Adolescence

Adolescence

Overview

Adolescence is a transitional stage of physical and mental human development
Human development (biology)
Human development is the process of growing to maturity. In biological terms, this entails growth from a one-celled zygote to an adult human being.- Biological development:...

 generally occurring between puberty
Puberty
Puberty is the process of physical changes by which a child's body matures into an adult body capable of reproduction, as initiated by hormonal signals from the brain to the gonads; the ovaries in a girl, the testes in a boy...

 and legal adult
Adult
An adult is a human being or living organism that is of relatively mature age, typically associated with sexual maturity and the attainment of reproductive age....

hood (age of majority
Age of majority
The age of majority is the threshold of adulthood as it is conceptualized in law. It is the chronological moment when minors cease to legally be considered children and assume control over their persons, actions, and decisions, thereby terminating the legal control and legal responsibilities of...

), but largely characterized as beginning and ending with the teenage stage. According to Erik Erikson
Erik Erikson
Erik Erikson was a Danish-German-American developmental psychologist and psychoanalyst known for his theory on social development of human beings. He may be most famous for coining the phrase identity crisis. His son, Kai T...

's stages of human development
Erikson's stages of psychosocial development
Erikson's stages of psychosocial development as articulated by Erik Erikson explain eight stages through which a healthily developing human should pass from infancy to late adulthood. In each stage the person confronts, and hopefully masters, new challenges. Each stage builds on the successful...

, for example, a young adult
Young adult (psychology)
A young adult, according to Erik Erikson's stages of human development, is generally a person between the age of 20 - 40, whereas an adolescent is a person between the age of 13 - 19, although definitions and opinions vary. The young adult stage in human development precedes middle adulthood. A...

 is generally a person between the ages of 20 and 40, whereas an adolescent is a person between the ages of 13 and 19. Historically, puberty has been heavily associated with teenagers and the onset of adolescent development.
Discussion
Ask a question about 'Adolescence'
Start a new discussion about 'Adolescence'
Answer questions from other users
Full Discussion Forum
 
Unanswered Questions
Encyclopedia

Adolescence is a transitional stage of physical and mental human development
Human development (biology)
Human development is the process of growing to maturity. In biological terms, this entails growth from a one-celled zygote to an adult human being.- Biological development:...

 generally occurring between puberty
Puberty
Puberty is the process of physical changes by which a child's body matures into an adult body capable of reproduction, as initiated by hormonal signals from the brain to the gonads; the ovaries in a girl, the testes in a boy...

 and legal adult
Adult
An adult is a human being or living organism that is of relatively mature age, typically associated with sexual maturity and the attainment of reproductive age....

hood (age of majority
Age of majority
The age of majority is the threshold of adulthood as it is conceptualized in law. It is the chronological moment when minors cease to legally be considered children and assume control over their persons, actions, and decisions, thereby terminating the legal control and legal responsibilities of...

), but largely characterized as beginning and ending with the teenage stage. According to Erik Erikson
Erik Erikson
Erik Erikson was a Danish-German-American developmental psychologist and psychoanalyst known for his theory on social development of human beings. He may be most famous for coining the phrase identity crisis. His son, Kai T...

's stages of human development
Erikson's stages of psychosocial development
Erikson's stages of psychosocial development as articulated by Erik Erikson explain eight stages through which a healthily developing human should pass from infancy to late adulthood. In each stage the person confronts, and hopefully masters, new challenges. Each stage builds on the successful...

, for example, a young adult
Young adult (psychology)
A young adult, according to Erik Erikson's stages of human development, is generally a person between the age of 20 - 40, whereas an adolescent is a person between the age of 13 - 19, although definitions and opinions vary. The young adult stage in human development precedes middle adulthood. A...

 is generally a person between the ages of 20 and 40, whereas an adolescent is a person between the ages of 13 and 19. Historically, puberty has been heavily associated with teenagers and the onset of adolescent development. However, the start of puberty has had somewhat of an increase in preadolescence (particularly females, as seen with early and precocious puberty
Precocious puberty
As a medical term, precocious puberty describes puberty occurring at an unusually early age. In most of these children, the process is normal in every respect except the unusually early age, and simply represents a variation of normal development. In a minority of children, the early development is...

), and adolescence has had an occasional extension beyond the teenage years (typically males) compared to previous generations. These changes have made it more difficult to rigidly define the time frame in which adolescence occurs.

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.

In studying adolescent development, adolescence can be defined biologically, as the physical transition marked by the onset of puberty and the termination of physical growth; cognitively, as changes in the ability to think abstractly and multi-dimensionally; or socially, as a period of preparation for adult role. Major pubertal and biological changes include changes to the sex organ
Sex organ
A sex organ, or primary sexual characteristic, as narrowly defined, is any of the anatomical parts of the body which are involved in sexual reproduction and constitute the reproductive system in a complex organism; flowers are the reproductive organs of flowering plants, cones are the reproductive...

s, height, weight, and muscle mass, as well as major changes in brain structure and organization. Cognitive
Cognition
In science, cognition refers to mental processes. These processes include attention, remembering, producing and understanding language, solving problems, and making decisions. Cognition is studied in various disciplines such as psychology, philosophy, linguistics, and computer science...

 advances encompass both increases in knowledge and in the ability to think abstractly and to reason more effectively. The study of adolescent development often involves interdisciplinary collaborations. For example, researchers in neuroscience
Neuroscience
Neuroscience is the scientific study of the nervous system. Traditionally, neuroscience has been seen as a branch of biology. However, it is currently an interdisciplinary science that collaborates with other fields such as chemistry, computer science, engineering, linguistics, mathematics,...

 or bio-behavioral health
Behavioral medicine
Behavioral medicine is an interdisciplinary field of medicine concerned with the development and integration of knowledge in the biological, behavioral, psychological, and social sciences relevant to health and illness...

 might focus on pubertal changes in brain structure and its effects on cognition or social relations. Sociologists
Sociology
Sociology is the study of society. It is a social science—a term with which it is sometimes synonymous—which uses various methods of empirical investigation and critical analysis to develop a body of knowledge about human social activity...

 interested in adolescence might focus on the acquisition of social roles (e.g., worker or romantic partner) and how this varies across cultures or social conditions. Developmental psychologists
Developmental psychology
Developmental psychology, also known as human development, is the scientific study of systematic psychological changes, emotional changes, and perception changes that occur in human beings over the course of their life span. Originally concerned with infants and children, the field has expanded to...

 might focus on changes in relations with parents and peers as a function of school structure and pubertal status.

History


In many societies throughout history, 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
Secondary school
Secondary school is a term used to describe an educational institution where the final stage of schooling, known as secondary education and usually compulsory up to a specified age, takes place...

, 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.

General


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 or 11 for girls and age 12 or 13 for boys. Every person's individual timetable for puberty is influenced primarily by heredity
Heredity
Heredity is the passing of traits to offspring . This is the process by which an offspring cell or organism acquires or becomes predisposed to the characteristics of its parent cell or organism. Through heredity, variations exhibited by individuals can accumulate and cause some species to evolve...

, although environmental factors, such as diet and exercise, also exert some influence. These factors can also contribute to precocious
Precocious puberty
As a medical term, precocious puberty describes puberty occurring at an unusually early age. In most of these children, the process is normal in every respect except the unusually early age, and simply represents a variation of normal development. In a minority of children, the early development is...

 and delayed puberty
Delayed puberty
Puberty is described as delayed puberty with exceptions when an organism has passed the usual age of onset of puberty with no physical or hormonal signs that it is beginning. Puberty may be delayed for several years and still occur normally, in which case it is considered constitutional delay, a...

.

Some of the most significant parts of pubertal development involve distinctive physiological changes in individuals' height, weight, body composition, and circulatory
Circulatory system
The circulatory system is an organ system that passes nutrients , gases, hormones, blood cells, etc...

 and respiratory
Respiratory system
The respiratory system is the anatomical system of an organism that introduces respiratory gases to the interior and performs gas exchange. In humans and other mammals, the anatomical features of the respiratory system include airways, lungs, and the respiratory muscles...

 systems. These changes are largely influenced by hormonal activity. Hormones play an organizational role, priming the body to behave in a certain way once puberty begins, and an activational role, referring to changes in hormones during adolescence that trigger behavioral and physical changes.

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
Child
Biologically, a child is generally a human between the stages of birth and puberty. Some vernacular definitions of a child include the fetus, as being an unborn child. The legal definition of "child" generally refers to a minor, otherwise known as a person younger than the age of majority...

 develops secondary sex characteristic
Secondary sex characteristic
Secondary sex characteristics are features that distinguish the two sexes of a species, but that are not directly part of the reproductive system. They are believed to be the product of sexual selection for traits which give an individual an advantage over its rivals in courtship and aggressive...

s (for example, a deeper voice and larger adam's apple
Adam's apple
The laryngeal prominence—commonly known as the Adam's Apple—is a feature of the human neck. This lump, or protrusion, is formed by the angle of the thyroid cartilage surrounding the larynx...

 in boys, and development of breast
Breast
The breast is the upper ventral region of the torso of a primate, in left and right sides, which in a female contains the mammary gland that secretes milk used to feed infants.Both men and women develop breasts from the same embryological tissues...

s and more curved and prominent hips
HIPS
HIPS may refer to:* High impact polystyrene* Home Information Pack* Host-based intrusion-prevention system, a computer security system oriented towards workstations...

 in girls) as his or her hormonal balance shifts strongly towards an adult state. This is triggered by the pituitary gland
Pituitary gland
In vertebrate anatomy the pituitary gland, or hypophysis, is an endocrine gland about the size of a pea and weighing 0.5 g , in humans. It is a protrusion off the bottom of the hypothalamus at the base of the brain, and rests in a small, bony cavity covered by a dural fold...

, which secretes a surge of hormonal
Hormone
A hormone is a chemical released by a cell or a gland in one part of the body that sends out messages that affect cells in other parts of the organism. Only a small amount of hormone is required to alter cell metabolism. In essence, it is a chemical messenger that transports a signal from one...

 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 of the necessary chemicals. The testes primarily release testosterone
Testosterone
Testosterone is a steroid hormone from the androgen group and is found in mammals, reptiles, birds, and other vertebrates. In mammals, testosterone is primarily secreted in the testes of males and the ovaries of females, although small amounts are also secreted by the adrenal glands...

, and the ovaries predominantly dispense estrogen
Estrogen
Estrogens , oestrogens , or œstrogens, are a group of compounds named for their importance in the estrous cycle of humans and other animals. They are the primary female sex hormones. Natural estrogens are steroid hormones, while some synthetic ones are non-steroidal...

. The production of these hormones increases gradually until sexual maturation is met. Some boys may develop gynecomastia
Gynecomastia
Gynecomastia or Gynaecomastia, , is the abnormal development of large mammary glands in males resulting in breast enlargement. The term comes from the Greek γυνή gyné meaning "woman" and μαστός mastós meaning "breast"...

 due to an imbalance of sex hormones, tissue responsiveness or obesity
Obesity
Obesity is a medical condition in which excess body fat has accumulated to the extent that it may have an adverse effect on health, leading to reduced life expectancy and/or increased health problems...

.

