Chapter VII: The Chief Cause of Man's lengthened Infancy

The reason for this is that any creature's ability to perceive and to act depends upon the registration of experiences in his nerve-centres. It is either individual or ancestral experience that is thus registered; or, strictly speaking, it is both. It is of the first importance that this point should be clearly understood, and therefore a few words of elementary explanation will not be superfluous.

When you learn to play the piano, you gradually establish innumerable associations between printed groups of notes and the corresponding keys on the key-board, and you also train the fingers to execute a vast number of rapid and complicated motions. The process is full of difficulty, and involves endless repetition. After some years perhaps you can play at sight and with almost automatic ease a polonaise of Liszt or a ballad of Chopin. Now this result is possible only because of a bodily change which has taken place in you. Countless molecular alterations have been wrought in the structure of sundry nerves and muscles, especially in the gray matter of sundry ganglia, or nerve-centres. Every ganglion concerned in the needful adjustments of eyes and fingers and wrists, or in the perception of musical sounds, has undergone a change more or less profound. The nature of the change is largely a matter of speculation; but that point need not in any way concern us. It is enough for us to know that there is such a change, and that it is a registration of experiences. The pianist has registered in the intimate structure of his nervous system a world of experiences entirely foreign to persons unfamiliar with the piano; and upon this registration his capacity depends.

Now the same explanation applies to all bodily movements whatever, whether complicated or simple. In writing, in walking, in talking, we are making use of nervous registrations that have been brought about by an accumulation of experiences. To pick up a pencil from the table may seem a very simple act, yet a baby cannot do it. It has been made possible only by the education of the eyes, of the muscles that move the eyes, of the arm and hand, and of the nerve-centres that coordinate one group of movements with another. All this multiform education has consisted in a gradual registration of experiences. In like manner all the actions of man upon the world about him are made up of movements, and every such movement becomes possible only when a registration is effected in sundry nerve-centres.

But this is not the whole story. The case is undoubtedly the same with those visceral movements, involuntary and in great part unconscious, which sustain life; the beating of the heart, the expansion and contraction of the lungs, the slight changes of calibre in the blood-vessels, even the movements of secretion that take place in glands. All these actions are governed by nerves, and these nerves have had to be educated to their work. This education has been a registration of experiences chiefly ancestral, throughout an enormous past, practically since the beginnings of vertebrate life.

With the earlier and simpler forms of animal existence these visceral movements are the only ones, or almost the only ones, that have to be made. Presently the movements of limbs and sense organs come to be added, and as we rise in the animal scale, these movements come to be endlessly various and complex, and by and by implicate the nervous system more and more deeply in complex acts of perception, memory, reasoning, and volition. Obviously, therefore, in the development of the individual organism the demands of the nervous system upon the vital energies concerned in growth must come to be of paramount importance, and in providing for them the entire embryonic life must be most profoundly and variously affected. Though we may be unable to follow the processes in detail, the truth of this general statement is plain and undeniable.

I say, then, that when a creature's intelligence is low, and its experience very meagre, consisting of a few simple perceptions and acts that occur throughout life with monotonous regularity, all the registration of this experience gets effected in the nerve-centres of its offspring before birth, and they come into the world fully equipped for the battle of life, like the snapping turtle, which snaps with decisive vigour as soon as it emerges from the egg. Nothing is left plastic to be finished after birth, and so the life of each generation is almost an exact repetition of its predecessor. But when a creature's intelligence is high, and its experience varied and complicated, the registration of all this experience in the nerve-centres of its offspring does not get accomplished before birth. There is not time enough. The most important registrations, such as those needed for breathing and swallowing and other indispensable acts, are fully effected; others, such as those needed for handling and walking, are but partially effected; others, such as those involved in the recognition of creatures not important as enemies or prey, are left still further from completion. Much is left to be done by individual experience after birth. The animal, when first born, is a baby dependent upon its mother's care. At the same time its intelligence is far more plastic, and it remains far more teachable, than the lower animal that has no babyhood. Dogs and horses, lions and elephants, often increase in sagacity until late in life; and so do apes, which, along with a higher intelligence than any other dumb animals, have a much longer babyhood.

We are now prepared to appreciate the marvellous beauty of Nature's work in bringing Man upon the scene. Nowhere is there any breach of continuity in the cosmic process. First we have natural selection at work throughout the organic world, bringing forth millions of species of plant and animal, seizing upon every advantage, physical or mental, that enables any species to survive in the universal struggle. So far as any outward observer, back in the Cretaceous or early Eocene periods, could surmise, this sort of confusion might go on forever. But all at once, perhaps somewhere in the upper Eocene or lower Miocene, it appears that among the primates, a newly developing family already distinguished for prehensile capabilities, one genus is beginning to sustain itself more by mental craft and shiftiness than by any physical characteristic. Forthwith does natural selection seize upon any and every advantageous variation in this craft and shiftiness, until this favoured genus of primates, this _Homo Alalus_, or speechless man, as we may call him, becomes preŰminent for sagacity, as the mammoth is preŰminent for bulk, or the giraffe for length of neck.