Mechanistic Psychology
Physiological Foundations of Behavior, by Charles M. Child. New York: Henry
Holt and Company. 330 pages. $5.
Neurological Foundations of Animal Behavior, by C. Judson Herrick. New York:
Henry Holt and Company. 334 pages. $5.
MUCH as I dislike to write a notice of these important biological volumes, not being a biologist, I nevertheless seize the opportunity to do so, because of their unusual psychological and sociological importance. It seems, indeed, that the authors are addressing students of behavior and of society rather more than biologists, and their work is a striking exemplification of a recent statement of Professor Haldane in the New Republic, answering a query as to why he did not become a psychologist:
I do not believe that psychology will go very far without a satisfactory physiology of the nervous system, any more than physiology could advance until physics and chemistry had advanced to a certain point. This is not to say that physiology is a mere branch of physics or chemistry, or the mind a mere by-product of the brain. But it is a fact that we can only know about life by observing the movements of matter. You may
(8)be the most spiritually minded man on earth, but I can only learn that fact by seeing, hearing, or feeling your bodily movements. As the latter depend on events in your brain, I may as well get some information about those events. To study psychology before we understand the physiology of the brain is like trying to understand physics without a knowledge of mathematics. Physics is more than mathematics, as matter is more than space, but you cannot have the one without the other. Now, at the moment the physiology of the nervous system is being worked out with great speed, and by contributing to its progress I suspect that I am doing more for psychology than if I became a psychologist.
Child's work is truly foundational for the question of the limits of environment and heredity. By using chemistry and physics and applying arbitrary stimulations to protoplasmic material he is able to dominate the growth of form and structure in astonishing ways. By altering the chemical and physical environment he can produce a larger or smaller brain, extra eyes, grow an extra head by making a cut at a certain point, or determine the location of the central nervous system by running an electric current in the desired direction. Α stimulus, according to his results, is transmitted through structureless material, such as the amoeba, like waves of water or air or an electric current, and diminishes in intensity in proportion to the distance from the point of primary excitation. Because of this decrement in excitation he calls such a line of stimulation a physiological gradient. In a organic form living in a chemical-physical environment various physiological gradients are produced by the surrounding stimuli; these different gradients represent different rates of living in the different portions of the organism, and the more and less important portions of the internal structure are laid down along the lines of the more and less important gradients. Thus, the head develops from the portion which has the highest rate of living (the most active physiologically) and what other regions become is determined by their position with reference to that most active region. The reason Child is able to produce a head where a tail usually grows is that by making a cut at that point he produces a dominant region of excitation. And this region, because of its superior activity, becomes the brain and the "leader, organizer and integrator" of the remaining organs. For in this connection Child makes it very clear that in addition to an external environment there is an intra-individual environment, the remaining parts forming an environment for each individual part. And between these parts there is both struggle and coöperation. The endocrine substances, for example, to which so much importance is attached at the present moment are chief among the chemical correlators which result from the differentiation of the organs and at the same time assist in this differentiation. It may well be proven, indeed, that they are of supreme importance in regulating and developing what we call "personality" but Child holds that they are after-products, following the development of the organs. They cannot account for the organs since the organs must be present before the chemical substance can be produced.
The development of animal forms is thus not a spontaneous process predetermined in the cell structure; the development of the frog, the bird, the man, is a process of education. Heredity is to be viewed simply as a condition limiting possibilities, not as determining development. But in order to account for the multitude of forms developed side by side in the same environment it is necessary to assume for each form a specific protoplasmic constitution orraw stuff to begin with; a specific kind of protoplasm produces specific structure and behavior in a given environment. As to man, the general structural and functional features are so fixedly determined at the time of birth, awing to the long period of gestation, that they can be but slightly altered afterward by experiment. But the human monsters occasionally born represent precisely the kinds of alterations which the physiologist is able to produce experimentally in the lower animals by altering the physiological gradients. These monsters are experiments which nature has performed, and the physiologist could produce similar specimens if he were able to experiment with the child in utero. On the other hand human character is largely dependent on the cerebral cortex, which develops after birth, and Child's whole claim as to the direct formation of structure and function through immediate stimulation agrees perfectly with the experiments of Pavlov, and the view of those psychologists who hold that habit-formation is as profound in its effects as biological structure, and socially more important, and that practically any desired behavior patterns can be formed in the child by early training.
At many points and on the whole Child's position looks very much like a form of Lamarckianism, though he does not declare himself in that way. He views heredity as no more or less than the memory of past experience—a position taken by Hering some fifty years ago. An excitation, he says, may be transient, but if it persists long enough to produce differences in protoplasmic conditions, long enough to be organically remembered, it may become a physiological axis—that is, determine structure. The protoplasm remembers in the sense that the stimulus leaves effects which persist for a longer or shorter time, and its later behavior is altered by this memory. The establishment of physiological gradients and the growth of structure in this connection are to be regarded as a process of learning.
The author shows himself throughout very sympathetic with the writings of Herbert Spencer. He notes a parallelism in development between the organism and society, and claims that the more simple and primitive forms of social integration and of physiological integration are autocratic, but as evolution progresses this autocratic character becomes less marked in both until in the higher organisms and man the organism approaches a democracy with representative government, as it does in human societies, the reflex responses being superseded to some extent by the deliberative and judicial functions of the cortex, which acts as a general arbiter on all messages from other parts of the body which are important enough to reach it.
The last point, the function of the cortex, is considerably elaborated by Herrick, whose volume is of even greater importance for the problems of society than that of Child, or, more correctly, it is nearer to these problems. Assuming Child's physiological gradients as fundamental, he works out in very fascinating language and with a wealth of illustration the rôle of the nervous system as the organizer of the totality of the body and indicates how the mind arose, not to produce action, but within action, as an instrument for the better control of behavior. Many of his passages are directly social psychology, as, for example, his treatment of the personality at any point of its development as a causative factor in the development of other personalities. Not the least merit of his study is to discredit still further the phantasyings of psychoanalysis which, as he says in a paper read since the appearance of this volume, seems to resemble the facts not more than the Greek Fates resemble the modern biological instrumentalities which have replaced them.
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The two volumes are virtually a collaboration in which, "appealing to no supernatural agencies and to no metaphysical categories," the authors present physiological integration as fundamentally a behavior process. They are not in complete agreement with the Watsonian school of behaviorism, but they represent another school of behaviorism. Let us hope that their colleague, the unique Carlson, will prepare a companion volume on the organization of the glandular and visceral systems.
W. I. THOMAS.
