The end of adolescence and the beginning of adulthood varies by country and by function, and furthermore even within a single nation-state or culture there can be different ages at which an individual is considered to be (chronologically and legally) mature enough to be entrusted by society with certain tasks. Such milestones include, but are not limited to, driving a vehicle, having legal sexual relations, serving in the armed forces or on a jury, purchasing and drinking alcohol, voting, entering into contracts, completing certain levels of education, and marrying.
Adolescence is usually accompanied by an increased independence allowed by the parents or legal guardians and less supervision, contrary to the preadolescence stage.
6 Legal issues, rights and privileges
7 See also
7.1 Human development and psychology
7.1.1 Compare with
In many societies, adolescence was not recognized as a phase of life. Most societies simply distinguished between childhood and adulthood. Stanley Hall is generally credited with "discovering" adolescence with his 1904 study "Adolescence" in which he describes the developmental phase now recognized as adolescence. Hall attributed the new stage to social changes at the turn of the 20th century. Child labor laws kept individuals under 16 out of the work force, and universal education laws kept them in secondary school, thus prolonging the period of dependence — a dependence that allowed them to address psychological tasks they might have ignored when they took on adult roles straight out of childhood.
Upper body of teenage boy. The structure has changed to resemble an adult form.Main article: Puberty Puberty is a period of several years in which rapid physical growth and psychological changes occur, culminating in sexual maturity. The average onset of puberty is at 10 for girls and age 12 for boys. Every person's individual timetable for puberty is influenced primarily by heredity, although environmental factors, such as diet and exercise, also exert some influence. These factors can also contribute to precocious puberty and delayed puberty.
Puberty begins with a surge in hormone production, which in turn causes a number of physical changes. It is also the stage of life in which a child develops secondary sex characteristics (for example, a deeper voice and larger adam's apple in boys, and development of breasts and more curved and prominent hips in girls) as his or her hormonal balance shifts strongly towards an adult state. This is triggered by the pituitary gland, which secretes a surge of hormonal agents into the blood stream, initiating a chain reaction. The male and female gonads are subsequently activated, which puts them into a state of rapid growth and development; the triggered gonads now commence the mass production...