Organic Traits and Their Measurement

Before attempting to view more closely the process of learning, by which this organic system develops still more complex interrelations, it may be well to pause here to answer an insistent question: Under what conditions can the individual organic system be analyzed and measured so as to reveal the organic traits of the person--his physiological strengths and weaknesses, especially the strengths of his drives; his tendencies to excitement and relaxation; his proneness to one rather than another type of physiological integration? Clearly, if we are to answer this question, we need a working conception of traits considered as aspects of the living system, and also a conception of the relations between traits.

From the foregoing it would appear that the observation and measurement of human traits from an organic or biological point of view must involve chiefly the direct observation and measurement of individual tension systems, or indirectly the observation and measurement of their expression. If so, the conception of personality traits from the organic point of view comprises at least three kinds of dispositions, in accordance with the three developmental levels described above.

First, at the level of general undifferentiated response, we may look for the characteristic mode of responses of the tissues, taken collectively. Thus the individual's metabolic rate, though depending partly upon a specific organ, the thyroid, is in some respects a generalized property of his existence even before the thyroid gland appears; it may manifest itself by influencing thresholds for specific response patterns. Since the classification of traits must, so far as is possible, be in terms of their roots, we must first look for the roots in the general dispositions of tissue.

Second, there are traits which depend not globally upon the properties of tissues taken collectively, but upon the properties of specific kinds of tissues; they represent the second, differentiating level of development. Thus the central nervous system, though suffering from no injury, may as a totality be inadequate, whereas the autonomic and peripheral systems are adequate. Or, to use another example, the nerve cells throughout the body may have a long or short latent time or when aroused may exhibit a great or slight lag, compared with corresponding nerve cells in other individuals. Such traits as long warming-up time or extreme perseverative tendency may well express the idiosyncrasy of the nervous system.

Third, traits may arise from a patterned interstimulation of various specific differentiated tissues. Here the trait is traceable not to a specific tissue situation, but only to a mode of interdependence among the tissues. A visceral drive may be an expression not of a single local visceral tension but of a system of tensions, the outer behavior being sometimes an additive, sometimes a much more complex expression of an inner tension system. Similarly, stable or chronic personality dispositions may arise from stable tension systems, unstable dispositions from unstable tension systems. Thus lassitude may conceivably be traceable to a neurocirculatory inadequacy; apprehensiveness, to an endocrine involvement. To be sure, it is hard to imagine such systematic idiosyncrasies without some local source or sources; nevertheless, the trait that actually confronts us arises not from the local but from the patterned situation.

From the organic point of view, personality tendencies of these three types comprise all that the organism is, and all personality traits are included under one or another of these types. There is therefore no special meaning in asking whether the organic point of view is relevant only to extreme but not to normal cases, or to acquired but not to constitutional responses. Organic responses vary from one person to another and from time to time in the same person, and what is extreme from one point of view is the norm for the purposes of some other comparison. If the psychosomatic approach is sound in looking for psychic manifestations of the organic and for organic manifestations of the psychic, there is no sudden transition to a region in which the organic approach becomes "relevant," no point on a distribution curve in which personality may be "practically conceived" to be an organic system. There are indeed all-or-none responses in tissues, and there are all-or-none traits; but if these particular responses do not occur, or these particular traits do not appear, other traits, with their psychosomatic relations, will appear. If extreme hypothyroidism (say a basal metabolic rate of -- 35) "produces" a trait, slight hypothyroidism (say a basal metabolic rate of -- 10) also "produces" a trait.

The confusion on this point, resulting in the widespread belief that "within the normal range" tissue changes are irrelevant to personality, arises largely from the failure to note that the functional significance of a tissue situation in terms of its ultimate effects on behavior may be quite different at different points in a distribution. This is true even with respect to the first and second classes of traits mentioned above. For example, the "degree of overt activity" may be greatest when the tissues are at a certain critical point, so that any increase beyond that point reduces activity, while increase up to that point heightens it. It is even more palpably true of the third class of traits, in which the recognizable trait depends on a network of relations, so that an increase in a local tissue response may either increase, decrease, qualitatively alter, or completely restructure the patterned basis of the trait. All this does not mean that tissues are important only within normal limits; rather, it means that their significance requires intensive empirical research.

And confronted as we are with an organic system which behaves in a certain way because it is so constituted at the time, it does not help us to ask whether the organic point of view is more valid for hereditary conditions, for the after-effects of disease, or for brief "functional disturbances." The organic approach is of course used in different ways, depending on whether the organic situation has been there always (if so, it is usually likely to continue) or only since the time of an injury or disease (if so, the condition and the behavior may be removed), or is a momentary situation (if so, the behavior too, so far as it depends on the specific situation, will be momentary). If the organic situation is there, it will make behavior different. Organic situations change continually in some respects with growth, with tissue modification, with reorganization of inner energies in the learning process; but this does not mean that some situations are organic, others "purely functional" or "purely a matter of habit." Functions and habits, too, are organic events occurring in tissues. Like all other organic events, the function and habit depend both on the dispositions of tissues and on the forces acting upon them.

It must instantly be conceded that this is a schema and a promise, not a completed picture. For purposes of method it is important to insist that personality is a coherent, consistent, organic system, not a scattered group of organs with non-organic cross links between. The concept should become clearer and more valuable as we proceed. Whether a unified view of personality could be achieved without it is doubtful. It is true that many personality dispositions are more easily treated at present by placing the emphasis upon other conceptual tools. When these other tools have had their trial, we shall look back and restate the organic view in such fashion as to indicate the interrelations between the tools in the unified task of personality study.

From the organic standpoint we have, then, to deal with traits as (1) broad characteristics of tissue response; (2) persistent modes of reaction of individual tissues or organs; or (3) persistent modes of interaction between tissues or organs. All three kinds of traits are useful "constructs" in relation to the complex actualities. They are, however, constructs which, like electrons, may serve a conceptual purpose before anyone sees them, or, like zero and infinity, are useful in the absence of any possibility of perceptual verification. On biological grounds, especially the embryological, they appear to be more comparable to the electron than to the mathematical type of construct. For many animal strains and for many human clinical types there are, if not continuous, at least intermittent observations on all three kinds of traits; ratings and experimental behavior observations have already been brought into meaningful relations with all three.

A serviceable example of a trait at the first level is speed of tissue response, as was noted earlier. The general speed of cellular differentiation characterizes not part but all of the growing individual. The question arises: Is there a connection between physiological speed and speed of intellectual response? Evidently there is, for Rounds found a substantial correlation between speed in the DuBois tests and speed in the Achilles tendon reflex. This is not to close a complicated question, but rather to suggest the value of conceiving speed in generic instead of segmental terms. Incidentally, the word "speed" may lead to misunderstanding, for there is little or no connection between this primitive speed attribute and the "congenial pace" of the individual, molded by cultural and subcultural factors and by varying personal motivations. In contrast to generalized speed in this sense must be mentioned various specific speeds, such as speed of walking, or talking, or writing, which are distinctive of the individual; speed in one of these functions is practically independent of speed in others.

Purposivism

The concept of tensions developed here necessarily entails the notion that there exist certain objects in the universe which will raise or lower the tension when contact with them is made. The question therefore arises whether regions of tension are defined teleologically, in terms of a push toward a condition of lowered tension. This question has to do with the "hormic principle," with whether an inner aim, directive, or goal tendency characterizes the life process.

We think that the question usually is phrased wrongly, and we must therefore answer both Yes and No, depending upon what the goal tendency is conceived to be. The tense condition of tissues is a mechanical, electrical, or chemical tension; the tension is not aiming, nor is it aimed at anything. In its essential character, it is like a gas under pressure, like the surface tension of an oil drop, like a charge on a condenser; it involves potential energy. The tension is reduced (kinetic energy taking its place) when contacts are made with certain other objects; hence there is no necessary teleological character in any of the motive processes described here. The hungry infant need not know why be cries, nor the absent-minded, restless man on a warm day know why he starts for the room where the water cooler is; the restlessness is cut short by the bottle or by the cup of cold water.

The question of "directive" may, however, be intended to ask whether, during a period of time, the stresses converge more and more upon a given object, the first infantile whimper being followed by louder yells, and the first twitches by more and more thrashing about, until eventually a more or less unified and specific, imperious demand takes shape. The question of "consciousness of the end" is irrelevant here; the important thing is the impulsive or conative character of the whole movement. Since the various agencies in the body which contribute toward satisfying the needs have their own variable thresholds, it is natural that they should be called out in a fairly regular order. This corresponds to a subjective condition of increasing distress and may eventuate in more and more definite, conscious recognition of what is wanted. In all adult mammals, and in normal twoyear-old children typically, the more obvious needs are accompanied by more and more definite habit systems directed toward the completion of behavior sequences calculated to restore the inner balance, and the subjective state passes from one of struggling distress to one of consciously directed aim. But awareness of the end is not the prime or essential condition for motivation; so far as consciousness is concerned, it is the conative, impulsive aspect that is essential.

If, then, the question about the hormic principle is meant to ask whether motives are passively or actively experienced, whether they are forms of cognition or forms of struggle, the only answer that seems permissible now is one which stresses the fact that there are no static conditions anywhere in the body; that the physical processes themselves are actively readjusting all the time, and consequently that a hormic, i.e., conative, aspect of all activity is imperatively required. Physical tension and sense of struggle are aspects of the same situation. But knowing what one is struggling for Is a late, derived, special experience, in no way essential to the definition.

