Some of the instincts and inborn capacities are not ready to function at birth: they have to grow with the growth of the body. The clearest example of this kind is the sex instinct. In normal children there is little trace of it for ten or a dozen years. Girls arrive at puberty at about the age of thirteen and boys at fourteen, though with a range of several years in either direction. Gregariousness develops slowly, with different phases at different times. The most distinctive phase comes just before puberty, from ten to thirteen, when children develop the "gang" spirit which will be discussed in Chapter V (Primary Groups And Congenial Groups). Mental power, with control over the self and over the environment, grows even more gradually, changing as other capacities mature. It probably does not come to its highest and purest development until after middle life when physical strength begins to fail. The variation in the rate of development, especially in mental power, causes some children in a school to be "retarded" and so to fall out of step with their grade.

One of the most delicate functions of the school is to provide the right stimuli at the right time in the development of each child. Although the instincts are inborn and have their basis in the nervous system, yet they come into action only in response to stimuli. The body, for example, may need food, and the digestive organs be in condition to take care of it, yet there may be no thought of eating until something occurs to suggest it, say the presence of food, or the ringing of the customary dinner bell. The presence of food may arouse the appetite to eat when the body does not need it and would be injured by it. The sex instinct comes at puberty, ready to be called into action by stimulus. Stimulus may cause it to develop earlier than it would otherwise come, and may give it an abnormal growth that will injure health and interfere with the growth of other capacities. These two primitive instincts need no special fostering in normal individuals; they are strong enough by nature. But they do need much wise guidance; the task of education is to control and refine them - to "sublimate" them into sentiments which elevate social life and give greater enjoyment than indulgence in the mere brute appetite can do.

The higher mental capacities, however, being later acquisitions in race history, are in need of stimulus for their development; they also lend themselves more readily to modification by training. Without proper stimulus at the right time in early life they may not develop at all; without wise direction at the right time they may grow into harmful rather than useful qualities. Unless the boy of eight has a chance to make money and learn by experience the advantage of looking ahead before spending it, he may be a spendthrift all his life. The instinct of mastery in a boy of fourteen will become the basis of good manners if he is shown that politeness wins; otherwise it may make him a boor all his life. Since the higher instincts adapt the individual to his environment, it is important that the environment of young persons should approach the ideal type so that each individual, when mature, will help to constitute that kind of environment for everybody.

For we cannot in St. Paul's sense "mortify" our dispositions. If they are not stimulated, they do not therefore die, nor is the human being what he would be if they had never existed. If we leave unstimulated, or, to use a shorter term, if we "baulk" any one of our main dispositions, Curiosity, Property, Trial and Error, Sex, and the rest, we produce in ourselves a state of nervous strain. It may be desirable in any particular case of conduct that we should do so, but we ought to know what we are doing.

The baulking of each disposition produces its own type of strain; but the distinctions between the types are, so far, unnamed and unrecognized, and a trained psychologist would do a real service to civilized life if he would carefully observe and describe them.

One peculiarity of the state of "baulked disposition" is that it is extremely difficult for the sufferer to find his own way out of it. The stimulus must come from outside. - Wallas, The Great Society, pp. 64, 65.

Our primary asset is the undeniable fact that the boy wants to be a man more than he wants anything else in the world. It is a mania with him sometimes, and most of his vices are to be interpreted in the light of it. The imitated swagger and bluster, the awkward attempts at profanity, the early experiments with cigarette and cigar, are not due to any inherent liking for these things, or to a depraved taste, but simply to the overpowering hankering after manhood's estate and the man's characteristics. - Fiske, Boy Life and Self Government, pp. 33, 34.

Whatever theory may be called upon to explain the origin of instinct, however, there can be no doubt that a large number of animals are entirely dependent upon instinctive reactions for adjustment to the environment. Reaction with them is purely mechanical, the same stimulus or combination of the stimuli uniformly giving rise to the same adjustment. Such animals are not able to apply experience to the improvement of adjustment, and are consequently not amenable to the influences of education. At just what point in the animal series the lower limit of educability is to be placed is still a matter of dispute, but it is generally conceded that the mammals, the birds, and at least some of the fishes, are able to profit by experience in varying degrees, while the invertebrates and the primitive protozoa probably lack this capacity. ... In general, then, it may be concluded that educability, meaning by that term the capacity to profit by individual experience, is limited to the vertebrates (and possibly the highly organized invertebrates), and is most pronounced in man and his nearest relatives in the animal kingdom, - the lemurs, monkeys, and anthropoid apes, - together with the animals that man has been able to train for his own service, particularly the horse, the dog, and the elephant.

But while man shares with some of the higher vertebrates the capacity for education, there is one point in which his position is practically unique. Man must be subjected to an educative process before he can complete his development, and this is true in like degree of none of the lower orders. In one sense it is not so much the capacity for education as the necessity of education that differentiates man from the lower animals.

The moment that the moth emerges from its pupa stage it assumes all the functions of an adult member of its species. It does not have to be taught where and how to procure its food; it does not have to be taught where and how to secure shelter or protection against the elements. . . . Two essential points are to be noted in this connection: - the moth can develop into a mature insect without the presence or aid of other insects; furthermore, it can develop into just as good a moth as either of its parents. Man, on the other hand, comes into the world immature; only a very few of the functions of complete development are present at birth. Certain functions, as, for example, nutrition, are operative from the first, and these are based entirely upon instinct. . . . But the instincts that are operative in the infant are obviously much less efficient than those of the lower forms. Even possessing them the infant is a helpless and dependent creature.

. . . But the infant, even if he could reach maturity without the aid of other human beings, would certainly not be so good a man as his father. What he would lack are the great essentials of human life that are transmitted, not directly through the germ cell, but indirectly by social contact, - culture, "education," and civilized habits. . . . - Bagley, The Educative Process, pp. 6-9.