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.