A related question which to some extent overlaps the preceding question is whether, despite our rejection of mechanism, we have introduced "determinism" or left a place for "spontaneity." This seems to us a completely artificial antithesis. Determinism is a mechanistic concept based upon pushes and pulls, active forces working their will upon blind bits of matter. As far as we can see, there are no such pushes and pulls and, in particular, no isolated pieces of matter to be pushed about; there are only field stresses, forces expressing interrelatedness. There is likewise no capricious, uncaused activity arising out of complete irrelevance, complete indifference, to its context. Spontaneity in the sense of causelessness we cannot use. But we can use it in the sense of a field-structure unity of response, the inner structure utilizing outer forces rather than being at their mercy in responding; in the sense of constant, reemergent adjustment that expresses what one is, as well as the rearrangement of the outer environment; spontaneity which at any moment of the organism's life involves a new organization and a new reaction never completely actualized before. Throughout the discussion we have tried to stress the interrelations between inner stresses and also their relation to outer stimulation of a complex sort; organism and environment are an interacting field.

From the point of view of the nervous system the distinction between outer and inner--that is, outside and inside the skin--means little. The outer stimuli must go through a series of inner transformations before they become capable of activating the nervous system; and when they have done so, they act in company with the inner stimulations reflected in adjoining tissue changes. When climate, for example, is emphasized as an outer environmental stimulus and conceived to alter the personality structure--as when one asserts that the basic attitudes of the exuberant Vedic peoples were subdued upon their arrival in a much warmer region--the picture is oversimplified. It is the enduring effect of climate as a cooperating agency in the living system that is involved; climate may have done this to a specific group, which had a specific personality structure, but it may not be capable of doing it to all men.

A point of view which recognizes that all tissues are motive centers and that all of them constantly interact with the forces of the environment can, moreover, find no place for the distinction between biologically determined and socially determined motives. There is no conceivable way in which during the developmental process a man (or a society) could remain immune to the systematic modification imposed by a given way of living, or remain detached from the cultural standards and pressures which at every moment determine the form and force of the motive pattern. There is no way in which a biological motive could appear in its pristine form in a context of social events. The hunger, the sleep, the love-making, or the power-craving of a man in western society could in no conceivable sense arise from a primitive, gene-determined disposition, the developing structure of which had remained encapsulated, untouched, free from the reciprocity of social living. In the same way there is no conceivable sense in which the craving for activity, for color and tone, for intense experience, for warmth and affection, could be created out of nothing by a system of cultural rules prevalent outside of the newborn individual. There is no way in which "socially derived" drives could be established and implanted like a graft within the body tissues. Culture can alter, mold, or reorganize drives--or rather, it can permit them one form of development or expression rather than another--but it can hardly "create" them out of nothing.

But there appears to be a difficulty here. Can we not, in a thoroughgoing, literal sense, establish in the organism a number of tissue tensions, drives which it never before possessed? On first thought, it must certainly be conceded that the answer is in the affirmative. Drug addiction is a good example. Civilized man has continued to discover new and exciting ways of acting upon his nervous system by chemical means; the new drugs produced in recent years have given him forms of experience which no man ever experienced previously.

The addictions which are thus established may become the most powerful drives within the individual, dwarfing everything else in comparison. (The biochemical nature of such habit-forming drugs is beginning to be understood; it is clear that in respect to some of them, buffer systems within the blood are established which are responsible for the greater and greater dosage required to circumvent them.) In other words, the tissues may be molded not only so as to "want" more of something which they wanted in the first place, but to want things for which there was no previous want. And if it be argued that these drugs fit neatly into some prearranged, limited number of biological potentialities, the reply is that a continuous stream of new drugs is being discovered and that medical men and lawmakers are perennially busy trying to head off the tendency of their fellowmen to make new addictions out of these new discoveries. There may be a limit to the number of drives that can be created, but the limit is not in sight. If this is true in the biochemical sphere, it is certainly even more obviously and cogently clear in the case of social experience, which constantly creates patterns of needs which never existed before.

The single cell is highly structured

The single cell is highly structured. It is structured even in terms of tension gradients; the needs, even of the single cell, are somewhat localized. Growth and differentiation permit, week by week, more and more definite identification of specialized tension regions in the developing body. The degree of specificity exhibited is a function of the embryonic stage, in the strict sense that cellular tissues, transplanted very early, may grow into almost anything depending on their environment, whereas when transplanted at a later embryonic period they lose this plasticity.

It follows that the need pattern of interrelations between specific functional regions becomes geometrically more complex with the increase in need areas. There are more needs, and the dynamic interrelations between them are numerous. This is true not only in the ontogenetic but in the phylogenetic sense. Man has more needs than any other animal, largely because the differentiation process (especially within the nervous system) has proceeded further.

Just as some of the qualities of the bud may be seen in the mature flower, it is important not to think of the achievement of a stage as a renunciation of preceding stages. Thus, for example, the basic tension level of a hyperkinetic system appears in the hyperkinetic qualities of differentiated reflex and of habit. The various components of a habit system share their basic qualities, partly because of communication within the system, partly because the components spring from a common matrix.

But because there is differentiation, there are in the same organism recognizably distinct tension levels; e.g., the acquisition of any skilled act involves progressive concentration of the tension in certain muscles, the reduction of tension in others. The resulting differentiation in tensions is the process which permits their integration in a smoothly flowing activity; the focus of the integration, the figure, shifts in dynamic equilibrium as the act progresses. The figureground relations of such integrated acts are seldom absolutely sharp; there is usually a gradient, a tapering-off of tension from center to fringe. There is thus a region of relatively high tension and an adjacent region of lower tension. We are therefore confronted with the question whether the tension drops gradually as one moves outward from a center, or drops quite suddenly at a given point.

Superficially, the drop in tension seems to be gradual. Finer measurement, however, usually shows that it involves many all-or-none steps. The characteristic mode of the spread of tension from a given region must then involve an all-or-none mechanism. The passage of impulses over the threshold of a receptor cell and the transmission of nerve impulses from one nerve cell to another are of exactly this sort. The excitation of the sympathetic system is a striking case in point; the last little remark "burns up" the patient listener. This may be called a "quantum manifestation"; the body is full of such manifestations.

For most purposes, the spread of tensions may be regarded as diffuse, and the resulting tension at any given region may be stated in terms of position in a gradient. All-or-none regulation of this sort appears in such manifestations as the sudden maturing of locomotor reflexes, the sudden occurrence of salivation in connection with hunger pangs, and the sudden emergence of sex behavior. The principle of summation, as demonstrated by Sherrington, makes clear the possibility of a gradual approach to a critical point at which the response appears. The response is not necessarily proportional to the stimulation; the stimulation must achieve a certain quantum, after which the response then appears full blown.

Such discontinuity will constantly confront us, for it is upon the discontinuity between two or more differing types of integrated action that the possibility of any real organization of personality depends. Since the term "organization" will be used frequently hereafter, a definition of it seems called for at this point, in the light of the case developed thus far. The term organization is used to define the system of interrelations obtaining at a given time between the bodily activities in progress, be these relations spatial, physical, chemical, or what not. The study of organization involves the study of all the dynamic interrelations between processes; and since motives are merely organic processes when looked at from the point of view of degrees of tension, motive structure is simply an abstraction relating to the interrelation of life processes. So far, relations have been viewed at a point in time; often, however, the relational system flows through time. The characteristic cycles, changeabilities, warmings-up, slowings-down, smooth or erratic patterns of change which characterize the individual are as much of the essence of organization as is the system of dispositions at a moment. Briefly, then, organization may be defined as the spatial and temporal interrelations of the life process. This is meant to include specific recognition of the reality of the parts rather than a resort to the principle of holism. At the same time it is meant to stress the interdependence of organism and environment. Since some of the temporal and spatial interrelations frequently shift in all-or-none fashion, we find temporal discontinuities, or quantum shifts, at some points in the organized system; but this never involves a complete collapse of all systematic relationships. And with growth (and experience, too, as we shall try to show), such sudden shifts in organization become less and less conspicuous.

In the general summary of the view developed up to this point, motives are not conceived as levers, nor even as fuel supplies; they are abstractions from an activity continuum, identifiable only grossly in terms of their locus or their formal effects. They are gradients in the sense that tissue situations may be conceived to be centered at certain points and to melt into other tissue situations at a distance. For all that, the gradients are often sufficiently sharp to permit classification in terms of the region and type of tissue situation chiefly involved. The most obvious among them, connected with inner deficits and relations to oxygen, water, and food, may be used as prototypes of visceral motives. The homeostatic or broadly biochemical state is at least an important component of sexual and maternal motivation and of the need for rest and sleep. Activity tendencies in striped and unstriped muscles, reflecting themselves in overt conduct (in stretching, in relaxing, in cramps, in perseverative activity), are cognate with them. Since the phenomena of latency, refractory phase, and hyperexcitability are found in nerve tissue as well as in muscles, and since the muscular and nervous systems are bound in ultimate functional unity, it may be convenient to speak of neuromuscular motivation. This type of motivation differs from the homeostatic or visceral in the sense that homeostatic tension can be most conveniently conceived in terms of instability, especially biochemical instabilities of the blood stream. But the difference is not sharp; the "need" of a tired muscle to relax is doubtless in part biochemical. The biochemical situation acts directly, too, on the nerve cells and muscles, as is familiarly exemplified in the effects of toxins on neural and muscular thresholds and in the unconscious regulation of respiratory movements by the chemistry of the blood. Among the needs of the central nervous system are needs for certain types of stimulation or experience, needs not only for kinesthetic and visceral stimulation, but for stimulation from color, tone, touch, taste, smell. The organism is turned outward; it is gratified by making sensory contact, and it perseverates in, or recurs to such contact. Finally, though the term need must here be used in an extended sense, induced needs are imposed upon the organism by outer forces which upset it; when these needs develop in stress situations they may be called emotions. In any tissue system, and consequently in any motive system, individual differences are manifest in the early months. It is the development, the differentiation, the integration of these individual motive patterns that constitute the first great biological clue to personality.

