y The youth craves more knowledge of body and mind, that can help against besetting temptations, aid in the choice of a profession, and if his intellect is normal he does not vex his soul overmuch about the logical character of the universe or the ultimate sanction of either truth or virtue. He is more objective than subjective, and only if his lust to know nature and life is starved does his mind trouble him by in-growing. There are new repulsions felt toward home and school, and truancy and runaways abound. The social instincts undergo sudden unfoldment and the new life of love awakens. It is the age of sentiment and of religion, of rapid fluctuation of mood, and the world seems strange and new. Interest in adult life and in vocations develops. Youth awakes to a new world and understands neither it nor himself. The whole future of life depends on how the new powers now given suddenly and in profusion are husbanded and directed. Char- acter and personality are taking form, but everything is plastic. Self-feeling and ambition are increased, and every trait and faculty is liable to exaggeration and excess. It is all a mar- velous new birth, and those who believe that nothing is so worthy of love, reverence, and service as the body and soul of youth, and who hold that the best test of every human institution is how much it contributes to bring youth to the ever fullest possible development, may well review themselves and the civilization in which we live to see how far it satisfies this supreme test.
Never has youth been exposed to such dangers of both ^ perversion and arrest as in our own land and day. Increasing urban life with its temptations, prematurities, sedentary occu- pations, and passive stimuli just when an active, objective life is most needed, early emancipation and a lessening sense for both duty and discipline, the haste to know and do all befitting man's estate before its time, the mad rush for sudden wealth and the reckless fashions set by its gilded youth — all these xvi THE PSYCHOLOGY OF ADOLESCENCE lack some of the regulatives they still have in older lands with more conservative traditions. In a very pregnant psycholog- ical sense ours is an unhistoric land. Our very Constitution had a Minerva birth, and was not the slow growth of prece- dent. Our ideas of freedom were at the outset fevered by the convulsion of the French Revolution. Our literature, customs, fashions, institutions, and legislation were inherited or copied, and our religion was not a gradual indigenous growth, but both its spirit and forms were imported ready-made from Holland, Rome, England, and Palestine. To this extent we are a fiat nation, and in a very significant sense we have had neither childhood nor youth, but have lost touch with these ^stages of life because we lack a normal development history. It is not merely that we have no antiquity rich in material and spiritual monuments that is the best nursery of patriotism in the young, but our gallery of heroes is largely composed, not of glorious youth but of sages advanced in age or old in wisdom for their years. Our immigrants have often passed the best years of youth or leave it behind when they reach our shores, and their memories of it are in other lands. No coun- try is so precociously old for its years. Few as these are, the senescence of the original American stock is already seen in abandoned farms and the infecundity of graduates, so that if our population had been unreplenished from abroad for the last century we should be to-day not merely stationary, like France, but retrogressive. In this environment our young people leap rather than grow into maturity. Our storm and stress strenuousness too often imparts at least the narrow nervous intensity of an individuation that is biologically an- tagonistic to genesis and that is less ephebic, as we fondly think it to be, than ephebeitic. We are conquering nature, ^achieving a magnificent material civilization, leading the world in the applications though not in the creation of science, com- ing to lead in energy and intense industrial and other activities; our vast and complex business organization that has long since outgrown the comprehension of professional economists, ab- sorbs ever more and earlier the best talent and muscle of youth and now dominates health, time, society, politics, and law- giving, and sets new and ever more pervading fashions in manners, morals, education, and religion; but we are pro- PREFACE xvii gressively forgetting that for the complete apprenticeship to Hfe, youth needs repose, leisure, art, legends, romance, ideal- ization, and in a word humanism, if it is to enter the kingdom of man well equipped for man's highest work in the world. In education our very kindergartens, which outnumber those of any other land, by dogma and hyper-sophistication tend to J exterminate the naive that is the glory of childhood. Every- where the mechanical and formal triumph over content and substance, the letter over the spirit, the intellect over morals, lesson setting and hearing over real teaching, the technical over the essential, information over education, marks over edification, and method over matter. We coquet with chil- dren's likes and dislikes and can not teach duty or the spirit of obedience. In no civilized land is teaching so unprofessional ^ or school boards at such a low level of incompetence. No- where are the great traditions of the race so neglected, the high school so oblivious of either the nature or the needs, or both, of the adolescent stage of life. The American college is half universitized with methods and matter prematurely specialized, and half bound to the recitation, marking methods and discipline of the school, while the apex of our educational system is still in Europe, where hundreds of our best gradu- ates go yearly to find the advanced and special training we are still, in most departments, unable to supply.