Facial hair
Facial hair
Facial hair is a secondary sex characteristic of human males. Men often start developing facial hair in the later years of puberty or adolescence, approximately between 17–20 years of age, and most do not finish developing a fully adult beard until their early 20s or even later...

 in males normally appears in a specific order during puberty: The first facial hair to appear tends to grow at the corners of the upper lip, typically between 14 to 16 years of age. It then spreads to form a moustache
Moustache
A moustache is facial hair grown on the outer surface of the upper lip. It may or may not be accompanied by a type of beard, a facial hair style grown and cropped to cover most of the lower half of the face.-Etymology:...

 over the entire upper lip. This is followed by the appearance of hair on the upper part of the cheeks, and the area under the lower lip. The hair eventually spreads to the sides and lower border of the chin, and the rest of the lower face to form a full beard. As with most human biological processes, this specific order may vary among some individuals. Facial hair is often present in late adolescence, around ages 17 and 18, but may not appear until significantly later. Some men do not develop full facial hair for 10 years after puberty. Facial hair will continue to get coarser, darker and thicker for another 2–4 years after puberty.

The major landmark of puberty for males is the first ejaculation
Ejaculation
Ejaculation is the ejecting of semen from the male reproductory tract, and is usually accompanied by orgasm. It is usually the final stage and natural objective of male sexual stimulation, and an essential component of natural conception. In rare cases ejaculation occurs because of prostatic disease...

, which occurs, on average, at age 13. For females, it is menarche
Menarche
Menarche is the first menstrual cycle, or first menstrual bleeding, in female human beings. From both social and medical perspectives it is often considered the central event of female puberty, as it signals the possibility of fertility....

, the onset of menstruation, which occurs, on average, between ages 12 and 13. The age of menarche is influenced by heredity, but a girl's diet and lifestyle contribute as well. Regardless of genes, a girl must have certain proportion of body fat to attain menarche. Consequently, girls who have a high-fat diet and who are not physically active begin menstruating earlier, on average, than girls whose diet contains less fat and whose activities involve fat reducing exercise (e.g. ballet and gymnastics). Girls who experience malnutrition or are in societies in which children are expected to perform physical labor also begin menstruating at later ages.

The timing of puberty can have important psychological and social consequences. Early maturing boys are usually taller and stronger than their friends. They have the advantage in capturing the attention of potential partners and in becoming hand-picked for sports. Pubescent boys often tend to have a good body image, are more confident, secure, and more independent. Late maturing boys can be less confident because of poor body image when comparing themselves to already developed friends and peers. However, early puberty is not always positive for boys; early sexual maturation in boys can be accompanied by increased aggressiveness due to the surge of hormones that affect them. Because they appear older than their peers, pubescent boys may face increased social pressure to conform to adult norms; society may view them as more emotionally advanced, despite the fact that their cognitive
Cognition
In science, cognition refers to mental processes. These processes include attention, remembering, producing and understanding language, solving problems, and making decisions. Cognition is studied in various disciplines such as psychology, philosophy, linguistics, and computer science...

 and social development may lag behind their appearance. Studies have shown that early maturing boys are more likely to be sexually active and are more likely to participate in risky behaviors.

For girls early maturation can sometimes lead to increased self-consciousness, though a typical aspect in maturing females. Because of their bodies' developing in advance, pubescent girls can become more insecure. Consequently, girls that reach sexual maturation early are more likely than their peers to develop eating disorders. Nearly half of all American high school girls' diet is to lose weight. In addition, girls may have to deal with sexual advances from older boys before they are emotionally and mentally mature. In addition to having earlier sexual experiences and more unwanted pregnancies than late maturing girls, early maturing girls are more exposed to alcohol
Alcoholic beverage
An alcoholic beverage is a drink containing ethanol, commonly known as alcohol. Alcoholic beverages are divided into three general classes: beers, wines, and spirits. They are legally consumed in most countries, and over 100 countries have laws regulating their production, sale, and consumption...

 and drug abuse
Drug abuse
Substance abuse, also known as drug abuse, refers to a maladaptive pattern of use of a substance that is not considered dependent. The term "drug abuse" does not exclude dependency, but is otherwise used in a similar manner in nonmedical contexts...

. Those who have had such experiences tend to perform less well in school than their "inexperienced" age peers.

Girls have usually reached full physical development by ages 15–17, while boys usually complete puberty by ages 16–18. Any increase in height beyond the post-pubertal age is uncommon. Girls attain reproductive maturity about 4 years after the first physical changes of puberty appear. In contrast, boys accelerate more slowly but continue to grow for about 6 years after the first visible pubertal changes.


Growth spurt


The adolescent growth spurt is a rapid increase in individuals' height
Human height
Human height is the distance from the bottom of the feet to the top of the head in a human body standing erect.When populations share genetic background and environmental factors, average height is frequently characteristic within the group...

 and weight during puberty resulting from the simultaneous release of growth hormones, thyroid hormone
Thyroid hormone
The thyroid hormones, thyroxine and triiodothyronine , are tyrosine-based hormones produced by the thyroid gland primarily responsible for regulation of metabolism. An important component in the synthesis of thyroid hormones is iodine. The major form of thyroid hormone in the blood is thyroxine ,...

s, and androgens. Males experience their growth spurt about two years later, on average, than females. During their peak height velocity (the time of most rapid growth), adolescents grow at a growth rate nearly identical to that of a toddler—about 4 inches (10.3 cm) a year for males and 3.5 inches (9 cm) for females. In addition to changes in height, adolescents also experience a significant increase in weight (Marshall, 1978). The weight gained during adolescence constitutes nearly half of one's adult body weight. Teenage and early adult males may continue to gain natural muscle growth even after puberty.

The accelerated growth in different body parts happens at different times, but for all adolescents it has a fairly regular sequence. The first places to grow are the extremities—the head, hands, and feet—followed the arms and legs, then the torso and shoulders. This non-uniform growth is one reason why an adolescent body may seem to be out of proportion.

During puberty, bones become harder and more brittle. At the conclusion of puberty, the ends of the long bones close during the process called epiphysis
Epiphysis
The epiphysis is the rounded end of a long bone, at its joint with adjacent bone. Between the epiphysis and diaphysis lies the metaphysis, including the epiphyseal plate...

. There are ethnic differences in these skeletal changes: bone density increases significantly more among African-American than white adolescents, which might account for decreased likelihood of African-American women developing osteoporosis
Osteoporosis
Osteoporosis is a disease of bones that leads to an increased risk of fracture. In osteoporosis the bone mineral density is reduced, bone microarchitecture is deteriorating, and the amount and variety of proteins in bone is altered...

 and having fewer bone fractures.

Another set of significant physical changes during puberty happen in bodily distribution of fat and muscle. This process is different for females and males. Before puberty, there are nearly no sex differences in fat and muscle distribution; during puberty, boys grow muscle much faster than girls, although both sexes experience rapid muscle development. In contrast, though both sexes experience an increase in body fat, the increase much more significant for girls. Frequently, the increase in fat for girls happens in their years just before puberty. The ratio between muscle and fat among post-pubertal boys is around three to one, while for girls it is about five to four. This may help explain sex differences in athletic performance.

Pubertal development also affects circulatory
Circulatory system
The circulatory system is an organ system that passes nutrients , gases, hormones, blood cells, etc...

 and respiratory
Respiratory system
The respiratory system is the anatomical system of an organism that introduces respiratory gases to the interior and performs gas exchange. In humans and other mammals, the anatomical features of the respiratory system include airways, lungs, and the respiratory muscles...

 systems as an adolescents' heart and lungs increase in both size and capacity. These changes lead to increased strength and tolerance for exercise. Sex differences are apparent as males tend to develop "larger hearts and lungs, higher systolic blood pressure, a lower resting heart rate, a greater capacity for carrying oxygen to the blood, a greater power for neutralizing the chemical products of muscular exercise, higher blood hemoglobin and more red blood cells".

It is important to note that, despite some genetic sex differences, environmental factors play a large role in biological changes during adolescence. For example, girls tend to reduce their physical activity in preadolescence and may receive inadequate nutrition from diets that often lack important nutrients, such as iron. These environmental influences in turn affect female physical development.

Primary sex characteristics


Primary sex characteristics
Sex organ
A sex organ, or primary sexual characteristic, as narrowly defined, is any of the anatomical parts of the body which are involved in sexual reproduction and constitute the reproductive system in a complex organism; flowers are the reproductive organs of flowering plants, cones are the reproductive...

 are those directly related to the sex organs. In males, the first stages of puberty involve growth of the testes and scrotum, followed by growth of the penis. At the time that the penis develops, the seminal vesicles, the prostate, and the bilbo-urethral glands also enlarge and develop. The first ejaculation of seminal fluid generally occurs about one year after the beginning of accelerated penis growth, although this is often determined culturally rather than biologically, since for many boys first ejaculation occurs as a result of masturbation. Boys are generally fertile before they have an adult appearance

In females, changes in the primary sex characteristics involve growth of the uterus, vagina, and other aspects of the reproductive system. Menarche
Menarche
Menarche is the first menstrual cycle, or first menstrual bleeding, in female human beings. From both social and medical perspectives it is often considered the central event of female puberty, as it signals the possibility of fertility....

, the beginning of menstruation, is a relatively late development which follows a long series of hormonal changes. Generally, a girl is not fully fertile until several years after menarche, as regular ovulation follows menarche by about two years. Unlike males, therefore, females usually appear physically mature before they are capable of becoming pregnant.

Secondary sex characteristics


Changes in secondary sex characteristic
Secondary sex characteristic
Secondary sex characteristics are features that distinguish the two sexes of a species, but that are not directly part of the reproductive system. They are believed to be the product of sexual selection for traits which give an individual an advantage over its rivals in courtship and aggressive...

s include every change that is not directly related to sexual reproduction. In males, these changes involve appearance of pubic, facial, and body hair, deepening of the voice, roughening of the skin around the upper arms and thighs, and increased development of the sweat glands. In females, secondary sex changes involve elevation of the breast, widening of the hips, development of pubic and underarm hair, widening of the areolae, and elevation of the nipples.

The changes in secondary sex characteristics that take place during puberty are often referred to in terms of five Tanner stages, named after the British pediatrician who devised the categorization system.

Changes in the brain


The human brain is not fully developed by the time a person reaches puberty. Between the ages of 10 and 25, the brain undergoes changes that have important implications for behavior (see Cognitive development below).

The brain reaches 90% of its adult size by the time a person is six years of age. Thus, the brain does not grow in size much during adolescence. However, the creases in the brain continue to become more complex until the late teens. The biggest changes in the folds of the brain during this time occur in the parts of the cortex that process cognitive and emotional information.

Over the course of adolescence, the amount of white matter
White matter
White matter is one of the two components of the central nervous system and consists mostly of myelinated axons. White matter tissue of the freshly cut brain appears pinkish white to the naked eye because myelin is composed largely of lipid tissue veined with capillaries. Its white color is due to...

 in the brain increases linearly, while the amount of grey matter
Grey matter
Grey matter is a major component of the central nervous system, consisting of neuronal cell bodies, neuropil , glial cells and capillaries. Grey matter contains neural cell bodies, in contrast to white matter, which does not and mostly contains myelinated axon tracts...

 in the brain follows an inverted-U pattern. Through a process called synaptic pruning
Synaptic pruning
In neuroscience, synaptic pruning, neuronal pruning or axon pruning refer to neurological regulatory processes, which facilitate a change in neural structure by reducing the overall number of neurons or connections, leaving more efficient synaptic configurations. Pruning is a neurological...