Emergency Responses

In all the classes of motivation so far considered, we have found the inner tension system prepared, so to speak, to cooperate with outer stimulating conditions; there is a state of readiness. But if we are thrown into a dither by stumbling over a rope or discovering an old letter from an erstwhile loved one, or receiving an unexpected telegram, no "state of readiness" exists. Yet we certainly display "motivation" as we respond. We know no better term to describe this externally aroused state of upheaval than the term "emergency response"; although any term presents difficulties, we shall hope to justify its usage as we develop the story.

From a rough descriptive standpoint motivation may be very crudely divided into two classes of activities, one of which, the "vegetative", serves to maintain the processes of growth, repair, and reproduction, and the other of which (Cannon's "emergency" system) has to do with the mobilization of available resources in a time of direct threat to life itself. Cannon structured the problem very graphically when he assigned the former functions to the parasympathetic (the craniosacral) system, the latter to the sympathetic.

Cannon's original theory of emotions as emergency upheavals certainly needs to be shaken down a bit, but even so it is surprisingly useful; it is worth the work of refining it. The first major point of criticism is that the vegetative responses themselves show all degrees of stressfulness and, when necessary, involve plenty of sympathetic activity. The hungry man's heart may accelerate when dinner nears; the returning lover scarcely shows the retardation of pulse which parasympathetic activity would involve; wild pounding of the heart may appear indiscriminately in a wide variety of conditions, from threat to joyous excitement.

Despite these and more objections, there is still value in the vegetative-emergency antithesis. Though it draws too sharp a line, some sort of line is necessary if any grouping of phenomena is to be achieved. From the present standpoint the term motive may be used very broadly to include all maintenance and extension of life processes, the homeostatic and the continuous motor adjustments to shifting external situations as well as the emergency upheaval states. The term emotion, already used in over fifty senses, may if desired be employed to designate only the emergency responses, notably those of fear and rage. Struggle under pain, suffocation, etc., may be grouped under the fear category if one wishes, and any form of vigorous attack on interfering obstacles may be called rage. Disgust and shame are upheavals due to a threat, too, if the term is stretched. Grief may be regarded as response to an emergency about which nothing can be done. Surprise might be considered a very mild form of startle, and hence of fear. The only purpose of a classification here is to indicate that there is a variety of more or less similar, more or less distinguishable response patterns which overlap physiologically and behaviorally but which, in spite of all difficulties, do constitute a group that no one would confuse with the group of vegetative activities. In general, the distinction lies in the fact that the vegetative activities go on all the time in constant or in cyclical fashion, whereas the emergency group of reactions may appear twenty times a day, or once, or not at all, depending on what happens outside; there may be constant threats or none at all. The patterns are imposed; they are not necessary spontaneous expressions of life. This, like all the distinctions in this field, is too sharp; a man climbing Mt. Everest struggles to breathe just as he struggles to climb. When the inner equilibrium of the neurochemical system becomes slowly more and more unstable as a result of the life processes themselves, and inner behavior leads directly to outer behavior, one may speak of visceral drives; when the inner equilibrium is suddenly or forcibly disturbed by external circumstances, such as threats, one may speak of emergency responses. Mixtures and transitions are obvious. The same is true of summer weather and winter weather, but they have to be distinguished.

In all this we are speaking of the source, the locus and character of the inner imbalance, not the external manifestations. A man may struggle to breathe, or, with bitterness hardened into hate, lie quiet to kill. Consequently the individual differences in all the types of motivation conceived here are individual differences in the inner patterns. These can be studied in three ways: (1) directly through pulse, blood pressure, fluoroscopic examination of the stomach, galvanic skin reflex, measures of finger temperature, etc.; (2) indirectly through inference from external behavior patterns, including the verbal and gestural; (3) still more indirectly through the testimony and inferences of observers regarding their own past and present conduct. The writer's bias in favor of the first of these should be clear by now, and perhaps also his conviction that no physiological indicator means a great deal by itself and that converging lines of indirect evidence, correlated if possible with direct evidence, are a great deal better than any single indicator.

One may wish to retain the term emotion in spite of the lack of agreement in its use, for we can hardly dispense with it when we wish to describe the upheaval of the individual when overpowered by some vigorous external stimulus. Certainly the cerebral cortex is involved, and certainly the lower centers, especially in the thalamic region, are profoundly concerned. Certainly also there is abundant discharge both to striped and to unstriped muscles and to duct and to ductless glands. It would be perfectly proper to regard rage or fear as a visceral drive in the sense defined above, if we wished to stress the internal factors which tend to produce generalized bodily tension, many of which make a person vaguely apprehensive or irritable. When we use the word emotion, however, we usually mean to stress something more explosive, a process by which the individual is catapulted into a new and unplanned relation to his environment, not solely as the result of a tension system which existed before he made contact with the new outer stimulus. Considered in such terms as these, involving both cerebral, visceral, and skeletal adjustment, emotions can be equated with emergency reactions. They exhibit the all-or-none principle more clearly than do the other drives, and as a rule have

rather clearly definable thresholds which differ sharply from one person to another and from one occasion to another for the same person. Constitutional factors again may be inferred from the data suggested above, at least in reference to fear and rage.

Since, however, we are dealing with elementary reactions abstracted from the total, it is proper to emphasize that there is no sharp distinction between the different emotions; they overlap too much. Nor is there a sharp distinction between emotions and other motives, because there is always some "new outer stimulus" and some "readjustment" to be made. By and large, disgust and shame have more in common with fear and rage than they have with the other groups of responses, if we happen to see fit to stress the suddenness of upheaval and the complexity of response. In all four classes of drives (visceral, activity, sensory, and emotions)there is a synergy of the central nervous system, the autonomic nervous system, and all the various effector systems. Some of the most joyful experiences, like exhilaration and laughter, draw from such wide bodily resources as to involve, more or less, all of the four classes of motives.

In connection with emotion it needs also to be stressed that one learns how to cope with one's motives, and that one of the most fundamental and central skills of personality is its means of keeping itself out of certain emotion-rousing situations, notably fear and shame. The degree of success is perhaps the chief factor in the security level of the person. Here, and in so many other aspects of psychology, the laboratory has studied the fully aroused response, while the clinic has studied the means used by the individual to avoid making the response. Organically, of course, the two are aspects of one system.

In view of the difficulty of differentiating between the emergency patterns at birth (none has been sharply defined experimentally except the "startle pattern"), two lines of evidence must be offered to justify the conception of fear, rage, surprise, and mirth, and perhaps some other patterns, as recognizably distinct from one another at an advanced maturation level, and from the "visceral drives." Though emotional patterns are not very easily distinguished at birth, they can be differentiated without difficulty at ten months of age; the maturation process involves not an isolated detail, but a complex expressive pattern. The other, likewise a study by Goodenough, indicates, in the case of a girl blind and deaf from birth, that patterns of surprise, anger, joy, and laughter could easily be observed and photographed at ten years of age. It is likely that the mechanism of skeletal-muscle patterning is responsible for this.

Individual differences in such emotional responses among the newborn have been something of a scandal to a psychology chiefly interested in uniformity of response. The startle pattern shows good uniformity of outline from child to child, but varies largely in intensity; and the attempt to study the familiar patterns of "rage," "fear," "love," etc., has in general revealed the fact that stimuli intense enough to pass the threshold of the phlegmatic are positively traumatizing to other people. Some infants begin to smile and laugh much earlier than others; others remain reserved or plaintive month after month. Wherever we look in the world of motivation, we find big differences; the attempt to iron out individuality by going back to the moment of birth is signally unsuccessful.

But however much we emphasize the functional distinctness of the various individual drives and of the various classes of drives, we must keep constantly in mind that the tension system is a system, that tensions spread through the body, that no one region is ever active without arousing others, and that no drive can ever exist in an otherwise undriven body. There are nodal tension centers, interacting systems at all times. The simplest conceivable formulation would be a figure-ground relationship, in which relative activity in one region is the figure, relative inactivity elsewhere the ground. Far more frequently we find ourselves confronted by a system of nodes of varying levels of intensity and with networks or communication systems conveying energy to and from these tension centers, the general activity level of the organism (depending upon age, health, etc.) serving as matrix, and the specific responses to specific outer and inner stimuli serving as crystallization points.

Sensory Drives

Thus far we have taken into account the two main groups of effectors. Under the term visceral we have included the patterns centered in unstriped muscles and glands. Under activity needs we have included the system that involves the central and peripheral nervous systems discharging into the striped muscles. But the story is far from complete. One of the great dangers threatening an adequate personality psychology is the failure to achieve an adequate balance, through neglect of sense perception and other cognitive functions. Personality is as much a way of becoming sensitive as it is a way of reacting upon the environment. It is as much a matter of selecting and using outer energies as it is of focusing activity. The little child spends a large part of his time exploring with his senses, pursuing sights and sounds and touches, often carrying the activity forward for a brief period after the sensory stimulation is gone-the beginnings of exploratory behavior. The sense organs and the brain regions with which they are connected stand ready to act and are healthy only when allowed frequent action.

