particular action on separate organs, may operate in parts. Also, because antagonisms exist between the middle and either end division of the autonomic, effective states may be classified according to their expression in the middle or an end division and these states would be, like the nerves, antagonistic in character. And finally, since the adrenal glands are innervated by autonomic fibers of the mid-division, and since adrenal secretion stimulates the same activities that are stimulated nervously by this division, it is possible that disturbances in the realm of the sympathetic, although initiated by nervous discharge, are automatically augmented and prolonged through chemical effects of the adrenal secretion. That the adrenal glands are subject to splanchnic influence has been demonstrated anatomically and by the physiological effects of their secretion after artificial stimulation of the splanchnic nerves. Impulses are normally sent along these nerves, in the natural conditions of life, when animals become greatly excited, as in fear and rage and pain. There is every probability therefore, that these glands are stimulated to extra secretion at such times. Both by an exceedingly delicate biological test (intestinal muscle) and by an examination of the glands themselves, clear evidence has been secured that in pain and deep emotion the glands do, in fact, pour out an excess of adrenin into the circulating blood. Here, then, is a remarkable group of phenomena—a pair of glands stimulated to activity in times of strong excitement and by such nerve impulses as themselves, produce at such times profound changes in the viscera; and a secretion given forth into the blood stream by these glands, which is capable of inducing by itself, or of augmenting, the nervous influences which induce the very changes in the viscera which accompany suffering and the major emotions. 10. The Nerves Concerned in Internal Emotional Response [WOODWORTH, R. S., Psychology-A Study of Mental Life, pp. 124–125. New York, Henry Holt & Co., 1921.] There is a part of the nervous system called the "autonomic system," so called because the organs it supplies-heart, blood vessels, stomach, intestines and other internal organs, possess a large degree of "autonomy" or independence. The heart, it will be remembered, beats of itself, even when cut off altogether from any influence of the nerve centers; and the same is true in some measure of the other internal organs. Yet they are subject to the influence of the nerve centers, which reënforce and inhibit their activity. Each internal organ has a double supply of nerves, one nerve acting to reënforce the activity of the organ, and the other to inhibit it; and both the reënforcing and the inhibiting nerves belong to the autonomic system. The autonomic is not separate from the main nervous system, but consists of outgoing axons from centers in the cord and "medulla" (part of the brain stem). It has three divisions, one from the medulla, one from the middle reach of the cord, and one from the lower part of the cord; and these three divisions are related to three different emotional states. The upper division, from the medulla, favors digestion by promoting the flow of gastric juice and the churning movements of the stomach; and at the same time it seems to favor the comfortable, rather lazy state that is appropriate for digestion. The middle division (often called the "sympathetic," though the name is rather misleading to a student of psychology, as it has nothing to do with "sympathy") checks digestion, hastens the heart beat, and stimulates the adrenal glands to rapid secretion, thus giving rise to the organic condition of anger. The lower division has to do with the bladder, rectum, and sex organs, and is active during sex excitement, for one thing. The lower centers in the medulla and cord that give rise to the autonomic nerves are themselves much under the influence of the higher, cerebral centers. Thus appetite for food, and the flow of gastric juice, can be aroused by the sight of good food, or by hearing or reading about food, or even by merely thinking of food; and both anger and sex appetite can be aroused in corresponding ways. We should notice right here the antagonism that exists between the middle division of the autonomic and the other two. Suppose the upper division is active, as in comfortable digestion, when an angering stimulus supervenes; then, as we have seen, digestion halts, the upper autonomic is shunted out of action by the middle division. In the same way, sex appetite is shunted out by anger. QUESTIONS AND PROBLEMS 1. What evidence have we that human nature has a physiological basis? 2. What biology and physiology should the student of education know in order to understand his psychology? What is meant by the neural basis of behavior? 3. Describe the functions of the nervous system (cerebrospinal) in the simplest and most general terms. 4. What are the functions of the autonomic system? 