, unnecessary neuronal connections in the brain are eliminated and the amount of grey matter is pared down. However, this does not mean that the brain loses functionality; rather, it becomes more efficient due to increased myelination (insulation of axons) and the reduction of unused pathways.

The first areas of the brain to be pruned are those involving primary functions, such as motor and sensory areas. The areas of the brain involved in more complex processes lose matter later in development. These include the lateral and prefrontal
Prefrontal cortex
The prefrontal cortex is the anterior part of the frontal lobes of the brain, lying in front of the motor and premotor areas.This brain region has been implicated in planning complex cognitive behaviors, personality expression, decision making and moderating correct social behavior...

 cortices, among other regions.

Some of the most developmentally significant changes in the brain occur in the prefrontal cortex
Prefrontal cortex
The prefrontal cortex is the anterior part of the frontal lobes of the brain, lying in front of the motor and premotor areas.This brain region has been implicated in planning complex cognitive behaviors, personality expression, decision making and moderating correct social behavior...

, which is involved in decision-making and cognitive control, as well as other higher cognitive functions. During adolescence, myelination and synaptic pruning in the prefrontal cortex increases, improving the efficiency of information processing, and neural connections between the prefrontal cortex and other regions of the brain are strengthened. This leads to better evaluation of risks and rewards, as well as improved control over impulses. Specifically, developments in the dorsolateral prefrontal cortex are important for controlling impulses and planning ahead, while development in the ventromedial prefrontal cortex is important for decision making. Changes in the orbitofrontal cortex are important for evaluating rewards and risks.

Two neurotransmitter
Neurotransmitter
Neurotransmitters are endogenous chemicals that transmit signals from a neuron to a target cell across a synapse. Neurotransmitters are packaged into synaptic vesicles clustered beneath the membrane on the presynaptic side of a synapse, and are released into the synaptic cleft, where they bind to...

s that play important roles in adolescent brain development are glutamate and dopamine
Dopamine
Dopamine is a catecholamine neurotransmitter present in a wide variety of animals, including both vertebrates and invertebrates. In the brain, this substituted phenethylamine functions as a neurotransmitter, activating the five known types of dopamine receptors—D1, D2, D3, D4, and D5—and their...

. Glutamate is an excitatory neurotransmitter. During the synaptic pruning that occurs during adolescence, most of the neural connections that are pruned contain receptors for glutamate or other excitatory neurotransmitters. Because of this, by early adulthood the synaptic balance in the brain is more inhibitory than excitatory.

Dopamine
Dopamine
Dopamine is a catecholamine neurotransmitter present in a wide variety of animals, including both vertebrates and invertebrates. In the brain, this substituted phenethylamine functions as a neurotransmitter, activating the five known types of dopamine receptors—D1, D2, D3, D4, and D5—and their...

 is associated with pleasure and attuning to the environment during decision-making. During adolescence, dopamine levels in the limbic system
Limbic system
The limbic system is a set of brain structures including the hippocampus, amygdala, anterior thalamic nuclei, septum, limbic cortex and fornix, which seemingly support a variety of functions including emotion, behavior, long term memory, and olfaction. The term "limbic" comes from the Latin...

 increase and input of dopamine to the prefrontal cortex increases. The balance of excitatory to inhibitory neurotransmitters and increased dopamine activity in adolescence may have implications for adolescent risk-taking and vulnerability to boredom (see Cognitive development, below). Development in the limbic system
Limbic system
The limbic system is a set of brain structures including the hippocampus, amygdala, anterior thalamic nuclei, septum, limbic cortex and fornix, which seemingly support a variety of functions including emotion, behavior, long term memory, and olfaction. The term "limbic" comes from the Latin...

 plays an important role in determining rewards and punishments and processing emotional experience and social information. Changes in the levels of the neurotransmitters dopamine
Dopamine
Dopamine is a catecholamine neurotransmitter present in a wide variety of animals, including both vertebrates and invertebrates. In the brain, this substituted phenethylamine functions as a neurotransmitter, activating the five known types of dopamine receptors—D1, D2, D3, D4, and D5—and their...

 and serotonin
Serotonin
Serotonin or 5-hydroxytryptamine is a monoamine neurotransmitter. Biochemically derived from tryptophan, serotonin is primarily found in the gastrointestinal tract, platelets, and in the central nervous system of animals including humans...

 in the limbic system make adolescents more emotional and more responsive to rewards and stress. The corresponding increase in emotional variability also can increase adolescents’ vulnerability.

Psychology


Adolescence is a developmental disturbance.
-Anna Freud
Anna Freud
Anna Freud was the sixth and last child of Sigmund and Martha Freud. Born in Vienna, she followed the path of her father and contributed to the newly born field of psychoanalysis...


Adolescence is characterized by a number of cognitive, emotional, physical
Human body
The human body is the entire structure of a human organism, and consists of a head, neck, torso, two arms and two legs.By the time the human reaches adulthood, the body consists of close to 100 trillion cells, the basic unit of life...

 and attitudinal
Attitude (psychology)
An attitude is a hypothetical construct that represents an individual's degree of like or dislike for something. Attitudes are generally positive or negative views of a person, place, thing, or event— this is often referred to as the attitude object...

 changes, which can be a cause of conflict on one hand and positive personality development on the other.

The home environment and parents are still important for the behaviors and choices of adolescents. Adolescents who have a good relationship with their parents are less likely to engage in various risk behaviors, such as smoking, drinking, fighting, and/or unprotected sexual intercourse
Sexual intercourse
Sexual intercourse, also known as copulation or coitus, commonly refers to the act in which a male's penis enters a female's vagina for the purposes of sexual pleasure or reproduction. The entities may be of opposite sexes, or they may be hermaphroditic, as is the case with snails...

. In conflict with their parents, adolescents are more flexible than younger children, but more hostile and rigid compared to adults. The topics of conflicts between adolescents and their parents are often about the extent to which parents can control and supervise the adolescent, for instance conflicts about chores, schoolwork, curfew, and the adolescent's right to privacy.

For the first time in their lives adolescents may start to view their friends, their peer group
Peer group
A peer group is a social group consisting of humans. Peer groups are an informal primary group of people who share a similar or equal status and who are usually of roughly the same age, tended to travel around and interact within the social aggregate Members of a particular peer group often have...

, as more important and influential than their parents or guardians. Peer groups offer its members the opportunity to develop various social skills, such as empathy, sharing and leadership. Peer groups can have positive influences on an individual, for instance on academic motivation and performance, but they can also have negative influences and lead to an increase in experimentation with drugs, drinking, vandalism, and stealing. Susceptibility to peer pressure
Peer pressure
Peer pressure refers to the influence exerted by a peer group in encouraging a person to change his or her attitudes, values, or behavior in order to conform to group norms. Social groups affected include membership groups, when the individual is "formally" a member , or a social clique...

 increases during early adolescence, peaks around age 14, and declines thereafter.

In the search for a unique social identity
Identity (social science)
Identity is a term used to describe a person's conception and expression of their individuality or group affiliations . The term is used more specifically in psychology and sociology, and is given a great deal of attention in social psychology...

 for themselves, adolescents are frequently upset. G. Stanley Hall
G. Stanley Hall
Granville Stanley Hall was a pioneering American psychologist and educator. His interests focused on childhood development and evolutionary theory...

 denoted this period as one of "Storm and Stress" and, according to him, conflict at this developmental stage is normal and not unusual. Margaret Mead
Margaret Mead
Margaret Mead was an American cultural anthropologist, who was frequently a featured writer and speaker in the mass media throughout the 1960s and 1970s....

, on the other hand, attributed the behavior of adolescents to their culture and upbringing.

Adolescence is also a time for rapid cognitive development. Piaget
Jean Piaget
Jean Piaget was a French-speaking Swiss developmental psychologist and philosopher known for his epistemological studies with children. His theory of cognitive development and epistemological view are together called "genetic epistemology"....

 describes adolescence as the stage of life in which the individual's thoughts start taking more of an abstract form and the egocentric thoughts decrease. This allows the individual to think and reason in a wider perspective. A combination of behavioural and fMRI studies have demonstrated development of executive functions
Executive functions
The executive system is a theorized cognitive system in psychology that controls and manages other cognitive processes. It is responsible for processes that are sometimes referred to as the executive function, executive functions, supervisory attentional system, or cognitive control...

, that is, cognitive skills that enable the control and coordination of thoughts and behaviour, which are generally associated with the prefrontal cortex
Prefrontal cortex
The prefrontal cortex is the anterior part of the frontal lobes of the brain, lying in front of the motor and premotor areas.This brain region has been implicated in planning complex cognitive behaviors, personality expression, decision making and moderating correct social behavior...

. The thoughts, ideas and concepts developed at this period of life greatly influence one's future life, playing a major role in character and personality formation.

Positive psychology
Positive psychology
Positive psychology is a recent branch of psychology whose purpose was summed up in 1998 by Martin Seligman and Mihaly Csikszentmihalyi: "We believe that a psychology of positive human functioning will arise, which achieves a scientific understanding and effective interventions to build thriving in...

 is sometimes brought up when addressing adolescent psychology as well. This approach towards adolescents refers to providing them with motivation to become socially acceptable and notable individuals, since many adolescents find themselves bored, indecisive and/or unmotivated.

Struggles with adolescent identity and depression usually set in when an adolescent experiences a loss. The most important loss in their lives is the changing relationship between the adolescent and their parents. Adolescents may also experience strife in their relationships with friends. This may be due to the activities their friends take part in, such as smoking, which causes adolescents to feel as though participating in such activities themselves is likely essential to maintaining these friendships. Teen depression
Depression (mood)
Depression is a state of low mood and aversion to activity that can affect a person's thoughts, behaviour, feelings and physical well-being. Depressed people may feel sad, anxious, empty, hopeless, helpless, worthless, guilty, irritable, or restless...

 can be extremely intense at times because of physical and hormonal changes but emotional instability is part of adolescence. Their changing mind, body and relationships often present themselves as stressful and that change, they assume, is something to be feared. Sleep deprivation has also been linked to adolescent depression, particularly in the teen years.

Views of family relationships during adolescence are changing. The old view of family relationships during adolescence put an emphasis on conflict and disengagement and thought storm and stress was normal and even inevitable. However, the new view puts emphasis on transformation or relationships and maintenance of connection.

Cognitive development


Biological changes in brain structure and connectivity within the brain interact with increased experience, knowledge, and changing social demands to produce rapid cognitive growth (see Changes in the brain above). The age at which particular changes take place will vary between individuals, but the changes discussed below generally begin at puberty or shortly thereafter and some skills continue to develop as the adolescent ages.

Theoretical perspectives


There are two perspectives on adolescent thinking. One is the constructivist view
Constructivism (learning theory)
Constructivism is a theory of knowledge that argues that humans generate knowledge and meaning from an interaction between their experiences and their ideas. During infancy, it was an interaction between human experiences and their reflexes or behavior-patterns. Piaget called these systems of...

 of cognitive development. Based on the work of Piaget
Jean Piaget
Jean Piaget was a French-speaking Swiss developmental psychologist and philosopher known for his epistemological studies with children. His theory of cognitive development and epistemological view are together called "genetic epistemology"....