In religion, which was grafted from an alien ethnic stock, we lack scientific sincerity. Statistics show more sects and more clergymen per capita of population than in any other land, and a rapidly progressive ignorance by the rising gen- eration of the very Bible we profess to revere. Churches, charities, missions abound, but our slums are putrefying sores whose denizens anthropologists believe lower in the moral and intellectual scale than any known race of savages, and the per- centages of juvenile crimes and the average age of first com- mitment grows steadily earlier. We have vastly simplified poli- tics by separating Church and State and by our voluntary sys- tem, but we have also permitted a chasm to yawn between our secular and religious life, between science and theology, till even seminaries for the training of clergymen neglect and even suspect the study of nature as if God were a hypocrite and did one thing in his works and said another in his Word, when xviii THE PSYCHOLOGY OF ADOLESCENCE in fact each supplements and is an imperfect thing without the other. We try to impose not only our civilization, but our religion, upon lower races, even though they are thereby ex- terminated, and fail to study the nature and needs of even those we try to help.
All this is hard on youth, which was better understood in ancient Greece and Rome than now, for it is profoundly re- sponsive to all these influences. Despite all this I am an optimist root and core, not merely because an evolutionist must hold that the best and not the worst will survive and prevail, but because in most, though not yet in all, of these fields I see clearly the beginnings of better things. Even in education and religion, the strongholds of conservatism, there are new and better ideals and efforts, and these are less exceptional and are growing in power and influence and are represented by more and better men. In vigor, enthusiasm, and courage we are still young, and our faults are those of youth. Be- cause they have been great our suffering has been also great, and pain is the world's best teacher whose lessons are surest to be laid to heart. The very fact that we think we are young will make the faith in our future curative, and we shall one day not only attract the youth of the world by our unequaled liberty and opportunity, but develop a mental, moral, and emotional nurture that will be the best preparation for making the most and the best of them and for helping humanity on to a higher stage.
As for years, an almost passionate lover of childhood and a teacher of youth, the adolescent stage of life has long seemed to me one of the most fascinating of all themes, more worthy, perhaps, than anything else in the world of reverence, most inviting study, and in most crying need of a service we do not yet understand how to render aright. Socrates knew that there was no such companionship or inspiration. In minis- tering to it the higher instincts of parenthood culminate and age renews its youth. This should make teaching the most humanistic, the noblest, and the most satisfying vocation of man, as well as the surest safeguard against pessimism. These years are the best decade of life. No age is so responsive to all the best and wisest adult endeavor. In no psychic soil, too, does seed, bad as well as good, strike such deep root, grow PREFACE XIX PREFACE XIX SO rankly, or bear fruit so quickly or so surely. To love and feel for and with the young can alone make the teacher love his calling and respect it as supreme. That it may directly and indirectly help the young to exploit aright all the possibil- ities of the years from fourteen to twenty-four and to safe- guard them against the above insidious dangers is the writer's chief desire. Hence the book attempts a pretty full survey of pedagogic matter and method for the age treated, and also, to some extent, for earlier and later years. To motor educa- tion, grouped under four great divisions, and will-training, one of the longest chapters (III) is devoted. The last part of Chapter XV and Chapter XVI treats of the pedagogy of the English literature and language, history, drawing, normal and high schools, colleges and universities, and philosophy, and Chapter XII is devoted to that of nature and the sciences most commonly taught. Menstruation and the education of girls occupies two chapters (VII and XVII), hygiene, crime, and secret vice one each (IV, V, and VI), social and religious training have each a chapter (XV and XIV, respectively), and the education of the heart is described not only in XI, but in XV, XII, and elsewhere.
This is essentially the author's first book. It has grown slowly under successive repetitions and amplifications as a lecture course to graduate students. It constitutes the first attempt to bring together the various aspects of its vast and complex theme. In revising these lectures for publication, I have eliminated much that was technical and detailed and tried to bring the subject-matter of each chapter within the reach of any intelligent reader. In writing it, I have been most in- debted, especially in the second volume, to my own pupils past and present. I have been throughout also under special obligation to the librarian of the University, Louis N. Wilson, who has for years had my themes in mind and not only ob- tained books difficult of access, but often found valuable refer- ences that I should not otherwise have known. Miss Florence Chandler has not only typographed most of the book and made the name index, but made me in countless ways a debtor to her intelligence and interest. Lastly, Miss Alice Thayer, A. B., has read the entire proof in both galley and page form, and brought her special training in psychology to bear in correct- XX THE PSYCHOLOGY OF ADOLESCENCE ing many errors not only of commission but of omission. To all these my debt can never be repaid. Few authors have ever been more fortunate in their helpers, and I do not like to think what these volumes would have been without their aid.