5. How are acts controlled by the three levels of the nervous system similar? How are they different? 6. How would you explain learning in terms of the nervous system? How would you explain thinking physiologically? 7. Contrast the physiologist's localization of brain functions with the phrenological view. 8. How do the glands affect behavior? 9. To what extent will a knowledge of anatomy and physiology of the sense organs enhance an understanding of educational psychology? 10. Is it wise to build a psychology upon a physiology of the nervous system about which we know comparatively little? Can behavior be explained in terms of bodily processes? 11. Does a knowledge of the structure of the nervous system, and its functioning in so far as we know it, give us a complete understanding of mental life? 12. Does a psychology based upon a physiological and biological foundation satisfy you? Why? To what extent, if at all, is your satisfyingness conditioned by your mind-set, such as your particular physiological or philosophical bias? 13. Does an interpretation of behavior in terms of S-R bonds conflict with the basic principles of organized society and judicial law? Why? 14. How might what we have learned from this and the preceding chapter affect our educational practice? 15. "The theory of identification attempts a reconciliation of the purposive and mechanistic concepts. It identifies the inner reality of neural processes with consciousness. Consciousness is the reality and neural processes the mode by which this reality is apprehended by a second organism. Thus, will and purpose, if objectively apprehended through the senses, would necessarily be apprehended as mechanistic, and in terms of reflexes." (Prince) Discuss this attempt at integration and reconciliation of the two, apparently opposing, views. Does the attempt satisfy you? Why? REFERENCES ANGELL, J. R., Introduction to Psychology (New York, Henry Holt & Co., 1918), Chaps. i, iii. BOLTON, F. E., Everyday Psychology for Teachers (New York, Charles Scribner's Sons, 1923), Chap. v. BURT, Cyril, The Young Delinquent (New York, D. Appleton & Co., 1925), Chaps. v, vi, xiii. CHILD, C. M., Physiological Foundations of Behavior (New York, Henry Holt & Co., 1924). CONKLIN, E. G., Heredity and Environment (Princeton, Princeton University Press, 1916). DENDY, Arthur, Biological Foundations of Society (New York, D. Appleton & Co., 1924). DUNLAP, Knight, An Outline of Psycho-biology (Baltimore, Johns Hopkins Press, 1914). HERRICK, C. J., Neurological Foundations of Animal Behavior (New York, Henry Holt & Co., 1924). LASHLEY, Karl, Articles on "Cerebral Function in Learning," as follows: 1. Psycho-biology, Vol. 2 (1920), pp. 55-135. 2. Journal of Comparative Physiology, Vol. 1 (1921), pp. 453-468. 3. Brain, Vol. 44 (1921), pp. 255–286. 4. American Journal of Physiology, Vol. 39 (1922), pp. 44-71. 5. Archives of Neurology and Psychiatry (1924). 6. Psychological Review, Vol. 31 (1924), pp. 369–375. PILLSBURY, W. B., Essentials of Psychology (New York, Macmillan Co., 1920), Chaps. i, iii, iv. WARREN, H. C., Human Psychology (Boston, Houghton Mifflin Co., 1919). WOODRUFF, L. L., Foundations of Biology (New York, Macmillan Co., 1922). CHAPTER IV HEREDITY AND ENVIRONMENT Modern conceptions of heredity have been largely derived from three distinct lines of investigation: First, from the study of embryology in which the biologist concerns himself with the genesis of various parts of the individual, and the mechanism of the germs conveying the actual materials from which these parts spring; second, through experimental breeding of plants and animals; and third, through the statistical treatment of measurements of a large number of parents and offspring to determine the extent of resemblance of parents and children in each particular respect. We must discriminate sharply between the inheritance of a predisposition and the inheritance of a disease itself. What we really inherit is a constitutional susceptibility to a peculiar germ. There is no doubt that certain families are more easily infected than others, and much less resistant to the ravages of disease when once it gains a foothold. We should avoid confusing conditions which may have entirely different sources of origin. A few germ diseases like syphilis, though not inherited, may be congenital. This distinction may be of no practical importance to the victim, but it is of great importance to theory. Some kinds of insanity are probably inherited and others are produced by environmental causes. Authorities agree that physical inheritance is a fact (1,5,14,17,19). The theory of the inheritance of mental characteristics is now almost as generally accepted (6,7,8,18). There is no attempt to minimize the importance of environment or training (11,29,31,32,44). An increasing amount of attention is being given to the importance of the functions of glands of internal secretion as related to behavior and general mental ability (24,25,26,27). Furthermore it is |