, it takes a quantitative, state-theory approach, hypothesizing that adolescents’ cognitive improvement is relatively sudden and drastic. The second is the information-processing perspective, which derives from the study of artificial intelligence and attempts to explain cognitive development in terms of the growth of specific components of the thinking process.

Improvements in cognitive ability


By the time individuals have reached age 15 or so, their basic thinking abilities are comparable to those of adults. These improvements occur in five areas during adolescence:
  1. Attention. Improvements are seen in selective attention, the process by which one focuses on one stimulus while tuning out another. Divided attention
    Attention
    Attention is the cognitive process of paying attention to one aspect of the environment while ignoring others. Attention is one of the most intensely studied topics within psychology and cognitive neuroscience....

    , the ability to pay attention to two or more stimuli at the same time, also improves.
  2. Memory. Improvements are seen in both working memory
    Working memory
    Working memory has been defined as the system which actively holds information in the mind to do verbal and nonverbal tasks such as reasoning and comprehension, and to make it available for further information processing...

     and long-term memory
    Long-term memory
    Long-term memory is memory in which associations among items are stored, as part of the theory of a dual-store memory model. According to the theory, long term memory differs structurally and functionally from working memory or short-term memory, which ostensibly stores items for only around 20–30...

    .
  3. Processing speed. Adolescents think more quickly than children. Processing speed improves sharply between age five and middle adolescence; it then begins to level off at age 15 and does not appear to change between late adolescence and adulthood.
  4. Organization. Adolescents are more aware of their own thought processes and can use mnemonic devices and other strategies to think more efficiently.
  5. Metacognition
    Metacognition
    Metacognition is defined as "cognition about cognition", or "knowing about knowing." It can take many forms; it includes knowledge about when and how to use particular strategies for learning or for problem solving...

    .

Hypothetical/abstract thinking


Adolescents' thinking is less bound to concrete events than that of children: they can contemplate possibilities outside the realm of what currently exists. One manifestation of the adolescent’s increased facility with thinking about possibilities is the improvement of skill in deductive reasoning
Deductive reasoning
Deductive reasoning, also called deductive logic, is reasoning which constructs or evaluates deductive arguments. Deductive arguments are attempts to show that a conclusion necessarily follows from a set of premises or hypothesis...

, which leads to the development of hypothetical thinking. This provides the ability to plan ahead, see the future consequences of an action and to provide alternative explanations of events. It also makes adolescents more skilled debaters, as they can reason against a friend’s or parent’s assumptions. Adolescents also develop a more sophisticated understanding of probability.

The appearance of more systematic, abstract thinking is another notable aspect of cognitive development during adolescence. For example, adolescents find it easier than children to comprehend the sorts of higher-order abstract logic inherent in puns, proverbs, metaphors, and analogies. Their increased facility permits them to appreciate the ways in which language can be used to convey multiple messages, such as satire, metaphor, and sarcasm. (Children younger than age nine often cannot comprehend sarcasm at all). This also permits the application of advanced reasoning and logical processes to social and ideological matters such as interpersonal relationships, politics, philosophy, religion, morality, friendship, faith, democracy, fairness, and honesty.

Metacognition


A third gain in cognitive ability involves thinking about thinking itself, a process referred to as metacognition
Metacognition
Metacognition is defined as "cognition about cognition", or "knowing about knowing." It can take many forms; it includes knowledge about when and how to use particular strategies for learning or for problem solving...

. It often involves monitoring one’s own cognitive activity during the thinking process. Adolescents’ improvements in knowledge of their own thinking patterns lead to better self-control and more effective studying. It is also relevant in social cognition, resulting in increased introspection
Introspection
Introspection is the self-observation and reporting of conscious inner thoughts, desires and sensations. It is a conscious and purposive process relying on thinking, reasoning, and examining one's own thoughts, feelings, and, in more spiritual cases, one's soul...

, self-consciousness
Self-consciousness
Self-consciousness is an acute sense of self-awareness. It is a preoccupation with oneself, as opposed to the philosophical state of self-awareness, which is the awareness that one exists as an individual being; although some writers use both terms interchangeably or synonymously...

, and intellectualization (in the sense of thought about one’s own thoughts, rather than the Freudian definition as a defense mechanism). Adolescents are much better able than children to understand that people do not have complete control over their mental activity. Being able to introspect may lead to two forms of adolescent egocentrism, which results in two distinct problems in thinking: the imaginary audience
Imaginary audience
The imaginary audience refers to an egocentric state where an individual imagines and believes that multitudes of people are enthusiastically listening to him or her at all times...

 and the personal fable
Personal fable
The personal fable is a term coined by David Elkind that is used in psychology to describe a form of egocentrism normally exhibited during early adolescence, and it is characterized by an over-differentiating of one's experiences and feelings from others to the point of assuming those experiences...

. These likely peak at age fifteen, along with self-consciousness in general.

Related to metacognition
Metacognition
Metacognition is defined as "cognition about cognition", or "knowing about knowing." It can take many forms; it includes knowledge about when and how to use particular strategies for learning or for problem solving...

 and abstract thought
Abstraction
Abstraction is a process by which higher concepts are derived from the usage and classification of literal concepts, first principles, or other methods....

, perspective-taking involves a more sophisticated theory of mind
Theory of mind
Theory of mind is the ability to attribute mental states—beliefs, intents, desires, pretending, knowledge, etc.—to oneself and others and to understand that others have beliefs, desires and intentions that are different from one's own...

. Adolescents reach a stage of social perspective-taking in which they can understand how the thoughts or actions of one person can influence those of another person, even if they personally are not involved.

Relativistic thinking


Compared to children, adolescents are more likely to question others’ assertions, and less likely to accept facts as absolute truths. Through experience outside the family circle, they learn that rules they were taught as absolute are in fact relativistic. They begin to differentiate between rules instituted out of common sense—not touching a hot stove—and those that are based on culturally-relative standards (codes of etiquette, not dating until a certain age), a delineation that younger children do not make. This can lead to a period of questioning authority in all domains.

Wisdom


Wisdom, or the capacity for insight and judgment that is developed through experience, increases between the ages of fourteen and twenty-five, then levels off. Thus, it is during the adolescence-adulthood transition that individuals acquire the type of wisdom that is associated with age. Wisdom is not the same as intelligence: adolescents do not improve substantially on IQ tests since their scores are relative to others in their same age group, and relative standing usually does not change—everyone matures at approximately the same rate.

Risk-taking


In light of the fact that most injuries sustained by adolescents are related to risky behavior (car crashes, alcohol, unprotected sex), much research has been done on adolescent risk-taking, particularly on whether and why adolescents are more likely to take risks than adults. Behavioral decision-making theory says that adolescents and adults both weigh the potential rewards and consequences of an action. However, research has shown that adolescents seem to give more weight to rewards, particularly social rewards, than do adults.

During adolescence, there is an extremely high emphasis on approval of peers as a reward due to adolescents' increased self-consciousness. There may be evolutionary benefits to an increased propensity for risk-taking in adolescence—without risk-taking, teenagers would not have the motivation or confidence necessary to make the change in society from childhood to adulthood. It may also have reproductive advantages: adolescents have a newfound priority in sexual attraction and dating, and risk-taking is required to impress potential mates. Research also indicates that baseline sensation seeking
Sensation-Seeking Scale
Marvin Zuckerman of the University of Delaware has spent more than 20 years researching the personality trait he has come to call "sensation seeking." His work indicates that sensation-seeking is one of a handful of "core traits" that can be used to describe human personality...

 may affect risk-taking behavior throughout the lifespan.

Identity development


Among the most common beliefs about adolescence is that it is the time when teens form their personal identities. Empirical studies suggest that this process might be more accurately described as identity development, rather than formation, but confirms a normative process of change in both content and structure of one’s thoughts about the self. Researchers have used three general approaches to understanding identity development: self-concept, sense of identity, and self-esteem.

Self-concept



Early in adolescence, cognitive development
Cognitive development
Cognitive development is a field of study in neuroscience and psychology focusing on a child's development in terms of information processing, conceptual resources, perceptual skill, language learning, and other aspects of brain development and cognitive psychology compared to an adult's point of...

s result in greater self-awareness, greater awareness of others and their thoughts and judgments, the ability to think about abstract, future possibilities, and the ability to consider multiple possibilities at once. As a result, adolescents experience a significant shift from the simple, concrete, and global self-descriptions typical of young children.

Adolescents can now conceptualize multiple "possible selves" they could become and long-term possibilities and consequences of their choices. Exploring these possibilities may result in abrupt changes in self-presentation as the adolescent chooses or rejects qualities and behaviors, trying to guide the actual self toward the ideal self (who the adolescent wishes to be) and away from the feared self (who the adolescent does not want to be). For many, these distinctions are uncomfortable, but they also appear to motivate achievement through behavior consistent with the ideal and distinct from the feared possible selves.

Further distinctions in self-concept, called "differentiation," occur as the adolescent recognizes the contextual influences on their own behavior and the perceptions of others, and begin to qualify their traits when asked to describe themselves. Differentiation appears to be fully developed by mid-adolescence. Peaking in the 7th-9th grades, the personality traits adolescents use to describe themselves refer to specific contexts, and therefore may contradict one another. The recognition of inconsistent content in the self-concept is a common source of distress in these years (see Cognitive dissonance
Cognitive dissonance
Cognitive dissonance is a discomfort caused by holding conflicting ideas simultaneously. The theory of cognitive dissonance proposes that people have a motivational drive to reduce dissonance. They do this by changing their attitudes, beliefs, and actions. Dissonance is also reduced by justifying,...

), but this distress may benefit adolescents by encouraging structural development.

Differentiation results in organization and integration of the self-concept. The multifaceted self is understood to include several stable, if inconsistent, sets of traits applicable when the individual with different people and circumstances. This includes negative traits and weaknesses, which adolescents can now recognize and qualify: "consistent with this, adolescents who have more complex self-conceptions are less likely to be depressed." Moreover, although only true in some circumstances, differentiated traits are contrasted with “false-self behavior,” which is not representative of the “real” self. Recognition of the inauthentic indicates that the adolescent is gaining a sense of continuous, overlapping, coherent sense of identity.

Sense of identity


Unlike the conflicting aspects of self-concept, identity represents a coherent sense of self stable across circumstances and including past experiences and future goals. Everyone has a self-concept, whereas Erik Erikson
Erik Erikson
Erik Erikson was a Danish-German-American developmental psychologist and psychoanalyst known for his theory on social development of human beings. He may be most famous for coining the phrase identity crisis. His son, Kai T...

 argued that not everyone fully achieves identity. Erikson’s theory of stages of development
Erikson's stages of psychosocial development
Erikson's stages of psychosocial development as articulated by Erik Erikson explain eight stages through which a healthily developing human should pass from infancy to late adulthood. In each stage the person confronts, and hopefully masters, new challenges. Each stage builds on the successful...

 includes the identity crisis
Identity crisis
Identity crisis is an internal conflict of and search for identity.Identity crisis may also refer to:In comics:* Identity Crisis , DC Comics seven-issue limited series...

 in which adolescents must explore different possibilities and integrate different parts of themselves before committing to their beliefs. He described the resolution of this process as a stage of “identity achievement” (see Fig. 1) but also stressed that the identity challenge “is never fully resolved once and for all at one point in time.”

