Developmental Psychology: In-Depth
Study Notes
1. Introduction to Developmental Psychology
Developmental psychology is the scientific study of how and why human beings change
over the course of their life. It covers physical, cognitive, social, and emotional development
from infancy to old age.
2. Theories of Development
2.1 Piaget’s Theory of Cognitive Development
Jean Piaget proposed four stages of cognitive development: Sensorimotor, Preoperational,
Concrete Operational, and Formal Operational. Each stage represents a qualitative
difference in how children think.
2.2 Erikson’s Psychosocial Stages
Erik Erikson proposed eight stages of psychosocial development, each centered on a specific
conflict that must be resolved for healthy psychological growth. Examples include Trust vs.
Mistrust in infancy and Identity vs. Role Confusion in adolescence.
2.3 Vygotsky’s Sociocultural Theory
Lev Vygotsky emphasized the role of social interaction and cultural tools in cognitive
development. Key concepts include the Zone of Proximal Development and scaffolding.
3. Physical Development
3.1 Prenatal and Infancy
This includes development from conception to birth, as well as early physical milestones
such as reflexes and motor skills in infancy.
3.2 Childhood and Adolescence
Children grow in height, weight, and motor coordination. Adolescence involves puberty,
hormonal changes, and brain maturation.
3.3 Adulthood and Aging
Adulthood includes physical peak in early adulthood, gradual decline in middle age, and
more significant changes in late adulthood including sensory and cognitive decline.
Study Notes
1. Introduction to Developmental Psychology
Developmental psychology is the scientific study of how and why human beings change
over the course of their life. It covers physical, cognitive, social, and emotional development
from infancy to old age.
2. Theories of Development
2.1 Piaget’s Theory of Cognitive Development
Jean Piaget proposed four stages of cognitive development: Sensorimotor, Preoperational,
Concrete Operational, and Formal Operational. Each stage represents a qualitative
difference in how children think.
2.2 Erikson’s Psychosocial Stages
Erik Erikson proposed eight stages of psychosocial development, each centered on a specific
conflict that must be resolved for healthy psychological growth. Examples include Trust vs.
Mistrust in infancy and Identity vs. Role Confusion in adolescence.
2.3 Vygotsky’s Sociocultural Theory
Lev Vygotsky emphasized the role of social interaction and cultural tools in cognitive
development. Key concepts include the Zone of Proximal Development and scaffolding.
3. Physical Development
3.1 Prenatal and Infancy
This includes development from conception to birth, as well as early physical milestones
such as reflexes and motor skills in infancy.
3.2 Childhood and Adolescence
Children grow in height, weight, and motor coordination. Adolescence involves puberty,
hormonal changes, and brain maturation.
3.3 Adulthood and Aging
Adulthood includes physical peak in early adulthood, gradual decline in middle age, and
more significant changes in late adulthood including sensory and cognitive decline.