As we saw above (Chapter 4), there are large individual differences in such receptor functions and in the affective responses linked to them. We must now go further and stress that since such affective differences exist we must, if we are to be consistent, say that sensory needs or sensory drives differentiate individual infants. This is the implication of the marked individual differences which infants show in their responses to taste stimulation. It is also the basis of the work done on sensory toys, such as cold cream, dough, and finger paints, in which great differences in delight are shown by children playing with these various tactual and kinesthetic stimuli. These differences appear extremely early; they are like the sensory drives which differentiate one puppy from another. They appear to remain rather stable for individual children, at least during the period of nursery-school observations. There is a prima-facie case, then, for sensory drives cognate in importance with activity and visceral drives, and there is evidence that from the very beginning the intensity of such needs shows a highly individual character. It should be added that many studies of musical prodigies indicate an extremely early sensitiveness to tone that is quickly elaborated by any opportunities afforded for musical training, producing in a few years results which most people cannot achieve even after laborious efforts throughout the entire growth period.

The neglect of sensory drives has been largely due to the effort to place all the real generators of activity in the viscera. But even in studying the visceral drives one keeps bumping into sensory factors of various types. The most pertinent example here is a study by David Katz, or rather a twin pair of experimental studies. In the first experiment, a group of hens eat all the grain they can hold; they are taken to another room where other hens are eating from a large pile, whereupon they immediately start eating again and consume a great deal. In the second experiment they are fed all they will eat of grain that has been artificially colored red; complete satiation is evident. They are then given some of the same grain colored green, and again they proceed to eat a large quantity. Is it hunger that is satisfied in the first instance? It hardly advances our understanding to say that the first behavior is pure hunger behavior and the second pure sensory stimulation. The hens eat as actively in one case as in the other. Sensory stimulation is a major source of activation of tension levels. In fact, if the term "sensory" is used as it should be--to include all the different sensory impulses, including those from the alimentary canal--it is the only source. Féré understood this when in illustrating the principle of dynamogenesis he showed that any flash of color, any touch, any sound increases the force of the grip upon the dynamometer. In all hunger situations there are external as well as internal stimuli; summation of stimuli is always the rule.

It is likely that the principle of the conditioned response is of some help here; i.e., the hens have been conditioned to eat because they have eaten in situations where they saw other hens eating. But this again does not advance us far, because conditioning is itself a case of the summation of stimuli (the preparatory facilitating phase shows this), and because stimuli to which the hens have not been specifically conditioned--new grain colors and even revolver shots--increase the intensity of many drive patterns. If this is true, there can easily be complete satiation of an activity, yet immediately thereafter a continuation of the activity when there is an increase in the tension level. And this increase may arise either directly from a local agency acting on the tissues primarily involved, or secondarily through raising tensions elsewhere which are communicated to this primary center. Satiation, then, is always relative; or, to speak more accurately, the question is one of the total field situation, in which the internal dynamics and the quality and quantity of external stimulation must be fully considered. The fields stretch out from the tension center and comprise not only other bodily tissues but all the interacting forces observed within the behavior pattern.

The manner of envisaging the whole problem of the sources of motive has never, perhaps, been described so well as by Diamond, who made clear the misunderstanding of the evolutionary theory which led us to put primitive things at the apex, when actually the evolutionary implications tend to indicate that the more complex structures and functions would never have evolved had they not served a new function different from and sometimes dominant over the more primitive ones. Thus he was able to show that needs for intellectual, esthetic, and other individual and social activities may arise, simply and naturally, from the way in which the human nervous system is constructed and from its interrelations with the rest of the body. From this point of view the music of songbirds, the curiosity and playfulness of chipmunks and kittens, the self-decoration of primates find a phylogenetic place, with science, invention, and art as the natural and necessary products of the sheer process by which complicated functions have led into still more and more complicated functions. The Freudian view that redirected, sublimated sex energies are the source of such activities becomes unnecessary and is seen in its historical perspective as another attempt to Darwinize at a time when Darwinism as a system was conceived to mean the direct derivation of complex processes from simpler ones without recognition of any elements of genuine novelty or any expressions of true emergence. Sexual, aggressive, and other energies may indeed lead to indirect rather than direct expression, and they may be combined with other motives; but the more complex behavior patterns of complex organisms are genuinely functions of their complexity, not merely new revelations of the simpler energies. And when once these complex types of response are possible, they tend to become selfperpetuating through the use of a larger and larger share of the energies available to the organism.

Activity Drives

We have found that in studying chemical motivation factors we have perforce moved into the sphere of muscle activity. Here we come face to face with the fact that tensions in the muscles are also, in all these same senses, motivators. Tension of a muscle group lowers thresholds for another contraction (as in the familiar reinforcement of knee jerks by gripping the hands). Muscle tone is constantly changing and causing new activity. Perseveration--the tendency of an activity in progress to continue beyond the period of outer stimulation, like the maddening thought that runs in the head--is a motivator of no mean significance. So, too, are the direct and indirect effects of any keyed-up condition (excitement) or any relaxed condition. Thus the muscles both guide and initiate action. The movements of the newborn are dependent alike on outer, on visceral, and on muscular stimulation.

We have suggested that the homeostatic balance is often destroyed by events which are not behavioral events. Thirst, for example, may result from sheer evaporation on a warm day, and a considerable caloric requirement must be met even when lying still. One might consequently be tempted to think of the organism as striving to maintain a sort of inactivity, remaining at rest except in periods of extreme want. The homeostasis-seeking group of villagers who have just enough energy to crawl from sun to shade; as the sun slowly moves, they supinely accept an hour or two of coolness before they are goaded again. But it would seem more appropriate to note that in terms of the tension systems which control conduct, the deficits and excesses of inner stimulation (the "too much" and the "too little") both function to cause activity. There are always many imbalances, many forms of restlessness going on. The normal condition is not one of successful escape from activity. Trends toward the reduction of activity and toward the increase of activity are always jointly manifest. The clock is always running down but always being wound up. Even when fatigue, starvation, or illness has forced a violently uncomfortable state of repose upon us, most of the bodily activities go on. The work of the body must be done. Muscular inactivity becomes unbearable; there is a compelling need to do something. At the psychological level something to do, something to occupy one's attention, is compellingly experienced. We seek repose, but we also seek activity. Broadly, the effect of all this may be conveniently summarized by saying that there are not only "visceral needs" but also "activity needs."

It may be worth while to look more closely for the reasons for such activity. Even if a given bodily tissue could carry on its life, its processes of nutrition, oxidation, and self-repair, in complete isolation from all other living tissues, it would maintain an activity level from which there would be daily or hourly variations, and it would therefore permit the notion of relative activity, relative passivity. The instant that any such tissue is considered in relation to its fellows, its activity level is seen to control to some degree the activity level of the rest, and in return to be controlled to some degree by them. The activity level is expressed in an active demand--in the sense of a great readiness to receive--for oxygen, minerals, salts, and a large and complex variety of biochemical agents such as the hormones. All tissues are in this sense active, not only competing with their fellows for a limited supply of needed substances but qualitatively directing the activity and development of other tissues. The student of embryology has long known that one tissue may "rob" another, and the student of muscular exercise has noted the same principle.

But we must go further and stress the qualitative effects which the activity of one tissue has upon the activity of another. We are dealing not simply with robbing, but with the disturbance of the balances required by other tissues, and we are concerned not only with "stimulation" but with organizing capacities. The endocrine glands, for example, act not merely to make other tissues do certain things, but to accelerate some of their many activities in such fashion as to alter the chemical balance and the physiological attributes of other tissues. From this point of view, it will not be sufficient to follow the trail from a deficit in a given region to a visible motor response. It will be necessary to consider the inner shifts which precede or parallel the externally manifested motor pattern. It is not enough to emphasize the system of muscular tensions, for we have learned more and more that the cerebrospinal axis and the peripheral nervous system, the autonomic system and the endocrines, are all parts of one great system mediating the adjustment process; there can be no chemical reaction without its effects on tension in muscle, or tension in the cerebrospinal system.

The term tension is intended literally; the concentration of potential energy under life conditions permits tension reduction. So considered, tension is also characteristic of the nervous system itself. Electrochemical activity goes on constantly in the brain (page 88); the brain cannot stand still any more than the muscles. The brain is no mere telephone switchboard; it is part of the powerhouse. There are, in a literal sense, centrally initiated motive patterns. The nervous system does not wait to be "stimulated"; it is active even under general anesthesia. Activity needs include both striped-muscle factors and cortical factors, factors involving the use of the cerebral equipment.

Although we cannot evaluate the relative intensity of these various kinds of needs, there is one hint that may suggest how subtle the needs of the central nervous system may be. It might be convenient to list the strength, the urgency, the intransigeance of the various tissues in terms of their capacity to force changes in tissues and in external behavior. In view of the current fashion of tracing motives solely to the viscera, it is rather striking from this point of view that although the viscera stand higher in the scale than do the bony and the cartilaginous parts, they are somewhat lower than the muscles and skin, and much lower than the nerve cells. The nerve cells cannot tolerate much by way of toxic effects; the blood is full of buffers which work perpetually for their protection. They can tolerate hardly any water or food shortage; delirium and incoordination appear long before the visceral processes are much affected. And they can tolerate enormously less oxygen deprivation than any other tissues. Thus while in prolonged exposure to "oxygen want" the visual disturbances are traceable both to sense-organ difficulties and to difficulties in the nervous elements in the retina, it is the nervous elements that suffer the most. The cortical needs, then, are not only urgent; they are delicately hinged upon the varying condition of the body and subtly modify all its activity patterns. The point is offered merely as one more suggestion of the artificiality of the current attempt to make the mainsprings of human motivation reside in the unstriped muscles, the glands, the arterial walls, the gastrointestinal tract, or any other visceral structures. These are all of importance, but they are not the only important ones; it would indeed be hard to justify designating them as the most important of all.