Researcher James Marcia developed the current method for testing an individual’s progress along these stages. His questions are divided into three categories: occupation, ideology, and interpersonal relationships. Answers are scored based on extent to which the individual has explored and the degree to which he has made commitments. The result is classification of the individual into a) Identity Diffusion in which all children begin, b) Identity Foreclosure in which commitments are made without the exploration of alternatives, c) Moratorium, or the process of exploration, or d) Identity Achievement in which Moratorium has occurred and resulted in commitments.

Research since reveals self-examination beginning early in adolescence, but identity achievement rarely occurring before age 18. The freshman year of college influences identity development significantly, but may actually prolong psychosocial moratorium by encouraging reexamination of previous commitments and further exploration of alternate possibilities without encouraging resolution. For the most part, evidence has supported Erikson’s stages: each correlates with the personality traits he originally predicted. Studies also confirm the impermanence of the stages there is no final endpoint in Identity Development.

Self-esteem


The final major aspect of identity formation is self-esteem
Self-esteem
Self-esteem is a term in psychology to reflect a person's overall evaluation or appraisal of his or her own worth. Self-esteem encompasses beliefs and emotions such as triumph, despair, pride and shame: some would distinguish how 'the self-concept is what we think about the self; self-esteem, the...

, one’s thoughts and feelings about one’s self-concept and identity. Contrary to popular belief, there is no empirical evidence for a significant drop in self-esteem over the course of adolescence. ‘Barometric self-esteem’ fluctuates rapidly and can cause severe distress and anxiety, but baseline self-esteem remains highly stable across adolescence. The validity of global self-esteem scales has been questioned, and many suggest that more specific scales might reveal more about the adolescent experience. It is also important to note that the patterns of change in self-esteem differ significantly by gender.

Family


Adolescence marks a rapid change in one’s role within a family. Young children tend to assert themselves forcefully, but are unable to demonstrate much influence over family decisions until early adolescence, when they are increasingly viewed by parents as equals. When children go through puberty, there is often a significant increase in parent-child conflict and a less cohesive familial bond. Arguments often concern minor issues of control, such as curfew and acceptable clothing, which adolescents may have previously viewed as issues over which their parents had complete authority. Parent-adolescent disagreement also increases as friends demonstrate a greater impact on one another, new influences on the adolescent that may be in opposition to parents’ values.

During childhood, siblings are a source of conflict and frustration as well as a support system. Adolescence may affect this relationship differently, depending on sibling gender. In same-sex sibling pairs, intimacy peaks during early adolescence, then steadily declines. Mixed-sex siblings pairs act in the opposite way; siblings drift apart during early adolescent years, but experience an increase in intimacy starting at middle adolescence. Sustaining positive sibling relations can assist adolescents in a number of ways. Siblings are able to act as peers, and may increase one another's sociability and feelings of self-worth. Older siblings can give guidance to younger siblings, although the impact of this can be either positive or negative depending on the activity of the older sibling.

Peers


Peer group
Peer group
A peer group is a social group consisting of humans. Peer groups are an informal primary group of people who share a similar or equal status and who are usually of roughly the same age, tended to travel around and interact within the social aggregate Members of a particular peer group often have...

s are especially important during adolescence, a period of development characterized by a dramatic increase in time spent with peers and a decrease in adult supervision. Adolescents also associate with friends of the opposite sex much more than in childhood and tend to identify with larger groups of peers based on shared characteristics.

During early adolescence, adolescents often associate in cliques, exclusive, single-sex groups of peers with whom they are particularly close. Towards late adolescence, cliques often merge into mixed-sex groups as teenagers begin romantically engaging with one another.Typically, in schools, the most popular boys would participate in achievement-oriented activities, which were highly competitive and aggressive such as, athletics. Likewise, the most popular girls would participate in the most interesting social activities, ranging from skiing to late-night parties. Of course, girls who engaged in these activities had to be physically attractive to compete for the opposite sex's attention. Thus, it became common to attribute competitiveness to boys and attractiveness with girls in clique groups. These small friend groups break down even further as socialization becomes more couple-oriented. Despite the common notion that cliques are an inherently negative influence, they may help adolescents become socially acclimated and form a stronger sense of identity.

On a larger scale, adolescents often associate with crowds, groups of individuals who share a common interest or activity. Often, crowd identities may be the basis for stereotyping young people, categorizing them as jocks, nerd
Nerd
Nerd is a derogatory slang term for an intelligent but socially awkward and obsessive person who spends time on unpopular or obscure pursuits, to the exclusion of more mainstream activities. Nerds are considered to be awkward, shy, and unattractive...

s, and so on. In large, multi-ethnic high schools, there are often ethnically-determined crowds as well. While crowds are very influential during early and middle adolescence, they lose salience during high school as students identify more individually.

While peers may facilitate social development for one another, they may also hinder it. Both physical
Assault
In law, assault is a crime causing a victim to fear violence. The term is often confused with battery, which involves physical contact. The specific meaning of assault varies between countries, but can refer to an act that causes another to apprehend immediate and personal violence, or in the more...

 and relational
Relational aggression
Relational aggression, also known as covert aggression or covert bullying, is a type of aggression in which harm is caused through damage to relationships or social status within a group rather than by means of actual or threatened physical violence...

 aggression are linked to a vast number of enduring psychological difficulties, especially depression, as is social rejection
Social rejection
Social rejection occurs when an individual is deliberately excluded from a social relationship or social interaction. The topic includes both interpersonal rejection and romantic rejection. A person can be rejected on an individual basis or by an entire group of people...

. Because of this, bullied adolescents often develop problems that lead to further victimization.

Romance and sexual activity



Romantic relationships
Intimate relationship
An intimate relationship is a particularly close interpersonal relationship that involves physical or emotional intimacy. Physical intimacy is characterized by romantic or passionate love and attachment, or sexual activity. The term is also sometimes used euphemistically for a sexual...

 tend to increase in prevalence throughout adolescence. By age 15, 53% of adolescents have had a romantic relationship that lasted at least one month over the course of the previous 18 months. The typical duration of relationships increases throughout the teenage years as well. This constant increase in the likelihood of a long-term relationship can be explained by sexual maturation
Sexual maturity
Sexual maturity is the age or stage when an organism can reproduce. It is sometimes considered synonymous with adulthood, though the two are distinct...

 and the development of cognitive skills necessary to maintain a romantic bond (e.g. caregiving, appropriate attachment), although these skills are not strongly developed until late adolescence. Long-term relationships allow adolescents to gain the skills necessary for high-quality relationships later in life and develop feelings of self-worth. Overall, positive romantic relationships among adolescents can result in long-term benefits. High-quality romantic relationships are associated with higher commitment in early adulthood. and are positively associated with self-esteem, self-confidence, and social competence.

Adolescents often date within their demographic in regards to race, ethnicity, popularity, and physical attractiveness. However, there are traits in which certain individuals, particularly adolescent girls, seek diversity. While most adolescents date people approximately their own age, boys typically date partners the same age or younger; girls typically date partners the same age or older.

Dating violence
Dating abuse
Dating abuse or dating violence is defined as the perpetration or threat of an act of violence by at least one member of an unmarried couple on the other member within the context of dating or courtship. It is also when one partner tries to maintain power and control over the other through...

 is fairly prevalent within adolescent relationships. When surveyed, 10-45% of adolescents reported having experiencing physical violence in the context of a relationship while one-third to a quarter of adolescents reported having experiencing psychological aggression. This reported aggression includes hitting, throwing things, or slaps, although most of this physical aggression does not result in a medical visit. Physical aggression in relationships tends to decline from high school through college and young adulthood. By their early twenties, many fewer romantic couple engage in physical aggression, and aggressors tend to be much more deviant. In heterosexual couples, there is no significant difference between the rates of male and female aggressors, a surprising finding considering the common assumption that males are more aggressive overall. Despite these jarring statistics, nurturant parenting style
Nurturant parent model
The nurturant parent model is a parenting style which envisions a family model where children are expected to explore their surroundings with protection from their parents. This model believes that children inherently know what they need and should be allowed to explore...

 is associated with lower rates of relationship violence.

Adolescence marks a time of sexual maturation, which manifests in social interactions as well. While adolescents may engage in casual sexual encounters
Casual sex
Casual sex or hooking up refers to certain types of human sexual activity outside the context of a romantic relationship. The term is not always used consistently: some use it to refer to any extramarital sex, some use it to refer to sex in a casual relationship, whereas others reserve its use for...

 (often referred to as hookups), most sexual experience during this period of development takes place within romantic relationships. Kissing, hand holding, and hugging signify satisfaction and commitment. Among young adolescents, "heavy" sexual activity, marked by genital stimulation, is often associated with violence, depression, and poor relationship quality. This effect does not hold true for sexual activity in late adolescence that takes place within a romantic relationship.

Adolescent sexuality refers to sexual feelings, behavior and development in adolescents and is a stage of human sexuality. Sexuality and sexual desire usually begins to intensify along with the onset of puberty
Puberty
Puberty is the process of physical changes by which a child's body matures into an adult body capable of reproduction, as initiated by hormonal signals from the brain to the gonads; the ovaries in a girl, the testes in a boy...

. The expression of sexual desire among adolescents (or anyone, for that matter), might be influenced by family values and the culture and religion they have grown up in (or as a backlash to such), social engineering
Social engineering (political science)
Social engineering is a discipline in political science that refers to efforts to influence popular attitudes and social behaviors on a large scale, whether by governments or private groups. In the political arena, the counterpart of social engineering is political engineering.For various reasons,...

, social control
Social control
Social control refers generally to societal and political mechanisms or processes that regulate individual and group behavior, leading to conformity and compliance to the rules of a given society, state, or social group. Many mechanisms of social control are cross-cultural, if only in the control...

, taboos, and other kinds of social mores.

In contemporary society, adolescents also face some risks as their sexuality begins to transform. Whilst some of these such as emotional distress (fear of abuse or exploitation) and sexually transmitted disease
Sexually transmitted disease
Sexually transmitted disease , also known as a sexually transmitted infection or venereal disease , is an illness that has a significant probability of transmission between humans by means of human sexual behavior, including vaginal intercourse, oral sex, and anal sex...

s (including HIV
HIV
Human immunodeficiency virus is a lentivirus that causes acquired immunodeficiency syndrome , a condition in humans in which progressive failure of the immune system allows life-threatening opportunistic infections and cancers to thrive...

/AIDS
AIDS
Acquired immune deficiency syndrome or acquired immunodeficiency syndrome is a disease of the human immune system caused by the human immunodeficiency virus...

) are not necessarily inherent to adolescence, others such as pregnancy
Teenage pregnancy
Teenage pregnancy is a pregnancy of a female under the age of 20 when the pregnancy ends. It generally refers to a female who is unmarried and usually refers to an unplanned pregnancy...

