response processes, which develop their synaptic connections late because the organic preconditions are not earlier present to enable them to develop sooner. Examples of such delayed. instincts are the great group of instincts connected with the functioning of the sex organs and with reproduction and locomotion. The secretion and discharge of the sex fluids, tumescence and detumescence generally, menstruation, the acts or processes of conception, of which there are many, are among the reflexes and chains of reflexes which we may call delayed instincts. The child does not walk or crawl until several months after its birth, and then it makes the necessary neural connections— sometimes rather quickly— which enable it to perform coördinated movements which we call locomotion. It is sometimes difficult to determine whether such delayed neural connections are acquired from environmental pressures or whether they are the result of chromosome determination. Apparently there are elements of both sorts involved.[43] Skill in walking is obviously mainly acquired, but also it seems likely that the suddenness with which certain neural connections which are essential to walking are made indicates that their development is conditioned by inheritance factors. This double source of development is even more patently the case in connection with language. Vocalization has at least some sort of inherited basis, apparently, even if it is nothing more than random expression, similar to random muscular and skeletal motion, proceding or resulting from the processes of

(301) metabolism. But the forms which vocalization takes, especially the elaborate forms which have meaning correlations and which we call language, are acquired. We must speak of habits of locomotion and of language, but these habit organizations evidently contain reflex or instinctive processes which are of great importance in assisting the habits to become formed. And these and many other inherited constituent processes are sometimes delayed in their appearance.

In fact, practically all of the processes which we observe as reflexes or instincts are delayed in their appearance and there is therefore a sense in which all instincts may be said to be delayed instincts. This is because none of the processes which operate visibly in the postnatal period develop at the point of conception. They come one by one as the development of the organism unfolds. The vegetative processes, sense perception, locomotion, reproduction, develop gradually from the early stages of cell division on through the embryonic and the foetal stages before birth and until the maturity of the organism is reached many years after birth. The external body structure for these processes is formed before birth, but its organs and organization do not reach their final form until long after birth. The neural structure or organization which is to control the operation of this external structure in the adjustment process is, however, formed much later. A very large portion of the neural connections are not made until after birth, and this is true especially of the higher control connections in the upper part of the brain. The conscious control connections of the brain are made last of all, the process of making the connections going on throughout life. It has even been estimated that Possibly sumo hundreds of millions of potential neural connections or organizations are never made in the brains of every one.[44] The inference is that

( 302) the organization of the environment has not been such as to call forth these neural connections and the neurones go unused in these relations.

The fact is, therefore, that all activity and thought processes come into organization gradually. All are delayed in organization and operation, but some are delayed more than others. The development of one process is dependent upon the development of antecedent processes within the organism; but it is also, at least in many cases, dependent upon the development of other antecedent processes outside of the organism or in the environment. As yet we are not able to determine with accuracy just what internal processes are dependent upon antecedent internal and what are dependent upon antecedent external processes. But an even greater difficulty is to be found in determining which of these internal antecedent processes are inherited and which ones are acquired. This problem has already been discussed in another connection, where it was shown that we do not yet know what influence this antecedent determination of organic internal processes has upon the question of the relative importance of heredity and environment as social factors. But if we grant that all stimulus-response processes which we cannot prove have acquired elements in them are inherited, thus assuming that at least what we now call reflexes are inherited (and the more definite and unitary of the so-called instincts belong to the same category), there is still a great field of mental processes regarding which there is at least reasonable doubt. We have already disposed of most of the complex mental and the moral and social attitudes and valuations on the ground that they are abstractions. They are either only abstract valuation or descriptive. categories, representing no concrete or consummated overt activity organization whatever, or they are activity complexes with a rapidly shifting content of overt activity, much of which is manifestly acquired.


But there are certain other neural organizations, manifested outwardly or introspectively as attitudes, beliefs, points of view, emotional and intellectual slants, and the like, which it may be claimed are instinctive, although they do not develop until long after conception and birth. If the correlation of these attitudes, which represent inner neural organization, are found to correspond more definitely to typical environmental conditions than to specific age, sex, and possibly metabolic, conditions, the presumption should be against their being instinctive. But even when they appear at approximately uniform periods of age and are closely correlated with sex, thus showing that they are dependent upon inner organic antecedent developments, their instinctive character is not proven. The neurologists have shown us that neural connections of types never before made, because the conscious content or accompaniment had never before existed, are produced, even in the adult brain, by the growing out of neural processes until axones and dendrites meet.[45] In the young child, before and after birth, these extensions of neural processes, building up neural organizations or structure, which makes it possible for the organism to function more accurately in a new adjustment situation, occur very frequently. Also many minor connections between mature axones and completed dendritic processes are being constantly made in great numbers. Apparently the relation of a dendritic "brush" or group of processes to the axone may undergo frequent and marked modifications in a relatively short period of time. These dendritic processes extend and retract themselves like amoebic pseudopodia [46] under the influence of chemical conditions in the brain. What is the relative importance of hereditary and environmental determination in making, breaking and modifying these connections which constitute