The activity needs, probably traceable to tensions both in the nervous system and in the striped and unstriped muscles acting jointly, dominate a large share of the small child's waking hours. Infants may kick when hungry, thirsty, or cold, but they also do a good deal of kicking and rolling, a good deal of wriggling and smiling, when not in any manifest state of visceral need. The little child keeps himself active, knows nothing worse than to have to keep still, just as the adult begins to feel below par when activity is allowed to fall to too low a level. If there is a need to eat, there is in exactly the same sense a need to use all of one's physical machinery. Under the activity needs we should of course include the need to relax and to sleep. And we should also include activity cycles, up-and-down swings of the type to which the term "rhythmic" is applied, and symmetrical or balanced activities, such as those involved in the maintenance of posture and in locomotion. There is a physiological continuum from the sheer inability to sit perfectly still to those compelling needs of activity and creativeness to which progressive education gives so much attention.

Activity needs show summation as clearly as do visceral needs, many different centers of tension combining to throw us into overt activity. A given tension level results from the summation of many factors, but there is a center of maximal activity, as in the golfer's arms as he drives, the rest of the muscular system playing an abundant supporting part. In turn, activity drives may facilitate visceral drives, or vice versa. The energies of the happy, excited childhappy whether it be birthday ice cream or the expectation of a prize at school--tend to "spill over" into visceral or into striped-muscle expression. As far as is known, any stimulus whatever tends to raise the tension level; tension anywhere spreads to some extent to other regions.

The visceral drives

We have taken our examples from the analysis of the hunger drive, which serves as a sort of model for all the visceral drives, i.e., those which depend directly on varying visceral conditions. Under the visceral drives we may list hunger; thirst; excretory tensions; oxygen deprivation; vasomotor adjustment needs, arising in response to temperature extremes; sexual tension, deriving initially from gonad and other endocrine tensions; maternal tensions, due in some degree to endocrine and lactation tensions. All these drives are of course profoundly socialized, and all show some degree of periodicity in a form related to habit (e.g., the day's eating cycle). All of them can, of course, facilitate one another, the state of tension being greater when two or more are involved; and they may all fuse, the individual being unable to explain the peculiar quality of his feeling.

Just as some puppies are great eaters and others are mere lickers and tasters, so too in man individual differences in the hunger drive are well marked in the opening months of life. It would be absurd to insist that they are constant throughout his lifetime, but they are constant enough to worry doctors and parents. One child eats like a horse, the next like a canary. It is not all a question of metabolism, either; and it is certainly not a simple question of energy requirements. Some love to stuff; others nibble and run back to their games. So far as this is an abiding trait, it participates in structuring the child's world--and the adult's.

The maternal and the sexual call for special comment. In view of the fact that individual differences in maternal interest are usually large among the young females of a species, it would be reasonable to ask whether this holds for mankind. Noting that some of his patients had always been thrilled by babies--had gone out of their way to be "baby-carriage peekers"--while others had had no interest in them, David Levy made a systematic quantitative comparison between lifelong expressions of maternal feeling on the one hand and endocrine data (such as length of menstrual flow) on the other. The positive results strongly suggest a constitutional factor. At the same time the great force of social sentiment regarding motherhood is brought home to the growing girl, its force and its form varying from community to community, from family to family; and it not only reinforces within her the primitive mothering impulses, but brings a wealth of feelings deriving from identification with her feminine role, her eager desire to be a mother and not just a person who is mothered --feelings elaborated from the depths of her being and not just an expression of the narrowly maternal as one might find it in animal societies.

When it comes to the individual elaboration of all the feelings associated with sexuality, not even all of physiology, or of psychoanalysis, or of literature, can do justice to the subtlety of the problem. As if this were not complicated enough, the primitive outgoing responses to other persons, and to animals, to flowers, to sunsets, to a thousand lovely things, may become fused with the erotic (in a form varying with cultural emphasis), so that one has the infinite richness or tenderness of romantic love; or these aesthetic or cosmic cravings may be arbitrarily set in opposition to the erotic, so that one devotes oneself to a "higher," and feels that he must reject a "lower" love. So accustomed are we to this sharp cleavage between complex and overlapping forms of experience that we respond warmly to Bourdillon's words that "The light of the whole world dies when love is done" and to Wilder's suggestion that "love is the meaning of life," though Bourdillon is thinking about the love of man and woman, while this is the one kind of love that Wilder does not allow to fulfill itself.

The meaning of heredity

The meaning of heredity becomes clear, then, as the prenatal environment induces more and more specificity in a growing mass which accepts increasing specificity as it accepts oxygen or water. This increase of specificity involves the gradual freeing of each tissue, step by step, from the intimate interdependence which at first characterizes its relations with other tissues. Inherited dispositions become clearer and clearer as more and more of the particularized make-up of the individual, its way of interacting with the environment, becomes evident. The degree of independence of each tissue from other tissues--the degree to which it carries out its own task without submitting to the control of environing tissues--is largely a question of its maturity, as demonstrated in the work of experimental embryologists. Tissues that are grafted very early in embryonic development, say in the period of gastrulation, take on in rather complete detail not only the functional role but the anatomical form which their position requires. Cells which when left to their own devices in saline solution become skin or hair cells may, when grafted in a region destined to become an eye, become typical cells of the eye structure. Let this transplantation be done a little later, and a considerable number of cells will fail to yield to this environing pressure. If it is attempted later still, none of the cells will thus yield. In the process of achieving maturity, each cell has become more refractory to influences from without, except those it accepts in terms of its own basic rhythm. If belly ectoderm from the newt is grafted over the head region of the young axolotl early enough, it takes on the form of the little rods or "balancers" which, in newt organization, characterize the head surfaces, despite the fact that the axolotl itself develops no such head decorations. "The cells have reacted to the lateral head field of the axolotl to the best of their newt knowledge, according to which a balancer is the proper thing to form on the side of the head." Within certain limits, a cell, if young enough, does what the environment tells it to do. There is, perhaps, no more universal generalization about organismic development than the generalization that the younger the organism, the less specific its identity, the more plastic its modalities.

All this illustrates the gradual transformation of any tissue or tissue system into something else; at no point is anything ever "added" to the organism; no "acquired" traits are affixed to it. The genes establish inexorable limits, but what will be done with their potential depends on growth circumstances. Environing pressures do what they can do because tissue potentialities await them; the latter, however, are nothing but potentialities, have no clear destiny of their own. There are many things which a given tissue cannot become, but there is no one thing which it is inexorably destined to become.

It must be noted in the comparisons just made that individual differences still remain within each of the contrasting groups. We never find ourselves obliterating these differences or reducing all humanity to a common pulp. There is a profound response to changed environing conditions--by and large, the earlier the influence the more profound its effects--but we never find infinite plasticity, the complete emptying of individuality into the great sink of a cosmic process. The developmental process that underlies all organismic structuring is a process within specific individual tissues which can be molded into superficially identical forms, but only with varying degrees of reluctance. Traits display varying degrees of modifiability, depending partly upon which traits are involved, partly upon the severity of the environmental pressure, and partly upon the life period during which the pressure is applied. There is always individuality, even in the most extreme environmental pressure, just as there is always a basic humanity appearing through all the individualization which human stuff possesses, in whatever cultural arrangements men may contrive.

These individual differences call at times for a statistical evaluation in which it is legitimate and important to separate (for purposes of abstraction) the contributions of nature and nurture. There is a large difference between the method most suitable for approaching the individual and the method most suitable for reaching a quantitative generalization about the roles of nature and nurture in a given population. It is true that in every individual case nature-nurture is a single indivisible whole; if we describe an individual, making no comparison with other individuals but simply following the chromosome pattern and the embryonic growth, there is nothing hereditary in the organism, and nothing attributable to environment. Since, however, many creatures come from the same stock--indeed, identical twins come from the same germ cell--there is an advantage in abstracting from the field the aspect which we may call genetic similarity. Similarly, since many organism of different stock may be exposed to essentially the same temperatures, pressures, or hydrogen-ion concentrations, we may abstract from many life histories the aspect of environmental uniformity. We may then suitably set up statistical evaluations of the concrete effects of allowing the stock to vary to such and such a degree in any given case, or allowing the environment to vary to such and such a degree. We may say, for example, that with a given group of cases the stock variations produce offspring which in a given environment differ from one another in length by so many inches. Or we may say that members of the same stock (within specified limits) who are subjected to such and such widely varying temperatures have such and such variations in length of body.

No such statistical statement is ever a quantitative generalization regarding the relative importance of nature and nurture. There is no such thing as a trait that is primarily hereditary or a trait that is primarily environmental; every trait is completely and absolutely a hereditary tendency brought to its fulfillment by a specific environmental pressure. But the variability from person to person in respect to each trait within any sample of people under any sample of conditions can always be treated with respect to the question: How is the variability of individuals related to the variability of stock and of environment? Some stocks are empirically widely variable; others, especially as a result of inbreeding, are relatively invariable. When subjected to roughly uniform environmental forces, there are inevitably wider individual differences in the former than in the latter; and though in the case of the isolated individual we need apply no statistics, we may appropriately attribute the wide variability of the observed members of the first group to the stock variability. In the same way, two roughly equated samples from the same stock may be exposed to two environments, the first narrow, rigid, and homogeneous, the second wide, flexible, and heterogeneous. The observed members of the second group will display a variability in accordance with the range of environmental excitations. Combining the two principles, whenever we have known and measurable variabilities of stock and known and measurable variabilities in environmental pressures, we can calculate the approximate relative contributions made by the two types of factors to the observed variability of developing individuals. For our purposes--namely, the discussion of individual personality with relatively little statistical generalization--the concept of the unity of the specific individual nature-nurture field is as important as the question of degrees of dependence upon stock variation or upon environment variation.

