Development: The sequence of agerelated changes that occur as a person progresses
from conception to death.
Developmental research can be done through longitudinal and crosssectional studies.
The difference between the two is that a longitudinal study of development observes
children as they grow (ie. the child at six years, eight years, and ten years old) whereas in
a crosssectional study, children at various ages are compared.
Prenatal development: This period extends from conception to birth in three stages
known as germinal, embryonic and fetal.
The germinal stage consists of the first two weeks after conception. It all starts when a
zygote is created through fertilization. Implantation then takes place with the placenta
forming. The placenta allows oxygen and nutrients to go to the fetus, and bodily wastes
to pass out to the mother.
The embryonic stage lasts from two weeks to the end of the second month. The bodily
systems and vital organs begin to form in the embryo. Arms, legs, hands, feet, fingers,
toes, eyes, ears begin to form.
The fetal stage lasts from two months until birth. This is a period of rapid growth for the
organism that is now known as a fetus. Skeletal structures harden, sex organs develop,
and the respiratory/digestive systems mature.
Between 22 weeks and 26 weeks, the fetus reaches the age of viability, which is the age
at which a baby can survive if a premature birth occurs.
Motor development: the progression of muscular coordination needed for physical
activities, such as walking, crawling etc.
It consists of two trends, the cephalocaudal and proximodistal trend. The cephalocaudal
trend is the headtofoot direction of motor development. It means that children gain
control over their upper bodies faster than the lower, resulting in their attempts to learn
how to crawl.
The proximodistal trend is the centreoutward direction. Children learn to control the
torso before other extremities like arms. Thus, they twist their whole body to perform an
action such as reaching out for something.
Developmental norms indicate the median age when individuals display certain
behaviors and abilities. In other words, they are milestones. Temperament refers to character mood, activity level, and emotional reactivity.
According to Thomas and Chess, it categorizes children to easy, slowtowarmup and
There are various patterns of attachment that fall under secure, anxiousambivalent and
avoidant. The secure attachment is the most desirable as it fosters selfesteem, self
reliance and curiosity. The rate of each category varies by culture.
Bowlby assumed that attachment is a product of natural selection, biologically
programmed, and has survival value.
Erik Erikson’s theory proposes that there are eight stages of human development over a
life span. Each is a developmental stage, which shows characteristic patterns of behaving.
Cognitive development refers to transition in a youngster’s thinking: how they reason,
remember, and solve their problems.
Piaget’s Stage Theory of cognitive development identifies four stages marked by different
modes of thinking through which youngsters evolve. They are:
Sensorimotor period: from birth to 2 years old, this is when you start to learn how to
coordinate your sensory input and motor responses (what you see and how you move).
Preoperational period: from 27 years old, you develop your symbolic thought through
irreversibility (thinking you cannot undo an action), centration (focusing on only one part
of a problem), and egocentrism (basing things off your own viewpoint and not sharing