G. Stanley Hall.
TABLE OF CONTENTS PAGE Preface. v-xx CHAPTER I Growth in Height and Weight i CHAPTER n Growth of Parts and Organs during Adolescence...51 CHAPTER in Growth of Motor Power and Function 129 CHAPTER IV Diseases of Body and Mind...'...237 CHAPTER V Juvenile Faults, Immoralities, and Crimes 325 CHAPTER VI Sexual Development: Its Dangers and Hygiene in Boys..411 CHAPTER VII Periodicity 472 CHAPTER VIII Adolescence in Literature, Biography, and History.. '5^3 XXL ^ CHAPTER I GROWTH IN HEIGHT AND WEIGHT Individual growth recapitulates the history of the race — Rate of prenatal growth in height and weight — Statistical methods — Prenatal growth in animals — Causes that favor and hinder it — Lessened rate at eight to twelve, also at seventeen and eighteen — Delay and compensation — Last stages of growth — Advantages of size — What is growth? — National differences — New genetic theories of retardation and the period of increment — Augmented size and power of the human race — A later, higher, new story superposed on the older foundations now represented in boyhood.
The beginning of individual life, or the age of zero for all sexed animals, is when the male cell penetrates the ovum. Their attraction for each other, which Maupas thinks a relic of the psychochemic tropism of agamic generation, is the bio- logical basis, as the karyonomic rejuvenation thus caused is the goal of love in the ascending stages of life. By their fusion in impregnation these two master cells, the bearers of heredity, acquire the momentum of growth, which next to love is per- haps the most interesting and important fact in the world of organic nature and the key to most of its problems. The new tensions and dominants, to use the terms of Reinke and Mor- gan, thus set free and given definite direction, begin to develop a new individuality, to which the parental one, which now be- gins to wane, is subordinated. With ontogeny in successive generations the immortal germ plasm puts on mortality, somewhat as lost limbs in lower or tissues in higher forms of life are regenerated. The marvelous phenomena of impreg- nation, in which pleasure, which all creatures seek, culminates and in the interest of which beauty, spring-time, blossoms, or- nament, courtship in the animal world, and all physical and psychic secondary sexual qualities and even the life and death of the individual find their key and motive, thus start the long series of anagenic processes that end in complete ma- turity.
As the germ-cell begins to increase in size, its mass or sub- 2 THE PSYCHOLOGY OF ADOLESCENCE stance does so, of course, at a faster rate than does its surface, so that, since all nutrition must first be absorbed from without, a limit is soon reached, and either equilibrium or death by star- vation must ensue. This result, however, is avoided by cell division which begins at the nucleus and proceeds by very com- plex processes, which cytologists have lately made great prog- ress not only in tracing but even in explaining. The first divi- sion results in two smaller daughter-cells of equal size, each of which grows in bulk and weight but does not separate to form each a new individual, as do the primitive unicellular organisms, but divides again, so that their numbers tend to increase in geometrical ratio. These successive generations of daughter- cells which constitute the adult body are thus all descended from a single ovum, and frequency of cell division mainly determines the rapidity of growth. The rate of the latter is high when the generations of cells succeed each other rapidly, and low if the intervals between successive divisions are long. The number of cells thus, as Minot has pointed out,^ depends ideally upon the number of generations, each division effect- ing in some degree a rejuvenation, and an individual or biad being simply a group of cells produced from a single egg.
