Adolescence in the context of "Greaser (subculture)"

Developmental psychology is the scientific study of how and why humans grow, change, and adapt across the course of their lives. Originally concerned with infants and children, the field has expanded to include adolescence, adult development, aging, and the entire lifespan. Developmental psychologists aim to explain how thinking, feeling, and behaviors change throughout life. This field examines change across three major dimensions, which are physical development, cognitive development, and social emotional development. Within these three dimensions are a broad range of topics including motor skills, executive functions, moral understanding, language acquisition, social change, personality, emotional development, self-concept, and identity formation.

Developmental psychology explores the influence of both nature and nurture on human development, as well as the processes of change that occur across different contexts over time. Many researchers are interested in the interactions among personal characteristics, the individual's behavior, and environmental factors, including the social context and the built environment. Ongoing debates in regards to developmental psychology include biological essentialism vs. neuroplasticity and stages of development vs. dynamic systems of development. While research in developmental psychology has certain limitations, ongoing studies aim to understand how life stage transitions and biological factors influence human behavior and development.

Egocentrism refers to difficulty differentiating between self and other. More specifically, it is difficulty in accurately perceiving and understanding perspectives other than one's own.Egocentrism is found across the life span: in infancy, early childhood, adolescence, and adulthood. Although egocentric behaviors are less prominent in adulthood, the existence of some forms of egocentrism in adulthood indicates that overcoming egocentrism may be a lifelong development that never achieves completion. Adults appear to be less egocentric than children because they are faster to correct from an initially egocentric perspective than children, not because they are less likely to initially adopt an egocentric perspective.

Facial hair is hair grown on the face, usually on the chin, cheeks, bottom lip and upper lip region. It is typically a secondary sex characteristic of human males. Men typically start developing facial hair in the later stages of puberty or adolescence, at around fourteen years of age, and most do not finish developing a full adult beard until around sixteen or later. However, large variations can occur; boys as young as ten have also been known to develop facial hair, and some men do not produce much facial hair at all.

Men may style their facial hair into beards, moustaches, goatees or sideburns; many others completely shave their facial hair and this is referred to as being "clean-shaven". The term whiskers, when used to refer to human facial hair, indicates the hair on the chin and cheeks.

Youth culture refers to the societal norms of children, adolescents, and young adults. Specifically, it comprises the processes and symbolic systems that are shared by the youth and are distinct from those of adults in the community.

An emphasis on clothes, popular music, sports, vocabulary, and dating typically sets youth apart from other age groups. Within youth culture, there are many constantly changing youth subcultures, which may be divided based on race, ethnicity, economic status, public appearance, or a variety of other factors.

Child development involves the biological, psychological and emotional changes that occur in human beings between birth and the conclusion of adolescence. It is—particularly from birth to five years— a foundation for a prosperous and sustainable society.

Childhood is divided into three stages of life which include early childhood, middle childhood, and late childhood (preadolescence). Early childhood typically ranges from infancy to the age of 5 years old. During this period, development is significant, as many of life's milestones happen during this time period such as first words, learning to crawl, and learning to walk. Middle childhood/preadolescence or ages 5–10 universally mark a distinctive period between major developmental transition points. Adolescence often begins around the onset of puberty, marked as menarche or spermarche, occurring between 10 and 12 years of age, and ends upon acquiring the age of maturity.. Adolescence is characterized by maturation of the body, increase in capacity for learning, and emergence of personal identity. Developmental change may occur as a result of genetically controlled processes, known as maturation, or environmental factors and learning, but most commonly involves an interaction between the two. Development may also occur as a result of human nature and of human ability to learn from the environment.

Adult development encompasses the changes that occur in biological and psychological domains of human life from the end of adolescence until the end of one's life. Changes occur at the cellular level and are partially explained by biological theories of adult development and aging. Biological changes influence psychological and interpersonal/social developmental changes, which are often described by stage theories of human development. Stage theories typically focus on "age-appropriate" developmental tasks to be achieved at each stage. Erik Erikson and Carl Jung proposed stage theories of human development that encompass the entire life span, and emphasized the potential for positive change very late in life.

The concept of adulthood has legal and socio-cultural definitions. The legal definition of an adult is a person who is fully grown or developed. This is referred to as the age of majority, which is age 18 in most cultures, although there is a variation from 15 to 21. The typical perception of adulthood is that it starts at age 18, 21, 25 or beyond. Middle-aged adulthood, starts at about age 40, followed by old age/late adulthood around age 65. The socio-cultural definition of being an adult is based on what a culture normatively views as being the required criteria for adulthood, which in turn, influences the lives of individuals within that culture. This may or may not coincide with the legal definition. Current views on adult development in late life focus on the concept of successful aging, defined as "...low probability of disease and disease-related disability, high cognitive and physical functional capacity, and active engagement with life."

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 the developed adult brain and cognitive psychology. Qualitative differences between how a child processes their waking experience and how an adult processes their waking experience are acknowledged (such as object permanence, the understanding of logical relations, and cause-effect reasoning in school-age children). Cognitive development is defined as the emergence of the ability to consciously cognize, understand, and articulate their understanding in adult terms. Cognitive development is how a person perceives, thinks, and gains understanding of their world through the relations of genetic and learning factors. Cognitive information development is often described in terms of four key components: reasoning, intelligence, language, and memory. These aspects begin to develop around 18 months of age, as infants engage with their environment playing with toys, listening to their parents, watching television, and responding to various stimuli that capture their attention all of which contribute to their cognitive growth.

Jean Piaget was a major force establishing this field, forming his "theory of cognitive development". Piaget proposed four stages of cognitive development: the sensorimotor, preoperational, concrete operational, and formal operational period. Many of Piaget's theoretical claims have since fallen out of favor. His description of the most prominent changes in cognition with age, is generally still accepted today (e.g., how early perception moves from being dependent on concrete, external actions. Later, abstract understanding of observable aspects of reality can be captured; leading to the discovery of underlying abstract rules and principles, usually starting in adolescence)

Development of the human body is the process of growth to maturity. The process begins with fertilization, where an egg released from the ovary of a female is penetrated by a sperm cell from a male. The resulting zygote develops through cell proliferation and differentiation, and the resulting embryo then implants in the uterus, where the embryo continues development through a fetal stage until birth. Further growth and development continues after birth, and includes both physical and psychological development that is influenced by genetic, hormonal, environmental and other factors. This continues throughout life: through childhood and adolescence into adulthood.