(304) the neurological basis of the attitudes or thought, and ultimately of centrally controlled action, it is not now possible to say. But we do know that the part of environment in this connection is very large, in some cases apparently predominant. We know, in fact, that there is a very close correlation between the type of the attitude and the character of the psychosocial environment, especially with regard to ideas, attitudes and beliefs. But what are the biochemical and biophysical mechanisms, by means of which the environment can organize the inner neural structure, we do not yet know.


  1. W. M. Feldman, The Principles of Ante-Natal and Post-Natal Child Physiology, Pure and Applied, 4. See also pp. 122, 252-5.
  2. Such a contradiction has previously been shown in the works of Gamble and Feldman and other writers.
  3. It is possible to hold that traits are not determined in the inheritance at the point of fertilization, but that all future development is the result of environmental conditioning and thus that our traits are mainly or wholly of direct environmental origin. The investigations of the chromosome mechanisms lead contemporary biologists to hold to the contrary view. But if this theory should prove to be correct it would only strengthen the argument of this book. In presenting the criticism of the theory of instinct found in these pages it has been the intention of the author to base his biological arguments on the currently accepted and best attested theories in the science of biology, since this has seemed to be the only sound procedure to follow.
  4. See, for example, H. W. Coshing, The Pituitary Body and Its Disorders; S.W. Bandler, The Endocrines; L. Berman, The Glands Regulating Personality; W. B. Cannon, Bodily Changes in Pain, Hunger, Fear and Rage. These works are not considered to be of equal value, but they are suggestive of aline of investigation which will be pursued more fully and accurately in the future. Even the conventional physiologists and neurologists are taking cognizance of the influence of the ductless glands upon the growth of the organism and its personality, as is shown in passages in Feldman, op. cit., C. J. Herrick, Introduction to Neurology; S. Paton, Human Behavior, etc.
  5. Feldman, op. cit., 120, 146, 148) 157, 169, 178, 180-6, 200 ff., 216-218, 228-9, 250-5, 557-8, 569, 646, etc.
  6. Ibid., 85.
  7. Ibid., 92, 111.
  8. Ibid., 97-8.
  9. Ibid., 111-113.
  10. Ibid., 186-90.
  11. Ibid., 186-90.
  12. Ibid., 591
  13. Op. cit., 110.
  14. Ibid., 110-111. See also p. 7.
  15. Ibid., 110.
  16. F . W. Gamble, The Animal World, 210-11.
  17. Ibid., 176.
  18. Ibid., 176-8. See also p. 174 and chs. 8 and 9.
  19. For examples and citations see previous chapters; also, E. S. Goodrich, Evolution, 36-7; Jordan and Kellogg, Animal Life, 104, 153; Geddes and Thomson, Sex, ch. 4.
  20. This fact is illustrated by the following passage: "Our common hermitcrabs require the shelter of a gasteropod shell and are never found except in such shells. One species, however, is found bearing not only a shell but a shell crowned by an anemone which does not occur elsewhere. Another is encrusted with a sponge which gradually dissolves away the calcareous shell, and this species usually harbours a Nereid worm which is only found in this situation." (Gamble, The Animal World, 166.) Again, "More striking instances of such coalitions are seen in the fish Fierasfer, which hides itself in the large sea-cucumbers or Holothurians of the warm seas; in the coral reef fish and prawn that dive into the interior of large sea-anemones at the approach of an enemy. Even on our own coasts shoals of fry often accompany the larger medusa that drift north and westwards in summer, and at the approach of a shadow or disturbance, snuggle under the protecting disc and lie protected by the stinging tentacles. Certain Crustacea, notably the reddish Hyperia Galba, also associate with the Medusa Aurelia." Gamble, op. cit., 167. See also p.179.
  21. Feldman, op. cit., 251.
  22. Ibid., 252.
  23. Ibid., 7
  24. Ibid., 186.
  25. Ibid., 557-8, 569
  26. Human Behavior, 133.
  27. However the auditory nerve is fully developed at birth. Feldman, op. cit., 619.
  28. Feldman, op. cit., 239, 603-4.
  29. Ibid., 764, 165, 767, 769, 777, 773-4, 778, 180-6,233, 557, 572, 616-17, 633 etc.
  30. C. S. Minot, The Problem of Age, Growth and Death.
  31. The Prolongation of Life.
  32. W. D. Henderson, Biology, 84.