In this process the individual in a general way repeats the history of its species, passing slowly from the protozoan to the metazoan stage, so that we have all traversed in our own bodies ameboid, helminthoid, piscian, amphibian, anthro- poid, ethnoid, and we know not how many intercalary stages of ascent. How these lines of heredity and growth along which all the many thousand species, extant and extinct, these viatica of the holy spirit of life, the consum- mate products of millennia of the slow travail of evolution, have been unfolded, we know scarcely more than we do what has been the impelling force, or will to live, which seems so inexhaustible and insistent. Certain it is that the cellular theory needs to be supplemented by assuming, both in the organism as a whole and in the species, powers that can not be derived from the cells. Probably, too, the original cause of phylogenetic evolution was no inherent and specific * Minot, C. S. Ueber Vererbung und Verjungung, Biol. Centralbl., August i, 1895. Growth as a Function of Cells, Proc. Nat. Hist. Soc, March 5, 1879. Also Senescence and Rejuvenation, Jour, of Physiol., 1891, No. 2.
GROWTH IN HEIGHT AND WEIGHT 3 nisus, but, as we know it, was due to a struggle for survival forced upon organisms by their environment.
The early stages of growth are telescoped into each other almost indistinguishably, so that phylogenetically the embryo lives a thousand years in a day, and the higher the species the more rapid relatively is the transit through the lower stages. This law of tachygenesis may perhaps be expressed somewhat as follows: Heredity, which slowly appears as a substitute for the external causes that have produced a given series of characters, tends to produce that succession with increasing economy and speed and also to become in a way more independent of the causes which originally deter- mined it.
The human ovum, when ripe for impregnation, has a diameter of about 0.2 mm. Muhlmann ^ has averaged the four best measurements of the monthly embryonic growth in length. To find the prenatal monthly rate of growth in weight, he assumes Welcker's ^ estimate of 0.00008 milli- gram as the weight of a red blood-corpuscle measuring 0.007 mm; then an embryo of the above size would weigh 0.00228 milligram. Assuming with Muhlmann 0.003 iriihi- gram as its weight, these results appear in the following table: Thus at the end of the first month we have the enormous growth in length of 3,650 per cent. If we except the third month, when there seems to be another considerable out- burst of growth in length, the rate of increase is less, though with oscillations in the ratio of decline each month up to birth. Weight, according to the above table, increases from impregnation to birth 905,600,000 fold. Here, too, the law of progressive decline is clear. During the first three months, * Ueber die Ursache des Alters. Wiesbaden, 1900, p. 44 et seq. ' Zeits. f. rat. Med., vol. xx.
4 THE PSYCHOLOGY OF ADOLESCENCE weight increases 400,000,000 per cent; during the next three, 5,182 per cent; and during the three preceding birth, but 252 per cent. Thus the new-born child is millions of times heavier than the ovum in which it started, while in the next twenty-five years the adult will become only about twenty times heavier than at birth. At the third month the cells must therefore have divided twenty-two times if we assume their size and weight equal. Such estimates, of course, are only approximate and more or less conjectural, but it is cer- tain that the growth per cent steadily diminishes during each foetal month. It is as if the nourishment of some of the cells began to suffer very early, and this may perhaps be ascribed to their differing remoteness from nutritive material. On Roux's hypothesis of a struggle for survival between the tis- sues, organs, and cells of the same body for the available food-supply, some have sought to explain even the develop- ment of cavities, folds, and divisions as due to atrophic degen- eration of those cells far from the blood-supply. Indeed, Miihlmann goes so far as to say that there is no other cause in pathology for necrotizing processes, than imperfect nutri- tion. From Weismann's premise that multicellular organisms are differentiated from unicellular by the fact of death, he infers that this latter is due to the symbiosis of the cells, and says " the organism dies because it grows." Growth results in death, or " is constantly digging its own grave." He also infers that the function of cells is determined by their morphologic position in an organism, that it represents noth- ing more than a phenomenon of growth, and that current tele- ological points of view are irrelevant. He even reaches the surprising conclusion that some of the chief structural parts of the body, such as the skeleton, muscles, and nervous system, are products of defective nutrition, and their growth is really a regressive accumulation of inferior products. Folds, con- strictions, hollows, the separation of organs one from another, which are phenomena of growth, may thus be due to the abortion or non-development of cells which are beyond the reach of food. The difference of distribution of nutritive material also causes great variations in the rate of growth of the different organs after they are once differentiated. Thus growth develops their diverse functions.
