Emerging adulthood is proposed as a new conception of development for the period from the late teens through the twenties, with a focus on ages 18-25. A theoretical background is presented. Then evidence is provided to support the idea that emerging adulthood is a distinct period demographically, subjectively, and in terms of identity explorations. How emerging adulthood differs from adolescence and young adulthood is explained. Finally, a cultural context for the idea of emerging adulthood is outlined, and it is specified that emerging adulthood exists only in cultures that allow young people a prolonged period of independent role exploration during the late teens and twenties.

/pdf/emerging-adulthood-a-theory-of-development-from-the-late-48n8l4n0g7.pdf

Emerging adulthood. A theory of development from the late teens through the twenties.

Emerging adulthood is proposed as a new conception of development for the period from the late teens through the twenties, with a focus on ages 18-25. A theoretical background is presented, Then evidence is provided to support the idea that emerging adulthood is a distinct period demographically, subjectively, and in terms of identity explorations. How emerging adulthood differs from adolescence and young adulthood is explained. Finally, a cultural context for the idea of emerging adulthood is outlined, and it is specified that emerging adulthood exists only in cultures that allow young people a prolonged period of independent role. exploration during the late teens and twenties.

http://personal.tcu.edu/pwitt/emerging%20adults.pdf

A Theory of Development From the Late Teens Through the Twenties

This chapter suggests that delinquency conceals two distinct categories of individuals, each with a unique natural history and etiology: A small group engages in antisocial behavior of one sort or another at every life stage, whereas a larger group is antisocial only during adolescence. According to the theory of life-course-persistent antisocial behavior, children's neuropsychological problems interact cumulatively with their criminogenic environments across development, culminating m a pathological personality. According to the theory of adolescence-limited antisocial behavior, a contemporary maturity gap encourages teens to mimic antisocial behavior in ways that are normative and adjustive. There are marked individual differences in the stability of antisocial behavior. The chapter reviews the mysterious relationship between age and antisocial behavior. Some youths who refrain from antisocial behavior may, for some reason, not sense the maturity gap and therefore lack the hypothesized motivation for experimenting with crime.

/pdf/adolescence-limited-and-life-course-persistent-antisocial-52vil00qlw.pdf

Adolescence-limited and life-course-persistent antisocial behavior: A developmental taxonomy.

The fat content of the human body has physiological and medical importance. It may influence morbidity and mortality, it may aIter the effectiveness of drugs and anaesthetics, and it may affect the ability to withstand exposure to cold and starvation. Thus the measurement of the total body fat provides useful information. In many people, but by no means everyone, a moderately satisfactory estimate of the body fat content can be obtained from the height and weight. However, for more precise evaluation several methods are available which give a reasonably accurate measure of body fat both in normal subjects and in individuals with unusual body builds. Most of these methods are based on the assumption that the body can be considered to consist of two compartments of relatively constant composition but which are distinctly different; these compartments are: (I) the body fat, which includes the entire content of chemical fat or lipids in the body, and (2) the fat-free mass (FFM), which includes all the rest of the body apart from fat. The body fat compartment is anhydrous, contains no potassium and has a fairly constant density of about 0.90 x 103 kg/m3. The fat-free compartment on the other hand probably has a fairly constant density of about 1.10 x 103 kg/m3, a potassium content of about 68 mequiv./kg in males (about 10% less in females) and a water content of about 720 g/kg. Thus measurement of body density or of total body K or of total body water allows a calculation of the relative proportion of these two compartments in the body and therefore also of the total fat content. The accuracy of these measures, however, is limited by the variability of the composition and density of the fat-free compartment in different individuals. In particular, individuals with a relatively high or

/pdf/body-fat-assessed-from-total-body-density-and-its-estimation-2c3s39jrgr.pdf

Body fat assessed from total body density and its estimation from skinfold thickness: measurements on 481 men and women aged from 16 to 72 years