 (through non-use or failure of contraceptives) are seen as social problems in most western societies. In terms of sexual identity
Sexual identity
Sexual identity is a term that, like sex, has two distinctively different meanings. One describes an identity roughly based on sexual orientation, the other an identity based on sexual characteristics, which is not socially based but based on biology, a concept related to, but different from,...

, while all sexual orientation
Sexual orientation
Sexual orientation describes a pattern of emotional, romantic, or sexual attractions to the opposite sex, the same sex, both, or neither, and the genders that accompany them. By the convention of organized researchers, these attractions are subsumed under heterosexuality, homosexuality,...

s found in adults are also represented among adolescents, statistically the suicide rate amongst LGBT
LGBT
LGBT is an initialism that collectively refers to "lesbian, gay, bisexual, and transgender" people. In use since the 1990s, the term "LGBT" is an adaptation of the initialism "LGB", which itself started replacing the phrase "gay community" beginning in the mid-to-late 1980s, which many within the...

 adolescents is up to four times higher than that of their heterosexual peers.

According to anthropologist Margaret Mead
Margaret Mead
Margaret Mead was an American cultural anthropologist, who was frequently a featured writer and speaker in the mass media throughout the 1960s and 1970s....

 and psychologist Albert Bandura
Albert Bandura
Albert Bandura is a psychologist and the David Starr Jordan Professor Emeritus of Social Science in Psychology at Stanford University...

, the turmoil found in adolescence in Western society has a cultural rather than a physical cause; they reported that societies where young women engaged in free sexual activity had no such adolescent turmoil.

In a 2008 study conducted by YouGov
YouGov
YouGov, formerly known as PollingPoint in the United States, is an international internet-based market research firm launched in the UK in May 2000 by Stephan Shakespeare, now Chief Executive Officer, and Nadhim Zahawi...

 for Channel 4
Channel 4
Channel 4 is a British public-service television broadcaster which began working on 2 November 1982. Although largely commercially self-funded, it is ultimately publicly owned; originally a subsidiary of the Independent Broadcasting Authority , the station is now owned and operated by the Channel...

, 20% of 14−17-year-olds surveyed revealed that they had their first sexual experience at 13 or under in the United Kingdom. A 2002 American study found that those aged 15–44 reported that the average age of first sexual intercourse was 17.0 for males and 17.3 for females.

The age of consent
Age of consent
While the phrase age of consent typically does not appear in legal statutes, when used in relation to sexual activity, the age of consent is the minimum age at which a person is considered to be legally competent to consent to sexual acts. The European Union calls it the legal age for sexual...

 to sexual activity varies widely among international jurisdictions, ranging from 12 to 21 years.

Culture


In commerce this generation (21st century adolescence) is seen as an important target. Mobile phones, electronic devices such as the iPod
IPod
iPod is a line of portable media players created and marketed by Apple Inc. The product line-up currently consists of the hard drive-based iPod Classic, the touchscreen iPod Touch, the compact iPod Nano, and the ultra-compact iPod Shuffle...

, contemporary popular music
Popular music
Popular music belongs to any of a number of musical genres "having wide appeal" and is typically distributed to large audiences through the music industry. It stands in contrast to both art music and traditional music, which are typically disseminated academically or orally to smaller, local...

, movies
Film
A film, also called a movie or motion picture, is a series of still or moving images. It is produced by recording photographic images with cameras, or by creating images using animation techniques or visual effects...

, television
Television
Television is a telecommunication medium for transmitting and receiving moving images that can be monochrome or colored, with accompanying sound...

 programs, website
Website
A website, also written as Web site, web site, or simply site, is a collection of related web pages containing images, videos or other digital assets. A website is hosted on at least one web server, accessible via a network such as the Internet or a private local area network through an Internet...

s, sport
Sport
A Sport is all forms of physical activity which, through casual or organised participation, aim to use, maintain or improve physical fitness and provide entertainment to participants. Sport may be competitive, where a winner or winners can be identified by objective means, and may require a degree...

s, video games and clothes are heavily marketed and often popular amongst adolescents.

In the past (and still in some cultures) there were ceremonies that celebrated adulthood, typically occurring during adolescence. Seijin shiki
Seijin shiki
is a Japanese holiday held annually on the second Monday of January. It is held in order to congratulate and encourage all those who have reached the age of majority over the past year, and to help them realize that they have become adults...

(literally "adult ceremony") is a Japanese example of this. Upanayanam
Upanayanam
Upanayana is the initiation ritual by which initiates are invested with a sacred thread, to symbolize the transference of spiritual knowledge .- Significance of the sacred thread :...

 is a coming of age ceremony for males in the Hindu
Hinduism
Hinduism is the predominant and indigenous religious tradition of the Indian Subcontinent. Hinduism is known to its followers as , amongst many other expressions...

 world. In Judaism
Judaism
Judaism ) is the "religion, philosophy, and way of life" of the Jewish people...

, 13-year-old boys and 12-year-old girls become Bar or Bat Mitzvah, respectively, and often have a celebration to mark this coming of age. Among some denominations of Christianity
Christianity
Christianity is a monotheistic religion based on the life and teachings of Jesus as presented in canonical gospels and other New Testament writings...

, the rite
Rite
A rite is an established, ceremonious, usually religious act. Rites in this sense fall into three major categories:* rites of passage, generally changing an individual's social status, such as marriage, baptism, or graduation....

 or sacrament
Sacrament
A sacrament is a sacred rite recognized as of particular importance and significance. There are various views on the existence and meaning of such rites.-General definitions and terms:...

 of Confirmation is received by adolescents and may be considered the time at which adolescents become members of the church in their own right (there is also a Confirmation ceremony in some Reform Jewish
Reform Judaism
Reform Judaism refers to various beliefs, practices and organizations associated with the Reform Jewish movement in North America, the United Kingdom and elsewhere. In general, it maintains that Judaism and Jewish traditions should be modernized and should be compatible with participation in the...

 temples, although the bar or bat mitzvah ceremony appears to have precedence). In United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...

, girls will often have a "sweet sixteen
Sweet sixteen (birthday)
A sweet sixteen party is a type of birthday party in the United States celebrating a sixteenth birthday, Sweet sixteen parties mark a coming of age.- Types of sweet sixteen party :...

" party to celebrate turning the aforementioned age, a tradition similar to the quinceañera
Quinceañera
Quinceañera , sometimes called "Fiesta de quince años", "Fiesta de Quinceañera", "Quince años" or simply "quince", is the celebration of a girl's fifteenth birthday in parts of Latin America and elsewhere in communities of immigrants from Latin America...

 in Latin
Latin
Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...

 culture. In modern western society, events such as getting your first driver's license, high school and later on college graduation and first career related job are thought of as being more significant markers in transition to adulthood.

Adolescents have also been an important factor in many movements for positive social change around the world. The popular history of adolescents participating in these movements may perhaps start with Joan of Arc, and extend to present times with popular youth activism
Youth activism
Youth activism is when the youth voice is engaged in community organizing for social change. Around the world, young people are engaged in activism as planners, researchers, teachers, evaluators, social workers, decision-makers, advocates and leading actors in the environmental movement, social...

, student activism
Student activism
Student activism is work done by students to effect political, environmental, economic, or social change. It has often focused on making changes in schools, such as increasing student influence over curriculum or improving educational funding...

, and other efforts to make the youth voice
Youth voice
Youth voice refers to the distinct ideas, opinions, attitudes, knowledge, and actions of young people as a collective body. The term youth voice often groups together a diversity of perspectives and experiences, regardless of backgrounds, identities, and cultural differences...

 heard.

Cultural differences


The definition and development of adolescents varies widely by generation, country, culture and socio-economic standing. One of the most varied differences is the length of the transition period between childhood and adulthood (one way of defining adolescence). While in some countries, such as the United States, adolescence can last nearly a decade, in others the transition—often in the form of a ceremony—can last for only a few days. There are also varied forms of transition. In the US, while there are no marked ceremonies, there are popular social and religious traditions that tend to mark this transition, such as Bar Mtizvahs, Quinceañera
Quinceañera
Quinceañera , sometimes called "Fiesta de quince años", "Fiesta de Quinceañera", "Quince años" or simply "quince", is the celebration of a girl's fifteenth birthday in parts of Latin America and elsewhere in communities of immigrants from Latin America...

s, cotillions, and debutant balls
Debutante
A débutante is a young lady from an aristocratic or upper class family who has reached the age of maturity, and as a new adult, is introduced to society at a formal "début" presentation. It should not be confused with a Debs...

. In other countries, initiation ceremonies play an important role, marking the transition into adulthood or the entrance into adolescence. The transition is usually accompanied by obvious physical changes, which can vary from a change in clothing to tattoos and scarification.

Social role transitions


This transition period can also be linked to the passage from schools to work. Many countries, such as Germany, have implemented programs early in schools to help teens "apprentice" while in high school, so that can be ready to enter the workforce at a relatively high and secure level. In the United States, it is widely accepted that college is the primary option adolescents have in order to find training for a successful career, leaving many adolescents for whom college is not a viable option out of the competitive career market.

Sexuality


There are many cultural and socio-economic differences which influence how adolescents' sexuality develops. Menarche
Menarche
Menarche is the first menstrual cycle, or first menstrual bleeding, in female human beings. From both social and medical perspectives it is often considered the central event of female puberty, as it signals the possibility of fertility....

 (the first menstrual period of a female-bodied person’s life) is, for many cultures, the defining point for the beginning of a transition into adulthood. The age of menarche varies form culture to culture. Girls from countries where menarche/menstruation is seen as an important event, or where there is an ambivalence towards it, tend to have more negative opinions about it.

An adolescent’s sexual socialization is highly dependent upon the society they live in, and how restrictive or permissive that society is when it comes to sexual activity. Highly restrictive societies tend to prohibit and highly regulate all forms of contact between genders that could lead to sexual contact. The United States is considered semi-restrictive because, while sex is prevalent in the media and a substantial number of teenagers are sexually active, there are restrictions on the amount of sexual exploration and expression teens can engage in openly. There are many sexually permissive societies, such as the Pukapukans
Puka-Puka
Puka-Puka is a small coral atoll in the north-eastern Tuamotu Archipelago, sometimes included as a member of the Disappointment Islands. This atoll is quite isolated, the nearest land being Fakahina, located 182 km to the southwest....

 of Polynesia and the Trobrianders
Trobriand Islands
The Trobriand Islands are a 450 km² archipelago of coral atolls off the eastern coast of New Guinea. They are situated in Milne Bay Province in Papua New Guinea. Most of the population of 12,000 indigenous inhabitants live on the main island of Kiriwina, which is also the location of the...

, who allow and encourage their children and teens to openly explore their sexuality.

Autonomy


Recognition of autonomy
Autonomy
Autonomy is a concept found in moral, political and bioethical philosophy. Within these contexts, it is the capacity of a rational individual to make an informed, un-coerced decision...

 and the age at which an adolescent is deemed responsible enough to make their own decisions is determined by the expectations of parents, society, and peers. These age-associated expectations vary by culture and ethnicity. White adolescents tend to expect to be granted autonomy at a younger age. Gender and birth order do not affect the age at which autonomy is granted, except in Black American households, where boys are generally granted more freedom than girls. Conflict over autonomy is best avoided when teens and parents agree on age expectations for autonomy. This presents a problem for immigrant families in which the parents come from a culture in which autonomy is granted later than it is in the society to which they have emigrated. In these cases, adolescents are more likely to acculturate and will have different expectations for autonomy than their parents are comfortable granting.