GROWTH IN HEIGHT AND WEIGHT 5 At birth the child is cast Hke a shipwrecked mariner by angry waves on a strange and unknown coast, and finds itself in a new and rigorous cHmate. Instead of the conditions of fluid pressure equal on all sides, it is now in a stereometric world. Its nascent senses are assailed by new stimuli; the aHmentary canal now comes into full function; the lungs are first inflated with a gasp, the occurrence of which is one of the most easily estabhshed and important medico-legal facts, connected, perhaps, with the characteristic first note of the human voice, which philosophers since Kant have vari- ously interpreted as a sign of pain, a shout of triumph and joy, or a purely mechanical insentient automatism. It is not strange, therefore, that the new-born child rarely gains, and often loses weight during the first few days, small and espe- cially prematurely born infants usually losing more than large ones. Indeed, with all these profound readjustments, the marvel is that the loss is not greater.
At birth the average and maturely born child, about 19J inches long, has a little over one-third the length of body it will attain when adult, but its weight must increase nineteen- or twentyfold. During the first year, it grows about nine inches in length and gains about thirteen pounds, or increases less than one-half its length, but much more than doubles its weight. In both respects the absolute gain of the first year is greater than it will be in any other year of life. During the second year the child should grow in height a trifle over five inches and gain four or five pounds, and by two and one-half years of age should have about one-half its adult height and nearly one-fifth its adult weight. From this point on to the prepubescent accel- eration, which begins at eleven or twelve in girls and nearly two years later in boys, the percentage of growth in both height and weight is rather constant. There is perhaps a little in- crease at seven, and a certain and almost universal retardation, most marked about the tenth year, but extending over several years; this depression in the curve some have wrongly thought complemental to its elevation during the period of pubertal increase. Many children suffer slight and more or less prolonged diminution in both rates during dentition, while some show a retardation and others an acceleration, ascribed to the change of habits beginning with school life. At eighto THE PSYCHOLOGY OF ADOLESCENCE een there is a decided abatement of the energy of growth and an increase of sickness, but one or two years later in boys, especially if under favorable conditions, there often comes a last period of increase, tapering ofT, some think, asymptoically, but generally with irregularities, a period imperfectly known but of the very greatest interest, to final height in the early twenties. Girls are usually slightly less than boys in both weight and height, and twins than single births. Despite Fas- bender's ^ conclusions to the contrary, Boas finds that first-born children exceed those born later, first-born girls excel others from six to maturity, and first-born boys excel from five to fifteen, and perhaps later. The average superiority of the former is lo mm. in height and 1.6 pounds, and that of the latter 7 mm. and 1.2 pounds.
A literature of some threescore very valuable memoirs and tabulations of human growth is now accessible,^ to say nothing of a far larger number of miscellaneous records kept in schools, gymnasia, homes, institutions for special classes, etc. Boas has summed up more comprehensively than any one else averages for the rate of growth in height of Amer- ican children, based upon five of the best special studies of large numbers, viz., in Boston,^ St. Louis,* Milwaukee,^ Worcester,^ Toronto,*^ and Oakland, representing in all, 45,151 boys and 43,298 girls. With a very sHght modification of the age, these results are presented in the following table, which explains itself: ^ Zeits. f. GeburtshUlfe, vol. iii, p. 286.
* Consult for descriptive bibliography as well as for the most comprehensive summary of results Growth of Children in Height and Weight, by Frederic Burk, Am. Jour, of Psy., April, 1898, pp. 253-326.
• The Growth of Children, by H. P. Bowditch. Eighth Annual Rep. Mass. State Board of Health.
* Growth of St. Louis Children, by William T. Porter. Rep. Acad, of Science ©f St. Louis, vol. vi, pp. 263-380.
^ The Growth of Children, by George W. Peckham. Sixth Annual Rep. Wis. State Board of Health.
• Anthropometrische Untersuchungen Uber die Schulkinder in Worcester, Mass., von Gerald M. West. Archiv f. Anthropologie, vol. xxii, 1894, pp. 13-48.
T The Growth of Toronto Children, by Franz Boas. Rep. U. S. Com. of Ed., GROWTH IN HEIGHT AND WEIGHT Table I Boys.
Girls.
Approx- Number of Number of average age.
observa- tions.
Average height for each year.
Absolute annual increase.
Perc'tage annual observa- tions.
Average height for eacn year.
Absolute annual increase.
Perc'tage annual Inches.
Inches.
increase.
Inches.
Inches.
increase.
Hi...I.O The growth of 742 different Amherst students (classes 1885-1901) measured twice a year by Hitchcock, the Amer- ican pioneer in this work, shows the following results for later years: Age.
Number at each age.
Height.
Weight.
Actual in mm.
Per ct. increase.
Actual in kilos.
Per cent.