Since this is so, and since the heredity of the individual is a constant, whereas the environment is a variable, our task includes the study of individual continuity through the growth process, showing the ways in which the primordial potentialities of the individual develop as a result of the interaction of the potentials with a constantly changing and expanding environing field. At every point in the expansion of the individual, new hereditary potentialities arise; but at every point in this expansion, what is realized in action is not heredity alone but the field relationships which potentialities exhibit when liberated and focused by the specific requirements of the world.

The mechanism of heredity

In all the many-celled forms of life, some cells have achieved specialized functions which involve the loss of their primitive capacity to yield new life forms; the task of carrying on the stock is the property of a restricted group of cells, the germ cells. Body cells and germ cells are distinct. The germ cells are nourished and protected, but, so far as is known, not greatly influenced by the vicissitudes affecting the life of the body. They are capable of transmitting the ancestral traits from generation to generation regardless of crafts acquired, languages spoken, prejudices cultivated by the people who carry them.

Germ cells, however, play their role in the changing, as well as in the continuing, of life. Preparatory to the reproduction process, in which a germ from the father and a germ from the mother unite, each germ cell has undergone a process which throws out half of its germinal potentialities. This "reduction division" yields two gametes, each of which has half the number of chromosomes which the germ cell had before; thus, in man, there are 24 instead of 48. When the fusion of male and female germ cells occurs, the original number, 48, is reconstituted by sheer addition. This process means, however, that of the total 96 available chromosomes in the two parents, there can never actually be more than 48 in the new individual; and which ones they are, so long as there are 24 from each parent, is determined by such infinite biochemical complexities that we have to treat them as occurring at random. Two children with the same parents may be very much alike or they may be very different indeed, depending on similarity or difference in the germinal constitution which they have received; the striking difference between two such children thus occurs not in spite of heredity but because of it. Around a common core of biological similarities in any stock there are the endless individualities traceable to unique combinations of genes. (New genes--mutations-also appear; although they are studied in the fruit fly as soon as they appear, their role in man is practically unknown.)

Another problem relating to gene structure that has taken on importance recently is the likelihood that groups of genes located on the same chromosome, linked together and remaining linked through the formation of the new individual, may be traceable in the individual constitution. Burks succeeded in identifying, through life history data and direct clinical examination, the linkage of certain hair colors with certain tooth conditions such that the members of a family who have this hair color have the same peculiar tooth structure. With techniques established through these somatic studies, she laid a foundation for investigating the linkage of psychological peculiarities with physical peculiarities. The incidence of the manic-depressive psychosis, she suspected, may in some families be linked with identifiable idiosyncrasies of the teeth. As always in such studies, one abstracts a relation from a maze of particulars. Patient care and mental hygiene may help the person with a germinal weakness, just as dental care and orthodontia can. But the importance of such linkage lies not in the fact that anomalies become more controllable, but in the great likelihood that functional unities, genuine elements in personality structure will be revealed. Whatever clings consistently together with a somatic trait, or stems from a common origin with it, has a chance of being "elemental." Since distinct personality features are scarcely likely to be the direct results of such characteristics as nonerupted teeth, and since, nevertheless, the two characteristics cling together from one generation to the next, it is likely that the specified psychological trait has a simple genetic structure. Again we say that this structure is ultimately a biochemical disposition; it is realized only in the process of growth and interaction with the environment; and if it is pathological, therapy may remove it. The fact that a man shaves, although making the face as smooth as one pleases, does not affect the situation confronting one's adolescent sons; the germinal dispositions go on generation after generation.

Of all the verbal quagmires into which man has fallen in his attempt to tell what he is, none has caused more damage than the uncritical use of the opposing terms "heredity" and "environment." Our folklore is saturated with the belief that we inherit certain full-fledged traits and that we acquire other traits by virtue of environmental forces. For three-quarters of a century the literature on "nature and nurture" seemed to support such a belief, and authorities are still quoted to show that some traits are truly hereditary, others truly acquired. The toughness of this form of thinking, its resistance to evidence, is shown by the fact that modern geneticists, embryologists, comparative psychologists, and students of the infant and small child, though perfectly aware of the fallacies in this type of language, find themselves forced, if they are to make contact with their readers or hearers, to employ these question-begging terms.

But if the organism is a tissue system undergoing changes partly because of its own dynamics, partly because of interaction with the outer world, it is "acquiring" new characteristics all the time, never by accretion but always by modification of what it is. No organism differently constituted could acquire in the same way or acquire the same tendencies. What is acquired is just as completely an expression of the inherited make-up of the organism as it is an expression of the outer forces. Nothing meaningful can be said about our acquisition of tendencies, or about the effects of the environment, except in terms of a specific knowledge of the dispositions of the living system. New tendencies, habits, traits are not acquired, plastered on, or stuck on as one affixes a postage stamp to a letter. The organism grows into new phases of behavior, under one form of pressure or another, as long as life continues. Similarly, to use the term "acquired traits" is to talk redundantly, for all traits are acquired by some kind of reaction with environmental forces. There was a time when any given trait was not there; and if one speaks precisely, no trait that is there will remain long in its present apparent form. As Heraclitus said, no man can step twice into the same river; it is a different man, a different river. The way a man talks, or even his attitude toward himself, basic as it may be, is a function both of past tissue changes and of present environing pressures.

If it is true that nothing is acquired in the popular sense, it is equally true that nothing is inherited. As a result of very complex interactions--each of two cells merging its field dynamics with that of the other cell--a new life system involving its own field relationships is established; in it some features of each of the two earlier life systems are still recognizable, but it has a large number of new dispositions which never existed before in any creature on the face of the earth. Hence even the near-identities between the offspring and the parent are not instances of heredity in the popular sense. Since it is not the bodily characteristics of the parents that are transmitted, but only the germinal dispositions, and since organisms show wide differences from their parents in bodily characteristics, the word heredity refers at best to the continuity of certain dispositions from one generation to the next. Even in this sense, however, the term causes a great deal of trouble because dispositions as such cannot be observed. It is the dispositions as realized, as fulfilled by certain environing circumstances, that we can study. There develops the paradox that heredity is known only by the liberation of the hereditary potentials through specific environmental forces; and what is liberated is as much a function of the environing pressures as it is of the latent or potential dispositions.

In the life process, whether studied in embryology or later, nature is not made up, mosaic fashion, of hereditary and environmental elements. The terms heredity and environment serve no purpose for referring to methods of classifying types of behavior, and they can profoundly damage the whole effort in personality study. What they really denote, if carefully studied, is a dual function; the two always occur together and are separated only for conceptual convenience, as we might, for convenience, define two interacting chemical reagents as if one were the agent and the other the substance acted upon.

Defining the environmental pressures as those observed by the physical sciences in terms of light, temperature, acidity, etc., we shall reserve the term heredity for the dispositions of the organism which allow these physical forces to produce greater or lesser changes in it or to manifest this or that type of qualitative variation in its response pattern. Heredity, then, will be the system of predispositions, throughout the life history of the individual organism, which, when different organisms are compared, is responsible for the varying effects of known environmental pressures. In this sense, a birch tree and a man differ in heredity in that they chronically react differently to sunlight and water; and so far as two human beings in the same sense. chronically (from the germ cell on) react differently to sunlight and water, for example, they are different in heredity. Genes and chromosomes are neither a miniature of the later adult life form nor a prophecy of what it is to be. They are simply keys to potentials for differential responses which will ultimately appear under environmental pressure.

Heredity and Individual Growth

Just as it has been the habit of the Calvinist to accept the Biblical miracles while insisting that the age of miracles has ceased, so it has been the habit of our era to start from evolutionary principles and yet to regard man, just as he is, as the fine fulfillment of a cosmic process, the apex of destiny. The self-containedness and the value of personality are such evident realities that the incompleteness, the indeterminateness, the becomingness of personality have been almost ignored. The potentialities from which personality springs change with each generation.

For at least three types of evolutionary process are going on today. First there are endless recombinations of germinal tendencies through crossings, the disappearance of old types, the creation of new ones. It is easy for the biologist to watch this process in large-scale racial mixture and in the mixture of contrasting stocks within a race. It is only here and there, as in studies of homogamy (the tendency of like to mate with like), that the psychologist has taken hold of the problem. If individual response, individual organization, depend in any degree upon the stuff one is made of, the shuffling and recombination of genes entail the same biological necessity for new chemical and neural results as for new results in skin or bone; new gene groupings mean new personality potentialities.

Second, the differential birth rates are already yielding striking data on selective factors. We have to do not only with reshufflings but with shufflings out and shufflings in, the weakening or disappearance of some strains and the strengthening of others, in accordance both with the ancient laws of survival and with the more salient modern laws of struggle for standards of living, social ascendancy, political power. Such results are almost infinitely complex, and the degree of their significance is necessarily a matter of inference from the biology of the individual rather than a matter of laboratory demonstration. The tragedy of the situation lies not in the hopelessness of the problem but in the vapid propaganda of the racialists, who have proceeded (with no genuine evidence) to identify the problems of human biological individuality with the problems of national or racial ascendancy. This, in an era of progress in the cultural sciences, has resulted in a general disgust, on the part of psychologists, with the biological approaches to individuality; the individual baby has been thrown out with the racialist bath.

