The Non-intellectual Aspects of Personality

The organism may be regarded as a dynamic system organized about a series of activities necessary for the maintenance of its own existence and that of its species. By virtue of its inherited structure, it possesses corresponding reactive mechanisms which are potentially able to carry out such activities. Motivation deals with such basic mechanisms, their mode of arousal, and their manner of development. Most of the early responses are spontaneous--a term which means simply that the stimulus for the activity comes from some tissue within the organism rather than from without. A "tissue need" sets up streams of nervous impulses which bombard the central nervous system until a mechanism satisfying that need is developed. Thus hunger contractions of the stomach send afferent impulses into the central nervous system until food is eaten. Accumulation of urine or feces distends the bladder or the rectum, which in turn stimulates the central nervous system until micturition or defecation results. The original effect of these constant streams of impulses is to excite random movement. That part of the random pattern which is most appropriate to the need becomes fixed, as well as attached to external stimulus situaThe nonintellectual features of personality are discussed under a wide variety of terms, including extroversion-introversion, sociability, aggressiveness, egotism, nervousness, perseverence, instability, deceitfulness, and dependability. Examination shows that many of these terms cover similar aspects of personality; in fact, due to the absence of more precise knowledge, they can be placed in a single class and taken to refer directly or indirectly to emotional behavior or temperament. Although not truly definitive, our classification serves a present convenience.

Body Structure and Temperament

Many attempts have been made to establish a direct relation between structure of the body and temperament. Physiognomy, phrenology, graphology, and pigmentation (in the eyes and hair and skin) have all undergone searching investigation and have been found wanting. Of course, one might argue that such results show the invalidity of the psychological tests as much as they show the crudity of the structural measures; but however the matter is stated, it is apparent that this approach has been far from fruitful.

If any relation actually does exist between morphological development and temperament, it is probably indirect, with a third factor responsible for both. Thus glandular differences may produce characteristic variation in temperament as well as determine certain features of body structure. Pathology has

shown the curious distortions in both structure and function which accompany the malfunctioning of the thyroid, pituitary, and sex glands. The vascular connection between two embryos in the uterus makes possible the hormonal modification of the structure and personality of one twin by the other. It seems probable that the amount of a specific hormone in the blood is definitely related to the size of the gland responsible for the secretion. An enormous variability in the weights of the endocrine organs of different rabbits, and man is undoubtedly even more variable. Furthermore, while the weight of the brain, heart, and other internal organs is roughly proportional to the total body weight, the endocrine glands show no such constant relations. A small thyroid may thus be forced to coordinate in function with a group of large organs. This obviously will not produce the same effects as when a large thyroid is balanced against a similar organ relationship. So complex is the problem of organ balance and equilibrium that no known mathematical expression can yet indicate all the possibilities of differentiation.

The thin "linear" type and the fat "lateral" type of structural development and believes that these are correlated with both the temperament and organ balance of the animal. It is to be hoped that more quantitative measures of temperament will be utilized in later studies, for only by such means can we expect any exact information. We are entering here upon the highly speculative field of endocrinology, and one guess is about as good as another concerning what the interrelations of gross body structure, temperament, and glands will ultimately turn out to be.