health

Biologically, aging begins with prenatal* development. The fetal period is
the time when the developing the fetus* gradually becomes a viable human
being that will be able to survive outside of the uterus*. The accumulated
successes of the prenatal period make it likely that a healthy infant will be
delivered and will grow in strength, mass, and physical ability for the next
25 to 30 years.
The first years of life are important for growth and the development
of vital functions. The changes that mark the first two years are rapid, and
they are of such importance that any delay in any area of growth or development
can be detrimental. The pediatricians who care for the newborn
encourage regular monthly check-ups to make sure that the baby’s growth
and attainment of developmental milestones are normal. Because the
baby changes so much from week to week, aging in infancy is measured in
months (as compared to years in older children and adults). Some childhood
behavioral assessments, such as the Revised Gesell Developmental
Schedules, use months as the benchmarks for children under five years of
age. The developers of these schedules note the maturational changes in
abilities and behaviors that occur each month in the first five years.
Changes in a child’s psychological profile are first noted in the initial
months of a child’s life. As the physical senses become more acute and the
perceptions of sensory stimuli become more accurate, the child begins
to make better sense of the world. One milestone taking place at around
eight months is the development of depth perception. A baby needs
about one month of crawling experience to understand that the world is
three-dimensional. A seven-month-old baby who has just started crawling
will take some risks with stairs or other possibilities for a tumble that an
eight-month-old is likely to avoid. Around 15 months, the baby develops
some self-awareness, as noted by the baby’s recognizing that the image
in the mirror is a reflection of self. Communication skills begin long
before the first words, with cries, gestures, and babbling. After two years
of age, the baby makes rapid strides with respect to language proficiency.
The social expectation in infancy is the bonding between the baby
and the primary caregiver who is usually the mother. This bonding,
known as attachment, is very important for the child’s psychosocial development.
It begins with the mother’s responding to the infant’s needs in
a way that assures the infant that life is meaningful and that the world is
predictable.
Childhood, as a period of aging, extends from age two until puberty*.
During this time the child grows continuously. Before the growth spurt
associated with puberty, an average child will achieve about 85 percent of
adult height. During childhood, the child becomes more adept at gross
motor skills (such as those used in sports) and fine motor skills (such as
those used in drawing or writing).
Psychologically, childhood is the time during which a person begins
to develop self-reliance. The child also recognizes similarities and differences
between self and others and begins to develop a self-concept. New
mental abilities enable the child to learn what is taught at school and in
other social settings. What is taught and what is seen as important to
the child’s development and education are culturally and environmentally
determined.
In the social domain, children begin spending time outside the home
and, therefore, have to learn to make friends. As they grow, their concept
of friendship evolves. Preschool children accept any playmate as a friend,
but as children grow older, they become selective. They also have to learn
rules of society. As children generally like to experiment with new surroundings
and new opportunities, they inevitably come to realize that
their actions and choices have consequences.
Adolescence is a time of rapid change in all three domains. Physically,
the adolescent is changing from a child to an adult. The onset of puberty,
accompanied by a growth spurt (coming a little earlier for girls than for
boys), is the time at which the physical body first becomes capable of
sexual reproduction. In addition to changes in reproductive organs and
reproductive functions, the secondary sexual characteristics, the traits that
distinguish the two sexes, begin to appear.
In the psychological domain, there is exploration of all kinds, as the adolescent
works to develop a sense of identity. It is important that adolescents
have positive exploratory experiences, and the hoped-for outcome is that
they have acquired a vocational goal, individual values, and a mature personality.
Adolescents are aided in this exploration by their more advanced
and more sophisticated cognitive abilities. In comparison to children, adolescents
are more capable of abstract thinking. For the first time in life,
they think about the future in a serious way. Young people at the threshold
of adult life are likely to be idealistic.
Socially, adolescents try to break away from the influence of their
parents. Peers become more important as adolescents tend to value their
perceptions and want their opinions and reactions. Adolescents are
required to maneuver in increasingly difficult environments. Their social
life can be especially rewarding at this time. However, it also can be difficult
and fraught with anxieties and conflict.