Third, the cultural forces themselves redefine the significance of biological traits. The same biological dispositions that result in rage, courage, or persistence at a level of hunting or individual or group combat may, in an industrial society, result in indiscriminate savagery or the butting of one's head against the impersonal wall of a frustrating social institution. The consequence is that the biological selection goes on in different terms today from those in which the traits were originally developed, with the probable result that different kinds of men are tending to appear in different subcultural areas, in different social classes. It is an axiom of the stockbreeder that one generation gives only a starter, an intimation; but in a hundred years the domestic strains of swine, cattle, and poultry have been enormously altered, rendered stronger, hardier, more resistant to disease, different strains being developed for different requirements. Tryon needed only a few generations to get non-overlapping "bright" and "dull" strains of rats (in a maze problem) through inbreeding; Hall needed only a few to get well-defined bold and timid rats.

As always, of course, it is the individual that is selected and bred with another selected individual. But with human genetics we have scarcely made a beginning; we are still forced to use animal analogies. A humanity saddled with the most chauvinistic conceptions of racial or national superiority and a humanity suffering from the conviction that cultural situations may indiscriminately make anything out of any human material have, between them, lost the significance of individual protoplasm. When the individual appears he may be obeyed, believed, worshiped; gut it would be sacrilege to inquire as to his origin.

In the meantime, for our own infinitesimal project this situation has a clear result: since most of the inquiries about the facts of personality have been made in terms of the learning process, we must, whenever we emphasize established principles, place emphasis upon cultural dynamics. But wherever we have biological information we shall use it, and in using information from the social sciences we shall try to relate the data to the biological individuality of the persons involved. For just as there is no biological process which is today. completely independent of the social conditions of life, so there is no social science process except in and between the individual tissues of persons. Human evolution, then, as it goes on, yielding new biotypes, new personal potentialities, not only reflects but in subtle and obscure fashion plays a part in guiding the more dramatic and obvious changes in social forms.

Civilization could be sublime in the manner of Assyrian art, gentle in the manner of kittens' play, but culture would express feline rather than simian needs. What, for example, shall we say about the right of free speech? Watch the simians in the field, forest, or zoo, as they chatter. For the great cats, the right of free speech would yield to the right of personal combat. to this "simian world," chatter is so important that we assemble in vast buildings the collections of canned or bottled chatter which the ages have accumulated. We are speaking now, of course, of very raw impulse. Mankind puts an incredible amount of effort into shaping this mass of impulse into integrated and symbolic activities adapted to fantastically complicated social requirements. Everyone born into this world, however, begins with a set of tissues which goes back far beyond the ice age in their primordial demands, their basic insistences, their raw impressions as to what life is about. To forget the stuff of which man the organism is built may facilitate the construction of ideal patterns --in both senses of the term--but adjustment to these patterns may involve tensions or, often enough, biological contradictions.

This does not in any sense mean that society needs to be more apish, more feral than it is. Rather, the argument is that the highest of which man has dreamed is itself ultimately an expression of the kind of tissues of which he is made up. Indeed, we should go much further. We shall try to show in later chapters that organized society has overlooked much of the gentleness, tenderness, sensitivity, and sympathy which are actually the birthright of simian stock. But our chief concern here is to make sure that attention is given to humankind as a species; for whatever we shall have to say about individuality, the traits which enter into it are derivatives of human biology and continuing human evolution.

Personality is unique

This matter of discontinuity--the distinctiveness of the individual --leads to a final broad philosophical problem that has to be faced, and the sooner the better. As G. W. Allport has eloquently shown, personality is unique. Much of the best work of today is centered in this sound and important principle. So, too, it is clear from biology that every individual is unique; not only every tree, but every leaf. Microscopy and mathematics have demonstrated that every snowflake is unique. Every geological formation, every village street, is unique. The uniqueness seems to the present writer to lie not in the constituents but in the modes of interrelation, the organization of the constituents. It is from this general fact of uniqueness of the particular that science, with its disentangling, measuring, conceptualizing method, has proceeded; from such a method has arisen a science of crystals, a science of botany. Why not a general science of the psychology of personality, that is, a science dealing not only with particulars but with laws of organization, the general principles governing the interrelations of the constituent parts? Such a science would be concerned with organization, with architectonics, exactly as crystallography or botany are; it would be interested not only in the individuality of each human being, but in all the reasons for each individual variation in parts or structures, just as the botanist is interested not only in Mendel's laws or in osmotic pressure, but in the way in which they reflect themselves in endlessly diverse fashion when one complete plant is compared with another. There are laws of an extremely general sort that govern all plants; as we move away from such generalization, we find other, more particular laws governing only certain species; and at the end of such a continuum there are very specific principles that govern only one class of event--say the respiratory process of an aspen leaf at sea-level atmospheric pressure. Such laws are presumably uniformities in nature, but uniformities which sometimes have significance for all life processes in all living things, at other times for some processes in some living things, at still other times for a single event in a single living thing.

There may have been just once in cosmic history a whale like Moby Dick. The response of that leviathan would necessarily be an expression of all the physicochemical laws in their specific application to that special case. So, too, there has been in cosmic history just one Confucius, one Jeanne d'Arc, and one you. But your uniqueness does not exempt you from any of the forms and norms of the generalizing method of science. As end results we are indeed unique; but as evolutionary products, and processes, we all express the same cosmic principles. At least, this is the frame of reference within which the present treatment proceeds.

Physical, spatial, dynamic necessity

Almost all the behavioral complexities with which psychologists must deal are basically features of this principle. The primate stock is not, as such, any better stock in survival terms than were earlier existing forms; but the arboreal environment permitted the expansion of a race which had both the physical ability and the wit. The various succeeding forms of anthropoid apes and of primitive man appear to exemplify the barrel analogy well, in the sense that there was always a place for more wit than was already at hand.

There was also a place for huge individual differences. In all the higher forms, mutation can function not only to initiate new species, but to initiate traits which lead to the diversification of types within the species. This diversification, together with the endless chromosome reshufflings already mentioned, means literally that personality, a very complex, highly individualized, highly organized sort of thing, was demanded by nature--demanded in the sense that there was a gap waiting for it, and that when, as a result of mutation and recombination, steps led more and more toward filling the gap, they were "selected" rather than "eliminated."

The organism does not adapt itself to the environment; the environment adapts the organism to itself. The kind of thing that man is, and the kinds of thing that individual men are, are both products of a "necessity"--a physical, spatial, dynamic necessity which demands the filling of the gap in the same sense that a vacuum demands the air which will fill it.

The barrel analogy is also useful in reinforcing the point which we shall have to make constantly regarding discontinuity. Species are discontinuous; they are forms distinct enough so that two species, when crossed, cannot produce fertile offspring. Mutations introduce discontinuous; and species, when once defined, maintain themselves independently for vast periods of time. Even within species, as we have seen, there are some mutations that produce important discontinuities. There are also the discontinuities which result whenever the middle of a distribution is eliminated in the competition with some similar form of life, leaving only the extremes.

But the concept of discontinuity usually relates not to discontinuity in a single trait measured on a linear scale, but to basic differences in structural organization. A bird with a new type of wings produced by mutation can fly only if the wings are related in a specific way to its size, shape, and weight; what survives is a new interrelation of parts. Even a very primitive type of "personality" or "organismic structure" reveals basic gaps between viable types of organization, on both sides of which stand fundamentally different systems of interrelationship. So far as one man's inheritance includes genes which another man's inheritance lacks, and so far as the structural possibilities associated with different genes are necessarily discontinuous, there are true discontinuities between all men.

Organization a term which will be constantly used in relation to every aspect of personality development

This leads us to a preliminary definition of the term "organization," a term which will be constantly used in relation to every aspect of personality development. Organization involves, first of all, the transmission of energy from one region to another; second, the simultaneous passage of energies in various directions in an interdependent fashion as described above; third, the consequent adjustment of one part to another, the constant regularizing effect of tissues upon one another, of which homeostasis or the maintenance of constancy is one aspect. Finally, organization involves not only interstimulation of parts but response of the separate parts of the whole system to outer stimulating forces.

The structure of life is no mere question of the interdependence of all that lies within the body; it is a question of the balance, the interstimulation which goes on between outer and inner forces. As oxygen comes into the lungs and the organism maintains itself by using it at a certain rate, there is no real problem as to when and where the gas becomes part of the living system. If as the oxygen goes down the respiratory passages it is still technically outside the body, what shall we say about the oxygen which is being carried by the red blood cells, or indeed about the oxygen within the individual cells served by the capillaries? The life process is merely focused in the organism; it involves a field extending beyond the body. Organization embraces the entire organism-environment relation, of which the organism is the nodal point but not the complete functioning system.

One more factor, however, remains to be included when the term organization is used. Not only do the tissue systems maintain their homeostatic balance and swing back to a poised normality after an upset; they also undergo systematic progressive change. Organization, then, applies to the temporal dimension as well as to the spatial. Individual growth is organized not merely in the sense that the parts change in an orderly way; since each part is an aspect of a system, the system as a whole changes according to a unified dynamic. Just as lengthening of shadows on a rugged mountainside involves more than the lengthening of individual lines, the growth of any living form involves a progressive alteration of relations in which, despite all change, fundamental unities remain, and in which, despite all fundamental unities, a progressive alteration occurs in the structure of the system. Thus, for example, a study of human aging in terms of decadeby-decade changes in visual acuity is not a study of changes in the eye alone; it is part of a more comprehensive study in which the relation of visual acuity to total functioning efficiency is seen as an aspect of the basic reorganization of human powers throughout the life span.

The entire evolutionary process appears to depend upon the capacity for maintaining basic stability and integrity within the organic system while adding a new feature which establishes a new direction. Thus mutations--sudden appearance of genes within the germ cell, giving rise to radical new body characteristics--initiate new species structurally and functionally different from their progenitors, and over vast periods of time are responsible for progeny: that might never be classified as descendants of their ancestors were not the fossil remains convincing. The process of successful mutation involves the maintenance of life and of most of the essentials of a given form of organization, while at the same time it suddenly adds a completely new characteristic. Whatever may be attributed to the reshufflings of the chromosomes that are responsible for the endless diversities within a species, it is clear that most of the great steps which nature takes by way of initiating new forms of life occur because, upon a base of extreme stability, amazing diversity in new additions is permitted.