Mixed longitudinal data on the physical changes at puberty in 228 normal boys are presented together with normal standards for stages of genital and pubic hair development. The genitalia began to develop between the ages 9½ years and 13½ years in 95% of boys (mean = 11.6 ± 0.09) and reached maturity at ages varying between 13 and 17 (mean = 14.9 ± 1.10). The age at which pubic hair first appeared was not accurately determined, but its development through the later stages was studied. It reached the equivalent of an adult female distribution at a mean age of 15.2 ± 0.01 years. On average the genitalia reached the adult stage 3.0 years after they first began to develop; but some boys completed this development in as little as 1.8 years while others took as much as 4.7 years. Some boys complete the whole process in less time than others take to go from Stage G2 to Stage G3. The genitalia begin to develop before pubic hair is visible in photographs in practically all boys. The 41 boys in whom it could be studied reached their maximum rate of growth (peak height velocity) at a mean age of 14.1 ± 0.14 years. Very few boys (about 5%) reached peak height velocity before their genitalia were in Stage 4 and over 20% did not do so until their genitalia were adult. Peak height velocity is reached, on the average, nearly 2 years later in boys than in girls, but the boys9 genitalia begin to develop only about 6 months later than the girls9 breasts. Pubic hair appears about 1½ years later in boys than in girls.

https://adc.bmj.com/content/archdischild/45/239/13.full.pdf

Variations in the Pattern of Pubertal Changes in Boys

In Great Britain some girls begin to menstruate in their 10th or 11th years, while others who are equally healthy may not experience menarche until they 'are 14, 15, or even older. Menarche is, however, only a single event in the combination of physical changes which constitute puberty. The adolescent growth spurt, the development of the breasts, and the growth of the pubic hair occur more or less concurrently, and take, on the average, about 3 years from beginning to completion, with menarche occurring usually in the latter half of this period (Tanner, 1962). At present we lack detailed information about the rate at which girls progress through the stages of puberty and about the relation of one event to another. Only longitudinal studies (i.e. studies in which the same individuals are examined repeatedly over a period of time) can provide this information, which would be helpful both to the clinician in distinguishing the normal from the abnormal, and to the neuro-endocrinologist in constructing hypotheses about the mechanisms by which puberty is controlled. Present knowledge is based on studies carried out on small numbers of children in the United States a generation ago, together with some German studies of a similar period (for literature see Tanner, 1962). The only recent European study in which the events of puberty have been followed longitudinally is the Harpenden Growth Study, which began 19 years ago in England and is still in progress. Anthropometric measurements have been taken, and the development of the breasts and pubic hair have been recorded photographically at 3monthly intervals throughout puberty. Though these data may be subject to certain biases, discussed below, they provide information available from no other source. This paper describes the extent of normal individual variation observed in the events of puberty among the girls of the Harpenden Growth Study. We discuss: (a) variation in the chrono-

https://adc.bmj.com/content/archdischild/44/235/291.full.pdf

Variations in pattern of pubertal changes in girls.

Obese Children. By FLEMMING QUAADE. (Pp. 302. No price given.) Printed by Danish Science Press Ltd., Copenhagen. 1955. This book is the expansion of a prize essay on the subject of obesity in childhood, with special reference to Hilde Bruch's theory on the causation of this condition. Bruch supposed that an ambivalance exists in the attitudes of mothers to their obese children; that they have fundamentally hostile feelings compensated for by more obvious, but more superficial, over-protection and demonstrations of love, manifested by gifts of food. The book make a careful study of 185 obese children, analysing a variety of data and comparing them with similar data from over 1,000 non-obese children. Dr. Quaade eventually comes to two principal conclusions. First, that almost nothing distinguishes obese children from their slimmer friends other than their fatness, together with a characteristic emotional outlook which is not causative but a result of the impact their obesity makes upon their school friends. He concludes that there is little support of Dr. Bruch's thesis regarding the relationship of parents to their obese children. Secondly, he concludes that the main reason why children become fat is because of their excessive appetites, though he bases his opinions on impressions only. Dr. Quaade has nothing to offer regarding why some children's appetites lead them to eat more food and lay down more fat than others, and this surely is the crux of the problem which Dr. Bruch made an attempt to solve. The book is well printed, and though paper backed, is adequately bound. It abounds in tables and charts, and is a useful summary, without making additions to our knowledge, of the statistical facts regarding obesity.

Growth at Adolescence

A new system of dental age assessment.

/pdf/variations-in-pattern-of-pubertal-changes-in-girls-30y8zabc3e.pdf

James M. Tanner

Papers

Variations in pattern of pubertal changes in girls.

Variations in the Pattern of Pubertal Changes in Boys

Growth at Adolescence

A new system of dental age assessment.

Variations in pattern of pubertal changes in girls