Leisure time


American teenagers spend more time on leisure than many other countries. The average American adolescent spends about five hours a week on homework, while Indian, Taiwanese, and Japanese students spend an average of five hours a day. This is most likely due to the amount of emphasis and pressure that is placed on adolescents’ education in those countries. Americans tend to spend more time playing sports, socializing, caring for their appearance, and working after-school jobs (an American phenomenon). Differences in how American teens use their leisure time tend to be influenced by their amount of involvement in various activities rather than ethnicity or socioeconomic background. Busier, more well-rounded teens tend to be better-adjusted and more goal-oriented than their peers who engage in only one activity (such as sports) or none.

Legal issues, rights and privileges


Internationally, those who reach a certain age (often 18, though this varies) are legally considered to have reached the age of majority
Age of majority
The age of majority is the threshold of adulthood as it is conceptualized in law. It is the chronological moment when minors cease to legally be considered children and assume control over their persons, actions, and decisions, thereby terminating the legal control and legal responsibilities of...

 and are regarded as adults and are held to be responsible for their actions. People below this age are considered minors
Minor (law)
In law, a minor is a person under a certain age — the age of majority — which legally demarcates childhood from adulthood; the age depends upon jurisdiction and application, but is typically 18...

 or child
Child
Biologically, a child is generally a human between the stages of birth and puberty. Some vernacular definitions of a child include the fetus, as being an unborn child. The legal definition of "child" generally refers to a minor, otherwise known as a person younger than the age of majority...

ren. A person below the age of majority may gain adult rights through legal emancipation
Emancipation of minors
An emancipated minor is a minor who is allowed to conduct a business or any other occupation on their own behalf or for their own account outside the influence of a parent or guardian. The minor will then have full contractual capacity to conclude contract with regard to the business. Whether...

.

Those who are under the age of consent, or legal responsibility, may be considered too young to be held accountable for criminal action
Crime
Crime is the breach of rules or laws for which some governing authority can ultimately prescribe a conviction...

. This is called doli incapax or the defense of infancy
Defense of infancy
The defense of infancy is a form of defense known as an excuse so that defendants falling within the definition of an "infant" are excluded from criminal liability for their actions, if at the relevant time, they had not reached an age of criminal responsibility...

. The age of criminal responsibility varies from 7 in India
India
India , officially the Republic of India , is a country in South Asia. It is the seventh-largest country by geographical area, the second-most populous country with over 1.2 billion people, and the most populous democracy in the world...

 to 18 in Belgium
Belgium
Belgium , officially the Kingdom of Belgium, is a federal state in Western Europe. It is a founding member of the European Union and hosts the EU's headquarters, and those of several other major international organisations such as NATO.Belgium is also a member of, or affiliated to, many...

. After reaching the initial age, there may be levels of responsibility dictated by age and type of offense, and crimes committed by minors may be tried in a juvenile court
Juvenile court
A juvenile court is a tribunal having special authority to try and pass judgments for crimes committed by children or adolescents who have not attained the age of majority...

.

The legal working age
Legal working age
The legal working age is the minimum age required by law for a person to work, in each country or jurisdiction.Some types of labor are commonly prohibited even for those above the working age, if they have not reached yet the age of majority. Activities that are dangerous, harmful to the health or...

 in Western countries is usually 14 to 16, depending on the number of hours and type of employment. In the United Kingdom
United Kingdom
The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...

 and Canada, for example, young people between 14 and 16 can work at certain types of light work with some restrictions to allow for schooling; while youths over 16 can work full-time (excluding night work). Many countries also specify a minimum school leaving age
School leaving age
The school leaving age states the minimum age person is legally allowed to leave compulsory education...

, ranging from 10 to 18, at which a person is legally allowed to leave compulsory education
Compulsory education
Compulsory education refers to a period of education that is required of all persons.-Antiquity to Medieval Era:Although Plato's The Republic is credited with having popularized the concept of compulsory education in Western intellectual thought, every parent in Judea since Moses's Covenant with...

.

The age of consent
Age of consent
While the phrase age of consent typically does not appear in legal statutes, when used in relation to sexual activity, the age of consent is the minimum age at which a person is considered to be legally competent to consent to sexual acts. The European Union calls it the legal age for sexual...

 to sexual activity varies widely between jurisdictions, ranging from 13 to 21 years, the average age is 16. Sexual intercourse with a person below the local age of consent is usually treated as the crime of statutory rape
Statutory rape
The phrase statutory rape is a term used in some legal jurisdictions to describe sexual activities where one participant is below the age required to legally consent to the behavior...

. Some jurisdictions allow an exemption where both partners are close in age; for example, a 16-year-old and an 18-year-old. The age at which people are allowed to marry
Marriageable age
Marriageable age is the age at which a person is allowed to marry, either as of right or subject to parental or other forms of consent. The age and other requirements vary between countries, but generally it is set at 18, although most jurisdictions allow marriage at slightly younger ages with...

 also varies, from 17 in Yemen
Yemen
The Republic of Yemen , commonly known as Yemen , is a country located in the Middle East, occupying the southwestern to southern end of the Arabian Peninsula. It is bordered by Saudi Arabia to the north, the Red Sea to the west, and Oman to the east....

 to 22 for males and 20 for females in China
China
Chinese civilization may refer to:* China for more general discussion of the country.* Chinese culture* Greater China, the transnational community of ethnic Chinese.* History of China* Sinosphere, the area historically affected by Chinese culture...

. In Western countries, people are typically allowed to marry at 18, although they are sometimes allowed to marry at a younger age with parental or court consent. In developing countries, the legal marriageable age does not always correspond with the age at which people actually marry; for example, the legal age for marriage in Ethiopia
Ethiopia
Ethiopia , officially known as the Federal Democratic Republic of Ethiopia, is a country located in the Horn of Africa. It is the second-most populous nation in Africa, with over 82 million inhabitants, and the tenth-largest by area, occupying 1,100,000 km2...

 is 18 for both males and females, but in rural areas most girls are married by age 16.

In most democratic countries, a citizen is eligible to vote
Voting age
A voting age is a minimum age established by law that a person must attain to be eligible to vote in a public election.The vast majority of countries in the world have established a voting age. Most governments consider that those of any age lower than the chosen threshold lack the necessary...

 at 18. For example, in the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...

, the Twenty-sixth amendment
Twenty-sixth Amendment to the United States Constitution
The Twenty-sixth Amendment to the United States Constitution limited the minimum voting age to no more than 18. It was adopted in response to student activism against the Vietnam War and to partially overrule the Supreme Court's decision in Oregon v. Mitchell...

 decreased the voting age from 21 to 18. In a minority of countries, the voting age is 17 (for example, Indonesia
Indonesia
Indonesia , officially the Republic of Indonesia , is a country in Southeast Asia and Oceania. Indonesia is an archipelago comprising approximately 13,000 islands. It has 33 provinces with over 238 million people, and is the world's fourth most populous country. Indonesia is a republic, with an...

) or 16 (for example, Brazil
Brazil
Brazil , officially the Federative Republic of Brazil , is the largest country in South America. It is the world's fifth largest country, both by geographical area and by population with over 192 million people...

). By contrast, some countries have a minimum voting age of 21 (for example, Singapore
Singapore
Singapore , officially the Republic of Singapore, is a Southeast Asian city-state off the southern tip of the Malay Peninsula, north of the equator. An island country made up of 63 islands, it is separated from Malaysia by the Straits of Johor to its north and from Indonesia's Riau Islands by the...

) whereas the minimum age in Uzbekistan
Uzbekistan
Uzbekistan , officially the Republic of Uzbekistan is a doubly landlocked country in Central Asia and one of the six independent Turkic states. It shares borders with Kazakhstan to the west and to the north, Kyrgyzstan and Tajikistan to the east, and Afghanistan and Turkmenistan to the south....

 is 25. Age of candidacy
Age of candidacy
Age of candidacy is the minimum age at which a person can legally qualify to hold certain elected government offices. In many cases, it also determines the age at which a person may be eligible to stand for an election or be granted ballot access....

 is the minimum age at which a person can legally qualify to hold certain elected government offices. In most countries, a person must be 18 or over to stand for elected office, but some countries such as the United States and Italy
Italy
Italy , officially the Italian Republic languages]] under the European Charter for Regional or Minority Languages. In each of these, Italy's official name is as follows:;;;;;;;;), is a unitary parliamentary republic in South-Central Europe. To the north it borders France, Switzerland, Austria and...

 have further restrictions depending on the type of office.

The sale of selected items such as cigarette
Cigarette
A cigarette is a small roll of finely cut tobacco leaves wrapped in a cylinder of thin paper for smoking. The cigarette is ignited at one end and allowed to smoulder; its smoke is inhaled from the other end, which is held in or to the mouth and in some cases a cigarette holder may be used as well...

s, alcohol
Alcoholic beverage
An alcoholic beverage is a drink containing ethanol, commonly known as alcohol. Alcoholic beverages are divided into three general classes: beers, wines, and spirits. They are legally consumed in most countries, and over 100 countries have laws regulating their production, sale, and consumption...

, and video
Video
Video is the technology of electronically capturing, recording, processing, storing, transmitting, and reconstructing a sequence of still images representing scenes in motion.- History :...

s with violent or pornographic content is also restricted by age in most countries. In the U.S, the minimum age to buy an R-rated movie, M-rated game or an album with a parental advisory label is 17 (in some states, the age is 18 or even 21). In practice, it is common that young people engage in underage smoking
Tobacco smoking
Tobacco smoking is the practice where tobacco is burned and the resulting smoke is inhaled. The practice may have begun as early as 5000–3000 BCE. Tobacco was introduced to Eurasia in the late 16th century where it followed common trade routes...

 or drinking
Drinking
Drinking is the act of consuming water or a beverage through the mouth. Water is required for many of life’s physiological processes. Both excessive and inadequate water intake are associated with health problems.-Physiology:...

, and in some cultures this is tolerated to a certain degree. In the United States, teenagers are allowed to drive between 14–18 (each state sets its own minimum driving age of which a curfew
Curfew
A curfew is an order specifying a time after which certain regulations apply. Examples:# An order by a government for certain persons to return home daily before a certain time...

 may be imposed), in the US, adolescents 17 years of age can serve in the military. In Europe
Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...

 it is more common for the driving age to be higher (usually 18) while the drinking age is lower than that of the US (usually 16 or 18). In Canada
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...

, the drinking age is 18 in some areas and 19 in other areas. In Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...

, universally, the minimum drinking age is 18, unless a person is in a private residence or is under parental supervision in a licensed premises. The driving age varies from state to state but the more common system is a graduated system of "L plates" (a learning license that requires supervision from a licensed driver) from age 16, red "P plates" (probationary license) at 17, green "P plates" at 18 and finally a full license, i.e. for most people around the age of 20.

The legal gambling age also depends on the jurisdiction, although it is typically 18.