Many of the forms which arise through mutation do not survive as well as their parents; indeed, the mutation may be so maladaptive as to be lethal, and with it the bold experiment ends. Often, however, the mutation gives rise to an organism that fits into a niche in the environment which is not already overcrowded with organisms adapted to it. The niches or holes in the environment--capacity to use types of food not already monopolized or to make use of habitats in air, earth, or water not already preempted--permit the newcomer to find, as it were, a place prepared. It is the environment that determines which trend among the countless mutations can be realized in a new species. Both the intrinsic tendencies of living matter and the invitations given by the environing world of nature determine in what direction life will move.

The organism-environment interactions

The organism-environment interactions are both local and general; often there are several different local interactions, each of which must occur concurrently with the rest, so that the general reaction is a complex integrated whole. This requires that the environmental field itself be capable of several related interactions with the organism, and points to the fact that the reciprocity of outer and inner is itself an organized event. The life process is not simply a series of events within the organism, but a field of events in which inner and outer processes constitute a complex totality. The potentialities of life, as in the spore of a fern, can conveniently be conceived as packed within a particle, but the life process itself is not so narrowly localized. A man's life, too, is not within his body, nor is his personality. Potentialities, yes; if we mean by personality the potentiality of individual achievement or social reaction, they are there. The potentialities also exist in an environment which liberally interacts with the potentialities within the man. The actual event, the personal life history, is an innerouter reciprocity, as is all life; personality as we know it is not within the skin, but coextensive with the individual life process, the sequences of liberated potentialities. We know in fact only an infinitesimal fraction of the potentialities within the skin; their status is indeterminate. The more we can find out, the better. But personality study should not be defined in terms of what lies within the skin until we can describe these potentialities adequately. The life processes which we can observe are rewarding objects of study. It is likely, in fact, that it is chiefly through these that such knowledge as we shall ever have about human potentialities will be achieved.

Biochemical systems or fields need first to be defined at given points in time; but it is of their nature to exhibit a time dimension, just as they exhibit three space dimensions. Fields--distributions of energy in space and time--are forever in flux. The most important thing to know about a field may frequently be its direction of change, a direction which can be understood in terms of its own "orthogenesis" and its relation to still larger fields which make up its context.

There need be nothing vague about the matter of interdependence; the reasons for it are often clear. One type of interdependence is exemplified in the selective affinities of various chemical reagents for one another; for example, in the tendency of toxins manufactured within the body, or introduced into it, to react most intensely with particular groups of cells and to have slight or no effect upon others. just as the histologist's stain picks out certain tissues, so the chemical gradients involve not the haphazard but the selective extension of chemical influences in certain directions rather than in others. The same is true of gradients of muscular tension which spread because of neural communication elements and reach some regions more easily than others. There is, indeed, much evidence to show that part of the synchronization of muscles is biochemical, part neural. In the broadest sense then, communication systems within the organism are lines of transmission of energy, following either anatomical paths such as are provided by nerves, or functional lines defined by selective affinities. Interdependence and intercommunication are questions of directed flow within the organic system. They are, in other words, organized at the very start, in the sense that many types of intercommunication are constantly going on, each tissue being the recipient of many kinds of messages and serving in some degree, as a result of its own metabolism or excitation, to initiate such impulses to many other cells.

Questions about the definition of life, questions

The principle is of such evident importance to personality study that we find writers like Guthrie insisting that action occurs only when there is a threat to this inner stability, and writers like Raup who maintain that life consists essentially of efforts to restore this stability or complacency. Yet in the ebb and flow of life processes there must be as much digression from homeostasis as there is return to it, as much exploration as there is homecoming, as much "extravagance" as there is thrift. In fact, homeostasis is a useful concept not merely in showing the safety-maintaining systems of the body, but in suggesting that against a background of relatively constant factors there are factors which permit wide variability, "trial and error" in the execution of activities in contact with the outer world. Homeostasis means, moreover, more than relative constancy of separate features such as hydrogen-ion concentration or temperature. It appears to be very intimately related to the maintenance of the relative constancy of interrelations, such that variation in one aspect of the balanced living system induces compensating changes in other aspects, thus maintaining the integrity of the system.

But does the system as a system actually have this capacity to resist destruction, to preserve itself intact? Yes; this was classically demonstrated by Wilson's experiment on the tendency of living matter to preserve its form. He reduced a sponge to a pulp, squeezed and rolled it flat, and centrifuged it so that no trace of the creature's original outline remained. He then allowed the material to stand overnight. Slowly and in orderly fashion the material reconstituted itself into the organized sponge which it had been before. It is hardly necessary to refer here to a disembodied life goal or entelechy. The particles themselves demand one another in specific chemical and spatial relations. As far as we know, this maintenance of relations is of the essence of life, and therefore of personality. There are of course limits to the capacity for self-maintenance and self-restoration, but it is worth while to stress that homeostasis is not merely the maintenance of constancy in a single phase of inner existence; it implies the maintenance of the structural wholeness of the living individual.

Considerations such as these have raised in a new way questions about the definition of life, questions that are as old as the difference of opinion between Aristotle and his predecessor Democritus. The trouble with the atomism of Democritus lay not in the atoms themselves but in the neglect to consider those formal and systematic interrelations upon which their effectiveness as atoms depended--the presence, in highly organized matter, of organized patterns which are themselves more enduring than the individual particles which enter into them, just as a vortex (such as a cyclone) may maintain itself though old particles are dropping out and new ones being added constantly. (We are here not raising questions as to the difference between organization in the inorganic and in the organic worlds, but simply noting as an empirical generalization that life cannot be studied at all except in terms of organizational constants of this type, like those that appeared in the sponge or in the wounded man.)

Now if this be granted, the evolutionary significance of a tissue system may be largely independent of the particular particles of matter involved. During long eons of adaptation to different environments, wings may, for example, arise out of different organs, yet functionally achieve the same role. For the surviving organism, the important thing is that the function be performed, not the organs through which it is performed. Tissues will in time appear that permit the function necessary to the species to be carried out. The function is consequently not "explained by" the tissues. The tissues are chronologically and logically "explained by" the functions that must be performed if there is to be a living creature for us to talk about.

This was the point upon which nineteenth-century naïve materialism came to grief. The issue is not whether life involves physical and chemical principles similar to those found elsewhere; this is hardly worth arguing about. The real issue is whether the physical and chemical principles operating in their customary way accidentally produced life and the specific expressions of life under various environments, or whether the functional necessities and continuities of nature were such as to call upon specific chemical reagents and physical forces, pulling them into the ongoing system.

To explain personality from within, i.e., atomistically, step by step in terms of tissue changes, would be like saying that a man is five feet nine because he must fit clothes which are made to that specification. As the clothes are chosen and shaped to the individual, the functions of life (growth, repair, reproduction, and all the complex processes which mediate them) draw "clothing," as it were, from the physical and chemical forces outside, so of course they "fit."

This general principle was of course long ago recognized by evolutionists. They noted, however, an important apparent exception in the form of another principle known as orthogenesis, the tendency of living matter during evolution to move continuously in a given direction (through cumulative mutations, cf. page 29), whether this happens to serve a survival purpose or not. It was noted, for example, that the long canine tooth of the sabre-toothed tiger seemed to be getting too long to be useful. Contemporary paleontologists reject this example, and are skeptical of the general principle of a direction in evolution, aside from the requirements of adaptation. But long time trends, having an environmental origin, e.g., the successive impacts of cosmic rays, and a corresponding internal origin, e.g., the tendencies of some unstable molecules to break up in response to cosmic rays, seem nevertheless to need to be fitted into the picture.

It is quite likely that the tendency to extreme individuality among living tissues expresses one of these orthogenetic principles. Organisms need to vary, of course, if diversity is to exist so as to permit a rapid selection of the most fit. But the variation has admittedly become extreme in many higher forms, to a point where natural packs and flocks fail to maintain a biologically necessary unity of action, large numbers of individuals being unable to follow the modal tendency of the group. And even under conditions of stockbreeding, intended to reduce the variability in certain traits, an endless selective process is required. The tendency toward complexity is then probably an orthogenetic principle inherent in the ultimate biochemistry of life, and such complexity would be expected to give an extravagant degree of individuality, i.e., more variability than natural selection cans for.

Throughout all this discussion the chemical rather than the anatomical aspects of life have been stressed. Still, they have probably not been stressed enough. For a long period, psychology suffered from an emphasis upon the supposed primacy of the anatomical and physiological properties of nerve cells and muscles. The studies of physiologists and zoologists have made clear over the last half century that the existence of life is first of all a chemical fact, that the development of tissues depends first of all upon chemical laws, that recognizable fixed chemical structures appear only when the chemical problems have been solved, and that the structures and their interrelations are basically chemical systems. Nature, of course, ignores our overnice distinction between the physical and the chemical. What is meant is simply that the molecular and chemical processes require concentrated study if the molar physical processes are to be understood.

It is necessary, then, in personality study, to stress the maintenance of a stable complex individual system; this is a homeostatic problem and a broader biochemical problem. Secondarily arises another chemical problem, the interindividual variability in the chemical systems of life and the intra-individual variabilities day by day as the personality process changes. When this chemical context has been well defined, problems of anatomical, physical, behavioral response will yield more readily to analysis.