  33. The signs of old age are briefly summarized by Henderson as follows: "With increasing old age we find changes in the body that are usually called atrophy. This atrophy occurs in all the tissues and organs, and is usually accompanied by loss of the cellular tissues and increase in the fibrillar, and also by a decrease in the activity of all the parts. In the old we may note some loss of memory, less readiness in grasping new facts and in pursuing new lines of thought. There is often also a marked tendency to remember old and far-off things, a token of the characteristic loss of the old. If we turn to the facts that an examination of the body reveals we see everywhere this atrophy of the parts, faintly indicated in one organ, more strongly marked in another. Many parts of the skeleton are in youth cartilaginous, but in the old most of these parts are replaced by bone, and though this displacement by bone indicates an advance in structure, physiologically it is far from advantageous, as it represents a loss in elasticity. The change in the structure of the bones themselves may be regarded as an advance in structure, but again it is disadvantageous, as it marks an increase in fragility. In the digestive organs the stomach may be small; the minute glands in the walls arc usually fewer in number and consequently less efficient than in the earlier stages. The muscular layers of the intestinal walls are thinned, and this lessens their peristaltic action. The lungs become stiffened; the walls between the airspaces become thick and hard, and the air capacity of the lungs becomes diminished. The heart is usually enlarged, but its power is impaired, and the pulse-rate is thereby increased. We see also that the germ-cells cease their activity in the very old, and so one of the great functions of life is blotted out entirely from the history of the individual. The whole of the nervous system suffers, and the brain itself shows us without a doubt that after maturity is reached, the shrinkage of the brain begins, and continues steadily to the very end of life. Physiology also shows us that the shuffling gait, the tardy response, the slow speech, the imperfect sight, and the difficult hearing, are but sighs of lessened power in the muscles, of diminished control over the action of these muscles, of inferior coördination, and of nerve decay."
  34. Recently much has been made by some physiologists of the influence of the endocrines upon the form and development of the unborn organism, and later upon tissue decay and death. The chemistry of the endocrines may be assumed to be in some measure susceptible to environmental determination.
  35. See for example, Geddes and Thomson, op. cit., 63.
  36. McDougall thinks that there is an instinctive tendency for the male to be attracted and excited by the secondary sex characters of the female, even to the point of looking for the primary sex organs and thus being attracted by the lower part of the body and pelvic organs of the female. Introduction to Social Psychology, 8th ed., Supplementary ch. 2. I think, however, this attraction of the female parts for the male is mainly or wholly due to his acquired recognition of their relational significance.
  37. Popular traditions and beliefs do impute such changes of kind. Among many farming communities there is still prevalent the belief that wheat will turn to "cheat" or tares when too heavily pastured in the autumn or early spring.
  38. Even if the findings of Boas' studies on change in head shape in the second generation of immigrant stocks and similar studies be accepted they do not alter the truth of this proposition.
  39. Such as, for example, the so-called instincts of self-assertion and self-abasement. Ellwood speaks of instinctive truth telling and instinctive lying, two opposite qualities, though they do not necessarily involve opposing structures. See Sociology in Its Psychological Aspects, 223.
  40. See his Pure Sociology, 71 ff.
  41. See E. Durkheim, De la Division du Travail Social, for discussion of this point.
  42. Such a hypothesis would appear to have the support of current usage as evidenced by the findings set forth in Chap. IX.
  43. There is, of course, also the possibility that such incomplete mechanisms as that of walking represent vestigial instincts— instincts which were organized in the inheritance of the lower animals but which have been disintegrated under the influence of protective maternal care. See discussion below.
  44. M. F. Meyer, The Psychology of the Other One, 140-1.
  45. C. J. Herrick, Introduction to Neurology, 44 ff.
  46. Ibid., 111, for a statement of this view.

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