The minimum age for donating blood in the U.S is 17 although it may be 16 with parental permission in some states such as New York, New Jersey
New Jersey
New Jersey is a state in the Northeastern and Middle Atlantic regions of the United States. , its population was 8,791,894. It is bordered on the north and east by the state of New York, on the southeast and south by the Atlantic Ocean, on the west by Pennsylvania and on the southwest by Delaware...

, Wisconsin
Wisconsin
Wisconsin is a U.S. state located in the north-central United States and is part of the Midwest. It is bordered by Minnesota to the west, Iowa to the southwest, Illinois to the south, Lake Michigan to the east, Michigan to the northeast, and Lake Superior to the north. Wisconsin's capital is...

, and Pennsylvania.
Suitable age and discretion
Suitable age and discretion
Suitable age and discretion is both a legal definition of maturity, and an alternate method of service of process by which a process server can leave a summons, subpoena, or complaint with a person living at the residence of the defendant.-Minimum age:...

 is a legal
Common law
Common law is law developed by judges through decisions of courts and similar tribunals rather than through legislative statutes or executive branch action...

 definition of maturity
Maturity (psychological)
Maturity is a psychological term used to indicate how a person responds to the circumstances or environment in an appropriate manner. This response is generally learned rather than instinctive, and is not determined by one's age...

.

A number of social scientists, including anthropologist Margaret Mead
Margaret Mead
Margaret Mead was an American cultural anthropologist, who was frequently a featured writer and speaker in the mass media throughout the 1960s and 1970s....

 and sociologist Mike Males, have noted the contradictory treatment of laws affecting adolescents in the United States. As Males has noted, the US Supreme Court has, "explicitly ruled that policy-makers may impose adult responsibilities and punishments on individual youths as if they were adults at the same time laws and policies abrogate adolescents’ rights en masse as if they were children."

The issue of youth activism
Youth activism
Youth activism is when the youth voice is engaged in community organizing for social change. Around the world, young people are engaged in activism as planners, researchers, teachers, evaluators, social workers, decision-makers, advocates and leading actors in the environmental movement, social...

 affecting political, social, educational, and moral circumstances is of growing significance around the world. Youth-led organizations around the world have fought for social justice
Social justice
Social justice generally refers to the idea of creating a society or institution that is based on the principles of equality and solidarity, that understands and values human rights, and that recognizes the dignity of every human being. The term and modern concept of "social justice" was coined by...

, the youth vote
Youth vote
The youth vote is a political term used primarily in the United States to describe 18 to 29-year-olds and their voting habits.The term "Youth Vote" goes back to the 1930s, when low-income rural and urban young people in the United States were first mobilized to vote in blocs by the youth activism...

 seeking to gain teenagers the right to vote, to secure more youth rights
Youth rights
Youth rights refers to a set of philosophies intended to enhance civil rights for young people. They are a response to the oppression of young people, with advocates challenging ephebiphobia, adultism and ageism through youth participation, youth/adult partnerships, and promoting, ultimately,...

, and demanding better schools through student activism
Student activism
Student activism is work done by students to effect political, environmental, economic, or social change. It has often focused on making changes in schools, such as increasing student influence over curriculum or improving educational funding...

.

Since the advent of the Convention on the Rights of the Child
Convention on the Rights of the Child
The United Nations Convention on the Rights of the Child is a human rights treaty setting out the civil, political, economic, social, health and cultural rights of children...

 in 1989 (children defined as under 18), almost every country (except the U.S. & Somalia
Somalia
Somalia , officially the Somali Republic and formerly known as the Somali Democratic Republic under Socialist rule, is a country located in the Horn of Africa. Since the outbreak of the Somali Civil War in 1991 there has been no central government control over most of the country's territory...

) in the world has become voluntarily legally committed to advancing an anti-discriminatory stance towards young people of all ages. This is a legally binding document which secures youth participation
Youth participation
Youth participation is the active engagement of young people throughout their communities. It is often used as a short-hand for youth participation in any many forms, including decision-making, sports, schools and any activity where young people are not historically engaged.-Coinage:Youth...

 throughout society while acting against unchecked child labor
Child labor
Child labour refers to the employment of children at regular and sustained labour. This practice is considered exploitative by many international organizations and is illegal in many countries...

, child soldiers, child prostitution, and pornography
Pornography
Pornography or porn is the explicit portrayal of sexual subject matter for the purposes of sexual arousal and erotic satisfaction.Pornography may use any of a variety of media, ranging from books, magazines, postcards, photos, sculpture, drawing, painting, animation, sound recording, film, video,...

.

See also


  • Adolescent medicine
    Adolescent medicine
    Adolescent medicine is a medical subspecialty that focuses on care of patients who are in the adolescent period of development, generally ranging from the last years of elementary school until graduation from high school...

  • Children and adolescents in the United States
    Children and adolescents in the United States
    Children and adolescents in the United States can be regarded as one age group in the demographics of the United States.In 2010 it was estimated that 20.2% of the population of the United States were 0-14 years old ....

  • Ephebophilia
    Ephebophilia
    Ephebophilia is the sexual preference of adults for mid-to-late adolescents, generally ages 15 to 19. The term was originally used in the late 19th to mid 20th century, and has been more recently revisited by Ray Blanchard. It is one of a number of sexual preferences across age groups subsumed...

     - a sexual preference in which an adult is primarily or exclusively sexually attracted to mid to late adolescents
  • Fear of youth

Images of young people
  • Juvenile delinquency
    Juvenile delinquency
    Juvenile delinquency is participation in illegal behavior by minors who fall under a statutory age limit. Most legal systems prescribe specific procedures for dealing with juveniles, such as juvenile detention centers. There are a multitude of different theories on the causes of crime, most if not...

  • Medical School
    Medical school
    A medical school is a tertiary educational institution—or part of such an institution—that teaches medicine. Degree programs offered at medical schools often include Doctor of Osteopathic Medicine, Bachelor/Doctor of Medicine, Doctor of Philosophy, master's degree, or other post-secondary...

  • Pedophilia
    Pedophilia
    As a medical diagnosis, pedophilia is defined as a psychiatric disorder in adults or late adolescents typically characterized by a primary or exclusive sexual interest in prepubescent children...

     (or paedophilia) - a psychiatric disorder in adults or late adolescents for whom prepubescent children are the primary or exclusive sexual object of their libido
    Libido
    Libido refers to a person's sex drive or desire for sexual activity. The desire for sex is an aspect of a person's sexuality, but varies enormously from one person to another, and it also varies depending on circumstances at a particular time. A person who has extremely frequent or a suddenly...

    .
  • Rite of passage
    Rite of passage
    A rite of passage is a ritual event that marks a person's progress from one status to another. It is a universal phenomenon which can show anthropologists what social hierarchies, values and beliefs are important in specific cultures....

  • Sex education
    Sex education
    Sex education refers to formal programs of instruction on a wide range of issues relating to human sexuality, including human sexual anatomy, sexual reproduction, sexual intercourse, reproductive health, emotional relations, reproductive rights and responsibilities, abstinence, contraception, and...

  • Student voice
    Student voice
    Student voice describes the distinct perspectives and actions of young people throughout schools focused on education."Student voice is giving students the ability to influence learning to include policies, programs, contexts and principles."...

  • Suitable age and discretion
    Suitable age and discretion
    Suitable age and discretion is both a legal definition of maturity, and an alternate method of service of process by which a process server can leave a summons, subpoena, or complaint with a person living at the residence of the defendant.-Minimum age:...

  • Teen Dating Violence
    Teen dating violence
    -What is teen dating violence?:Teen dating violence is defined as the physical, sexual, or psychological/emotional violence within a dating relationship. According to the United States' Centers for Disease Control and Prevention the prevalence of teen dating violence is often misunderstood...

  • Teen drama
    Teen drama
    A teen drama is a dramatic television series with a major focus on teenage characters. The genre was relatively non-existent for the first 45 years of television; it came into prominence in the early 1990s...

     - (List of teen dramas)
  • Teen film
    Teen film
    Teen films is a film genre targeted at teenagers and young adults in which the plot is based upon the special interests of teenagers, such as coming of age, first love, rebellion, conflict with parents, teen angst, and alienation...

     - (List of teen films)
  • Teen idol
    Teen idol
    A teen idol is a celebrity who is widely idolized by teenagers; he or she is often young but not necessarily teenaged. Often teen idols are actors or pop singers, but some sports figures have an appeal to teenagers. Some teen idols began their careers as child actors...

  • Teen magazine
    Teen magazine
    Teen magazines are magazines aimed at female teenage readers. They usually consist of gossip, news, fashion tips and interviews and may include posters, stickers, small samples of cosmetics or other products and inserts. Magazines targeting teenage boys are not often called teen...

  • Teen pop
    Teen pop
    Teen pop is a subgenre of pop music that is created, marketed and oriented towards teenagers. Teen pop copies genres and styles such as pop, dance, R&B, hip hop, country and rock....

  • Timeline of children's rights in the United Kingdom
    Timeline of children's rights in the United Kingdom
    The timeline of children's rights in the United Kingdom includes a variety of events that are both political and grassroots in nature.The UK government maintains a position that UNCRC is not legally enforceable and is hence 'aspirational' only, although a 2003 ECHR ruling states that, "The human...

  • Timeline of children's rights in the United States
    Timeline of children's rights in the United States
    The timeline of young peoples' rights in the United States, including children and youth rights, includes a variety of events ranging from youth activism to mass demonstrations...

  • Young adult
    Young adult (psychology)
    A young adult, according to Erik Erikson's stages of human development, is generally a person between the age of 20 - 40, whereas an adolescent is a person between the age of 13 - 19, although definitions and opinions vary. The young adult stage in human development precedes middle adulthood. A...

  • Youth
    Youth
    Youth is the time of life between childhood and adulthood . Definitions of the specific age range that constitutes youth vary. An individual's actual maturity may not correspond to their chronological age, as immature individuals could exist at all ages.-Usage:Around the world, the terms "youth",...

  • Youth culture
  • Youth voice
    Youth voice
    Youth voice refers to the distinct ideas, opinions, attitudes, knowledge, and actions of young people as a collective body. The term youth voice often groups together a diversity of perspectives and experiences, regardless of backgrounds, identities, and cultural differences...

  • Young worker safety and health
    Young worker safety and health
    Around the world, nearly 250 million children, about one in every six children aged 5 to 17, are involved in child labor. Children can be found in almost any economic sector. However, at a global level, most of them work in agriculture ....


Further reading

  • Tennessee Williams
    Tennessee Williams
    Thomas Lanier "Tennessee" Williams III was an American writer who worked principally as a playwright in the American theater. He also wrote short stories, novels, poetry, essays, screenplays and a volume of memoirs...

     - a description of the emotional impact of puberty and adolescence is to be found in The Resemblance Between a Violin and a Coffin
  • Jon Savage
    Jon Savage
    Jon Savage , real name Jonathon Sage, is a Cambridge-educated writer, broadcaster and music journalist, best known for his award winning history of the Sex Pistols and punk music, England's Dreaming, published in 1991.-Career:...

     - a (pre)history of the development of the teenager is to be found in Teenage (Chatto and Windus
    Chatto and Windus
    Chatto & Windus has been, since 1987, an imprint of Random House, publishers. It was originally an important publisher of books in London, founded in the Victorian era....

    , 2007)