His faculty for imitation renders him highly susceptible to the influences of his environment. He imitates what he sees and hears. Therefore the influence of companions for good or evil, as well as the persuasive control of his parents by example, is potent. To a somewhat lesser degree is he affected by the class of literature which he reads. In the absence of stories suited to his psychological needs, he acquires a taste for the dime novel, nickel library, and other blood-and-thunder stories, the reading of which, if continued through the heroic period, frequently results in truancy and leaving home to “see the world.” Concurrent with all the psychic development of this period he shows himself to be a human dynamo of physical energy which manifests itself in ceaseless action. This period of motor activity should find its outlet, as well as its control, in play, athletics, and manual training. He is a bundle of twist, squirm, and wiggle which only time can convert into useful and productive activity. CHAPTER IV ADOLESCENT PSYCHOLOGY The period of adolescence is truly one of storm and stress, caused by the wrecking of boy-nature to rebuild it into man-nature; it is a cataclysmic bursting of the bonds of infancy in preparation for the larger stature of manhood. In early adolescence the boy is neither child nor man. He is in the chrysalis stage of metamorphosis, which is shedding the characteristics of childhood and putting on the maturity of the adult. Neither one nor the other, he is a part of both. Adolescence covers the period of the boy’s life between puberty and maturity. Puberty is the earliest age at which the individual is capable of reproducing the species and it usually begins at the age of thirteen or fourteen, subject to the influence of the factors stated in the preceding chapter. The growth and development of the sex organs during adolescence produce changes which are revolutionary rather than evolutionary in their nature. Marked physical alterations are always attended by still more marked psychic disturbances. The physical indicia of puberty are the lengthening of the vocal cords, which causes the voice to change from the treble of boyhood to the bass of manhood and manifests itself in sudden and uncontrollable breaks in the voice in speaking and singing; the growth of the organs of reproduction and the filling of the seminal glands; the growth of hair on the pubes and face; the coarsening of the skin; broadening of the shoulders, deepening of the chest, and general change from the slenderness of childhood to the compactness of maturity.